# GCN_circulars

GRB_name: GRB240101A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35457
SUBJECT: GRB 240101A: Swift/UVOT Upper Limits
DATE:    24/01/02 12:10:21 GMT
FROM:    Paul Kuin at MSSL <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240101A
168 s after the BAT trigger (Cenko et al., GCN Circ. 35448).
No optical afterglow consistent with the BAT position
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           168          318          147         >20.4
white              168         1053          334         >20.8
v                  656         4661          236         >18.7
b                  582          773           39         >18.9
u                  729          749           19         >18.3
w1                 705         5071          236         >19.5
w2                 804          824           19         >18.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.059 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240101B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35458
SUBJECT: GRB 240101B: Swift/UVOT Upper Limits
DATE:    24/01/02 12:11:38 GMT
FROM:    Paul Kuin at MSSL <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240101B
110 s after the BAT trigger (Cenko et al., GCN Circ. 35449).
No optical afterglow consistent with the XRT position
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           134          284          147         >21.1
u_FC               294          543          246         >20.1
white              134         1718          411         >21.8
v                  110         1595          130         >19.2
b                  549         1693          117         >20.5
u                  294         1669          343         >20.2
w1                 675         1644          117         >19.3
m2                 648         1619           97         >21.0
w2                 599         1741          134         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.287 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240101C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35459
SUBJECT: GRB 240101C: GRBAlpha detection
DATE:    24/01/02 15:28:27 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The short-duration GRB 240101C (Fermi/GBM detection: GCN 35451; INTEGRAL/SPI-ACS peak detection at 2024-01-01 ~12:57:24 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-01-01 12:57:24 UTC. The T90 duration measured by GRBAlpha is 1 s and the overall significance during T90 reaches 4.9 sigma in the 120-400 keV band.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240101C_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240101A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35460
SUBJECT: GRB 240101A: Terskol Zeiss-2000 optical observations
DATE:    24/01/02 16:26:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

A. Volnova (IKI), P. Phorunzij (INASAN), A. Pozanenko (IKI),  N. Pankov (IKI, HSE), S. Belkin (IKI, HSE)  report on behalf of GRB IKI FuN:

We observed the GRB 240101A  (Cenko et al., GCN 35448) with Zeiss-2000   telescope of Terskol observatory starting on 2024-01-01 (UT) 16:10:24.   Within enhanced Enhanced Swift-XRT position (Beardmore et al., GCN 35452)  we do not detect any optical objects. However we marginally detected the object at coordinates (J2000) 00:41:23.50 +8:30:58.48, which is 3.4 arcsec from XRT position (Beardmore et al., GCN 35452). Preliminary photometry of the marginally detected object is following.

Date       UT start  t-T0     Filter Exp.    OT   Err. UL.    
                     (mid, days)      (s)         S/N 


2024-01-01 16:10:24  0.1823   R      19*60   23.7 2.0 23.0  


The photometry is based on the nearby PS1 stars photometry (Lupton transformations)
RA           Dec  c      R(Lupton)
00:41:22.24 +08:31:56.6  16.277  +/-  0.012
00:41:17.90 +08:31:41.5  18.013  +/-  0.014


GRB_name: GRB240102A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35461
SUBJECT: GRB 240102A: Swift detection of a burst
DATE:    24/01/02 18:19:27 GMT
FROM:    K.L. Page at U Leicester <klp5@leicester.ac.uk>


J.D. Gropp (PSU), S. Dichiara (PSU), J. A. Kennea (PSU),
K. L. Page (U Leicester) and M. A. Williams (PSU) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 17:34:55 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240102A (trigger=1205899). Swift slewed immediately to the 
burst. The BAT on-board calculated location is 
RA, Dec 96.846, -20.024 which is 
   RA(J2000) = 06h 27m 23.0s
   Dec(J2000) = -20d 01' 26.4"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). We currently have no information regarding the
BAT light-curve. 

The XRT began observing the field at 17:37:00.6 UT, 125 seconds
after the BAT trigger. Using promptly downlinked data we find an
uncatalogued X-ray source with an enhanced position: RA, Dec 96.83800,
-20.04076 which is equivalent to:
   RA(J2000)  = 06h 27m 21.12s
   Dec(J2000) = -20d 02' 26.7"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This 
position is 66 arc-seconds from the BAT localization. This
position may be improved as more data are received; the latest position
is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 2.34
x 10^21 cm^-2 (Willingale et al. 2013). 

No afterglow is detected in the initial UVOT data products. 

Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240101B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35463
SUBJECT: GRB 240101B: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
DATE:    24/01/02 20:34:34 GMT
FROM:    I. Peretto at MarSEC (Marana Space Explorer Center) <ricerca@marsec.org>

Ivo Peretto (MarSEC, Marana Space Explorer Center, Marana Di Crespadoro, VI, Italy)

Member of:
UAI/SSV - Unione Astrofili Italiani/Sezione Stelle Variabili, GRB section.
AAVSO (American Association Variable Stars Observers)

In collaboration with: Stefano Lora (MarSEC, Marana Space Explorer Center, Marana di Crespadoro, VI, Italy)

report:
We imaged the field of GRB 240101B detected by SWIFT(trigger=1205744)
with the telescope  14â€ RC Officine Stellari of MarSEC (Marana Space Explorer Center).

The observations with a series of 120 sec exposures started at 2024-01-01 21:42:43 UT, 77 min. after the GRB trigger, with a Ritchey-Chretien telescope D=360 mm f/ 8.

at the following position:

RA(J2000) = 23h 28m 12s
Dec(J2000) = +51d 38' 43"

Weather conditions were medium with Moon illuminated 70% at 2Â° from the horizon.

We co-added 30 exposures of 120 sec each.

Start T0+      End T0+       V lim.
 77 min          137 min       20.12

We did not found any optical counterpart in A.R. 23 28 12, DEC. +51 38 43 position and in the error box of the XRT candidate.
ref.: S. B. Cenko (GSFC) et al., GCN Circular 35449

Magnitudes were estimated with the Gaia DR3  and
are not corrected for galactic dust extinction.

Reference:
https://www.marsec.org/

The message may be cited. 


GRB_name: GRB240102B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35464
SUBJECT: GRB 240102B: Fermi GBM Final Real-time Localization
DATE:    24/01/02 22:30:23 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 22:12:10 UT on 2 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240102B (trigger 725926335.090798 / 240102925).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 338.1, Dec = 46.5 (J2000 degrees, equivalent to J2000 22h 32m, 46d 30'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 3.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240102925/quicklook/glg_skymap_all_bn240102925.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240102925/quicklook/glg_healpix_all_bn240102925.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240102925/quicklook/glg_lc_medres34_bn240102925.gif


GRB_name: GRB240102A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35465
SUBJECT: GRB240102A: BOOTES-6/DPRT optical upper limit 
DATE:    24/01/02 23:18:38 GMT
FROM:    Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, S.-Y. Wu and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report:

Following the detection of GRB 240102A by Swift (Gropp et al. GCNC 35461), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) observed the GRB location starting on Jan. 2, 18:41 UT (~ 1.1 hours after trigger) in different optical bands. No new optical source is detected on the co-added images (2 x 60 s, clear-filter) within the Swift/XRT error box down to 20.2 mag. Further imaging is ongoing.

We thank the staff at Boyden Observatory for their excellent support.


GRB_name: GRB240102A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35467
SUBJECT: GRB 240102A: LCOGT Optical Upper Limits
DATE:    24/01/03 01:01:40 GMT
FROM:    Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>

R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on
behalf of a larger collaboration:

We observed the Swift GRB 240102A (Gropp et al., GCN 35461) field with the LCOGT 1-meter Sinistro instrument at the Teide Observatory, Tenerife site, on January 2, from 23:34 to January 3 00:07 UT (corresponding to 6.00 to 6.55 hours after the GRB trigger time) with the sdss r and i filters.

We performed a series of 3x300s exposures in each band.  We do not detect an uncatalogued source within the XRT error region in either band.  This result is consistent with other optical upper limits (Hu et al., GCN 35465).

The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference:

r > 22.9
i > 22.3

These magnitudes are not corrected for galactic extinction.


GRB_name: GRB240102B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35468
SUBJECT: GRB 240102B (Fermi GBM trigger 725926335/240102925) is not a GRB
DATE:    24/01/03 01:42:19 GMT
FROM:    Cori Fletcher at USRA <cfletcher@usra.edu>

C. Fletcher (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:

"The Fermi Gamma-ray Burst Monitor (GBM) trigger 725926335/240102925 at 22:12:10.09 UT
on 02 January 2024, tentatively classified as a GRB 240102B (GCN 35464), is in fact not due
to a GRB. This trigger is likely due to particle activity."


GRB_name: GRB240102A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35469
SUBJECT: GRB 240102A: Swift-XRT refined Analysis
DATE:    24/01/03 07:00:54 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo
(INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU) and P.A. Evans report
on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 240102A, from 113 s to 28.3
ks after the  BAT trigger. The data comprise 91 s in Windowed Timing
(WT) mode (the first 10 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. The best available XRT position
 (using the promptly downlinked event data, the XRT-UVOT alignment and
matching UVOT field sources to the USNO-B1 catalogue) is RA, Dec =
96.83800, -20.04076 which is equivalent to:

RA (J2000): 06 27 21.12
Dec(J2000): -20 02 26.7

with an uncertainty of 1.9 arcsec (radius, 90% confidence).

The late-time light curve (from T0+4.7 ks) can be modelled with a
power-law decay with a decay index of alpha=0.5 (+/-0.3).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.74 (+0.11, -0.10). The
best-fitting absorption column is  3.3 (+0.6, -0.5) x 10^21 cm^-2, in
excess of the Galactic value of 2.3 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 4.3 x 10^-11 (5.7 x 10^-11) erg
cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Total column:      3.3 (+0.6, -0.5) x 10^21 cm^-2
Galactic foreground: 2.3 x 10^21 cm^-2
Excess significance: 3.1 sigma
Photon index:      1.74 (+0.11, -0.10)

If the light curve continues to decay with a power-law decay index of
0.5, the count rate at T+24 hours will be 9.8 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.2 x
10^-13 (5.6 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01205899.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240101B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35470
SUBJECT: GRB 240101B: Swift-XRT refined Analysis
DATE:    24/01/03 09:51:11 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G.
Bernardini (INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto) and P.A. Evans report on behalf of the
Swift-XRT team:

We have analysed 6.9 ks of XRT data for GRB 240101B, from 138 s to
126.6 ks after the  BAT trigger. The data comprise 189 s in Windowed
Timing (WT) mode (the first 12 s were taken while Swift was slewing)
with the remainder in Photon Counting (PC) mode. 

The late-time light curve (from T0+5.0 ks) can be modelled with a
power-law decay with a decay index of alpha=0.80 (+0.33, -0.29).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.28 (+0.14, -0.13). The
best-fitting absorption column is  6.5 (+/-0.8) x 10^21 cm^-2, in
excess of the Galactic value of 2.9 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.39 (+0.29, -0.27)
and a best-fitting absorption column of 7.9 (+2.0, -1.8) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.8 x 10^-11 (9.4 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.9 (+2.0, -1.8) x 10^21 cm^-2
Galactic foreground: 2.9 x 10^21 cm^-2
Excess significance: 4.7 sigma
Photon index:      2.39 (+0.29, -0.27)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01205744.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240102A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35471
SUBJECT: GRB 240102A: Enhanced Swift-XRT position
DATE:    24/01/03 10:00:18 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 4654 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 240102A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 96.83931, -20.04096 which is equivalent
to:

RA (J2000): 06h 27m 21.43s
Dec (J2000): -20d 02' 27.5"

with an uncertainty of 2.2 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB240101B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35472
SUBJECT: GRB 240101B: Swift-BAT refined analysis
DATE:    24/01/03 14:03:29 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),  S. B. Cenko (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240101B (trigger #1205744)
(Cenko, et al., GCN Circ. 35449).  The BAT ground-calculated position is
RA, Dec = 352.147, 51.646 deg which is
   RA(J2000)  =  23h 28m 35.3s
   Dec(J2000) = +51d 38' 46.9"
with an uncertainty of 3.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a single peak from approximately T+0
To T+18 seconds.  There is a possible precursor at T-50 sec.

T90 (15-350 keV) is 43.1 +- 12.6 sec (estimated error including systematics).
The time-averaged spectrum from T+2.18 to T+48.32 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.70 +- 0.26.  The fluence in the 15-150 keV band is 4.6 +- 0.8 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+10.28 sec in the 15-150 keV band
is 0.5 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1205744/BA/


GRB_name: GRB240101A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35473
SUBJECT: GRB 240101A: Swift-BAT refined analysis
DATE:    24/01/03 14:06:48 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>

A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC),  S. B. Cenko (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU),  M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-10 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240101A (trigger #1205708)
(Cenko, et al., GCN Circ. 35448).  The trigger time, which was unavailable in the
first circular was 2024-01-01 at 14:20:17.331 UTC.  The BAT ground-calculated position is
RA, Dec = 10.289, 8.540 deg which is
   RA(J2000)  =  00h 41m 09.5s
   Dec(J2000) = +08d 32' 25.3"
with an uncertainty of 3.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 66%.

The mask-weighted light curve shows a weak, complex structure lasting from
About T-5 to T+10 seconds.  T90 (15-350 keV) is 15.8 +- 6.1 sec (estimated error
including systematics).

The time-averaged spectrum from T-1.94 to T+20.28 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.03 +- 0.34.  The fluence in the 15-150 keV band is 3.3 +- 0.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+2.11 sec in the 15-150 keV band
is 0.9 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1205708/BA/


GRB_name: GRB231230A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35474
SUBJECT: GRB 231230A: Swift-BAT refined analysis
DATE:    24/01/03 14:07:21 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC <hkrimm@nsf.gov>

S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),  H. A. Krimm (NSF),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 231230A (trigger #1205319)
(Moss, et al., GCN Circ. 35436).  The BAT ground-calculated position is
RA, Dec = 245.223, 58.132 deg which is
   RA(J2000)  =  16h 20m 53.5s
   Dec(J2000) = +58d 07' 54.2"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.

The mask-weighted light curve shows a complex structure extending from
around T+0 to T+20.  T90 (15-350 keV) is 15.2 +- 0.9 sec (estimated error including systematics).

The time-averaged spectrum from T+0.26 to T+17.26 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.28 +- 0.10.  The fluence in the 15-150 keV band is 2.1 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+7.64 sec in the 15-150 keV band
is 2.2 +- 0.4 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1205319/BA/


GRB_name: GRB240102A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35475
SUBJECT: GRB 240102A: Swift/UVOT Upper Limits
DATE:    24/01/03 15:38:51 GMT
FROM:    Alexander Belles at PSU <aub1461@psu.edu>

A. Belles (PSU) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240102A
113 s after the BAT trigger (Gropp et al., GCN Circ. 35461).
No optical afterglow consistent with the XRT position
(Goad et al., GCN Circ. 35471) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           135          285          147         >20.7
u_FC               294          544          246         >19.9
white              135         1196          353         >21.1
v                  113         1246           90         >18.8
b                  550         1172           58         >19.5
u                  294         1314          299         >20.0
w1                 676         1295           78         >19.0
m2                 823         1270           58         >18.7
w2                 600         1221           78         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.176 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240102A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35476
SUBJECT: GRB 240102A: Swift-BAT refined analysis
DATE:    24/01/03 23:33:27 GMT
FROM:    Amy <yarleen@gmail.com>

M. J. Moss (GSFC), S. D. Barthelmy (GSFC),
J.D. Gropp (PSU), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 240102A (trigger #1205899)
(Gropp et al., GCN Circ. 35461).  The BAT ground-calculated position is
RA, Dec = 96.848, -20.011 deg which is
   RA(J2000)  =  06h 27m 23.5s
   Dec(J2000) = -20d 00' 39.0"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve show some weak emission that starts at ~T+8 s
and ends at ~T+140 s. T90 (15-350 keV) is 119.00 +- 30.59 sec
(estimated error including systematics).

The time-averaged spectrum from T+8.00 to T+142.00 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
2.00 +- 0.22.  The fluence in the 15-150 keV band is 8.5 +- 1.3 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+65.00 sec in the 15-150 keV band
is 0.4 +- 0.1 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1205899/BA/


GRB_name: GRB231220A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35477
SUBJECT: GRB 231220A: Swift-UVOT upper limit
DATE:    24/01/04 03:26:25 GMT
FROM:    noelklin@umbc.edu

N. Klingler (UMBC/NASA-GSFC/CRESST II) reports on behalf of the Swift-UVOT team:

Swift-UVOT has performed follow-up observations of the Swift-BAT/GUANO-detected and Fermi-GBM-detected GRB 231220A, collecting 2.6 ks of data between T0+35.2 ks and T0+47.8 ks.  No candidate counterpart was detected.  The 3 sigma limiting (AB) magnitude in the White filter near the center of the BAT/GUANO localization (GCN 35409) is >23.20.


GRB_name: GRB240101C
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35478
SUBJECT: GRB 240101C: AstroSat CZTI detection
DATE:    24/01/04 04:38:33 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

P. K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a short-duration GRB 240101C which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35451), and GRBAlpha (Dafcikova et al., GCN Circ. 35459).

The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-01 12:57:23.80 UTC. The measured peak count rate associated with the burst is 881 (+732, -43) counts/s above the background in the combined data of all quadrants, with a total of 69 (+31, -22) counts. The local mean background count rate was 331 (+13, -43) counts/s. Using cumulative rates, we measure a T90 of 0.13 (+0.06, -0.04) s.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240102C
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35479
SUBJECT: GRB 240102C: AstroSat CZTI detection
DATE:    24/01/04 04:55:12 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

P. K. Navaneeth (IUCAA), J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240102C which was also detected by Fermi (Trigger Num. 725857207), and Konus-IPN.

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-02 03:00:04.50 UTC. The measured peak count rate associated with the burst is 170 (+35, -32) counts/s above the background in the combined data of all quadrants, with a total of 1021 (+191, -224) counts. The local mean background count rate was 336 (+2, -4) counts/s. Using cumulative rates, we measure a T90 of 10 (+4, -3) s.

The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-02 03:00:02.75 UTC. The measured peak count rate associated with the burst is 285 (+52, -45) counts/s above the background in the combined data of two quadrants (out of four), with a total of 2066 (+305, -324) counts. The local mean background count rate was 757 (+3, -4) counts/s. We measure a T90 of 19 (+2, -8) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240101C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35482
SUBJECT: GRB 240101C: Swift/BAT-GUANO detection of a short burst
DATE:    24/01/05 02:17:35 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:

Swift/BAT did not localize GRB 240101C onboard (T0: 2024-01-01T12:57:23.76 UTC, Fermi GBM Trig 725806648, GRBAlpha GCN 35459, AstroSat CZTI GCN 35478). 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 11.2 in a 0.128 s analysis time bin, starting at T0 s. 

NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 4.2.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240101B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35483
SUBJECT: GRB 240101B: 1.3m DFOT optical upper limit
DATE:    24/01/05 11:17:13 GMT
FROM:    Amit Kumar Ror at ARIES <mitturor77894@gmail.com>

Amit K. Ror, Rahul Gupta, Amar Aryan, and Shashi B. Pandey (ARIES) report:
We observed the field of the GRB 240101B detected by Swift (Cenko et al.
2024, GCN 35449) with the 1.3m Devasthal Fast Optical Telescope (DFOT),
located at the Devasthal Observatory of the Aryabhatta Research Institute
of Observational Sciences (ARIES), India. The observations were started on
2024-01-02 at 12:43:55 UT, i.e., ~ 0.68 days after the BAT trigger. We have
taken multiple frames with an exposure time of 300 s in the R filter. We
stacked the images after the alignment. We did not detect any optical
afterglow in our stacked image within the enhanced Swift-XRT error box
(Evans et al., 2024, GCN 35455). We obtain the following preliminary
3-sigma upper limit in the stacked image:

Date Start_UT T_start-T0 (days) Filter  Exp time (s)  Limiting magnitude
=========================================================
2024-01-02 12:43:55    ~0.68      R     300*12       > 21.7


Our non-detection is consistent with Zheng et al. 2024, GCN 35454; Kuin et
al. 2024, GCN 35458; and Peretto 2024, GCN 35463.

The magnitude is not corrected for the Galactic extinction in the direction
of the burst. Photometric calibration is performed using the standard stars
from the USNO-B1.0 catalog. This circular may be cited.


GRB_name: GRB240102A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35484
SUBJECT: GRB 240102A: 1.3m DFOT optical upper limit
DATE:    24/01/05 11:20:00 GMT
FROM:    Amit Kumar Ror at ARIES <mitturor77894@gmail.com>

Amit K. Ror, Rahul Gupta, Amar Aryan, and Shashi B. Pandey (ARIES) report:

We observed the field of GRB 240102A detected by Swift (Gropp et al. 2024,
GCN 35461) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located
at the Devasthal Observatory of the Aryabhatta Research Institute of
Observational Sciences (ARIES), India. The observations were started on
2024-01-02 at 18:23:56 UT, i.e., ~ 49 minutes after the BAT trigger. We
have taken multiple frames with an exposure time of 300 s in the R filter.
We stacked the images after the alignment. We did not detect any optical
afterglow in our stacked image within the enhanced Swift-XRT error box
(Goad et al., 2024, GCN 35471). We obtain the following preliminary 3-sigma
upper limit in the stacked image:


Date Start_UT T_start-T0 (minutes) Filter  Exp time (s)  Limiting magnitude
=========================================================
2024-01-02 18:23:56    ~49     R     300*20     > 21.5


Our non-detection is consistent with the observations of Hu et al. 2024,
GCN 35465; Strausbaugh et al. 2024, GCN 35467; and Belles et al. 2024, GCN
35475.

The magnitude is not corrected for the Galactic extinction in the direction
of the burst. Photometric calibration is performed using the standard stars
from the USNO-B1.0 catalog. This circular may be cited.


GRB_name: GRB240101A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35486
SUBJECT: GRB 240101A: 1.3m DFOT optical observations
DATE:    24/01/05 18:01:34 GMT
FROM:    Rahul Gupta at Aryabhatta Research Institute of Observational Sciences (ARIES) India <rahulbhu.c157@gmail.com>

Rahul Gupta, Amit K. Ror, Amar Aryan, and Shashi B. Pandey (ARIES) report
on behalf of a larger collaboration:

We performed the optical follow-up observations of the field of new year
burst GRB 240101A detected by Swift (Cenko et al. 2024, GCN 35448),
utilizing the 1.3m Devasthal Fast Optical Telescope (DFOT) situated at the
Devasthal Observatory of the Aryabhatta Research Institute of Observational
Sciences (ARIES), India. Our observations started on 2024-01-01 at 15:37:15
UT, approximately 1.28 hours post-detection. Multiple frames were captured in
the R filter with an exposure time of 300 seconds each. Subsequently, we
aligned and stacked the images. In our stacked image, no optical afterglow
was detected within the enhanced Swift-XRT error box (Beardmore et al.
2024, GCN 35452), resulting in a preliminary 3-sigma upper limit of ~ 22.4
mag. This non-detection is consistent with the observations of Zheng et al.
2024, GCN 35453; Kuin et al. 2024, GCN 35457; and Volnova et al. 2024, GCN
35460.

Additionally, we observed a potential signature of very faint optical
emission at the position of the optical source reported by Volnova et al.
2024, GCN 35460. The detected faint optical source (if related) may
potentially represent a candidate afterglow or the associated host galaxy
of GRB 240101A. Further deep follow-up observations using larger telescopes
will help to unveil the true nature of the optical source.

The magnitude is not corrected for the Galactic extinction in the direction
of the burst. Photometric calibration is performed using the standard stars
from the USNO-B1.0 catalog. This circular may be cited.


GRB_name: GRB240101C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35488
SUBJECT: GRB GRB240101C: Fermi GBM observation
DATE:    24/01/05 18:41:54 GMT
FROM:    sumanbala2210@gmail.com

S. Bala (USRA), B. Mailyan (Florida Tech) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:


"At 12:57:23.76 UT on 01 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240101C (trigger 725806648/240101540),
which was also detected by the Swift/BAT-GUANO (J. DeLaunay et. al. 2023, GCN 35482), 
GRBAlpha (Dafcikova et al. GCN Circ. 35459) and AstroSat CZTI (Navaneeth et al. 
GCN 35478). The Fermi GBM on-ground calculated location, using the Fermi GBM 
trigger data has been reported at GCN 35451.

The angle from the Fermi LAT boresight at the GBM trigger time is 69.0 degrees.

The GBM light curve consists of one very short peak
with a duration (T90) of about 0.35 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.256 s is
best fit by a Comptonized Epeak function with Epeak = 286.4 +/- 21.8 keV, and
alpha = 0.10 +/- 0.14.

The event fluence (10-1000 keV) in this time interval is
(1.19 +/- 0.07)E-6 erg/cm^2. The 64-msec peak photon flux measured
starting from T0 in the 10-1000 keV band
is 460.9 +/- 77.4 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 242.7 +/- 28.8 keV, alpha = 0.30 +/- 0.20 and beta = -2.50 +/- 0.39.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240101C
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35489
SUBJECT: IPN triangulation of GRB 240101C (short)
DATE:    24/01/05 19:17:11 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:

The short-duration GRB 240101C
(Fermi-GBM detection: The Fermi GBM team, GCN 35451;
Bala et al., GCN 35488;
GRBAlpha detection: Dafcikova et al., GCN 35459;
AstroSat-CZTI detection: Navaneeth et al., GCN 35478;
Swift-BAT/GUANO detection: DeLaunay et al., GCN 35482)
has been detected by Fermi (GBM trigger 725806648), Swift (BAT), GRBAlpha, Konus-Wind, INTEGRAL (SPI-ACS), and AstroSat (CZTI),
so far, at about 46644 s UT (12:57:24).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  358.487 (23h 53m 57s) +28.743 (+28d 44' 36")
 Corners:
    0.797 (00h 03m 11s) +24.032 (+24d 01' 56")
    1.127 (00h 04m 30s) +23.926 (+23d 55' 33")
  355.725 (23h 42m 54s) +33.705 (+33d 42' 18")
  355.318 (23h 41m 16s) +33.852 (+33d 51' 06")
 ---------------------------------------------
The error box area is 2.5  sq. deg and its maximum
dimension is 11.15 deg (the minimum one is 14 arcmin).
The Sun distance was 90 deg.

This localization may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM localizations.


A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240101_T46643/IPN/


GRB_name: GRB240106A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35490
SUBJECT: GRB 240106A: Fermi GBM Final Real-time Localization
DATE:    24/01/06 00:44:36 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 00:34:08 UT on 6 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240106A (trigger 726194053.403458 / 240106024).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 8.0, Dec = 53.7 (J2000 degrees, equivalent to J2000 00h 32m, 53d 42'), with a statistical uncertainty of 1.7 degrees.

The angle from the Fermi LAT boresight is 17.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240106024/quicklook/glg_skymap_all_bn240106024.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240106024/quicklook/glg_healpix_all_bn240106024.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240106024/quicklook/glg_lc_medres34_bn240106024.gif


GRB_name: GRB240106B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35492
SUBJECT: GRB 240106B: Fermi GBM Final Real-time Localization
DATE:    24/01/06 06:32:05 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 06:21:20 UT on 6 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240106B (trigger 726214885.929338 / 240106265).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 239.8, Dec = -22.5 (J2000 degrees, equivalent to J2000 15h 59m, -22d 30'), with a statistical uncertainty of 5.4 degrees.

The angle from the Fermi LAT boresight is 43.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240106265/quicklook/glg_skymap_all_bn240106265.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240106265/quicklook/glg_healpix_all_bn240106265.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240106265/quicklook/glg_lc_medres34_bn240106265.gif


GRB_name: GRB240107A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35495
SUBJECT: GRB 240107A: MAXI/GSC detection
DATE:    24/01/08 02:37:58 GMT
FROM:    Hitoshi Negoro at Nihon University/MAXI team <negoro.hitoshi@nihon-u.ac.jp>

T. Kurihara (JAXA), H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN),
T. Sakamoto, M. Serino, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU),
Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto, E.Goto (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.),
I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa (JAXA),
Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.),
M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.),
K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), and W. Iwakiri (Chiba U.)

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient source
at 19:15:47 UT on January 7, 2023.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (298.014 deg, -68.228 deg) = (19 52 03, -68 13 39) (J2000)
with a 90% C.L. statistical error of 0.41 deg and an additional systematic uncertainty of 0.1 deg
(90% containment radius). The X-ray flux averaged over the scan was 114 +- 24 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (296.278, -67.736) deg = (19 45 06, -67 44 09) (J2000)
(R.A., Dec) = (296.022, -68.496) deg = (19 44 05, -68 29 45) (J2000)
(R.A., Dec) = (303.762, -68.679) deg = (20 15 02, -68 40 44) (J2000)
(R.A., Dec) = (303.766, -67.913) deg = (20 15 03, -67 54 46) (J2000)
There was no significant excess flux in the previous transit at 17:42 UT
and in the next transit at 20:48 UT with an upper limit of 20 mCrab for each.


