# GCN_circulars

GRB_name: GRB190311A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23946
SUBJECT: GRB 190311A: Swift detection of a burst with optical counterpart
DATE:    19/03/11 14:43:26 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

E. Troja (NASA/GSFC/UMCP), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU),
N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
M. J. Moss (George Washington University), K. L. Page (U Leicester)
and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 14:23:33 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190311A (trigger=892607).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 212.102, +53.519 which is 
   RA(J2000) = 14h 08m 24s
   Dec(J2000) = +53d 31' 10"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). From the available data, the BAT light curve showed 
a single-peaked structure with duration of at least 10 sec. However, due to 
a data gap from ~T+10 s to ~ T+ 110 s, there might be additional emission
in that time interval. The peak count rate was ~1700 counts/sec (15-350 keV), 
at ~ 0 sec after the trigger. 

The XRT began observing the field at 14:24:54.0 UT, 80.3 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
212.0649, 53.5007 which is equivalent to:
   RA(J2000)  = 14h 08m 15.58s
   Dec(J2000) = +53d 30' 02.7"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 103 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
http://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 (1.17 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 5.1
(+3.27/-2.92) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 5.45e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 85 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 14:08:15.65 = 212.06522
  DEC(J2000) = +53:30:03.0  =  53.50084
with a 90%-confidence error radius of about 0.60 arc sec. This position is 0.85
arc sec. from the center of the XRT error circle. The estimated magnitude is
19.47 with a 1-sigma error of about  0.12. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.01. 

Burst Advocate for this burst is E. Troja (eleonora.troja 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: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23947
SUBJECT: GRB 190311A: Mondy optical observations
DATE:    19/03/11 15:49:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Pozanenko (IKI), E. Mazaeva (IKI),  E. Klunko (ISTP), A. Volnova 
(IKI), S. Belkin (IKI)  report   on behalf of IKI-GRB-FuN:

We observed the field of  GRB 190311A  (Troja et al.  GCN 23946) with 
AZT-33IK telescope of Sayan observatory (Mondy) starting on Mar. 11 (UT) 
  14:39:17.   We  clearly  detected  the candidate in optical afterglow 
(Troja et al.  GCN 23946). Coordinates of the optical transient are 
(J2000) 14:08:15.74 +53:30:03.1 with uncertainty of 0.5 arcsec in both 
coordinates, which correspond to the coordinates obtained in GCN 23946. 
  Preliminary photometry of the afterglow in R-filter is following.

t-T0_mid(d) t-T0_mid(min) R_mag err
0.01111 16.0 19.22 0.11
0.01146 16.5 19.25 0.10
0.01180 17.0 19.50 0.11
0.01215 17.5 19.23 0.10
0.01250 18.0 19.47 0.12
0.01285 18.5 19.46 0.10
0.01348 19.4 19.50 0.08
0.01417 20.4 19.62 0.08
0.01487 21.4 19.55 0.09
0.01556 22.4 19.58 0.08
0.01626 23.4 19.56 0.09
0.01695 24.4 19.62 0.09
0.01765 25.4 19.79 0.10
0.01875 27.0 19.83 0.06
0.02014 29.0 19.83 0.06

Photometry is based on the SDSS-DR12 stars (Lupton transformations)
SDSS-DR12_id         R
J140819.68+532900.1 17.09
J140818.11+532934.7 15.19
J140809.64+533055.9 16.97
J140807.35+533116.9 16.11

The optical transient is fading and we can confirm the optical afterglow 
of  GRB 190311A.


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23948
SUBJECT: GRB 190311A: NEXT-0.6m optical afterglow detection
DATE:    19/03/11 15:50:36 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Z.P. Zhu, D. Xu, B.Y. Yu (NAOC) report on behalf of larger collaboration:

We observed the field of GRB 190311A (Troja et al., GCN 23946) using the 
robotic NEXT-0.6m telescope located at Nanshan, Xinjiang, China. 
Observations started at 14:25:14 UT on 2019-03-11, i.e., 101 sec after 
the BAT trigger. A series of 40 s, 60 s , 90 s, 300 s R-band frames were 
obtained, and photometry is still ongoing.

An uncatalogued optical source is detected at coordinates

R.A. (J2000) = 14:08:15.71
Dec. (J2000) = +53:30:01.7

with an uncertainty radius ~0.3 arcsec, being consistent with Swift/UVOT 
position  (Troja et al., GCN 23946). The source has m(R) ~ 19.7 mag at 
413 s post-burst, and is fading. We conclude that the source is the 
optical afterglow of the burst.


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23949
SUBJECT: GRB190311A: MASTER Global Robotic Net OT optical observation 
DATE:    19/03/11 16:18:57 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

E. Gorbovskoy, V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, 
D.Vlasenko, V.Vladimirov,  D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, D.Kuvshinov (Lomonosov Moscow State 
University, SAI, Physics Department),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova (Applied Physics Institute, 
Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational 
State University),

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto 
de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

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

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

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE)

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  GRB190311.6 (Troja et al., 
23946) 55 sec after notice time 
and 66 sec after trigger time at 2019-03-11 14:24:45 UT. On our third (30 
s  exposure)  set we  found optical transient  within SWIFT 
error-box at Swift UVOT position (Troja et al., 23946).

m ~ 17.5
RA, DEC = 14:08:15.72, +53:30:02.9
err = 1 arcsec

We obtain a following images with OT:

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

      109 |        MASTER-Tunka |  P- |    10 | 16.82 |
      109 |        MASTER-Tunka |  P- |    80 | 18.47 |  Coadd
      109 |        MASTER-Tunka |  P| |    10 | 16.69 |
      109 |        MASTER-Tunka |  P| |    80 | 18.33 |  Coadd
      231 |        MASTER-Tunka |  P| |    30 | 17.60 |
      231 |        MASTER-Tunka |  P- |    30 | 17.74 |
      338 |        MASTER-Tunka |  P| |    40 | 17.70 |
      338 |        MASTER-Tunka |  P- |    40 | 17.87 |
      462 |         MASTER-Amur |  P/ |    60 | 13.12 |
      465 |        MASTER-Tunka |  P| |    60 | 18.12 |
      465 |        MASTER-Tunka |  P| |   250 | 19.14 |  Coadd
      465 |        MASTER-Tunka |  P- |    60 | 18.21 |
      465 |        MASTER-Tunka |  P- |   250 | 19.24 |  Coadd
      593 |         MASTER-Amur |  P/ |    60 | 12.20 |
      614 |        MASTER-Tunka |  P| |    80 | 18.50 |
      614 |        MASTER-Tunka |  P- |    80 | 18.43 |
      808 |        MASTER-Tunka |  P| |   110 | 18.65 |
      808 |        MASTER-Tunka |  P- |   110 | 18.65 |
     1032 |        MASTER-Tunka |  P| |   140 | 18.56 |
     1032 |        MASTER-Tunka |  P| |   490 | 19.35 |  Coadd
     1032 |        MASTER-Tunka |  P- |   140 | 18.55 |
     1032 |        MASTER-Tunka |  P- |   490 | 19.30 |  Coadd
     1305 |        MASTER-Tunka |  P| |   170 | 18.64 |
     1305 |        MASTER-Tunka |  P- |   170 | 18.63 |
     1622 |        MASTER-Tunka |  P| |   180 | 19.02 |
     1623 |        MASTER-Tunka |  P- |   180 | 18.89 |
     1949 |        MASTER-Tunka |  P| |   180 | 17.67 |
     1949 |        MASTER-Tunka |  P| |   540 | 19.26 |  Coadd
     1949 |        MASTER-Tunka |  P- |   180 | 17.63 |
     1949 |        MASTER-Tunka |  P- |   540 | 19.22 |  Coadd
     2284 |        MASTER-Tunka |  P| |   180 | 18.90 |
     2284 |        MASTER-Tunka |  P- |   180 | 18.98 |
     2616 |        MASTER-Tunka |  P| |   180 | 19.01 |
     2949 |        MASTER-Tunka |  P| |   180 | 19.10 |
     2949 |        MASTER-Tunka |  P| |   540 | 19.83 |  Coadd
     2949 |        MASTER-Tunka |  P- |   540 | 19.72 |  Coadd
     3959 |        MASTER-Tunka |  P- |   540 | 19.60 |  Coadd
     3959 |        MASTER-Tunka |  P| |   540 | 19.87 |  Coadd
     5650 |        MASTER-Tunka |  P| |   180 | 19.20 |
     5650 |        MASTER-Tunka |  P- |   180 | 18.89 |
     5979 |        MASTER-Tunka |  P- |   180 | 18.74 |
     5979 |        MASTER-Tunka |  P| |   180 | 19.02 |
     6312 |        MASTER-Tunka |  P| |   180 | 18.66 |
     6312 |        MASTER-Tunka |  P- |   180 | 18.79 |


The 5-sigma upper limit has been about 16.32mag
The message may be cited.


====================================================================


The galactic latitude b = 60 deg., longitude l = 99 deg.
The observations made on zenit distance = 48 deg.The moon (22 % bright 
part) is 14 deg. above the horizon. The distance between  moon and  object 
is 113
The sun  altitude  is -30.2 deg.
The object can be observed till sunrise at 2019-03-12 23:26:58.


This message can be cited.


GRB_name: GRB190311A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23950
SUBJECT: GRB 190311A: Enhanced Swift-XRT position
DATE:    19/03/11 16:37:34 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1682 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 190311A, 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 = 212.06539, +53.50037 which is equivalent
to:

RA (J2000): 14h 08m 15.69s
Dec (J2000): +53d 30' 01.3"

with an uncertainty of 1.8 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: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23951
SUBJECT: GRB 190311A: TSHAO optical observations
DATE:    19/03/11 20:28:35 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), I. Reva (FAPHI), A. Pozanenko (IKI), E. Mazaeva (IKI), 
A. Volnova (IKI), A. Kusakin (FAPHI), M. Krugov (FAPHI)  report   on 
behalf of IKI-GRB-FuN:

We observed the afterglow of GRB 190311A (Troja et al.  GCN 23946) with 
Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory starting 
on Mar. 11 (UT) 15:54:08.   Preliminary photometry of the afterglow 
detected previously (Troja et al.  GCN 23946; Pozanenko et al.  GCN 
23947; Zhu et al.  GCN 23948; Gorbovskoy et al.  GCN 23949) is following.

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

2019-03-11 15:54:08 0.07228  R      3240 20.87 0.24  21.4

The photometry is based the stars used for calibration in GCN 23947.


GRB_name: GRB190311A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23952
SUBJECT: GRB 190311A: Swift-XRT refined Analysis
DATE:    19/03/12 01:18:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Tohuvavohu (PSU), S. J. LaPorte (PSU), K.L. Page (U. Leicester),
A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), V. D'Elia
(ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), J.A. Kennea
(PSU) and E. Troja report on behalf of the Swift-XRT team:

We have analysed 7.6 ks of XRT data for GRB 190311A (Troja et al. GCN
Circ. 23946), from 86 s to 19.1 ks after the  BAT trigger. The data
comprise 80 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Goad et al. (GCN Circ. 23950).

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.27 (+0.38, -0.19), followed by a break at T+386 s to
an alpha of 0.56 (+0.12, -0.08).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.79 (+0.25, -0.24). The
best-fitting absorption column is  2.1 (+1.2, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 1.2 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.04 (+0.19, -0.18)
and a best-fitting absorption column of 3.8 (+0.9, -0.8) 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 (5.9 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.8 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 1.2 x 10^20 cm^-2
Excess significance: 7.3 sigma
Photon index:      2.04 (+0.19, -0.18)

If the light curve continues to decay with a power-law decay index of
0.56, the count rate at T+24 hours will be 0.022 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.2 x
10^-13 (1.3 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00892607.

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


GRB_name: GRB190311A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23953
SUBJECT: GRB 190311A: Fermi GBM observation
DATE:    19/03/12 02:09:13 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 14:23:37.601 UT on 11 March 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190311A (trigger 574007022 / 190311600),
which was also detected by the Swift/BAT
(Troja et al., GCN 23946). The GBM on-ground location is consistent with
the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 128
degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 12.5 s (50-300 keV).
The time-averaged spectrum from T0-4.1 s to T0+3.1 s is
adequately fit by a simple power law function with index 1.86 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(1.40 +/- 0.18)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-2.75 s in the 10-1000 keV band
is 3.00 +/- 0.35 ph/s/cm^2.

A power law function with an exponential
high-energy cutoff fits the spectrum equally well
with Epeak= 89 +/- 34 keV and alpha = -1.51 +/- 0.25.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23954
SUBJECT: GRB 190311A: GMG observation
DATE:    19/03/12 05:10:29 GMT
FROM:    Jirong Mao at Yunnan Obs  <jirongmao_obs@ynao.ac.cn>

J. Mao, X.-L. Zhang, and J.-M. Bai (YNAO) report: 


We observed the field of GRB 190311A (Troja et al. GCN Circ. 23946) with the 2.4-meter optical telescope at Gao-Mei-Gu (GMG) station of Yunnan Observatories. The observation began at UT 16:15:07, 11, March, 2019, about 2 hours after the trigger. We clearly detected the afterglow (Pozanenko et al. GCN Circ. 23947; Zhu et al. GCN Circ 23948; Belkin et al. GCN Circ. 23951) , and the preliminary magnitude is measured to be R~20.6.


GRB_name: GRB190310A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23955
SUBJECT: [Hxmt-ba]GRB 190310A: Insight-HXMT/HE detection
DATE:    19/03/12 07:07:30 GMT
FROM:    Ce Cai at IHEP  <caice@ihep.ac.cn>

C. Cai, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2019-03-10T09:33:25.000 (T0), the Insight-HXMT/HE detected 
GRB 190310A (trigger ID: HEB190310398) in a routine search of the data, 
which was also triggered by Fermi/GBM (trigger number 573903157).
 
The Insight-HXMT/HE light curve mainly consists of Single 
pulse with a duration (T90) of 8.18 s measured from T0-1.74 s. 
The 1-ms peak rate, measured from T0+0.01 s, is 960 cnts/s. 
The total counts from this burst is 4615 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190310398_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy).
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23958
SUBJECT: GRB 190311A: Mondy optical observations
DATE:    19/03/12 14:34:41 GMT
FROM:    Elena Mazaeva at IKI, Moscow  <30.v@mail.ru>

E. Mazaeva (IKI), E. Klunko (ISTP), A. Pozanenko (IKI), S. Belkin (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN:

We continue to observe optical afterglow of GRB 190311A (Troja et al. GCN 23946; Pozanenko et al. GCN 23947; Zhu et al. GCN 23948; Gorbovskoy et al. GCN 23949; Belkin et al. GCN 23951; Mao et al. GCN 23954) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Mar. 11 (UT) 15:11:33 (31 minutes after GRB trigger).

Light curve of the afterglow in R-filter (of the full set of the observations incl. reported earlier in GCNs 23947, 23951) can be found at:
http://grb.rssi.ru/GRB190311A/GRB190311A_LC.png

Photometry is based on the SDSS-DR12 stars (Lupton transformations)
SDSS-DR12_id R
J140819.68 +532900.1 17.09
J140818.11 +532934.7 15.19
J140809.64 +533055.9 16.97


GRB_name: GRB190311A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23959
SUBJECT: GRB190311A: OAO observations
DATE:    19/03/12 15:13:24 GMT
FROM:    Alberto Fernandez-Soto at IFCA (CSIC/UC,Santander)  <fsoto@ifca.unican.es>

V. Peris (OAUV-Valencia) and A. Fernandez-Soto (IFCA-Santander) report:

We have observed the field of GRB190311A (Troja et al., GCN 23946) with
the OAUV-0.5m telescope at the Observatorio de Aras de los Olmos (OAO)
in Aras de los Olmos (Valencia, Spain). Observations began after local
midnight on March 12 (UT 01:03, (t-t0) ~ 10.7 hours ~ 0.444 days).

We took 23 ten-minute exposures using a Johnson R filter, out of which 
15 have been selected based on best quality. The afterglow reported in 
GCN23946 and confirmed by Pozanenko et al. (GCN 23947) is
clearly detected in our combined image, with the following magnitude 
and timestamp:

UT(middle)    (t-t0)  Exposure    R    Error
----------   -------  --------  -----  -----
  03:41:46   0.4443d  15x10min  21.45   0.15

The image has been calibrated using 100 stars in the field, the
APASS catalog (r and i mags) and the conversion equations in Lupton 
(2005) as given in the SDSS pages. The calibration zeropoint error is
not significant in comparison with the flux uncertainty (Delta(ZP)~0.03).

Our results confirm the fading of the afterglow and extend the time 
baseline from previous observations. We cannot at the present stage
measure the fading rate within our observations.

OAO is operated by the Observatori Astronomic de la Universitat de
Valencia (OAUV).


GRB_name: GRB190305A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23960
SUBJECT: GRB190305A: MASTER Global Robotic Net  optical observation 
DATE:    19/03/12 15:34:50 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov,  D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova, S.Yazev (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

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

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

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE)

MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v. 2010, 30L)
automatically pointed to MAXI GRB 190305A error box (00 45 17 dec=-50 07 18, r=1) (Nakahira et al. GCN 23933),
also detected by Ursi A. et al. GCN 23930,Xiao et al. GCN 23934, Svinkin et al. 23936, Kozlova et al. GCN 23939, Morita et al. GCN 23944
https://gcn.gsfc.nasa.gov/other/190305A.gcn3 ).

MASTER-SAAO (located in South African Astronomical Observatory)
automatically started GRB 190305A observations 7776 sec after notice time 
(18080 sec after trigger time) at 2019-03-05 18:09:03 UT
with unfiltered magnitude limit 19.6 (5 sigma).

Observations started when
Object_Altitude was 27.3 deg.
Sun_Altitude: -13.7 deg.
Moon_Altitude: -35.3, Dist. to Moon: 46.37deg.

MASTER-OAFA robotic telescope (located in Argentina , OAFA observatory of San Juan National University)
was pointed to the  MAXI GRB190305.55 1 day 38560 sec after trigger time at 2019-03-06 23:50:23 UT,
with unfiltered magnitude limit 17.5 mag.

Observations started at twilight:
Object_Altitude: 29.15deg.
Sun_Altitude: -10.7 deg.

The cover map is available at 
http://master.sai.msu.ru/static/GRB190305A/MASTERGRB190305A.jpg

We analysed Swift-XRT afterglow position (D'Ai et al. GCN 23945)
RA,Dec(2000)=00h 46m 30.38s -50d 20' 55.1".

There is no OT during MASTER alert observations, but there is  optical 
source in MASTER database on 2018-08-08 22:01:51UT with m_OT=20.1(mlim=20.3).

There is GALEX source in 1.836" ,
there is also a source in USNO-B1 in 0.982" with B2=18.08, R2=20.3 in 1984.6y.

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


GRB_name: GRB190311A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23961
SUBJECT: GRB 190311A: Swift-BAT refined analysis
DATE:    19/03/12 16:23:39 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190311A (trigger #892607)
(Troja et al., GCN Circ. 23946).  The BAT ground-calculated position is
RA, Dec = 212.067, 53.486 deg which is
  RA(J2000)  =  14h 08m 16.1s
  Dec(J2000) = +53d 29' 09.2"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 79%.

The mask-weighted light curve shows a single-pulse structure that starts
at ~T-2 s, peaks at ~T+1 s, and ends at ~T+20 s. T90 (15-350 keV) is
17.0 +- 6.8 sec (estimated error including systematics).

The time-averaged spectrum from T-2.22 to T+20.78 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.80 +- 0.17.  The fluence in the 15-150 keV band is 9.1 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.78 sec in the 15-150 keV band
is 1.8 +- 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/892607/BA/


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23962
SUBJECT: GRB 190311A: NOT optical counterpart
DATE:    19/03/12 21:47:13 GMT
FROM:    Jonatan Selsing at DARK/NBI  <jselsing@dark-cosmology.dk>

J. Selsing (DAWN/NBI), Z.P. Zhu (NAOC), D. Xu (NAOC), D. Malesani 
(DAWN/NBI, DARK/NBI), D. Nespral (IAC), D. Gandolfi (Univ. Turin), and 
J. Telting (NOT), report on behalf of a larger collaboration:

We have observed the optical afterglow of GRB 190311A (Troja et al., 
GCN 23946; Goad et al., GCN 23950; Veres & Meegan, GCN 23953) with the 
2.5-m Nordic Optical Telescope (NOT). We have obtained an r+z imaging 
sequence using the ALFOSC instrument, with 4x300 and 5x300 s exposure in 
the r and z band, respectively. Imaging observations began 9.4 hr after 
the BAT trigger.

In the images we clearly detect the optical counterpart of GRB 190311A, 
as previously reported (Zhu et al., GCN 23948; Pozanenko et al., GCN 
23947; Gorbovskoy et al., GCN 23949; Belkin et al., GCN 23951; Mao et 
al., GCN 23954; Peris & Fernandez-Soto, GCN 23959).

We calibrate the photometric zeropoints against the Pan-STARRS catalog
and derive the following magnitudes for the optical counterpart:

r = 21.88 +- 0.03 AB mag
z = 21.26 +- 0.04 AB mag

The source is centred at the position:

RA (J2000) = 14:08:15.726
DEC (J2000) = +53:30:02.74

with the astrometric solution calibrated against the 2MASS catalog.


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23963
SUBJECT: GRB 190311A: Liverpool Telescope observations
DATE:    19/03/13 09:20:05 GMT
FROM:    Martin Blazek at HETH/IAA-CSIC  <alf@iaa.es>

M. Blazek, L. Izzo. D. A. Kann (all HETH/IAA-CSIC), A. de Ugarte-Postigo (HETH/IAA-CSIC, DARK/NBI) and C. C. Thoene (HETH/IAA-CSIC) report:

We observed the Swift GRB 190311A (Troja et al, GCN 23946) with the 2-m Liverpool Telescope located in La Palma, Spain. The observation started 
at 02:19:56 UT on March 12, 2019 (t-t0 =  11.94 hours). We obtained 5x60 seconds exposures each in g', r', and i'. We clearly detected the 
optical afterglow inside the Swift-XRT error circle given of Goad et al. (GCN 23950). We measure the following magnitudes

g' = 22.18 +- 0.24 mag,
r' = 21.70 +- 0.13 mag,
i' = 21.54 +- 0.18 mag.

Magnitudes were derived against 9 nearby stars from the SDSS catalogue and are in the AB system.


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23964
SUBJECT: GRB 190311A: Mondy optical observations
DATE:    19/03/13 15:51:30 GMT
FROM:    Elena Mazaeva at IKI, Moscow  <30.v@mail.ru>

E. Mazaeva (IKI), E. Klunko (ISTP), A. Pozanenko (IKI), S. Belkin (IKI), A. Volnova (IKI) report on behalf of IKI-GRB-FuN:

We continue observations the afterglow of GRB 190311A (Troja et al. GCN 23946) with AZT-33IK telescope of Sayan observatory (Mondy) starting on Mar. 12 (UT) 16:23:42. Preliminary photometry of the afterglow detected previously (Troja et al. GCN 23946; Pozanenko et al. GCN 23947; Zhu et al. GCN 23948; Gorbovskoy et al. GCN 23949; Belkin et al. GCN 23951; Mao et al. GCN 23954; Mazaeva et al. GCN 23958; Selsing et al. GCN 23962; Blazek et al. GCN 23963) is following.

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

2019-03-12 16:23:42 1.11471  R  5400 22.16 0.09  23.5

The photometry is based on several nearby SDSS-DR12 stars used in GCN 23958.


GRB_name: GRB190311A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23965
SUBJECT: GRB 190311A: Swift/UVOT Detection
DATE:    19/03/13 16:33:25 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190311A
88 s after the BAT trigger (Troja et al., GCN Circ. 23946).
A source consistent with the XRT position (Goad et al., GCN Circ. 23950)
is detected in the initial UVOT exposures. This source is consistent
with the initial transient reported by UVOT, Mondy (Pozanenko et al., GCN
Circ. 23947), Next (Zhu et al., GCN Circ. 23948), MASTER (Gorbovskoy, GCN
Circ. 23949), TSHAO (Belkin et al., 23951), GMG (Mao et al., GCN Circ. 23954)
and OAO (Peris et al., GCN Circ. 23959). The source faded below detection by the second
orbit.

The preliminary UVOT position is:
    RA  (J2000) =  14:08:15.71 = 212.06546 (deg.)
    Dec (J2000) = +53:30:02.9  =  53.50080 (deg.)
with an estimated uncertainty of 0.49 arc sec. (radius, 90% confidence).

Preliminary detections 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               88          238          147         19.59 +/- 0.10
white             5678         7314          393            >21.42
white            51260        58205         2454            >22.45
u                  301          550          246         19.85 +/- 0.20
u                 6704        18770         1081            >21.08
b                 6910        19082          493            >20.89
v                 6089        12525         1164            >20.42
uvw1              6500        28478         1676            >20.98
uvm2              6294        23285         1557            >20.87
uvw2              5884         7521          393            >20.16

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190311A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23966
SUBJECT: GRB 190311A: OSN optical afterglow detection
DATE:    19/03/13 17:51:06 GMT
FROM:    Martin Blazek at HETH/IAA-CSIC  <alf@iaa.es>

M. Blazek, D. A. Kann, L. Izzo, C. C. Thoene (all HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), and A. Sota (IAA-CSIC) report:

We observed the Swift GRB 190311A (Troja et al, GCN 23946) with the 1.5-m telescope of the Sierra Nevada Observatory (OSN), Spain. The 
observation started at 22:54:30 on March 11, 2019 (t-t0 = 8.5158 hours). We obtained 9x360 seconds exposures each in V, Rc and Ic band. We 
clearly detect the optical afterglow inside the Swift-XRT error circle given by Goad et al. (GCN 23950). We measure the following AB magnitudes:

V  = 21.94 +- 0.17 mag     (23:31:10 - 1:54:18 UT)
Rc = 21.7  +- 0.09 mag     (23:12:50 - 1:35:58 UT)
Ic = 21.27 +- 0.15 mag     (22:54:30 - 1:16:14 UT)

Magnitudes were derived against 11 nearby stars from the SDSS catalogue, using the transformation equations of Lupton (2005), and transformed 
back into AB mags.


GRB_name: GRB190311A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23968
SUBJECT: GRB190311A: MITSuME Akeno optical observation
DATE:    19/03/15 12:11:13 GMT
FROM:    Kota Iida at Tokyo Inst. of Tech.  <kota0722iida@gmail.com>

K. Iida, R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, M. Oeda, M. Niwano, R. Adachi, Y. Yatsu,
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration

We searched for the optical counterpart of GRB 190311A (Troja et
al., GCN
Circular #23946) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50cm telescope of Akeno Observatory, Yamanashi,
Japan.

The observation started on 14:24:43.64 UT which corresponds to
70 sec after the trigger.
We detected the point source at the position consistent with the
afterglow detected previously (Troja et al. GCN #23946; Pozanenko et
al. GCN #23947; Zhu et al. GCN #23948; Gorbovskoy et al. GCN #23949,
Belkin et al. GCN #23951).
The measured magnitudes are listed as follows.

T0+[sec]    MID-UT      T-EXP[sec]        g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
~70      14:24:46.22          540              18.9+/-0.2
18.6+/-0.2     18.2+/-0.2
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the Vega system.


GRB_name: GRB190315A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23972
SUBJECT: GRB 190315A: AstroSat CZTI detection
DATE:    19/03/19 12:17:15 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, P. Ghumatkar, D. Bhattacharya, T. Khanam and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 190315A, which was also detected by Fermi/GBM (Kunzweiler F. et al., GCN # 23969).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with strongest peak at 12:17:52.500 UT. The measured peak count rate associated with the burst is 296 cts/s above the background in the combined data of four quadrants, with a total of 4402 cts. The local mean background count rate was 592 cts/s. Using cumulative rates, we measure a T90 of 31 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190320A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23973
SUBJECT: GRB 190320A: Swift detection of a burst
DATE:    19/03/20 01:47:01 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

J.D. Gropp (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
M. J. Moss (George Washington University), T. Sakamoto (AGU),
B. Sbarufatti (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 01:14:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190320A (trigger=893808).  Swift did not slew immediately 
due to an observing constraint. The BAT on-board calculated location is 
RA, Dec 117.811, -45.890 which is 
 RA(J2000) = 07h 51m 15s
 Dec(J2000) = -45d 53' 22"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  There is a data gap from ~T+10 s to ~T+100 s,
and the available data show no significant structure. However, 
since the image significance is 7.63 sigma, and the trigger is 
temporally (within ~ 20 sec) coincident with the Fermi/GBM event 
(trignum=574737261), we believe this is likely to be a real GRB. 

Due to an observing constraint, Swift will not slew until T0+44.3
minutes. There will be no XRT or UVOT data until this time. 

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: GRB190320A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23974
SUBJECT: GRB 190320A: Swift-XRT observations
DATE:    19/03/20 03:03:49 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), G. Cusumano (INAF-IASF PA), M. Perri (ASDC), P.A.
Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows
(PSU) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 190320A at 02:01:48.5 UT,
2831.9 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 117.84887,
-45.88801 which is equivalent to:
   RA(J2000)  = 07h 51m 23.73s
   Dec(J2000) = -45d 53' 16.8"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 95 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 http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data does not constrain the column density. 


GRB_name: GRB190320A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23976
SUBJECT: GRB190320A: MASTER OT detection
DATE:    19/03/20 06:47:29 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova, S.Yazev (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),


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

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, SJNU)

MASTER-OAFA automatically pointed to Swift GRB 190320A (Kennea et al. GCN 
23974, Gropp et al. GCN 23973, Lipunov et al. GCN 23975)
detected MASTER OT J075123.56-455316.54
  at position

RA,Dec(2000)=07h 51m 23.56s , -45d 53m 16.54s

Preliminary photometry is
2019-03-20 01:15:58.049 17.2
2019-03-20 01:19:25.483 17.4


GRB_name: GRB190320A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23977
SUBJECT: GRB 190320A: Enhanced Swift-XRT position
DATE:    19/03/20 07:52:54 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 303 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 190320A, 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 = 117.84813, -45.88785 which is equivalent
to:

RA (J2000): 07h 51m 23.55s
Dec (J2000): -45d 53' 16.3"

with an uncertainty of 4.5 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: GRB190320A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23978
SUBJECT: GRB 190320A: Fermi GBM observation
DATE:    19/03/20 09:00:55 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE), S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 01:14:16.49 UT on 20 March 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190320A (trigger 574737261 / 190320052),
which was also detected by the Swift/BAT (Gropp et al. 2008, GCN 23973).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 59.7 degrees.

The GBM light curve shows a structured pulse with a 
duration (T90) of about 43 s (50-300 keV).
The time-averaged spectrum from T0-4.096 s to T0+32.769 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.75 +/- 0.07 and
the cutoff energy, parameterized as Epeak, is 314 +/- 35 keV

The event fluence (10-1000 keV) in this time interval is
(6.7 +/- 0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+29.44 s in the 10-1000 keV band
is 1.93 +/- 0.17 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 296 +/- 51 keV, alpha = -0.74 +/- 0.09 and beta = -2.2 +/- 0.4. 

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

[GCN OPS NOTE(20mar19): Per author's request, the extra zero was removed
from the GRB name (in the title and the body): "1903020A" --> "190320A".]


GRB_name: GRB190320A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23979
SUBJECT: GRB190320A: MASTER GRB counterpart decay
DATE:    19/03/20 09:06:20 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, SJNU)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova, S.Yazev (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),


A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov (Kislovodsk Solar Stationof the Pulkovo Observatory),



MASTER-OAFA robotic telescope  (Global MASTER-Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,vol. 2010, 30L)
located in Argentina (OAFA observatory of San JuanNational University)
was pointed to the  Swift GRB190320A (Kennea et al. GCN 23974, Gropp et al. GCN 23973, Lipunov et al. GCN 23975)
21 sec after notice time (82 sec after trigger time) at 2019-03-20 01:15:58 UT (Lipunov et al. GCN 23975)

MASTER-OAFA find a new object MASTER OT J075123.56-455316.54 (Lipunov et al. GCN 23976)
within Swift GRB 190320A error box  (Kennea et al. GCN 23976, Osborne et al. GCN23977)
at position RA,Dec(2000)=07h 51m 23.56s , -45d 53m 16.54s (+-0.7")

MASTER OT J075123.56-455316.54 decay  by 1 magnitude during several minutes.

The reduction is continued.


GRB_name: GRB190320A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23980
SUBJECT: GRB 190320A: Swift-BAT refined analysis
DATE:    19/03/20 11:41:19 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
J.D. Gropp (PSU), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190320A (trigger #893808)
(Gropp, et al., GCN Circ.23973).  The BAT ground-calculated position is
RA, Dec = 117.824, -45.876 deg which is 
  RA(J2000)  =  07h 51m 17.8s 
  Dec(J2000) = -45d 52' 33.3" 
with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 29%.

The mask-weighted light curve shows a single episode with some superimposed
structure from roughly T-25 to T+40 sec.  The spacecraft slewed away from the 
burst position at around T+500 sec. T90 (15-350 keV) is 64.0 +- 12.1 sec 
(estimated error including systematics).