GRB_name: GRB240106A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35497
SUBJECT: GRB 240106A: GRBAlpha detection
DATE:    24/01/08 09:43:50 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240106A (Fermi/GBM detection: GCN 35490; CALET/CGBM detection: trigger no. 1388536424; INTEGRAL/SPI-ACS peak detection at 2024-01-06 ~00:36:35 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-01-06 00:36:37 UTC. The T90 duration measured by GRBAlpha is 148 s and the overall significance during T90 reaches 16 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240106A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240109A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35501
SUBJECT: GRB 240109A: Swift detection of a short burst
DATE:    24/01/09 04:15:10 GMT
FROM:    David Palmer at LANL <palmer@lanl.gov>


S. Dichiara (PSU), D. M. Palmer (LANL) and M. H. Siegel (PSU) report
on behalf of the Neil Gehrels Swift Observatory Team:

At 04:01:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240109A (trigger=1207446).  Due to a Sun constraint,
Swift did not slew immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 301.318, +16.578 which is 
   RA(J2000) = 20h 05m 16s
   Dec(J2000) = +16d 34' 39"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single spike
structure with a duration of about 0.25 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0.1 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 00:14 UT on 2024 March 01. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is S. Dichiara (sbd5667 AT psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240107A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35503
SUBJECT: GRB 240107A: AstroSat CZTI detection
DATE:    24/01/09 07:01:04 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240107A which was also detected by MAXI-GSC (Kurihara et al., GCN Circ. 35495).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-01-07 19:16:32.4 UTC. The measured peak count rate associated with the burst is 191 (+66, -13) counts/s above the background in the combined data of three quadrants (out of four), with a total of 6807 (+1623, -1781) counts. The local mean background count rate was 1088 (+3, -4) counts/s. We measure a T90 of 160 (+18, -10) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230812B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35505
SUBJECT: GRB 230812B: further radio observations with the VLA
DATE:    24/01/09 13:22:01 GMT
FROM:    Stefano Giarratana at University of Bologna <s.giarratana@ira.inaf.it>

S. Giarratana (University of Bologna, INAF-IRA), M. Giroletti
(INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.)

At 18:39:38 UT on 2023 August 29 (T_mid = 17.0 days post-burst)
and at 17:37:02 UT on 2023 September 19 (T_mid = 38.0 days
post-burst) the Karl G. Jansky VLA started observing the field of
GRB 230812B (Fermi GBM team, GCN 34386) at a central
frequency of 6 and 10 GHz.

The standard J1331+3030 (3C286) was used as bandpass and
flux density calibrator, while J1637+4717 was used as complex
gain calibrator.

From a preliminary analysis, the radio counterpart of GRB 230812B
(Rhodes et al., GCN 34433; de Ugarte Postigo et al., GCN 34468;
Giarratana et al., GCN 34552; Chandra et al., GCN 34735) is no
longer detected. We derive the following upper limits (UL; 3sigma).

=====================================================
T_mid    Freq     UL     r.m.s.    Beam         PA
[days]   [GHz]   [uJy]   [uJy/b]   [arcsec]     [deg]
=====================================================
17.0     6        24     8         0.68x0.29    -71
17.0     10       24     8         0.50x0.18    -65
38.0     6        21     7         0.60x0.29    -74
38.0     10       21     7         0.40x0.18    -70
=====================================================

We note that the 6 GHz upper limit at 17 days post-burst seems
inconsistent with the detection reported by Chandra et al., GCN 34735,
at the same frequency.

We would like to thank the staff of the VLA for approving, executing,
and processing the observations.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc.

These observations were carried out as part of project SF161095,
approved in the framework of the Fermi - NRAO joint program agreement.


GRB_name: GRB230818A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35506
SUBJECT: GRB 230818A: further radio observations with the VLA
DATE:    24/01/09 13:30:14 GMT
FROM:    Stefano Giarratana at University of Bologna <s.giarratana@ira.inaf.it>

S. Giarratana (University of Bologna, INAF-IRA), M. Giroletti
(INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.)


At 22:56:54 UT on 2023 September 18 (T_mid = 31.0 days post-burst)
and at 17:12:33 UT on 2023 November 28 (T_mid = 101.8 days
post-burst) the Karl G. Jansky VLA started observing the field of
GRB 230818A (Fermi GBM team, GCN 34478; Tohuvavohu et al.,
GCN 34479) at a central frequency of 6 and 10 GHz.

The standard J1331+3030 (3C286) was used as bandpass and
flux density calibrator, while J1912+3740 was used as complex
gain calibrator.

From a preliminary analysis, we do not detect the radio counterpart
of GRB 230818A. We derive the following upper limits (UL; 3sigma).

=====================================================
T_mid    Freq     UL     r.m.s.    Beam         PA
[days]   [GHz]   [uJy]   [uJy/b]   [arcsec]     [deg]
=====================================================
31.0     6        24     8         0.34x0.31    -64
31.0     10       24     8         0.22x0.19    -75
101.8    6        30     10        13.2x9.94    -87
101.8    10       24     8         9.05x6.06    -82
=====================================================

We would like to thank the staff of the VLA for approving, executing,
and processing the observations.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc.

These observations were carried out as part of project SF161095,
approved in the framework of the Fermi - NRAO joint program agreement.


GRB_name: GRB231215A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35507
SUBJECT: GRB 231215A: radio detection with the VLA
DATE:    24/01/09 13:31:45 GMT
FROM:    Stefano Giarratana at University of Bologna <s.giarratana@ira.inaf.it>

S. Giarratana (University of Bologna, INAF-IRA), M. Giroletti
(INAF-IRA), G. Ghirlanda (INAF-OAB), N. Di Lalla (Stanford Univ.),
N. Omodei (Stanford Univ.)

At 03:57:39 UT on 2023 December 20 (T_mid = 4.8 days post-burst) the
Karl G. Jansky VLA started observing the field of GRB 231215A
(D'Avanzo et al., GCN 35343) at a central frequency of 6 and 10 GHz.

The standard J0542+4951 was used as bandpass and flux density
calibrator, while J0102+5824 was used as complex gain calibrator.

From a preliminary analysis, an unresolved radio source (Rhodes et al.,
GCN 35397) is clearly detected at both frequencies at a position:

RA: 00:38:57.53 +- 0.05
Dec: +57:38:50.7 +- 0.6

The surface brightness peak is 61 uJy/beam and 128 uJy/beam at 6
and 10 GHz, respectively. The r.m.s. noise level of the images is
7 uJy/beam at both 6 and 10 GHz.

The synthesized beams are 13.1 x 9.9 arcsec (PA: -66deg) at 6 GHz
and 7.7 x 6.0 arcsec (PA: -59deg) at 10 GHz.

We would like to thank the staff of the VLA for approving, executing,
and processing the observations.

The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc.

These observations were carried out as part of project SF161095,
approved in the framework of the Fermi - NRAO joint program agreement.


GRB_name: GRB240101C
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35508
SUBJECT: Konus-Wind detection of GRB 240101C
DATE:    24/01/09 15:07:11 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short-duration GRB 240101C
(Fermi-GBM detection: The Fermi GBM team, GCN 35451;
Bala et al., GCN 35488;
GRBAlpha detection: Dafcikova et al., GCN 35459;
AstroSat-CZTI detection: Navaneeth et al., GCN 35478;
Swift-BAT/GUANO detection: DeLaunay et al., GCN 35482;
IPN triangulation: Svinkin et al., GCN 35489)
triggered Konus-Wind at T0=46643.329 s UT (12:57:23.329).

The burst light curve shows a single pulse
which starts at ~T0-0.1 s and has a total duration of ~0.3 s.
The emission is seen up to ~4 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240101_T46643/

As observed by Konus-Wind, the burst
had a fluence of 1.39(-0.19,+0.21)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.002 s,
of 1.57(-0.41,+0.43)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.19(-0.41,+0.52)
and Ep = 326(-56,+80) keV (chi2 = 15/22 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.4
(chi2 = 15/21 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240109B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35511
SUBJECT: GRB 240109B: Fermi GBM Final Real-time Localization
DATE:    24/01/09 21:41:29 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 21:30:52 UT on 9 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240109B (trigger 726528657.301666 / 240109896).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 241.5, Dec = -44.3 (J2000 degrees, equivalent to J2000 16h 06m, -44d 17'), with a statistical uncertainty of 12.2 degrees.

The angle from the Fermi LAT boresight is 91.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240109896/quicklook/glg_skymap_all_bn240109896.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240109896/quicklook/glg_healpix_all_bn240109896.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240109896/quicklook/glg_lc_medres34_bn240109896.gif


GRB_name: GRB240106A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35513
SUBJECT: GRB 240106A: Glowbug gamma-ray detection
DATE:    24/01/09 22:03:58 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J. E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge (MSFC), and M.S. Briggs (UAH) report:                                                                                                                                                                                                                                                   
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240106A, which was also detected by Fermi/GBM, GRBAlpha, CALET/CGBM, and INTEGRAL/SPI-ACS (GCN #35490, #35497). 
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-06 00:34:17.784 with a duration of 146.4 s and a total significance of over 97 sigma.  
 
The light curve comprises a complex multi-peaked structure with the brightest interval from T0+127.5s to T0+146.4s. Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over the brightest interval results in a photon index dN/dE~E^x of x=1.1 and a cutoff energy ("Epeak") of 281 keV.  The modeled 10-10000 keV fluence for the brightest interval is 1e-05 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240106B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35514
SUBJECT: GRB 240106B: Glowbug gamma-ray detection
DATE:    24/01/09 22:04:39 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J. E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge (MSFC), and M.S. Briggs (UAH) report:                                                                                                                                                                                                                                                   
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240106B, which was also detected by Fermi/GBM (GCN #35492). 
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-06 06:21:18.624 with a duration of 6.1 s and a total significance of about 17.5 sigma.  The light curve comprises a single peak.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=0.9 and a cutoff energy ("Epeak") of 330 keV.  The modeled 10-10000 keV fluence is 1.2e-06 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB231214A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35515
SUBJECT: GRB 231214A: ATCA Radio Upper Limits
DATE:    24/01/09 22:18:17 GMT
FROM:    agul8829@uni.sydney.edu.au

A. Gulati (USyd), G. E. Anderson (Curtin), J. K. Leung (UofT/HUJI), S. D. Ryder (Macquarie), A. J. van der Horst (GWU), S. Chastain (UNM), and L. Rhodes (Oxford) on behalf of the ATCA PanRadio GRB collaboration

We observed long GRB 231214A (Fermi GBM Collaboration, GCN 35334; R. Brivio et al., GCN 35335) as part of the The Australia Telescope Compact Array (ATCA) "PanRadio GRB" Large Project C3542 (PI: G. Anderson) at 5.5, 9, 16.7, 21.2, 33 and 35 GHz on 2023-12-16 and at 5.5 and 9 GHz on 2023-12-21 UT. 

No radio sources were detected near the Swift/XRT enhanced position (J. P. Osborne et al., GCN 35350)in either observation epoch. The 3-sigma upper limits for the 9 GHz observations are 73 and 81 uJy respectively.

We thank the CSIRO Space and Astronomy staff for supporting these observations.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.


GRB_name: GRB240108A
Detection_method: IBAS
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35516
SUBJECT: GRB 240108A: Glowbug gamma-ray detection
DATE:    24/01/10 04:02:03 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J. E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge (MSFC), and M.S. Briggs (UAH) report:

The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240108A, which was also a weak detection by INTEGRAL IBAS (Trigger 10461).

Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-08 19:18:29.488 with a duration of 10.2 s and a total significance of about 16.9 sigma.  The light curve comprises a single peak.

Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.4 and a cutoff energy ("Epeak") of 376 keV.  The modeled 10-10000 keV fluence is 1.6e-06 erg/cm^2.

The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.

Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.

[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006

Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240110A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35518
SUBJECT: GRB 240110A: AstroSat CZTI detection
DATE:    24/01/11 15:28:45 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240110A which was also detected by GECAM (Trigger Num. 257), and INTEGRAL-SPIACS (Trigger Num. 10463).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-10 14:53:30.07 UTC. The measured peak count rate associated with the burst is 348 (+65, -56) counts/s above the background in the combined data of all quadrants, with a total of 3083 (+366, -468) counts. The local mean background count rate was 1334 (+6, -5) counts/s. We measure a T90 of 16 (+4, -2) s from the cumulative Veto light curve.

The source was also detected in the CZT detectors in the 20-200 keV energy range but we cannot make quantitative inferences due to data quality issues.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240109A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35519
SUBJECT: GRB 240109A: Fermi GBM Observation
DATE:    24/01/11 20:28:52 GMT
FROM:    Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>

O.J. Roberts (USRA/NASA-MSFC) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 04:01:35.21 UT on 09 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240109A (trigger 726465700/240109168).
which was also detected by Swift-BAT (S. Dichiara et al. 2024, GCN 35501).
The Fermi GBM on-ground Localization is consistent with the Swift-BAT position.

The angle from the Fermi LAT boresight is 79 degrees using the Swift-BAT position.

The GBM light curve consists of a single peak with a duration (T90)
of about 0.26 s (50-300 keV). The time-averaged spectrum
from T0-0.12 to T0+0.12 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.0 +/- 0.3 and the cutoff energy,
parameterized as Epeak, is 305 +/- 179 keV.

The event fluence (10-1000 keV) in this time interval is
(1.6 +/- 0.4)E-07 erg/cm^2. The 0.064-sec peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band is 6 +/- 1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240112A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35520
SUBJECT: GRB 240112A: GECAM detection of a burst
DATE:    24/01/12 07:03:01 GMT
FROM:    Chenwei Wang at IHEP <cwwang@ihep.ac.cn>

Chen-Wei Wang, Shao-Lin Xiong report on behalf of the GECAM team:
GECAM-B was triggered in-flight by a bright burst, tentatively named as GRB 240112A (see below),at 2024-01-12T05:41:25.850 UTC (denoted as T0).

GECAM-B localized this burst to the following position (J2000): 
Ra: 290.4 deg 
Dec: 18.4 deg
Err: 3.6 deg (1-sigma, statistical only)
We note that, although this in-flight location is very preliminary, it is generally consistent with SGR J1935+2154 within the error, therefore we suggest that it could be possibly from this magnetar. However, we cannot exclude the possibility of other origins at this moment.

According to the realtime alert data of GECAM-B, this burst mainly consists of two pulses
with a duration of about 3 s. The time-averaged spectrum from T0-0.2 to T0+3.8 s 
could be adequately fit by a power law with high energy exponential cutoff function 
with a fluence of about 5E-6 erg/cm^2 in 20-1000 keV.

The GECAM light curve could be found here:
http://twiki.ihep.ac.cn/pub/GECAM/GRBList/240112_lc.png

We note that these results are based on realtime alert data and thus very preliminary. 
Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor
(GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B)
launched in Dec. 2020. As the third member of GECAM constellation, 
GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. 
GECAM mission is funded by the Chinese Academy of Sciences (CAS).


GRB_name: GRB240112B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35521
SUBJECT: GRB 240112B: Fermi GBM Final Real-time Localization
DATE:    24/01/12 13:09:48 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 12:59:25 UT on 12 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240112B (trigger 726757170.415726 / 240112541).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 8.2, Dec = -65.9 (J2000 degrees, equivalent to J2000 00h 32m, -65d 54'), with a statistical uncertainty of 3.4 degrees.

The angle from the Fermi LAT boresight is 150.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112541/quicklook/glg_skymap_all_bn240112541.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112541/quicklook/glg_healpix_all_bn240112541.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112541/quicklook/glg_lc_medres34_bn240112541.gif


GRB_name: GRB240112C
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35522
SUBJECT: GRB 240112C: Swift detection of a burst with an optical counterpart
DATE:    24/01/12 17:51:21 GMT
FROM:    David Palmer at LANL <palmer@lanl.gov>


R. A. J. Eyles-Ferris (U Leicester), J.D. Gropp (PSU),
S. Laha (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), D. M. Palmer (LANL), M. H. Siegel (PSU) and
M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 17:37:24 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240112C (trigger=1208389).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 270.644, +24.487 which is 
   RA(J2000) = 18h 02m 35s
   Dec(J2000) = +24d 29' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  Due to a telemetry gap, the BAT lightcurve
is not immediately available. 

The XRT began observing the field at 17:39:18.9 UT, 114.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 270.64225, 24.48830 which is equivalent
to:
   RA(J2000)  = 18h 02m 34.14s
   Dec(J2000) = +24d 29' 17.9"
with an uncertainty of 4.7 arcseconds (radius, 90% containment). This
location is 7.4 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
https://www.swift.ac.uk/sper.  We cannot determine whether the source
is fading at the present time. No spectrum from the promptly downlinked
event data is yet available to determine the column density. 

UVOT took a finding chart exposure of 115 seconds with the White filter
starting 120 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 18:02:34.59 = 270.64414
  DEC(J2000) = +24:29:21.2  =  24.48923
with a 90%-confidence error radius of about 0.75 arc sec. This position is 7.4
arc sec. from the center of the XRT error circle. The estimated magnitude is
16.73 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.108. 

Burst Advocate for this burst is R. A. J. Eyles-Ferris (raje1 AT leicester.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240109A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35523
SUBJECT: GRB 240109A: Swift-BAT refined analysis
DATE:    24/01/12 18:37:07 GMT
FROM:    Sibasish Laha at GSFC <sibasish.laha@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), T. Parsotan (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-61 to T+242 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240109A (trigger #1207446)
(Dichiara et al., GCN Circ. 35501).  The BAT ground-calculated position is
RA, Dec = 301.330, 16.566 deg which is
   RA(J2000)  =  20h 05m 19.1s
   Dec(J2000) = +16d 33' 58.3"
with an uncertainty of 2.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.

The BAT  light curve shows a single peak with a duration ~0.5 sec.
T90 (15-350 keV) is 0.16 +- 0.06 sec (estimated error including systematics).

The time-averaged spectrum from T-0.04 to T+0.15 sec is better fit by a blackbody.
A simple power-law fit shows a photon index of 2.75 +-0.35 with a poor statistics (reduced chi2 of 1.9).
Instead, the black body fit shows the temperature of 12.2 +-1.3 keV
with a reasonable statistics (reduced chi2 of 1.2).  So, the burst
prefers a soft spectrum. The fluence in the 15-150 keV band is 1.2 +- 0.4 x 10^-08 erg/cm2.
The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band
is 0.7 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1207446/BA/


GRB_name: GRB240112B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35524
SUBJECT: Fermi GRB 240112B: Global MASTER-Net observations report
DATE:    24/01/12 19:46:24 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240112B ( Fermi GBM team, GCN 35521) errorbox  23429 sec after notice time and 23473 sec after trigger time at 2024-01-12 19:30:39 UT, with upper limit up to  19.2 mag. The observations began at zenith distance = 47 deg. The sun  altitude  is -18.7 deg. 

The galactic latitude b = -51 deg., longitude l = 306 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2354342

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   23504 | 2024-01-12 19:30:39 |         MASTER-SAAO | (00h 36m 58.81s , -65d 30m 24.0s) |   C |    60 | 19.2 |        
   23504 | 2024-01-12 19:30:39 |         MASTER-SAAO | (00h 30m 47.39s , -65d 17m 35.0s) |   C |    60 | 18.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240112C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35525
SUBJECT: Swift GRB 240112C: Global MASTER-Net observations report
DATE:    24/01/12 20:15:12 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Tunka robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the Swift GRB 240112C ( R. A. J. Eyles-Ferris et al., GCN 35522) errorbox  8981 sec after notice time and 9002 sec after trigger time at 2024-01-12 20:07:27 UT, with upper limit up to  15.4 mag. The observations began at zenith distance = 85 deg. The sun  altitude  is -45.5 deg. 

The galactic latitude b = 21 deg., longitude l = 51 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2354458

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    9040 |        MASTER-Tunka |   C |    75 | 12.4 |        
    9124 |        MASTER-Tunka |   C |    70 | 15.4 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240112D
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35527
SUBJECT: GRB 240112D: Fermi GBM Final Real-time Localization
DATE:    24/01/12 22:06:48 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 21:56:04 UT on 12 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240112D (trigger 726789369.452754 / 240112914).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 148.5, Dec = -79.4 (J2000 degrees, equivalent to J2000 09h 54m, -79d 24'), with a statistical uncertainty of 11.1 degrees.

The angle from the Fermi LAT boresight is 26.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112914/quicklook/glg_skymap_all_bn240112914.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112914/quicklook/glg_healpix_all_bn240112914.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112914/quicklook/glg_lc_medres34_bn240112914.gif


GRB_name: GRB240112D
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35528
SUBJECT: Fermi GRB 240112D: Global MASTER-Net observations report
DATE:    24/01/12 22:31:00 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240112D ( Fermi GBM team, GCN 35527) errorbox  42 sec after notice time and 78 sec after trigger time at 2024-01-12 21:57:23 UT, with upper limit up to  19.8 mag. The observations began at zenith distance = 52 deg. The sun  altitude  is -35.0 deg. 

The galactic latitude b = -20 deg., longitude l = 295 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2354610

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

      89 | 2024-01-12 21:57:23 |         MASTER-SAAO | (10h 37m 28.51s , -77d 28m 52.6s) |   C |    20 | 18.4 |        
     114 | 2024-01-12 21:57:23 |         MASTER-SAAO | (10h 37m 28.45s , -77d 28m 52.6s) |   C |    70 | 19.1 |  Coadd 
      89 | 2024-01-12 21:57:23 |         MASTER-SAAO | (10h 49m 36.14s , -77d 40m 50.9s) |   C |    20 | 18.6 |        
     114 | 2024-01-12 21:57:23 |         MASTER-SAAO | (10h 49m 36.14s , -77d 40m 50.8s) |   C |    70 | 19.5 |  Coadd 
     128 | 2024-01-12 21:58:02 |         MASTER-SAAO | (10h 37m 28.13s , -77d 28m 52.8s) |   C |    20 | 18.4 |        
     128 | 2024-01-12 21:58:02 |         MASTER-SAAO | (10h 49m 35.78s , -77d 40m 50.9s) |   C |    20 | 18.6 |        
     172 | 2024-01-12 21:58:41 |         MASTER-SAAO | (10h 37m 27.74s , -77d 28m 52.7s) |   C |    30 | 18.8 |        
     172 | 2024-01-12 21:58:41 |         MASTER-SAAO | (10h 49m 35.40s , -77d 40m 51.0s) |   C |    30 | 18.9 |        
     227 | 2024-01-12 21:59:31 |         MASTER-SAAO | (10h 37m 27.15s , -77d 28m 53.1s) |   C |    40 | 18.9 |        
     282 | 2024-01-12 21:59:31 |         MASTER-SAAO | (10h 37m 27.16s , -77d 28m 53.1s) |   C |   150 | 19.7 |  Coadd 
     227 | 2024-01-12 21:59:31 |         MASTER-SAAO | (10h 49m 34.89s , -77d 40m 51.0s) |   C |    40 | 19.2 |        
     282 | 2024-01-12 21:59:31 |         MASTER-SAAO | (10h 49m 34.90s , -77d 40m 51.1s) |   C |   150 | 19.8 |  Coadd 
     303 | 2024-01-12 22:00:42 |         MASTER-SAAO | (10h 37m 26.55s , -77d 28m 53.5s) |   C |    50 | 18.9 |        
     303 | 2024-01-12 22:00:42 |         MASTER-SAAO | (10h 49m 34.21s , -77d 40m 51.2s) |   C |    50 | 19.0 |        
     377 | 2024-01-12 22:01:51 |         MASTER-SAAO | (10h 37m 26.05s , -77d 28m 53.8s) |   C |    60 | 19.2 |        
     377 | 2024-01-12 22:01:51 |         MASTER-SAAO | (10h 49m 33.67s , -77d 40m 51.6s) |   C |    60 | 19.4 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240112E
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35529
SUBJECT: GRB 240112E: Fermi GBM Final Localization
DATE:    24/01/13 00:04:22 GMT
FROM:    Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

"At 17:48:07.46 UT on 12 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240112E (trigger 726774492/240112742).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 217.7, Dec = -32.6 (J2000 degrees, equivalent to J2000 14h 31m, -32d 35'),
with a statistical uncertainty of 3.4 degrees.

The angle from the Fermi LAT boresight is 125 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112742/quicklook/glg_skymap_all_bn240112742.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112742/quicklook/glg_healpix_all_bn240112742.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240112742/quicklook/glg_lc_medres34_bn240112742.gif"


GRB_name: GRB240112C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35530
SUBJECT: GRB 240112C: SAO RAS optical observations
DATE:    24/01/13 04:58:59 GMT
FROM:    Moskvitin Alexander at SAO RAS <mosk@sao.ru>

A. S. Moskvitin and O. A. Maslennikova (SAO RAS)
report on behalf of the GRB follow-up team.

We observed the field of Swift GRB 240112C (Eyles-Ferris et al.,
GCN #35522) with the 1-m telescope of SAO RAS equipped with the CCD
photometer. We obtained 21 x 60 sec. images in Rc band on January 13,
03:00:16--03:34:31 UT (t_mid - T0 = 0.40277 days) under mediocre
weather conditions.

We did not detect any significant source at the OT position
down to the limiting magnitude R_lim = 21.1
(based on R2 magnitudes of nearby USNO-B1 stars).


GRB_name: GRB240112C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35531
SUBJECT: GRB 240112C: Swift-XRT refined Analysis
DATE:    24/01/13 10:19:51 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P. D'Avanzo
(INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi  (INAF-IASFPA) ,
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU) and
P.A. Evans report on behalf of the Swift-XRT team:

We have analysed 6.3 ks of XRT data for GRB 240112C, from 97 s to 45.8
ks after the  BAT trigger. The data comprise 39 s in Windowed Timing
(WT) mode (the first 10 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. Using 2660 s of PC mode data
and 6 UVOT images, we find an enhanced XRT position (using the XRT-UVOT
alignment and matching UVOT field sources to the USNO-B1 catalogue):
RA, Dec = 270.64402, +24.48893 which is equivalent to:

RA (J2000): 18h 02m 34.56s
Dec(J2000): +24d 29' 20.2"

with an uncertainty of 2.0 arcsec (radius, 90% confidence).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.61 (+0.04, -0.48), followed by a break at T+5970 s to
an alpha of 1.30 (+0.18, -0.20).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.92 (+0.14, -0.13). The
best-fitting absorption column is  2.0 (+0.5, -0.4) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.6 x 10^-11 (4.8 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.0 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: 2.5 sigma
Photon index:      1.92 (+0.14, -0.13)

If the light curve continues to decay with a power-law decay index of
1.30, the count rate at T+24 hours will be 0.015 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.3 x
10^-13 (7.0 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01208389.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240112C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35533
SUBJECT: GRB 240112C: Fermi GBM Detection
DATE:    24/01/13 16:09:48 GMT
FROM:    Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>

P. Veres (UAH), R. Hamburg (CNRS/IN2P3), A. Myers (NPP/GSFC) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 17:37:25.12 UT on 12 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240112C (trigger 726773850/240112734). GRB 240112C 
was also localized by Swift BAT and XRT (Eyles-Ferris et al., GCN #35522).
The Fermi GBM on-ground Localization is consistent with the Swift position.


The angle from the Fermi LAT boresight is 43 degrees.

The GBM light curve consists of two pulses with a duration (T90)
of about 5.3 s (50-300 keV). The time-averaged spectrum
from T0-0.6 to T0+6.3 s is best fit by
a Band function with with Epeak= 71 +/- 6 keV, alpha = -1.26 +/- 0.08 
and beta = -2.34 +/- 0.10.


The event fluence (10-1000 keV) in this time interval is
(4.8 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band is 20.2 +/- 0.4 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240112C
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35534
SUBJECT: GRB 240112C: Swift/UVOT Detection
DATE:    24/01/14 18:22:22 GMT
FROM:    Paul Kuin at MSSL <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and Eyles-Ferris (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240112C
121 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 35522).
A source consistent with the XRT position is detected in the initial
UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  18:02:34.58 = 270.64410 (deg.)
    Dec (J2000) = +24:29:21.3  =  24.48925 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric
system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              121          236          113         16.98 +/- 0.04
v                 4955         5126          169        >18.6
b                 4340         4539          197         19.35 +/- 0.16
u                 4134         4334          197         19.11 +/- 0.18
w1                3930         4129          197         19.13 +/- 0.24

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.108 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240114A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35535
SUBJECT: GRB 240114A: MAXI/GSC detection
DATE:    24/01/15 00:53:26 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

T. Kawamuro (RIKEN), M. Serino (AGU), 
H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.), 
T. Mihara, S. Yamada, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), 
T. Sakamoto, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), 
Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto, E.Goto (Chuo U.), 
M. Shidatsu, Y. Niida (Ehime U.),
I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech), 
S. Nakahira,  S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA), 
Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.), 
M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.), 
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
M. Sugizaki (NAOC),
W. Iwakiri (Chiba U.) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source 
at 14:28:50 UT on January 14, 2024.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (78.966 deg, 33.742 deg) = (05 15 51, +33 44 31) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.28 deg and 0.25 deg, respectively.
The roll angle of long axis from the north direction is 159.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 145 +- 21 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
 (77.740, 33.819) deg = (05 10 57, +33 49 08) (J2000) 
 (77.869, 33.281) deg = (05 11 28, +33 16 51) (J2000) 
 (80.079, 33.628) deg = (05 20 18, +33 37 40) (J2000) 
 (79.963, 34.167) deg = (05 19 51, +34 10 01) (J2000). 
There was no significant excess flux in the previous transit at 12:55 UT
and in the next transit at 16:01 UT with an upper limit of 20 mCrab for each.


GRB_name: GRB240112C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35545
SUBJECT: GRB 240112C: VZLUSAT-2 detection
DATE:    24/01/16 16:05:00 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory),  N. Werner  (Masaryk U.), M. Ohno (Hiroshima U.),  L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU)  -- the VZLUSAT-2/GRB payload collaboration.

The long-duration GRB 240112C (Swift/BAT detection: GCN 35522; Fermi/GBM detection: GCN 35533; GRBAlpha detection: GCN 35536; Konus/Wind detection: GCN 35539; INTEGRAL/SPI-ACS detection: trigger no. 10466) was detected by the GRB detector on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).

The data acquisition was performed by the GRB detector unit no. 1. The detection was confirmed at the peak time 2024-01-12 17:37:27 UTC. The T90 duration is 3 s and the significance during T90 reaches 14 sigma.

The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB240112C_GCN_VZLUSAT2.pdf

All VZLUSAT-2 detections are listed at: https://monoceros.physics.muni.cz/hea/VZLUSAT-2/
The GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral.


GRB_name: GRB240112C
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35546
SUBJECT: GRB 240112C: Glowbug gamma-ray detection
DATE:    24/01/16 17:32:02 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J. E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge (MSFC), and M.S. Briggs (UAH) report:                                                                                                                                                                                                                                                   
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240112C, which was also detected by Swift/BAT, Fermi/GBM, GRBAlpha, Konus-Wind, VZLUSAT-2 (GCN #35522, #35533, #35536, #35539, #35545), and INTEGRAL/SPI-ACS (Trigger no. 10466).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-12 17:37:23.592 with a duration of 4.10 s and a total significance of about 20.1 sigma.  The light curve comprises two primary peaks.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.6 and a cutoff energy ("Epeak") of 185 keV.  The modeled 10-10000 keV fluence is 7.5e-07 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240112D
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35547
SUBJECT: GRB 240112D: Glowbug gamma-ray detection
DATE:    24/01/16 17:32:58 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J. E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge (MSFC), and M.S. Briggs (UAH) report:                                                                                                                                                                                                                                                   
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240112D, which was also detected by Fermi/GBM (GCN #35527) and INTEGRAL/SPI-ACS (Trigger no. 10468).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-12 21:56:04.064 with a duration of 2.56 s and a total significance of about 13.0 sigma.  The light curve comprises a single peak.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.5 and a cutoff energy ("Epeak") of 455 keV.  The modeled 10-10000 keV fluence is 1.3e-06 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240115B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35549
SUBJECT: GRB 240115B: Fermi GBM Detection
DATE:    24/01/16 20:10:53 GMT
FROM:    sumanbala2210@gmail.com

R. Hamburg (CNRS/IN2P3), S. Bala (USRA), and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 16:45:37.62 UT on 15 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240115B (trigger 727029942/240115698). GRB 240115B
was also localized by INTEGRAL (S. Mereghetti et al. 2024, GCN 35541).

The angle from the Fermi LAT boresight is 97 degrees.

The GBM light curve consists of multiple peaks of emission
with a duration (T90) of about 163 s (50-300 keV). 
The time-averaged spectrum from T0-26.63 s to T0+47.11 s 
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.73 +/- 0.11,
and the cutoff energy parameterized as Epeak, is 125 +/- 10.

The event fluence (10-1000 keV) in this time interval is
(5.13 +/- 0.26)E-06 erg/cm^2. The 1-sec peak photon flux measured
 starting from T0+17.6 s in the 10-1000 keV band is 2.6 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240115B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35551
SUBJECT: GRB 240115B: AstroSat CZTI detection
DATE:    24/01/17 07:19:29 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240115B which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35540), and INTEGRAL (S.Mereghetti et al., GCN Circ. 35541).

The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-01-15 16:45:40.50 UTC. The measured peak count rate associated with the burst is 80 (+42, -5) counts/s above the background in the combined data of three quadrants (out of four), with a total of 2052 (+489, -339) counts. The local mean background count rate was 280 (+1, -4) counts/s. Using cumulative rates, we measure a T90 of 47 (+7, -4) s. 

The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-01-15 16:46:04.75 UTC. The measured peak count rate associated with the burst is 127 (+72, -1) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1941 (+685, -748) counts. The local mean background count rate was 1168 (+5, -5) counts/s. We measure a T90 of 36 (+6, -10) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240115A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35557
SUBJECT: GRB 240115A: Swift/BAT-GUANO detection of a short burst
DATE:    24/01/17 21:20:29 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:

Swift/BAT did not localize GRB 240115A onboard (T0: 2024-01-15T11:03:14.11 UTC, Fermi GBM Trig 727009399, INTEGRAL SPI-ACS Trig 10471). 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 7.5 in a 1.024 s analysis time bin, starting at T0 - 0.256 s. 

NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 5.4.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240118A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35558
SUBJECT: GRB 240118A: Fermi GBM Final Real-time Localization
DATE:    24/01/18 01:58:38 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 01:48:09 UT on 18 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240118A (trigger 727235294.440514 / 240118075).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 14.1, Dec = 30.9 (J2000 degrees, equivalent to J2000 00h 56m, 30d 53'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 63.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240118075/quicklook/glg_skymap_all_bn240118075.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240118075/quicklook/glg_healpix_all_bn240118075.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240118075/quicklook/glg_lc_medres34_bn240118075.gif


GRB_name: GRB231230A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35559
SUBJECT: GRID detection of GRB 231230A
DATE:    24/01/18 04:50:00 GMT
FROM:    GRID Student Team at Tsinghua University <grid@tsinghua.edu.cn>

Chenyu Wang, Zirui Yang and Longhao Li report on behalf of the GRID Collaboration:

GRID-04 reports the detection of the long-duration GRB 231230A, which was also detected by Swift/BAT and Fermi/GBM(GCN Circular 35434 and 35436).

The event was triggered with GRID on 2023-12-30 at 01:29:08â€‹ UTC. The GRID light curve consists of multiple spikes with a duration (T90) of about 17 +/- 1 s (30-2000 keV).
The time-averaged spectrum from T0+0.4 to T0+17.3 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.03 +/- 0.2 and the cutoff energy, parameterized as Epeak, is 132 +/- 45 keV. The event fluence (10-1000 keV) in this time interval is about 6.0E-06 erg/cm^2.â€‹

The GRID light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB231230A/GRID_231230A_ltcv.pdf. The GRID spectrum of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB231230A/GRID_231230A_spec_cpl.pdf.

GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to the following references: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4.â€‹â€‹


GRB_name: GRB240118A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35560
SUBJECT: GRB 240118A: Fermi-LAT detection
DATE:    24/01/18 09:58:01 GMT
FROM:    Elisabetta Bissaldi at Politecnico and INFN Bari <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari), F. Longo (University and INFN Trieste)
and Makoto Arimoto (Kanazawa University) report on behalf of the Fermi-LAT Collaboration:


At 01:48:09.44 on January, 18, 2024 Fermi-LAT detected high-energy emission
from GRB 240118A, which was also detected by Fermi-GBM (trigger 727235294 / 240118075, 
GCN #35558).

The best LAT on-ground location is found to be

RA, Dec = 18.57, 29.79 (J2000)

with an error radius of 0.05 deg (90 % containment, statistical error only).
This was 69 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the trigger with high significance.
The photon flux above 100 MeV in the time interval 0-2000 s
after the GBM trigger time is (7.3 +/- 1.0)E-6 ph/cm2/s.
The estimated photon index above 100 MeV is -1.9 +/- 0.1.
The highest-energy photon is a 41 GeV event, which is observed 
732 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

The Fermi-LAT point of contact for this burst is 
Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it).

The Fermi-LAT is a pair conversion telescope designed to cover
the energy band from 20 MeV to greater than 300 GeV.
It is the product of an international collaboration between
NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden.


GRB_name: GRB240118B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35562
SUBJECT: GRB 240118B: Fermi GBM Final Real-time Localization
DATE:    24/01/18 12:21:43 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 12:11:05 UT on 18 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240118B (trigger 727272670.288166 / 240118508).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 49.8, Dec = -55.0 (J2000 degrees, equivalent to J2000 03h 19m, -55d 00'), with a statistical uncertainty of 7.1 degrees.

The angle from the Fermi LAT boresight is 44.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240118508/quicklook/glg_skymap_all_bn240118508.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240118508/quicklook/glg_healpix_all_bn240118508.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240118508/quicklook/glg_lc_medres34_bn240118508.gif


GRB_name: GRB240118A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35563
SUBJECT: GRB 240118A: Fermi GBM Observation
DATE:    24/01/18 16:07:47 GMT
FROM:    rachel.hamburg@ijclab.in2p3.fr

R. Hamburg (CNRS/IN2P3), S. Dalessi (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 01:48:09.44 UT on 18 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240118A (trigger 727235294/240118075),
which was also detected by Fermi-LAT (Bissaldi et al. 2024, GCN 35560).
The Fermi GBM on-ground location (GCN 35558) is consistent with the Fermi-LAT position.

The angle from the Fermi LAT boresight is 64 degrees.

The GBM light curve consists of multiple bright pulses with a duration (T90)
of about 54 s (50-300 keV). The time-averaged spectrum
from T0+0 s to T0+150 s is best fit by 
a Band function with Epeak = 374 +/- 3 keV,
alpha = -0.71 +/- 0.004, and beta = -2.35 +/- 0.02.

The event fluence (10-1000 keV) in this time interval is
(5.81 +/- 0.01)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+72.5 s in the 10-1000 keV band is 94.6 +/- 0.5 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240118A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35564
SUBJECT: GRB 240118A: NuSTAR Detection of a Long GRB
DATE:    24/01/18 17:14:54 GMT
FROM:    Brian Grefenstette at Caltech/NuSTAR <bwgref@srl.caltech.edu>

B. Grefenstette on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group:

The NuSTAR SINGS working group reports the detection of prompt emission of the GRB 240118A in the NuSTAR CsI anti-coincidence shields. Thus GRB was identified through a blind search using the CsI shield rates with a trigger time (2024-01-18 01:48:46). This is consistent with the time of the delayed large peak seen in the GBM lightcurve from Fermi GBM (Fermi Team GCN 35558, Hamburg GCN 35563) which arrives ~40-sec after the initial GBM trigger at 01:48:09. Data from the CdZnTe detectors have not yet been downloaded from the spacecraft.

The burst shows at least three broad peaks in the CsI shields from both NuSTAR FPMs, peaking at 3000-5000 counts per second (the background in the shields was roughly 1000 cps).

The automated light curve report for this GRB and discovery report can be found here:

https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2024/240118A/

â€¦where further offline analysis will be performed once more data are downloaded from NuSTAR.


GRB_name: GRB240118C
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35565
SUBJECT: GRB 240118C: BALROG localization (Fermi Trigger 727291408 / GRB 240118725)
DATE:    24/01/18 17:59:26 GMT
FROM:    Jochen Greiner at MPE <jcgrog@mpe.mpg.de>

T. Preis, B. Biltzinger, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
727291408 at 17:23:23 on 18 Jan. 2024 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position is:
RA(2000.0) = 305.3 deg
Decl.(2000.0) = -9.8 deg
The 1 sigma statistical error radius is 1.6 deg.
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB240118725/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB240118725/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB240118725/json

                        


GRB_name: GRB240118A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35567
SUBJECT: Konus-Wind detection of GRB 240118A
DATE:    24/01/18 18:44:56 GMT
FROM:    Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>

D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long, very bright GRB 240118A
(Fermi GBM observation: Hamburg et al., GCN 35563;
Fermi LAT detection: Bissaldi et al., GCN 35560;
NuSTAR detection: Grefenstette, GCN 35564)
triggered Konus-Wind (KW) at T0=6508.107 s UT (01:48:28.107).

The burst light curve shows a multi-peaked structure,
which starts at ~T0-2.4 s, peaks at ~T0+37.5 s,
and has a total duration of ~90 s.
The emission is seen up to ~15 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240118_T06508/

As observed by Konus-Wind, the burst had
a fluence of (8.24 Â± 0.38)x10^-4 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 37.568 s,
of (6.65 Â± 0.63)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+90.880 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.69 (-0.03,+0.03),
the high energy photon index beta = -2.37 (-0.05,+0.05),
the peak energy Ep = 402 (-12,+13) keV,
chi2 = 167/97 dof.

The spectrum near the peak count rate (measured from T0+36.352 s to T0+38.144 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.61 (-0.06,+0.07),
the high energy photon index beta = -2.62 (-0.21,+0.15),
the peak energy Ep = 634 (-51,+55) keV,
chi2 = 74/66 dof.

All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.


GRB_name: GRB240118A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35568
SUBJECT: GRB 240118A: Swift/BAT-GUANO detection of a burst outside the coded FOV 
DATE:    24/01/18 21:03:45 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: 

Swift/BAT did not localize GRB 240118A onboard (T0: 2024-01-18T01:48:09.44 UTC, Fermi trig 727235294, Konus-Wind GCN 35567, NuSTAR GCN 35564) 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. 

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0+32 s, T0+72 s] (centered around the peak count rate), detects the burst with a sqrt(TS) of 125.5 in a 16.384 s analysis time bin, starting at T0 + 43.808. 

NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of -930.9.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. 

GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. 

A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240117A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35569
SUBJECT: GRB 240117A: Glowbug gamma-ray detection
DATE:    24/01/18 21:30:43 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J.E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240117A, which was also detected by CALET/CGBM (Trigger 1389556167) and INTEGRAL/SPI-ACS (Trigger 10476).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-17 19:52:29.928 with a duration of 9.2 s and a total significance of about 35.3 sigma.  The light curve comprises two primary peaks.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.9 and a cutoff energy ("Epeak") of 264 keV.  The modeled 10-10000 keV fluence is 3.8e-06 erg/cm^2.
 
The best-fit localization is RA, Decl. (J2000, deg) = 229.6, 3.1 with a radius of 18.7 deg (95% confidence), with a highly uncertain systematic uncertainty.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240118A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35570
SUBJECT: GRB 240118A: NuSTAR Offline Analysis of the GRB
DATE:    24/01/18 21:58:42 GMT
FROM:    Brian Grefenstette at Caltech/NuSTAR <bwgref@srl.caltech.edu>

B. Grefenstette on behalf of the NuSTAR Search for INteresting Gamma-ray Signals (SINGS) working group:

The NuSTAR SINGS working group has performed additional offline analysis of the GRB 240118A detected by Fermi (Hamburg, GCN 35563), Swift BAT (DeLaunay, GCN 35568), and Konus-Wind (Frederiks, GCN 35567). Using the localization from the Fermi LAT (Bissaldi, GCN 35560) we estimate that the GRB was only ~12-degrees from the telescope boresight at 2024-01-18T01:48:09.

The CsI shields do not clearly detect the precursor event that triggered the GBM at 2024-01-18T01:48:09. However, there are multiple strong peaks ~40-sec later. We have updated the automated GRB report to include the recently downloaded X-ray data here:

https://nustarsoc.caltech.edu/NuSTAR_Public/grbs/reports/2024/240118A/

This includes enhanced light curves showing 1-Hz CsI anticoincidence shield data as well as the CdZnTe X-ray data binned at 2-s intervals. The shield data clearly resolves the GRB into at least three main peaks with significant substructure. All three peaks are also seen in the X-ray detectors, with excess counts that extend up to at least 200 keV.

However, the response files of the detectors is complicated due to the intervening material so detailed spectroscopic analysis of the individual bursts cannot be performed at this time.


GRB_name: GRB240118B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35571
SUBJECT: Fermi GRB 240118B: Global MASTER-Net observations report
DATE:    24/01/19 00:31:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240118B ( Fermi GBM team, GCN 35562) errorbox  43321 sec after notice time and 43354 sec after trigger time at 2024-01-19 00:13:40 UT, with upper limit up to  18.5 mag. The observations began at zenith distance = 65 deg. The sun  altitude  is -33.7 deg. 

The galactic latitude b = -51 deg., longitude l = 269 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2359396

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   43385 | 2024-01-19 00:13:40 |         MASTER-SAAO | (03h 19m 56.04s , -54d 00m 56.6s) |   C |    60 | 18.4 |        
   43476 | 2024-01-19 00:15:11 |         MASTER-SAAO | (03h 30m 18.84s , -53d 48m 55.0s) |   C |    60 | 18.3 |        
   43476 | 2024-01-19 00:15:11 |         MASTER-SAAO | (03h 33m 26.11s , -54d 01m 50.8s) |   C |    60 | 18.1 |        
   43556 | 2024-01-19 00:16:31 |         MASTER-SAAO | (03h 06m 29.36s , -55d 42m 49.0s) |   C |    60 | 18.5 |        
   43556 | 2024-01-19 00:16:31 |         MASTER-SAAO | (03h 09m 45.21s , -55d 55m 46.4s) |   C |    60 | 18.5 |        
   43636 | 2024-01-19 00:17:51 |         MASTER-SAAO | (03h 33m 30.51s , -55d 40m 53.5s) |   C |    60 | 18.1 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240118A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35572
SUBJECT: GRB 240118A: AbAO optical upper limit
DATE:    24/01/19 01:25:42 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), S. Belkin (IKI) report on behalf of IKI GRB FuN:

We observed the field of  Fermi LAt localization of GRB 240118A (Bissaldi, GCN 35560)  and detected also Fermi GBM (Fermi GBM team, GCN 35558; Hamburg, GCN 35563), NuSTAR (Grefenstette, GCN 35564), Swift BAT (DeLaunay, GCN 35568), and Konus-Wind (Frederiks, GCN 35567)  with AS-32 telescope of Abastumani observatory (AbAO) in R-filter starting on  2024-01-18 (UT) 16:47:55. No optical candidate is detected in the LAT localization area (Bissaldi, GCN 35560). Preliminary photometry of the filed is following

Date       UT start   t-T0    Filter Exp.    OT     Err.  UL(3sigma)
                       (mid, days)    (s)

2024-01-18 16:47:55  0.625069  R     40*60   n/d    n/d   17.4

The photometry is based on nearby USNO-B1.0 stars.


GRB_name: GRB240118A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35573
SUBJECT: GRB 240118A: Swift ToO observations
DATE:    24/01/19 04:29:59 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a ToO observation of the Fermi/LAT GRB 240118A. 
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021644

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a 
GCN Circular after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240117A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35574
SUBJECT: GRB 240117A: AstroSat CZTI detection
DATE:    24/01/19 04:56:39 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240117A which was also detected by Calet (Trigger Num. 1389556167), Integral-SPIACS (Trigger Num. 10476), and Glowbug (Cheung et al., GCN Circ. 35569).

The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-17 19:52:36.50 UTC. The measured peak count rate associated with the burst is 156 (+35, -30) counts/s above the background in the combined data of three quadrants (out of four), with a total of 451 (+136, -161) counts. The local mean background count rate was 292 (+4, -3) counts/s. Using cumulative rates, we measure a T90 of 3.62 (+3.5, -1.6) s.

The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-17 19:52:35.72 UTC. The measured peak count rate associated with the burst is 208 (+80, -23) counts/s above the background in the combined data of three quadrants (out of four), with a total of 937 (+206, -219) counts. The local mean background count rate was 1475 (+7, -8) counts/s. We measure a T90 of 5.13 (+0.54, -1.39) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240118D
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35575
SUBJECT: GRB 240118D: AstroSat CZTI detection
DATE:    24/01/19 06:44:00 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240118D which was also detected by INTEGRAL-SPI-ACS (Trigger Num. 10478).

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-18 07:48:13.55 UTC. The measured peak count rate associated with the burst is 351 (+165, -33) counts/s above the background in the combined data of all quadrants, with a total of 584 (+142, -136) counts. The local mean background count rate was 323 (+7, -10) counts/s. Using cumulative rates, we measure a T90 of 4 (+1, -1) s. We also see a faint second extended peak, consistent with the light curve from INTEGRAL-SPI-ACS, which is more prominently seen in the Veto detectors as reported below.

The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-01-18 07:48:12.73 UTC. The measured peak count rate associated with the burst is 1088 (+90, -49) counts/s above the background in the combined data of all quadrants, with a total of 5639 (+649, -701) counts. The local mean background count rate was 1402 (+6, -7) counts/s. We measure a T90 of 30 (+7, -4) s from the cumulative Veto light curve. 

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb 


GRB_name: GRB240115A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35578
SUBJECT: GRB 240115A: Fermi GBM Observation
DATE:    24/01/19 15:36:32 GMT
FROM:    rachel.hamburg@ijclab.in2p3.fr

R. Hamburg (CNRS/IN2P3) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 11:03:14.11 UT on 15 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240115A (trigger 727009399/240115461),
which was also detected by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 35557).
The Fermi Final Real-time Localization is reported in GCN 35537.

The angle from the Fermi LAT boresight is 37 degrees.

The GBM light curve consists of one main pulse with a duration (T90)
of about 1.79 s (50-300 keV). The time-averaged spectrum
from T0-0.26 to T0+0.77 s is best fit by a power law function 
with an exponential high-energy cutoff.
The power law index is -0.7 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 450 +/- 137 keV.

The event fluence (10-1000 keV) in this time interval is
(4.8 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.64 s in the 10-1000 keV band is 3.4 +/- 1.0 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240118A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35580
SUBJECT: GRB 240118A: GRBAlpha detection
DATE:    24/01/19 17:40:49 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The bright long-duration GRB 240118A (Fermi/GBM detection: GCN 35558; Fermi/LAT detection: GCN 35560; NuSTAR detection: GCN 35564; Konus/Wind detection: GCN 35567; Swift/BAT detection: GCN 35522; INTEGRAL/SPI-ACS detection: trigger no. 10477) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-01-18 01:49:22 UTC. The T90 duration measured by GRBAlpha is 58 s and the overall significance during T90 reaches 174 sigma.

The light curve shows a multiple-peaked structure which is consistent with light curves observed by other missions. However, GRBAlpha was passing through the van Allen radiation belt during the entire burst duration and therefore the measured count rate is subject to a higher variable background which cannot be distinguished from the burst itself.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240118A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240118C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35581
SUBJECT: GRB 240118C: Swift/BAT-GUANO detection of a burst
DATE:    24/01/19 18:12:06 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:

Swift/BAT did not localize GRB 240118C onboard (T0: 2024-01-18T17:23:23.93 UTC, Fermi GBM Trig 727291408, INTEGRAL SPI-ACS Trig 10480). 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 10.2 in a 16.384 s analysis time bin, starting at T0 + 12.288 s. 

NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 9.6.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240117A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35582
SUBJECT: GRB 240117A: CALET Gamma-Ray Burst Monitor detection
DATE:    24/01/19 18:53:39 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

M. L. Cherry (LSU) A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 240117A (Glowbug gamma-ray detection: Cheung
et al., GCN Circ 35569; AstroSat CZTI detection: Joshi et al., GCN
Circ 35574) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 19:52:31.44 UTC on 17 January 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1389556167/).
The burst signal was seen by only the SGM detector.

The burst light curve shows a single pulse that starts at T+2.4 sec, 
peaks at T+4.5 sec, and ends at T+8.8 sec. The T90 and T50 durations
measured by the SGM data are 5.7 +/- 0.6 sec and 2.6 +/- 0.3 sec 
(40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1389556167/index.html

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB240119A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35583
SUBJECT: GRB 240119A: Fermi GBM Final Localization
DATE:    24/01/19 21:51:28 GMT
FROM:    Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov>

"The Fermi GBM team reports the detection of a likely SHORT GRB:

At 17:29:07.68 UT on 19 January 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240119A (trigger 727378152/240119729).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 152.7, Dec = -83.6 (J2000 degrees, equivalent to J2000 10h 10m, 83d 36'), with a statistical uncertainty of 5.1 degrees.
 
The angle from the Fermi LAT boresight is 153.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240119729/quicklook/glg_skymap_all_bn240119729.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240119729/quicklook/glg_healpix_all_bn240119729.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240119729/quicklook/glg_lc_medres34_bn240119729.gif."


GRB_name: GRB240119A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35585
SUBJECT: Fermi GRB 240119A: Global MASTER-Net observations report
DATE:    24/01/20 00:46:03 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240119A ( "The Fermi GBM team, GCN 35583) errorbox  24476 sec after notice time and 24484 sec after trigger time at 2024-01-20 00:17:12 UT, with upper limit up to  19.8 mag. The observations began at zenith distance = 52 deg. The sun  altitude  is -33.6 deg. 

The galactic latitude b = -22 deg., longitude l = 299 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2360174

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   24514 | 2024-01-20 00:17:12 |         MASTER-SAAO | (10h 07m 17.25s , -84d 10m 49.7s) |   C |    60 | 19.6 |        
   24514 | 2024-01-20 00:17:12 |         MASTER-SAAO | (10h 25m 18.35s , -84d 23m 42.8s) |   C |    60 | 19.5 |        
   24594 | 2024-01-20 00:18:31 |         MASTER-SAAO | (09h 30m 35.62s , -82d 17m 59.7s) |   C |    60 | 19.7 |        
   24594 | 2024-01-20 00:18:31 |         MASTER-SAAO | (09h 44m 15.29s , -82d 30m 47.6s) |   C |    60 | 19.5 |        
   24674 | 2024-01-20 00:19:51 |         MASTER-SAAO | (11h 24m 48.94s , -82d 18m 00.4s) |   C |    60 | 19.8 |        
   24674 | 2024-01-20 00:19:51 |         MASTER-SAAO | (11h 38m 19.63s , -82d 31m 09.3s) |   C |    60 | 19.6 |        
   24753 | 2024-01-20 00:21:10 |         MASTER-SAAO | (11h 21m 22.33s , -86d 04m 09.3s) |   C |    60 | 19.6 |        
   24753 | 2024-01-20 00:21:10 |         MASTER-SAAO | (11h 48m 01.32s , -86d 17m 30.3s) |   C |    60 | 19.6 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240118C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35586
SUBJECT: GRB 240118C: Fermi GBM Observation
DATE:    24/01/20 01:01:56 GMT
FROM:    Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma@nasa.gov>

V. Sharma (NASA-GSFC/UMBC) and C. Meegan (UAH) report on behalf of the 
Fermi Gamma-ray Burst Monitor Team:

"At 17:23:23.93 UT on 18 January 2024, the Fermi Gamma-ray Burst Monitor (GBM) 
triggered and located GRB 240118C (trigger 727291408/240118725), which was also 
detected by Swift/BAT-GUANO (DeLaunay et al. 2024, GCN 35581).
The Fermi Final Real-time Localization is reported in GCN 35576.

The angle from the Fermi LAT boresight is 90 degrees.

The GBM light curve consists of multiple pulses with a duration (T90)
of about 31 s (50-300 keV). The time-averaged spectrum from 
T0-0.6 to T0+32.5 s is best fit by a power law function with 
an exponential high-energy cutoff.
The power law index is -1.39 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 144 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval is (1.23 +/- 0.04)E-05 erg/cm^2. 
The 1-sec peak photon flux measured starting from T0+29.7 s in the 10-1000 keV band 
is 13.6 +/- 0.5 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/."


GRB_name: GRB240118A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35588
SUBJECT: GRB 240118A: Mondy optical observations
DATE:    24/01/20 23:54:29 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of IKI GRB FuN:

We observed the field of  Fermi LAT localization of GRB 240118A (Bissaldi, GCN 35560), which was also detected by Fermi GBM (Fermi GBM team, GCN 35558; Hamburg, GCN 35563), NuSTAR (Grefenstette, GCN 35564), Konus-Wind (Frederiks, GCN 35567), Swift BAT (DeLaunay, GCN 35568), and GRBAlpha (Dafcikova et al., GCN 35580), and the localization area  observed by MASTER-Tunka observatory (Lipunov et al., GCN 35561) and Abastumani observatory (Pankov et al., GCN 35572).

Observations  started on  2024-01-18 (UT) 14:13:46 with AZT-33IK  telescope of Sayan observatory (Mondy) in the R-filter. The observations have been carried out in moderate weather conditions with FWHM of 2.5". We report observations of XRT candidates detected in the Swift TOO program (Evans et al., GCN 35573).
XRT #1 - out of FOV
XRT #2 - matches bright USNO-B1.0 star with R2=9.98 mag
XRT #3 - within the XRT #3 error circle we detect a faint source, which matches SDSS J011408.49+294753.1 source with SDSS DR12 r'= 22.117 and redshift of z_phot = 0.68
XRT #4 - out of FOV
XRT #5 - matches bright Gaia DR3 star with G=6.48 mag
XRT #6 - out of FOV
XRT #7 - out of FOV

Preliminary photometry of the faint source XRT #3 suggested as an X-ray afterglow (Beardmore et al., GCN  35587) is following

Date       UT start   t-T0    Filter Exp.    OT     Err.  UL(3sigma)
                       (mid, days)    (s)

2024-01-18 14:13:46  0.537932  R     29*120   22.1   0.3   22.1

The photometry is based on nearby USNO-B1.0 stars. 

At this time we cannot say anything about the variability of the source. The source at coordinates 01:14:08.48 +29:47:53.2, spatially coinciding with the galaxy SDSS J011408.49+294753.1 with a redshift of 0.68 could be a host galaxy of GRB 240118A.


GRB_name: GRB240119A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35589
SUBJECT: GRB 240119A: AstroSat CZTI detection of a short burst
DATE:    24/01/21 06:57:24 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a short-duration GRB 240119A which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35583).

The source was detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-19 17:29:07.67 UTC. The measured peak count rate associated with the burst is 1304 (+583, -314) counts/s above the background in the combined data of three quadrants (out of four), with a total of 53 (+17, -18) counts. The local mean background count rate was 250 (+25, -36) counts/s. Using cumulative rates, we measure a T90 of 0.06 (+0.02, -0.03) s.

The source was also faintly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range but we cannot make quantitative inferences due to the intrinsic 1 s binning of Veto data.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240118C
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35590
SUBJECT: GRB 240118C: GECAM-B detection of a long burst 
DATE:    24/01/21 07:39:21 GMT
FROM:    wenlongzhang2018@163.com

Wen-Long Zhang, Shao-Lin Xiong, Yan-Qiu Zhang report on behalf of the GECAM team:

GECAM-B was triggered on-ground by a long burst, GRB 240118C, at 2024-01-18T17:23:24.000 UTC (T0), which was also observed by Fermi/GBM (GCN #35576 and GCN #35586) and Swift/BAT-GUANOï¼ˆGCN #35581ï¼‰. 

According to the GECAM-B light curve, this burst consists of  roughly three pulses with a total duration of ~40 sec. 

The GECAM-B ground calculated location (J2000) is:
Ra: 308.64 deg   
Dec: -1.56 deg
Err: 4.65 deg (1-sigma, statistical only)
This GECAM-B localization is consistent with that of Fermi/GBM within the error.

We note that these results are very preliminary. Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).


GRB_name: GRB240119A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35591
SUBJECT: GRB 240119A: GECAM detection of a short burst 
DATE:    24/01/21 07:42:30 GMT
FROM:    wenlongzhang2018@163.com

Wen-Long Zhang, Shao-Lin Xiong, Chen-Wei Wang, Yue Wang, Yan-Qiu Zhang report on behalf of the GECAM team:

GECAM-B was triggered in-flight by a short burst, GRB 240119A, at 2024-01-19T17:29:07.700 UTC (T0), which was also detected by Fermi/GBM (GCN #35583) and AstroSat CZTI (GCN #35589). At the same time, GECAM-C was also triggered on-ground by this burst. 