The time-averaged spectrum from T-27.20 to T+44.80 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.20 +- 0.20.  The fluence in the 15-150 keV band is 2.7 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.20 sec in the 15-150 keV band
is 1.3 +- 0.5 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/893808/BA/


GRB_name: GRB190320A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23981
SUBJECT: GRB 190320A: Swift-XRT refined Analysis
DATE:    19/03/20 11:55:11 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J.
LaPorte (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester)
and J.D. Gropp report on behalf of the Swift-XRT team:

We have analysed 6.8 ks of XRT data for GRB 190320A (Gropp et al. GCN
Circ. 23973), from 2.8 ks to 22.2 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Osborne et al. (GCN Circ. 23977).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.26 (+0.17, -0.16).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.06 (+0.33, -0.21). The
best-fitting absorption column is  3.33 (+1.48, -0.19) x 10^21 cm^-2,
consistent with the Galactic value of 3.1 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 (5.7 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.33 (+1.48, -0.19) x 10^21 cm^-2
Galactic foreground: 3.1 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.06 (+0.33, -0.21)

If the light curve continues to decay with a power-law decay index of
1.26, the count rate at T+24 hours will be 2.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.5 x
10^-14 (1.2 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/00893808.

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


GRB_name: GRB190320A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23982
SUBJECT: GRB 190320A: Swift/UVOT Upper Limits
DATE:    19/03/20 16:22:03 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190320A
2834 s after the BAT trigger (Gropp et al., GCN Circ. 23973).
No optical afterglow consistent with the XRT position
(Lipunov et al. GCN Circ. 23976)
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          2834         2984          147         >20.0
white             2834        16112         1213         >21.4
v                 2992        21862         1645         >20.4
b                 3812        15216         1082         >20.8
u                 3607         3807          197         >19.6
w1                3402         3602          197         >19.5
m2                3196        22200          524         >19.8
w2                4223        20949         1776         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.23 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190114C
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23983
SUBJECT: GRB 190114C: photometric detection of a SN component
DATE:    19/03/20 21:25:17 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>

A. Melandri (INAF-OAB), L. Izzo (HETH/IAA-CSIC), P. D'Avanzo (INAF-OAB), D. Malesani (DAWN/NBI and DARK/NBI), M. Della Valle (INAF-OAC), E. Pian (INAF-OAS), N. R. Tanvir (U. of Leicester), F. Ragosta (U. Federico II/OAC), F. Olivares (MAS/U. de Chile), R. Carini (INAF-OAR), E. Palazzi (INAF-OAS), S. Piranomonte (INAF-OAR), P. Jonker (SRON), A. Rossi (INAF-OAS), D. A. Kann (HETH/IAA-CSIC), D. Hartmann (Clemson U.), C. Inserra (Cardiff), E. Kankare (Turku), K. Maguire (QUB), S. J. Smartt (QUB), O. Yaron (Weizmann), D. R. Young (QUB), I. Manulis (Weizmann) on behalf of a larger collaboration 


We report the discovery of the supernova associated with the gamma-ray burst GRB 190114C (Gropp et al., GCN 23688) at z=0.42 (Selsing et al., GCN 23695; Castro-Tirado et al., GCN 23708; Kann et al., GCN 23710). An observational campaign lasting about 50 days has been carried out with the VLT+FORS2, the NTT+EFOSC2 and the REM+ROS2 at the European Southern Observatory (Chile), the TNG+DOLORES, the LBT+MODS2 located at Mount Graham (Arizona), and the WHT+ACAM located at the Roque de los Muchachos Observatory (Canary Islands). These observations show, at about 15 days after the burst, an apparent flattening of the afterglow light curves, in the i and z filters, in excess of the host galaxy flux, as measured in our latest epochs. This is the consistent with the emergence of a SN associated with GRB 190114C, as observed in several previous events.

By modelling the overall light curve between 0.01 and 15 days after the burst trigger (including also data from GCN circulars) with a broken power-law (afterglow contribution) + constant (host galaxy contribution), the residual fluxes in the observed i and z bands show a peak of brightness of ~23.9 and ~23.5 mag (AB), respectively. With these values we derive an estimate for the rest frame visual absolute magnitude of the SN associated with GRB 190114C of about -18 mag. This value is about 1 mag fainter than SN 1998bw (Patat et al. 2001, ApJ, 555, 900). However, the two SNe could have a comparable brightness considering the significant extinction, yet to be quantified, suffered by this event (see e.g. Kann et al., GCN 23710).

We caution that the reported values for the SN peak brightness strongly depend on the modelling of the temporal behaviour of the overall light curve. Further photometric and spectroscopic analysis is on going.

We thank the VLT, TNG, LBT and WHT staffs for executing these observations. Part of these data have been obtained under the extended Public ESO Spectroscopic Survey for Transient Objects (ePESSTO; see Smartt et al. 2015, A&A, 579, 40; http://www.pessto.org <http://www.pessto.org/>).


GRB_name: GRB190324A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23993
SUBJECT: GRB 190324A: Swift detection of a burst
DATE:    19/03/24 23:01:38 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

S. J. LaPorte (PSU), S. D. Barthelmy (GSFC), N. J. Klingler (PSU),
A. Y. Lien (GSFC/UMBC), M. J. Moss (George Washington University),
B. Sbarufatti (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 22:44:01 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190324A (trigger=894718).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 49.576, -47.239 which is 
   RA(J2000) = 03h 18m 18s
   Dec(J2000) = -47d 14' 21"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a precursor 
at ~T0 and a bright multi-peaked structure starting at ~T+19 s. 
The total duration is about 40 sec.  The peak count rate
was ~8000 counts/sec (15-350 keV), at ~21 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+52.4
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is S. J. LaPorte (extragsam 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: GRB190324A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23996
SUBJECT: GRB 190324A: Swift/UVOT afterglow candidate
DATE:    19/03/25 00:40:48 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) reports on behalf of the Neil Gehrels
Swift Observatory team:

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 3302 seconds after the BAT trigger (LaPorte et al.GCN Circ. 23993). 
There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
RA(J2000) = 03:18:27.72 = 49.61551
DEC(J2000) = -47:12:52.9 = -47.21469
with a 90%-confidence error radius of about 0.75 arc sec. 
The estimated magnitude is 17.10 with a 1-sigma error of about 0.14. 
With a single observation, we have no indication
whether the source is variable.
No correction has been
made for the expected extinction corresponding to E(B-V) of 0.02. 


GRB_name: GRB190324A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23997
SUBJECT: GRB 190324A: Swift-XRT observations
DATE:    19/03/25 00:51:49 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

M. Perri (ASDC), G. Tagliaferri (INAF-OAB), P.A. Evans (U. Leicester),
J.P. Osborne (U. Leicester), D.N. Burrows (PSU) and J.A. Kennea (PSU)
report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 190324A at 23:38:59.4 UT,
3297.9 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 49.62054,
-47.21240 which is equivalent to:
   RA(J2000)  = 03h 18m 28.93s
   Dec(J2000) = -47d 12' 44.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 145 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
http://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 (1.75 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 7
(+3.19/-2.76) x 10^21 cm^-2 (90% confidence). 


GRB_name: GRB190321A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23998
SUBJECT: GRB 190321A: Insight-HXMT/HE detection
DATE:    19/03/25 00:52:58 GMT
FROM:    QiBin Yi at IHEP, HXMT  <yiqb@ihep.ac.cn>

Q. B. Yi, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu, 
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2019-03-21T22:21:21.000 (T0), the Insight-HXMT/HE detected 
GRB 190321A (trigger ID: HEB190321931) in a routine search of the data. 

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 5.07 s measured from T0+0.65 s. 
The 1-ms peak rate, measured from T0+0.695 s, is 3598 cnts/s. 
The total counts from this burst is 7360 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190321931_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB190324A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23999
SUBJECT: GRB 190324A: VLT/X-shooter redshift
DATE:    19/03/25 02:59:34 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. A. Perley (LJMU), L. Izzo (HETH/IAA-CSIC), D. A. Kann 
(HETH/IAA-CSIC), D. B. Malesani (DAWN/NBI and DARK/NBI) report on behalf 
of the Stargate collabaration:

We observed the optical afterglow (Marshall, GCN 23996) of GRB 190324A 
(LaPorte et al., GCN 23993) using the ESO VLT UT2 (Kueyen) equipped with 
the X-shooter spectrograph. Our spectra cover the wavelength range 
3000-21000 AA, and consist of 2 exposures by 600 seconds each. The 
observation mid time was 2019 Mar 25.0441 UT (2.324 hr after the GRB).

We detect continuum at high-S/N over the entire covered wavelength 
range. A multitude of absorption features are detected, including Ca II, 
Mg II, Mg I, Fe II, Al II, Cr II, all at a common redshift z = 1.1715. 
In particular, fine structure lines from Fe II* are visible, which 
confirm the association of the absorption system with the GRB.

We acknowledge excellent support from the ESO observing staff in 
Paranal, in particular Romain Thomas, Anita Zanella, and Juan Carlos 
Olivares.


GRB_name: GRB190324A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24001
SUBJECT: GRB 190324A: Enhanced Swift-XRT position
DATE:    19/03/25 04:14:49 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1829 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 190324A, 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 = 49.61588, -47.21487 which is equivalent
to:

RA (J2000): 03h 18m 27.81s
Dec (J2000): -47d 12' 53.5"

with an uncertainty of 1.5 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: GRB190324A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24002
SUBJECT: GRB 190324A: Fermi GBM observation  
DATE:    19/03/25 04:21:58 GMT
FROM:    C. Michelle Hui at MSFC/Fermi-GBM  <c.m.hui@nasa.gov>

C. M. Hui (MSFC)

reports on behalf of the Fermi GBM Team:



At 22:44:02.64 UT on 24 March 2019, the Fermi Gamma-Ray Burst Monitor

triggered and located GRB 190324A (trigger 575160247/190324947),

which was also detected by Swift (LaPorte e al. 2019, GCN 23993).

The GBM on-ground location is consistent with the Swift position.



The GBM light curve shows an initial weak pulse followed by

a stronger signal containing two peaks. The duration (T90)

is about 26.9 s (50-300 keV). The time-averaged spectrum

from T0+15.4 s to T0+32.8 s is adequately fit by a Band function

with Epeak = 144.3 +/- 8.4 keV, alpha = -0.84 +/- 0.04,

and beta = -2.06 +/- 0.05.



The event fluence (10-1000 keV) in this time interval is

(1.78 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured

starting from T0+22.8 s in the 10-1000 keV band is 18.4 +/- 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: GRB190324A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24003
SUBJECT: GRB190324A: MASTER OT observations
DATE:    19/03/25 07:01:13 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, SJNU)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova, S.Yazev (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),

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

MASTER-OAFA robotic telescope  (Global MASTER-Net http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy,vol. 2010, 30L)
located in Argentina (OAFA observatory of San JuanNational University)
was pointed to the GRB190324A (LaPorte et al. GCN 23993, Kunzweiler et al. GCN 23994, Perri et al. GCN 23997, Beardmore et al. GCN 24001, Hui  et al. GCN 24002)
17 sec after notice time and 252 sec after trigger time at 2019-03-24 22:48:14 UT (Lipunov et al., GCN23995).

The  SunAltitude was  -1.09, so the GRB optical counterpart (MASTER OT J031827.61-471252.6 +-0.7arcsec)
light curve started at 2019-03-24  23:26:22UT (2541 sec after trigger time)
with m_OT=17.6 +-0.2(preliminary automatic light curve).

The OT became brighter (17.0) and  then shows classical decay.

This OT was also detected by Swift (Marshall et al. GCN 23996), and the spectra was observed by Perley et al. GCN23999).

MASTER-SAAO was pointed 12s after notice time, but the alert altitude was -0.6deg.

Reduction will be continued.
The message may be cited.


GRB_name: GRB190324A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24004
SUBJECT: GRB 190324A: Swift-XRT refined Analysis
DATE:    19/03/25 08:51:40 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), A.P.
Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester) and S.J. LaPorte report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 190324A (LaPorte et al. GCN
Circ. 23993), from 3.3 ks to 28.6 ks after the BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Beardmore et al. (GCN Circ. 24001).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.33 (+/-0.05).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.00 (+0.10, -0.09). The
best-fitting absorption column is  8.6 (+2.4, -2.2) x 10^20 cm^-2, in
excess of the Galactic value of 1.7 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 3.3 x 10^-11 (4.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      8.6 (+2.4, -2.2) x 10^20 cm^-2
Galactic foreground: 1.7 x 10^20 cm^-2
Excess significance: 5.0 sigma
Photon index:      2.00 (+0.10, -0.09)

If the light curve continues to decay with a power-law decay index of
1.33, the count rate at T+24 hours will be 0.032 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (1.3 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00894718.

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


GRB_name: GRB190323A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24005
SUBJECT: GRB 190323A: Insight-HXMT/HE detection
DATE:    19/03/25 12:13:39 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-23T21:05:24.000 (T0), the Insight-HXMT/HE detected
GRB 190323A(trigger ID: HEB190323878) in a routine search of the data,
which was also triggered by Fermi/GBM(F. Kunzweiler et al. ,GCN 23990).

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 42.40 s measured from T0-5.50 s.
The 1-ms peak rate, measured from T0-0.190 s, is 938 cnts/sec.
The total counts from this burst is 13490 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190323878_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190324A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24006
SUBJECT: GRB 190324A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/03/25 14:03:29 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

Y. Sone, A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito,
H. Morita (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 190324A (Swift-BAT trigger #894718: LaPorte et al.,
GCN Circ. 23993; Fermi GBM detection: Hui, GCN Circ. 24002)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 22:44:16.902 UTC
on 24 March 2019. The burst signal was seen by all CGBM detectors.

The burst light curve shows a single multi-peaked pulse which starts
at T=2.7 sec, peaks at 5.1 sec and ends at T+20.5 sec.
The precursor is not seen in the CGBM data.
The T90 and T50 durations measured by the SGM data are
12.6 +- 2.3 sec and 4.5 +- 0.5 sec (40-1000 keV), respectively.
The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1237502436/

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


GRB_name: GRB190324A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24007
SUBJECT: GRB 190324A: Swift-BAT refined analysis
DATE:    19/03/25 22:05:14 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190324A (trigger #894718)
(LaPorte et al., GCN Circ. 23993).  The BAT ground-calculated position is
RA, Dec = 49.603, -47.212 deg which is
   RA(J2000)  =  03h 18m 24.8s
   Dec(J2000) = -47d 12' 42.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 56%.

The mask-weighted light curve shows a precursor from ~T0 to ~T+5 s, and a
bright
multi-peaked structure that starts at ~T+18 s and ends at ~T+40 s. In
addition,
there are some weak emission lasting till ~T+80 s. T90 (15-350 keV)
is 28.4 +- 11.6 sec (estimated error including systematics).

The time-averaged spectrum from T+0.09 to T+83.30 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.46 +- 0.06.  The fluence in the 15-150 keV band is 7.2 +- 0.2 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+23.74 sec in the 15-150 keV band
is 11.9 +- 0.5 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/894718/BA/


GRB_name: GRB190325A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24008
SUBJECT: Fermi Trigger 575251142 / GRB 190325999 / GRB 190325A: BALROG localization
DATE:    19/03/26 05:34:10 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
575251142 at 23:58:57 on 25 March 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 286.1+/-2.5 deg
Decl.(2000.0) = 11.3+/-2.8 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190325999/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190325999/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190325999/json

                        


GRB_name: GRB190326A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24009
SUBJECT: GRB 190326A: Swift detection of a short burst
DATE:    19/03/26 07:48:18 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

M. H. Siegel (PSU), A. Y. Lien (GSFC/UMBC), K. L. Page (U Leicester)
and B. Sbarufatti (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 07:35:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190326A (trigger=895006).  Due to an observing constraint, 
Swift did not slew to the burst. The BAT on-board calculated location is 
RA, Dec 341.652, +39.903 which is 
   RA(J2000) = 22h 46m 37s
   Dec(J2000) = +39d 54' 09"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 0.1 sec.  The peak count rate
was ~7000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 12:47 UT on 2019 April 13. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is M. H. Siegel (siegel AT swift.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: GRB190326B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24010
SUBJECT: Fermi Trigger 575278303 / GRB 190326314 / GRB190326B: BALROG localization
DATE:    19/03/26 08:33:32 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
575278303 at 07:31:39 on 26 March 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 261.4+/-9.0 deg
Decl.(2000.0) = 66.5+/-2.7 deg
We estimate an additional systematic error of 2 deg.

The SWIFT BAT detection of a short GRB at 07:35:28.72 UT was most likely a different GRB.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190326314/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190326314/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190326314/json

                        


GRB_name: GRB190324A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24011
SUBJECT: GRB 190324A: Insight-HXMT/HE detection
DATE:    19/03/26 13:35:55 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-24T22:44:20.500 (T0), the Insight-HXMT/HE detected
GRB 190324A(trigger ID: HEB190324947) in a routine search of the data,
which was also triggered by Swift/BAT(S. J. LaPorte et al. ,GCN 23993),
Fermi/GBM(F. Kunzweiler et al. ,GCN 23994) and CALET/CGBM(Y. Sone 
et al. ,GCN 24006).

The Insight-HXMT/HE light curve mainly consists of two 
pulses with a duration (T90) of 6.41 s measured from T0+0.14 s.
The 1-ms peak rate, measured from T0+1.283 s, is 1111 cnts/sec.
The total counts from this burst is 3551 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190324947_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190324B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24012
SUBJECT: GRB 190324B: Insight-HXMT/HE detection
DATE:    19/03/26 13:38:15 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-24T08:21:21.000 (T0), the Insight-HXMT/HE detected
GRB 190324B(trigger ID: HEB190324348) in a routine search of the data,
which was also triggered by Fermi/GBM(J. Burgess et al. ,GCN 23992).

The Insight-HXMT/HE light curve consists of multiple 
pulses with a duration (T90) of 46.07 s measured from T0+1.05 s.
The 1-ms peak rate, measured from T0+1.952 s, is 2937 cnts/sec.
The total counts from this burst is 30168 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190324348_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190326B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24013
SUBJECT: GRB 190326B: Fermi GBM detection
DATE:    19/03/26 13:54:58 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:

"At 07:31:39.00 UT on 26 March 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190326B (trigger 575278303 / 190326314).

The on-ground calculated location, using the GBM trigger data, 
is RA = 264.2, DEC = 68.3 (J2000 degrees, equivalent
to 17h 37m, 68d 18'), with an uncertainty of 1.3 degrees 
(radius, 1-sigma containment, statistical only; there is additionally a 
systematic error which we have characterized as a core-plus-tail model, 
with 90% of GRBs having a 3.7 deg error and a small tail suffering a 
larger than 10 deg systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 21 degrees.

The GBM light curve consists of multiple pulses with a duration (T90)
of about 56 s (50-300 keV). The time-averaged spectrum from 
T0-2.048 s to T0+59.393 s is best fit by a Band function with Epeak = 163 +/- 14 keV,
alpha = -0.33 +/- 0.10, and beta = -1.93 +/- 0.07

The event fluence (10-1000 keV) in this time interval is
(1.78 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+56.5128 s in the 10-1000 keV band
is 7.8 +/- 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: GRB190324A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24014
SUBJECT: GRB 190324A: Swift/UVOT Observations
DATE:    19/03/26 16:50:58 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and S. J. LaPorte (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190324A
3302 s after the BAT trigger (LaPorte et al., GCN Circ. 23993).
A fading source consistent with the XRT position
(Beardmore et al. GCN Circ. 24001) is detected in the initial UVOT exposures,
consistent with the initial report of Marshall (GCN Circ. 23996).

The preliminary UVOT position is:
   RA  (J2000) =  03:18:27.74 =  49.61559 (deg.)
   Dec (J2000) = -47:12:52.6  = -47.21462 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections 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             3302         3452          147         17.23 +/- 0.04
white            33037        33944          885         19.65 +/- 0.07
white           101768       119129          386        >20.79
v                 3459         3659          197         17.55 +/- 0.11
v                28515        39157          496        >19.48
b                 4281         4481          197         17.98 +/- 0.07
b                10929        11267          329         18.74 +/- 0.08
b                32125        44180         1489         20.65 +/- 0.34
b               101621       118983          386        >20.13
u                 4075         4275          197         16.75 +/- 0.05
u                10016        10923          885         17.78 +/- 0.05
u                22022        22836          792         18.86 +/- 0.08
u               101474       118836          386        >19.68
uvw1              3870         4070          197         16.76 +/- 0.07
uvw1              9110        10010          885         17.65 +/- 0.07
uvw1             20525        21097          563         18.68 +/- 0.16
uvm2              3664         3864          197         16.79 +/- 0.09
uvm2             14888        15397          501         18.37 +/- 0.13
uvw2              4692         4892          197         17.82 +/- 0.12
uvw2             26341        38706         2052         19.76 +/- 0.15

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190324A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24015
SUBJECT: Konus-Wind observation of GRB 190324A
DATE:    19/03/26 16:52:58 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 190324A
(Swift-BAT detection: LaPorte et al., GCN Circ. 23993;
Fermi-GBM observation: Hui, GCN Circ. 24002;
CALET-GBM detection: Sone et al., GCN Circ. 24006; and
Insight-HXMT/HE detection: Luo et al., GCN Circ. 24011)
triggered Konus-Wind at T0=81858.644 s UT (22:44:18.644).

The burst light curve shows a multipeaked structure
which starts at ~T0-3.7 s and has a total duration of ~17.3 s,
followed by a tail of softer emission seen up to ~T0+70 s.
The initial weak pulse is marginally seen at ~T0-20 s.
The emission is seen up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190324_T81858/

As observed by Konus-Wind, the burst
had a fluence of 2.07(-0.28,+0.31)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+1.648 s,
of 7.59(-1.80,+1.86)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+16.640 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 = -0.90(-0.18,+0.22),
the high energy photon index beta = -2.27(-0.23,+0.15),
the peak energy Ep = 146(-21,+25) keV
(chi2 = 91/97 dof).

The spectrum near the maximum count rate
(measured from T0+0.256 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 = -0.90(-0.17,+0.21),
the high energy photon index beta = -2.26(-0.22,+0.15),
the peak energy Ep = 159(-23,+27) keV
(chi2 = 77/97 dof).

Assuming the redshift z=1.1715 (Perley et al., GCN Circ. 23999)
and a standard cosmology model with H_0 = 67.3 km/s/Mpc,
Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~7.8x10^52 erg,
the peak luminosity L_iso is ~6.2x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is ~317 keV.
With these energetics, the burst lies within the 68% prediction bands
for both 'Amati' and 'Yonetoku' relations built for the sample
of 138 long KW GRBs with known redshifts
(Tsvetkova et al., ApJ 850 161, 2017), see
http://www.ioffe.ru/LEA/GRBs/GRB190324_T81858/GRB190324A.pdf

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


GRB_name: GRB190326A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24016
SUBJECT: GRB 190326A: MITSuME Okayama optical upper limits
DATE:    19/03/27 06:52:18 GMT
FROM:    Masafumi Niwano at Tokyo Institute of Tech  <niwano@hp.phys.titech.ac.jp>

M. Niwano,  K. L. Murata, R. Itoh, Y. Tachibana,
K. Morita, K. Iida, K. Shiraishi, R. Adachi, M. Oeda,  Y. Yatsu,
and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration

We searched for the optical counterpart of
GRB 190326A (M. H. Siegel et al., GCN #24009)
with optical three color (g', Rc, and Ic) cameras attached to the 
MITSuME 50 cm

reflector in the Okayama Astrophysical Observatory, Japan.

The observation started at 19:01:19 UT which corresponds to 41151 
sec since the trigger.
We did not find any new point source within the Swift BAT error circle
(M. H. Siegel et al., GCN #24009) in all three bands.

The obtained 5 sigma upper limits of the optical counterpart are 
summarize below:

T0+[sec]    MID-UT      T-EXP[sec]    g'       Rc        Ic
------------------------------------------------------------------------------------------------------- 

41151  19:33:27  600   >16.8     >16.8     >16.2
------------------------------------------------------------------------------------------------------- 


T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.


GRB_name: GRB190326A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24018
SUBJECT: GRB 190326A: Insight-HXMT/HE detection
DATE:    19/03/27 14:06:40 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-26T07:35:28.900 (T0), the Insight-HXMT/HE detected
GRB 190326A(trigger ID: HEB190326316) in a routine search of the data,
which was also triggered by Swift/BAT(M. H. Siegel et al. ,GCN 24009)
and MITSuME (M. Niwano et al. ,GCN 24016).

The Insight-HXMT/HE light curve mainly consists of two 
pulses with a duration (T90) of 0.018 s measured from T0+0.01s.
The 1-ms peak rate, measured from T0+0.011 s, is 30499 cnts/sec.
The total counts from this burst is 234 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190326316_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190326B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24019
SUBJECT: GRB 190326B: Insight-HXMT/HE detection
DATE:    19/03/27 14:07:43 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-26T07:31:47.000 (T0), the Insight-HXMT/HE detected
GRB 190326B(trigger ID: HEB190326313) in a routine search of the data,
which was also triggered by Fermi/GBM(A. von Kienlin et al. ,GCN 24013).

The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 58.45 s measured from T0+0.47 s.
The 1-ms peak rate, measured from T0+48.526 s, is 3079 cnts/sec.
The total counts from this burst is 28802 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190326313_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190326A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24020
SUBJECT: GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
DATE:    19/03/27 21:08:28 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL), G. Younes (GWU)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190326A (trigger #895006)
(Siegel et al., GCN Circ. 24009).  The BAT ground-calculated position is
RA, Dec = 341.652, 39.914 deg which is
   RA(J2000)  =  22h 46m 36.6s
   Dec(J2000) = +39d 54' 50.3"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.

The mask-weighted light curve shows a FRED-like pulse structure that starts
and peaks at ~T0, and ends at ~T+0.1 s. T90 (15-350 keV) is 0.08 +- 0.03
sec
(estimated error including systematics).

The time-averaged spectrum from T+0.00 to T+0.10 sec is best fit by
a power law with an exponential cutoff.  This fit gives a photon index
-0.67 +- 0.92,
and Epeak of 33.9 +- 4.9 keV (chi squared 97.5 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 6.3 +- 0.8 x 10^-8 erg/cm2
and the 1-sec peak flux measured from T-0.45 sec in the 15-150 keV band is
1.55 +- 0.30 ph/cm2/sec. All the quoted errors are at the 90% confidence
level.

The unusually soft spectrum (for a short GRB) and the very short duration
show resemblance with an SGR. Therefore, we also compare the spectral fit
from a blackbody model, which yields a similar reduced chi square
(i.e., chi squared 99.89 for 55 d.o.f.) with kT = 9.39 keV. This kT is
consistent
with small-flare events from SGRs. However, the source location is not
really
close to the galactic plane (b = -16.9 deg), nor does it match with any
known SGRs.

If this is a GRB, this is one of the softest short bursts detected by BAT
(based on a sample with constrained spectral fits from the 3rd BAT GRB
catalog;
Lien & Sakamoto et al. 2016). Another BAT-detected short GRB with similar
softness and duration is GRB140622A, which was classified to be a short GRB
because the XRT light curve is consistent with the normal behavior of a
short burst
(Sakamoto et al. 2014; Burrows et al. 2014). Unfortunately, due to the
observing
constraint, we do not have information from XRT/UVOT, and thus it is
difficult to
determine the burst origin at this point. Further X-ray observations may
clarify the physical origin.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/895006/BA/


GRB_name: GRB190326A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24023
SUBJECT: GRB 190326A: 2.2m CAHA telescope optical limit
DATE:    19/03/28 15:59:19 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado 
(IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de 
Malaga), R. P. Hedrosa and I. Hermelo (CAHA) on behalf of a larger 
collaboration, report:

Following the detection of the short-soft event GRB 190326A by Swift 
(Siegel et al. GCNC 24009), we triggered the 2.2m telescope (+CAFOS) at 
the Spanish Calar Alto Observatory (Almeria, Spain). Observations were 
conducted at high airmass starting on March 28, 04:22:52 UT (i.e. 1.87 
day after the trigger). A series of BVRI imaging (500s per filter) shows 
no optical afterglow down to 21 mag (in the calibrated R-band image) 
within the Swift/BAT error box (1.6 arcmin, Markwardt et al. GCNC 24020).

We acknowledge excellent support from the CAHA staff.

This message can be quoted.


GRB_name: GRB190323A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24025
SUBJECT: GRB 190323A: AstroSat CZTI detection
DATE:    19/03/30 11:48:56 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, D. Bhattacharya, A. Vibhute and T. Khanam (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 190323A, which was also detected by Insight-HXMT/HE (Luo Q. et al., GCN # 24005).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with strongest peak at 21:05:40.500 UT. The measured peak count rate associated with the burst is 153 cts/s above the background in the combined data of four quadrants, with a total of 1848 cts. The local mean background count rate was 533 cts/s. Using cumulative rates, we measure a T90 of 36.6 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190330A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24026
SUBJECT: Fermi Trigger 575656777 / GRB 190330694 / GRB 190330A: BALROG localization
DATE:    19/03/30 19:23:40 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
575656777 at 16:39:32 on 30 March 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 104.3+/-2.0 deg
Decl.(2000.0) = 24.3+/-1.7 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190330694/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190330694/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190330694/json

                        


GRB_name: GRB190331A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24027
SUBJECT: GRB 190331A: Swift detection of a burst
DATE:    19/03/31 02:42:45 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

K. L. Page (U Leicester), S. D. Barthelmy (GSFC), J. A. Kennea (PSU),
N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 02:14:37.50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190331A (trigger=895813).  Swift did not slew immediately 
due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 28.576, +27.619 which is 
   RA(J2000) = 01h 54m 18s
   Dec(J2000) = +27d 37' 10"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a bright multi-peaked 
structure with a duration of about 5 sec.  The peak count rate was ~6000 
counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 18:15 UT on 2019 June 12. There will thus be no XRT or
UVOT data for this trigger before this time. 

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: GRB190329A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24029
SUBJECT: IPN Triangulation of GRB 190329A (long/bright)
DATE:    19/03/31 19:47:26 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

A. Ursi, N. Parmiggiani, F. Verrecchia, A. Bulgarelli,
A. Trois, M. Marisaldi, C. Pittori, M. Tavani, Y. Evangelista,
I. Donnarumma, M. Cardillo, G. Piano, G. Minervini, A. Argan,
F. Lucarelli, A. Zoli, V. Fioretti, F. Fuschino, M. Pilia,
F. Longo, A. Giuliani on behalf of the AGILE team, and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

The long-duration, bright GRB 190329A was detected by
Konus-Wind, Mars-Odyssey (HEND), INTEGRAL (SPI-ACS),
AGILE (MCAL), and CALET (GBM trigger 1237875481),
at about 22910 s UT (06:21:50).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   333.269 (22h 13m 05s) +19.640 (+19d 38' 25")
  Corners:
   333.369 (22h 13m 29s) +19.121 (+19d 07' 16")
   333.043 (22h 12m 10s) +20.087 (+20d 05' 13")
   333.169 (22h 12m 41s) +20.159 (+20d 09' 31")
   333.495 (22h 13m 59s) +19.194 (+19d 11' 38")
  ---------------------------------------------
The error box area is about 492 sq. arcmin, and its maximum
dimension is 1.06 deg (the minimum one is 8.04 arcmin).
The Sun distance was about 37 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190329_T22905/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB190331A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24030
SUBJECT: GRB 190331A, Swift-BAT refined analysis
DATE:    19/03/31 22:20:21 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
K. L. Page (U Leicester), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-599 to T+986 sec from the recent telemetry
downlink,
we report further analysis of BAT GRB 190331A (trigger #895813)
(Page et al., GCN Circ. 24027).  The BAT ground-calculated position is
RA, Dec = 28.573, 27.635 deg which is
   RA(J2000)  =  01h 54m 17.4s
   Dec(J2000) = +27d 38' 06.8"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.

The mask-weighted light curve shows a multi-peaked structure that starts
at ~T0 and ends at ~T+4.5. The main peak occurs at ~T0.
T90 (15-350 keV) is 4.3 +- 0.2 sec (estimated error including systematics).

The time-averaged spectrum from T-0.1 to T+4.5 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.24 +- 0.15.  The fluence in the 15-150 keV band is 4.5 +- 0.4 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T-0.06 sec in the 15-150 keV band
is 2.8 +- 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/895813/BA/


GRB_name: GRB190331B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24031
SUBJECT: GRB 190331B: Swift ToO observations
DATE:    19/04/01 00:17:21 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the Swift/BAT GRB 190331B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020885

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 Swift/BAT 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: GRB190331A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24032
SUBJECT: GRB 190331A: Fermi GBM detection
DATE:    19/04/01 00:18:35 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

S. Poolakkil (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 02:14:37.57 UT on 31 March 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190331A (trigger 575691282/ 190331093),
which was also detected by the Swift/BAT (Page et al. 2019, GCN 24027).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 40 degrees.

The GBM light curve shows multiple peaks
with a duration (T90) of about 4.8 s (50-300 keV).
The time-averaged spectrum from T0-1.0 s to T0+6.1 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.74 +/- 0.19 and
the cutoff energy, parameterized as Epeak, is 214 +/- 47 keV.

The event fluence (10-1000 keV) in this time interval is
(1.343 +/- 0.179)E-06 erg/cm^2. The 1-sec peak photon flux
measured starting from T-0.06 s in the 10-1000 keV band
is 4.6 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB190329A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24033
SUBJECT: GRB 190329A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/04/01 07:37:49 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

K. Yamaoka (Nagoya U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long bright GRB 190329A (IPN triangulation: Hurley et al.,
GCN Circ. 24029) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 06:21:49.627 UTC on 29 March 2019.
The burst signal was seen by all CGBM detectors.