According to the light curves, this burst shows a total duration of ~0.1 sec (20-1000 keV). 

According to the in-flight software, GECAM-B localized this burst to the following position (J2000): 
Ra: 355.51 deg   
Dec: -81.39 deg
Err: 5.76 deg (1-sigma, statistical only)
This GECAM-B localization is consistent with that of Fermi/GBM within the error.

We note that these results are very preliminary. Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).


GRB_name: GRB240119A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35594
SUBJECT: Konus-Wind detection of GRB 240119A (short/hard)
DATE:    24/01/22 15:40:27 GMT
FROM:    Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>

D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short GRB 240119A (Fermi-GBM detection: The Fermi GBM team, GCN 35583;
AstroSat-CZTI detection: Joshi et al.: GCN 35589;
GECAM-B detection: Zhang et al.: GCN 355921;
IPN triangulation: Svinkin et al., GCN 35592)
triggered Konus-Wind (KW) at T0=62945.465 s UT (17:29:05.465).

The burst light curve shows a single emission pulse
which starts at ~T0-0.032 s and has a duration of ~0.13 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240119_T62945/

As observed by Konus-Wind, the burst had
a total fluence of (8.1 Â± 1.7)x10^-7 erg/cm^2 and
a 16-ms peak energy flux, measured from T0-0.016 s,
of (1.9 Â± 0.4)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured from T0-0.048 s to T0+0.080 s)
can be described, in the 20 keV - 1.5 MeV range, by a power law with
exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.23(-0.32,+0.40) and Ep = 678(-141,+254) keV.


All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.


GRB_name: GRB240122A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35595
SUBJECT: GRB 240122A: Tiled Swift observations
DATE:    24/01/22 16:50:08 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>


P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 240122A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00119

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240122A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35596
SUBJECT: GRB 240122A: GOTO optical counterpart candidate
DATE:    24/01/22 18:50:31 GMT
FROM:    Amit Kumar at University of Warwick, UK <amitkundu515@gmail.com>

A. Kumar; B. P. Gompertz; K. Ackley; G. Ramsay; R. Starling; M. J. Dyer; J. Lyman; K. Ulaczyk; F. Jimenez-Ibarra; D. O'Neill; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:

The Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) serendipitously covered the localisation region of MAXI/GSC detected GRB 240122A (Negoro et al. GCN 35593) at 11:11:43 UT on 2024-01-22 (43.6 minutes after trigger). Each observation consisted of 4x45s exposures in the GOTO L-band (400-700 nm).

Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.

We identify 1 new optical transient (GOTO24eu/AT2024apy) within the MAXI/GSC uncertainty region. We find no evidence of this source prior to the GRB trigger time in the previous GOTO epoch at 2024-01-21 12:06:42 (22.4 hours prior), to a 5 sigma limiting magnitude of L > 19.8. The source was also not present in the ZTF observations provided by the Lasair broker (Smith et al. 2019), or the ATLAS forced photometry server (Shingles et al. 2021).

Name | RA(J2000) | Dec(J2000) | Filter | Mag(AB)
GOTO24eu/AT2024apy | 06:12:12.91| -19:08:38.81 | L | 17.06 +/- 0.04

Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.

Observations are ongoing.
GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).


GRB_name: GRB240122A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35597
SUBJECT: GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
DATE:    24/01/23 00:32:46 GMT
FROM:    Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>

B. P. Gompertz (U. Birmingham) reports for a larger collaboration:


We observed the position of the GOTO candidate optical counterpart (Kumar et al, GCN 35596) to the MAXI-detected GRB 240122A (Negoro et al, GCN 35593) with the IO:O optical camera on the 2m robotic Liverpool Telescope. Observations consisted of 3x60s exposures in each of the SDSS r, i, and z filters under seeing of 2.1â€, beginning at 23:36:51 UT on 2024-01-22, 13.1 hours after the GRB trigger. We do not detect the source to a 3-sigma limiting magnitude of r(AB) > 19.36. This non-detection indicates fading of more than two magnitudes in the ~12.4 hours since the GOTO detection.
Magnitudes were calibrated to PS1 stars and are not corrected for Galactic extinction.


GRB_name: GRB240122A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35598
SUBJECT: GRB 240122A: Redshift from OSIRIS+/GTC
DATE:    24/01/23 01:06:27 GMT
FROM:    Christina ThÃ¶ne at ASU-CAS <christina.thoene@gmail.com>

C. C. Thoene (ASU-CAS), A. de Ugarte Postigo (CNRS/OCA and LAM), J. F. Agui Fernandez (CAHA), L. Izzo (INAF/Capodimonte), J. P. U. Fynbo (DAWN/NBI), N. R. Tanvir (U. Leicester), M. Blazek (CAHA), S. Geier, A. Garcia-Rodriguez, Miguel Rivero Mendez (both GTC) report: 

We obtained spectroscopy of the optical afterglow (Kumar et al. GCN 35596) of the MAXI/GSC GRB 240122A (Negoro et al. GCN 35593) with OSIRIS+ at the 10.4m GTC at a mean epoch of 0.5357 days after the GRB. The observation consisted of 3x900s exposures using grism R1000B, which covers the range between 3700 and 7780 AA at a resolving power of about 600. The observation was strongly impacted by the nearby Moon and poor seeing.

A preliminary reduction of the spectrum shows a continuum with multiple absorption features. We determine the redshift of the GRB indentifying Lyman alpha and Lyman beta as well as absorption features of SiII, SiIV, CI, CII, CIV and FeII at a common redshift of z=3.162. We note that the Lyman series is rather weak compared to typical GRB  sight lines.


GRB_name: GRB240122A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35599
SUBJECT: GRB 240122A: VLT/X-shooter redshift confirmation
DATE:    24/01/23 09:17:34 GMT
FROM:    Andrea Saccardi at Observatoire de Paris <andrea.saccardi@obspm.fr>

A. Saccardi (GEPI, Observatoire de Paris), B. Sbarufatti (INAF-OAB), D. B. Malesani (DAWN/NBI & Radboud Univ.), L. Izzo (INAF-OACn & DARK/NBI), A. de Ugarte Postigo (CNRS/OCA & LAM), S. Campana (INAF-OAB), A. J. Levan (Radboud Univ. & Warwick Univ.), D. Hartmann (Clemson University) report on behalf of the Stargate collaboration:

Following the discovery of GOTO24eu/AT2024apy (Kumar et al. 2024, GCN 35596) within the error box of MAXI/GSC GRB 240122A (Negoro et al. 2024, GCN 35593), we acquired a spectrum of the optical counterpart candidate using the ESO/VLT/UT3 (Melipal) equipped with the X-shooter spectrograph. It covers the wavelength range 3000-21000 AA, and consists of 4 exposures of 1200 s each. Observations started at 02:25:37 UT on Jan 23 2024 (~16 hr after the trigger).

We detect a continuum over the entire wavelength range. From the detection of a rather weak Lya absorption at ~5060 AA and multiple absorption features, which we interpret as being due to SiII, CII, MgII, SiIV and CIV, we infer a common redshift of z = 3.162 (consistent with Thoene et al. 2024, GCN 35598). We conclude this is the redshift of the burst. We also note the presence of additional absorption features likely due to multiple intervening systems, one of them very strong at z = 2.757 with a broad Lya at ~4570 AA. 

We acknowledge the excellent support from the ESO observing staff in Paranal, in particular Felipe Gaete and Jonathan Smoker.


GRB_name: GRB240123A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35602
SUBJECT: GRB 240123A: Swift detection of a burst with a possible optical counterpart
DATE:    24/01/23 11:34:56 GMT
FROM:    Antonino D'Ai' at IASF-PA <antonino.dai@inaf.it>


A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), J.D. Gropp (PSU), J. A. Kennea (PSU),
A. Y. Lien (U Tampa), A. Melandri (INAF-OAR),
K. L. Page (U Leicester), T. M. Parsotan (GSFC/UMBC/CRESSTII) and
B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 11:05:46 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240123A (trigger=1210276).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 199.319, +60.632 which is 
   RA(J2000) = 13h 17m 16s
   Dec(J2000) = +60d 37' 53"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about 25 sec.  The peak count rate
was ~500 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 11:08:08.6 UT, 141.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 199.34797,
60.61894 which is equivalent to:
   RA(J2000)  = 13h 17m 23.51s
   Dec(J2000) = +60d 37' 08.2"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 69 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.45 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.7
(+2.69/-2.33) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 7.30e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 151 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 13:17:23.25 = 199.3468
  DEC(J2000) = +60:37:04.4  = 60.6179
with a 90%-confidence error radius of about 0.2 arc sec. This position is 4.3
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.9 with a 1-sigma error of about 0.2. No correction has been made for the
expected extinction. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240112A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35603
SUBJECT: Konus-Wind detection of GRB 240112A
DATE:    24/01/23 11:56:59 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long-duration GRB 240112A
(GECAM-B detection: Wang and Xiong, GCN 35520;
IPN triangulation: Kozyrev et al., GCN 35554)
triggered Konus-Wind at T0=20481.732 s UT (05:41:21.732).

The burst light curve shows the main multi-peaked episode,
which starts at ~T0-0.2 s and has a total duration of ~2.8 s.
A fainter broad pulse is observed in the KW data from ~T0+113 s
to ~T0+120 s after the main pulse, whose association with
GRB 240112A is supported by the consistent KW ecliptic
latitude response. 

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240112_T20481/

As observed by Konus-Wind, the burst (main episode)
had a fluence of 7.58(-1.05,+1.13)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+1.376 s,
of 1.03(-0.19,+0.20)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the main episode
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.04(-0.21,+0.23),
the high energy photon index beta = -2.67(-0.73,+0.26),
the peak energy Ep = 120(-15,+20) keV
(chi2 = 118/75 dof).

The spectrum of the fainter broad pulse
(measured from T0+106.752 to T0+123.136 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.67(-0.32,+0.53)
and Ep = 206(-195,+1360) keV (chi2 = 71/86 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.0
(chi2 = 71/85 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240123A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35605
SUBJECT: GRB 240123A: Mondy optical afterglow observations
DATE:    24/01/23 15:52:15 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI),  A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB IKI FuN:

We observed the field of GRB 231117A (D'Ai et al., GCN 35602) with AZT-33IK telescope of Mondy observatory  in  R-filter starting on 2024-01-23 (UT) 14:00:48.  We clearly detect a new fading object at coordinates (J2000) 13 17 23.87 +60 37 05.3 with uncertainties  of  0.2 arcsec which is slightly differ from coordinates reported by UVOT (D'Ai et al., GCN 35602). The object is absent in SDSS catalogue. Preliminary photometry is following

Date       UT start  t-T0     Exp.   Filter   OT     Err.
                   (mid, days)  (s)
2024-01-23 14:00:48  0.126415  7x120 R        19.07  0.10 20.9
2024-01-23 14:20:48  0.144479 13x120 R        19.25  0.10 21.3  
2024-01-23 14:46:49  0.163934 15x120 R        19.37  0.11 21.3  

The photometry is based on nearby USNO-B1.0 R2 stars. 


GRB_name: GRB240122B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35606
SUBJECT: GRB 240122B: Glowbug gamma-ray detection
DATE:    24/01/23 17:26:28 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J.E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240122B, which was also detected by CALET/CGBM (Trigger 1389985993).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-22 19:16:24.160 with a duration of 21.5 s and a total significance of about 28.9 sigma.  The light curve comprises a single peak.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=2.2 and a cutoff energy ("Epeak") of 211 keV.  The modeled 10-10000 keV fluence is 2.0e-06 erg/cm^2.
 
The best-fit localization is RA, Decl. (J2000, deg) = 22.8, 59.3 with a radius of 12.4 deg (95% confidence), with a highly uncertain systematic uncertainty.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240118A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35607
SUBJECT: GRB 240118A: Swift/UVOT Upper Limits
DATE:    24/01/23 17:35:39 GMT
FROM:    Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>

M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240118A
96191 s after the LAT trigger (Bissaldi et al., GCN Circ. 35560). No optical afterglow consistent with the
LAT position or the XRT position (Beardmore et al., GCN Circ. 35587)  is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

u                96191       103639         3161         >20.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.056 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240123B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35608
SUBJECT: GRB 240123B: Fermi GBM Final Real-time Localization
DATE:    24/01/23 17:58:30 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 17:48:03 UT on 23 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240123B (trigger 727724888.218344 / 240123742).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 312.7, Dec = 17.3 (J2000 degrees, equivalent to J2000 20h 50m, 17d 18'), with a statistical uncertainty of 6.9 degrees.

The angle from the Fermi LAT boresight is 51.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240123742/quicklook/glg_skymap_all_bn240123742.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240123742/quicklook/glg_healpix_all_bn240123742.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240123742/quicklook/glg_lc_medres34_bn240123742.gif


GRB_name: GRB240123A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35609
SUBJECT: GRB 240123A: Mondy continued optical observations + correction of the GRB name in GCN 35605
DATE:    24/01/23 18:06:11 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI),  A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB IKI FuN:

We continued to observe the afterglow of GRB 240123A (D'Ai et al., GCN 35602) with AZT-33IK telescope of Mondy observatory  in  R-filter originally started on 2024-01-23 (UT) 14:00:48 (Pankov et al., GCN 35605). We confirm the afterglow decay, which  detected previously (D'Ai et al., GCN 35602; Pankov et al., GCN 35605).  

Preliminary photometry of the afterglow is following

Date       UT start  t-T0     Exp.   Filter   OT     Err. UL(3sigma)
                   (mid, days)  (s)

2024-01-23 16:03:39  0.227009 29x120 R        19.87  0.10 21.9

The photometry is based on nearby USNO-B1.0 R2 stars. 

We are also reporting the incorrect name of the GRB in GCN Circular No. 35605. The correct name of the GRB in GCN Circular #3560 should be GRB 240123A.


GRB_name: GRB240123A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35610
SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 240123A
DATE:    24/01/23 19:36:21 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

L. Scotton (UAH) reports on behalf of the Fermi-GBM Team:

Swift-BAT detected GRB 240123A at 11:05:46 UT (D'Ai et al. 2024, GCN 35602). There was no
Fermi-GBM onboard trigger around the event.

An automated, blind search for short gamma-ray bursts below the onboard
triggering threshold in Fermi-GBM identified no counterparts.

The GBM targeted search [1], the most sensitive, coherent search for
GRB-like signals identified a transient most significantly on the 8.192 s
timescale, with a false alarm rate of 3.9e-05 Hz and a location consistent with
the Swift-BAT event, using the standard search protocol with a S/N of 13. 
The GBM targeted search event was found with the highest
significance with a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB.

[1] Goldstein et al. 2019 arXiv:1903.12597


GRB_name: GRB240122A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35611
SUBJECT: GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
DATE:    24/01/23 19:50:44 GMT
FROM:    Youdong HU at IAA-CSIC <huyoudong072@hotmail.com>

Y.-D. Hu, F. Aceituno, E. Fernandez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia, S.-Y. Wu, S. Guziy  (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC) and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:

Following the detection of GRB 240122A by MAXI/GSC (Negoro et al., GCNC 35593), we triggered the 0.6m BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) in Algarrobo Costa (Malaga, Spain), and pointing to the burst position on Jan. 22 at 19:45 UT (i.e. ~9.3 hrs after trigger). In the co-added image (14 x 60 s, clear filter, affected by the bright moonlight), the optical afterglow reported by GOTO (Kumar et al. GCNC 35596), GTC (Thoene et al. GCNC 35598) and VLT (Saccardi et al. GCNC 35599) is not detected down to 17.6 mag, which is consistent with the limit reported by LT (GCNC 35597).

Later on, we triggered the 1.5m telescope at Observatorio de Sierra Nevada (OSN) near Granada, Spain, starting on Jan. 22 at 23:46 UT (i.e. 13.3 hrs after trigger) in BVRI bands. The afterglow is clearly detected with I~20.1+-0.1 mag in the co-added image (7 x 90 s), and consistent with the enhanced XRT/Swift position (Ambrosi et al. GCNC 35600). Further imaging is ongoing.

We thank the staff at both IHSM/UMA-CSIC La Mayora and OSN for their excellent support.


GRB_name: GRB240123A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35612
SUBJECT: GRB 240123A: Swift-XRT refined Analysis
DATE:    24/01/23 22:11:25 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

M. Capalbi (INAF-IASFPA), M. Perri (SSDC & INAF-OAR), J. D. Gropp
(PSU), S. Dichiara (PSU), J.A. Kennea (PSU), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), V.
D'Elia (SSDC & INAF-OAR) and P.A. Evans report on behalf of the
Swift-XRT team:

We have analysed 6.5 ks of XRT data for GRB 240123A, from 131 s to 23.7
ks after the  BAT trigger. The data comprise 164 s in Windowed Timing
(WT) mode (the first 8 s were taken while Swift was slewing) with the
remainder in Photon Counting (PC) mode. The refined XRT position is RA,
Dec = 199.3473, +60.6184 which is equivalent to:

RA (J2000): 13 17 23.34
Dec(J2000): +60 37 06.1

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=7.2 (+0.8, -2.8). At T+145 s  the decay
flattens to an alpha of 0.3 (+1.0, -1.8). The light curve breaks again
at T+183 s to a decay with alpha=2.91 (+0.20, -0.19),  before a final
break at T+635 s s after which the decay index is 0.58 (+/-0.08).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.35 (+0.09, -0.07). The
best-fitting absorption column is  consistent with the Galactic value
of 1.4 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 2.01 (+0.17, -0.13) and a best-fitting absorption
column of 2.3 (+3.3, -0.9) x 10^20 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.2 x 10^-11 (3.4 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.3 (+3.3, -0.9) x 10^20 cm^-2
Galactic foreground: 1.4 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.01 (+0.17, -0.13)

If the light curve continues to decay with a power-law decay index of
0.58, the count rate at T+24 hours will be 0.028 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.0 x
10^-13 (9.6 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01210276.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240122A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35613
SUBJECT: GRB 240122A: Swift/UVOT Upper Limits
DATE:    24/01/23 22:57:57 GMT
FROM:    Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>

M. H. Siegel (PSU) and and V. Dâ€™Elia (SSDC & INAF-OAR) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240122A
from 29.5 ks to 35.6 ks after the MAXI trigger (Negoro et al., GCN Circ. 35593).
No optical afterglow consistent with either the optical (Kumar et al., GCN
Circ. 35596) or X-ray (Ambrosi et al., GCN Circ. 3600) position is detected in the initial
UVOT exposures. The lack of detection in the u-band would be consistent with the
redshift of 3.162 given by Saccardi et al. (GCN Circ. 35599).

Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures of
the candidate afterglow field are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

u                35166       35655          481         >20.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.064 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240123B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35614
SUBJECT: Fermi GRB 240123B: Global MASTER-Net observations report
DATE:    24/01/23 23:15:32 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Tunka robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 240123B ( Fermi GBM team, GCN 35608) errorbox  17492 sec after notice time and 17523 sec after trigger time at 2024-01-23 22:40:06 UT, with upper limit up to  17.1 mag. The observations began at zenith distance = 79 deg. The sun  altitude  is -21.0 deg. 

The galactic latitude b = -17 deg., longitude l = 64 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2363736

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   17534 | 2024-01-23 22:40:06 |        MASTER-Tunka | (20h 45m 43.98s , +25d 49m 07.9s) |   C |    20 | 16.9 |        
   17626 | 2024-01-23 22:41:41 |        MASTER-Tunka | (20h 25m 46.01s , +22d 02m 50.8s) |   C |    15 | 16.9 |        
   17669 | 2024-01-23 22:42:23 |        MASTER-Tunka | (20h 26m 42.78s , +23d 55m 03.1s) |   C |    15 | 17.1 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240123A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35616
SUBJECT: GRB 240123A: Enhanced Swift-XRT position
DATE:    24/01/24 03:40:02 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 596 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 240123A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 199.34861, +60.61849 which is equivalent
to:

RA (J2000): 13h 17m 23.67s
Dec (J2000): +60d 37' 06.6"

with an uncertainty of 2.1 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB240123A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35618
SUBJECT: GRB 240123A : MITSuME Akeno optical afterglow candidate detection
DATE:    24/01/24 08:57:45 GMT
FROM:    Mahito Sasada at Tokyo Institute of Technology <sasada@hp.phys.titech.ac.jp>

M. Sasada, I. Takahashi, N. Higuchi, M. Niwano, S. Sato, S. Hayatsu, H. Takei, H. Seki, Y. Yatsu and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 240123A (D'Ai et al. GCN 35602) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno. 

The observation with a series of 60 sec exposures started at 2024-01-23 15:09:01 UT (4.05 hours after the Swift/BAT trigger). We stacked the images in good conditions. An optical candidate of the afterglow can be found at the location of (RA, Dec) = (199.3495, 60.6181) near the Swift/XRT error position (Capalbi et al. GCN 35612). Here we report magnitudes by the aperture photometry at the position.

T0+[hours] | MID-UT | T-EXP[sec] | magnitudes of aperture photometry
----------------------------------------------------------------------------------------------------------------
5.0 | 2024-01-23 16:05:41 | 5880 | gâ€™=19.83+/-0.17, Rc=19.35+/-0.11, Ic=19.24+/-0.13
----------------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the trigger
T-EXP: Total Exposure time

The position of the optical candidate is consistent with Pankov et al., GCN 35605.

We used the PS1 catalog for flux calibration. The catalog magnitudes in PS1 g, r and i bands were converted to our g'-, Rc- and Ic-band magnitudes following Tonry et al. (2012), Table 6. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB240123A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35620
SUBJECT: GRB 240123A: Mondy continued optical observations and the PL decay index
DATE:    24/01/24 15:44:05 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI),  A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) report on behalf of GRB IKI FuN:

We continued to observe the afterglow of GRB 240123A (D'Ai et al., GCN 35602; Pankov et al., GCN 35605, GCN 35609; Sasada et al., GCN 35618; Moskvitin at al., GCN 35619) with AZT-33IK telescope of Mondy observatory  in  R-filter.   

Using previously reported photometry  (Pankov et al., GCN 35605, GCN 35609; Moskvitin at al., GCN 35619) and photometry  obtained  on t-T0 0.400722 we approximate the light curve with a PL model with the index of PL alpha = -1.1, see Figure at 
http://grb.rssi.ru/GRB240123A/GRB240123A_LC_approximation.jpg 


GRB_name: GRB240123A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35622
SUBJECT: GRB 240123A: Swift-BAT refined analysis
DATE:    24/01/24 18:12:15 GMT
FROM:    Amy <yarleen@gmail.com>

T. Parsotan (GSFC), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), M. J. Moss (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+820 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 240123A (trigger #1210276)
(D'Ai, et al., GCN Circ. 35602).  The BAT ground-calculated position is
RA, Dec = 199.287, 60.607 deg which is
   RA(J2000)  =  13h 17m 08.9s
   Dec(J2000) = +60d 36' 25.6"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 31%.

The mask-weighted light curve shows some weak emission with complex
structures
that starts at ~T0 and ends at ~T+140 s. The main peak occurs at ~T+5 s.
T90 (15-350 keV) is 115.30 +- 54.93 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.69 to T+140.46 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.69 +- 0.23.  The fluence in the 15-150 keV band is 1.6 +- 0.2 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+5.49 sec in the 15-150 keV band
is 1.1 +- 0.3 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1210276/BA/


GRB_name: GRB240122B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35623
SUBJECT: GRB 240122B: CALET Gamma-Ray Burst Monitor detection
DATE:    24/01/24 20:04:13 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, 
S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U),
S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, 
K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), 
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 240122B (Glowbug gamma-ray detection: 
Cheung et al., GCN Circ. 35606) triggered the CALET 
Gamma-ray Burst Monitor (CGBM) at 19:16:26.96 UTC 
on 22 January 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1389985993/).
The burst signal was seen by HXM2 and SGM.

The burst light curve shows a double-peaked structure that starts
at T-57.2 sec, peaks at T+9.0 sec, and ends at T+17.1 sec.
The T90 and T50 durations measured by the SGM data are 
69.2 +/- 1.9 sec and 32.2 +/- 19.7 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1389985993/index.html

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB240123A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35624
SUBJECT: GRB 240123A: further SAO RAS optical observations
DATE:    24/01/25 05:12:41 GMT
FROM:    Moskvitin Alexander at SAO RAS <mosk@sao.ru>

A. S. Moskvitin, O. A. Maslennikova, O. I. Spiridonova (SAO RAS)
report on behalf of the GRB follow-up team.

We observed the field of GRB 240123A (D'Ai et al., GCN #35602;
Scotton, GCN #35610) with the 1-m telescope of SAO RAS equipped
with the CCD photometer. We obtained 16 x 300 sec. images in Rc
band on Jan 25, 01:55:52 -- 03:30:49 UT (t_mid - T0 = 1.6511 days).

The OT (D'Ai et al., GCN #35602; Pankov et al., GCNs #35605, #35609
#35620; Sasada et al., GCN #35618) is detected in our stacked frame
with the brightness of R = 22.0 +/- 0.2.

The photometry is based on R2 magnitudes of nearby USNO-B1.0 stars.


GRB_name: GRB240123C
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35627
SUBJECT: IPN triangulation of GRB 240123C (short)
DATE:    24/01/25 11:35:17 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,

A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

The short-duration GRB 240123C
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
Swift (BAT), and Mars-Odyssey (HEND)
at about 83553 s UT (23:12:33). 
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  244.077 (16h 16m 19s) -58.857 (-58d 51' 25")
 Corners:
  240.883 (16h 03m 32s) -55.715 (-55d 42' 55")
  241.066 (16h 04m 16s) -56.037 (-56d 02' 14")
  248.066 (16h 32m 16s) -61.657 (-61d 39' 24")
  247.747 (16h 30m 59s) -61.386 (-61d 23' 11")
 ---------------------------------------------
The error box area is 1219 sq. arcmin, and its maximum
dimension is 7.0 deg (the minimum one is 3 arcmin).
The Sun distance was 58 deg.

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240123_T83553/IPN

The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.


GRB_name: GRB240123A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35628
SUBJECT: GRB 240123A: GRBAlpha detection
DATE:    24/01/25 14:21:21 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240123A (Swift/BAT detection: GCN 35602; Fermi/GBM detection: GCN 35610; INTEGRAL/SPI-ACS peak detection at 2024-01-23 ~11:05:47) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The subthreshold detection was confirmed at the peak time 2024-01-23 11:05:49 UTC. The T90 duration measured by GRBAlpha is 8 s and the overall significance during T90 reaches 3.5 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240123A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240123B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35629
SUBJECT: GRB 240123B: Swift/BAT-GUANO detection of a long burst
DATE:    24/01/25 16:01:37 GMT
FROM:    Samuele Ronchini at PSU <sjs8171@psu.edu>

Samuele Ronchini (PSU), James DeLaunay (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:

Swift/BAT did not localize GRB 240123B onboard (T0: 2024-01-23T17:48:03.22 UTC, Fermi GCN 35608). 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 15.5 in a 8.192 s analysis time bin, starting at T0 - 2.05 s. 

NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 2.75.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240125A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35630
SUBJECT: GRB 240125A (short): Glowbug gamma-ray detection
DATE:    24/01/25 18:08:11 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

GRB 240125A (short): Glowbug gamma-ray detection
 
C.C. Cheung, M. Kerr, J.E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of the short GRB 240125A, which was also detected by CALET/CGBM (Trigger 1390210300).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-25 09:34:59.200 with a duration of 1.28 s and a total significance of about 51.2 sigma.  The light curve comprises a triple-peaked structure.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=0.8 and a cutoff energy ("Epeak") of 705 keV.  The modeled 10-10000 keV fluence is 3.2e-06 erg/cm^2.
 
The best-fit localization is RA, Decl. (J2000, deg) = 153.4, 48.7 with a radius of 9.3 deg (95% confidence), with a highly uncertain systematic uncertainty.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240123A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35631
SUBJECT: GRB 240123A: Glowbug gamma-ray detection
DATE:    24/01/25 18:11:33 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J.E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240123A, which was also detected by Swift/BAT (GCN 35602, 35622), Fermi/GBM (GCN 35610), and GRBAlpha (GCN 35628). 
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-23 11:05:48.840 with a duration of 6.1 s and a total significance of about 12.2 sigma.  The light curve comprises a single peak.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=-0.4 and a cutoff energy ("Epeak") of 719 keV.  The modeled 10-10000 keV fluence is 1.3e-06 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240123B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35632
SUBJECT: GRB 240123B: Fermi GBM Observation
DATE:    24/01/25 19:45:45 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

L. Scotton (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 17:48:03.22 UT on 23 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240123B (trigger 727724888/240123742).
which was also detected by Swift/BAT-GUANO (Ronchini et al. 2024, GCN 35629).
The Fermi GBM Final Real-time Localization was reported in GCN 35608.

The angle from the Fermi LAT boresight is 51 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 12 s (50-300 keV). The time-averaged spectrum
from T0-0.5 to T0+11.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.6 +/- 0.2 and the cutoff energy,
parameterized as Epeak, is 250 +/- 30 keV.

The event fluence (10-1000 keV) in this time interval is
(2.6 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.9 s in the 10-1000 keV band is 2.4 +/- 0.2 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 130 +/- 30 keV, alpha = 0.1 +/- 0.4 and beta = -1.9 +/- 0.1.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240122A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35633
SUBJECT: GRB240122A: PRIME near infrared detection
DATE:    24/01/25 20:05:40 GMT
FROM:    Joe Durbak at UMD <gcn.joedurbak@gmail.com>


O. Guiffreda (UMD), J. Durbak (UMD), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), K. De (MIT), S. B. Cenko (NASA/GSFC)


Following the MAXI/GSC detection (Negoro et al. GCN 35593), GOTO optical candidate GOTO24eu/AT2024apy (Kumar et al. GCN 35596), and the Swift afterglow detection (Ambrosi et al. GCN 35600), we observed the transient field using J and H filters with PRIME ~1.5 days after MAXI/GSC detection.