The burst light curve shows two multi-peaked pulses separated by
a quiescent interval. The first pulse starts at T=0.4 sec,
peaks at 1.4 sec and ends at T+2.0 sec; the second starts at T=11.0 sec,
peaks at 11.8 sec and ends at T+16.9 sec.
The T90 and T50 durations measured by the SGM data are 14.2 +- 1.2 sec
and 10.8 +- 0.2 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1237875481/

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


GRB_name: GRB190330A
Detection_method: Fermi GBM Other
Circular_text:
:  24035
SUBJECT: GRB 190330A: Insight-HXMT/HE detection
DATE:    19/04/01 13:49:33 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-30T16:39:32.000 (T0), the Insight-HXMT/HE detected
GRB 190330A(trigger ID: HEB190330694) in a routine search of the data,
which was also triggered by Fermi/GBM(B. Biltzinger et al. ,GCN 24026).

The Insight-HXMT/HE light curve mainly consists of one
pulse with a duration (T90) of 9.28 s measured from T0-0.81 s.
The 1-ms peak rate, measured from T0+0.205 s, is 1338 cnts/sec.
The total counts from this burst is 3183 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190330694_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190331A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24036
SUBJECT: GRB 190331A: Insight-HXMT/HE detection
DATE:    19/04/01 13:50:00 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-31T02:14:38.000 (T0), the Insight-HXMT/HE detected
GRB 190331A(trigger ID: HEB190331093) in a routine search of the data,
which was also triggered by Swift/BAT(K. L. Page et al. ,GCN 24027)
and Fermi/GBM (M. Niwano et al. ,GCN 24032).

The Insight-HXMT/HE light curve mainly consists of one 
pulse with a duration (T90) of 7.65 s measured from T0+0.13 s.
The 1-ms peak rate, measured from T0+0.271 s, is 1552 cnts/sec.
The total counts from this burst is 1691 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190331093_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190331C
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24037
SUBJECT: GRB 190331C: Insight-HXMT/HE detection
DATE:    19/04/01 13:51:32 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin,
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-03-31T20:12:00.100 (T0), the Insight-HXMT/HE detected
GRB 190331C(trigger ID: HEB190331841) in a routine search of the data,
which was also triggered by INTEGRAL.

The Insight-HXMT/HE light curve mainly consists of one
pulse with a duration (T90) of 0.24 s measured from T0+0.04 s.
The 1-ms peak rate, measured from T0+0.050 s, is 4679 cnts/sec.
The total counts from this burst is 315 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190331841_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190401A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24038
SUBJECT: GRB 190401A: Insight-HXMT/HE detection
DATE:    19/04/01 13:52:10 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-04-01T03:20:21.000 (T0), the Insight-HXMT/HE detected
GRB 190401A(trigger ID: HEB190401139) in a routine search of the data,
which was also triggered by INTEGRAL(trigger_num:8247)
and Fermi/GBM (trigger_num:575781625).

The Insight-HXMT/HE light curve mainly consists of one 
pulse with a duration (T90) of 23.50 s measured from T0-1.64 s.
The 1-ms peak rate, measured from T0+0.690 s, is 1193 cnts/sec.
The total counts from this burst is 11740 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190401139_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190331B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24041
SUBJECT: GRB 190331B: Swift observations of a ground-detected burst 
DATE:    19/04/01 20:40:32 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K. L. Page (U. Leicester), D. M. Palmer (LANL) and N. P. M. Kuin
(UCL-MSSL) report on behalf of the Neil Gehrels Swift Observatory Team:

Ground processing of Swift-BAT data has discovered a possible long
duration burst, GRB 190331B, in onboard images covering 03:59:05 -
04:25:29 UT of 2019-03-31. The onboard-calculated source location is RA,
Dec = 326.258, -54.555 deg which is
 RA(J2000)  =  21h 45m 01.9s
 Dec(J2000) = -54d 33' 17.1"
As is usual for image triggers, the light curve shows no obvious
variation.  However, the source appears both in a single image covering
the time range given above, and in individual shorter images covering
subintervals, specifically 03:59:05-04:05:21; 04:05:21-04:11:21; and
04:23:37-04:25:29 The location was outside of the BAT Field of View both
before and after this time interval due to Swift's pre-planned observing
schedule, so this 26 minute span is the lower limit of the emission
interval.

Swift-XRT has performed follow-up observations of this source, collecting
2.0 ks of Photon Counting (PC) mode data between T0+73.3 ks and T0+79.0
ks.

One uncatalogued X-ray source has been detected consistent with being
within 394 arcsec of the Swift/BAT position, 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):  326.2238  =  21:44:53.71
  Dec (J2000): -54.4717  =  -54:28:18.2
  Error: 3.7 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0124 +/- 0.0030 ct s^-1
  Distance: 261 arcsec from Swift/BAT position.
  Flux: (5.5 +/- 1.3)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Another uncatalogued source was also detected, however this was too far
from the GRB position to be the afterglow.

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020885.

The Swift-UVOT observations of GRB 190331B did not find a new source,
although a source, present in the DSS near the XRT position, is also seen
in the UVOT.

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

Filter     T_start(s)  T_stop(s)   Exp(s)    3-sigma UL

white     73752     79024     283     >18.71
v       74187     74615     421     >17.35
u       73318     78999     1075     >18.73

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).

Although the gamma-ray emission duration is unusually long for a GRB, the
source's location is 45 degrees from the Galactic plane, reducing the
likelihood that this is a Galactic transient.

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: GRB190326B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24042
SUBJECT: GRB 190326B: AstroSat CZTI detection
DATE:    19/04/02 17:13:12 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, D. Bhattacharya, A. Vibhute and T. Khanam (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long bright GRB 190326B, which was also detected by Fermi-GBM (Kienlin A. von et al., GCN # 24013) and Insight-HXMT/HE detection (Luo Q. et al., GCN # 24019).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with strongest peak at 07:32:36.5 UT. The measured peak count rate associated with the burst is 418 cts/s above the background in the combined data of four quadrants, with a total of 4932 cts. The local mean background count rate was 630 cts/s. Using cumulative rates, we measure a T90 of  54.3 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190331B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24043
SUBJECT: GRB 190331B: BOOTES-3/YA optical observations
DATE:    19/04/02 21:52:40 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado 
(IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de 
Malaga), and R. Querel (NIWA), on behalf of a larger collaboration, 
report:

The 60cm BOOTES-3/YA robotic telescope at NIWA Lauder in Otago (New 
Zealand) responded to the Swift ground-detected burst GRB 190331B (Page 
et al. GCNC 24041) ~2.36 day after the burst. The first images (clear 
filter) were obtained starting on April 2, 12:39 UT. At the uncatalogued 
X-ray source position found by Swift/XRT, no optical afterglow is 
detected down to 20.3 mag on a 900s co-added image, in agreement with 
the non-detection by Swift/UVOT.

We thank the staff at NIWA for its excellent support.


GRB_name: GRB190329A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24044
SUBJECT: Konus-Wind observation of GRB 190329A
DATE:    19/04/03 12:52:21 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, bright GRB 190329A
(IPN  triangulation: Hurley et al., GCN Circ. 24029;
CALET-GBM detection: Yamaoka et al., GCN Circ. 24033)
triggered Konus-Wind at T0=22905.458 s UT (06:21:45.458).

The burst light curve shows two separated multi-peaked emission
episodes. The first episode starts at ~T0-0.3 s and
has a duration of ~2 s; the second starts at ~T0-10.3 s
and has a duration of ~8 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/GRB190329_T22905/

As observed by Konus-Wind, the burst
had a fluence of 2.20(-0.14,+0.16)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+11.168 s,
of 1.31(-0.16,+0.16)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+15.104 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.15(-0.08,+0.09)
and Ep = 345(-39,+50) keV (chi2 = 73/65 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.0
(chi2 = 73/64 dof).

The spectrum near the maximum count rate
(measured from T0+8.448 to T0+15.104 s)
is best fit in the 20 keV - 3 MeV range
by a power law with exponential cutoff model:
with  alpha = -1.01(-0.11,+0.11)
and Ep = 252(-24,+30) keV (chi2 = 80/67 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.1
(chi2 = 80/66 dof).

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


GRB_name: GRB190330A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24047
SUBJECT: GRB 190330A: MITSuME Akeno and Okayama optical upper limits
DATE:    19/04/04 13:51:36 GMT
FROM:    Adachi Ryo at Tokyo Institute of Tech  <adachi@hp.phys.titech.ac.jp>

R. Adachi, M. Niwano, K. Iida, K. L. Murata, M. Oeda,
K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We performed tiling observation for the error region of GRB 190330A
(B. Biltzinger et al., GCN Circular #24026)
with an optical tri-color (g', Rc, and Ic) camera attached to
the MITSuME 50cm telescopes at Akeno Observatory
and Okayama Astrophysical Observatory, in Japan.

The follow up observation started at 2019-03-31 10:14:29 UT, 63,297
sec after the trigger.
Our tiling observation covered almost 100% of the Fermi-GBM Ground
Position error circle
(GCN Notices Trigger num.=575656777, record num.=58).
Compared our co-added images with GSC2.3 catalog,
we found no bright optical transient in the observed region.
Because the elevation of the target field had dropped from 50 deg to 10 deg
during the observations and the sky condition was unstable,
the obtained upper limits are different for each field.
The 5-sigma upper limits of the co-added images are listed below.

Field num.   center position(R.A., Dec.)   size of field(R.A.(arcmin)
x Dec.(arcmin))   5-sigma upper limit   start observation time(UT)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Field 0    6:03:09, +16:37:06   25.5 x 25.7   g' > 18.4, Rc > 18.2, Ic
> 17.4   10:14:29  31 March
Field 1    6:04:43, +16:36:23   25.4 x 25.7   g' > 18.6, Rc > 18.2, Ic
> 17.4   11:16:01  31 March
Field 2    6:03:13, +17:01:38   23.4 x 23.6   g' > 17.2, Rc > 16.7, Ic
> 16.4   10:58:11  31 March
Field 3    6:04:46, +17:00:37   25.5 x 25.8   g' > 18.8, Rc > 18.4, Ic
> 17.4   10:55:30  31 March
Field 4    6:03:12, +16:13:33   23.6 x 23.8   g' > 17.2, Rc > 16.8, Ic
> 16.2   10:37:03  31 March
Field 5    6:01:26, +16:36:42   25.7 x 25.8   g' > 18.1, Rc > 16.7, Ic
> 16.3   10:35:00  31 March
Field 6    6:04:51, +16:13:42   23.6 x 23.8   g' > 16.9, Rc > 16.5, Ic
> 16.7   12:01:41  31 March
Field 7    6:01:23, +17:01:33   24.1 x 24.6   g' > 17.6, Rc > 17.2, Ic
> 16.3   11:57:02  31 March
Field 8    6:06:33, +16:37:22   23.3 x 23.7   g' > 17.0, Rc > 16.4, Ic
> 16.1   11:40:32  31 March
Field 9    6:03:01, +17:24:00   25.3 x 25.8   g' > 18.4, Rc > 17.9, Ic
> 17.0   11:36:32  31 March
Field 10  6:01:30, +16:13:18   22.6 x 23.8   g' > 17.1, Rc > 16.7, Ic
> 16.8   11:19:19  31 March
Field 11  6:06:19, +17:01:13   21.8 x 23.6   g' > 18.1, Rc > 17.8, Ic
> 16.8   12:58:58  31 March
Field 12  6:04:53, +17:25:24   23.6 x 23.6   g' > 16.9, Rc > 16.1, Ic
> 16.6   12:44:02  31 March
Field 13  6:06:19, +16:13:18   22.9 x 23.9   g' > 18.1, Rc > 17.5, Ic
> 16.8   12:38:20  31 March
Field 14  6:01:30, +17:25:24   22.9 x 23.7   g' > 17.0, Rc > 16.3, Ic
> 16.8   12:22:51  31 March
Field 15  6:02:59, +15:49:25   23.8 x 24.4   g' > 17.5, Rc > 17.0, Ic
> 16.5   12:17:41  31 March
Field 16  5:59:51, +16:37:12   23.2 x 24.1   g' > 15.5, Rc > 15.5, Ic
> 15.6   13:47:37  31 March
Field 17  6:04:32, +15:48:43   19.7 x 23.0   g' > 16.7, Rc > 16.7, Ic
> 16.1   13:40:16  31 March
Field 18  5:59:51, +16:37:12   23.2 x 23.7   g' > 16.1, Rc > 15.9, Ic
> 16.2   13:26:25  31 March
Field 19  6:06:18, +17:25:00   21.2 x 23.4   g' > 17.5, Rc > 16.9, Ic
> 16.1   13:19:37  31 March
Field 20  6:01:30, +15:49:24   23.2 x 23.7   g' > 16.4, Rc > 16.1, Ic
> 16.4   13:05:12  31 March
Field 21  5:59:52, +16:13:44   23.4 x 23.8   g' > 16.6, Rc > 16.4, Ic
> 16.6   10:24:38    1 April
Field 22  6:08:11, +16:37:38   23.6 x 23.7   g' > 16.6, Rc > 16.5, Ic
> 16.8   10:45:45    1 April
Field 23  6:03:13, +17:49:19   23.5 x 23.7   g' > 15.5, Rc > 15.2, Ic
> 15.2   14:08:53  31 March
Field 24  6:08:14, +17:01:33   23.3 x 23.7   g' > 16.6, Rc > 16.5, Ic
> 16.7   11:06:53    1 April
Field 25  6:04:33, +17:48:39   19.1 x 22.7   g' > 17.0, Rc > 17.0, Ic
> 16.4   13:51:43  31 March
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

We used GSC2.3 and UCAC4 catalog for flux calibration.


GRB_name: GRB140404B
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24048
SUBJECT: GRB 140404B: MAXI/GSC detection
DATE:    19/04/04 14:26:08 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

M. Nakajima, H. Negoro (Nihon U.), W. Iwakiri (Chuo U.), 
W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), 
S. Nakahira, T. Mihara, M. Matsuoka (RIKEN), 
T. Sakamoto, M. Serino, S. Sugita, T. Hashimoto, A. Yoshida (AGU), 
Y. Tsuboi, R. Sasaki, H. Kawai, T. Sato (Chuo U.), N. Kawai, M. Sugizaki, 
Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi (Tokyo Tech), 
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai, 
M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, 
S. Ogawa (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.), 
M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.), Y. Kawakubo (LSU)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray 
transient source at 12:24:20 UT on 2019 April 4. Assuming that the source 
flux was constant over the transit, we obtain the source position at
(R.A., Dec) = (12.088 deg, 27.486 deg) = (00 48 21, +27 29 09) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.13 deg and 0.12 deg, respectively.
The roll angle of the long axis from the north direction is 136.0 deg 
counterclockwise. 
  Without assumptions on the source constancy, we obtain a rectangular error box
for the transient source with the following corners: 
(12.621, 28.061) deg = (00 50 29, +28 03 39) (J2000) 
(12.378, 28.204) deg = (00 49 30, +28 12 14) (J2000) 
(11.610, 27.173) deg = (00 46 26, +27 10 22) (J2000) 
(11.851, 27.032) deg = (00 47 24, +27 01 55) (J2000)
There is an additional systematic uncertainty of 0.1 deg (90% containment 
radius).

The X-ray flux averaged over the scan was 399 +- 41 mCrab (4.0-10.0keV, 
1 sigma error). There was no significant excess flux in the previous transit 
at 10:51 UT on 2019 April 4 with an upper limit of 20 mCrab.

Note that we noticed that Fermi had detected a GRB at 07:01 on April 4.
Then, we rename this burst, referred to as GRB 190304A in the MAXI 
new-transient ML, GRB 190404B. We apologize for a series of mistakes.


GRB_name: GRB140404C
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24049
SUBJECT: GRB 140404C: MAXI/GSC detection
DATE:    19/04/04 14:47:32 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

S. Yamada (Kyoto U.), H. Negoro, M. Nakajima (Nihon U.), W. Iwakiri (Chuo, U.), 
W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.), T. Mihara, S. Nakahira, 
M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, T. Hashimoto, A. Yoshida (AGU), 
Y. Tsuboi,  R. Sasaki, H. Kawai, T. Sato (Chuo U.), N. Kawai, M. Sugizaki, 
Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi (Tokyo Tech), S. Ueno, H. Tomida, 
M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai, M. Tominaga (JAXA), 
Y. Ueda, A. Tanimoto, T. Morita, S. Ogawa (Kyoto U.), H. Tsunemi, 
T. Yoneyama, K. Asakura, S. Ide (Osaka U.), M. Yamauchi, S. Iwahori, 
Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), 
M. Shidatsu (Ehime U.), Y. Kawakubo (LSU)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray transient 
source at 13:14:08 UT on 2019 April 04.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (220.987 deg, -22.632 deg) = (14 43 56, -22 37 55) (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 the long axis from the north direction is 67.0 deg counterclockwise. 
Without assumptions on the source constancy, we obtain a rectangular error box
for the transient source with the following corners: 
(221.159, -22.965) deg = (14 44 38, -22 57 53) (J2000) 
(221.325, -22.771) deg = (14 45 17, -22 46 15) (J2000) 
(220.273, -22.002) deg = (14 41 05, -22 00 07) (J2000) 
(220.107, -22.196) deg = (14 40 25, -22 11 45) (J2000) 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 378 +- 40 mCrab (4.0-10.0keV, 1 sigma error).

There was no significant excess flux in the previous transit at 11:41 UT with an upper limit of 20 mCrab.
Note that we rename GRB 190404B in the MAXI new-transient ML GRB 190404C.


GRB_name: GRB190404B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24050
SUBJECT: GRB 190404B: Tiled Swift observations
DATE:    19/04/04 15:17:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 190404B. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00079

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: GRB190404C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24051
SUBJECT: GRB190404C: GROWTH-India discovery of optical counterpart
DATE:    19/04/04 20:27:13 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

Gaurav Waratkar(IITB), Harsh Kumar (IITB), Viraj Karambelkar (IITB), Tsewang Stanzin (IAO, IIA), Varun Bhalerao (IITB), G.C. Anupama (IIA) report on behalf of the GROWTH-India collaboration:

We observed the uncertainty region of GRB190404C (Yamada et al, GCN 24049) at UT 18:08:20 UT corresponding to 4.9 hrs after the alert and obtained an r band image of 600 seconds. We find a new uncatalogued source within the MAXI 90% confidence region:

T - T0   |  RA (J2000) | Dec (J2000) | Filt. | Magnitude |
4.9 hrs    14:44:00.896  -22:40:33.02    r    19.62 +/- 0.13 

The source has faded out in a subsequent image obtained at UT 19:47. Further observations are under way.

GROWTH India telescope is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).


GRB_name: GRB190331B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24052
SUBJECT: Swift GRB 190331B: Further Swift-XRT observations
DATE:    19/04/05 06:42:53 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K.L. Page (U. Leicetser) reports on behalf of the Swift-XRT team:

Swift has performed a second follow-up observation of the ground-detected
Swift-BAT GRB 190331B (Page et al., GCN Circ. 24041). An additional 2.7 ks
of data were collected, entirely in Photon Counting mode, 334.5 ks after
the trigger time

The count rate of the possible afterglow counterpart ("Source 1")
mentioned in GCN Circ. 24041 remains constant across both observations, at
about 0.01 ct s^-1. We therefore conclude that we did not detect an X-ray
afterglow for GRB 190331B.

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


GRB_name: GRB190331C
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24053
SUBJECT: GRB 190331C: AstroSat CZTI detection
DATE:    19/04/05 12:15:21 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, D. Bhattacharya, A. Vibhute and T. Khanam (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a short GRB 190331C, which was also detected by Insight-HXMT/HE detection (Luo Q. et al., GCN # 24037).

The source was clearly detected in the 40-200 keV energy range. The light curve shows single peak of emission at 20:12:00.155 UT. The measured peak count rate associated with the burst is 2002 cts/s above the background in the combined data of four quadrants, with a total of 1648 cts. The local mean background count rate was 498 cts/s. Using cumulative rates, we measure a T90 of 0.16 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190404C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24054
SUBJECT: GRB 190404C: Swift-XRT observations
DATE:    19/04/05 15:16:19 GMT
FROM:    Valerio D'Elia at ASDC  <valerio.delia@ssdc.asi.it>

P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC),
A. D'Ai (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 190404C (Yamada et al. 2019, GCN circ. 24049)in a series of
observations tiled on the sky. The total exposure time is 4.9 ks,
distributed over 4 tiles; the maximum exposure at a single sky location
was 3.4 ks. The data were collected between T0+7.4 ks and T0+19.1 ks,
and are entirely in Photon Counting (PC) mode. 

Three uncatalogued X-ray sources have been detected, however none of
them is above the RASS limit. No source shows definitive signs of
fading, despite Source 3, which is the brightest, marginally weakened
(at the 2.7 sigma level) during the observation. Therefore, at the
present time we cannot safely identify the afterglow. Details of these
sources are given below:

Source 1:
  RA (J2000):  221.0760  =  14:44:18.23
  Dec (J2000): -22.6488  =  -22:38:55.5
  Error: 6.1 arcsec (radius, 90% conf.)
  Count-rate: (6.3 [+3.2, -2.4])e-3 ct s^-1   
  Distance: 1015 arcsec from MAXI position.
  Flux: (3.0 [+1.5, -1.1])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000):  221.0110  =  14:44:2.63
  Dec (J2000): -22.5140  =  -22:30:50.3
  Error: 13.5 arcsec (radius, 90% conf.)
  Count-rate: (6.8 [+3.8, -2.8])e-3 ct s^-1   
  Distance: 1006 arcsec from MAXI position.
  Flux: (5.4 [+3.0, -2.2])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000):  220.84256  =  14:43:22.21
  Dec (J2000): -22.66386  =  -22:39:49.9
  Error: 2.8 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0236 [+0.0041, -0.0038] ct s^-1   
  Distance: 245 arcsec from MAXI position.
  Flux: (5.99 [+1.03, -0.98])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


We do not find any X-ray object at the position of the optical
candidate reported by Waratkar et al. 2019 (GCN circ. 24051), the
closest source being Source 1 at a distance of 4.3 arcmin. The XRT
upper limit at the position of the GROWTH candidate is ~7e-3 ct s^-1.
The UVOT upper limit at the same position is ~ 21 mag in the U band.

The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00079.

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


GRB_name: GRB190404B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24055
SUBJECT: GRB 190404B: CALET Gamma-Ray Burst Monitor detection
DATE:    19/04/05 23:02:04 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

S. Nakahira (RIKEN),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 190404B (MAXI/GSC detection: Nakajima et al., GCN Circ. 24048)
was detected in ground analysis of the CALET Gamma-ray Burst Monitor (CGBM)
data near the MAXI trigger time at T0=12:24:20 UTC on 4 April 2019.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a single multi-peaked emission episode
which starts at T-15.1 sec and ends at T+80.4 sec.
The T90 and the T50 durations measured by the SGM data are
87.5 +- 18.8 sec and 47.6 +- 17.5 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1238415870/

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


GRB_name: GRB190404C
Detection_method: retraction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24056
SUBJECT: GRB190404C: Counterpart retraction
DATE:    19/04/06 03:35:57 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

Gaurav Waratkar(IITB), Harsh Kumar (IITB), Viraj Karambelkar (IITB), Tsewang Stanzin (IAO, IIA), Varun Bhalerao (IITB), G.C. Anupama (IIA) report on behalf of the GROWTH-India collaboration:

Further analysis of GROWTH-India data reveals that the reported object is actually not a counterpart, but asteroid 2010 FQ3. A fainter object seen in subsequent images was a background star. We hereby retract GCN 24051.


GRB_name: GRB190407A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24057
SUBJECT: Fermi Trigger 576346051 / GRB 190407672 / GRB 190407A: BALROG localization
DATE:    19/04/07 16:31:40 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
576346051 at 16:07:26 on 07 April 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 175.1+/-2.9 deg
Decl.(2000.0) = 41.8+/-3.1 deg
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190407672/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190407672/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190407672/json

                        


GRB_name: GRB190404C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24062
SUBJECT: GRB 190404C: Swift-XRT afterglow detection
DATE:    19/04/08 14:57:46 GMT
FROM:    Valerio D'Elia at ASDC  <valerio.delia@ssdc.asi.it>

P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia (ASDC),
A. D'Ai (INAF-IASFPA) and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
MAXI-detected burst GRB 190404C  (Yamada et al., GCN Circ. 24049). The
observations now extend from T0+7.4 ks to T0+335.5 ks. 

Of the sources reported by D'Avanzo et al. (GCN Circ. 24054), "Source
3" is fading with 3-sigma significance, and is therefore likely the GRB
afterglow. Using 1249 s of PC mode data and 2 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 = 220.84256, -22.66386
which is equivalent to:

RA (J2000): 14h 43m 22.21s
Dec(J2000): -22d 39' 49.9"

with an uncertainty of 2.8 arcsec (radius, 90% confidence). This
position is 4.1 arcmin from the MAXI position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.72 (+0.39, -0.22).

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020887.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00079.

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


GRB_name: GRB140408A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24072
SUBJECT: GRB 140408A: MAXI/GSC detection
DATE:    19/04/09 01:14:21 GMT
FROM:    Satoshi Sugita at Aoyama Gakuin U.  <sugita@phys.aoyama.ac.jp>

S. Sugita (AGU), H. Negoro, M. Nakajima, W. Maruyama, M. Aoki, K.
Kobayashi (Nihon U.),
S. Nakahira, T. Mihara, M. Matsuoka (RIKEN),
T. Sakamoto, M. Serino, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.),
M. Shidatsu (Ehime U.),
N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi
(Tokyo Tech),
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai,
M. Tominaga (JAXA),
Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.),
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.),
M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.),
T. Kawamuro (NAOJ),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray
transient source at UT 2019/04/08 18:06:19.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (47.342 deg, 1.758 deg) = (03 09 22, +01 45 28) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.52 deg and 0.22 deg, respectively.
The roll angle of long axis from the north direction is 145.0 deg
counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90%
containment radius).
The X-ray flux averaged over the scan was 189 +- 35 mCrab
(2.0-4.0keV, 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) = (46.050, 1.531) deg = (03 04 11, +01 31 51) (J2000)
(R.A., Dec) = (46.579, 0.646) deg = (03 06 18, +00 38 45) (J2000)
(R.A., Dec) = (48.900, 2.032) deg = (03 15 35, +02 01 55) (J2000)
(R.A., Dec) = (48.371, 2.917) deg = (03 13 29, +02 55 01) (J2000)
There was no significant excess flux in the previous transit at UT 16:33
and in the next transit at UT 19:39 with an upper limit of 20 mCrab for each.


GRB_name: GRB190408A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24073
SUBJECT: CORRECTED TARGET NAME: GRB 190408A: MAXI/GSC detection
DATE:    19/04/09 01:32:24 GMT
FROM:    Satoshi Sugita at Aoyama Gakuin U.  <sugita@phys.aoyama.ac.jp>

S. Sugita (AGU), H. Negoro, M. Nakajima, W. Maruyama, M. Aoki, K.
Kobayashi (Nihon U.),
S. Nakahira, T. Mihara, M. Matsuoka (RIKEN),
T. Sakamoto, M. Serino, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.),
M. Shidatsu (Ehime U.),
N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi
(Tokyo Tech),
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai,
M. Tominaga (JAXA),
Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, S. Ogawa (Kyoto U.),
H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.),
M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.),
T. Kawamuro (NAOJ),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray
transient source at UT 2019/04/08 18:06:19.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (47.342 deg, 1.758 deg) = (03 09 22, +01 45 28) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.52 deg and 0.22 deg, respectively.
The roll angle of long axis from the north direction is 145.0 deg
counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90%
containment radius).
The X-ray flux averaged over the scan was 189 +- 35 mCrab
(2.0-4.0keV, 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) = (46.050, 1.531) deg = (03 04 11, +01 31 51) (J2000)
(R.A., Dec) = (46.579, 0.646) deg = (03 06 18, +00 38 45) (J2000)
(R.A., Dec) = (48.900, 2.032) deg = (03 15 35, +02 01 55) (J2000)
(R.A., Dec) = (48.371, 2.917) deg = (03 13 29, +02 55 01) (J2000)
There was no significant excess flux in the previous transit at UT 16:33
and in the next transit at UT 19:39 with an upper limit of 20 mCrab for each.


GRB_name: GRB190409A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24081
SUBJECT: GRB 190409A: Swift detection of a possible burst
DATE:    19/04/09 14:16:59 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

A. D'Ai (INAF-IASFPA), S. D. Barthelmy (GSFC),
M. G. Bernardini (INAF-OAB), D. N. Burrows (PSU), V. D'Elia (SSDC),
P. A. Evans (U Leicester), J.D. Gropp (PSU), J. A. Kennea (PSU),
N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL),
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU),
M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 13:01:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located possible GRB 190409A (trigger=897653).  Swift did not immediately slew
due to an observing constraint.  The BAT on-board calculated location is 
RA, Dec 324.921, -46.607, which is 
   RA(J2000)  =  21h 39m 41s
   Dec(J2000) = -46d 36' 25"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, the real-time
light curve does not show anything significant. 

The XRT began observing the field at 13:50:28.1 UT, 2946.9 seconds
after the BAT trigger. No source was detected in 1.2 ks of promptly
downlinked data, which covered 55% of the BAT error circle. We are
waiting for the full dataset to detect and localise the XRT
counterpart. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 2950 seconds after the BAT trigger. No credible afterglow candidate
has been found in the initial data products. Results from the 2.7'x2.7'
sub-image are not available at this time. The 8'x8' region for the list of
sources generated on-board covers 100% of the BAT 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 0.02. 

Burst Advocate for this burst is A. D'Ai (antonino.dai 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: GRB190404B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24083
SUBJECT: Konus-Wind observation of GRB 190404B
DATE:    19/04/09 16:28:57 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long GRB 190404B which triggered MAXI/GSC at 12:24:20 UT
(MAXI/GSC detection: Nakajima et al., GCN 24048;
CALET Gamma-Ray Burst Monitor detection: Nakahira et al., GCN 24055)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows a single multi-peaked emission episode
started at ~T0(MAXI)-7.4 s with a total  duration of ~85.4 s.

As observed by Konus-Wind, the burst had a fluence of
5.57(-1.00,+1.34)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(MAXI)+51.5 s, of 1.09(-0.20,+0.26)x10^-7 erg/cm2/s
(both in the 20 - 1200 keV energy range).

Fitting the K-W 3-channel time-integrated spectrum
(from ~T0(MAXI)-7.4 s to ~T0(MAXI)+78.0 s) in the 20 keV - 1.2 MeV range
by a power law with exponential cutoff model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields
alpha = -1.64(-0.36,+3.80),
and Ep =80(-39,+33) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB190404B/


GRB_name: GRB190404C
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24089
SUBJECT: GRB 190404C: MITSuME Akeno and Okayama optical upper limits
DATE:    19/04/10 11:53:08 GMT
FROM:    Adachi Ryo at Tokyo Institute of Tech  <adachi@hp.phys.titech.ac.jp>

R. Adachi, M. Niwano, K. L. Murata, K. Iida, M. Oeda,
K. Shiraishi, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We performed tiling observation for the error region of GRB 190404C
(S. Yamada et al., GCN Circular #24049)
with an optical tri-color (g', Rc, and Ic) camera attached to
the MITSuME 50cm telescopes at Akeno Observatory
and Okayama Astrophysical Observatory, in Japan.

The follow up observation started at 2019-04-04 13:36:27 UT, 1,339 sec
after the trigger.
Our tiling observation covered almost 95% of the MAXI/GSC error box
(S. Yamada et al., GCN Circular #24049).

We did not find any new point source within the Swift XRT error circle
(P. D'Avanzo et al. GCN #24054, #24062) in all three bands.
Since the brightness source near the XRT error circle(~9 arcsec), the
obtained upper limit is very shallow.
The obtained 5 sigma upper limits of the optical counterpart are
summarize below:

T0+[sec]    MID-UT      T-EXP[sec]        g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
1339      13:42:06          480              >13.1  >12.4    >11.9
-------------------------------------------------------------------------------------------------------


Furthermore, compared our co-added images with GSC2.3 catalog and
UCAC4 catalog, we found no bright optical transient in the observed
region.
Because the sky condition was unstable, the obtained upper limits are
different for each field.
The 5-sigma upper limits of the co-added images are listed below.

Field num.   center position(R.A., Dec.)   size of field(R.A.(arcmin)
x Dec.(arcmin))   5-sigma upper limit   start observation time(UT)
--------------------------------------------------------------------------------------------
Field 1    14:42:36, -22:46:14   25.7 x 25.9   g' > 17.0, Rc > 17.2,
Ic > 17.1   13:36:27
Field 2    14:43:08, -22:37:04   25.7 x 25.9   g' > 17.4, Rc > 17.6,
Ic > 17.4   13:47:51
Field 3    14:43:03, -22:14:27   26.0 x 25.0   g' > 17.8, Rc > 18.0,
Ic > 17.5   14:47:19
Field 4    14:44:50, -22:41:11   23.3 x 23.7   g' > 15.6, Rc > 15.6,
Ic > 15.7   14:47:06
Field 5    14:41:24, -22:15:23   23.3 x 24.3   g' > 18.0, Rc > 18.0,
Ic > 17.5   16:24:11
Field 6    14:42:17, -22:30:00   24.0 x 23.6   g' > 18.1, Rc > 18.1,
Ic > 17.5   17:57:11
Field 7    14:43:12, -22:17:05   25.4 x 25.7   g' > 17.2, Rc > 17.3,
Ic > 17.1   15:46:23
Field 8    14:44:14, -22:27:57   25.8 x 25.9   g' > 17.7, Rc > 17.3,
Ic > 16.9   18:25:06
Field 9    14:41:18, -22:20:50   25.4 x 25.7   g' > 17.6, Rc > 17.7,
Ic > 17.1   19:28:34
Field 10  14:43:18, -22:41:18   23.3 x 23.7   g' > 18.4, Rc > 18.4,
Ic > 17.7   15:25:47
--------------------------------------------------------------------------------------------

We used UCAC4 catalog for flux calibration.