At the position of the optical counterpart detected by GOTO, we detect an uncatalogued source in both J and H bands. Using nearby 2MASS stars for preliminary calibration we derive the following magnitudes, not corrected for Galactic extinction:  


Filter | Mag(AB)        | SNR | Seeing | Total exposure time (s) 

-------|----------------|-----|--------|-------------------------

J      | 21.02 +/- 0.20 | 6.3 | 1.373â€ | 1802

H      | 20.90 +/- 0.21 | 6.1 | 1.480â€ | 1544



PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa.


Further observations are planned.


We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.


GRB_name: GRB240125B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35634
SUBJECT: GRB 240125B: Fermi GBM Final Localization
DATE:    24/01/26 02:54:31 GMT
FROM:    Cori Fletcher at USRA <cfletcher@usra.edu>

The Fermi GBM team reports the detection of a likely SHORT GRB

"At 20:48:42.61 UT on 25 January 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240125B (trigger 727908527/240125867).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 81.10, Dec = 21.10 (J2000 degrees, equivalent to J2000 5h 24m, +21d 6'),
with a statistical uncertainty of 16.96 degrees.

The angle from the Fermi LAT boresight is 78 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240125867/quicklook/glg_skymap_all_bn240125867.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240125867/quicklook/glg_healpix_all_bn240125867.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240125867/quicklook/glg_lc_medres34_bn240125867.gif"


GRB_name: GRB240123C
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35635
SUBJECT: GRB 240123C: AstroSat CZTI detection
DATE:    24/01/26 08:25:49 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a short-duration GRB 240123C which was also detected by Konus-Wind, INTEGRAL (SPI-ACS), Swift (BAT), and Mars-Odyssey (HEND) (A.S. Kozyre, GCN Circ. 35627).

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-23 23:12:36.55 UTC. The measured peak count rate associated with the burst is 1936 (+240, -237) counts/s above the background in the combined data of all quadrants, with a total of 798 (+116, -73) counts. The local mean background count rate was 312 (+8, -15) counts/s. Using cumulative rates, we measure a T90 of 1.4 (+0.61, -0.38) s.

The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-23 23:12:36.81 UTC. The measured peak count rate associated with the burst is 560 (+70, -77) counts/s above the background in the combined data of all quadrants, with a total of 1166 (+263, -284) counts. The local mean background count rate was 1288 (+11, -11) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 from it.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240124B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35636
SUBJECT: GRB 240124B: AstroSat CZTI detection
DATE:    24/01/26 08:28:51 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of GRB 240124B. We also inspected INTEGRAL/SPI-ACS data, and see a detection there.

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-24 21:14:33.25 UTC. The measured peak count rate associated with the burst is 386 (+141, -69) counts/s above the background in the combined data of three quadrants (out of four), with a total of 322 (+81, -76) counts. The local mean background count rate was 257 (+5, -10) counts/s. Using cumulative rates, we measure a T90 of 2.35 (+0.34, -0.9) s.

The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-23 21:14:31.78 UTC. The measured peak count rate associated with the burst is 710 (+72, -80) counts/s above the background in the combined data of all quadrants, with a total of 1164 (+159, -179) counts. The local mean background count rate was 1303 (+6, -8) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 from it.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240125A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35637
SUBJECT: GRB 240125A: AstroSat CZTI detection of a short burst
DATE:    24/01/26 08:30:34 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

J.Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a short-duration GRB 240125A which was also detected by Glowbug (C.C. Cheung, GCN Circ. 35630).

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-01-25 09:35:00.35 UTC. The measured peak count rate associated with the burst is 287 (+139, -40) counts/s above the background in the combined data of three quadrants (out of four), with a total of 208 (+50, -50) counts. The local mean background count rate was 263 (+7, -10) counts/s. Using cumulative rates, we measure a T90 of 1.4 (+0.11, -0.47) s.

The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-23 09:34:58.75UTC. The measured peak count rate associated with the burst is 532 (+74, -81) counts/s above the background in the combined data of all quadrants, with a total of 1132 (+156, -172) counts. The local mean background count rate was 1587 (+5, -6) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 from it.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240125A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35639
SUBJECT: GRB 240125A: CALET Gamma-Ray Burst Monitor detection
DATE:    24/01/27 00:35:22 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

P. S. Marrocchesi (U of Siena), A. Yoshida, T. Sakamoto,
S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U),
S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, 
K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), 
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), 
S. Ricciarini (U of Florence),
and the CALET collaboration:

The short GRB 240125A (Glowbug gamma-ray detection: 
Cheung et al., GCN Circ. 35630; AstroSat CZTI detection: 
Joshi et al.,  GCN Circ. 35637) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 09:34:58.79 UTC on 25 January 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1390210300/).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a triple-peaked structure that 
starts at T+0.50 sec, peaks at T+1.02 sec, and ends at T+1.65 sec.
The T90 and T50 durations measured by the SGM data are 
1.10 +/- 0.05 sec and 0.65 +/- 0.11 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1390210300/index.html

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB240127A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35641
SUBJECT: GRB 240127A: Fermi GBM Final Real-time Localization
DATE:    24/01/27 05:01:10 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 04:50:40 UT on 27 Jan 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240127A (trigger 728023845.52457 / 240127202).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 299.9, Dec = -62.8 (J2000 degrees, equivalent to J2000 19h 59m, -62d 47'), with a statistical uncertainty of 29.9 degrees.

The angle from the Fermi LAT boresight is 129.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240127202/quicklook/glg_skymap_all_bn240127202.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240127202/quicklook/glg_healpix_all_bn240127202.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240127202/quicklook/glg_lc_medres34_bn240127202.gif


GRB_name: GRB240122A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35642
SUBJECT: GRB 240122A: ATCA detection of radio counterpart
DATE:    24/01/27 06:27:28 GMT
FROM:    Gemma Anderson at Curtin U <gemma.anderson@curtin.edu.au>

G. E. Anderson (Curtin), A. Gulati (USyd), L. Rhodes (Oxford), J. K. Leung (UofT/HUJI), A. J. van der Horst (GWU), S. Chastain (UNM) on behalf of the PanRadio GRB collaboration

The Australia Telescope Compact Array (ATCA) observed the MAXI-detected long GRB 240122A (Negoro et al., GCN 35593) at the GOTO (Kumar et al., GCN 35596) and Swift-XRT localisation (Ambrosi et al., GCN 35600) as part of the Large ATCA "PanRadio GRB" follow-up program C3542 (PI. Anderson).

The observation took place on 2024-01-24 at 12:00 UT for 2.5 hours at 5.5 and 9 GHz. We detected a candidate radio afterglow at 9 GHz consistent with the GOTO and XRT position with a preliminary flux density of ~160 microJy with a RMS sensitivity of 20 microJy, and obtained a 3 sigma upper limit of 135 microJy at 5.5 GHz.

Further observations are planned.

We thank the CSIRO Space and Astronomy staff for supporting these observations.
We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO.


GRB_name: GRB240123C
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35643
SUBJECT: GRB 240123C: GRBAlpha detection
DATE:    24/01/27 16:19:42 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The short-duration GRB 240123C (AstroSat detection: GCN 35635; INTEGRAL/SPI-ACS peak detection at 2024-01-23 ~23:12:37) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-01-23 23:12:37 UTC. The T90 duration measured by GRBAlpha is 2 s and the overall significance during T90 reaches 12 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240123C_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240127A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35644
SUBJECT: Fermi GRB 240127A: Global MASTER-Net observations report
DATE:    24/01/27 19:31:24 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240127A ( Fermi GBM team, GCN 35641) errorbox  50416 sec after notice time and 50449 sec after trigger time at 2024-01-27 18:51:29 UT, with upper limit up to  18.4 mag. Observations started at twilight.  The observations began at zenith distance = 79 deg. The sun  altitude  is -13.5 deg. 

The galactic latitude b = -32 deg., longitude l = 334 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2365466

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   50479 | 2024-01-27 18:51:29 |         MASTER-SAAO | (21h 13m 34.50s , -48d 04m 39.1s) |   C |    60 | 17.2 |        
   50479 | 2024-01-27 18:51:29 |         MASTER-SAAO | (21h 16m 12.91s , -48d 17m 24.0s) |   C |    60 | 17.8 |        
   50559 | 2024-01-27 18:52:49 |         MASTER-SAAO | (21h 16m 07.54s , -49d 59m 45.4s) |   C |    60 | 17.3 |        
   50559 | 2024-01-27 18:52:49 |         MASTER-SAAO | (21h 18m 52.23s , -50d 12m 29.7s) |   C |    60 | 17.8 |        
   50719 | 2024-01-27 18:55:29 |         MASTER-SAAO | (21h 07m 19.93s , -55d 42m 11.5s) |   C |    60 | 17.8 |        
   50719 | 2024-01-27 18:55:29 |         MASTER-SAAO | (21h 10m 27.84s , -55d 54m 56.1s) |   C |    60 | 18.3 |        
   50878 | 2024-01-27 18:58:08 |         MASTER-SAAO | (21h 20m 12.47s , -51d 53m 49.9s) |   C |    60 | 17.8 |        
   50878 | 2024-01-27 18:58:08 |         MASTER-SAAO | (21h 23m 04.13s , -52d 06m 33.9s) |   C |    60 | 18.4 |        
   50957 | 2024-01-27 18:59:27 |         MASTER-SAAO | (19h 58m 01.24s , -59d 27m 21.3s) |   C |    60 | 17.2 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240125A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35645
SUBJECT: GRB 240125A: GRBAlpha detection
DATE:    24/01/28 17:29:33 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The short-duration GRB 240125A (Glowbug detection: GCN 35630; AstroSat detection: GCN 35637; CALET/CGBM detection: GCN 35639; Konus/Wind trigger at 2024-01-25 09:35:03.601 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The subthreshold detection was confirmed at the peak time 2024-01-25 09:35:00 UTC. The T90 duration measured by GRBAlpha is 1 s and the overall significance during T90 reaches 4.4 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240125A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240128A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35646
SUBJECT: GRB 240128A: MAXI/GSC detection
DATE:    24/01/28 22:09:40 GMT
FROM:    Kazutaka Yamaoka at Nagoya Univ. <yamaoka@isee.nagoya-u.ac.jp>


K. Yamaoka (Nagoya U.), H. Negoro (Nihon U.), M. Serino (AGU),
W. Iwakiri (Chiba U.), M. Nakajima, K. Kobayashi, M. Tanaka, 
Y. Soejima, Y. Kudo (Nihon U.), T. Mihara, T. Kawamuro, S. Yamada, 
T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita,
H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), Y. Tsuboi, S. Urabe, 
S. Nawa, N. Nemoto, E.Goto (Chuo U.), M. Shidatsu, Y. Niida (Ehime U.),
I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA),
Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.),
M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.),
Y. Kawakubo (LSU), and M. Sugizaki (NAOC)


The MAXI/GSC nova alert system triggered on an uncatalogued X-ray
transient source at 15:14:03 UT on January 28, 2024.
Because our localization program did not run, we can not provide a
precise error region.
The source position determined with the nova alert system (Negoro et
al. 2016) is

(R.A., Dec) = (139.846 deg, -5.053 deg) = (09 19 23.04, -05 03 10.8) (J2000)

with an uncertainty of more than 30 arc-min. The burst duration is
about 30 sec, and the averaged X-ray flux in the 2-10 keV range was about 600 mCrab.
This event was also detected by INTEGRAL SPI-ACS. 
There was no significant excess flux in the previous transit at 13:37 UT
with an upper limit of 20 mCrab.


GRB_name: GRB240128A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35647
SUBJECT: GRB 240128A: CALET Gamma-Ray Burst Monitor detection
DATE:    24/01/28 23:37:46 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

A. Yoshida, T. Sakamoto, S. Sugita (AGU), Y. Kawakubo (LSU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 240128A (MAXI/GSC detection, Yamaoka et al., 
GCN Circ. 35646) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 15:13:34.34 UTC on 28 January 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1390489809/).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T+1.4 sec, peaks at T+10.8 sec, and ends at T+15.2 sec.
The T90 and T50 durations measured by the SGM data are 12.5 +/- 0.6 sec
and 7.2 +/- 0.6 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1390489809/index.html

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB240128A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35648
SUBJECT: GRB 240128A: Tiled Swift observations
DATE:    24/01/29 04:07:06 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>


P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 240128A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00120

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240128A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35649
SUBJECT: GRB 240128A: GRBAlpha detection
DATE:    24/01/29 15:48:15 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240128A (MAXI/GSC detection: GCN 35646; CALET/CGBM detection: GCN 35647; INTEGRAL/SPI-ACS trigger no. 10493) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-01-28 15:13:46 UTC. The T90 duration measured by GRBAlpha is 13 s and the overall significance during T90 reaches 8 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240128A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240128A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35650
SUBJECT: GRB 240128A: Swift-XRT observations
DATE:    24/01/29 15:53:21 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

M. Perri (SSDC & INAF-OAR), S. Dichiara (PSU), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB) and
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 240128A in a series of observations tiled on the sky. The
total exposure time is 1.4 ks, distributed over 6 tiles; the maximum
exposure at a single sky location was 460 s. The data were collected
between T0+46.4 ks and T0+52.4 ks, and are entirely in Photon Counting
(PC) mode. 

One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:

Source 1:
  RA (J2000):  140.1536  =  09:20:36.87
  Dec (J2000): -5.2004  =  -05:12:01.5
  Error: 8.8 arcsec (radius, 90% conf.)
  Count-rate: 0.0149 [+0.0080, -0.0059] ct s^-1   
  Distance: 1224 arcsec from MAXI position.
  Flux: (2.9 [+1.6, -1.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected.

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00120.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240128A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35651
SUBJECT: GRB 240128A: Glowbug gamma-ray detection
DATE:    24/01/29 16:07:31 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, M. Kerr, J.E. Grove, R. Woolf (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240128A, which was also detected by MAXI/GSC (GCN 35646), CALET/CGBM (GCN 35647), GRBAlpha (GCN 35649), and INTEGRAL/SPI-ACS (Trigger 10493).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-01-28 15:13:35.064 with a duration of 18.4 s and a total significance of about 44.8 sigma.  The light curve comprises a multi-peaked structure similar to that observed by CALET/CGBM (GCN 35647).
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.9 and a cutoff energy ("Epeak") of 176 keV.  The modeled 10-10000 keV fluence is 2.0e-06 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240129A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35653
SUBJECT: GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV 
DATE:    24/01/30 18:32:45 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: 

Swift/BAT did not localize GRB 240129A onboard (T0: 2024-01-29T15:09:22.53 UTC, Fermi trig 728233767) 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. 

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 15.8 in a 16.384 s analysis time bin, starting at T0 - 4.096 s. 

NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of 2.4.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. 

GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. 

A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240125B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35654
SUBJECT: IPN triangulation of GRB 240125B (short)
DATE:    24/01/30 19:43:07 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
on behalf of the IPN,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

and

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:

The short-duration GRB 240125B
(Fermi-GBM detection: The Fermi GBM team, GCN 35634)
was detected by Fermi (GBM trigger 727908527), and
INTEGRAL (SPI-ACS) at about 74923 s UT (20:48:43).

We have triangulated it to a GBM-SPI-ACS annulus centered at
RA(2000)=132.059 deg (08h 48m 14s) Dec(2000)=+85.090 deg (+85d 05' 24")
whose radius is 34.188 +/- 6.337 deg (3 sigma).

The annulus combined with the Fermi-GBM final position (GCN 35634;
glg_healpix_all_bn240125867_v00) and the Fermi Earth-occultation information gives 575 sq. deg (3 sigma) localization region.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240125_T74922/IPN/


GRB_name: GRB240123C
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35658
SUBJECT: Konus-Wind detection of GRB 240123C
DATE:    24/02/02 15:53:58 GMT
FROM:    Alexandra Lysenko at Ioffe Institute <alexandra.lysenko@mail.ioffe.ru>

A. Lysenko, D. Frederiks, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov,
and T. Cline on behalf of the Konus-Wind team, report:

The short-duration GRB 240123C
(IPN triangulation: Ridnaia et al., GCN circ. 35627;
AstroSat CZTI detection: Joshi et al., GCN circ. 35635;
GRBAlpha detection: Dafcikova et al., GCN circ. 35643)
triggered Konus-Wind at T0=83553.043 s UT (23:12:33.043).

The burst light curve shows a single-pulse structure
which starts at ~T0-0.1 s and has a total duration of ~1.0 s.
The emission is seen up to 1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240123_T83553/

As observed by Konus-Wind, the burst
had a fluence of 2.91(-0.22,+0.23)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.160s,
of 1.17(-0.32,+0.33)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

A time-averaged spectrum of the burst
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = 0.85(-0.40,+0.46)
and Ep = 210(-17,+19) keV (chi2 = 24/38 dof).
Fitting by a GRB (Band) model yields the close alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.8
(chi2 = 22/37 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240124B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35659
SUBJECT: Konus-Wind detection of GRB 240124B
DATE:    24/02/02 15:58:30 GMT
FROM:    Alexandra Lysenko at Ioffe Institute <alexandra.lysenko@mail.ioffe.ru>

A. Lysenko, D. Frederiks, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov,
and T. Cline on behalf of the Konus-Wind team, report:

The long-duration GRB 240124B
(AstroSat CZTI detection: Joshi et al., GCN 35636;
IPN triangulation: Ridnaia et al., GCN 35657)
triggered Konus-Wind at T0=76473.999 s UT (21:14:33.999).

The burst light curve shows a single-pulse structure
which starts at ~T0-1.1 s and has a total duration of ~4.0 s.
The emission is seen up to 3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240124_T76473/

As observed by Konus-Wind, the burst
had a fluence of 4.57(-0.85,+2.93)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.228s,
of 4.33(-1.37,+3.93)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

A time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.40(-0.35,+0.44)
and Ep = 270(-94,+1040) keV (chi2 = 113/97 dof).
Fitting by a GRB (Band) model yields close alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 112/96 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240204A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35664
SUBJECT: GRB 240204A: Fermi GBM Final Real-time Localization
DATE:    24/02/04 15:18:07 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 15:07:38 UT on 4 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240204A (trigger 728752063.677018 / 240204630).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 101.5, Dec = -3.4 (J2000 degrees, equivalent to J2000 06h 46m, -3d 23'), with a statistical uncertainty of 1.6 degrees.

The angle from the Fermi LAT boresight is 102.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240204630/quicklook/glg_skymap_all_bn240204630.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240204630/quicklook/glg_healpix_all_bn240204630.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240204630/quicklook/glg_lc_medres34_bn240204630.gif


GRB_name: GRB240204A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35666
SUBJECT: GRB 240204A: Swift detection of a burst
DATE:    24/02/04 15:33:54 GMT
FROM:    K.L. Page at U Leicester <klp5@leicester.ac.uk>


S. B. Cenko (GSFC), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of
the Neil Gehrels Swift Observatory Team:

Swift/BAT triggered on the Fermi/GBM reported long GRB 240204A (GCN #35664). 
Due to a telemetry outage, no realtime BAT data are available. 

The XRT began observing the field at 15:10:12.2 UT, 154 seconds
after the Fermi/GBM trigger. Using promptly downlinked data we find an
uncatalogued X-ray source located at RA, Dec 104.18190, 1.02767 which
is equivalent to:
   RA(J2000)  = 06h 56m 43.66s
   Dec(J2000) = +01d 01' 39.6"
with an uncertainty of 4.0 arcseconds (radius, 90% containment). This
position may be improved as more data are received; the latest position
is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 6.45
x 10^21 cm^-2 (Willingale et al. 2013). 

Due to a telemetry outage, there are no UVOT data available at this time. 

Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240204A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35668
SUBJECT: Fermi GRB 240204A: Global MASTER-Net observations report
DATE:    24/02/04 16:15:52 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Tunka robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 240204A ( Fermi GBM team, GCN 35664) errorbox  818 sec after notice time and 854 sec after trigger time at 2024-02-04 15:21:52 UT, with upper limit up to  20.8 mag. The observations began at zenith distance = 54 deg. The sun  altitude  is -48.0 deg. 

The galactic latitude b = -2 deg., longitude l = 216 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2371241

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     884 | 2024-02-04 15:21:52 |        MASTER-Tunka | (06h 45m 43.71s , -03d 13m 03.5s) |   C |    60 | 19.9 |        
     944 | 2024-02-04 15:21:52 |        MASTER-Tunka | (06h 45m 43.71s , -03d 13m 03.5s) |   C |   180 | 20.4 |  Coadd 
    1154 | 2024-02-04 15:21:52 |        MASTER-Tunka | (06h 45m 43.71s , -03d 13m 03.5s) |   C |   600 | 20.8 |  Coadd 
     947 | 2024-02-04 15:22:56 |        MASTER-Tunka | (06h 45m 43.78s , -03d 13m 01.1s) |   C |    60 | 19.9 |        
    1011 | 2024-02-04 15:23:59 |        MASTER-Tunka | (06h 45m 43.83s , -03d 12m 59.8s) |   C |    60 | 19.9 |        
    1074 | 2024-02-04 15:25:02 |        MASTER-Tunka | (06h 45m 43.88s , -03d 12m 57.8s) |   C |    60 | 19.9 |        
    1134 | 2024-02-04 15:25:02 |        MASTER-Tunka | (06h 45m 43.88s , -03d 12m 57.9s) |   C |   180 | 20.4 |  Coadd 
    1201 | 2024-02-04 15:27:09 |        MASTER-Tunka | (06h 45m 44.01s , -03d 12m 54.0s) |   C |    60 | 19.8 |        
    1264 | 2024-02-04 15:28:12 |        MASTER-Tunka | (06h 45m 44.05s , -03d 12m 52.5s) |   C |    60 | 19.9 |        
    1327 | 2024-02-04 15:29:15 |        MASTER-Tunka | (06h 45m 44.14s , -03d 12m 50.2s) |   C |    60 | 19.9 |        
    1387 | 2024-02-04 15:29:15 |        MASTER-Tunka | (06h 45m 44.14s , -03d 12m 50.2s) |   C |   180 | 20.4 |  Coadd 
    1454 | 2024-02-04 15:31:22 |        MASTER-Tunka | (06h 45m 44.31s , -03d 12m 46.5s) |   C |    60 | 19.8 |        
    1522 | 2024-02-04 15:32:30 |        MASTER-Tunka | (06h 45m 49.39s , -03d 12m 38.6s) |   C |    60 | 19.9 |        
    1585 | 2024-02-04 15:33:33 |        MASTER-Tunka | (06h 45m 49.44s , -03d 12m 36.0s) |   C |    60 | 20.0 |        
    1645 | 2024-02-04 15:33:33 |        MASTER-Tunka | (06h 45m 49.44s , -03d 12m 36.0s) |   C |   180 | 20.5 |  Coadd 
    1648 | 2024-02-04 15:34:37 |        MASTER-Tunka | (06h 45m 49.50s , -03d 12m 34.2s) |   C |    60 | 20.0 |        
    1712 | 2024-02-04 15:35:40 |        MASTER-Tunka | (06h 45m 49.57s , -03d 12m 32.2s) |   C |    60 | 20.0 |        
    1775 | 2024-02-04 15:36:43 |        MASTER-Tunka | (06h 45m 49.60s , -03d 12m 30.7s) |   C |    60 | 20.0 |        
    1835 | 2024-02-04 15:36:43 |        MASTER-Tunka | (06h 45m 49.61s , -03d 12m 30.8s) |   C |   180 | 20.5 |  Coadd 
    1838 | 2024-02-04 15:37:46 |        MASTER-Tunka | (06h 45m 49.68s , -03d 12m 29.1s) |   C |    60 | 20.1 |        
    1901 | 2024-02-04 15:38:50 |        MASTER-Tunka | (06h 45m 49.73s , -03d 12m 27.3s) |   C |    60 | 20.0 |        
    1965 | 2024-02-04 15:39:53 |        MASTER-Tunka | (06h 45m 49.77s , -03d 12m 25.3s) |   C |    60 | 20.0 |        
    2028 | 2024-02-04 15:40:56 |        MASTER-Tunka | (06h 45m 49.82s , -03d 12m 23.8s) |   C |    60 | 20.0 |        
    2091 | 2024-02-04 15:41:59 |        MASTER-Tunka | (06h 45m 49.86s , -03d 12m 21.8s) |   C |    60 | 20.0 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240204A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35670
SUBJECT: GRB 240204A: Mondy optical afterglow candidate
DATE:    24/02/04 18:05:52 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (HSE, IKI),  S. Belkin (IKI, HSE) report on behalf of IKI-GRB-FuN:

We observed the field of Swift localization of GRB 240204A (Cenko et al., GCN 35666) which is also detected be GMB/Fermi (Fermi GBM team GCN 35664)  with AZT-33IK telescope of Mondy observatory  starting on  2024-02-04 (UT) 16:05:26. In the first images of 60 s exposure  we detected the object in coordinates of (J2000) 06:56:43.36, +01:01:37.7 with uncertainties of 0.2 arcsec in both coordinates. The position of the object is within XRT afterglow localization (Cenko et al., GCN 35666).  The object is absent in PS1 catalogue. Preliminary photometry of the object is R ~ 20.6 based on USNO-B1.0 (R2) nearby stars.

We suggest the source is an afterglow of GRB 240204A.


GRB_name: GRB240204A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35671
SUBJECT: GRB 240204A: Enhanced Swift-XRT position
DATE:    24/02/04 19:44:55 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1322 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 240204A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 104.18139, +1.02693 which is equivalent
to:

RA (J2000): 06h 56m 43.53s
Dec (J2000): +01d 01' 36.9"

with an uncertainty of 2.5 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB240204A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35673
SUBJECT: GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
DATE:    24/02/05 02:47:44 GMT
FROM:    Ismael Perez-Fournon at Instituto de Astrofisica de Canarias <ipf@iac.es>

I. PÃ©rez-Fournon and F. Poidevin (IAC and ULL) report

We observed the field of GRB 240204A, detected by FERMI GBM (Fermi GBM team, GCN 35664) and by Swift XRT (Cenko et al., GCN 35666), centred at the enhanced Swift-XRT position reported by Beardmore et al. (GCN 35671) with LCOGT 1m telescopes at Sutherland and Teide Observatories. We detect a source, not visible in PanSTARRS imaging, at the position RA (J2000) = 06:56:43.367, Dec (J2000) = +01:01:38.06 (+/- 0.5" in both coordinates). We measure the following magnitudes in SDSS filters: r' = 21.10 +/- 0.15 on 2024-02-04 20:37:30 UT (Sutherland Observatory) and i' = 20.79 +/- 0.15  on 2024-02-04 21:29:56 UT (Teide Observatory), calibrated using the Gaia DR3 synthetic photometry catalog generated from the Gaia BP/RP mean spectra (Gaia Collaboration, 2022), uncorrected for interstellar extinction.

The reported position agrees within the errors with the enhanced Swift-XRT position and with the positions of the optical source detected by Pozanenko et al. (GCN 35670) and Leonini et al. (GCN 35672). 

The flux is clearly decreasing in the red bands.


GRB_name: GRB240204A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35677
SUBJECT:  GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
DATE:    24/02/05 18:30:30 GMT
FROM:    Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy - MPC Code C82 <osservatorionastroverde@gmail.com>

Nello Ruocco at Osservatorio Nastro Verde - Sorrento (Naples) - Italy
in a large collaboration with:
M.G. Dainotti (National Astronomical Observatory of Japan), 
Y. Niino (Tokyo University, Institute of Astronomy), 
K. Kalinowski (Aarhus University, Department of Physics and Astronomy),
B. De Simone (Universita' degli Studi Di Salerno)
report: 

We image the field of GRB 240204A (Swift triggered on the Fermi/GBM, GCN 35664; Cenko et al., GCN 35666; Pozanenko et al., GCN 35670)
with telescope of Nastro Verde Observatory - Sorrento (Naples), Italy. Member of: 
AAVSO - American Association of Variable Star Observers.
UAI/SSV - Unione Astrofili Italiani/sezione stelle variabili.
AstroCampania Associazione

The observations started at 18:16 UT of 2024/02/04, after about 3 hours after the GRB trigger, at the end of twilight
with principal telescope  SC 0.35 f/10 with focal reduced + CCD Sbig ST10 XME
I took 104 image of 60 sec each. All images are unfiltered, calibrated with masterdark and masterflat,stacked with Tycho Tracker and Astrometrica software
We have not detected any clearly visible sources, up to 20th magnitude with clear skies.
   Start T0+                   End T0+         Rlim
18:16:19 UT            21:15:19 UT      19.5

We did not found any optical counterpart in the error box of the XRTcandidate.




Magnitudes were estimated with the Gaia DR2 cat. and 
are not corrected for galactic dust extinction.



The message may be cited.


GRB_name: GRB240205A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35679
SUBJECT: GRB 240205A: Fermi GBM Final Real-time Localization
DATE:    24/02/05 20:37:04 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 20:26:30 UT on 5 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240205A (trigger 728857595.713148 / 240205852).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 300.9, Dec = 20.5 (J2000 degrees, equivalent to J2000 20h 03m, 20d 30'), with a statistical uncertainty of 6.0 degrees.

The angle from the Fermi LAT boresight is 57.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205852/quicklook/glg_skymap_all_bn240205852.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205852/quicklook/glg_healpix_all_bn240205852.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205852/quicklook/glg_lc_medres34_bn240205852.gif


GRB_name: GRB240204A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35680
SUBJECT: GRB 240204A: Fermi GBM Observation
DATE:    24/02/05 21:17:16 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

L. Scotton (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 15:07:38.68 UT on 04 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240204A (trigger 728752063/240204630),
which was also detected by Swift XRT (S. B. Cenko et al. 2024, GCN 35666).
The Fermi GBM on-ground location is consistent with the Swift XRT position.

The angle from the Fermi LAT boresight is 101 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 15.9 s (50-300 keV). The time-averaged spectrum
from T0-6.5 to T0+34.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.03 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 84 +/- 2 keV.