GRB_name: GRB190408A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24091
SUBJECT: LIGO/Virgo S190408an: MAXI/GSC Observations
DATE:    19/04/10 14:06:38 GMT
FROM:    Hitoshi Negoro at Nihon U  <negoro@cygnus.phys.cst.nihon-u.ac.jp>

H. Negoro (Nihon U.), M. Serino, S. Sugita (AGU), M. Sugizaki, N. Kawai (Tokyo Tech),
M. Nakajima, W. Maruyama, M. Aoki, K. Kobayashi (Nihon U.),
S. Nakahira, T. Mihara, M. Matsuoka (RIKEN), T. Sakamoto, A. Yoshida (AGU),
Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, T. Sato (Chuo U.), M. Shidatsu (Ehime U.), 
Y. Tachibana, K. Morita, M. Oeda, K. Shiraishi (Tokyo Tech), 
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N.Isobe, R. Shimomukai,
M. Tominaga (JAXA), Y. Ueda, A. Tanimoto, T. Morita, S. Yamada, 
S. Ogawa (Kyoto U.), H. Tsunemi, T. Yoneyama, K. Asakura, S. Ide (Osaka U.),
M. Yamauchi, S. Iwahori, Y. Kurihara (Miyazaki U.), T. Kawamuro (NAOJ),
K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU)
report on behalf of the MAXI team:

At the LVC trigger time of S190408an, 18:18:02.29 UT on 2019 April 8 
(LIGO/Virgo Collaboration, GCN Circ. 24069), MAXI/GSC was scanning a part of 
the 50% credible region, centered around (R.A., Dec) = (333 deg, 20 deg),
but no flaring event was detected.
For one orbital period about 92 min, MAXI covered about 82% of the 90% 
credible region. Any enhancement was recognized in the region, and a typical 
(averaged) 1-sigma upper limit was 28 mCrab at 2-20 keV. MAXI observed 
the whole 90% credible region in 6 hours, and we put upper limits
of typically about 15 mCrab, and partially about 50 mCrab for the regions 
observed with the degraded GSC_3 camera.

Finally we note that MAXI detected GRB 190408A prior to the LVC trigger by 
12 min (Sugita et al. GCN Circ. 24072). The burst was relatively short 
(~ 10 sec) and soft, but the GRB location, (R.A., Dec) = (47.3 deg, 1.8 deg), 
is far from the GW localization region.
Thus, an association between these events is likely low.


GRB_name: GRB190409A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24093
SUBJECT: GRB 190409A: ground analysis reveals a likely spurious event
DATE:    19/04/10 14:55:51 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

A. D'Ai (INAF-IASFPA), A. Y. Lien (GSFC/UMBC), A. A. Breeveld (MSSL-UCL)
report on behalf of the Swift team:

Using Swift/BAT data set from T-60 to T+243 sec from 
the recent telemetry downlink, we report further 
analysis of the possible GRB 190409A (trigger #897653,
D'Ai et al. GCN 24081). The BAT image significance has 
decreased to 3.7 sigma, and thus is consistent with 
a noise fluctuation.

We have analysed 2.8 ks of Photon Counting (PC) mode 
XRT  data, collected between T0+3.0 ks and T0+10.2 ks. 
One uncatalogued X-ray source has been detected but 
outside the BAT error circle at 4.3 arcmin from the Swift/BAT  
position reported in GCN 24081. The source is below the RASS 
limit and shows no definitive signs of fading. Details of this source 
are given below:

Source 1:
 RA (J2000):  325.0326  =  21:40:7.82
 Dec (J2000): -46.6064  =  -46:36:23.0
 Error: 7.7 arcsec (radius, 90% conf.)
 Count-rate: (4.3 [+1.8, -1.4])e-3 ct s^-1   
 Distance: 276 arcsec from Swift/BAT position.

The Swift/UVOT began settled observations of the field of GRB 190409A
with the white filter 2950 s after the BAT trigger (D'Ai et al., GCN Circ. 24081). 
No optical afterglow is detected in the initial UVOT  exposure.

Given the lowered significance of the BAT trigger from the ground
analysis, the lack  of a clear X-ray/UVOT counterpart within the 
BAT error circle,  we believe that GRB 190409A was most likely 
a spurious event.


GRB_name: GRB190409B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24095
SUBJECT: IPN triangulation of GRB 190409B (short)
DATE:    19/04/11 00:15:09 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin and K. Hurley, on behalf of the IPN,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

The short-duration GRB 190409B was detected
by Fermi (GBM trigger 576538690), INTEGRAL (SPI-ACS),
and Swift (BAT), at about 77885 s UT (21:38:05).
The burst was outside the coded field of view of the BAT.

We have triangulated this GRB to a GBM-INTEGRAL annulus centered at 
RA(2000)=258.187 deg (17h 12m 45s) Dec(2000)=+48.305 deg (+48d 18' 19"), 
whose radius is 89.659(-6.155,+2.958) deg (3 sigma).

The annulus reduces the area of the 2 sigma Fermi-GBM final position
(glg_healpix_all_bn190409901_v00) by about a factor of 5.

This annulus may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190409_T77885/IPN


GRB_name: GRB190411A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24117
SUBJECT: GRB 190411A: Insight-HXMT/HE detection
DATE:    19/04/13 12:22:06 GMT
FROM:    Ce Cai at IHEP  <caice@ihep.ac.cn>

C. Cai, C. K. Li, X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 
report on behalf of the Insight-HXMT team: 

At 2019-04-11T09:45:46.000 (T0), the Insight-HXMT/HE detected 
GRB 190411A (trigger ID: HEB190411406) in a routine search of the data, 
which was also triggered by Fermi/GBM (trigger number 576668753);

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 34.10 s measured from T0+2.32 s. 
The 1-s peak rate, measured from T0+4.50 s, is 19416 cnts/s. 
The total counts from this burst is 110320 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190411406_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (record energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
fundedjointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information could be found at: http://www.hxmt.org.


GRB_name: GRB190411A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24118
SUBJECT: GRB 190411A: AstroSat CZTI detection
DATE:    19/04/13 13:57:05 GMT
FROM:    Tanazza Khanam at IUCAA  <tanazza@iucaa.in>

T. Khanam, V. Sharma, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 190411A, which was also detected by Insight-HXMT/HE detection (Cai C. et al., GCN # 24117).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with strongest peak at 09:45:52.5 UT. The measured peak count rate associated with the burst is 3857.37 cts/s above the background in the combined data of four quadrants, with a total of 40446 cts. The local mean background count rate was 321.6 cts/s. Using cumulative rates, we measure a T90 of 42.7 s. In preliminary analysis, we find that 3004 Compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190404A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24120
SUBJECT: Corrections: GRB 190404A (not 140404B ) and GRB 190404B (not 140404C)
DATE:    19/04/14 10:09:59 GMT
FROM:    Hitoshi Negoro at Nihon U  <negoro.hitoshi@nihon-u.ac.jp>

H. Negoro (Nihon U.) report on behalf of the MAXI team:

The GRB names of 140404B/190404B (Nakajima et al. GCN Circ. 24048) and 
140404C/190404C (Yamada et al. GCN Circ. 24049) should be 190404A and 190404B, respectively.
I sincerely apologize for the late correction and for any confusion caused. 


GRB_name: GRB190407B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24121
SUBJECT: GRB 190407B: AstroSat CZTI detection
DATE:    19/04/15 02:07:35 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, D. Bhattacharya, A. Vibhute and T. Khanam (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a GRB 190407B, which was also detected by Fermi/GBM (Biltzinger B. et al., GCN # 24059).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 18:54:42.500 UT. The measured peak count rate associated with the burst is 662 cts/s above the background in the combined data of four quadrants, with a total of 1147 cts. The local mean background count rate was 638 cts/s. Using cumulative rates, we measure a T90 of 2.3 s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190415A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24125
SUBJECT: GRB 190415A: Insight-HXMT/HE detection
DATE:    19/04/16 03:18:40 GMT
FROM:    Qi Luo at IHEP  <luoqi@ihep.ac.cn>

Q. Luo, C. Cai, S. Xiao, Q. B. Yi, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-04-15T04:09:49.900 (T0), the Insight-HXMT/HE detected
GRB 190415A(trigger ID: HEB190415173) in a routine search of the data,
which was also triggered by Fermi/GBM(F. Kunzweiler et al. ,GCN 24123)
and INTEGRAL.

The Insight-HXMT/HE light curve mainly consists of multiple 
pulses with a duration (T90) of 24.74 s measured from T0+0.89 s.
The 1-ms peak rate, measured from T0+4.001 s, is 17011 cnts/sec.
The total counts from this burst is 100520 counts.
URL_LC: http://www.hxmt.org/images/GRB/HEB190415173_lc.jpg

All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.

Insight-HXMT is the first Chinese space X-ray telescope, which was
fundedjointly by the China National Space Administration (CNSA) and
the Chinese Academy of Sciences (CAS).
More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB190415A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24128
SUBJECT: IPN Triangulation of GRB 190415A
DATE:    19/04/18 16:25:31 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

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

The long-duration GRB 190415A
(Insight-HXMT/HE detection: Luo et al., GCN Circ. 24125)
was detected by Fermi (GBM trigger 576994194),
INTEGRAL (SPI-ACS), Konus-Wind, Swift (BAT), and Insight (HXMT/HE)
at about 14990 s UT (04:09:50).
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:
    28.053 (01h 52m 13s) +20.221 (+20d 13' 16")
  Corners:
    26.606 (01h 46m 25s) +21.774 (+21d 46' 27")
    27.221 (01h 48m 53s) +22.093 (+22d 05' 34")
    29.374 (01h 57m 30s) +18.606 (+18d 36' 22")
    28.770 (01h 55m 05s) +18.296 (+18d 17' 44")
  ---------------------------------------------
The error box area is about 2.6 sq. deg, and its maximum
dimension is 4.1 deg (the minimum one is 39 arcmin).
The Sun distance was about 10 deg.

This box may be improved.

The box lies outside the 1 sigma of the alternative
localization of the Fermi-GBM detection BALROG
(Kunzweiler et al., GCN Circ. 24123; ~0.6 deg stat. + 1 deg sys.),
while being consistent with 1 sigma contours of the Fermi-GBM final
position.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190415_T14986/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB190326A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24129
SUBJECT: GRB 190326A: Swift XRT and UVOT follow-up observations 
DATE:    19/04/18 17:20:09 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

B. Sbarufatti (PSU), P. Kuin (MSSL/UCL) and M. H. Siegel (PSU) report on behalf of the Swift-XRT team:

Swift has performed XRT and UVOT follow-up observations of BAT detected GRB 190326A (Siegel et al. GCN Circ. 24009), after it came out of the Sun observing constraint.
The data were collected between T0+18.91 days and T0+18.98 days, for a total exposure of 1.9 ks in Photon Counting (PC) mode for XRT and with the UVW1 filter for UVOT.

No uncatalogued X-ray sources have been detected. The 3-sigma upper limit at the BAT refined position (Markwardt et al. GCN Circ. 24020) is 1.95E-2 ct s^-1, corresponding to a 0.3-10 keV observed flux of 9.75E-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

The UVOT also does not detect any new source at the BAT refined position. 
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(ks)   T_stop(ks)      Exp(ks)         Mag

uvw1            1633          1640           1.89         >20.47

The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).

The BAT refined analysis pointed out that the unusually soft spectrum hinted at a possible SGR nature for the source.
However, a non detection at T+18.9 days is consistent with the expected behavior of a short GRB, and we conclude that it is more likely that the event was a Gamma Ray Burst.


This circular is an official product of the Swift XRT and UVOT teams.


GRB_name: GRB190406B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24130
SUBJECT: GRB 190406B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 576241792)
DATE:    19/04/18 22:06:52 GMT
FROM:    Tomas Ahumada at U. of Maryland  <tahumada@astro.umd.edu>

Authors: Tomas Ahumada (UMD), S. Bradley Cenko (NASA GSFC), Michael W.
Coughlin (Caltech), Eric C. Bellm (UW), Leo P. Singer (NASA GSFC), Shaon
Ghosh (UWM), Mansi M. Kasliwal (Caltech), Shreya Anand (Caltech), Igor
Andreoni (Caltech), Scott Adams (Caltech), Matt Hankins (Caltech), Varun
Bhalerao (IITB), Harsh Kumar (IITB), V. Zach Golkhou (UW) on behalf of the
ZTF and GROWTH collaborations and the KPED team

We observed the localization region of the short GRB190406B (trigger
576241792) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi
satellite with the Palomar 48 inch telescope equipped with the 47 square
degree Zwicky Transient Facility (ZTF) camera. We obtained a series of r-
and g-band images covering 268 square degrees beginning at 08:01 UT on 2019
April 08 (44:52 hours after the burst trigger time). This corresponds to ~
44% of the probability enclosed in the intersection of the GBM and IPN
localization regions. We revisited the region on 2019 April 11, starting at
08:03 UT (116:54 hours after the burst trigger time) and we covered the
same ~ 44% of the probability region.

The images were processed through the ZTF reduction and image subtraction
pipelines at IPAC to search for potential counterparts. 240
high-significance transient and variable candidates were identified by our
pipeline in the area observed, 236 of which had previous detections with
ZTF in the days and weeks prior to the GRB trigger time (e.g., supernovae,
active galactic nuclei).

Further follow-up of 4 transients was obtained with the Kitt Peak EMCCD
Demonstrator (KPED) on the Kitt Peak 84-inch telescope on April 12.
Additionally, we obtained follow-up spectroscopy of 2 candidates with the
Double Spectrograph (DBSP) on Palomar 200â€ the nights of April 12. The
candidates are listed below, however no photometric evolution or spectral
classification was consistent with an optical counterpart.

----------------------------------------------------------------------------------------------------------------------------

       ZTF ID            RA DEC         last non-detection discovery   KPED
Class

----------------------------------------------------------------------------------------------------------------------------


                                 deg deg date in 2019       April 08 April
12

----------------------------------------------------------------------------------------------------------------------------
ZTF19aapgbri    275.504094 +55.964483    04-07 r<20.41    g = 21.36
  g=20.76        SN Ia
ZTF19aapgdcn  285.158686 +69.881810     04-04 r<19.49    g = 20.67   g=21.74
       SN Ia

ZTF19aapfxqv     276.915046 +65.626121    04-04 r<17.61    g=20.67
  g=20.67    SN*

ZTF19aapwbgo   278.519641 +57.057325    04-07 r<20.35    g=21.61   g=22.36
   SN*

-------------------------------------------------------------------------------------------------------------------------

*Classification from photometric data points.


The median 5 sigma upper limit for an isolated point source in our images
was r > 21.5 and g > 21.8 mag for the observations made on April 8 26 and r
> 21.9 and g > 21.6 mag for the observations made on April 11.

ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266
<http://www.astronomerstelegram.org/?read=11266>), and includes IPAC; WIS,
Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; NRC, Taiwan; UW
Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the
NSF under AST MSIP Grant No 1440341. Alert distribution service provided by
DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system,
supported by NSF PIRE grant 1545949.


GRB_name: GRB190419A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24132
SUBJECT: Fermi Trigger 577360542 / GRB 190419414 / GRB190419A: BALROG localization
DATE:    19/04/19 10:40:39 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
577360542 at 09:55:37 on 19 April 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 112.4+/-5.1 deg
Decl.(2000.0) = -38.8+/-1.8 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190419414/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190419414/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190419414/json

                        


GRB_name: GRB190406B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24133
SUBJECT: Fermi trigger 576241792 / GRB 190406B: MASTER optical observation 
DATE:    19/04/19 17:30:29 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov,
A.Kuznetsov, P.Balanutsa, A. Chasovnikov, V.Topolev, D.Kuvshinov, F.Balakin (Lomonosov Moscow State University, SAI, Physics Department),

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

O. Gress, N.M. Budnev, O.Ershova (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),


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

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE SJNU)

MASTER Global Robotic Net (http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, v. 2010, 30L)
automatically started inspection of  Fermi trigger 576241792 https://gcn.gsfc.nasa.gov/other/576241792.fermi
7843s after trigger time at 2019-04-06  13:20:30 UT

MASTER Net cover map is available at http://observ.pereplet.ru/images/MASTER_FermiTrig576241792covermap.jpg

MASTER-Tunka robotic telescope located in Russia (Applied Physics Institute, Irkutsk State University)
was pointed to the  FERMI GRB190406.47 ( 19h  5m 21.60s , +61d 30m 00.00s, R=7.09)
7843 sec after trigger time at 2019-04-06 13:20:30 UT, with upper limit up to  19.8 mag.
Observations started at twilight.  The observations began at zenit distance = 65 deg. The sun  altitude  is -14.6 deg.

MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory)
started FERMI GRB190406.47 / trigger 576241792 inspection  20777 sec after trigger time at 2019-04-06 16:56:04 UT, 
with upper limit up to  19.9 mag. Observations started at twilight.
  The observations began at zenit distance = 74 deg. The sun  altitude  is -13.8 deg.

MASTER-Tavrida robotic telescope  located in Russia (Lomonosov MSU, SAI Crimea astronomical station)
started FERMI GRB190406.47 inspection 26157 sec after trigger time at 2019-04-06 18:25:44 UT, with upper limit up to  19.5 mag.
The observations began at zenit distance = 70 deg. The sun  altitude  is -22.5 deg.

MASTER-IAC robotic telescope  located in Spain (IAC Teide Observatory) started
  FERMI GRB190406.47 inspection 39426 sec after trigger time at 2019-04-06 22:06:53 UT, with upper limit up to  20.1 mag.
The observations began at zenit distance = 84 deg. The sun  altitude  is -34.8 deg.

The galactic latitude b = -60 deg., longitude l = 98 deg.


MASTER auto-detection system didn't find OT connected with GRB.

During inspection we find OT

MASTER OT J193011.47+465928.3 detection - preliminary dwarf nova outburst, ampl>4.3m

MASTER-Kislovodsk auto-detection system (Lipunov et al., 2010, Advances in Astronomy, v. 2010, 30L)
discovered OT source at (RA, Dec) = 19h 30m 11.47s +46d 59m 28.3s on 2019-04-07.95397 UT.
The OT unfiltered magnitude is 15.4m (limit 19.0m).

The OT is seen in 8 images. There is no minor planet at this place.

We have reference image without OT on 2019-02-13.08602 UT with unfiltered 
magnitude limit 19.6m, on 2016-07-29 21:12:44 with mlim=19.7, it means 
more then 4.3m of current outburst amplitude (there is USNO-B1 star in 0.3" with B1=19.5,R2=19.3).

Spectral observations are required.

The discovery and reference images are available at:
http://master.sai.msu.ru/static/OT/193011.47465928.3.png

We checked coordinates of 4 ZTF candidates (Ahumada et al. GCN24130) in 
MASTER database  and didn't find OT at position of 3 ones since 2009y (up to unfiltered 20.0)

About ZTF19aapfxqv
MASTER has seen an object at the position 
18h 27m 39.96s , +65d 37m 33.70s (MASTER OT J182739.96+653733.70) 
on 2017-12-07 21:15:28.334UT with m_OT=18.3+-0.2 (and we should note there 
is PanSTARRs source in 5.7").

This message may be cited


GRB_name: GRB190415A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24138
SUBJECT: Konus-Wind observation of GRB 190415A
DATE:    19/04/21 18:33:57 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long GRB 190415A (Insight-HXMT/HE detection: Luo et al.,
GCN 24125; IPN triangulation: Svinkin et al., GCN 24128)
triggered Konus-Wind (KW) at T0=14986.024 s UT (04:09:46.024).

The light curve of the burst shows a bright, hard-spectrum,
multi-peaked pulse, which started at ~T0 s and had a duration of ~ 19s. 
This pulse was followed by a weaker and softer emission tail
of the emission detectable until ~T0+57 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/GRB190415_T14986/

As observed by Konus-Wind, the burst had
a fluence of (8.8 Â± 0.8)x10^-5 erg/cm2 and
a 64-ms peak energy flux, measured from T0+5.824,
of (2.33 Â± 0.14)x10^-5 erg/cm2 (both in the 20 keV - 10 MeV
energy range).

The time-integrated spectrum (measured from T0 to T0+56.512 s)
is best fit in the 20 keV - 15 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.65(-0.10,+0.11),
and the peak energy Ep = 892(-99,+120) keV,
chi2 = 94/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta (-3.1).

The spectrum near the peak count rate (measured from T0 to T0+7.360)
is best fit in the 20 keV - 15 MeV range by
the CPL function with the following model parameters:
the photon index alpha = -0.17(-0.09,+0.10),
and the peak energy Ep = 994(-62,+67) keV,
chi2 = 89/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta (-3.8).

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB190422A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24147
SUBJECT: GRB 190422A: Swift detection of a burst
DATE:    19/04/22 23:15:41 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

M. J. Moss (George Washington University), S. D. Barthelmy (GSFC),
J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),
N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 22:55:29 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190422A (trigger=899979).  Swift did not slew until ~T+8 min 
due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 182.124, -60.238 which is 
   RA(J2000) = 12h 08m 30s
   Dec(J2000) = -60d 14' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of at least 220 sec, where data are currently
available. The peak count rate based on the available data
was ~2000 counts/sec (15-350 keV), at ~175 sec after the trigger. 

The XRT began observing the field at 23:04:18.5 UT, 529.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 182.03650, -60.22311 which is
equivalent to:
   RA(J2000)  = 12h 08m 08.76s
   Dec(J2000) = -60d 13' 23.2"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 165 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
http://www.swift.ac.uk/sper.  We cannot determine whether the source is
fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (8.59 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 1.1
(+1.25/-0.89) x 10^22 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 531 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 none of
the XRT error circle. 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 large, but
uncertain, extinction expected. 

This source lies within the current (Sector 11) field-of-view of TESS camera 2. 

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: GRB190422A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24151
SUBJECT: GRB 190422A: Enhanced Swift-XRT position
DATE:    19/04/23 02:43:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1699 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 190422A, 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 = 182.03450, -60.22425 which is equivalent
to:

RA (J2000): 12h 08m 8.28s
Dec (J2000): -60d 13' 27.3"

with an uncertainty of 1.8 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: GRB190422A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24155
SUBJECT: GRB 190422A: Swift-XRT refined Analysis
DATE:    19/04/23 14:32:12 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), A. Tohuvavohu (PSU), A.P. Beardmore (U. Leicester),
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), A. D'Ai
(INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), S. J.
LaPorte (PSU) and M.J. Moss report on behalf of the Swift-XRT team:

We have analysed 6.8 ks of XRT data for GRB 190422A (Moss et al. GCN
Circ. 24147), from 536 s to 31.0 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 24151).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.7 (+1.8, -1.2). At T+895 s  the decay
flattens to an alpha of -0.4 (+0.4, -0.5) before breaking again at
T+3926 s to a final decay with index alpha=0.54 (+/-0.15).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.04 (+0.18, -0.17). The
best-fitting absorption column is  1.66 (+0.25, -0.23) x 10^22 cm^-2,
in excess of the Galactic value of 8.6 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 5.5 x 10^-11 (1.2 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.66 (+0.25, -0.23) x 10^22 cm^-2
Galactic foreground: 8.6 x 10^21 cm^-2
Excess significance: 5.7 sigma
Photon index:      2.04 (+0.18, -0.17)

If the light curve continues to decay with a power-law decay index of
0.54, the count rate at T+24 hours will be 0.11 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.3 x
10^-12 (1.4 x 10^-11) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00899979.

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


GRB_name: GRB190422A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24157
SUBJECT: GRB 190422A: Swift-BAT refined analysis
DATE:    19/04/23 15:19:18 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
M. J. Moss (GWU), D. M. Palmer (LANL),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 190422A (trigger #899979)
(Moss et al., GCN Circ. 24147).  The BAT ground-calculated position is
RA, Dec = 182.126, -60.167 deg which is
   RA(J2000)  =  12h 08m 30.3s
   Dec(J2000) = -60d 10' 02.6"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 82%.

The mask-weighted light curve shows a multi-peaked structure. The emission
started before the source entered the BAT FOV, and lasted until ~T+360 s.
The main peak occurred at ~ T+175 s. We cannot determine T90 since
the available data do not cover the entire burst emission.

The time-averaged spectrum from T+6.39 to T+359.48 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.76 +- 0.08.  The fluence in the 15-150 keV band is 6.5 +- 0.3 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+174.47 sec in the 15-150 keV band
is 2.6 +- 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/899979/BA/


GRB_name: GRB190422A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24159
SUBJECT: GRB 190422A: Swift/UVOT Upper Limits
DATE:    19/04/23 17:30:19 GMT
FROM:    Kira Simpson at PSU  <kira.simpson1984@gmail.com>

GRB 190422A: Swift/UVOT Upper Limits

K. K. Simpson (PSU) and M. J. Moss (George Washington University)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190422A
532 s after the BAT trigger (Moss et al., GCN Circ. 24147).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 24151)
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           532          682          147         >18.8
white              532         7906          647         >18.8
v                  689         6879          352         >17.2
b                  788         7700          352         >18.3
u                  763         7495          352         >18.9
w1                 738         7289          352         >19.1
m2                 713         7084          352         >19.1
w2                 838         7995          438         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.58 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190422A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24161
SUBJECT: GRB 190422A: Fermi GBM detection
DATE:    19/04/23 22:20:03 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH), C. Fletcher (USRA), and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 22:58:24.00 UT on 22 April 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190422A (trigger 577666709 / 190422957)
which was also detected by the Swift/BAT (Moss et al. 2019, GCN 24147).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 71
degrees.

The GBM light curve shows a complex lightcurve with one main peak
preceded and followed by weaker bursts of emission.
A duration (T90) is calculated to be about 212 s (50-300 keV).
The time-averaged spectrum from T0-21.5 s to T0+42.0 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.67 +/- 0.09 and
the cutoff energy, parameterized as Epeak, is 58 +/- 7 keV.
A Band function fits the spectrum equally well with
Epeak = 50 +/- 9 keV, alpha = -1.57 +/- 0.14 and
beta = -2.42 +/- 0.27.

The event fluence (10-1000 keV) in this time interval is
(4.8 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.54 s in the 10-1000 keV band
is 4.84 +/- 0.17 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: GRB190424A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24163
SUBJECT: GRB 190424A: Swift detection of a burst
DATE:    19/04/24 10:13:57 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J.D. Gropp (PSU), N. J. Klingler (PSU), K. L. Page (U Leicester) and
D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 10:00:43 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190424A (trigger=900285).  Swift did not slew to the burst
due to an observing constraint.  The BAT on-board calculated location is 
RA, Dec 48.681, +20.233 which is 
   RA(J2000) = 03h 14m 43s
   Dec(J2000) = +20d 14' 00"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single FRED peak
structure with a duration of about 20 sec.  The peak count rate
was ~900 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 17:34 UT on 2019 June 30. There will thus be no XRT or
UVOT data for this trigger before this time. 

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: GRB190424A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24164
SUBJECT: GRB 190424A: Swift-BAT refined analysis
DATE:    19/04/24 21:26:50 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
J.D. Gropp (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU),
T. N. Ukwatta (LANL) (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 190424A (trigger #900285)
(Group, et al., GCN Circ. 24163).  The BAT ground-calculated position is
RA, Dec = 48.693, 20.239 deg which is
   RA(J2000)  =  03h 14m 46.2s
   Dec(J2000) = +20d 14' 19.9"
with an uncertainty of 1.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 41%.

The mask-weighted light curve shows a single, fairly symmetrical pulse
starting
at T-2 seconds, peaking at T+2 sec, and declining to background by T+12 sec.
The spacecraft slewed away from the burst location at T+80 sec.
T90 (15-350 keV) is 10.6 +- 2.3 sec (estimated error including systematics).

The time-averaged spectrum from T-1.31 to T+12.04 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.45 +- 0.13.  The fluence in the 15-150 keV band is 1.2 +- 0.1 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T+1.10 sec in the 15-150 keV band
is 2.0 +- 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/900285/BA/


GRB_name: GRB190427A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24261
SUBJECT: GRB 190427A: Swift detection of a short burst
DATE:    19/04/27 04:43:39 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. Tohuvavohu (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC),
D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 04:34:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190427A (trigger=900730).  Swift's slew will be delayed
due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 280.213, +40.322 which is 
   RA(J2000) = 18h 40m 51s
   Dec(J2000) = +40d 19' 20"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single short
structure with a duration of about 0.5 sec.  The peak count rate
was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+43.4
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is A. Tohuvavohu (aaronb AT swift.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: GRB190427A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24264
SUBJECT: GRB 190427A: Swift-XRT observations
DATE:    19/04/27 06:14:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. Campana (INAF-OAB), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU) and G. Tagliaferri
(INAF-OAB) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 190427A at 05:36:30.6 UT,
3735.8 seconds after the BAT trigger. No source was detected in 142 s
of promptly downlinked data. We are waiting for the full dataset to
detect and localise the XRT counterpart.


GRB_name: GRB190427A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24265
SUBJECT: GRB 190427A: NOT optical observations
DATE:    19/04/27 06:25:28 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

L. Izzo (HETH/IAA-CSIC), D. B. Malesani (DAWN/NBI and DARK/NBI), D. Xu 
(NAOC/CAS), and N. Jannsen (NOT), report:

We observed the field of the Swift GRB 190427A (Tohuvavohu et al., GCN 
24261; Campana et al., GCN 24264) using the Nordic Optical Telescope 
(NOT) located in La Palma (Canary Islands, Spain), equipped with the 
ALFOSC camera. We have obtained a series of 2 exposures of 300 s each in 
the SDSS râ€™, iâ€™ and zâ€™ filters.

The first r'-band image was acquired starting on 2019 Apr 27.19742 UT 
(602 s after the GRB). Visual comparison with the Pan-STARRS archival 
images reveals no new sources inside the BAT error circle, down to a 
limiting magnitude r = 23.5 AB (calibrated against Pan-STARRS sources).

Further analysis is ongoing.


GRB_name: GRB190427A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24272
SUBJECT: GRB 190427A: BOOTES-1 and BOOTES-5/JGT early follow-up observations
DATE:    19/04/27 08:22:34 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

Y.-D. Hu, X.-Y.Li, E. Fernandez-Garcia, A. Ayala, and A. J. 
Castro-Tirado (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), S. Jeong and 
I. H. Park (SKKU), I. Carrasco, A. Castellon, C. Perez del Pulgar (Univ. 
de Malaga), S. B. Pandey (ARIES) and M. D. Caballero-Garcia (ASU-CAS, 
CZ) on behalf of a larger collaboration, report:

Following the detection of the short-duration GRB 190427A (Tohuvavohu et 
al. GCNC 24261), both the 30cm BOOTES-1 robotic telescope in Mazagon 
(Huelva, southern Spain) and the BOOTES-5/JGT robotic telescope at 
Observatorio Astronomico Nacional in San Pedro Martir (Mexico), 
automatically responded at 04:35:01 UT (~46 s after trigger) and 
04:55:00 UT (~0.33 hr after trigger) respectively. No optical afterglow 
is detected down to 17 mag and 20 mag respectively. This is consistent 
with the no-detection reported by Lipunov et al. (GCNC 24263) and Izzo 
et al. (GCNC 24265). Further analysis is ongoing.


GRB_name: GRB190427A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24282
SUBJECT: GRB 190427A: RATIR Optical and NIR Observations
DATE:    19/04/27 14:08:29 GMT
FROM:    Eleonora Troja at NASA/GSFC/UMD  <eleonora@umd.edu>

Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),
Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),
Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos Roman-Zuniga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.),
and Vicki Toy (UMD) report:

We observed the field of GRB 190427A (Tohuvavohu, et al., GCN 24261)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
Astronomico Nacional on Sierra San Pedro Martir from 2019/04 27.28 to
2019/04 27.30 UTC (2.22 to 2.53 hours after the BAT trigger), obtaining
a total of 0.20 hours exposure in the r and i bands and 0.06 hours
exposure in the Z, Y, J, and H bands.

In comparison with the SDSS DR9 catalog, we detect no new source brighter
than r~22 AB mag within the BAT error circle.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro
Martir.


GRB_name: GRB190427A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24287
SUBJECT: GRB 190427A: COATLI Optical Observations 
DATE:    19/04/27 15:13:14 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Eleonora Troja (GSFC), Nat Butler (ASU), Rosa L.
Becerra (UNAM), Diego GonzÃ¡lez (UNAM), William H. Lee (UNAM), Margarita
Pereyra (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM) and Alexander Kutyrev (GSFC)
report:

We observed the field of GRB 190427A (Tohuvavohu et al., GCN Circ.
24261) with the COATLI 50-cm telescope and interim imager at the
Observatorio AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir
(http://coatli.astroscu.unam.mx) from 2019-02-04 05:28:30 to 06:36:27
(from 0.9 to 2.0 hours after the trigger), obtaining a total of 3000
seconds of exposure in the w filter.

Comparing to the USNO and Pan-STARRS1 catalogs, we do not detect any new
sources brighter than w = 21 in the BAT error region.

Our w magnitudes are calibrated against the Pan-STARRS1 catalog, are on 
an approximate AB system, and are not corrected for Galactic extinction
in the direction of the GRB.

We thank the COATLI technical team and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB190427A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24288
SUBJECT: GRB 190427A: MITSuME Akeno optical upper limits
DATE:    19/04/27 15:58:22 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. Niwano, R. Adachi, Y.
Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME
collaboration:

We searched for the optical counterpart of GRB 190427A (Tohuvavohu et al.,
GCN Circular #24261) with the optical three color (g', Rc, and Ic) CCD
cameras attached to the MITSuME 50 cm telescope of Akeno Observatory,
Yamanashi, Japan.
The observation started on 13:16:48 UT. We did not find any new point
sources within the BAT circle (Tohuvavohu et al., GCN Circular #24261) in
all three bands.
We obtained the following 5-sigma limits for the magnitudes.

T0+[hour]   MID-UT    T-EXP[sec]                           5-sigma limits
------------------------------------------------------------------------------------------------
 ~8.7         13:35:08   1620(g'),1560(Rc),1980(Ic)   g'>17.8,Rc>18.2,Ic
>18.6
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the AB system.


GRB_name: GRB190427A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24290
SUBJECT: GRB 190427A: Lick/Nickel telescope optical observations
DATE:    19/04/27 16:07:18 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

Keto Zhang, Shaunak Modak, WeiKang Zheng and Alexei V. Filippenko
(UC Berkeley) report on behalf of the KAIT GRB team:

We observed the field of GRB 190427A (Tohuvavohu et al., GCN 24261) with
the 1-m Nickel telescope located at Lick observatory, California.
Observations started about 4.31 hours after the burst. A total of
5 image in R band were taken with each exposure time of 600s.
No viable counterparts were identified in our images. The limiting
magnitude of our 5 combined image is R~22.0 mag calibrated to the
Pan-STARRS1 catalog.


GRB_name: GRB190427A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24293
SUBJECT: GRB 190427A: Fermi GBM detection
DATE:    19/04/27 17:14:36 GMT
FROM:    Christian Malacaria at NASA-MSFC/USRA  <cmalacaria@usra.edu>

C. Malacaria (NASA-MSFC/USRA), A. von Kienlin (MPE) 
and C. Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 04:34:15.08  UT on 27 04 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190427A (trigger 578032460 / 190427190).
The event was also detected by the Swift/BAT
(Tohuvavohu et al. 2019, GCN 24261)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time 
is 106 degrees.

The GBM light curve consists of a dominant pulse with following 
structure and a duration (T90) of about 0.37 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.384 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.05 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 246.40 +/- 78.20 keV.

The event fluence (10-1000 keV) in this time interval is
(4.855 +/- 0.717)E-07 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.0 s in the 10-1000 keV band
is 18.8 +/- 1.1 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: GRB190419A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24297
SUBJECT: GRB 190419A: AstroSat CZTI detection
DATE:    19/04/27 19:16:28 GMT
FROM:    Tanazza Khanam at IUCAA  <tanazza@iucaa.in>

T. Khanam, V. Sharma, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a GRB 190419A, which was also detected by FERMI (Kunzweiler F. et al, GCN #24132) and Global-MASTER Net (Lipunov V. et al, GCN #24135).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 09:55:42.5 UT. The measured peak count rate associated with the burst is 134.65 cts/s above the background in the combined data of four quadrants, with a total of 690 cts. The local mean background count rate was 488.3 cts/s. Using cumulative rates, we measure a T90 of 7.7 s.

It was more clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190427A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24330
SUBJECT: GRB 190427A, Swift-BAT refined analysis
DATE:    19/04/28 15:40:56 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), A. Tohuvavohu (PSU)
(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 190427A (trigger #900730)
(Tohuvavohu et al., GCN Circ. 24261).  The BAT ground-calculated position is
RA, Dec = 280.217, 40.304 deg which is
   RA(J2000)  =  18h 40m 52.0s
   Dec(J2000) = +40d 18' 15.6"
with an uncertainty of 2.4 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 68%.

The mask-weighted light curve shows a double-peaked structure that starts
from ~ T0 and ends at ~T+0.3. The main peak occurs at ~T0, followed by a
weaker peak at ~T+0.2 s. T90 (15-350 keV) is 0.3 +- 0.1 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.0 to T+0.3 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.17 +- 0.21.  The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T-0.33 sec in the 15-150 keV band
is 1.6 +- 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/900730/BA/


GRB_name: GRB190428A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24332
SUBJECT: Fermi Trigger 578170097 / GRB 190428783 / GRB190428A: BALROG localization
DATE:    19/04/28 19:29:10 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
578170097 at 18:48:12 on 28 April 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 34.5+/-2.8 deg
Decl.(2000.0) = 19.4+/-2.1 deg
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190428783/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190428783/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190428783/json

                        


GRB_name: GRB190427A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24333
SUBJECT: GRB 190427A: Swift/UVOT Upper Limits
DATE:    19/04/28 20:09:21 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and A. Tohuvavohu (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 190427A
3737 s after the BAT trigger (Tohuvavohu et al., GCN Circ. 24261).
No optical afterglow consistent with the BAT position (Ukwatta et al.,
GCN Circ. 24330) 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                 3737         3936          197         >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190427A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24339
SUBJECT: GRB 190427A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/04/29 07:47:46 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

N. Cannady (LSU),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
T. Tamura, Y. Shimizu (Kanagawa U), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The short GRB 190427A (Swift-BAT trigger #900730:
Tohuvavohu et al., GCN Circ. 24261, Ukwatta et al., GCN Circ. 24330;
Fermi GBM detection: Malacaria, von Kienlin and Meegan, GCN Circ. 24293)
was detected in ground analysis of the CALET Gamma-ray Burst Monitor (CGBM)
data near the Swift-BAT trigger time at T0=04:34:14.95 UT on 27 April 2019.
The burst signal was seen only by the SGM detector.
The source location (Ukwatta et al., GCN Circ. 24330) was out
of the HXM detectors' FOVs and likely blocked by the ISS structures.

The burst light curve shows a single bin (125 ms) spike
with a signal-to-noise ratio of 9.0 in the 40-1000 keV range.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1240374828/

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


GRB_name: GRB190429A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24352
SUBJECT: GRB 190429A: AstroSat CZTI detection
DATE:    19/04/30 12:55:55 GMT
FROM:    Tanazza Khanam at IUCAA  <tanazza@iucaa.in>

T. Khanam, V. Sharma, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

GRB 190429A, reported by Global-MASTER Net (Lipunov V. et al, GCN #24347), registered a weak detection in the CsI anticoincidence (Veto) detector of the AstroSat CZT Imager at 17:49:51.0 UTC.  No significant counts were found in the main CZT detectors.  

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190501A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24360
SUBJECT: GRB 190501A: AGILE/MCAL and scientific ratemeters detection of a burst
DATE:    19/05/01 10:32:09 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

A. Ursi (INAF/IAPS), F. Verrecchia, F. Lucarelli (SSDC, and INAF/OAR), N.
Parmiggiani (INAF/OAS-Bologna), C. Pittori (SSDC, and INAF/OAR), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C.
Casentini, Y. Evangelista, G. Piano (INAF/IAPS), A. Bulgarelli, V.
Fioretti, F. Fuschino, (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna,
and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I.
Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani
(INAF/IASF-Mi), report on behalf of the AGILE Team:

AGILE detected a long burst at T0 = 2019-05-01 05:23:23.58 +/- 0.01 s (UTC).

The event is visible in the scientific ratemeters (RMs) of the Super-AGILE
(SA, 18-60 keV), Anti-Coincidence (AC, 50-200 keV), and Mini-Calorimeter
(MCAL, 0.4-100 MeV) detectors. Their light curves show a multi-peaked FRED
profile, lasting ~24 s and releasing ~11200 counts in the SA RMs, lasting
~15 s and releasing ~2000 counts in the AC RMs, and lasting ~18 s and
releasing ~20200 counts in the MCAL RMs. The ratemeters light curves can be
found at
http://www.agilescienceapp.it/notices/GRB_062362_483773003.584545_RM.png.

The event also triggered a Mini-Calorimeter (MCAL) data acquisition lasting
~8.6 s and releasing a total number of ~10140 counts in the detector (in
the 0.4-100 MeV energy range). The MCAL light curve can be found at:
http://www.agilescienceapp.it/notices/GRB_062362_483773003.584545.png.

Further analysis of the Gamma-Ray Imaging Detector (GRID) data is still in
progress.

The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the
energy range 0.4-100 MeV. Additional analysis of AGILE data is in progress.


GRB_name: GRB190501A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24361
SUBJECT: GRB 190501A: AGILE/GRID detection
DATE:    19/05/01 12:17:54 GMT
FROM:    Fabrizio Lucarelli at SSDC/INAF-OAR  <fabrizio.lucarelli@ssdc.asi.it>

F. Lucarelli, F. Verrecchia (SSDC, and INAF/OAR), G. Piano (INAF/IAPS), M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, Y. Evangelista, A. Ursi
(INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino
(INAF/OAS), M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), I. Donnarumma (ASI),
A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team:

The Gamma-Ray Imaging Detector (GRID) of AGILE detected a gamma-ray transient
temporally coincident with the long bright GRB 190501A reported by Ursi et al.,
GCN #24360. Given the rarity of this transient, we consider it the gamma-ray
counterpart of GRB 190501A.

A preliminary GRID analysis in the energy range 30 MeV - 1 GeV shows a
detection with a statistical significance of about 18 sigma, at the
sky position R.A., Decl. (J2000): 174,+65 +/- 5 deg (Galactic coordinates l,b:
135,+50 deg), over a time integration of 20 s starting from the T0 of GRB 190501A.

The preliminary estimated position is below the GRID 30 deg off-axis angle.

These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.


GRB_name: GRB190501A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24363
SUBJECT: GRB 190501A: refined position from AGILE/GRID analysis
DATE:    19/05/01 17:32:13 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia@ssdc.asi.it>

F. Verrecchia, F. Lucarelli (SSDC, and INAF/OAR), G. Piano (INAF/IAPS), M.
Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), A. Giuliani (INAF/IASF-Mi), M.
Cardillo,
C. Casentini, A. Ursi (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR), Y.
Evangelista
(INAF/IAPS), A. Bulgarelli, V. Fioretti, N. Parmiggiani, F. Fuschino
(INAF/OAS),
M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), I.
Donnarumma
(ASI), report on behalf of the AGILE Team:

We refined the position of the long GRB 190501A detected by the Gamma-Ray
Imaging Detector (GRID) of AGILE (Lucarelli et al., GCN #24361) and
previously
reported by Ursi et al., GCN #24360.
A preliminary maximum likelihood analysis integrating from T0 to T0+500 s
yields a detection at 7 sigma with an average flux of F(E> 30
MeV)=(50+/-15)e-05
ph/cm^2/s, with the positional error box centered at R.A., Dec. (J2000) =
172.8, 64.1 deg with a mean radius of 0.8 deg (95% stat. c.l.) [ Galactic
coordinates (l,b)=(136.6, 50.8) deg ].

This is among the most intense gamma-ray flux ever detected by AGILE
from a GRB.

These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.


GRB_name: GRB190502A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24365
SUBJECT: Fermi Trigger 578462495 / GRB 190502168 / GRB190502A: BALROG localization
DATE:    19/05/02 05:54:59 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
578462495 at 04:01:30 on 02 May 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 94.0+/-2.9 deg
Decl.(2000.0) = 12.4+/-2.4 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190502168/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190502168/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190502168/json

                        


GRB_name: GRB190501A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24370
SUBJECT: GRB 190501A: GOTO optical counterpart search
DATE:    19/05/02 16:52:17 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>

J.Lyman(1), K.Ulaczyk(1), K.Wiersema(1), D.Steeghs(1),
M.Dyer(3), D.Galloway(2), V.Dhillon(3), P.O'Brien(4),
G.Ramsay(5), D.Pollacco(1), E.Thrane(2), S.Poshyachinda(6),
E.Palle(7),  R.Cutter(1), A.Levan(1), T. Marsh(1), R.West(1),
B.Gompertz(1), E.Stanway(1), K.Ackley(2), A.Obradovic(2),
Y-L.Mong(2), A.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3),
S.Littlefair(3), L.Makrygianni(3), E.Daw(3), J.Maund(3),
R.Starling(4), R.Eyles(4), S.Tooke(4), U.Sawangwit(6),
D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6),
P.Irawati(6), M.Kennedy(8), R.Breton(8), D.Mata-Sanchez(8),
 T.Heikkila(9), R.Kotak(9)
(1) Warwick University; (2) Monash University; (3) Univ. of Sheffield;
(4) University of Leicester; (5) Armagh Observatory & Planetarium;
(6) National Astronomical Research Institute of Thailand;
(7) Instituto de Astrofisica de Canarias; (8) Univ. of Manchester;
(9) University of Turku

report on behalf of the GOTO collaboration:

We report on optical observations with the Gravitational-wave Optical
Transient Observer in response to the AGILE detected GRB 190501A (Ursi
et al. GCN #24360).

The refined position reported in Verrecchia et al. (GCN #24363) was
covered with a set of 5x90s exposures starting at 2019-05-01T20:49
(15.4 hours after the burst) using our wide L filter (400-700 nm).

No viable counterpart is detected using a difference imaging
analysis based on recent survey observations of the same pointing. We
achieved a 5-sigma detection limit of g=20, based on a photometric
calibration against PS1 stars.


GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC) (https://goto-observatory.org/)


GRB_name: GRB190501A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24371
SUBJECT: GRB 190501A: Swift ToO observations
DATE:    19/05/02 22:13:18 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a ToO observation of the AGILE GRB 190501A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020892

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 AGILE 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: GRB190501A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24372
SUBJECT: IPN Triangulation of GRB 190501A (long/bright)
DATE:    19/05/03 00:02:49 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

A. Ursi, N. Parmiggiani, F. Verrecchia, A. Bulgarelli,
A. Trois, M. Marisaldi, C. Pittori, M. Tavani, Y. Evangelista,
I. Donnarumma, M. Cardillo, G. Piano, G. Minervini, A. Argan,
F. Lucarelli, A. Zoli, V. Fioretti, F. Fuschino, M. Pilia,
F. Longo, A. Giuliani on behalf of the AGILE team, and

W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr,
on behalf of the GRS-Odyssey GRB team, report:

The long-duration, very bright GRB 190501A
(AGILE-MCAL detection: Ursi et al., GCN Circ. 24360;
AGILE-GRID detection: Lucarelli et al., GCN Circ. 24361;
AGILE-GRID refined position: Verrecchia et al., GCN Circ. 24363)
was detected by AGILE (MCAL, GRID), INTEGRAL (SPI-ACS), Konus-Wind,
Mars-Odyssey (HEND), and CALET (GBM), at about 19395 s UT (05:23:15).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   173.591 (11h 34m 22s) +62.105 (+62d 06' 18")
  Corners:
   173.345 (11h 33m 23s) +61.440 (+61d 26' 24")
   174.192 (11h 36m 46s) +62.859 (+62d 51' 32")
   173.840 (11h 35m 22s) +62.766 (+62d 45' 57")
   173.007 (11h 32m 02s) +61.342 (+61d 20' 32")
  ---------------------------------------------
The error box area is about 691 sq. arcmin, and its maximum
dimension is 1.615 deg (the minimum one is 7.8 arcmin).
The Sun distance was about 95 deg.

This box may be improved.

The AGILE (GRID) refined position (RA, Dec, Rerr = 172.8, 64.1, 0.8 deg)
reported in Verrecchia et al. is inconsistent with the box, the
minimum distance between the box and the center of the AGILE (GRID) 
location is ~1.39 deg.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190501_T19401/IPN

The Konus-Wind time history and spectrum will be given in a forthcoming 
GCN Circular.


GRB_name: GRB190501B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24373
SUBJECT: GRB 190501B: AstroSat CZTI detection
DATE:    19/05/03 06:42:08 GMT
FROM:    Prachee Ghumatkar at IUCAA/AstroSat  <prachee@iucaa.in>

P. Ghumatkar, T. Khanam, V. Sharma, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a GRB 190501B.

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 02:11:50.5 UT. The measured peak count rate associated with the burst is 88 cts/s above the background in the combined data of four quadrants, with a total of 410 cts. The local mean background count rate was 408 cts/s. Using cumulative rates, we measure a T90 of  12.5s.

It was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.

[GCN OPS NOTE(23may19): See Circ 24374 that corrects the name in the Subject line from "BA" to "B".]


GRB_name: GRB190501B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24374
SUBJECT: Correction in name: GRB 190501B (not GRB 190501BA) : AstroSat CZTI detection
DATE:    19/05/03 07:44:13 GMT
FROM:    Prachee Ghumatkar at IUCAA/AstroSat  <prachee@iucaa.in>

P. Ghumatkar (IUCAA) report on behalf of the AstroSat CZTI team:

The GRB name of GRB 190501BA (P. Ghumatkar et al. GCN Circ. #24373) should be GRB 190501B.
I sincerely apologize for any confusion caused.


GRB_name: GRB190504A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24393
SUBJECT: IPN triangulation of GRB 190504A (short)
DATE:    19/05/05 01:20:57 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin and K. Hurley, on behalf of the IPN,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:

The short-duration GRB 190504A has been detected
by Fermi (GBM trigger 578679393) and INTEGRAL (SPI-ACS), so far,
at about 58588 s UT (16:16:28).

We have triangulated this GRB to a GBM-INTEGRAL annulus centered at
RA(2000)=282.762 deg (18h 51m 03s) Dec(2000)=+33.543 deg (+33d 32' 34"),
whose radius is 87.799 +/- 10.241 deg (3 sigma).

The annulus is inconsistent with the high-energy neutrino candidate
event IceCube-190503A (IceCube Collaboration GCN Circ. 24378).

This annulus may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190504_T58588/IPN/


GRB_name: GRB190501A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24406
SUBJECT: GRB 190501A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/05/06 11:11:48 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

S. Ricciarini (U of Florence),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
T. Tamura, Y. Shimizu (Kanagawa U), N. Cannady, M. L. Cherry (LSU),
P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long bright GRB 190501A (AGILE/MCAL detection: Ursi et al.,
GCN Circ. 24360; AGILE/GRID detection and localization: Lucarelli et al.,
GCN Circ. 24361, Verrecchia et al. GCN Circ. 24363;
IPN triangulation: Hurley et al., GCN Circ. 24372)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 05:23:17.604 UTC
on 1 May 2019. The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure which starts at
T=1.9 sec, peaks at 6.0 sec and ends at T+27.4 sec.
The T90 and T50 durations measured by the SGM data are 15.5 +- 3.5 sec
and 6.8 +- 0.6 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1240723364/

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


GRB_name: GRB190507A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24413
SUBJECT: GRB 190507A: Fermi GBM Final Real-time Localization
DATE:    19/05/07 06:39:47 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 06:28:23 UT on 7 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190507A (trigger 578903308.30089 / 190507270).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 156.0, Dec = -12.8 (J2000 degrees, equivalent to J2000 10h 23m, 12d -48'), with a statistical uncertainty of 4.8 degrees.

The angle from the Fermi LAT boresight is 72.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190507270/quicklook/glg_skymap_all_bn190507270.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190507270/quicklook/glg_healpix_all_bn190507270.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190507270/quicklook/glg_lc_medres34_bn190507270.gif


GRB_name: GRB190507A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24414
SUBJECT: Fermi Trigger 578903308 / GRB 190507270 / GRB190507A: BALROG localization
DATE:    19/05/07 07:33:13 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
578903308 at 06:28:23 on 07 May 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 158.4+/-3.5 deg
Decl.(2000.0) = -10.2+/-3.1 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190507270/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190507270/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190507270/json

                        


GRB_name: GRB190501A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24419
SUBJECT: GRB 190501A: Swift XRT and UVOT Observations
DATE:    19/05/07 13:10:39 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

Phil Evans (U. Leicester) and F.E. Marshall (NASA/GSFC)
report on behalf of the Swift team:

Swift-XRT has performed follow-up observations of the AGILE-detected
burst GRB 190501A (Ursi et al. GCN Circ. 24360), collecting 2.9 ks of
Photon Counting (PC) mode data between T0+146.7 ks and T0+157.7 ks.
The XRT field-of-view covers about 7% of the AGILE/GRID
95%-confidence error region (Verrecchia et al. GCN Circ. 24363) and none of
the IPN 3-sigma error region (Hurley et al. GCN Circ. 24732).

No uncatalogued X-ray sources have been detected. The 3-sigma upper
limit in the field ranges from ~0.003 to ~0.004 ct s^-1, corresponding
to a 0.3-10 keV observed flux of 1.2e-13 to 1.7e-13 erg cm^-2 s^-1
(assuming a typical GRB spectrum).

Three previously-catalogued X-ray sources have been detected, however
their status as catalogued objects makes them unlikely to be the
afterglow.

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020892.

The Swift/UVOT began settled observations of the field of GRB 190501A
146672 s after the AGILE trigger.
No optical afterglow consistent with the AGILE/GRID position
is detected in the initial UVOT exposures.
The UVOT images cover about 4% of the 95%-confidence
AGILE/GRID error region and none of the IPN 3-sigma error region.
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           147234       153893          933         >21.8
v               147796       154103          761         >20.0
u               146672       157636         1167         >20.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).

This circular is an official product of the Swift team.


GRB_name: GRB190507B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24422
SUBJECT: GRB 190507B: Fermi GBM Final Real-time Localization
DATE:    19/05/07 23:28:23 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 23:16:29 UT on 7 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190507B (trigger 578963794.637806 / 190507970).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 287.8, Dec = -22.8 (J2000 degrees, equivalent to J2000 19h 11m, 22d -49'), with a statistical uncertainty of 1.2 degrees.

The angle from the Fermi LAT boresight is 75.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190507970/quicklook/glg_skymap_all_bn190507970.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190507970/quicklook/glg_healpix_all_bn190507970.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190507970/quicklook/glg_lc_medres34_bn190507970.gif


GRB_name: GRB190507B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24425
SUBJECT: GRB 190507B: GOTO optical counterpart search
DATE:    19/05/08 11:45:34 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>

Y-L.Mong(1), K.Ackley(1), M.Kennedy(2), A.Obradovic(1), D.K.Galloway(1),
D.Steeghs(3), J.Lyman(3), K.Ulaczyk(3), K.Wiersema(3), M.Dyer(4),
V.Dhillon(4),
P.O'Brien(5), G.Ramsay(6), D.Pollacco(3), E.Thrane(1), S.Poshyachinda(7),
E.Palle(8), R.Cutter(3), A.Levan(3), T. Marsh(3), R.West(3), ,
B.Gompertz(3),
E.Stanway(3),  A.Casey(1), M.Brown(1), E.Rol(1), J.Mullaney(4),
S.Littlefair(4),
L.Makrygianni(4), E.Daw(4), J.Maund(4), R.Starling(5), R.Eyles(5),
S.Tooke(5),
U.Sawangwit(7), D.Mkrtichian(7), S.Awiphan(7), S.Aukkaravittayapun(7),
P.Irawati(7),
R.Breton(2), D.Mata-Sanchez(2), T.Heikkila(9), R.Kotak(9)
(1) Monash University; (2) Univ. of Manchester; (3) Warwick University;
(4) Univ. of Sheffield; (5) University of Leicester; (6) Armagh Observatory;
(7) National Astronomical Research Institute of Thailand;
(8) Instituto de Astrofisica de Canarias; (9) University of Turku

report on behalf of the GOTO collaboration:

We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO), in response to the Fermi trigger 578963794
(GRB190507.97, on 2019 May 7 23:16:29.64 UT, GCN #24422).

We made a series of 60s observations using our wide L-band filter
(400-700 nm), beginning on 2019 May 8 02:55 UT. We observed five
pointings covering 81.9% of the estimated sky uncertainty region of
3.9 degrees radius (68% confidence based on skymap linked in GCN
#24422).

We found no credible counterparts to the GRB detection, down to a
typical (5-sigma) limit of 19.7 mag.

We identify a single transient candidate, GOTO2019ayff, at
19:14:03.21, -23:12:37.88 detected at 17.66+/-0.03 mag (L) on 2019
May 8, 03:10 UT. The transient was subsequently found in a previous
image of the field on 2019 May 2 04:17:29 UT, pre-dating the Fermi
trigger, and is thus unrelated to the GRB. The estimated magnitude
(based on PS1 g-band calibrators) is roughly consistent with the
C-band limit reported for the Fermi trigger field by the MASTER
network (GCN #24423).

No object is known in Gaia DR2, Pan-STARRS, APASS, 2MASS, SIMBAD, or
TNS within 2.5" of this position. The source is close to (3.5"), but
clearly distinct from, a g=17.7 star in Pan-STARRS DR2 and was not
present in our reference epoch taken on 2019 April 13. The transient
may be associated with the nearby (20") galaxy 2MASX
J19140330-2312186.

GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC) (https://goto-observatory.org)


GRB_name: GRB190508A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24427
SUBJECT: GRB 190508A: Fermi GBM Final Real-time Localization
DATE:    19/05/08 19:34:46 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 19:22:50 UT on 8 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190508A (trigger 579036175.400484 / 190508808).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 178.0, Dec = 23.5 (J2000 degrees, equivalent to J2000 11h 51m, 23d 31'), with a statistical uncertainty of 2.1 degrees.

The angle from the Fermi LAT boresight is 98.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190508808/quicklook/glg_skymap_all_bn190508808.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190508808/quicklook/glg_healpix_all_bn190508808.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190508808/quicklook/glg_lc_medres34_bn190508808.gif


GRB_name: GRB190508B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24429
SUBJECT: GRB 190508B: Fermi GBM Final Real-time Localization
DATE:    19/05/08 23:52:27 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 23:41:24 UT on 8 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190508B (trigger 579051689.148352 / 190508987).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 103.5, Dec = 27.0 (J2000 degrees, equivalent to J2000 06h 54m, 27d 00'), with a statistical uncertainty of 11.0 degrees.

The angle from the Fermi LAT boresight is 52.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190508987/quicklook/glg_skymap_all_bn190508987.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190508987/quicklook/glg_healpix_all_bn190508987.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190508987/quicklook/glg_lc_medres34_bn190508987.gif


GRB_name: GRB190508A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24432
SUBJECT: GRB 190508A: GOTO optical search - no counterparts
DATE:    19/05/09 13:44:33 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <dsteeghs@gmail.com>

K.Ulaczyk(1), J.Lyman(1), D.Steeghs(1), D.Galloway(2)
K.Ackley(2), A.Obradovic(2), Y-L.Mong(2),
M.Dyer(3), V.Dhillon(3), P.O'Brien(4), G.Ramsay(5),
D.Pollacco(1), E.Thrane(2), S.Poshyachinda(6),
E.Palle(7), K.Wiersema(1), R.Cutter(1), A.Levan(1),
T. Marsh(1), R.West(1), B.Gompertz(1), E.Stanway(1),
A.Casey(2), M.Brown(2), E.Rol(2), J.Mullaney(3),
S.Littlefair(3), L.Makrygianni(3), E.Daw(3), J.Maund(3),
R.Starling(4), R.Eyles(4), S.Tooke(4), U.Sawangwit(6),
D.Mkrtichian(6), S.Awiphan(6), S.Aukkaravittayapun(6),
P.Irawati(6), M.Kennedy(8), R.Breton(8), D.Mata-Sanchez(8),
T.Heikkila(9), R.Kotak(9)
(1) Warwick University; (2) Monash University; (3) Univ. of Sheffield;
(4) University of Leicester; (5) Armagh Observatory & Planetarium;
(6) National Astronomical Research Institute of Thailand;
(7) Instituto de Astrofisica de Canarias; (8) Univ. of Manchester;
(9) University of Turku

report on behalf of the GOTO collaboration:

We carried out observations with the Gravitational-wave Optical
Transient Observer (GOTO), in response to the Fermi trigger 579036175
(GRB 190508A; GCN #24427).

We made a series of 3 x 60 s exposures using our wide L-band filter
(400-700 nm) with five pointings covering 75.9% of the estimated sky
probability region. Two independent sky passes started on 2019 May 8
21:04 UT (1.68 hrs post-burst) and 2019 May 9 1:12 UT.

Using a difference imaging analysis with recent survey observations
of the same pointings as reference, we identify no viable
counterparts. Our mean 5-sigma detection limit was g=20.6 mag based
on PS1 catalogue calibrators.


GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC) (https://goto-observatory.org)


GRB_name: GRB190510A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24449
SUBJECT: GRB 190510A: Fermi GBM Final Real-time Localization
DATE:    19/05/10 10:30:21 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 SHORT GRB

At 10:19:16 UT on 10 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190510A (trigger 579176361.043888 / 190510430).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 128.1, Dec = 33.5 (J2000 degrees, equivalent to J2000 08h 32m, 33d 30'), with a statistical uncertainty of 3.5 degrees.

The angle from the Fermi LAT boresight is 48.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190510430/quicklook/glg_skymap_all_bn190510430.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190510430/quicklook/glg_healpix_all_bn190510430.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190510430/quicklook/glg_lc_medres34_bn190510430.gif


GRB_name: GRB190501A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24452
SUBJECT: Konus-Wind observation of GRB 190501A
DATE:    19/05/10 12:50:16 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration, bright GRB 190501A
(AGILE/MCAL and scientific ratemeters detection:
Ursi  et al., GCN 24360;
AGILE/GRID detection: Lucarelli et al., GCN 24361;
Verrecchia et al., GCN 24363;
IPN Triangulation: Hurley et al., GCN 24372;
CALET Gamma-Ray Burst Monitor detection: Ricciarini t al., GCN 24406)
triggered Konus-Wind at T0=19401.146 s UT (05:23:21.146).

The burst light curve shows a bright, multi-peaked pulse with a duration 
of ~50 s
followed by a weak tail up to 137 s.
The emission is seen up  to ~1200 keV,  no KW data above 1.2 MeV are
available at the time of writing.

As observed by Konus-Wind, the burst
had a fluence of 2.04(-0.13,+0.13)x10^-4 erg/cm2,
and a 64-ms peak energy flux, measured from T0+4.272 s,
of 3.55(-0.99,+0.99)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+22.784 s)
is best fit in the 20 keV - 1.2 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.91(-0.04,+0.04),
the high energy photon index beta = -2.10(-0.09,+0.08),
the peak energy Ep = 316(-23,+24) keV,
chi2 = 70/59 dof.

The spectrum near the peak count rate
(measured from T0+3.840 to T0+4.352 s)
is best fit in the 20 keV - 1.2 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.65(-0.11,+0.14),
the high energy photon index beta = -2.28(-1.52,+0.31),
the peak energy Ep = 410(-72,+77) keV,
chi2 = 53/47 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190501_T19401/

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


GRB_name: GRB190511A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24471
SUBJECT: GRB 190511A: Fermi GBM Final Real-time Localization
DATE:    19/05/11 07:25:58 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 07:14:24 UT on 11 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190511A (trigger 579251669.35821 / 190511302).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 123.8, Dec = -24.3 (J2000 degrees, equivalent to J2000 08h 15m, -24d 18'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 19.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190511302/quicklook/glg_skymap_all_bn190511302.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190511302/quicklook/glg_healpix_all_bn190511302.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190511302/quicklook/glg_lc_medres34_bn190511302.gif


GRB_name: GRB190511A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24472
SUBJECT: GRB 190511A: Swift detection of a burst
DATE:    19/05/11 07:42:00 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

M. G. Bernardini (INAF-OAB), H. A. Krimm (NSF/USRA),
N. P. M. Kuin (UCL-MSSL), K. L. Page (U Leicester),
B. Sbarufatti (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 07:14:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190511A (trigger=903158).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 126.436, -20.242 which is 
   RA(J2000) = 08h 25m 45s
   Dec(J2000) = -20d 14' 30"
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 07:16:51.2 UT, 122.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 126.44482, -20.25978 which
is equivalent to:
   RA(J2000)  = 08h 25m 46.76s
   Dec(J2000) = -20d 15' 35.2"
with an uncertainty of 3.9 arcseconds (radius, 90% containment). This
location is 70 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 http://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. 

The initial flux in the 2.5 s image was 9.43e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of  95 seconds with the U filter starting
290 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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.09. 

Burst Advocate for this burst is M. G. Bernardini (grazia.bernardini AT brera.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: GRB190511A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24481
SUBJECT: GRB 190511A: Enhanced Swift-XRT position
DATE:    19/05/11 12:08:39 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 411 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 190511A, 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 = 126.44426, -20.25935 which is equivalent
to:

RA (J2000): 08h 25m 46.62s
Dec (J2000): -20d 15' 33.7"

with an uncertainty of 2.0 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: GRB190511A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24482
SUBJECT: GRB 190511A: Fermi GBM observation
DATE:    19/05/11 12:43:21 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:

"At 07:14:24.36 UT on 11 May 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190511A (trigger 579251669 / 190511302), 
which was also detected by the Swift/BAT (Bernardiniet al. 2019, GCN 24472)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 23.7 degrees.