The event fluence (10-1000 keV) in this time interval is
(1.69 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+12 s in the 10-1000 keV band is 32.9 +/- 0.5 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 79 +/- 2 keV, alpha = -0.97 +/- 0.04 and beta = -3.0 +/- 0.2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240205B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35682
SUBJECT: GRB 240205B: Fermi GBM Final Real-time Localization
DATE:    24/02/05 22:23:35 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 22:13:08 UT on 5 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240205B (trigger 728863993.169242 / 240205926).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 352.0, Dec = -53.0 (J2000 degrees, equivalent to J2000 23h 27m, -53d 00'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 110.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205926/quicklook/glg_skymap_all_bn240205926.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205926/quicklook/glg_healpix_all_bn240205926.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240205926/quicklook/glg_lc_medres34_bn240205926.gif


GRB_name: GRB240205B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35683
SUBJECT: GRB 240205B: Swift detection of a burst
DATE:    24/02/05 22:31:07 GMT
FROM:    David Palmer at LANL <palmer@lanl.gov>


M. J. Moss (GSFC), C. Gronwall (PSU), J.D. Gropp (PSU),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 22:13:06 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240205B (trigger=1213095).  Swift did not immediately slew
due to a Sun constraint. 
The BAT on-board calculated location is 
RA, Dec 351.476, -55.132 which is 
   RA(J2000) = 23h 25m 54s
   Dec(J2000) = -55d 07' 55"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve is only available
up to T+8s due to a telemetry gap. The partial light curve shows a
complex rise to a count rate of ~10,000 counts/s (15-350 keV)
and still rising steeply at 8 sec after the trigger. 

This GRB is Sun constrained for Swift observations until February 25th. 
There will therefore not be any XRT or UVOT data collected. 

Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240205B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35684
SUBJECT: GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
DATE:    24/02/05 23:02:28 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V.Lipunov, Ya.Kechin, N.Tiurina, G.Antipov E.Gorbovskoy (Lomonosov MSU), D.Buckley (SAAO),
D.Svinkin (Ioffe Institute, Konus-Wind),
Ya.Kechin, K.Zhirkov, A.Kuznetsov, D.Vlasenko, P.Balanutsa, Yu.Tselik, N.Tiurina, I.Gorbunov, V.Vladimirov,
D.Zimnukhov, V.Senik, A.Yudin,A.Chasovnikov, D.Cheryasov, A.Sosnovskij (Lomonosov  MSU,SAI,PhysicsDepartment),
O.A. Gres, N.M. Budnev (Irkutsk State University, API),
C.Francile.  F. Podesta, R.Podesta (Observatorio Astronomico Felix Aguilar OAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)

MASTER Global robotic net (http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L) started Swift GRB 240205B/Fermi GRB 240205B observation 26 sec after notice time and 47 sec after trigger time at 2024-02-05 22:13:54 UT, with upper limit up to 15.9 mag. The observations began at zenith distance = 86 deg. (Lipunov et al. GCN 35681) MASTER auto-detection system discovered changing OT inside Swift BAT (Moss GCN 35682, Fermi GCN 25682)
MASTER OT J232550.14-550704.6
R.A.,Dec(2000)=23 25 50.14 -55 07 04.6 with mOT~12.8 near maximum


GRB_name: GRB240205B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35686
SUBJECT: GRB 240205B: BOOTES-7 optical afterglow follow-up
DATE:    24/02/06 01:23:45 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>

E. Fernandez-Garcia, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia, S.-Y. Wu, S. Guziy  (IAA-CSIC Granada), Y.-D. Hu (INAF-OAB, Brera), L. Hernandez-Garcia (Univ. de Valparaiso), C. Perez del Pulgar, A. Castellon, A. Reina (Univ. de Malaga), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), report:

Following the detection of GRB 240205B by Fermi (GCNC 35682) and Swift (Palmer et al., GCNC 35683), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) pointed to the burst position starting on Feb 6 at 00:15 UT (i.e. ~2 h after trigger). Images are being gathered, through passing clouds, in different optical bands (griz). In any case, the optical afterglow reported by MASTER (Lipunov et al. GCNC 35684), is well detected in all images, for which we measure a g-band mag of 15.5 +/- 0.1 (on a 60s image taken at 00:33 UT). Spectroscopic observations are encouraged.

We thank the staff at San Pedro de Atacama Celestial Explorations observatory for their excellent support.


GRB_name: GRB240205B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35687
SUBJECT: GRB 240205B: Skynet Optical Afterglow Observations
DATE:    24/02/06 02:25:46 GMT
FROM:    Dylan Dutton at UNC Chapel Hill <ddutton59@gmail.com>

Dylan Dutton, Donovan Schlekat, Logan Selph, Ruide Fu, Megan Dubay, Daniel Reichart, Joshua Haislip, Vladimir Kouprianov report on behalf of the Skynet Robotic Telescope Network at the University of North Carolina at Chapel Hill.

We observed the field of GRB 240205B with our 0.4m robotic telescopes located in the Cerro Tololo Inter-American Observatory, Chile. The observation began at 00:42:54 UTC on Feb 05 2024, approximately 2.5 hours after the trigger reported by Fermi (GCN 35682) and SWIFT (Palmer et al., GCN 35683).

We obtained multiple exposures in the B, V, R, and I filters. Exposure lengths were calculated using our automated exposure length scaling model.

We clearly detect the optical afterglow reported by MASTER (Lipunov et al., GCN 35684) and BOOTES-7 (GCN 35686). The coordinates are within the uncertainty radius of the Swift localization and consistent with the coordinates reported by MASTER (Lipunov et al., GCN 35684):
R.A. (J2000): 23:25:50.12
Dec. (J2000): -55:07:05.5

We report the photometry below. We estimate a spectral index of -1.

ExpLen | Filter | Mag   | Mag Error  | MJD         
------------------------------------------------
223.98 | B      | 16.12 | 0.017      | 60346.030
284.45 | B      | 16.12 | 0.017      | 60346.031
233.30 | V      | 15.74 | 0.009      | 60346.032
100.85 | R      | 15.49 | 0.010      | 60346.034
298.28 | V      | 15.86 | 0.009      | 60346.035
145.94 | R      | 15.66 | 0.011      | 60346.048
265.82 | B      | 16.31 | 0.012      | 60346.049
113.75 | I      | 15.33 | 0.019      | 60346.049
272.02 | V      | 15.94 | 0.008      | 60346.052
131.13 | R      | 15.76 | 0.010      | 60346.065
391.41 | V      | 16.11 | 0.008      | 60346.065

Our images have been calibrated using stars from the APASS catalog.


GRB_name: GRB240204A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35688
SUBJECT: GRB 240204A: Swift-BAT refined analysis
DATE:    24/02/06 02:39:23 GMT
FROM:    Sibasish Laha at GSFC <sibasish.laha@nasa.gov>

T. Sakamoto (AGU),S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Swift-BAT triggered on GRB 240204A at 15:07:50.63 UT on 2024-02-04.
Swift slewed immediately, but didnâ€™t have initial BAT information due to a telemetry gap.
Using the data set from T-239 to T+346 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240204A (trigger #1212898)
(Cenko, et al., GCN Circ. 35666).  The BAT ground-calculated position is
RA, Dec = 104.290, 1.078 deg which is
   RA(J2000)  =  06h 57m 09.6s
   Dec(J2000) = +01d 04' 41.5"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 9%.

The BAT  light curve shows a complex structure with a duration of ~ 20 sec.
T90 (15-350 keV) is 18.93 +- 2.06 sec (estimated error including systematics).

The time-averaged spectrum from T-22.96 to T+8.96 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.21 +- 0.28,
and Epeak of 67.8 +- 12.6 keV (chi squared 41.34 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.0 +- 0.0 x 10^-05 erg/cm2
and the 1-sec peak flux measured from T+0.08 sec in the 15-150 keV band is
22.1 +- 1.5 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.80 +- 0.06 (chi squared 55.74 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1212898/BA/


GRB_name: GRB240205B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35689
SUBJECT: GRB 240205B: GECAM detection of a long burst 
DATE:    24/02/06 03:12:10 GMT
FROM:    wenlongzhang2018@163.com

Wen-Long Zhang, Shao-Lin Xiong, Chen-Wei Wang report on behalf of the GECAM team:

GECAM-B was triggered in-flight by a long burst, GRB 240205B, at 2024-02-05T22:13:08.400 UTC (T0), which was also detected by Fermi/GBM (GCN #35682), Swift/BAT (GCN #35683), INTEGRAL_SPIACS (trig# 10513) and CALET/GBM (trig# 1391206207). As the science data arrived, GECAM-B was also triggered on-ground by this burst with the automatic processing pipeline. 

According to the GECAM-B light curves, this burst shows multi-pulses with a total duration of ~50 sec. Interestingly, we note that there is a bright and narrow peak at T0+ 37.5 s.

According to the in-flight software, GECAM-B localized this burst to the following position (J2000): 
Ra: 344.14 deg    
Dec: -53.02 deg
Err: 8.74 deg (1-sigma, statistical only)
This GECAM-B localization is consistent with that of Swift/BAT and Fermi/GBM within the error.

We note that these results are very preliminary. Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in December 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).


GRB_name: GRB240204A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35690
SUBJECT: GRB 240204A : OHP/T193/T120 optical afterglow fading detection
DATE:    24/02/06 05:05:24 GMT
FROM:    Christophe Adami at LAM <christophe.adami@lam.fr>

C. Adami, D. Russeil, H. LeCoroller (PythÃ©as/LAM), E. Abdo, M. Carta, T. Chehab, M. Colliaux, A. Gharibi-Ziarati, E. Pouyer, 
A. Jacquet, F. Malaval, S. Aftis (AMU),  J. Balcaen, Y. Degot-Longhi, (OHP/PythÃ©as), E. Le Floc'h, D. GÃ¶tz, F. SchÃ¼ssler (CEA 
Paris-Saclay), B. Schneider (MIT), S. Basa (Pytheas/OHP/LAM), A. Saccardi, S. D. Vergani (GEPI, Obs. de Paris),
M. Dennefeld (IAP), report on behalf of a larger collaboration

We observed the field of GRB 240204A (Fermi-GBM team GCN 35664, Cenko et al. GCN 35666, Pozanenko et al. GCN 35670, 
Leonini et al. GCN 35672, PÃ©rez-Fournon et al. GCN 35673, Dainotti et al. GCN 35677, Bochenek et al. GCN 35678) using the 
T193cm telescope equiped with the MISTRAL instrument and with the T120cm telescope at Observatoire de Haute-Provence 
(France). On the night of 04 February 2024, we made 9 sets of observations with MISTRAL in r band (30min each) and two sets 
of observations with the T120 telescope (V and i bands: 135min each). On the night of 05 February 2024, we made an 
additional single set of observations with MISTRAL in r band during 97.5min. Details are given in the table below.

All magnitudes were calibrated against the PanStarrs catalog (mean Kron magnitudes), extracted in a radius of 1arcmin around 
the GRB position. Magnitudes were not corrected for galactic extinction.

Our results in r-band show a fading behaviour of typically 0.09+/-0.03 mag/hour over the 10 first hours and of 0.06+/-0.01 mag/hours over the 31 first hours.

-----------------------------------------------
T-T0 (in hours) | mag | filter | Telescope
-----------------------------------------------
+4.09 | 21.82+/-0.21 | r | MISTRAL@T193
+4.70 | 21.88+/-0.15 | r | MISTRAL@T193
+5.29 | 21.86+/-0.11 | r | MISTRAL@T193
+5.89 | 21.92+/-0.12 | r | MISTRAL@T193
+6.64 | 21.77+/-0.10 | r | MISTRAL@T193
+7.22 | 21.98+/-0.10 | r | MISTRAL@T193
+7.99 | 21.88+/-0.12 | r | MISTRAL@T193
+8.69 | 22.10+/-0.13 | r | MISTRAL@T193
+9.32 | 22.51+/-0.31 | r | MISTRAL@T193
+30.72 | 23.37+/-0.31 | r | MISTRAL@T193
+6.02 | 22.69+/-0.17 | g | T120
+6.02 | 20.33+/-0.13 | i | T120

We acknowledge OHP staff for its excellent support during the AMU M2-Physics 2024 observationnal internship. This work 
received support from the French government under the France2030 investment plan, as part of the initiative dâ€™Excellence 
dâ€™Aix-Marseille UniversitÂ´e- A*MIDEX (AMX-19-IET-008). We were also supported by the IPhU Graduate School program at 
Aix-Marseille University. We also acknowledge the support by Master Erasmus Mundus Europhotonics 
(599098-EPP-1-2018-1-FR-EPPKA1-JMD-MOB) financed by EACEA (European Education and Culture Executive Agency). 


GRB_name: GRB240204A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35691
SUBJECT: GRB 240204A: Mondy optical afterglow observations
DATE:    24/02/06 07:50:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>

S. Belkin (IKI, HSE), N. Pankov (HSE, IKI), E. Klunko (ISTP), A. Pozanenko (IKI)  report on behalf of IKI-GRB-FuN:

We observed the GRB 240204A  (Fermi-GBM team GCN 35664, Cenko et al. GCN 35666, Pozanenko et al. GCN 35670, Leonini et al. GCN 35672, PÃ©rez-Fournon et al. GCN 35673, Dainotti et al. GCN 35677, Bochenek et al. GCN 35678; Adami et al. GCN 35690)  with AZT-33IK telescope of Mondy observatory  starting on 2024-02-04 (UT) 16:05:26 and  2024-02-05 (UT) 13:10:09. Preliminary photometry of the afterglow  based on USNO-B1.0 (R2) nearby stars is following

Date  UT start t-T0  Filter Exp. OT Err. UL(3sigma)
    (mid, days)  (s)

2024-02-04 16:05:26  0.04292 R 480  19.90 0.10 21.9
2024-02-04 16:13:26  0.04847 R 480  20.01 0.11 21.8
2024-02-04 16:21:26  0.05403 R 480  19.93 0.10 21.9
2024-02-04 16:29:27  0.05959 R 480  19.85 0.09 21.8
2024-02-04 17:31:00  0.11345 R 2400 20.55 0.10 22.5
2024-02-05 13:10:09  0.96772 R 8400 22.4  0.2  23.1


GRB_name: GRB240204A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35692
SUBJECT:  GRB 240204A: AstroSat CZTI detection
DATE:    24/02/06 14:39:17 GMT
FROM:    Varun Bhalerao at IIT Bombay <varunb@iitb.ac.in>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240204A which was also detected by Fermi-GBM (Fermi GBM Team, GCN Circ. 35664), and Swift (Cenko et al., GCN Circ. 35666).

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2024-02-04 15:07:49.50 UTC. The measured peak count rate associated with the burst is 201 (+40 -25) counts/s above the background in the combined data of four quadrants, with a total of 1125 (+193 -176) counts. The local mean background count rate was 308 (+5 -6) counts/s. Using cumulative rates, we measure a T90 of 10.5 (+1.1 -2.5) s.

The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-02-04 15:07:49.4 UTC. The measured peak count rate associated with the burst is 388 (+65, -60) counts/s above the background in the combined data of all quadrants, with a total of 2008 (+336, -351) counts. The local mean background count rate was 1276 (+6, -6) counts/s. We measure a T90 of 8.5 (+3.1, -2.1) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240205B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35693
SUBJECT: GRB 240205B: Fermi GBM Observation
DATE:    24/02/06 15:05:19 GMT
FROM:    Cori Fletcher at USRA <cfletcher@usra.edu>

C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 22:13:08.17 UT on 05 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240205B (trigger 728863993/240205926).
which was also detected by Swift BAT (M. J. Moss et al. 2024, GCN 35683) and GECAM (W. Zhang et al. 2024, GCN 35689).
The Fermi GBM Real-time Final Localization (GCN 35682) is consistent with the Swift BAT position.

This burst was also independently detected by INTEGRAL SPI-ACS.

The angle from the Fermi LAT boresight is 112 degrees.

The GBM light curve consists of multiple peaks with a duration (T90)
of about 47 s (50-300 keV). The time-averaged spectrum
from T0-3.3 to T0+54.0 s is best fit by
a Band function with Epeak = 34 +/- 0.8 keV,
alpha = -1.69 +/- 0.02, and beta = -2.78 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(4.77 +/- 0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+38 s in the 10-1000 keV band is 81.2 +/- 0.9 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240205B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35694
SUBJECT: GRB 240205B: REM detection of the optical/NIR afterglow
DATE:    24/02/06 16:33:01 GMT
FROM:    Matteo Ferro <matteo.ferro@inaf.it>

M. Ferro, R. Brivio, Y.-D. Hu, P. D'Avanzo, D. Fugazza, S. Covino (INAF-OAB) on behalf of the REM team, report:

We observed the field of GRB 240205B (Fermi GBM Team., GCN 35682; Moss et al., GCN 35683) with the REM 60cm robotic telescope located at the ESO Observatory of La Silla (Chile). The observations were carried out in the g, r, i, z, J, H and K bands, starting on 2024 Feb 05 at 00:46:23 UT (i.e. about 2.55 hours after the GBM and Swift trigger) and lasted for about 1.5 hours.

The optical (Lipunov et al., GCN 35684, Fernandez-Garcia et al., GCN 35686, Dutton et al., GCN 35687) and NIR afterglow is detected in our observations. From preliminary photometry, we derive the following magnitudes, in r and H bands:

r = 15.67+/-0.01 (AB; calibrated against SkyMapper catalogue)
at a mid time of t-t0 ~ 2.63 hours after the GRB trigger.
H = 13.92+/-0.04 (Vega; calibrated against the 2MASS catalogue)
at a mid time of t-t0 ~ 2.65 hours after the GRB trigger.


GRB_name: GRB240205B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35696
SUBJECT: GRB 240205B: BOOTES-6 optical afterglow follow-up
DATE:    24/02/06 23:51:09 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct@iaa.es>

E. Fernandez-Garcia, I. Perez-Garcia, M.D. Caballero-Garcia, S. Guziy, S.-Y. Wu, I. Olivares, R. Sanchez-Ramirez and A. J. Castro-Tirado (IAA-CSIC, Granada), Y.-D. Hu (INAF-OAB Brera), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), A. Castellon, S. Castillo, A. J. Reina and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report:

Following the detection of GRB 240205B by Fermi (GCNC 35682, Fletcher et al. GCNC 35693), Swift (Palmer et al., GCNC 35683), INTEGRAL_SPIACS (trig# 10513), CALET/GBM (trig# 1391206207) and GECAM (Zhang et al., GCNC 35689), the 0.6m BOOTES-6/DPR robotic telescope at Boyden Observatory (South Africa) continued the observation of this burst, starting on Feb 6 at 18:13 UT (i.e. ~20 h after trigger), as part of the monitoring conducted by the BOOTES Global Network of Robotic Telescopes. Images were gathered in different optical bands (griz). The optical afterglow (Lipunov et al. GCNC 35684, Fernandez-Garcia et al. GCNC 35686, Dutton et al. GCNC 35687, Ferro et al. GCNC 35694) is still detected in all filters. We measure a g-band mag of 18.1 Â± 0.1 (on a 300s image taken at 18:30 UT). Spectroscopic observations, in spite of the low elevation of the target after sunset, are encouraged.

We thank the staff at Boyden Observatory for their excellent support.


GRB_name: GRB240205B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35697
SUBJECT: GRB 240205B: CALET Gamma-Ray Burst Monitor detection
DATE:    24/02/07 01:32:14 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

T. Sakamoto, A. Yoshida, S. Sugita (AGU), Y. Kawakubo (LSU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 240205B (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 35682; Swift detection: Moss et al.,
GCN Circ. 35683; INTEGRAL SPI-ACS Trigger #10513; GECAM 
detection: Zhang et al., GCN Circ. 35689;  Fermi GBM Observation:
Fletcher et al., GCN Circ. 35693) triggered the CALET Gamma-ray 
Burst Monitor (CGBM) at 22:13:45.98 UTC on 5 February 2024
(http://cgbm.calet.jp/cgbm_trigger/flight/1391206207/).
The burst signal was seen by only the SGM detector.

Based on the GRB position reported by Swift-BAT (referenced to
GCN Circ. 35683), the angle from the SGM bore-sight is 106 
degrees, and the direction was blocked by the structures of the 
International Space Station.  Although the observed light curve was
affected by the structures, SGM detected the brightest peak which
was observed by Fermi-GBM, INTEGRAL SPI-ACS, and GECAM.

The burst light curve shows a single pulse that starts at T+0.0 sec, 
peaks at T+0.4 sec, and ends at T+0.9 sec. The T90 and T50 durations 
measured by the SGM data are 0.7 +/- 0.3 sec and 0.2 +/- 0.1 sec 
(40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1391206207/index.html

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB240205B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35698
SUBJECT: GRB 240205B: VLT/X-shooter redshift
DATE:    24/02/07 11:08:25 GMT
FROM:    J. T. Palmerio at Observatoire de Paris - GEPI <jesse.palmerio@obspm.fr>

H. Fausey (GWU), J. T. Palmerio (GEPI/Obs. de Paris & IAP), D. B. Malesani (DAWN/NBI & Radboud Univ.), A. Saccardi (GEPI/Obs. de Paris), L. Izzo (INAF-OACn & DARK/NBI), V. D'Elia (SSDC & INAF-OAR), J. P. U. Fynbo (DAWN/NBI), A. Martin-Carrillo (UCD, Ireland), A. J. Levan (Radboud), N. R. Tanvir (U. Leicester), B. Gompertz (Birmingham) report on behalf of the Stargate collaboration:

We observed the field of GRB 240205B detected by Fermi-GBM (Fermi GBM Team, GCN 35682), Swift-BAT (Moss et al., GCN 35683), and GECAM (Zhang et al., GCN 35689) using the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Our spectra cover the wavelength range 3000-21000 AA, and consist of 2 exposures of 600 s each. The observation starting-time was 00:21:26 UT on 2024 Feb 7 (~26 hr after the trigger). Observations were carried out in twilight, at high airmass 2.3 to 2.5.

Despite the low elevation, in a single r-band image taken with the acquisition camera, we clearly detect the optical afterglow (Lipunov et al., GCN 35684; Fernandez-Garcia et al., GCN 35686; Dutton et al., GCN 35687; Ferro et al., GCN 35694; Fernandez-Garcia et al., GCN 35696). We measure r' = 19.05 +/- 0.07 (AB) calibrated against two nearby SkyMapper stars.

In a preliminary reduction of the spectra, we detect a continuum down to at least 3200 AA implying z < 1.6 from the lack of damped Lyman-alpha absorption. Multiple absorption features are detectd, consistent with being due to Fe II and Mg II at a common redshift z = 0.824. While the modest S/N does not allow to identify any fine-structure lines at this redshift, due to the lack of unidentified features we consider z = 0.824 the likely redshift of GRB 240205B.

We acknowledge the excellent support from the ESO staff in Paranal in conducting such a challenging observation, in particular Boris Haeussler, Zahed Wahhaj, and Diego Parraguez.


GRB_name: GRB240125A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35699
SUBJECT: Konus-Wind detection of GRB 240125A
DATE:    24/02/07 14:51:18 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short-duration GRB 240125A
(Glowbug gamma-ray detection: Cheung et al., GCN 35630;
AstroSat CZTI detection: Joshi et al., GCN 35637;
CALET CGBM detection: Marrocchesi et al., GCN 35639;
GRBAlpha detection: Dafcikova et al., GCN 35645;
IPN triangulation: Kozyrev et al., GCN 35652)
triggered Konus-Wind at T0=34503.601 s UT (09:35:03.601).

The burst light curve shows a multipeaked structure
which starts at ~T0-0.5 s and has a total duration of ~1.0 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240125_T34503/

As observed by Konus-Wind, the burst
had a fluence of 4.79(-1.52,+5.06)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.220 s,
of 1.13(-0.57,+1.27)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.512 s to T0+0.448 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = 0.01(-0.59,+1.53) and Ep = 982(-418,+1876) keV.

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240207A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35700
SUBJECT: GRB 240207A: Fermi GBM Final Real-time Localization
DATE:    24/02/07 15:30:53 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 15:20:18 UT on 7 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240207A (trigger 729012023.222884 / 240207639).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 162.1, Dec = 51.6 (J2000 degrees, equivalent to J2000 10h 48m, 51d 36'), with a statistical uncertainty of 9.2 degrees.

The angle from the Fermi LAT boresight is 73.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240207639/quicklook/glg_skymap_all_bn240207639.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240207639/quicklook/glg_healpix_all_bn240207639.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240207639/quicklook/glg_lc_medres34_bn240207639.gif


GRB_name: GRB240205B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35701
SUBJECT: Konus-Wind detection of GRB 240205B (long / very soft)
DATE:    24/02/07 17:14:19 GMT
FROM:    Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>

D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long GRB 240205B (Fermi GBM observation:
Fermi GBM team, GCN 35682; Fletcher et al., GCN 35693;
Swift detection: Moss et al., GCN 35683;
GECAM detection: Zhang et al., GCN 35689;
CALET detection: Sakamoto et al., GCN 35697)
triggered Konus-Wind (KW) at T0=79986.680 s UT (22:13:06.680).

The burst light curve shows multiple overlapping pulses
in the interval from ~T0-5 s to ~T0+57 s,
with the brightest peak around ~T0+36 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240205_T79986/

As observed by Konus-Wind, the burst had
a total fluence of (3.22 Â± 0.18)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0+36.352 s,
of (7.38 Â± 0.87)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

A time-integrated spectrum (measured from T0 to T0+49.408 s)
is best fit in the 20 keV - 1.5 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.80 (-0.08,+0.09),
the high energy photon index beta = -3.20 (-6.80,+0.35),
the peak energy Ep = 27 (-16,+10) keV,
chi2 = 28/49 dof.

A spectrum near the peak count rate (measured from T0+33.024 to T0+41.216 s)
is best fit in the 20 keV - 15 MeV range by a CPL model
with alpha = -1.70(-0.10,+0.11) and Ep = 49(-10,+8) keV (chi2 = 64/62 dof).
Fitting this spectrum by a Band function yields the same values of alpha and Ep,
and an upper limit on the high energy photon index beta of -3.5 (chi2 = 64/62 dof).

Assuming the redshift z=0.824 (Fausey et al., GCN 35698)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the burst isotropic energy release E_iso to (6.1 Â± 0.3)x10^52 erg,
the isotropic peak luminosity L_iso to (2.6 Â± 0.5)x10^52 erg/s,
the rest-frame peak energy of the time-integrated spectrum Ep,i,z to ~49 keV,
and the rest-frame peak energy at the peak of the emission Ep,p,z to ~89 keV.
With the obtained estimates, GRB 240205B is a soft-spectrum outlier in
both 'Amati' and 'Yonetoku' relations derived for the sample of >300 long
KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),
see http://www.ioffe.ru/LEA/GRBs/GRB240205_T79986/GRB240205B_rest_frame.pdf


All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB240205B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35702
SUBJECT: GRB 240205B: Swift-BAT refined analysis
DATE:    24/02/07 19:18:03 GMT
FROM:    Sibasish Laha at GSFC <sibasish.laha@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), T. Sakamoto (AGU),
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 240205B (trigger #1213095)
(Moss, et al., GCN Circ. 35683).  The BAT ground-calculated position is
RA, Dec = 351.466, -55.123 deg which is
   RA(J2000)  =  23h 25m 51.9s
   Dec(J2000) = -55d 07' 24.5"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.

The BAT light curve shows a complex structure with a duration of ~ 60 sec.
Above 100 keV, the lightcurve is dominated by a single bright 1 s long peak around T+40.
A similar feature has also been reported by GECAM-B telescope, Zhang et al., GCN circ. 35689.
T90 (15-350 keV) is 47.29 +- 0.29 sec (estimated error including systematics).

The time-averaged spectrum from T-0.84 to T+78.94 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.23 +- 0.03.  The fluence in the 15-150 keV band is 2.6 +- 0.0 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+39.07 sec in the 15-150 keV band
is 47.8 +- 1.0 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1213095/BA/


GRB_name: GRB240205B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35704
SUBJECT: GRB 240205B: AstroSat CZTI detection
DATE:    24/02/08 15:28:38 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com>

J. Joshi (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long-duration GRB 240205B which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35682), Swift-BAT (Moss et al., GCN Circ. 35683), and GECAM (Zhang et al., GCN Circ. 35689).

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-02-05 22:13:46.50 UTC. The measured peak count rate associated with the burst is 731 (+51, -56) counts/s above the background in the combined data of all quadrants, with a total of 3027 (+294, -448) counts. The local mean background count rate was 295 (+3, -2) counts/s. Using cumulative rates, we measure a T90 of 43 (+3, -2) s.

The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-02-05 22:13:45.31 UTC. The measured peak count rate associated with the burst is 632 (+69, -74) counts/s above the background in the combined data of all quadrants, with a total of 2944 (+573, -674) counts. The local mean background count rate was 1220 (+4, -6) counts/s. We measure a T90 of 42 (+2, -3) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB240204A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35705
SUBJECT: GRB240204A: Swift/UVOT Upper Limits
DATE:    24/02/08 15:37:24 GMT
FROM:    Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>

M. H. Siegel (PSU) and and S. B Cenko (GSFC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240204A 
4.8 ks after the BAT trigger (Cenko et al., GCN Circ 35666). No optical
afterglow consistent with either the optical (Pozanenko et al., GCN
Circ. 35670) or X-ray (Beardmore et al., GCN Circ. 35671) position is
detected in the initial UVOT exposures.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures of
the candidate afterglow field are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white             5887         6087          196            >20.70
v                 4862         6498          393            >19.32
b                 5683         5882          196            >19.98
u                 5477        28539         1048            >20.54
uvw1              5272         5472          196            >19.26
uvm2              5067         6669          360            >19.36
uvw2              6093         6293          196            >19.42

The magnitudes in the table are not corrected for the Galactic extinction
due to the high but uncertain reddening in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240205A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35707
SUBJECT: GRB 240205A (short): Glowbug gamma-ray detection
DATE:    24/02/08 21:34:45 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of the short GRB 240205A, which was also detected by Fermi/GBM (GCN 35679) and Konus-Wind (Trigger Time 20:26:26.689).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-05 20:26:29.640 with a duration of 0.29 s and a total significance of about 24.0 sigma.  The light curve comprises a single peak.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.0 and a cutoff energy ("Epeak") of 310 keV.  The modeled 10-10000 keV fluence is 4.2e-07 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240205B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35708
SUBJECT: GRB 240205B: PRIME near infrared detection
DATE:    24/02/08 21:36:03 GMT
FROM:    Joe Durbak at UMD <gcn.joedurbak@gmail.com>

O. Guiffreda (UMD), J. Durbak (UMD), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), K. De (MIT), S. B. Cenko (NASA/GSFC)

Following the FERMI GBM detection (GCN 35682), and Swift BAT detection (Moss et al. GCN 35683), we observed the transient field in the J filter with PRIME ~2 days after FERMI & Swift detection.

At the position of the optical counterpart reported by MASTER (Lipunov et al. GCN 35684) and Skynet (Dutton et al. GCN 35687), we detect an uncatalogued source in J band. Using nearby 2MASS stars for preliminary calibration we derive the following magnitudes, not corrected for Galactic extinction:  

Filter | Mag(AB)        | SNR | Seeing | Total exposure time (s) 
-------|----------------|-----|--------|-------------------------
J      | 19.65 +/- 0.15 |11.8 | 2.138â€ | 800


PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa.

Further observations are planned.

We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations.


GRB_name: GRB240205A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35710
SUBJECT: IPN triangulation of GRB 240205A (short)
DATE:    24/02/09 16:02:13 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,
report:

The short-duration GRB 240205A
(Ferm-GBM detection: The Fermi GBM team, GCN 35679;
Glowbug detection: Cheung, et al.,  GCN 35707)
was detected by Fermi (GBM trigger 728857595), Konus-Wind,
INTEGRAL (SPI-ACS), and Swift (BAT) at about 73591 s UT (20:26:31).
The burst was outside the coded field of view of the BAT.

We have triangulated this GRB to the following annuli:
---------------------------------------------------
annulus          R.A.     Dec.     R     dR (3sigma)
                (deg)    (deg)   (deg)     (deg)
---------------------------------------------------
Konus-GBM     297.778  -19.219  40.665  0.735
GBM-SPI-ACS   180.960   84.546  70.289  6.208
---------------------------------------------------
The annuli intersect to form a long 60.9 sq.deg (3 sigma)
localization region.

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240205_T73586/IPN

The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.


GRB_name: GRB240209A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35712
SUBJECT: GRB 240209A: Fermi GBM Final Localization
DATE:    24/02/09 21:46:46 GMT
FROM:    Christian Malacaria at ISSI <cmalacaria.astro@gmail.com>

The Fermi GBM team reports the detection of a likely LONG GRB.

"At 06:19:19.82 UT on 09 April 2024, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 240209A (trigger 729152364 / 240209263).

The on-ground calculated location, using the GBM trigger data, 
is RA = 259.8, DEC = 70.5 (J2000 degrees, equivalent 
to 17h 19m, 70d 30'), with an uncertainty of 9.1 degrees.

The angle from the Fermi LAT boresight at the GBM trigger time is 31 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240209263/quicklook/glg_skymap_all_bn240209263.png

The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240209263/quicklook/glg_healpix_all_bn240209263.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240209263/quicklook/glg_lc_medres34_bn240209263.gif"


GRB_name: GRB240205A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35713
SUBJECT: Konus-Wind detection of GRB 240205A (short)
DATE:    24/02/11 15:33:36 GMT
FROM:    Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>

D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short-duration GRB 240205A
(Fermi GBM Final Real-time Localization: GCN 35679;
Glowbug gamma-ray detection: Cheung et al., GCN 35707;
IPN triangulation: Svinkin et al., GCN 35710)
triggered Konus-Wind at T0=73586.689 s UT (20:26:26.689).

The burst light curve shows a single pulse,
which starts at ~T0-0.2 s and has a total duration of ~0.45 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240205_T73586/

As observed by Konus-Wind, the burst
had a fluence of 5.45(-0.84,+0.89)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.016 s,
of 4.13(-0.92,+1.08)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the brightest part of the burst emission
was detected before the trigger, the spectral analysis
was performed using the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.192 s to T0+0.256 s)
by a power law with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.10(-0.38,+0.48) and Ep = 241(-46,+52) keV.

Modelling the KW 3-channel spectrum near the peak count rate
(measured from T0-0.064 s to T0) by the CPL model
yields alpha = -0.30(-0.48,+0.64) and Ep = 317(-82,+136) keV.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240204A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35714
SUBJECT: Konus-Wind detection of GRB 240204A
DATE:    24/02/11 19:46:09 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 240204A
(Fermi-GBM detection: The Fermi GBM team, GCN 35664;
Swift-BAt detection: Cenko et al., GCN 35666;
AstroSat-CZTI detection: Joshi et al., GCN 35692)
triggered Konus-Wind at T0=54473.519 s UT (15:07:53.519).

The burst light curve shows a single pulse
which starts at ~T0-4.5 s and has a total duration of ~21.5 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240204_T54473/

As observed by Konus-Wind, the burst
had a fluence of 1.37(-0.07,+0.07)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.448 s,
of 4.22(-1.15,+1.15)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.29(-0.16,+0.17)
and Ep = 81(-6,+6) keV (chi2 = 87/83 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.9
(chi2 = 86/82 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB240209A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35715
SUBJECT: GRB 240209A: GOTO optical counterpart candidate
DATE:    24/02/12 11:09:24 GMT
FROM:    Sergey Belkin at Monash University <sergey.belkin@monash.edu>

S. Belkin, M. Kennedy, B. P. Gompertz, K. Ackley, R. Starling, T. Killestein, M. J. Dyer, J. Lyman, K. Ulaczyk, F. Jimenez-Ibarra, A. Kumar, D. O'Neill, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:

We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 240209A (Fermi GBM team, GCN 35712). Targeted observations were performed by GOTO-North between 05:27:38 on 2024-02-11 (starting 47 hrs after trigger) and 03:58:21 on 2024-02-12. Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).

Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using recent survey observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks.

We identify 1 candidate optical counterpart (GOTO24pw/AT2024cew) within the GBM 90% localisation region. We find no evidence of this source prior to the GRB trigger time in previous GOTO observations, the ZTF observations provided by the Lasair broker (Smith et al. 2019), or the ATLAS forced photometry server (Shingles et al. 2021). The most recent non-detection was taken by ATLAS on 2024-02-01.

Name | RA(J2000) | Dec(J2000) | Filter | t - trig(days) | Mag(AB)
GOTO24pw | 17:01:05.29 | +68:43:46.31 | L | 1.96 | 19.64 +/- 0.14

The source is seen to decay as a power-law with an index of t^-1.80+/-0.16 across 3 epochs of observations. The most recent detection magnitude was L = 20.45 +/- 0.19 at 2.90 days after trigger.

Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction.

We note the presence of the GLADE+ (Dalya et al. 2022) catalogued galaxy HyperLEDA 2722973 (z=0.1629+/-0.0150) approximately 7.3" away. At this redshift the sky-projected offset of the transient from this galaxy is 20.58 kpc. This transient is spatially coincident with the cluster ZwCl 8111.

Observations are ongoing.

GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC).


GRB_name: GRB240209A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35716
SUBJECT: GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
DATE:    24/02/13 17:19:17 GMT
FROM:    Antonio de Ugarte Postigo at OCA <deugarte@oca.eu>

A. de Ugarte Postigo (CNRS/OCA & LAM), D. B. Malesani (DAWN/NBI & Radboud Univ.), M. I. Andersen (NBI), J. Sollerman (SU) report:

We observed AT2024cew / GOTO24pw (Belkin et al. GCN 35715), the optical counterpart candidate of GRB 240209A (Fermi GBM team, GCN 35712), using AlFOSC imaging on the 2.5m Nordic Optical Telescope (NOT), at the Roque de los Muchachos Observatory (La Palma, Spain).

The observation consisted of 5x300 s using r-band filter, with a mean time 3.990 days after the burst. The image shows a strong detection of the proposed counterpart at a preliminary magnitude of r~19.80+/-0.05, as compared to PanSTARRS field stars.

This is brighter than the last reported GOTO magnitude observed a day before, corresponding to a behaviour unlike typical GRB afterglows. However, we do note that there is a difference in the filters that could account for some inconsistency in the magnitudes of the two instruments.

If the object is at the same redshift of the nearby galaxy (photo-z = 0.16), then its absolute magnitude would be M_V ~ -19.9. This would be similar to some luminous supernovae (f.ex. a SN Ia) close to peak light. However, the fast decay and subsequent re-brightening in a day-scale, would be peculiar for a SN near peak.


GRB_name: GRB240209A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35717
SUBJECT: GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
DATE:    24/02/13 18:24:21 GMT
FROM:    Antonio de Ugarte Postigo at OCA <deugarte@oca.eu>

A. de Ugarte Postigo (CNRS/OCA & LAM), M. Bremer (IRAM), C. C. Thoene (ASU-CAS), J. F. Agui Fernandez (CAHA), S. Antier (OCA), S. Basa (LAM), M. Michalowski (AOI-AMU), D. A. Perley (LJMU), S. Martin (ESO, ALMA) report:

We observed AT2024cew / GOTO24pw (Belkin et al. GCN 35715, de Ugarte Postigo et al. GCN 35716), the optical counterpart candidate of GRB 240209A (Fermi GBM team, GCN 35712), with NOEMA at 74 and 90 GHz at a mean epoch 4.025 days after the burst.

There is no detection down to a 3-sigma limit of 60 microJy at 90 GHz. This limit disfavours the connection between AT2024cew / GOTO24pw and GRB 240209A, although it is not excluding.

Based on observations carried out under project number W23DI with the IRAM NOEMA Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).


GRB_name: GRB240213A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35718
SUBJECT: GRB 240213A: Fermi GBM Final Real-time Localization
DATE:    24/02/13 20:32:08 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 20:11:09 UT on 13 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240213A (trigger 729547874.78288 / 240213841).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 166.4, Dec = -20.5 (J2000 degrees, equivalent to J2000 11h 05m, -20d 30'), with a statistical uncertainty of 1.6 degrees.

The angle from the Fermi LAT boresight is 112.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240213841/quicklook/glg_skymap_all_bn240213841.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240213841/quicklook/glg_healpix_all_bn240213841.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240213841/quicklook/glg_lc_medres34_bn240213841.gif


GRB_name: GRB240213A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35719
SUBJECT: Fermi GRB 240213A: Global MASTER-Net observations report
DATE:    24/02/13 20:46:19 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 240213A ( Fermi GBM team, GCN 35718) errorbox  547 sec after notice time and 581 sec after trigger time at 2024-02-13 20:20:50 UT, with upper limit up to  15.4 mag. The observations began at zenith distance = 83 deg. The sun  altitude  is -23.7 deg. 

MASTER-SAAO robotic telescope  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240213A errorbox  564 sec after notice time and 598 sec after trigger time at 2024-02-13 20:21:08 UT, with upper limit up to  19.5 mag. The observations began at zenith distance = 53 deg. The sun  altitude  is -31.8 deg. 

MASTER-Tunka robotic telescope  located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 240213A errorbox  841 sec after notice time and 875 sec after trigger time at 2024-02-13 20:25:45 UT, with upper limit up to  18.8 mag. The observations began at zenith distance = 75 deg. The sun  altitude  is -37.2 deg. 

The galactic latitude b = 36 deg., longitude l = 273 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2377781

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     641 | 2024-02-13 20:20:50 |         MASTER-Amur | (11h 07m 11.98s , -20d 31m 49.5s) |   C |   120 | 15.4 |        
     628 | 2024-02-13 20:21:08 |         MASTER-SAAO | (11h 06m 57.05s , -20d 30m 53.7s) |   C |    60 | 19.5 |        
     628 | 2024-02-13 20:21:08 |         MASTER-SAAO | (11h 01m 26.58s , -20d 19m 25.9s) |   C |    60 | 19.4 |        
     708 | 2024-02-13 20:22:27 |         MASTER-SAAO | (11h 06m 56.96s , -20d 30m 52.9s) |   C |    60 | 19.5 |        
     708 | 2024-02-13 20:22:27 |         MASTER-SAAO | (11h 01m 26.50s , -20d 19m 25.2s) |   C |    60 | 19.4 |        
     791 | 2024-02-13 20:23:10 |         MASTER-Amur | (11h 07m 14.59s , -20d 30m 39.0s) |   C |   140 | 15.4 |        
     788 | 2024-02-13 20:23:47 |         MASTER-SAAO | (11h 06m 56.88s , -20d 30m 52.3s) |   C |    60 | 19.3 |        
     788 | 2024-02-13 20:23:47 |         MASTER-SAAO | (11h 01m 26.41s , -20d 19m 24.9s) |   C |    60 | 19.4 |        
     906 | 2024-02-13 20:25:45 |        MASTER-Tunka | (11h 05m 09.88s , -20d 06m 52.1s) |   C |    60 | 18.4 |        
     966 | 2024-02-13 20:25:45 |        MASTER-Tunka | (11h 05m 09.88s , -20d 06m 52.1s) |   C |   180 | 18.8 |  Coadd 
     965 | 2024-02-13 20:25:50 |         MASTER-Amur | (11h 07m 07.90s , -20d 31m 27.1s) |   C |   170 | 15.1 |        
     969 | 2024-02-13 20:26:48 |        MASTER-Tunka | (11h 05m 10.00s , -20d 06m 51.6s) |   C |    60 | 18.4 |        
    1032 | 2024-02-13 20:27:51 |        MASTER-Tunka | (11h 05m 10.11s , -20d 06m 51.4s) |   C |    60 | 18.3 |        
    1095 | 2024-02-13 20:28:55 |        MASTER-Tunka | (11h 05m 10.20s , -20d 06m 50.6s) |   C |    60 | 18.2 |        
    1155 | 2024-02-13 20:28:55 |        MASTER-Tunka | (11h 05m 10.19s , -20d 06m 50.7s) |   C |   180 | 18.8 |  Coadd 
    1160 | 2024-02-13 20:29:00 |         MASTER-Amur | (11h 07m 07.37s , -20d 30m 33.7s) |   C |   180 | 14.3 |        
    1159 | 2024-02-13 20:29:58 |        MASTER-Tunka | (11h 05m 10.31s , -20d 06m 50.4s) |   C |    60 | 18.3 |        
    1222 | 2024-02-13 20:31:01 |        MASTER-Tunka | (11h 05m 10.38s , -20d 06m 49.8s) |   C |    60 | 18.3 |        
    1360 | 2024-02-13 20:32:19 |         MASTER-Amur | (11h 07m 11.73s , -20d 31m 38.6s) |   C |   180 | 14.0 |        
    1349 | 2024-02-13 20:33:08 |        MASTER-Tunka | (11h 05m 10.60s , -20d 06m 48.8s) |   C |    60 | 18.3 |        
    1409 | 2024-02-13 20:33:08 |        MASTER-Tunka | (11h 05m 10.59s , -20d 06m 48.6s) |   C |   180 | 18.7 |  Coadd 
    1412 | 2024-02-13 20:34:11 |        MASTER-Tunka | (11h 05m 10.65s , -20d 06m 48.8s) |   C |    60 | 18.3 |        
    1559 | 2024-02-13 20:35:38 |         MASTER-Amur | (11h 07m 06.10s , -20d 32m 41.8s) |   C |   180 | 13.6 |        
    1544 | 2024-02-13 20:36:23 |        MASTER-Tunka | (11h 05m 11.14s , -20d 05m 45.1s) |   C |    60 | 18.1 |        
    1670 | 2024-02-13 20:38:29 |        MASTER-Tunka | (11h 05m 11.38s , -20d 05m 44.6s) |   C |    60 | 18.5 |        
    1733 | 2024-02-13 20:39:33 |        MASTER-Tunka | (11h 05m 11.46s , -20d 05m 44.6s) |   C |    60 | 18.5 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240213A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35720
SUBJECT: GRB 240213A: BALROG localization (Fermi Trigger  / GRB 240213841)
DATE:    24/02/13 20:59:44 GMT
FROM:    Jochen Greiner at MPE <jcgrog@mpe.mpg.de>

T. Preis, B. Biltzinger, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
 at 20:11:09 on 13 Feb. 2024 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position is:
RA(2000.0) = 166.0 deg
Decl.(2000.0) = -18.3 deg
The 1 sigma statistical error radius is 3.1 deg.
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB240213841/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB240213841/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB240213841/json

                        


GRB_name: GRB240214A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35722
SUBJECT: GRB 240214A: Tiled Swift observations
DATE:    24/02/14 07:22:27 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>


P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 240214A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00122

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240128A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35723
SUBJECT: GRB 240128A: Further Swift-XRT observations
DATE:    24/02/14 07:52:22 GMT
FROM:    Paolo D'Avanzo at INAF-OAB <pda.davanzo@gmail.com>

P. D'Avanzo (INAF-OAB), K.L. Page (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Swift-XRT has performed further follow-up observations of the MAXI-detected burst GRB 240128A (Yamaoka et al., GCN Circ. 35646; 
Yoshida et al., GCN Circ. 35647; Dafcikova et al., GCN Circ. 35649; Cheung et al., GCN Circ. 35651). The data were collected between T0+553.6 ks and T0+1237.1 ks, and are entirely in Photon Counting (PC) mode for a total exposure time of 8.0 ks. 

The uncatalogued X-ray source reported by Perri et al. ("Source 1"; GCN Circ. 35650), is still detected at an average count rate of 
~ 4e-2 ct/s and shows no definitive signs of fading. Therefore, we conclude that it is likely a field source unrelated with the GRB. 

The results of the XRT-team automatic analysis of the XRT observations for this GRB, including a position-specific upper limit calculator, 
are available at https://www.swift.ac.uk/xrt_products/TILED_GRB00120 <https://www.swift.ac.uk/xrt_products/TILED_GRB00120>.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240213A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35728
SUBJECT: GRB 240213A: Glowbug gamma-ray detection
DATE:    24/02/14 21:26:45 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:
 
The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240213A, which was also detected by Fermi/GBM (GCN 35718, 35720).
 
Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-13 20:11:08.016 with a duration of 46.1 s and a total significance of about 130 sigma.  The light curve comprises a multi-peaked structure similar to that observed by Fermi/GBM.
 
Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=1.1 and a cutoff energy ("Epeak") of 223 keV.  The modeled 10-10000 keV fluence is 1.5e-05 erg/cm^2.
 
The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.
 
Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.
 
[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006
 
Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240209A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35729
SUBJECT: GRB 240209A: Fermi GBM observation
DATE:    24/02/14 21:34:38 GMT
FROM:    Christian Malacaria at ISSI <cmalacaria.astro@gmail.com>

C. Malacaria (ISSI) reports on behalf of the Fermi GBM Team:

"At 06:19:19.82 UT on 09 February 2024, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 240209A (GCN #35712). 
A GOTO optical counterpart candidate was found 
within the GBM 90% localisation region (GCN #35715), at a nominal 
angular separation from the GBM on-ground localisation of 2.4 degrees.
Additional observations of the GOTO candidate 
were reported in GCN #35716, #35717, #35724, #35725.

Careful inspection of the GBM trigger by the Fermi-GBM Team identified 
a weak, soft GRB.
The GBM light curve consists of a single pulse with a duration (T90)
of about 5.4 s (50-300 keV). The time-averaged spectrum from 
T0-4.0 s to T0+0.0 s is best fit by a power law function with 
index of -1.82 +/- 0.07 

A power law function with an exponential high-energy cutoff with 
alpha = -1.4 +/- 0.2 and Epeak = 107 +/- 40 keV,
fits the spectrum equally well.

The event fluence (10-1000 keV) in this time interval is
(7.0 +/- 0.8)E-07 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0-1.98 s in the 10-1000 keV band
is 3.0 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB240209A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35730
SUBJECT: GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
DATE:    24/02/14 22:00:51 GMT
FROM:    kendall.ackley@warwick.ac.uk

K. Ackley; D. Steeghs; B. P. Gompertz; M. Magee; J. Lyman; R. Starling; M. J. Dyer; K. Ulaczyk; F. Jimenez-Ibarra; A. Kumar; D. O'Neill; D. K. Galloway; V. Dhillon; P. O'Brien; G. Ramsay; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration and the GOTO-FAST program:

We report on the classification of AT2024cew/GOTO24pw as part of the GOTO-FAST program (Godson et al., https://www.wis-tns.org/astronotes/astronote/2023-224). The source was first reported by GOTO (Belkin et al, GCN 35715) as a possible optical counterpart to GRB 240209A (Fermi GBM team, GCN 35712). It showed an initial decline across the GOTO epochs which was consistent with the ZTF photometry obtained through the Lasair broker (Smith et al. 2019).

Following the reported brightening of the source (de Ugarte Postigo et al., GCN 35716) we obtained spectroscopic observations on the night of 2024-02-13 with the Isaac Newton Telescope (INT) using the IDS spectrograph with R150V grating (3950-7900 A, R~600). The INT spectrum is consistent with a Type Ia-pec SN at a redshift of z=0.15 (Godson et al. 2024, https://www.wis-tns.org/astronotes/astronote/2024-52). AT2024cew is therefore unrelated to GRB 240209A. 

At this distance, the ongoing brightening measured by NOT (de Ugarte Postigo et al., GCN 35716), Wendelstein (Busmann et al., GCN 35724), and OHP (Turpin et al., GCN 35725) implies an absolute magnitude of -19.5. This is luminous for normal type Ia SNe and is consistent with peculiar SN Ia classification.

Based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de AstrofÃ­sica de Canarias.


GRB_name: GRB240215A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35733
SUBJECT: GRB 240215A: Swift/BAT-GUANO localization of a burst
DATE:    24/02/15 21:38:30 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Aaron Tohuvavohu (U Toronto), Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC)  report:

Swift/BAT did not localize GRB 240215A onboard (T0: 2024-02-15T15:33:00.41 UTC, Fermi/GBM trigger 729703985).

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.

In ground analysis of the available TTE data, we find the position of
the burst with SNR 13.9 in the image domain.

At the time of the trigger, Swift did not have a lock on its star tracker so positions may be inaccurate by up to a few tenths of a degree. 

The BAT position is
RA, Dec = 132.237, -6.4058, which is:
    RA (J2000)     08h 48m 56.88s
    Dec (J2000)  -06d 24' 20.88"
with an estimated statistical uncertainty of 3 arcminutes plus ~15 arcminutes due to loss of star tracker loss

XRT and UVOT follow-up has been requested.
Results of follow-up observations will be reported in future circulars.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240215A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35734
SUBJECT: GRB 240215A: Tiled Swift observations
DATE:    24/02/16 03:52:48 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>


P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
Swift/BAT GRB 240215A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00123

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the Swift/BAT event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240216A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35738
SUBJECT: Fermi GRB 240216A: Global MASTER-Net observations report
DATE:    24/02/16 18:31:24 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240216A ( Fermi GBM team, GCN 35736) errorbox  26194 sec after notice time and 26232 sec after trigger time at 2024-02-16 18:14:15 UT, with upper limit up to  17.9 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -10.0 deg. 

The galactic latitude b = -39 deg., longitude l = 293 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2379851

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   26262 | 2024-02-16 18:14:15 |         MASTER-SAAO | (01h 54m 51.71s , -76d 40m 43.0s) |   C |    60 | 17.9 |        
   26262 | 2024-02-16 18:14:15 |         MASTER-SAAO | (02h 32m 14.86s , -76d 51m 24.5s) |   C |    60 | 17.1 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240215B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35739
SUBJECT: GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV 
DATE:    24/02/16 18:36:56 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Samuele Ronchini (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: 

Swift/BAT did not localize GRB 240215B onboard (T0: 2024-02-15T19:51:43.85 UTC, Fermi trig 729719508) 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. 

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 28.8 in a 8.192 s analysis time bin, starting at T0. 

NITRATES results are consistent with a burst coming from outside the FOV, with DeltaLLHOut of -28.4.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. 

GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. 

A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240218A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35742
SUBJECT: GRB 240218A: Swift detection of a burst
DATE:    24/02/18 02:17:56 GMT
FROM:    K.L. Page at U Leicester <klp5@leicester.ac.uk>


K. L. Page (U Leicester), T. M. Parsotan (GSFC) and M. H. Siegel (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 02:00:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240218A (trigger=1215912).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 161.781, +1.304 which is 
   RA(J2000) = 10h 47m 07s
   Dec(J2000) = +01d 18' 14"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a broad single peak
structure after a period of noise with a duration of about 15 sec.  
The peak count rate was ~1400 counts/sec (15-350 keV), at ~22 sec after the trigger. 

The XRT began observing the field at 02:02:30.1 UT, 149.4 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 161.7953, 1.2782 which is equivalent to:
   RA(J2000)  = 10h 47m 10.87s
   Dec(J2000) = +01d 16' 41.5"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
location is 106 arcseconds from the BAT onboard position, within the
BAT error circle. No event data are yet available to determine the
column density using X-ray spectroscopy. 

UVOT took a finding chart exposure of 119 seconds with the White
filter  starting 158 seconds after the BAT trigger. No credible
afterglow candidate has  been found in the initial data products. The
2.7'x2.7' sub-image covers 100% of  the XRT error circle. The typical
3-sigma upper limit has been about 19.6 mag.   The 8'x8' region for
the list of sources generated on-board covers 100% of the  XRT error
circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to
E(B-V) of 0.045. 

Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240218A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35743
SUBJECT: GRB240218A: VLT/X-shooter upper limits
DATE:    24/02/18 03:49:19 GMT
FROM:    Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>

D. B Malesani (DAWN/NBI and Radboud Univ.) and E. Le Floch (CEA) report on behalf of the Stargate collaboration:

We observed the field of GRB 240218A (Page et al., GCN 35742) using the ESO VLT UT3 with the X-shooter acquisition camera. A short sequence of imaging was secured in the r, g, and z bands. No afterglow is detected consistent with the position reported by XRT (https://www.swift.ac.uk/xrt_positions/), with the following upper limits:

r band: r > 23.0 (AB) on Feb 18.124 UT (1.00 hr after the GRB);
z band: z > 21.5 (AB) on Feb 18.127 UT (1.07 hr after the GRB).

We acknowledge excellent support from the VLT staff in Paranal, in particular Jonathan Smoker, Thomas Szeifert, and Rodrigo Romero.


GRB_name: GRB240218A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35744
SUBJECT: GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
DATE:    24/02/18 05:10:36 GMT
FROM:    Emeric Le Floc'h at CEA-Saclay <emeric.lefloch@cea.fr>

C. Adami (LAM) and E. Le Floc'h (CEA-Saclay) report on behalf of the MISTRAL GRB collaboration:

We observed the field of GRB 240218A (Page et al., GCN 35742) using the MISTRAL spectro-imager mounted on the T193 telescope at Observatoire de Haute-Provence (France). We obtained a sequence of 5 images (5min, 10min, 3x15min) for an observation mid-time corresponding to 67min after the GRB) and a total observing time of 1h. Similar to the non detection reported earlier by Malesani et al. (GCN 35743), we did not detect any afterglow candidate consistent with the XRT position, down to the following upper limit :

r > 23 (AB)

The photometry was calibrated against the PanStarrs catalog within a circle of 2â€™ (radius) around the GRB position.

 We acknowledge excellent support from Observatoire de Haute Provence, in particular Yoann Degot Longhi.


GRB_name: GRB240213A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35745
SUBJECT: GRB 240213A: GRBAlpha detection
DATE:    24/02/18 08:52:14 GMT
FROM:    Marianna DafÄÃ­kovÃ¡ at Masaryk University <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240213A (Fermi/GBM detection: GCN 35718; Glowbug detection: GCN 35728; INTEGRAL/SPI-ACS peak detection at 2024-02-13 ~20:11:35) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-02-13 20:11:48 UTC. The T90 duration measured by GRBAlpha is 44.5 s and the overall significance during T90 reaches 28 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240213A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ 
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240218A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35748
SUBJECT: GRB 240218A: Enhanced Swift-XRT position
DATE:    24/02/18 12:09:38 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 75 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 240218A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 161.79682, +1.27634 which is equivalent
to:

RA (J2000): 10h 47m 11.24s
Dec (J2000): +01d 16' 34.8"

with an uncertainty of 4.2 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB240218A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35749
SUBJECT: GRB 240218A: VLT/FORS2 z-band detection
DATE:    24/02/18 15:18:26 GMT
FROM:    Daniele B. Malesani at IMAPP / Radboud University <d.malesani@astro.ru.nl>

We observed the near-infrared counterpart of GRB 240218A (Page et al., GCN 35742; D'Avanzo et al., GCN 35747) using the ESO VLT UT1 (Kueyen) equipped with the FORS2 imager. Observations were carried out in the Gunn z filter.

The GRB counterpart discovered by REM (D'Avanzo et al., GCN 35747) is well detected in the coaddition of our images (1080 s exposure time), at a mean epoch Feb 18.205 UT (2.925 hr after the GRB). Calibrated against nearby stars from the Pan-STARRS catalog, we preliminarily measure a magnitude z = 23.8 +- 0.15 (AB).

We acknowledge expert support from the VLT observing staff in Paranal, in particular Thomas Szeifert, Jonathan Smoker, Martina Baratella, and Juan Carlos Olivares.


GRB_name: GRB240209A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35751
SUBJECT: IPN triangulation of GRB 240209A
DATE:    24/02/18 17:22:41 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks,  A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

and

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

report:

The long-duration GRB 240209A
(Fermi-GBM detection: The Fermi GBM team, GCN 35712;
Malacaria et al., GCN 35729)
was detected by Fermi (GBM trigger 729152364) and
Konus-Wind, in the waiting mode, at about 22760 s UT (06:19:20).