This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of a multipeaked emission episode with 
a duration (T90) of about 28 s (50-300 keV).
The time-averaged spectrum from T0-2.048 s to T0+31.745 s is
best fit by a Band function with Epeak = 147.8 +/- 7.2 keV,
alpha = -0.58 +/- 0.05, and beta = -2.4 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(2.21 +/- 0.05)E-05 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+24.1924 s in the 10-1000 keV band
is 14.2 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB190511A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24483
SUBJECT: GRB 190511A: Fermi-LAT detection
DATE:    19/05/11 13:15:11 GMT
FROM:    Magnus Axelsson at Stockholm U.  <magaxe@kth.se>

M. Axelsson (KTH and Stockholm Univ.), F. Longo (Univ. and INFN Trieste), M. Arimoto (Kanazawa Univ.) and F. Dirirsa (Univ. of Johannesburg) report on behalf of the Fermi-LAT team:

On May 11, 2019, Fermi-LAT detected high-energy emission from GRB 190511A, which was also detected by Fermi-GBM (trigger 579251669 / 190511302; GCN 24482) and Swift (GCNs 24472 and 24481).

The best LAT on-ground location is found to be

RA, Dec 126.36, -20.25 (degrees, J2000)

with an error radius of 0.2 deg (90% containment, statistical error only).
This was 24 deg from the LAT boresight at the time of the GBM trigger:

T0 =  07:14:24.36 UT.

The data from the Fermi-LAT show a significant increase in the event rate after the GBM trigger that is spatially correlated with the GBM emission with high significance and consistent with the Swift location.

The photon flux above 100 MeV in the time interval 0-1400s after the GBM trigger is 3.6e-6 ph/cm2/s.

The estimated photon index above 100 MeV is -2.0 +/- 0.2.

The Fermi-LAT point of contact for this burst is Feraol Dirirsa (fdirirsa@uj.ac.za<mailto:fdirirsa@uj.ac.za>).

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: GRB190511A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24492
SUBJECT: GRB 190511A: NOT optical afterglow
DATE:    19/05/11 22:13:23 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Daniele B. Malesani (DAWN/NBI and DARK/NBI), Dong Xu (NAOC/CAS), Joonas 
Viuho (NOT and DAWN/NBI) report on behalf of a larger collaboration:

We observed the field of the Swift and Fermi GRB 190511A (Bernardini et 
al., GCN 24472; von Kienlin, GCN 24482; Axelsson et al., GCN 24483) 
using the Nordic Optical Telescope (NOT) equipped with the AlFOSC 
camera. Observations started in twilight and were carried out at high 
airmass due to the poor target visibility.

Just outside the enhanced XRT error position (Goad et al., GCN 24481), 
we clearly detect a source not visible in the archival Pan-STARRS images 
of the same area, which we suggest to be the optical afterglow of GRB 
190511A. Its coordinates are (J2000):

RA = 08:25:46.46
Dec = -20:15:33.4

Using nearby stars from the Pan-STARRS survey as calibrators, we measure 
for the afterglow a magnitude r = 20.89 +- 0.09 AB, at a mean epoch May 
11.8648 UT (13.51 hr after the trigger).


GRB_name: GRB190511A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24494
SUBJECT: GRB 190511A: Swift/UVOT Detection
DATE:    19/05/11 23:50:25 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL), M. de Pasquale (U. of Istanbul) and
M. G. Bernardini (INAF-OAB) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190511A
131 s after the BAT trigger (Bernardini et al., GCN Circ. 24472).
A source consistent with the XRT position
(Goad et al. GCN Circ. 24481)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  08:25:46.44 = 126.44350 (deg.)
    Dec (J2000) = -20:15:33.6  = -20.25933 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

There is a catalogued star at a distance of 1.3 arcsec. The extrapolated
brightness using the SED from the Vizier photometry tool
(
http://cdsportal.u-strasbg.fr/gadgets/ifr?url=http://cdsportal.unistra.fr/widgets/SED_plotter.xml&SED_plot_object=126.442680%2C%20-20.259685&SED_plot_radius=2
)
shows a brightness consistent with that of the white count rate seen at
several
ks after the trigger. We subtract here therefore the late time count rate
in the
following preliminary UVOT photometry of this GRB, knowing that this has to
be
refined using truely late time data. Where we did not have a late time
measurement yet available, the photometry will be reported in due time.

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              131          281          147         16.0 +/- 0.1
b                 5684         5884          197         21.6 +/- 0.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).

The afterglow was also discovered by NOT (Malasani et al. GCN Circ. 24492).


GRB_name: GRB190510A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24497
SUBJECT: IPN triangulation of GRB 190510A (short)
DATE:    19/05/12 07:36:44 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

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

and

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

The short-duration GRB 190510A was detected by Fermi (GBM trigger
579176361), Konus-Wind, and Swift (BAT) at about 37156 s UT (10:19:16).
The burst was outside the coded field of view of the BAT.

We have triangulated this GRB to a Konus-GBM annulus centered at
RA(2000)=34.022 deg (02h 16m 05s)  Dec(2000)=+13.078 deg (+13d 04' 42"),
whose radius is 89.425 +/- 0.966 deg (3 sigma).

The annulus is inconsistent with the GW compact binary merger candidate
event S190510g (The LIGO Scientific Collaboration and the Virgo
Collaboration GCN Circ. 24442).

This annulus may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB190510_T37156/IPN/

The time history and spectrum will be given in forthcoming
GCN Circulars.


GRB_name: GRB190511A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24498
SUBJECT: GRB 190511A: Swift-XRT refined Analysis
DATE:    19/05/12 07:42:36 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernadini
(INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU),
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U.
Leicester) and M.G. Bernardini report on behalf of the Swift-XRT team:

We have analysed 4.0 ks of XRT data for GRB 190511A (Bernardini et al.
GCN Circ. 24472), from 129 s to 46.3 ks after the  BAT trigger. The
data comprise 188 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 24481).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.177 (+0.031, -0.028).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.07 (+0.08, -0.07). The
best-fitting absorption column is  consistent with the Galactic value
of 1.1 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 2.12 (+0.24, -0.23) and a best-fitting absorption
column of 1.6 (+0.7, -0.5) x 10^21 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.2 x 10^-11 (4.5 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.6 (+0.7, -0.5) x 10^21 cm^-2
Galactic foreground: 1.1 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.12 (+0.24, -0.23)

If the light curve continues to decay with a power-law decay index of
1.177, the count rate at T+24 hours will be 9.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x
10^-13 (4.2 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/00903158.

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


GRB_name: GRB190511A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24499
SUBJECT: GRB 190511A: en 
DATE:    19/05/12 10:18:31 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

Hola Alberto,

Han encontrado la contrapartida de este GRB, en coordenadas:

RA = 08:25:46.46
Dec = -20:15:33.4

estando en mag. 20 13 h despuÃ©s, con lo que tuvo que ser bastante
brillante.

Como fue a las 07:14:24.36 UT del 11 de mayo, igual lo tenemos
desde B3 (N. Zelanda). Si la cÃºpula estaba abierta y hacÃ­a buen
tiempo, claro.

Un abrazo desde Nanjing,

Alberto

El 2019-05-11 21:15, GCN Circulars escribiÃ³:
> TITLE:   GCN CIRCULAR
> NUMBER:  24483
> SUBJECT: GRB 190511A: Fermi-LAT detection
> DATE:    19/05/11 13:15:11 GMT
> FROM:    Magnus Axelsson at Stockholm U.  <magaxe@kth.se>
> 
> M. Axelsson (KTH and Stockholm Univ.), F. Longo (Univ. and INFN
> Trieste), M. Arimoto (Kanazawa Univ.) and F. Dirirsa (Univ. of
> Johannesburg) report on behalf of the Fermi-LAT team:
> 
> On May 11, 2019, Fermi-LAT detected high-energy emission from GRB
> 190511A, which was also detected by Fermi-GBM (trigger 579251669 /
> 190511302; GCN 24482) and Swift (GCNs 24472 and 24481).
> 
> The best LAT on-ground location is found to be
> 
> RA, Dec 126.36, -20.25 (degrees, J2000)
> 
> with an error radius of 0.2 deg (90% containment, statistical error 
> only).
> This was 24 deg from the LAT boresight at the time of the GBM trigger:
> 
> T0 =  07:14:24.36 UT.
> 
> The data from the Fermi-LAT show a significant increase in the event
> rate after the GBM trigger that is spatially correlated with the GBM
> emission with high significance and consistent with the Swift
> location.
> 
> The photon flux above 100 MeV in the time interval 0-1400s after the
> GBM trigger is 3.6e-6 ph/cm2/s.
> 
> The estimated photon index above 100 MeV is -2.0 +/- 0.2.
> 
> The Fermi-LAT point of contact for this burst is Feraol Dirirsa
> (fdirirsa@uj.ac.za<mailto:fdirirsa@uj.ac.za>).
> 
> 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: GRB190512A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24500
SUBJECT: GRB 190512A: Fermi GBM Final Real-time Localization
DATE:    19/05/12 14:51:00 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 14:39:59 UT on 12 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190512A (trigger 579364804.721872 / 190512611).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 80.3, Dec = -10.7 (J2000 degrees, equivalent to J2000 05h 21m, -10d 41'), with a statistical uncertainty of 3.0 degrees.

The angle from the Fermi LAT boresight is 25.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190512611/quicklook/glg_skymap_all_bn190512611.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190512611/quicklook/glg_healpix_all_bn190512611.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190512611/quicklook/glg_lc_medres34_bn190512611.gif


GRB_name: GRB190512A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24501
SUBJECT: GRB 190512A: Swift detection of a burst
DATE:    19/05/12 14:51:17 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

M. G. Bernardini (INAF-OAB), J. A. Kennea (PSU),
H. A. Krimm (NSF/USRA), A. Melandri (INAF-OAB),
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 14:40:09 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190512A (trigger=903357).  The BAT on-board calculated location is 
RA, Dec 82.440, -7.574 which is 
   RA(J2000) = 05h 29m 46s
   Dec(J2000) = -07d 34' 25"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a FRED-profile
structure with a duration of about 30 sec.  The peak count rate
was ~1000 counts/sec (15-350 keV), at ~6 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 18:41 UT on 2019 July 21. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is M. G. Bernardini (grazia.bernardini AT brera.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: GRB190511A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24502
SUBJECT: GRB 190511A: Swift-BAT refined analysis
DATE:    19/05/12 16:15:20 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

S. D. Barthelmy (GSFC),  M. G. Bernardini (INAF-OAB), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA),  A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190511Atrigger #903158)
(Bernardini, et al., GCN Circ. 24472).  The BAT ground-calculated position is
RA, Dec = 126.443, -20.252 deg which is 
  RA(J2000)  =  08h 25m 46.2s 
  Dec(J2000) = -20d 15' 05.6" 
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 9%.

The mask-weighted light curve shows a complex, multi-peaked structure,
starting at about T-25 sec, peaking at T+0 sec and declining to background
by T+10 sec.  The spacecraft slewed away from the burst position by 
T+475 sec.  T90 (15-350 keV) is 27.7 +- 2.4 sec (estimated error including 
systematics).

The time-averaged spectrum from T-24.27 to T+6.88 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.19 +- 0.10.  The fluence in the 15-150 keV band is 7.4 +- 0.5 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.36 sec in the 15-150 keV band
is 6.2 +- 1.2 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/903158/BA/


GRB_name: GRB190512A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24510
SUBJECT: GRB 190512A: Fermi GBM observation
DATE:    19/05/12 21:31:08 GMT
FROM:    Cori Fletcher at USRA  <cfletcher@usra.edu>

C. Fletcher (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 14:39:59.72 UT on 12 May 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190512A (trigger 579364804 / 190512611)
which was also detected by the Swift/BAT
(Bernardini et al. 2019, GCN 24501)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 24 degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 28 s (50-300 keV).
The time-averaged spectrum from T0-4.1 s to T0+27.7 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.4 +/- 0.2 and
the cutoff energy, parameterized as Epeak, is 110 +/- 25 keV

The event fluence (10-1000 keV) in this time interval is
(2.4 +/- 0.3)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.13 s in the 10-1000 keV band
is 2.0 +/- 0.3 ph/s/cm^2."

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
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: GRB190512A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24520
SUBJECT: GRB 190512A: Swift-BAT refined analysis
DATE:    19/05/13 16:35:27 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),  M. G. Bernardini (INAF-OAB),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190512A (trigger #903357)
(Bernardini, et al., GCN Circ. 24501).  The BAT ground-calculated position is
RA, Dec = 82.402, -7.582 deg which is 
  RA(J2000)  =  05h 29m 36.5s 
  Dec(J2000) = -07d 34' 56.1" 
with an uncertainty of 2.9 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 83%.

The mask-weighted light curve shows a single FRED-shaped profile, starting at
T-12 sec, peaking close to T+0 sec, and slowly decaying to background by 
T+50 sec.  T90 (15-350 keV) is 40.1 +- 11.3 sec (estimated error including systematics).

The time-averaged spectrum from T-9.70 to T+43.31 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.07 +- 0.14.  The fluence in the 15-150 keV band is 1.3 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-2.78 sec in the 15-150 keV band
is 1.0 +- 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/903357/BA/


GRB_name: GRB190510A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24533
SUBJECT: Konus-Wind observation of GRB 190510A
DATE:    19/05/14 09:55:27 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 190510A
(IPN triangulation: Kozlova et al., GCN 24497)
triggered Konus-Wind at T0=37156.266 s UT (10:19:16.266).

The burst light curve shows a multipeaked structure
which started at T0-0.2 s and had a total duration of ~ 0.6 s.

As observed by Konus-Wind, the burst
had a fluence of 2.36(-0.29,+0.38)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.044 s,
of 8.58(-2.57,+2.72)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the bulk of the burst emission was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modeling the KW 3-channel time-integrated spectrum
(from T0-0.220 s to T0+0.342 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = 0.5 (-0.54,+1.01), and Ep = 574 (-93,+105) keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190510_T37156/

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB190511A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24534
SUBJECT: Konus-Wind observation of GRB 190511A
DATE:    19/05/14 10:00:01 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 190511A
(Swift-BAT detection: Bernardini et al., GCN Circ. 24472,
Barthelmy et al., GCN Circ. 24502;
Fermi-GBM observation: Kienlin et al., GCN Circ. 24482;
Fermi-LAT detection: Axelsson et al., GCN Circ. 24483)
triggered Konus-Wind at T0=26067.524 s UT (07:14:27.524).

The burst light curve shows a multipeaked structure
which started at ~T0-2.6 s and had a total duration of ~31.8 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.93(-0.11,+0.12)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+21.936 s,
of 3.81(-0.90,+0.91)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+33.024 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.69(-0.16,+0.17)
and Ep = 185(-15,+18) keV (chi2 = 49/58 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 = 48/57 dof)

The spectrum near the maximum count rate
(measured from T0+16.640 to T0+24.832 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model
with  alpha = -0.52(-0.23,+0.26)
and Ep = 193(-20,+26) keV (chi2 = 53/58 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.0
(chi2 = 53/57 dof)

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190511_T26067/

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


GRB_name: GRB180416D
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24536
SUBJECT: GRB 180416D: AstroSat CZTI detection
DATE:    19/05/14 11:37:22 GMT
FROM:    Tanazza Khanam at IUCAA  <tanazza@iucaa.in>

Y. Sharma and V. Bhalerao (IIT-B), T. Khanam, V. Sharma and A. Vibhute (IUCAA), D. Bhattacharya (IUCAA), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of long duration GRB 180416D in the 40-200 keV energy range. The light curve shows weak multiple peak emission starting at 04:25:07 (UT). The measured peak count rate is 130 cts/s above the background in combined data of four quadrants, with a total of 6014 cts. The local mean background count rate was 525 cts/s. Using cumulative rates, we measure a T90 of 96.6 s.

The GRB was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range with 165 cts/s peak count rate above background in combined data of four quadrants.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190510B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24538
SUBJECT: GRB 190510B: AstroSat CZTI detection
DATE:    19/05/14 12:45:27 GMT
FROM:    Prachee Ghumatkar at IUCAA/AstroSat  <prachee@iucaa.in>

P. Ghumatkar, V. Sharma, T. Khanam, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a GRB 190510B, which was also detected by Global-MASTER Net (Lipunov V. et al, GCN #24439).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 02:52:21.5 UT. The measured peak count rate associated with the burst is 487 cts/s above the background in the combined data of four quadrants, with a total of 185 cts. The local mean background count rate was 103 cts/s. Using cumulative rates, we measure a T90 of 19.9 s.

It was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190515A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24550
SUBJECT: GRB 190515A: Fermi GBM Final Real-time Localization
DATE:    19/05/15 04:44:50 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 04:33:03 UT on 15 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190515A (trigger 579587588.135176 / 190515190).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 137.2, Dec = 39.3 (J2000 degrees, equivalent to J2000 09h 08m, 39d 17'), with a statistical uncertainty of 5.0 degrees.

The angle from the Fermi LAT boresight is 35.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190515190/quicklook/glg_skymap_all_bn190515190.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190515190/quicklook/glg_healpix_all_bn190515190.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190515190/quicklook/glg_lc_medres34_bn190515190.gif


GRB_name: GRB190510A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24552
SUBJECT: GRB 190510A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/05/15 14:11:57 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

V. Pal'shin, A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN),  Y. Asaoka, S. Ozawa,
S. Torii (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 short GRB 190510A (Fermi GBM Final Real-time Localization: The Fermi
GBM team, GCN Circ. 24449; IPN triangulation: Kozlova et al.,
GCN Circ. 24497; Konus-Wind observation: Kozlova et al., GCN Circ. 24533)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 10:19:15.735 UTC
on 10 May 2019. The burst signal was seen mainly by the SGM detector.

The burst light curve shows a single multi-peaked pulse which starts at
T+0.29 sec and ends at T+0.90 sec. The T90 and T50 durations measured by
the SGM data are 0.54 +- 0.09 sec and 0.29 +- 0.07 sec (40-1000 keV),
respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1241518706/

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


GRB_name: GRB190515B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24553
SUBJECT: GRB 190515B: Swift detection of a burst
DATE:    19/05/15 16:17:18 GMT
FROM:    Michael Moss at George Washington U  <mikejmoss3@gmail.com>

M. J. Moss (George Washington University), C. Gronwall (PSU),
J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), M. H. Siegel (PSU) and A. Tohuvavohu (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 16:04:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190515B (trigger=903845).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 98.840, +52.295 which is 
   RA(J2000) = 06h 35m 22s
   Dec(J2000) = +52d 17' 41"
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 20 sec.  The peak count rate
was ~800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 16:05:43.7 UT, 82.4 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 98.84892, 52.31725 which
is equivalent to:
   RA(J2000)  = 06h 35m 23.74s
   Dec(J2000) = +52d 19' 02.1"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 82 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 http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.27
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 7.78e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 92 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 84% 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
0.09. 

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/)

[GCNOPS NOTE(15may19): Per author's request, the GRB name "190515A" was changed
to "190515B" in the Subject lines in the first paragraph.]


GRB_name: GRB190515B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24554
SUBJECT: GRB 190515B: Prompt enhanced Swift-XRT position
DATE:    19/05/15 16:35:25 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 190515B, we find an
enhanced XRT position of the afterglow: RA, Dec: 98.8489, 52.3168 which
is equivalent to:
   RA (J2000)  = 06 35 23.73
   Dec (J2000) = +52 19 00.4
with an uncertainty of 2.2 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/903845.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

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

[GCN OPS NOTE(15may19): Per author's request, the GRB name was changed from 
"190515A" to "190515B" in the Subject line and the first sentence.]


GRB_name: GRB190515B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24555
SUBJECT: Correction to GRB name for Swift trigger 903845
DATE:    19/05/15 18:40:04 GMT
FROM:    Michael Moss at George Washington U  <mikejmoss3@gmail.com>

M. J. Moss (GWU) reports on behalf of the Swift team:

The GRB name reported in M. J. Moss et al. GCN Circ. #24553  (Swift trigger
number: 903845) should be GRB 190515B.

We apologize for any confusion caused.


GRB_name: GRB190515B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24556
SUBJECT: GRB 190515B: Kitab Observatory optical upper limit
DATE:    19/05/15 18:43:38 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Novichonok (KIAM), A. Pozanenko (IKI), E. Mazaeva 
(IKI), A. Volnova (IKI), I. Molotov (KIAM) report on behalf of larger 
IKI GRB FuN   collaboration:

We observed the field of the Swift GRB 190515B (Moss et al., GCN  24553) 
  with RC-36 0.36-m telescope of Kitab Observatory starting on May  15 
(UT) 16:13:02 in  Clear filter.    We do not find any optical source 
neither in the first image, nor in a stacked image  within prompt 
enhanced Swift-XRT position (Evans  et al., GCN  24554).
Preliminary photometry of the field is following.

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

2019-05-15 16:13:02   0.00655    CR     1*90   n/d  n/d       18.6
2019-05-15 16:13:02   0.02686    CR    40*90   n/d  n/d       20.3

The photometry is based on the nearby USNO-B1 (R2) star:
USNO-B1.0_id R2
1422-0205150 15.02

The closest object which is not presented in any catalogs marginally 
detected in our stacked image  has  coordinates   (J2000) 06:35:24.07 
+52:19:12.4 with uncertainty of 1 arcsec in both coordinates and 
brightness of 20.4m (S/N =2). The position of the object is 12 arcsec 
apart from the the center of  prompt enhanced Swift-XRT position (Evans 
et al., GCN  24554). At this time we cannot say about variability of the 
object.

[GCN OPS NOTE(15may19): The GRB anme "190515A" was changed to "190515B"
in the Subject line and in the first sentence.]


GRB_name: GRB190515B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24557
SUBJECT: GRB 190515B: Enhanced Swift-XRT position
DATE:    19/05/15 19:51:47 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 611 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 190515B, 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 = 98.84772, +52.31665 which is equivalent
to:

RA (J2000): 06h 35m 23.45s
Dec (J2000): +52d 18' 59.9"

with an uncertainty of 2.3 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: GRB190515B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24558
SUBJECT: GRB 190515B: Optical observations from OSN
DATE:    19/05/15 22:22:55 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), M. Blazek, L. Izzo, C.C. Thoene, D.A. Kann, K. Bensch (all HETH/IAA-CSIC), A. Sota (IAA-CSIC) report:

We observed the field of GRB 190515B (Moss et al. GCN 24553) with the 1.5m OSN telescope, at Sierra Nevada Observatory (Granada, Spain). The observation started at 21:13 UT (5.15 hr after the burst) when clouds over the observatory allowed, at an airmass of 2, and consisted of 3x300s exposures in I-band.

No new object is detected within the refined XRT error circle (Osborne et al. GCN 24557) down to a 3-sigma limit of I(AB) = 20.5 mag, as compared to stars of the PanSTARRS catalogue.


GRB_name: GRB190515A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24560
SUBJECT: GRB 190515A: Fermi-LAT detection 
DATE:    19/05/16 02:05:30 GMT
FROM:    Daniel Kocevski at GSFC  <dankocevski@gmail.com>

D. Kocevski (NASA/MSFC), M. Axelsson (KTH and Stockholm Univ.), L. Scotton (INFN Torino), E. Burns (NASA/GSFC), and M. Arimoto (Kanazawa Univ.) report on behalf of the Fermi-LAT team: 

At 04:33:03 on 2019-05-15, Fermi-LAT triggered on high-energy emission from short GRB 190515A, which was also detected by Fermi-GBM  (trigger 579587588/190515190).

The best LAT on-ground location is found to be

RA, Dec = 137.687 , 29.276 (J2000) 

with an error radius of 0.907 deg (90% containment, statistical error only). This was 44 deg from the LAT boresight at the time of the trigger and 10 deg from the center of the GBM localization (GCN 24550).

The data from the Fermi-LAT show a significant increase in the event rate that is temporally correlated with the GBM emission with high significance. The highest-energy photon is a 874 MeV event which is observed 3 seconds after the GBM trigger.

The photon flux above 100 MeV in the time interval 0-300s after the GBM trigger is 6.5e-06 ph/cm2/s +/- 2.4e-06. The estimated photon index above 100 MeV is -2.6 +/- 0.5.

The Fermi-LAT point of contact for this burst is Magnus Axelsson (magnusa@fysik.su.se). 

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: GRB190515B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24561
SUBJECT: GRB 190515B: Swift-XRT refined Analysis
DATE:    19/05/16 02:38:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA),
A. Melandri (INAF-OAB), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows
(PSU), A. Tohuvavohu (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester) and report on behalf of the Swift-XRT team: report on
behalf of the Swift-XRT team:

We have analysed 6.3 ks of XRT data for GRB 190515B, from 88 s to 27.5
ks after the  BAT trigger. The data comprise 66 s in Windowed Timing
(WT) mode with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Osborne et al. (GCN Circ.
24557).

The light curve can be modelled with an initial power-law decay with an
index of alpha=3.85 (+0.26, -0.23), followed by a break at T+296 s to
an alpha of 0.38 (+0.11, -0.12).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.26 (+0.33, -0.30). The
best-fitting absorption column is  2.1 (+0.6, -0.5) x 10^21 cm^-2, in
excess of the Galactic value of 1.3 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.06 (+0.24, -0.15)
and a best-fitting absorption column consistent with the Galactic
value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.3 x 10^-11 (4.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.3 (+0.6, -0.0) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      2.06 (+0.24, -0.15)

If the light curve continues to decay with a power-law decay index of
0.38, the count rate at T+24 hours will be 0.027 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.0 x
10^-13 (1.2 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00903845.

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


GRB_name: GRB190515A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24562
SUBJECT: GRB 190515A: Fermi GBM detection
DATE:    19/05/16 04:36:25 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

O.J. Roberts (USRA/NASA-MSFC) reports on behalf of the Fermi GBM Team:

"At 04:33:03.14 UT on the 15th May 2019, the Fermi Gamma-ray Burst Monitor
(GBM)
triggered and located GRB 190515A (trigger 579587588 / 190515190), which was
also detected by the LAT (Kocevski et al. 2019, GCN 24560)
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight is 44 degrees.

The GBM light curve shows a bright short spike with a duration (T90)
of about 0.5 s (10-1000 keV). The time-averaged spectrum from
T0-0.26 s to T0+0.38 s is best fit by a power law function with
an exponential high-energy cutoff.  The power law index is
-0.4 +/- 0.2 and the cutoff energy, parameterized as Epeak,
is 960 +/- 251 keV.

The event fluence (10-1000 keV) in this time interval is
(1.233 +/- 0.070)E-06 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.2 s in the 10-1000 keV band
is 8.2 +/- 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: GRB190515A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24563
SUBJECT: GRB 190515A: Insight-HXMT/HE detection
DATE:    19/05/16 07:52:53 GMT
FROM:    Shuo Xiao at IHEP  <xiaoshuo@ihep.ac.cn>

S. Xiao, C. Cai, Q. Luo, Q. B. Yi, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-05-15T04:33:03.000 (T0), Insight-HXMT/HE detected 
GRB 190515A(trigger ID: HEB190515189) in a routine search of the data, 
which was also triggered by Fermi/GBM (GCN#24550), Fermi/LAT (D. Kocevski 
et al., GCN#24560) and Swift/XRT (M. J. Moss et al., GCN#24553). 

The Insight-HXMT/HE light curve mainly consists of single  
pulse with a duration (T90) of 0.44 s measured from T0+0.02 s. 
The 1-ms peak rate, measured from T0+0.20 s, is 5641 cnts/sec. 
The total counts from this burst is 1906 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190515189_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.


GRB_name: GRB190515B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24564
SUBJECT: GRB 190515B: Swift-BAT refined analysis
DATE:    19/05/16 13:28:03 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 190515B (trigger #903845)
(Moss et al., GCN Circ. 24553).  The BAT ground-calculated position is
RA, Dec = 98.826, 52.322 deg which is
   RA(J2000)  =  06h 35m 18.3s
   Dec(J2000) = +52d 19' 17.6"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.

The mask-weighted light curve shows a single-pulse structure that starts at
~T-30 s, peaks at ~T0, and ends at ~T+30 s. T90 (15-350 keV) is 46.4 +-
12.3 sec
(estimated error including systematics).

The time-averaged spectrum from T-30.84 to T+31.02 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.74 +- 0.15.  The fluence in the 15-150 keV band is 1.6 +- 0.1 x 10^-6
erg/cm2.
The 1-sec peak photon flux measured from T-0.39 sec in the 15-150 keV band
is 1.1 +- 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/903845/BA/


GRB_name: GRB190515B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24567
SUBJECT: GRB 190515B: BOOTES-4/MET and 2.2m CAHA optical limits
DATE:    19/05/17 03:26:28 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

Y.-D. Hu, X.-Y. Li, E. Fernandez-Garcia, A. Ayala, A. J. Castro-Tirado 
(IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de 
Malaga), S. Guziy (Univ. of Nikolaev), D. Xiong, Y. Fan, X. Zhao, J. 
Bai, C. Wang, Y. Xin, J. Mao (Yunnan Nacional Astronomical Observatory), 
A. Fernandez and I. Hermelo (CAHA),  on behalf of a larger 
collaboration, report:

Following the detection of GRB 190515B by Swift (Moss et al. GCNC 
24553), the 0.6m BOOTES-4/MET robotic telescope at Lijiang Astronomical 
Observatory (China) automatically responded gathering 9 frames (gâ€™ 
filter, 30s exposures) starting at 16:10:44UT (0.11 hr after trigger). 
In addition, 23 frames at the 2.2m Calar Alto telescope equipped with 
CAFOS (I-band, 120s exposures) were taken starting at 20:45:41 UT (4.69 
h post burst). On the co-added images, no optical afterglow is found 
down to 18.9 mag (g-band) or 22.1 (I-band) respectively at the enhaced 
XRT position (Evans et al. GCNC 24554), in agreement with Belkin et al. 
(GCNC 24556) and de Ugarte Postigo et al. (GCNC 24558). Particularly the 
Calar Alto co-add I-band frame does not detect the marginal object 
reported in GCNC 24556.

We thank the CAHA staff for excellent support.


GRB_name: GRB190515B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24568
SUBJECT: GRB 190515B: Swift/UVOT Upper Limits
DATE:    19/05/17 03:44:52 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and M. J. Moss (George Washington University)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190515B
93 s after the BAT trigger (Moss et al., GCN Circ. 24553).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 24557)
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            93          242          147         >19.9
u_FC               305          555          246         >19.4
white               93          605          167         >20.0
v                  636         4442          216         >18.9
b                  561          754           39         >18.7
u                  305          730          265         >19.5
w1                 685         4722           88         >18.9
m2                 661         4647          216         >19.6
w2                 612         4237          216         >19.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190515A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24575
SUBJECT: GRB 190515A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/05/17 10:26:34 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

S. Sugita, A. Yoshida, T. Sakamoto, V. Pal'shin(AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U),
S. Nakahira (RIKEN),  Y. Asaoka, S. Ozawa,
S. Torii (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 short hard GRB 190515A (Fermi-LAT detection: Kocevski et al.,
GCN Circ. 24560; Fermi GBM detection: Roberts, GCN Circ. 24562)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 04:33:03.330 UTC
on 15 May 2019. The burst signal was seen by all CGBM detectors.

The burst light curve shows a single pulse which starts at T+0 sec,
peaks at T+0.19 sec and ends at T+0.45 sec. The T90 and T50 durations
measured by the SGM data are 0.38 +- 0.14 sec and
0.19 +- 0.06 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1241929925/

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


GRB_name: GRB190517A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24585
SUBJECT: GRB 190517A: Fermi GBM Final Real-time Localization
DATE:    19/05/17 19:41:51 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 19:30:10 UT on 17 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190517A (trigger 579814215.17247 / 190517813).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 270.0, Dec = 25.8 (J2000 degrees, equivalent to J2000 18h 00m, 25d 48'), with a statistical uncertainty of 1.2 degrees.

The angle from the Fermi LAT boresight is 79.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190517813/quicklook/glg_skymap_all_bn190517813.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190517813/quicklook/glg_healpix_all_bn190517813.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190517813/quicklook/glg_lc_medres34_bn190517813.gif


GRB_name: GRB190517A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24586
SUBJECT: Fermi Trigger 579814215 / GRB 190517813 / GRB190517A: BALROG localization
DATE:    19/05/17 19:53:56 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
579814215 at 19:30:10 on 17 May 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 270.6+/-1.6 deg
Decl.(2000.0) = 20.3+/-1.0 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190517813/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190517813/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190517813/json

                        


GRB_name: GRB190511A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24587
SUBJECT: GRB 190511A: Swift/UVOT further analysis
DATE:    19/05/17 20:15:07 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and M. G. Bernardini (INAF-OAB)
report on behalf of the Swift/UVOT team:

In GCN Circ. 24494 (Kuin and Bernardini) we described how we detect
the afterglow of the GRB, but that the photometry was affected by
an object located at a distance of 1.3 arcsec. Further Swift
observations show that the uv-optical afterglow was no longer
detected in white beyond 26ks after the trigger. Data that were taken
after that time are considered template observations that
provide the background contribution to the photometry.

The template net corrected count rates, with instrumental effects
removed, are found to be as follows for a 3" radius circular aperture
at the location of the GRB as reported in GCN 24494:
White = 1.066 +/- 0.031 c/s; u = 0.149 +/- 0.016 c/s;
b = 0.509 +/- 0.061 c/s; uvw2 =  0.011 +/- 0.011 c/s;
v = 0.272 +/- 0.042 c/s; while uvm2 and uvw1 were not observed
until after the afterglow became too faint.

After removal of the template contribution, the following preliminary
detections and 3-sigma upper limits were determined from the count rates
using the zeropoints in the UVOT photometric system (Poole et al. 2008,
MNRAS 383, 627; Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for
the image mode exposures:

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

white              131          281          147          15.96 +/- 0.05
u                  290          385           93          19.62 +/- 0.42
b                 5684         5884          197          > 20.13
white             5888         6088          197          20.61 +/- 0.37
uvw2              6094        11850          518          > 17.81
v                17150        17450          300          > 19.35

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.09 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190519A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24594
SUBJECT: GRB 190519A: Fermi GBM Final Real-time Localization
DATE:    19/05/19 07:36:50 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 07:24:57 UT on 19 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190519A (trigger 579943502.3431 / 190519309).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 114.9, Dec = -35.5 (J2000 degrees, equivalent to J2000 07h 39m, -35d 30'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 85.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190519309/quicklook/glg_skymap_all_bn190519309.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190519309/quicklook/glg_healpix_all_bn190519309.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190519309/quicklook/glg_lc_medres34_bn190519309.gif


GRB_name: GRB190519A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24595
SUBJECT: GRB 190519A: Swift detection of a burst
DATE:    19/05/19 07:46:35 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl@swift.psu.edu>

T. N. Ukwatta (LANL), E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC),
C. Gronwall (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC) and
K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 07:25:39 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190519A (trigger=904394).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 114.764, -38.824 which is 
   RA(J2000) = 07h 39m 03s
   Dec(J2000) = -38d 49' 26"
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. In addition, there might be
a weaker pulse that starts at ~ T-50 s. The peak count rate
was ~5500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 07:27:04.3 UT, 85.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 114.7673,
-38.8052 which is equivalent to:
   RA(J2000)  = 07h 39m 04.14s
   Dec(J2000) = -38d 48' 18.7"
with an uncertainty of 2.0 arcseconds (radius, 90% containment). This
location is 68 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 http://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 (4.31 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 3.6
(+2.17/-1.96) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 4.35e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
150 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 19.2 mag. 
Results from the list of sources generated on-board are not available at this
time. No correction has been made for the expected extinction corresponding to
E(B-V) of 0.42. 

Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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: GRB190519A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24596
SUBJECT: GRB 190519A: Fermi GBM observation
DATE:    19/05/19 12:27:18 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:

"At 07:24:57.34 UT on 19 May 2019, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GGRB 190519A (trigger 579943502 / 190519309), which
was also detected by the Swift/BAT (Ukwatta et al. 2019, GCN 24595). The 
GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 86.4 degrees.

The GBM light curve shows a multi-peaked structure with a duration (T90) 
of about 46 s (50-300 keV). The time-averaged spectrum from T0-3.072 s to T0+50.177 s is
best fit by a power law function with an exponential high-energy cutoff.  
The power law index is -1.06 +/- 0.02 and the cutoff energy, 
parameterized as Epeak, is 112 +/- 3 keV

The event fluence (10-1000 keV) in this time interval is
(3.16 +/- 0.04)E-05 erg/cm^2. The 1.024 sec peak photon flux measured
starting from T0+41.9847 s in the 10-1000 keV band is 35.8 +/- 0.6 ph/s/cm^2.

A Band function fits the spectrum equally well with Epeak= 108 +/- 3 keV, 
alpha = -1.04 +/- 0.03 and beta = -3.1 +/- 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: GRB190519A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24597
SUBJECT: GRB 190519A: Enhanced Swift-XRT position
DATE:    19/05/19 16:44:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 1496 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 190519A, 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 = 114.76757, -38.80540 which is equivalent
to:

RA (J2000): 07h 39m 4.22s
Dec (J2000): -38d 48' 19.4"

with an uncertainty of 1.6 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: GRB190519A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24606
SUBJECT: GRB 190519A: Swift-BAT refined analysis
DATE:    19/05/19 22:10:22 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 190519A (trigger #904394)
(Ukwatta et al., GCN Circ. 24595).  The BAT ground-calculated position is
RA, Dec = 114.758, -38.813 deg which is
   RA(J2000)  =  07h 39m 01.9s
   Dec(J2000) = -38d 48' 46.6"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 8%.

The mask-weighted light curve shows a multi-peaked structure that starts at
~T-60 s and ends at ~T+15 s. The main peak occurs at ~T0. T90 (15-350 keV)
is 45.58 +- 2.86 sec (estimated error including systematics).

The time-averaged spectrum from T-56.97 to T+14.79 sec is best fit by a
power law
with an exponential cutoff.  This fit gives a photon index 1.32 +- 0.24,
and Epeak of 90.0 +- 35.0 keV (chi squared 76.36 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 1.8 +- 0.1 x 10^-5 erg/cm2
and the 1-sec peak flux measured from T-0.21 sec in the 15-150 keV band is
20.6 +- 1.7 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.72 +- 0.06 (chi squared 85.04 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/904394/BA/


GRB_name: GRB190519A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24608
SUBJECT: GRB 190519A: Swift-XRT refined Analysis
DATE:    19/05/20 02:18:41 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte (PSU), P.A.
Evans (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester) and T.N. Ukwatta report on behalf of the Swift-XRT team:

We have analysed 7.0 ks of XRT data for GRB 190519A (Ukwatta et al. GCN
Circ. 24595), from 91 s to 46.8 ks after the  BAT trigger. The data
comprise 100 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 24597).

The late-time light curve (from T0+13.7 ks) can be modelled with a
power-law decay with a decay index of alpha=1.33 (+/-0.28).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.34 (+0.20, -0.18). The
best-fitting absorption column is  6.5 (+1.2, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 4.3 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.79 (+0.13, -0.12)
and a best-fitting absorption column of 6.8 (+1.1, -1.0) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.9 x 10^-11 (7.5 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.8 (+1.1, -1.0) x 10^21 cm^-2
Galactic foreground: 4.3 x 10^21 cm^-2
Excess significance: 4.3 sigma
Photon index:      1.79 (+0.13, -0.12)

If the light curve continues to decay with a power-law decay index of
1.33, the count rate at T+24 hours will be 0.020 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x
10^-12 (1.5 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00904394.

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


GRB_name: GRB190519A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24611
SUBJECT: GRB 190519A: CALET Gamma-Ray Burst Monitor detection
DATE:    19/05/20 11:12:25 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

K. Yamaoka (Nagoya U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (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 bright GRB 190519A (Swift-BAT trigger #904394: Ukwatta et al.,
GCN Circ. 24595, Lien et al., GCN Circ. 24606; Fermi GBM observation:
von Kienlin, GCN Circ. 24596) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 07:24:59.459 UTC on 19 May 2019.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a broad multi-peaked pulse which starts
at T-4.0 sec and ends at ~T+24 sec, followed by a bright double-peaked
pulse, which starts at T+31.8 sec, peaks at 40.1 sec and ends
at T+45.3 sec. The T90 and T50 durations measured by the SGM data are
42.8 +- 2.5 sec and 24.6 +- 3.5 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1242285834/

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


GRB_name: GRB190519A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24612
SUBJECT: GRB 190519A: Swift/UVOT Upper Limits
DATE:    19/05/20 13:56:20 GMT
FROM:    Jeffrey Gropp at PSU  <jdg44@psu.edu>

J. D. Gropp (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190519A
150 s after the BAT trigger (Ukwatta et al., GCN Circ. 24595).
No optical afterglow consistent with the enhanced XRT position
(Ukwatta et al. GCN Circ. 24597)
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

u_FC               150          400          246         >18.9
v                  456         2571          272         >18.7
b                  406         2520          272         >19.7
u                  150         2495          646         >19.5
w1                 505         2610          262         >19.5
m2                 481         2595          272         >19.1
w2                 432         2546          272         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.42 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190519A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24613
SUBJECT: GRB 190519A: AstroSat CZTI detection
DATE:    19/05/20 16:34:42 GMT
FROM:    Prachee Ghumatkar at IUCAA/AstroSat  <prachee@iucaa.in>

P. Ghumatkar, V. Sharma, T. Khanam, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 190519A, which was also detected by Fermi GBM (GCN #24594).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 07:25:43 UT. The measured peak count rate associated with the burst is 185 cts/s above the background in the combined data of four quadrants, with a total of 706 cts. The local mean background count rate was 622 cts/s. Using cumulative rates, we measure a T90 of 45.2 s. In preliminary analysis, we find that 429 Compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190519A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24652
SUBJECT: Konus-Wind observation of GRB 190519A
DATE:    19/05/22 12:54:15 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova@mail.ioffe.ru>

A. Tsvetkova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 190519A
(Fermi GBM observation: Fermi GBM team, GCN 24594; von Kienlin, GCN 24596;
Swift detection: Ukwatta et al., GCN 24595; Lien et al., GCN 24606;
CALET Gamma-Ray Burst Monitor detection: Yamaoka et al., GCN 24611;
AstroSat CZTI detection: Ghumatkar et al., GCN 24613)
triggered Konus-Wind at T0=26732.082 s UT (07:25:32.082).

The burst light curve shows two pulses.
The first one starts at T0-39.0 s and ends at T0-3.7 s.
The second, bright, double-peaked pulse starts at T0-3.7 s and ends at 
T0+11.6 s.
The total duration of the burst is ~51 s.
The emission is seen up to ~1.5 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.20(-0.16,+0.18)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+6.752 s,
of 5.80(-1.01,+1.01)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the main pulse
(measured from T0 to T0+15.616 s)
is best fit in the 20 keV - 1.5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.05(-0.09,+0.10),
and Ep = 125(-6,+7) keV (chi2 = 67/60 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -3.05 (chi2 = 67/59 dof).

The spectrum near the peak count rate
(measured from T0+0.256 to T0+7.424 s)
is best fit in the 20 keV - 1.5 MeV range
by the power law with exponential cutoff model
with  alpha = -0.93(-0.10,+0.10),
and Ep = 136(-6,+7) keV (chi2 = 65/60 dof).
Fitting by the GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index:
beta < -2.96 (chi2 = 64/59 dof).

Modeling the K-W 3-channel spectrum of the initial pulse
(measured from T0-38.980 s to T0-3.652 s)
by a simple power law yields the photon index of 2.21(-0.07,+0.08),
chi2 = 0.94/1 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190519_T26732/

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


GRB_name: GRB190525A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24662
SUBJECT: GRB 190525A: Fermi GBM Final Real-time Localization
DATE:    19/05/25 00:57:35 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 SHORT GRB

At 00:45:47 UT on 25 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190525A (trigger 580437952.651712 / 190525032).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 338.0, Dec = 5.5 (J2000 degrees, equivalent to J2000 22h 32m, 5d 30'), with a statistical uncertainty of 4.0 degrees.

The angle from the Fermi LAT boresight is 43.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190525032/quicklook/glg_skymap_all_bn190525032.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190525032/quicklook/glg_healpix_all_bn190525032.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190525032/quicklook/glg_lc_medres34_bn190525032.gif


GRB_name: GRB190525A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24665
SUBJECT: GRB 190525A: Insight-HXMT/HE detection
DATE:    19/05/27 00:07:03 GMT
FROM:    Ce Cai at IHEP  <caice@ihep.ac.cn>

C. Cai, S. Xiao, Q. Luo, Q. B. Yi, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-05-25T00:45:47.65 (T0), Insight-HXMT/HE detected 
GRB 190525A(trigger ID: HEB190525031) in a routine search of the data, 
which was also triggered by Fermi/GBM (GCN #24662). 

The Insight-HXMT/HE light curve mainly consists of single  
pulse with a duration (T90) of 0.90 s measured from T0-0.20 s. 
The 1-ms peak rate, measured from T0+0.53 s, is 1719 cnts/sec. 
The total counts from this burst is 753 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190525031_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.


GRB_name: GRB190525A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24667
SUBJECT: GRB 190525A: AstroSat CZTI detection
DATE:    19/05/27 08:49:16 GMT
FROM:    Prachee Ghumatkar at IUCAA/AstroSat  <prachee@iucaa.in>

P. Ghumatkar, V. Sharma, T. Khanam, D. Bhattacharya and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a short GRB 190525A, which was also detected by Fermi GBM (GCN #24662), Global MASTER-Net (GCN #24663) and Insight-HXMT/HE (GCN #24665).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range at 00:45:47 UTC.
The CZTI light curve shows a weak detection in the 40-200 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190530A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24676
SUBJECT: GRB 190530A: Fermi GBM Final Real-time Localization
DATE:    19/05/30 10:29:16 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 10:19:08 UT on 30 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190530A (trigger 580904353.903198 / 190530430).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 116.9, Dec = 34.0 (J2000 degrees, equivalent to J2000 07h 47m, 34d 00'), 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:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190530430/quicklook/glg_skymap_all_bn190530430.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190530430/quicklook/glg_healpix_all_bn190530430.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190530430/quicklook/glg_lc_medres34_bn190530430.gif


GRB_name: GRB190530A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24677
SUBJECT: Fermi Trigger 580904353 / GRB 190530430 / GRB190530A: BALROG localization
DATE:    19/05/30 10:54:24 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
580904353 at 10:19:08 on 30 May 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 120.7+/-0.3 deg
Decl.(2000.0) = 36.1+/-0.2 deg
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190530430/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190530430/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190530430/json

                        


GRB_name: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24678
SUBJECT: GRB 190530A: AGILE-MCAL detection
DATE:    19/05/30 16:10:42 GMT
FROM:    Fabrizio Lucarelli at SSDC/INAF-OAR  <fabrizio.lucarelli@ssdc.asi.it>

F. Lucarelli, C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS,
and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista,
M. Feroci, G. Piano, A. Ursi (INAF/IAPS), A. Bulgarelli, V. Fioretti, F. Fuschino,
N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen
University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo
(Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of
the AGILE Team:

The AGILE Mini-CALorimeter (MCAL) detected GRB 190530A at T0 = 2019-05-30
10:19:16.003 +/- 0.01 s (UTC), which was also detected by Fermi/GBM (GCN #24676).
The AGILE MCAL trigger occured around 8 s after the FERMI/GBM trigger.

An automatic MCAL Event Notice was also issued and is available at the GCN link:
https://gcn.gsfc.nasa.gov/agile_mcal.html

The event lasted about 12 s and released a total number of ~30900 counts in the
detector (in the 0.4-100 MeV energy range), above an average background rate of 637
counts/s.

The light curve shows two structures and several peaks, with a prompt emission
lasting around 1.6s and then, after about 5 s from T0, a second structure lasting for
around 7 s with the highest peak at around T0+7s.

The plot of the AGILE-MCAL light curve can be found at:
https://tools.ssdc.asi.it/ImgView/Agile/GRB190530A_AGILE-MCAL16

Bright emission in the 17-60 keV energy range is also detected by the SuperAGILE
instrument on-board of AGILE.

The GRB is clearly detected also by the AGILE scientific ratemeters: in particular,
the Anti-Coincidence (50-200 keV), SuperAGILE (20-60 keV), and MCAL (0.4-100 MeV)
ratemeters.

The AGILE-MCAL detector is a CsI detector with a 4 pi FoV, sensitive in the energy
range 0.4-100 MeV. Additional analysis of AGILE data is in progress.


GRB_name: GRB190530A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24679
SUBJECT: GRB 190530A: Fermi-LAT detection  
DATE:    19/05/30 18:20:18 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

F. Longo (University and INFN, Trieste), J. L. Racusin (NASA/GSFC), N. Omodei (Stanford), and 
E.Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi-LAT Collaboration:

At 10:19:08 UT on 2019-05-30, Fermi-LAT triggered on high-energy emission from long GRB 190530A, 
which was also detected by Fermi-GBM (GCN 24676) and AGILE-MCAL (GCN 24678).

The best LAT on-ground location is found to be:
RA, Dec = 120.76, 35.5 (J2000) 
with an error radius of 0.12 deg (90% containment, statistical error only).

This was 63 deg from the LAT boresight at the time of the trigger and 3.5 deg from the center of the GBM 
localization (GCN 24676).

The data from the Fermi-LAT show a significant increase in the event rate that is temporally correlated with 
the GBM emission with high significance.

The highest-energy photon is a 8.7 GeV event which is observed 96 seconds after the GBM trigger.
The photon flux above 100 MeV in the time interval 0-200s after the GBM trigger is 2.9 e-04 ph/cm2/s 
+/- 2.9 e-05.

The estimated photon index above 100 MeV is -2.7 +/- 0.1.

The Fermi-LAT point of contact for this burst is Francesco Longo (francesco.longo@ts.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: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24680
SUBJECT: GRB 190530A: MASTER OT detection
DATE:    19/05/30 19:03:26 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov (Lomonosov MSU), D.Svinkin (Ioffe Institute),
O.Gress, A.Kuznetsov, N.Tyurina, V.Kornilov, D.Vlasenko, V.Vladimirov, D.Zimnukhov, P.Balanutsa, F.Balakin, E. Gorbovskoy, A. Chasovnikov, V.Topolev, D.Kuvshinov
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, SJNU)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),

O. Gress, N.M. Budnev, O.Ershova, Yu.Ishmuhametova, S.Yazev (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),

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

MASTER-Kislovodsk robotic telescope  (MASTER Global Robotic Net http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy,vol. 2010, 30L)
automatically was pointed to the GRB190530A Fermi LAT localization 
(Longo et al GCN 24679) (also inspected BALROG localization Biltzinger et al. GCN 24677  and  Fermi team error-box GCN 24676)
at 2019-05-30 18:12:10 (sun altitute= -16deg., alert_altitute=23deg.)

We detect MASTER OT J080207.73+352847.7  (RA,Dec2000)=08h 02m 07.73s +35d 28m 47.7s
with m_OT=16.7m (but in 3.8" there is optical source  at PANSTARRs images 
with  rmag=20.9, gmag=22.6)

OT is inside Barlog error box (GCN 24677).
The covered map and OT place is available at
https://master.sai.msu.ru/site/master2/event.php?id=1034468


Observation and reduction will be continued.
The message may be cited.


GRB_name: GRB190530A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24681
SUBJECT: GRB 190530A: Swift ToO observations
DATE:    19/05/30 19:42:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 190530A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020893

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: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24683
SUBJECT: GRB 190530A: AGILE/GRID analysis
DATE:    19/05/30 20:36:47 GMT
FROM:    Francesco Verrecchia at ASDC  <francesco.verrecchia@ssdc.asi.it>

F. Verrecchia, F. Lucarelli, C. Pittori (SSDC, and INAF/OAR), G. Piano (INAF/IAPS),
M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), M. Cardillo, Y. Evangelista,
A. Ursi (INAF/IAPS), (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino
(INAF/OAS), M. Marisaldi (INAF/OAS, and Bergen University), M. Pilia, A. Trois
(INAF/OA-Cagliari), F. Longo (Univ. Trieste and INFN Trieste), I. Donnarumma
(ASI), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team:

The Gamma-Ray Imaging Detector (GRID) of AGILE detected a gamma-ray transient
temporally coincident with the long  GRB 190530A reported by Lucarelli et al.,
GCN #24678 and also detected and localized by Fermi/GBM (GCN #24676) and
Fermi/LAT (GCN #24679).

A preliminary GRID analysis in the energy range 30 MeV - 1 GeV shows a
detection with a statistical significance of about 4 sigma, at the sky position
R.A., Decl. (J2000): 120,+34  5 deg (Galactic coordinates l,b: 187,+28 deg),
over a time integration of 500 s starting from the T0 of GRB 190530A.

This preliminary estimated position was above 30 deg from the GRID boresight.

These measurements were obtained with AGILE observing a large portion of
the sky in spinning mode. Additional analysis of AGILE data is in progress.


GRB_name: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24684
SUBJECT: GRB 190530A: Bright afterglow confirmed by OSN
DATE:    19/05/30 21:58:06 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

D. A. Kann, L. Izzo (both HETH/IAA-CSIC), A. de Ugarte Postigo 
(HETH/IAA-CSIC, DARK/NBI), M. Blazek, C. C. Thoene, K. Bensch (all 
HETH/IAA-CSIC), and V. Casanova (IAA-CSIC) report:

We observed the afterglow position (Lipunov et al., GCN 24680) of the 
extremely bright GRB 190530A (GBM detection and localization: Fermi GBM 
team, GCN 24676, Biltzinger et al., GCN 24677; Fermi-LAT localization: 
Longo et al., GCN 24679; Agile-MCAL/GRID detections: Lucarelli et al., 
GCN 24678, Verecchia et al., GCN 24683) with the 1.5-m telescope of the 
Sierra Nevada Observatory (OSN), Spain. The afterglow is well-detected.

We measure the following AB magnitude:

Rc = 17.63  +- 0.10 mag at 0.437314 days after the GRB.

The magnitude were derived against 1 nearby star from the SDSS catalog, 
using the transformation equations of Lupton (2005), and transformed 
back into AB mag.

We note this is an exceedingly bright afterglow, further follow-up is 
encouraged despite the bad visibility.


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24686
SUBJECT: GRB 190530A: NOT photometry and spectroscopy
DATE:    19/05/30 22:52:43 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14@hi.is>

K. E. Heintz (Univ. of Iceland), J. P. U. Fynbo (DAWN/NBI), A. de Ugarte Postigo (HETH/IAC and DARK/NBI), D. B. Malesani (DTU Space), J. Selsing (DAWN/NBI), B. Milvang-Jensen (DAWN/NBI) and S. Moran (NOT and Univ. of Turku), report on behalf of a larger collaboration:

We observed the optical counterpart (Lipunov et al., GCN 24680) of the bright Fermi-LAT GRB 190530A (Longo et al., GCN 24679), with the 2.5-m Nordic Optical Telescope (NOT) equipped with ALFOSC, starting at 21:21:12 UT on 30 May 2019. We obtained 30 s images in each of the g, r, i, and z-filters and measure magnitudes of: m(g) = 17.72 +/- 0.03, m(r) = 17.53 +/- 0.02, m(i) = 17.41 +/- 0.02, and m(z) = 17.37 +/- 0.03 AB mag at 11.2 hr post-burst. The calibration was performed using local Pan-STARRS stars in the GRB field. This apparent magnitudes are not corrected for foreground extinction.

We subsequently obtained spectroscopy for a total of 2x600 s, using grism #4 and covering the wavelength range 3650-9450 AA. The spectrum shows a blue, power-law continuum from 3900 AA to 9000 AA. We do not detect any significant absorption or emission lines in our low-resolution spectrum, but based on the detected continuum we infer an upper limit on the redshift of z < 2.2. We encourage the community to obtain spectra of this GRB with bluer wavelength coverage.


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24687
SUBJECT: GRB 190530A: OAJ optical detection
DATE:    19/05/30 23:12:12 GMT
FROM:    Luca Izzo at IAA-CSIC  <luca.izzo@gmail.com>

L. Izzo (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, M. Blazek, C. C. Thoene, K. Bensch (all HETH/IAA-CSIC), J.L. Lamadrid, F. LÃ³pez-MartÃ­nez, M. C. DÃ­az-MartÃ­n andH. Vazquez Ramio (all CEFCA) report:

We observed the field of GRB 190530A (Fermi-GBM team, GCN 24676; Biltzinger et al., GCN 24677; Longo et al., GCN 24679; Lucarelli et al., GCN 24678; Verecchia et al., GCN 24683) with the 0.8m telescope of the Observatorio Astrofisico de Javalambre (Teruel, Spain). Observations consisted of a series of 300 s g'r'i' exposures, starting at 20:53:37 UT (0.44 days after the GRB trigger). We do not detect any source within the LAT error circle (Longo et al., GCN 24679) itself down to the DSS2 limit.

The afterglow reported by Lipunov et al. (GCN 24680) is clearly detected at the following position (J2000, +/-0.5"):

RA =  08:02:07.84
Dec. = +35:28:47.1

consistent with the position reported by Lipunov et al. We note this position lies outside the Fermi LAT error circle.
We measure the following magnitudes, as compared to a nearby SDSS star:

filter |     mag (AB)     | time (days)
â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”â€”-
g      |  17.91 +- 0.07  |  0.444
r       |  17.56 +- 0.08  |  0.448
i       |  17.38 +- 0.08  |  0.440


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24688
SUBJECT: GRB 190530A: GWAC-F30 optical detection
DATE:    19/05/31 01:42:46 GMT
FROM:    Liping Xin at NAOC, SVOM  <xlp@nao.cas.cn>

L. P. Xin,  G. W. Li, R. S. Zhang,  T. C. Zheng, J. Wang,   J. Y. Wei,   Y. G. Yang, 
E. W. Liang,  X. G. Wang,   H. L. Li, X. H. Han,  X. M. Lu,  L. Huang,    H. B. Cai,   
Y. L. Qiu,  Y. Xu, Y.  J. Xiao, Y. T. Zheng,  C. Wu,   J. S. Deng,  D. W. Xu, 
D. Turpin, W. L. Dong, P. P. Zhang and Jirong Mao report:

We began to observe GRB 190530A (Fermi-GBM team, GCN 24676 ) with GWAC-F30cm telescope 
at 2019-05-30T12:48:46(UT), about 2.49 hour after the burst. GWAC-F30cm telescope is located at Xinglong
observatory, China. The field of view is about 1.9*1.9 sqr. deg. The coordinates  we used to make the 
observations was derived from  Biltzinger et al., (GCN 24677). Due to the low elevation of this source
at Xinglong observatory,  only seven R-band images were obtained. The exposure time for each frame
was 20 seconds. 

The afterglow was detected by stacking all the images. 
The coordinates is about RA=08:02:07.678  DEC=+35:28:47.14 J2000,
consistent with the position reported by Lipunov et al., GCN 24680. 
The magnitude was R=15.1mag, calibrated by the nearby USNO R2 magnitudes.

This message my be cited.


GRB_name: GRB190530A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24689
SUBJECT: GRB 190530A: Swift-XRT afterglow detection
DATE:    19/05/31 04:14:12 GMT
FROM:    Aaron Tohuvavohu at PSU/Swift  <auc444@psu.edu>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), A. Tohuvavohu (PSU), S.
J. LaPorte (PSU), J.A. Kennea (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester), A.P. Beardmore (U. Leicester), M.G. Bernadini
(INAF-OAB) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 190530A (Longo et al. GCN Circ. 24679),
collecting 3.1 ks of Photon Counting (PC) mode data between T0+33.8 ks
and T0+50.4 ks. 

Four uncatalogued X-ray sources are detected, of which one ("Source 5")
is above the RASS limit, and is therefore likely the GRB afterglow.
This source is coincident with the location of the optical counterpart
candidate reported by MASTER (Lipunov et al., GCN 24680). Using 2727 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 = 120.53242, +35.47947 which is equivalent
to:

RA (J2000): 08h 02m 07.78s
Dec(J2000): +35d 28' 46.1"

with an uncertainty of 1.4 arcsec (radius, 90% confidence). This
position is 11.3 arcmin from the Fermi/LAT position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.2 (+/-0.4).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.70 (+/-0.11). The
best-fitting absorption column is  1.1 (+0.4, -0.3) x 10^21 cm^-2, in
excess of the Galactic value of 5.1 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 3.6 x 10^-11 (4.1 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.1 (+0.4, -0.3) x 10^21 cm^-2
Galactic foreground: 5.1 x 10^20 cm^-2
Excess significance: 3.1 sigma
Photon index:      1.70 (+/-0.11)

If the light curve continues to decay with a power-law decay index of
2.2, the count rate at T+24 hours will be 0.13 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.7 x
10^-12 (5.5 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020893.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020893.

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


GRB_name: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24690
SUBJECT: GRB 190530A: COATLI Optical Detection of the Fading Afterglow
DATE:    19/05/31 06:41:22 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego
GonzÃ¡lez (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM),
Margarita Pereyra (UNAM), and Eleonora Troja (GSFC) report:

We observed the field of Fermi GBM/LAT GRB 190530A (Fermi GBM Team, GCN
Circ. 24676; Longo et al., GCN Circ. 24679) with the COATLI 50-cm
telescope and interim imager at the Observatorio AstronÃ³mico Nacional on
the Sierra de San Pedro MÃ¡rtir (http://coatli.astroscu.unam.mx) from
2019-05-31 03:33 to 06:27 (from 17.2 to 20.1 hours after the trigger),
obtaining a total of 8190 seconds of exposure in the w filter.

We detect the afterglow (Lipunov et al., GCN Circ. 24680; Melandri et
al., GCN Circ. 24689) at

  w = 18.18 +/- 0.01

During our observations, the afterglow fades with a power-law index of
-1.05 +/ 0.25.

Our w magnitudes are calibrated against the Pan-STARRS1 catalog, are on
an approximate AB system, and are not corrected for Galactic extinction
in the direction of the GRB.

We thank the COATLI technical team and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB190531A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24691
SUBJECT: GRB 190531A: Fermi GBM Final Real-time Localization
DATE:    19/05/31 07:40:41 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 07:29:11 UT on 31 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190531A (trigger 580980556.825258 / 190531312).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 21.1, Dec = 16.4 (J2000 degrees, equivalent to J2000 01h 24m, 16d 23'), with a statistical uncertainty of 2.2 degrees.

The angle from the Fermi LAT boresight is 57.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190531312/quicklook/glg_skymap_all_bn190531312.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190531312/quicklook/glg_healpix_all_bn190531312.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190531312/quicklook/glg_lc_medres34_bn190531312.gif


GRB_name: GRB190530A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24692
SUBJECT: GRB 190530A: Fermi GBM observation
DATE:    19/05/31 09:31:51 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:


"At 10:19:08.90 UT on 30 May 2019, the Fermi
Gamma-Ray Burst Monitor (GBM) triggered and located
GRB 190530A (trigger 580904353 / 190530430, GCN #24676),
which was also detected by AGILE-MCAL (GCN # 24678) and
Fermi-LAT (GCN # 24679).

The GBM light curve consists of multiple bright peaks
with a duration (T90) of about 18.4 s (50-300 keV).

The time-averaged spectrum from T0 to T0+20 s is
adequately fit by a Band function with Epeak = 900 +/- 10 keV,
alpha = -1.00 +/- 0.01, and beta = -3.64 +/- 0.12.

The event fluence (10-1000 keV) in this time interval
is (3.72 +/- 0.01)E-04 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+16.4 s
in the 10-1000 keV band is 160.5 +/- 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: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24693
SUBJECT: GRB 190530A: optical afterglow detection by 5 MASTER telescopes
DATE:    19/05/31 09:46:11 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov (Lomonosov MSU), D.Svinkin (Ioffe Institute),
J.Greiner (MPG, Germany),
D.Vlasenko, O.Gress, I.Gorbunov, E.Gorbovskoy, A.Kuznetsov, V.Kornilov, V.Vladimirov,
P.Balanutsa, D.Zimnukhov, F.Balakin, N.Tiurina, A. Chasovnikov, V.Topolev, 
V.Senik, D.Kuvshinov
(Lomonosov Moscow State University, SAI, Physics Department),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),

O. Gress, N.M. Budnev, O.Ershova, S.Yazev (Applied Physics Institute, Irkutsk State University),

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

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix 
Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, 
SJNU)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

D. Buckley (South African Astronomical Observatory),


MASTER Global Robotic Net (Lipunov et al., 2010, Advances in Astronomy,vol.2010, 30L  (http://observ.pereplet.ru)
observed Fermi GRB 190530A (GBM team GCN 24676, BALROG Biltzinger et al.GCN 24677, LAT Longo et al. GCN 24679 and IPN localization;
gamma-ray transient also detected by AGILE 8s later Lecarelli et al. GCN 24678, Verrecchia et al. GCN 24683)
in MASTER-Amur, MASTER-Tunka, MASTER-SAAO, MASTER-Kislovodsk, MASTER-Tavrida, MASTER-IAC
(the order in accordance with sunset).

MASTER auto-detection system discovered  MASTER OT J080207.73+352847.7 = AT 2019gdw
(https://wis-tns.weizmann.ac.il/object/2019gdw ) at 
(RA,Dec2000)=08h 02m 07.73s +35d 28m 47.7s( Lipunov et al. GCN24680)

MASTER-Amur robotic telescope automatically was pointed to the Fermi GRB190530A 
BALROG localization at 2019-05-30 14:34:09
(error-box altitude = 13 (and go down), sun_alt=-17
very cloudy weather at sunset) with 
automatic photometry m_OT ~ 14.8

MASTER-Tunka robotic telescope automatically was pointed to the GRB190530A
at 2019-05-30 14:43:13UT (error_box_alt=26deg., sun_alt=-10deg.),
automatic photometry m_OT ~ 16.5

MASTER-SAAO robotic telescope automatically was pointed to the GRB190530A
at 2019-05-30 16:34:41UT (very cloudy all horizont, error-box_alt=13.5 and go down, sun_alt=-11) 
mlim=14.5

MASTER-Kislovodsk robotic telescope automatically was pointed to the GRB190530A
at 2019-05-30 18:12:10 (sun altitute= -16deg., alert_altitute=23deg.)
automatic photometry m_OT~16.7

MASTER-Tavrida robotic telescope automatically was pointed to the GRB190530A
at 2019-05-30 2019-05-30 18:12:17
(sun altitute= -8deg., alert_altitute=34deg.)
automatic photometry m_OT~16.7

MASTER-IAC  robotic telescope automatically was pointed to the GRB190530A
at 2019-05-30  20:50:32UT
(sun altitute=-11 deg., alert_altitute=36 deg.)
automatic photometry unfiltered m_OT~17.4

The covered map and OT place is available at
https://master.sai.msu.ru/site/master2/event.php?id=1034468


Observation and reduction will be continued.
The message may be cited.