We have triangulated it to a Konus-GBM annulus centered at
RA(2000)=119.672 deg (07h 58m 41s) Dec(2000)=+19.090 deg (+19d 05' 25"),
whose radius is 66.074 +/- 14.729 deg (3 sigma).

The annulus combined with the Fermi-GBM final position (GCN 35712;
glg_healpix_all_bn240209263_v01) gives ~2019 sq. deg (3 sigma) localization region.

The reported optical counterpart candidate GOTO24pw/AT2024cew
(Belkin et al., GCN 35715) is outside the Konus-GBM annulus,
implying that the optical transient is unrelated to the GRB.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB240209_T22759/IPN


GRB_name: GRB240215B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35752
SUBJECT: GRB 240215B: GRBAlpha detection
DATE:    24/02/18 21:35:25 GMT
FROM:    Andras Pal at Konkoly Observatory <apal@szofi.net>

A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240215B (Swift/BAT detection: GCN 35739; Fermi/GBM detection: GCN 35740; INTEGRAL/SPI-ACS peak detection at 2024-02-15 ~19:51:47) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; arXiv:2302.10048).

The detection was confirmed at the peak time 2024-02-15 19:51:49 UTC. The T90 duration measured by GRBAlpha is 16.5 s and the overall significance during T90 reaches 23 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240215B_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240216A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35753
SUBJECT: GRB 240216A: GRBAlpha detection
DATE:    24/02/18 21:45:38 GMT
FROM:    Andras Pal at Konkoly Observatory <apal@szofi.net>

A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The short-duration GRB 240216A (Fermi/GBM detection: GCN 35736; Konus/Wind trigger detection at 2024-02-16 10:57:01.022 UT; INTEGRAL/SPI-ACS peak detection at 2024-02-16 ~10:57:04 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).

The detection was confirmed at the peak time 2024-02-16 10:57:03 UTC. The T90 duration measured by GRBAlpha is 1.0 s and the overall significance during T90 reaches 8.8 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240216A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240215A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35754
SUBJECT: GRB 240215A: Fermi GBM Observation
DATE:    24/02/18 23:32:17 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

L. Scotton (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 15:33:00.41 UT on 15 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240215A (trigger 729703985/240215648),
which was also detected by Swift/BAT-GUANO (J. DeLaunay et al. 2024, GCN 35733).
The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.

The angle from the Fermi LAT boresight is 67 degrees.

The GBM light curve consists of a pulse followed by weak emission with a duration (T90)
of about 57 s (50-300 keV). The time-averaged spectrum
from T0-4.1 to T0+60.4 s is best fit by
a simple power law function with index -1.77 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(3.6 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band is 1.9 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240218A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35755
SUBJECT: GRB 240218A: Fermi GBM Detection
DATE:    24/02/19 01:21:14 GMT
FROM:    Peter Veres at University of Alabama in Huntsville <veresp@gmail.com>

P. Veres and C. Meegan (both UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 02:00:21.72 UT on 18 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240218A (trigger 729914426/240218084),
which was also detected by Swift/BAT (Page et al. 2024, GCN 35742). 
The Fermi GBM on-ground localization is consistent with the Swift BAT position.


The angle from the Fermi LAT boresight is 93 degrees.

The GBM light curve consists of a single pulse followed by weaker emission with a duration (T90)
of about 38 s (50-300 keV). The time-averaged spectrum
from T0-2.6 to T0+30.2 s is best fit by
a Band function with Epeak = 100 +/- 20 keV,
alpha = -0.3 +/- 0.3, and beta = -1.9 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(5.2 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.5 s in the 10-1000 keV band is 3.1 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240218A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35757
SUBJECT: GRB 240218A: Swift-XRT refined Analysis
DATE:    24/02/19 23:02:31 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M. Ferro
(INAF-OAB), R. Brivio (INAF-OAB), A. D'Ai (INAF-IASFPA), J. D. Gropp
(PSU), S. Dichiara (PSU), J.A. Kennea (PSU) and P.A. Evans report on
behalf of the Swift-XRT team:

We have analysed 5.7 ks of XRT data for GRB 240218A, from 137 s to
149.4 ks after the  BAT trigger. The data comprise 118 s in Windowed
Timing (WT) mode (the first 10 s were taken while Swift was slewing)
with the remainder in Photon Counting (PC) mode. 

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.12 (+0.11, -0.05), followed by a break at T+1538 s to
an alpha of 0.70 (+0.06, -0.05).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.39 (+/-0.04). The
best-fitting absorption column is  1.39 (+0.29, -0.27) x 10^23 cm^-2,
at a redshift of 6.782, in addition to the Galactic value of 4.2 x
10^20 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.8 x 10^-11 (5.3 x 10^-11) erg cm^-2 count^-1. 

A summary of the WT-mode spectrum is thus:
Galactic foreground: 4.2 x 10^20 cm^-2
Intrinsic column:    1.39 (+0.29, -0.27) x 10^23 cm^-2 at z=6.782
Photon index:      1.39 (+/-0.04)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01215912.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240218A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35758
SUBJECT: Konus-Wind detection of GRB 240218A
DATE:    24/02/20 02:33:53 GMT
FROM:    Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, A.Lysenko, A. Ridnaia,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long-duration GRB 240218A
(Swift-BAT detection: Page et al., GCN 35742;
Fermi-GBM detection: Veres and Meegan, GCN 35755)
was detected by Konus-Wind (KW) in the waiting mode.

A Bayesian block analysis of the KW waiting mode data
in the 20-400 keV band reveals a >10 sigma count rate increase
in the interval from T0-12.646 s to T0+25.626 s,
where T0 = T0(BAT) = 02:00:00 UT.
The burst light curve shows a multi-peaked structure
with the brightest peak around ~T0(BAT)+20 s.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240218_T07200/

As observed by Konus-Wind, the burst had
a total fluence of 7.62(-2.22,+1.72)x10^-6 erg/cm^2 and
a 2.944-s peak energy flux, measured from T0+19.738 s,
of 5.29(-1.49,+2.21)x10^-7 erg/cm^2/s
(both in the 20 keV - 10 MeV energy range).

Modelling the 3-channel time-integrated spectrum of the burst
(measured from T0-12.646 s to T0+25.626 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha > -0.56 and Ep = 180(-74,+77) keV.

Modelling the 3-channel spectrum near the peak count rate
(measured from T0+19.738 to T0+25.626 s) by the CPL model
yields alpha = -1.33(-0.29,+0.53) and Ep = 293(-120,+207) keV.

Assuming the redshift z=6.782 (Saccardi et al., GCN 35756)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),we estimate
the burst isotropic energy release E_iso to 5.4(-1.6,+1.2)x10^53 erg,
the isotropic peak luminosity L_iso to 2.9(-0.8,+1.2)x10^53 erg/s,
the rest-frame peak energy of the time-integrated spectrum
Ep,i,z to 1401(-576,+599) keV, and the rest-frame peak energy at
the peak of the emission Ep,p,z to 2280(-934,+1611) keV.

With the obtained estimates, GRB 240218A is inside 68% prediction band
for both 'Amati' and 'Yonetoku' relations derived for the sample of
>300 long KW GRBs with known redshifts (Tsvetkova et al., 2017;
Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB240218_T07200/GRB240218A_rest_frame.pdf

All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.


GRB_name: GRB240220A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35760
SUBJECT: Fermi GRB 240220A: Global MASTER-Net observations report
DATE:    24/02/20 11:30:34 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 240220A ( Fermi GBM team, GCN 35759) errorbox  308 sec after notice time and 342 sec after trigger time at 2024-02-20 11:21:06 UT, with upper limit up to  17.5 mag. The observations began at zenith distance = 37 deg. The sun  altitude  is -24.0 deg. 

The galactic latitude b = -22 deg., longitude l = 164 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2382619

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     372 | 2024-02-20 11:21:06 |         MASTER-Amur | (03h 32m 28.27s , +23d 57m 23.1s) |   C |    60 | 17.4 |        
     452 | 2024-02-20 11:22:25 |         MASTER-Amur | (03h 41m 17.33s , +23d 56m 30.1s) |   C |    60 | 17.5 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240218A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35761
SUBJECT: GRB 240218A: Swift-BAT refined analysis
DATE:    24/02/20 16:00:46 GMT
FROM:    Tyler Parsotan  at NASA GSFC <tyler.parsotan@nasa.gov>

S. D. Barthelmy (GSFC),  H. A. Krimm (NSF),

S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),

C. B. Markwardt (GSFC), M. J. Moss (GSFC),

D. M. Palmer (LANL), T. Parsotan (GSFC),

T. Sakamoto (AGU), (i.e. the Swift-BAT team):



Using the data set from T-240 to T+200 sec from the recent telemetry downlink,

we report further analysis of BAT GRB 240218A (trigger #1215912)

(Page, et al., GCN Circ. 35742).  The BAT ground-calculated position is

RA, Dec = 161.810, 1.295 deg which is

   RA(J2000)  =  10h 47m 14.4s

   Dec(J2000) = +01d 17' 40.2"

with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 36%.



The mask weighted light curve shows two major pulses, one that is broad and the other

which is narrow.

T90 (15-350 keV) is 66.93 +- 11.28 sec (estimated error including systematics).



The time-averaged spectrum from T-38.93 to T+63.55 sec is best fit by a power law

with an exponential cutoff.  This fit gives a photon index 1.00 +- 0.32,

and Epeak of 103.1 +- 45.5 keV (chi squared 62.59 for 56 d.o.f.).  For this

model the total fluence in the 15-150 keV band is 5.2 +- 0.3 x 10^-06 erg/cm2

and the 1-sec peak flux measured from T+21.62 sec in the 15-150 keV band is

3.0 +- 0.3 ph/cm2/sec.  A fit to a simple power law gives a photon index

of 1.51 +- 0.07 (chi squared 71.30 for 57 d.o.f.).  All the quoted errors

are at the 90% confidence level.



The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1215912/


GRB_name: GRB240218A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35762
SUBJECT: GRB 240218A: LBT H-band detection
DATE:    24/02/20 16:04:34 GMT
FROM:    Elisabetta Maiorano at INAF <elisabetta.maiorano@inaf.it>

A. Rossi, E. Maiorano, G. Stratta (INAF-OAS), P. D'Avanzo (INAF-OAB) report on behalf of the CIBO collaboration:

We observed the field of the long GRB 240218A, detected by Swift-BAT (Page et al., GCN 35742), Fermi-GBM (Veres and Meegan, GCN 35755) and Konus-Wind (Svinkin et al., GCN 35758), and with spectroscopic redshift of z=6.782 (Saccardi et al., GCN 35756).

We obtained 40 min of J-, 1 hr of H- and 1.2 hr of Ks-band imaging with the LUCI cameras mounted on LBT (Mt. Graham, AZ, USA) on 2024-02-19 (mid-time 08:20:00 UT), 1.3 days after the burst trigger. 

We clearly detect the NIR afterglow (D'Avanzo et al., GCN 35747, Malesani et al., GCN 35749) and measure a preliminary H-band magnitude of H ~ 20.2 AB, calibrated against 2MASS field stars, and not corrected for the foreground Galactic extinction.

We acknowledge the excellent support of A. Cardwell e J. Williams from the LBTO staff and E. Marini from LBT-INAF staff, in obtaining these observations.


GRB_name: GRB240215B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35763
SUBJECT: GRB 240215B: Fermi GBM Observation
DATE:    24/02/20 16:45:45 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

L. Scotton (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 19:51:43.85 UT on 15 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240215B (trigger 729719508/240215828),
which was also detected by Swift/BAT-GUANO (J. DeLaunay et al. 2024, GCN 35739), 
and GRBAlpha (A. Pal et al. 2024, GCN 35752).
The Fermi GBM Final Real-time Localization was reported in GCN 35740, 
but was mislabelled as GRB 240215C.
After manual inspection, a more accurate on-ground location was found to be 
RA = 309.52, Dec = -48.74, with a statistical uncertainty of 2.54 degrees.

The angle from the Fermi LAT boresight is 94 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 21 s (50-300 keV). The time-averaged spectrum
from T0-5.5 to T0+21.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.16 +/- 0.04 and the cutoff energy,
parameterized as Epeak, is 210 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval is
(1.12 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.9 s in the 10-1000 keV band is 10.8 +/- 0.4 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 190 +/- 20 keV, alpha = -1.13 +/- 0.05 and beta = -2.5 +/- 0.3.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240216A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35764
SUBJECT: GRB 240216A: Glowbug gamma-ray detection
DATE:    24/02/20 17:23:14 GMT
FROM:    C.C. Cheung at Naval Research Lab <Teddy.Cheung@nrl.navy.mil>

C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report:

The Glowbug gamma-ray telescope [1,2], operating on the International Space Station, reports the detection of GRB 240216A, which was also detected by Fermi/GBM (GCN 35736), GRBAlpha (GCN 35753), Konus/Wind (Trigger Time 10:57:01.022), and INTEGRAL/SPI-ACS (Trigger 10579).

Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2024-02-16 10:57:01.696 with a duration of 1.02 s and a total significance of about 15.4 sigma.  The light curve comprises a single peak.

Using a standard power-law function with an exponential high-energy cutoff [3] to model the emission over this duration results in a photon index dN/dE~E^x of x=0.3 and a cutoff energy ("Epeak") of 1230 keV.  The modeled 10-10000 keV fluence is 1.1e-06 erg/cm^2.

The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS.

Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC.  It was launched on 2023 March 15 aboard the Department of Defense Space Test Programâ€™s STP-H9 to the ISS.  The detector comprises 12 large-area (15 cm x 15 cm) CsI:Tl panels covering the surface of a half cube, and two hexagonal (5-cm diameter, 10-cm length) CLLB scintillators, giving it a large field of view (instantaneous FoV ~2/3 sky) over a wide energy band of 50 keV to >2 MeV.

[1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959
[2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O
[3] Goldstein, A. et al. 2020, ApJ 895, 40, arXiv :1909.03006

Distribution Statement A: Approved for public release.  Distribution is unlimited.


GRB_name: GRB240218A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35765
SUBJECT: GRB 240218A: MeerLICHT upper limits
DATE:    24/02/20 20:32:37 GMT
FROM:    Simon de Wet at University of Cape Town <simdewet@gmail.com>

S. de Wet (UCT), P.M. Vreeswijk (Radboud) and P.J. Groot (Radboud/UCT/SAAO) report on behalf of the MeerLICHT consortium:

The 0.6m wide-field MeerLICHT optical telescope located in Sutherland, South Africa, obtained a repeating series of 60s exposures in the q,u,g,r,i,z filters following the detection of GRB 240218A by Swift (Page et al., GCN 35742). Our observations began 96 seconds after the Swift trigger and continued for approximately 1 hour following the filter sequence quqgqrqiqz.

We do not detect an optical source at a position consistent with the high-redshift counterpart detected by REM and the VLT (D'Avanzo et al., GCN 35747; Malesani, GCN 35749; Saccardi et al., GCN 35756) in any individual exposure. Our earliest 3-sigma AB limiting magnitudes in each filter are:

u > 19.29 at 3.6 minutes post-trigger
g > 20.58 at 6.5 minutes post-trigger
q > 21.10 at 2.1 minutes post-trigger
r > 20.29 at 9.4 minutes post-trigger
i > 19.81 at 13.4 minutes post-trigger
z > 18.87 at 15.3 minutes post-trigger.

We additionally co-added all of the images in each filter and obtain the following 3-sigma AB limiting magnitudes at an average time of 36 minutes post-trigger: 

u > 20.33 
g > 21.61 
q > 22.67
r > 21.21
i > 20.54
z > 19.54.
 
MeerLICHT is built and run by a consortium consisting of Radboud University, University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam. 


GRB_name: GRB240222A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35769
SUBJECT: GRB 240222A: Fermi GBM Final Real-time Localization
DATE:    24/02/22 09:02:21 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 08:51:31 UT on 22 Feb 2024, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 240222A (trigger 730284696.466782 / 240222369).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 143.3, Dec = -60.4 (J2000 degrees, equivalent to J2000 09h 33m, -60d 23'), with a statistical uncertainty of 9.1 degrees.

The angle from the Fermi LAT boresight is 109.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240222369/quicklook/glg_skymap_all_bn240222369.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240222369/quicklook/glg_healpix_all_bn240222369.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2024/bn240222369/quicklook/glg_lc_medres34_bn240222369.gif


GRB_name: GRB240222A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35770
SUBJECT: GRB 240222A: Swift detection of a burst
DATE:    24/02/22 09:04:46 GMT
FROM:    Paolo D'Avanzo at INAF - OAB <paolo.davanzo@inaf.it>


P. D'Avanzo (INAF-OAB), R. Brivio (INAF-OAB), S. Dichiara (PSU),
A. Y. Lien (U Tampa), K. L. Page (U Leicester),
C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB) and
B. Sbarufatti (INAF-OAB) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 08:51:31 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 240222A (trigger=1216804).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 143.248, -68.029 which is 
   RA(J2000) = 09h 32m 59s
   Dec(J2000) = -68d 01' 43"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 20 sec.  The peak count rate
was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 08:53:05.3 UT, 94.0 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 143.22556, -68.03102 which
is equivalent to:
   RA(J2000)  = 09h 32m 54.13s
   Dec(J2000) = -68d 01' 51.7"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 31 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.72 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 4.6
(+3.44/-2.96) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 98 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.166. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT inaf.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB240222A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35774
SUBJECT: Fermi GRB 240222A: Global MASTER-Net observations report
DATE:    24/02/22 18:31:17 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 240222A ( Fermi GBM team, GCN 35769) errorbox  33348 sec after notice time and 33382 sec after trigger time at 2024-02-22 18:07:54 UT, with upper limit up to  18.3 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -10.1 deg. 

The galactic latitude b = -6 deg., longitude l = 281 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2383850

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   33473 | 2024-02-22 18:07:54 |         MASTER-SAAO | (09h 40m 49.96s , -68d 03m 28.5s) |   C |   180 | 17.9 |        
   33473 | 2024-02-22 18:07:54 |         MASTER-SAAO | (09h 18m 15.91s , -67d 52m 27.6s) |   C |   180 | 17.4 |        
   33672 | 2024-02-22 18:11:13 |         MASTER-SAAO | (09h 40m 56.74s , -68d 04m 32.3s) |   C |   180 | 18.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240222A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35775
SUBJECT: Swift GRB 240222A: Global MASTER-Net observations report
DATE:    24/02/22 18:32:47 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E. Gorbovskoy, K. Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.Senik,  D. Vlasenko,
G.Antipov, D.Zimnukhov, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D. Cheryasov, Ya.Kechin, Yu.Tselik, A. Sosnovskij
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra
(The Instituto de Astrofisica de Canarias),

D. Buckley
(South African Astronomical Observatory),

O.A. Gress, N.M. Budnev, O.Ershova
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov
(Kislovodsk Solar Station of the Pulkovo Observatory),

V. Yurkov, A. Gabovich
(Blagoveschensk Educational State University)

MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 240222A ( P. D'Avanzo et al., GCN 35770) errorbox  33361 sec after notice time and 33382 sec after trigger time at 2024-02-22 18:07:54 UT, with upper limit up to  18.3 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -10.1 deg. 

The galactic latitude b = -12 deg., longitude l = 286 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2383830

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   33473 |         MASTER-SAAO |   C |   180 | 17.9 |        
   33473 |         MASTER-SAAO |   C |   180 | 17.4 |        
   33672 |         MASTER-SAAO |   C |   180 | 18.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB240222A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35777
SUBJECT: GRB 240222A: Swift/UVOT Upper Limits
DATE:    24/02/22 22:34:59 GMT
FROM:    Samantha Oates at University of Birmingham <samantha.oates@alumni.ucl.ac.uk>

S. R. Oates (Lancaster. U) and P. D'Avanzo (INAF-OAB) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240222A
98s after the BAT trigger (D'Avanzo et al., GCN Circ 35770). No optical
afterglow consistent with X-ray (D'Avanzo et al., GCN Circ. 35770) position is
detected in the initial UVOT exposures.

Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white          98            1192          205            >20.9
v              642           1068           58            >18.5
b              567           1168           58            >19.5
u              311           1142          285            >20.0
uvw1           691           1118           39            >18.3
uvm2           666           861            39            >18.0
uvw2           617           1044           58            >18.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.16 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB240222A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35778
SUBJECT: GRB 240222A: Fermi GBM Observation
DATE:    24/02/22 23:39:37 GMT
FROM:    Joe Mangan at IJCLab <joseph.mangan@ijclab.in2p3.fr>

J. Mangan (CNRS/IJCLab) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 08:51:31.47 UT on 22 February 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 240222A (trigger 730284696/240222369).
which was also detected by Swift BAT (P. D'Avanzo et al. 2024, GCN 35770).
The Fermi GBM on-ground location is consistent with the Swift BAT position.

The angle from the Fermi LAT boresight is 109 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 3.8 s (50-300 keV). The time-averaged spectrum
from T0-5.9 to T0+3.3 s is best fit by
a simple power law function with index -1.4 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(9.2 +/- 1.9)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.19 s in the 10-1000 keV band is 4 +/- 0.7 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB240222A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35780
SUBJECT: GRB 240222A: Swift-XRT refined Analysis
DATE:    24/02/23 01:05:15 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>

A.P. Beardmore (U. Leicester), R. Brivio (INAF-OAB), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAR), S. Dichiara (PSU), J.A. Kennea
(PSU), A. Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester) and P.A.
Evans report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 240222A, from 106 s to 41.2
ks after the  BAT trigger. The data comprise 9 s in Windowed Timing
(WT) mode (taken while Swift was slewing), with the remainder in Photon
Counting (PC) mode. The refined XRT position is RA, Dec = 143.2254,
-68.0305 which is equivalent to:

RA (J2000): 09 32 54.10
Dec(J2000): -68 01 49.7

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.02 (+0.12, -0.11).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.52 (+0.24, -0.12). The
best-fitting absorption column is  consistent with the Galactic value
of 1.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.6 x 10^-11 (5.3 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.7 (+/-0.9) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.52 (+0.24, -0.12)

If the light curve continues to decay with a power-law decay index of
2.02, the count rate at T+24 hours will be 1.3 x 10^-5 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.8 x
10^-16 (6.7 x 10^-16) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01216804.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB240222A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35781
SUBJECT: GRB 240222A: Swift-BAT refined analysis
DATE:    24/02/23 03:51:30 GMT
FROM:    Amy <yarleen@gmail.com>

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
P. D'Avanzo (INAF-OAB), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
M. J. Moss (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC), T. Sakamoto (AGU)
(i.e. the Swift-BAT team):

Using the data set from T-60 to T+243 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 240222A (trigger #1216804)
(D'Avanzo et al., GCN Circ. 35770).  The BAT ground-calculated position is
RA, Dec = 143.209, -68.034 deg which is
   RA(J2000)  =  09h 32m 50.2s
   Dec(J2000) = -68d 02' 03.7"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 94%.

The mask-weighted light curve shows a main pulse that starts
at ~T-0.4 s, peaks at ~T0, and ends at ~T+1.4 s. In addition,
there is a small precursor pulse at ~T-2.7 s. T90 (15-350 keV)
is 3.94 +- 2.35 sec (estimated error including systematics).

The time-averaged spectrum from T-2.70 to T+1.37 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 0.75 +- 0.23.  The fluence in the 15-150 keV band
is 2.5 +- 0.3 x 10^-7 erg/cm2. The 1-sec peak photon flux measured
from T-0.20 sec in the 15-150 keV band is 1.3 +- 0.2 ph/cm2/sec.
All the quoted errors are at the 90% confidence level.

The results of the batgrbproduct analysis are available at
https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1216804/


GRB_name: GRB240222A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35782
SUBJECT: GRB 240222A: GECAM detection of a burst
DATE:    24/02/23 06:22:36 GMT
FROM:    wenlongzhang2018@163.com

Sheng-Lun Xie, Shao-Lin Xiong, Wen-Long Zhang report on behalf of the GECAM team:

GECAM-B was triggered in-flight and on-ground by a short burst, GRB 240222A, at 2024-02-22T08:51:31.500 UTC (T0), which was also observed by Fermi/GBM (GCN #35769 and GCN #35778) and Swift/BAT (GCN #35770 and GCN #35781). 

According to the GECAM-B light curve, this burst consists of roughly a pulse with a total duration of ~3 sec. 

The GECAM-B ground calculated location (J2000) is:
Ra: 169.76 deg   
Dec: -71.58 deg
Err: 14.01 deg (1-sigma, statistical only)
This GECAM-B localization is consistent with that of Swift/BAT within the error.

We note that these results are very preliminary. Refined analysis will be reported later.

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM) mission originally consists of two microsatellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).


GRB_name: GRB240222A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35792
SUBJECT: GRB 240222A: GRBAlpha detection
DATE:    24/02/25 20:00:12 GMT
FROM:    Andras Pal at Konkoly Observatory <apal@szofi.net>

A. Pal (Konkoly Observatory), M. Dafcikova, J. Ripa, M. Kolar, N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, L. Szakszonova, J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 240222A (Fermi/GBM detection: GCN 35769; Swift/BAT detection: GCN 35770; GECAM-B detection: GCN 35782; INTEGRAL/SPI-ACS peak detection at 2024-02-22 ~08:51:32 UT) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract).

The detection was confirmed at the peak time 2024-02-22 08:51:31 UTC. The T90 duration measured by GRBAlpha is 1.5 s and the overall significance during T90 reaches 6.3 sigma.

The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB240222A_GCN.pdf

All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/
GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. 


GRB_name: GRB240225A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35793
SUBJECT: GRB 240225A: Swift/BAT-GUANO detection of a short burst
DATE:    24/02/25 23:15:07 GMT
FROM:    Jimmy DeLaunay at Penn State <delauj2@gmail.com>

James DeLaunay (PSU), Gayathri Raman (PSU), Samuele Ronchini (PSU), Aaron Tohuvavohu (U Toronto), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report:

Swift/BAT did not localize GRB 240225A onboard (T0: 2024-02-25T04:20:16.59 UTC, INTEGRAL SPI-ACS trigger 10589). 

The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). 

Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground.

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), performed on the temporal window [T0-20 s, T0+20 s], detects the burst with a sqrt(TS) of 9.0 in a 1.024 s analysis time bin, starting at T0 + 1.28 s. 

NITRATES results, independently, are ambiguous with respect to whether this burst originates from in or outside the BAT coded FOV, with a DeltaLLHOut of 6.5.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB240218A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35794
SUBJECT: GRB 240218A: VLA detection
DATE:    24/02/26 01:13:49 GMT
FROM:    Genevieve Schroeder at Northwestern University <genevieveschroeder@u.northwestern.edu>

G. Schroeder (Northwestern), C. PeÃ±a, T. Laskar (Utah), K. D. Alexander (Arizona) report:

"We observed GRB 240218A (Page et al., GCN 35742;  Veres et al., GCN 35755; Svinkin et al., GCN 35758) with the Karl G. Jansky Very Large Array (VLA) under program 24A-299 (PI: Laskar) beginning on 2024 Feb 23 at 09:38:35 UT (5.32 days post-burst) for 2.5 hours at multiple frequencies.

In preliminary analysis, we clearly detect a radio source at a mean frequency of 9.8 GHz with a flux density of ~280 microJy at the position:

RA(J2000) = 10:47:11.480
Dec(J2000) = +01:16:35.29

with an uncertainty of ~0.2" in each coordinate. This position is consistent with the X-ray position (Evans et al. GCN 35748) but offset (~2.7") from the preliminary NIR afterglow position reported by D'Avanzo et al. (GCN 35747). Further observations are planned.

We thank the VLA staff for scheduling and executing these observations."


GRB_name: GRB240225B
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35796
SUBJECT: GRB 240225B: MAXI/GSC detection
DATE:    24/02/26 03:37:58 GMT
FROM:    Yuta Kawakubo at Louisiana State University <kawakubo1@lsu.edu>

M. Nakajima, H. Negoro (Nihon U.), Y. Kawakubo (LSU),
K. Kobayashi, M. Tanaka, Y. Soejima, Y. Kudo (Nihon U.),
T. Mihara, T. Kawamuro, S. Yamada, S. Wang, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN),
T. Sakamoto, M. Serino, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU),
Y. Tsuboi, S. Urabe, S. Nawa, N. Nemoto, E.Goto (Chuo U.),
M. Shidatsu (Ehime U.),
I. Takahashi, M. Niwano, S. Sato, N. Higuchi, Y. Yatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, S. Ogawa, T. Kurihara (JAXA),
Y. Ueda, K. Setoguchi, T. Yoshitake, Y. Nakatani, Y. Okada (Kyoto U.),
M. Yamauchi, Y. Hagiwara, Y. Umeki, Y. Otsuki (Miyazaki U.),
K. Yamaoka (Nagoya U.),
M. Sugizaki (NAOC),
W. Iwakiri (Chiba U.)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source  
at 20:15:46 UT on February 25, 2024.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (128.458 deg, 27.487 deg) = (08 33 49, +27 29 13) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.13 deg and 0.11 deg, respectively.
The roll angle of long axis from the north direction is 67.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 874 +- 86 mCrab
(4.0-10.0keV, 1 sigma error).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(R.A., Dec) = (127.906, 26.756) deg = (08 31 37, +26 45 21) (J2000)
(R.A., Dec) = (128.157, 26.654) deg = (08 32 37, +26 39 14) (J2000)
(R.A., Dec) = (128.895, 28.075) deg = (08 35 34, +28 04 29) (J2000)
(R.A., Dec) = (128.642, 28.179) deg = (08 34 34, +28 10 44) (J2000)
There was no significant excess flux in the previous transit at 18:43 UT
and in the next transit at 21:48 UT with an upper limit of 20 mCrab for each.


GRB_name: GRB240225B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  35797
SUBJECT: GRB 240225B: Tiled Swift observations
DATE:    24/02/26 04:13:59 GMT
FROM:    Phil Evans at U of Leicester <pae9@star.le.ac.uk>


P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
MAXI GRB 240225B. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00124

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the MAXI event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