GRB_name: GRB190530A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24694
SUBJECT: GRB 190530A: AstroSat CZTI detection
DATE:    19/05/31 14:55:41 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

P. Ghumatkar, V. Sharma, D. Bhattacharya, T. Khanam and A. Vibhute (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data showed the detection of a long GRB 190530A, which was also detected by AGILE-MCAL (Lucarelli F. et al., GCN # 24678), Fermi-LAT (Longo F. et al., GCN # 24679), AGILE/GRID (Verrecchia F. et al., GCN # 24683), Swift-XRT (Melandri A. et al., GCN # 24689) and Fermi GBM (Bissaldi E. et al., GCN # 24692).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple pulses of emission with the strongest peak at 10:19:25.5 UT. The measured peak count rate associated with the burst is 2745 cts/s above the background in the combined data of four quadrants, with a total of 23800 cts. The local mean background count rate was 486 cts/s. Using cumulative rates, we measure a T90 of 23.9 s. In preliminary analysis, we find that 1931 Compton events are associated with this event.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.


GRB_name: GRB190531B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24695
SUBJECT: GRB 190531B: Fermi GBM Final Real-time Localization
DATE:    19/05/31 20:21:23 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 20:10:12 UT on 31 May 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190531B (trigger 581026217.141598 / 190531840).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 20.2, Dec = -39.4 (J2000 degrees, equivalent to J2000 01h 20m, -39d 23'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 22.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190531840/quicklook/glg_skymap_all_bn190531840.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190531840/quicklook/glg_healpix_all_bn190531840.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190531840/quicklook/glg_lc_medres34_bn190531840.gif


GRB_name: GRB190531A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24696
SUBJECT: Fermi Trigger 581026217 / GRB 190531840 / GRB190531A: BALROG localization
DATE:    19/05/31 20:44:35 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
581026217 at 20:10:12 on 31 May 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 27.9+/-0.8 deg
Decl.(2000.0) = -40.8+/-0.6 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190531840/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190531840/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190531840/json

                        


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24697
SUBJECT: GRB 190530A: Xinglong 2.16m optical observation
DATE:    19/05/31 21:29:02 GMT
FROM:    Liping Xin at NAOC, SVOM  <xlp@nao.cas.cn>

L. P. Xin,  J. B. Zhang, G. W. Li,  R. S. Zhang,  T. C. Zheng, J. Wang,  
J. Y. Wei,   Y. G. Yang, E. W. Liang,  X. G. Wang,   H. L. Li, X. H. Han,  
X. M. Lu,  L. Huang,    H. B. Cai,   Y. L. Qiu,  Y. Xu, Y.  J. Xiao, 
Y. T. Zheng,  C. Wu,   J. S. Deng,  D. W. Xu,  D. Turpin, 
W. L. Dong, P. P. Zhang and Jirong Mao report:

We observed Fermi GRB 190530A  (Fermi GBM Team, GCN Circ. 24676; 
Longo et al., GCN Circ. 24679)  using the  Xinglong-2.16m equipped with 
the BFOSC camera. Observations were carried out from 12:49:45 to 
13:40:10 UT on 2019-05-31, 62*50sec R band images were obtained.

The optical afterglow (Lipunov et al., GCN 24680, 24693; Kann et al., GCN Circ 24684; 
Melandri et al., GCN Circ. 24689; Heintz et al., GCN Circ 24686; Lzzo et al., GCN Circ 24687; 
Xin et al., GCN Circ 24688; Watson et al., GCN Circ.24690) was clearly detected in our 
stacked image with a magnitude of R=19.63+/-0.1 mag at the mid time of about 1.12 days 
after the burst, calibrated with nearby SDSS stars


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24698
SUBJECT: GRB 190530A: AbAO optical observations
DATE:    19/05/31 21:55:33 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), V.R. 
Ayvazian (AbAO), E. Mazaeva (IKI), A. Volnova  (IKI)   report on behalf 
of larger IKI GRB FuN collaboration:

We observed the  optical afterglow (Lipunov et al., GCN 24680, 24693; 
Kann et al., GCN 24684; Melandri et al., GCN  24689; Heintz et al., GCN 
24686; Lzzo et al., GCN  24687; Xin et al., GCN   24688; Watson et al., 
GCN  24690; Xin et al., GCN 24697)  of the Fermi GBM, LAT GRB 190530A 
(Fermi GBM Team, GCN  24676; Longo et al., GCN   24679) with AS-32 
(0.7m) telescope of Abastumani Observatory starting on May  31 (UT) 
17:44:00. Preliminary photometry of the afterglow is following.

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

2019-05-31  17:44:00 1.32171 R     19*60 18.5  0.1  19.5

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

USNO-B1.0_id R2
1255-0157926 13.35
1254-0159410 12.63
1255-0157793 13.56


GRB_name: GRB190531B
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24699
SUBJECT: GRB 190531B: name correction re. GCN 24696
DATE:    19/05/31 22:41:40 GMT
FROM:    Jochen Greiner at MPI  <jcg@mpe.mpg.de>

F. Kunzweiler & J. Greiner (both MPE Garching)

GCN 24696 wrongly named Fermi trigger 581026217 / GRB 190531840 
as GRB 190531A, but it should be GRB 190531B.

We apologize for any confusion this might have caused.


GRB_name: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24700
SUBJECT: GRB 190530A: Steep afterglow decay found by OSN
DATE:    19/05/31 23:13:05 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

D. A. Kann, L. Izzo (both HETH/IAA-CSIC), A. de Ugarte Postigo 
(HETH/IAA-CSIC, DARK/NBI), M. Blazek, C. C. Thoene, K. Bensch (all 
HETH/IAA-CSIC), and V. Casanova (IAA-CSIC) report:

We observed the afterglow position (Lipunov et al., GCN 24680) of the 
extremely bright GRB 190530A (GBM detection and localization: Fermi GBM 
team, GCN 24676, Biltzinger et al., GCN 24677; Fermi-LAT localization: 
Longo et al., GCN 24679; Agile-MCAL/GRID detections: Lucarelli et al., 
GCN 24678, Verecchia et al., GCN 24683) a second time with the 1.5-m 
telescope of the Sierra Nevada Observatory (OSN), Spain. The afterglow 
is now only marginally detected in single frames, so we stack 7 x 120 s 
images.

We measure the following AB magnitude:

Rc = 20.60  +- 0.15 mag at 1.44509 days after the GRB.

The magnitude was derived against 1 nearby star from the SDSS catalog, 
using the transformation equations of Lupton (2005), and transformed 
back into AB mag.

This magnitude is significantly fainter than expected from an 
extrapolation of the decay from the first day, indicating a break in the 
light curve must have occurred. Using other observations (Lipunov et 
al., GCN 24680, GCN 24693; Kann et al., GCN 24684; Heintz et al., GCN 
24686; Izzo et al., GCN 24687; Xin et al., GCN 24688; Watson et al., GCN 
24690; Xin et al., GCN 24697) we find the afterglow is described by a 
broken power-law with pre-break decay slope alpha_1 = 1.21 +/- 0.07, 
post-break decay slope alpha_2 = 3.75 +/- 0.40, and break time t_b = 
0.78 +/- 0.06 days.

The steeper slope mentioned by Watson et al. (GCN 24690) may indicate 
the break was occurring during the COATLI observations. We note the 
magnitude given by Belkin et al. (GCN 2469 is significantly too bright, 
this may stem from their use of USNO stars as standard stars.

The post-break decay slope is extremely steep and generally not expected 
from the forward shock model and a typical electron energy distribution. 
Further observations are highly encouraged.


GRB_name: GRB190531B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24701
SUBJECT: GRB 190531B: Fermi-LAT detection
DATE:    19/06/01 01:02:55 GMT
FROM:    Magnus Axelsson at Stockholm U.  <magaxe@kth.se>

M. Axelsson (KTH and Stockholm Univ.), M. Arimoto (Kanazawa Univ.), D. Kocevski (NASA/MSFC) and F. Longo (Univ. and INFN Trieste) report on behalf of the Fermi-LAT team:

On May 31, 2019, Fermi-LAT detected high-energy emission from GRB 190531B, which was also detected by Fermi-GBM (trigger 581026217 / 190531840; GCN 24695).

The best LAT on-ground location is found to be

RA, Dec 24.37, -41.97 (degrees, J2000)

with an error radius of 0.11 deg (90% containment, statistical error only).
This was 25 deg from the LAT boresight at the time of the GBM trigger:

T0 =  20:10:12.14 UT.

The data from the Fermi-LAT show a significant increase in the event rate after the GBM trigger that is spatially and temporally correlated with the GBM emission with high significance.

The photon flux above 100 MeV in the time interval 0-700 s after the GBM trigger is 8.9e-6 ph/cm2/s. The highest-energy photon in this interval is a 7.0 GeV event observed at T0+325s.

The estimated photon index above 100 MeV is -2.1 +/- 0.2.

The Fermi-LAT point of contact for this burst is Francesco Longo (Francesco.Longo@ts.infn.it<mailto:Francesco.Longo@ts.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: GRB190531B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24702
SUBJECT: GRB 190531B: Swift ToO observations
DATE:    19/06/01 01:24:19 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 190531B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020895

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: GRB190530A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24703
SUBJECT: GRB 190530A: Swift/UVOT Detection
DATE:    19/06/01 03:10:41 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 190530A
33.8 ks after the LAT trigger (GCN Circ. 24676). A fading source consistent
with the optical counterpart first reported by Lipunov et al. (GCN Circ.
24680) is detected in the initial UVOT exposures.

The preliminary UVOT position is:
   RA  (J2000) =  08:02:07.70 = 120.53209 (deg.)
   Dec (J2000) = +35:28:46.8  =  35.47968 (deg.)
with an estimated uncertainty of 0.49 arc sec. (radius, 90% confidence).

Preliminary detections 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

v                56532        56734          199         18.49 +/- 0.23
b                38334        38490          153         18.06 +/- 0.09
u                38132        38329          194         17.09 +/- 0.06
w1               37734        38128          388         16.89 +/- 0.06
w2               44276        44610          329         17.39 +/- 0.08

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190531B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24705
SUBJECT: GRB 190531B: Fermi GBM observations
DATE:    19/06/01 03:39:22 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres and C. Meegan (both UAH) report on behalf of the Fermi GBM Team:

"At 20:10:12.14 UT on 31 May 2019, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 190531B (trigger 581026217 / 190531840, GCN
#24695), which was also detected by Fermi-LAT (GCN # 24701).

The GBM light curve consists of multiple peaks with a duration (T90) of
about 38.4 s (50-300 keV).

The time-averaged spectrum from T0 to T0+44.4 s is best fit by a Band
function with Epeak = 473 +/- 14 keV, alpha = -0.79 +/- 0.01, and beta =
-2.33 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is (9.91 +/-
0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from
T0+31.2 s in the 10-1000 keV band is 27.7 +/- 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: GRB190531B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24706
SUBJECT: GRB 190531B: Swift-XRT afterglow detection
DATE:    19/06/01 07:46:50 GMT
FROM:    Aaron Tohuvavohu at PSU/Swift  <auc444@psu.edu>

P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea (PSU), B.
Sbarufatti (INAF-OAB/PSU), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), M.G. Bernadini (INAF-OAB), E. Ambrosi  (INAF-IASFPA) , 
A. Tohuvavohu (PSU) and P.A. Evans (U. Leicester) report on behalf of
the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/LAT-detected burst GRB 190531B (Axelsson et al. GCN Circ. 24701),
collecting 5.0 ks of Photon Counting (PC) mode data between T0+18.2 ks
and T0+29.7 ks. 

Eleven uncatalogued X-ray sources are detected, of which one ("Source
8") is above the RASS limit, and is therefore likely the GRB afterglow.
Using 1291 s of PC mode data and 1 UVOT image, we find an enhanced XRT
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 24.29620, -41.95841 which is
equivalent to:

RA (J2000): 01h 37m 11.09s
Dec(J2000): -41d 57' 30.3"

with an uncertainty of 1.6 arcsec (radius, 90% confidence). This
position is 3.4 arcmin from the Fermi/LAT position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.0 (+/-0.3).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.20 (+0.15, -0.14). The
best-fitting absorption column is  9.1 (+1.2, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 1.8 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 4.2 x 10^-11 (9.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.1 (+1.2, -1.1) x 10^21 cm^-2
Galactic foreground: 1.8 x 10^20 cm^-2
Excess significance: 12.8 sigma
Photon index:      2.20 (+0.15, -0.14)

If the light curve continues to decay with a power-law decay index of
1.0, the count rate at T+24 hours will be 0.14 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 5.9 x
10^-12 (1.3 x 10^-11) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020895/Source8.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020895.

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


GRB_name: GRB190531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24707
SUBJECT: GRB 190531B: MASTER optical observation
DATE:    19/06/01 10:06:41 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, N.Tiurina, A.Kuznetsov, I.Gorbunov, 
V.Vladimirov, P.Balanutsa, D.Vlasenko, D.Zimnukhov, F.Balakin,A. Chasovnikov,
V.Topolev, V.Senik, D.Kuvshinov(Lomonosov Moscow State University, SAI, Physics Department),

D. Buckley (South African Astronomical Observatory),

R. Podesta, C. Lopez, C.Francile, F. Podesta (Observatorio Astronomico Felix Aguilar OAFA, San Juan National University),

H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE, SJNU)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres (The Instituto de Astrofisica de Canarias),

O. Gress, N.M. Budnev, O.Ershova, S.Yazev (Applied Physics Institute, Irkutsk State University),

V. Yurkov, A. Gabovich, Yu. Sergienko, D. Kobcev (Blagoveschensk Educational State University),

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

MASTER Global Robotic Net (Lipunov et al., 2010, Advances in Astronomy,vol.2010, 30L  (http://observ.pereplet.ru)
observed Fermi GRB 190531B
(Ttrig=2019-05-31 20:10:12UT, GBM team GCN24695, Veres et al. GCN 24705;
BALROG localization RA,Dec(2000) = 27.9(+/-0.8d) -40.8(+/-0.6) Kunzweiler et al. GCN 24696, GCN 24699,
LAT localization RA,Dec= 24.37, -41.97 +-0.11d(90%)  Axelsson et al. GCN24701,
Swift XRT afterglow 01h 37m 11.09s -41d 57' 30.3"  +-1.6 arcsec(90%) D'Avanzo et al. GCN24706, Evans et al. 24702 )

At alert time
MASTER-SAAO:   Error-Box_altitude=-15d, Sun_alt=-57d.
MASTER-OAFA:   Error-Box_altitude=+15d, Sun_alt=+15d

MASTER-SAAO robotic telescope (located in South African Astronomical Observatory)
was pointed to the  GRB190531A 4934 sec after notice time and 20321 sec 
after trigger time at 2019-06-01 01:48:53 UT .
Error-box_alt=21deg, sun_alt=-47deg.
There is no OT at Swift XRT position with unfiltered mlim=20.6m

MASTER-OAFA robotic telescope (located in Argentina)
was pointed to the  GRB190531A at 2019-06-01 08:55:19UT
Error-box_alt=34deg, sun_alt=-32deg.
There is no OT at Swift XRT position with unfiltered mlim=20.0m


Reduction will be continued.
The message may be cited.


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24708
SUBJECT: GRB 190530A: SAO RAS optical observations
DATE:    19/06/01 12:21:26 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

Moskvitin A. S. and Uklein R. I. (SAO RAS)
report on behalf of larger collaboration.

We observed the field of the GRB 190530A (Fermi GBM Team, GCNC 24676;
Longo et al., GCNC 24679) with the 1-m telescope of SAO RAS
equipped with the MMPP (Multi-Mode Photometer-Polarimeter)
and UBVRcIc filters on May 31 / June 1 night.

We obtained 11 x 300 sec. frames in Rc band.
The OT (Lipunov et al., GCNC 24680; Kann et al., GCNC 24684;
Heintz et al., GCNC 24686; Izzo et al., GCNC 24687;
Xin et al., GCNC 24688; Watson et al., GCNC 24690;
Lipunov et al., GCNC 24693; Xin et al., GCNC 24697;
Belkin et al.,  GCNC 24698; Kann et al., GCNC 24700;
Siegel, GCNC 24703) is clearly detected in our stacked image.
The OT brightness is R(AB) = 19.39 +/- 0.05 (T_mid - T0 = 1.353 days).

The OT magnitude was calculated against the nearby SDSS stars
whose magnitudes were transformed with the equations of Lupton (2005).
The magnitude of OT was converted to AB system
and was not corrected for the Galactic extinction.


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24709
SUBJECT: GRB 190530A: Konkoly optical observations of the afterglow
DATE:    19/06/01 18:26:08 GMT
FROM:    Jozsef Vinko at Konkoly Observatory  <vinko@konkoly.hu>

J. Vinko, R. Szakats, A. Pal, L. Kriskovics, A. Ordasi, K. Sarneczky
(MTA CSFK Konkoly Observatory) report:

The optical afterglow (Lipunov et al., GCN 24680; Kann et al., GCN 24684; Heintz et al., GCN 24686;
Izzo et al., GCN 24687; Xin et al., GCN 24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693;
Xin et al., GCN 24697; Belkin et al.,  GCN 24698; Kann et al., GCN 24700; Siegel, GCN 24703;
Moskvitin and Uklein, GCN 24708) of the bright GRB 190530A (Fermi GBM team, GCN 24676, Biltzinger et al.,
GCN 24677;  Longo et al., GCN 24679; Lucarelli et al.,GCN 24678, Verecchia et al., GCN 24683)
is marginally detected on the stacked Sloan-r band CCD frames (total exposure time 45 min)
taken with the 0.8m RC80 telescope at Konkoly Observatory, Piszkesteto (Hungary)
on 2019-05-31.35 UT, 1.42 day after the burst.
                          
Aperture photometry on the stacked frame, tied to PS1 r-band data of 19 local comparison
stars resulted in the following AB magnitude for the transient:
                          
r_PS1 (AB) = 19.86 +/- 0.37 mag

This is consistent with R-band brightness (~19.39 +/- 0.05 AB-mag at 1.353 days after burst) reported by
Moskvitin and Uklein (GCN 24708), but significantly brighter than the one measured by Kann
et al. (GCN 24700, Rc ~ 20.60 +/- 0.15 AB-mag at 1.44509 day after burst).

Further monitoring of this interesting transient is encouraged.


GRB_name: GRB190531B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24711
SUBJECT: GRB 190531B: VLT optical upper limit
DATE:    19/06/01 20:38:26 GMT
FROM:    Jure Japelj at API,U of Amsterdam  <japelj.jure@gmail.com>

J. Japelj (U. Amsterdam), A. Rossi (INAF-OAS), D. B. Malesani
(DTU Space), K. E. Heintz (Univ. Iceland), G. Pugliese, L. Kaper
(U. Amsterdam) report on behalf of the Stargate collaboration:

We observed the field of GRB 190531B (Fermi GBM team, GCN 24695;
Kunzweiler et al., GCN 24696; Axelsson et al., GCN 24701) with the ESO VLT
UT2 (Kueyen), using the X-shooter acquisition camera. A 3x30 s exposure
with the SDSS r filter was taken at approximate time 2019 June 1.39 UT
(0.55 days after GRB).

We do not detect any new object within the error region of the detected
X-ray afterglow (D'Avanzo et al., GCN 24706), down to a 3-sigma
limiting magnitude r > 23 AB (calibrated against nearby star at position
RA=01:37:12.696, Dec=-41:57:36.702). The closest source to the XRT error
circle is at RA=01:37:11.37, Dec=-41:57:30.73, which is 3.1 arcsec away
from the XRT location, and is thus unlikely to be related to the GRB.

We acknowledge excellent support from the observing team in Paranal,
in particular Alex Correa, Florian Rodler and Pascale Hibon.


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24712
SUBJECT: GRB 190530A: Mondy and AbAO optical observations
DATE:    19/06/02 09:53:20 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI),  E. Klunko (ISTP), R. Ya. Inasaridze (AbAO), A. 
Pozanenko (IKI), V.R. Ayvazian (AbAO), E. Mazaeva (IKI), A. Volnova 
(IKI) report on behalf of IKI GRB FuN collaboration:

We continue observations the  optical afterglow (Lipunov et al., GCN 
24680, 24693 and also e.g. Kann et al., GCN 24684; Melandri et al., GCN 
24689; Heintz et al., GCN 24686; Lzzo et al., GCN  24687; Xin et al., 
GCN   24688; Watson et al., GCN  24690; Xin et al., GCN 24697)  of the 
Fermi GRB 190530A (Fermi GBM Team, GCN  24676; Longo et al., GCN 
24679) with   AZT-33IK telescope of Sayan observatory (Mondy) and AS-32 
(0.7m) telescope of Abastumani Observatory. The afterglow is clearly 
visible in stacked images. Preliminary photometry of the afterglow is 
following.

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

2019-06-01  15:35:00 2.23638  R    29*60 19.62  0.07  21.2
2019-06-01  17:38:57 2.31769  R    30*60 19.70  0.14  20.6

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

USNO-B1.0_id R2
1255-0157926 13.35
1254-0159410 12.63
1255-0157793 13.56

The photometry might be influenced by nearby optical source presented in 
    Pan-STARRS DR1 catalog (ID 150571205309266249) mentioned in (Lipunov 
et al., GCN 24680).


GRB_name: GRB190531B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24713
SUBJECT: GRB 190531B: Insight-HXMT/HE detection
DATE:    19/06/02 15:16:57 GMT
FROM:    QiBin Yi at IHEP, HXMT  <yiqb@ihep.ac.cn>

Q. B. Yi, S. Xiao, Q. Luo, C. Cai, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-05-31T20:10:12.00 (T0), Insight-HXMT/HE detected 
GRB 190531B (trigger ID: HEB190531840) in a routine search of the data, 
which was also triggered by Fermi/GBM (GCN #24695) and Fermi/LAT 
(GCN #24701). 

The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 27.82 s measured from T0+7.93 s. 
The 1-ms peak rate, measured from T0+31.40 s, is 13079 cnts/sec. 
The total counts from this burst is 91598 counts. 
URL_LC: http://www.hxmt.org/images/GRB/HEB190531840_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.


GRB_name: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24714
SUBJECT: GRB 190530A: Insight-HXMT/HE detection
DATE:    19/06/02 15:17:47 GMT
FROM:    QiBin Yi at IHEP, HXMT  <yiqb@ihep.ac.cn>

Q. B. Yi, S. Xiao, Q. Luo, C. Cai, C. K. Li,
X. B. Li, G. Li, J. Y. Liao, S. L. Xiong, 
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, X. F. Lu,
A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, 
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:

At 2019-05-30T10:19:08.90 (T0), Insight-HXMT/HE detected 
GRB 190530A (trigger ID: HEB190530429) in a routine search of the data, 
which was also triggered by Fermi/GBM (GCN #24676), Fermi/LAT 
(GCN #24679), and AGILE/MCAL(GCN #24678). 

The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 20.31 s measured from T0+2.11 s. 
The 1-ms peak rate, measured from T0+10.52 s, is 18182 cnts/sec. 
The total counts from this burst is 214189 counts. 
Some part of the Insight-HXMT/HE light curve suffers data saturation 
due to the extreme brightness of this burst.
URL_LC: http://www.hxmt.org/images/GRB/HEB190530429_lc.jpg 

All measurements above are made with the CsI detectors operating in the 
regular mode with the energy range of about 80-800 keV (deposited energy). 
Only gamma-rays with energy greater than about 200 keV can penetrate 
the spacecraft and leave signals in the CsI detectors installed inside 
of the telescope. 

Insight-HXMT is the first Chinese space X-ray telescope, which was 
funded jointly by the China National Space Administration (CNSA) and 
the Chinese Academy of Sciences (CAS). 
More information about it could be found at: 
http://www.hxmt.org.


GRB_name: GRB190530A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24715
SUBJECT: Konus-Wind observation of extremely bright GRB 190530A
DATE:    19/06/02 15:18:51 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The extremely bright, long GRB 190530A
(Fermi GBM detection: GCN 24676,24692; AGILE-MCAL detection: GCN 24679;
Fermi-LAT detection: GCN 24679; AGILE/GRID analysis: GCN 24683;
AstroSat CZTI detection: GCN 24694) triggered Konus-Wind (KW)
at T0=37146.000 s UT (10:19:06.000).

The light curve of the burst shows a bright, multi-peaked pulse
with a total duration of ~55s, followed by a weaker and softer
emission tail visible until ~T0+150 s.
The emission in the bright phase of the burst is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190530_T37146/

As observed by Konus-Wind, the burst had
a fluence of (5.57 Â± 0.15)x10^-4 erg/cm2 and
a 64-ms peak energy flux, measured from T0+14.912,
of (1.59 Â± 0.10)x10^-4 erg/cm2 (both in the 20 keV - 10 MeV
energy range).

The time-integrated spectrum (measured from T0 to T0+44.228 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.03 (-0.02,+0.02),
the high energy photon index beta = -3.03 (-0.36,+0.22),
the peak energy Ep = 848 (-33,+44) keV,
chi2 = 140/96 dof.

The spectrum near the peak count rate (measured from T0+14.848 s
to T0+15.104 s) is best fit in the 20 keV - 16 MeV range
by a cutoff power-law (CPL) function with the following model
parameters: the photon index alpha = -0.41(-0.07,+0.07),
and the peak energy Ep = 1176(-46,+47) keV, chi2 = 55/60 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and an upper limit on beta of -3.2.

Assuming an upper limit on the burst redshift z<2.2 (Heintz et al.,
GCN 24686) and a standard cosmology with H_0 = 70 km/s/Mpc,
Omega_M = 0.30, and Omega_Lambda = 0.70, we estimate the following
upper limits on the GRB rest-frame energetics: the isotropic energy
release E_iso < 6.4x10^54 erg and the peak luminosity L_iso < 5.8x10^54
erg/s (both in the bolometric 1-10000 keV range).
Location of GRB 190530A in rest-frame hardness-intensity planes,
along with 'Amati' and 'Yonetoku' relations for the KW sample of
GRBs with known redshifts (Tsvetkova et al., ApJ 850 161, 2017), can be
found at http://www.ioffe.ru/LEA/GRBs/GRB190530_T37146/GRB190530A.pdf

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB190530A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24729
SUBJECT: GRB 190530A: R-band observation from HCT
DATE:    19/06/03 13:53:56 GMT
FROM:    Brajesh Kumar at Indian Inst. of Astrophysics  <brajesh.kumar@iiap.res.in>

Brajesh Kumar (IIA), Avinash Singh (IIA), G. C. Anupama (IIA), D. K. 
Sahu (IIA) and S. B. Pandey (ARIES)

We observed the field of GRB 190530A (Fermi GBM team, GCN 24676, 
Biltzinger et al., GCN 24677; Lucarelli et al.,GCN 24678, Longo et al., 
GCN 24679; Verecchia et al., GCN 24683) with the 2-m Himalayan Chandra 
Telescope (HCT) located at the Indian Astronomical Observatory, Hanle, 
India. The observations started on 2019-06-02 14:50:43 UT i.e. around 
3.19 days from Fermi GBM trigger (GCN 24676).

The optical afterglow (Lipunov et al., GCN 24680; Kann et al., GCN 
24684; Heintz et al., GCN 24686; Izzo et al., GCN 24687; Xin et al., GCN 
24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693; Xin et al., 
GCN 24697; Belkin et al., GCN 24698; Kann et al., GCN 24700; Siegel, GCN 
24703; Moskvitin and Uklein, GCN 24708; Vinko et al., GCN 24709; Belkin 
et al., GCN 24712) is detectable in our stacked image taken in Bessell 
R-band with a total integration time of 15 min. The preliminary 
magnitude of the OT is estimated as 21.3 +/- 0.3 mag.

These magnitudes were calibrated using the field stars from the 
USNO-B1.0 catalogue.

We thank the observing staff at IAO and CREST for helping with the 
observations.


GRB_name: GRB190531B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24730
SUBJECT: Konus-Wind observation of GRB 190531B
DATE:    19/06/03 17:52:24 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A. Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 190531B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 24695;
Fermi-GBM observations: Veres and Meegan, GCN Circ. 24705;
Fermi-LAT detection: Axelsson et al., GCN Circ. 24701;
Insight-HXMT/HE detection: Yi et al., GCN Circ. 24713)
triggered Konus-Wind at T0=72616.175 s UT (20:10:16.175).

The burst light curve shows a multipeaked structure
which starts at ~T0-38 s and has a total duration of ~110 s.
The emission is seen up to ~5 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.51(-0.15,+0.16)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+17.648 s,
of 1.96(-0.30,+0.30)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+83.712 s)
is best fit in the 20 keV - 5 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.73(-0.08,+0.08),
the high energy photon index beta = -2.25(-0.21,+0.14),
the peak energy Ep = 364(-34,+40) keV
(chi2 = 63/72 dof).

The spectrum near the maximum count rate
(measured from T0+15.616 to T0+19.456 s)
is best fit in the 20 keV - 7 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.60(-0.08,+0.09),
the high energy photon index beta = -2.64(-0.46,+0.26),
the peak energy Ep = 520(-53,+55) keV
(chi2 = 87/77 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB190531_T72616/

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


GRB_name: GRB190531B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24731
SUBJECT: GRB 190531B: Swift/UVOT Upper Limits
DATE:    19/06/03 19:12:44 GMT
FROM:    Kira Simpson at PSU  <kira.simpson1984@gmail.com>

GRB 190531B: Swift/UVOT Upper Limits

K. K. Simpson (PSU)
reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190531B
18175 s after the LAT trigger (Axelsson et al., GCN Circ. 24701).
No optical afterglow consistent with the XRT position
(D'Avanzo et al., GCN Circ. 24706)
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

b                18661        24137          365         >20.5
u                18497        29702          551         >21.1
w1               18175        29509         1132         >20.7
m2               19630        25766          972         >20.9
w2               18826        24990         1459         >21.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB190603A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24732
SUBJECT: GRB 190603A: Fermi GBM Final Real-time Localization
DATE:    19/06/03 19:16:10 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 LONG GRB

At 19:04:25 UT on 3 Jun 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190603A (trigger 581281470.98357 / 190603795).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 20.1, Dec = 40.9 (J2000 degrees, equivalent to J2000 01h 20m, 40d 53'), with a statistical uncertainty of 5.9 degrees.

The angle from the Fermi LAT boresight is 57.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190603795/quicklook/glg_skymap_all_bn190603795.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190603795/quicklook/glg_healpix_all_bn190603795.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190603795/quicklook/glg_lc_medres34_bn190603795.gif


GRB_name: GRB190531B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24738
SUBJECT: GRB 190531B: CALET Gamma-Ray Burst Monitor detection
DATE:    19/06/04 08:09:40 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

Y. Shimizu (Kanagawa U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
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 190531B (Fermi-LAT detection: Axelsson et al.,GCN Circ. 24701;
Fermi-GBM observations: Veres and Meegan, GCN Circ. 24705;
Insight-HXMT/HE detection: Yi et al., GCN Circ. 24713;
Konus-Wind observation: Svinkin et al., GCN Circ. 24730)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 20:10:20.034 UTC
on 31 May 2019. The burst signal was seen by all CGBM detectors.
No real-time CGBM GCN notice was distributed about this trigger because
the real-time communication from the ISS was off (loss of signal).

The burst light curve shows a multi-peaked emission episode which starts
at T-9.7 sec, peaks at 14.5 sec and ends at T+74.5 sec.
The T90 and T50 durations measured by the SGM data are 36.8 +- 20.0 sec
and 13.5 +- 0.9 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1243368627/

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


GRB_name: GRB190604A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24739
SUBJECT: GRB 190604A: Fermi GBM Final Real-time Localization
DATE:    19/06/04 10:54:11 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 10:42:37 UT on 4 Jun 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 190604A (trigger 581337762.053602 / 190604446).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 342.5, Dec = 46.4 (J2000 degrees, equivalent to J2000 22h 49m, 46d 23'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 71.0 degrees.

The skymap can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190604446/quicklook/glg_skymap_all_bn190604446.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190604446/quicklook/glg_healpix_all_bn190604446.fit

The GBM light curve can be found here:
http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn190604446/quicklook/glg_lc_medres34_bn190604446.gif


GRB_name: GRB190604A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24740
SUBJECT: GRB190604A: BALROG localization (Fermi Trigger 581337762 / GRB 190604446)
DATE:    19/06/04 14:18:58 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
581337762 at 10:42:37 on 04 June 2019 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 (1 sigma statistical errors) is:
RA(2000.0) = 341.1+/-1.1 deg
Decl.(2000.0) = 44.4+/-1.0 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB190604446/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB190604446/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB190604446/json

                        


GRB_name: GRB190604B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24742
SUBJECT: GRB 190604B: Swift detection of a burst
DATE:    19/06/04 15:16:35 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K. L. Page (U Leicester), S. D. Barthelmy (GSFC), J.D. Gropp (PSU),
N. J. Klingler (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), D. M. Palmer (LANL),
B. Sbarufatti (PSU), M. H. Siegel (PSU), K. K. Simpson (PSU) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 14:57:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 190604B (trigger=906654).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 297.587, -32.932 which is 
   RA(J2000) = 19h 50m 21s
   Dec(J2000) = -32d 55' 56"
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 250 sec, with two major peaks at 
~T0 and ~T+155 s. The peak count rate was ~4000 counts/sec (15-350 keV), 
at ~155 sec after the trigger. 

The XRT began observing the field at 14:59:12.5 UT, 116.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright, variable
uncatalogued X-ray source located at RA, Dec 297.53804, -32.97663 which
is equivalent to:
   RA(J2000)  = 19h 50m 09.13s
   Dec(J2000) = -32d 58' 35.9"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 218 arcseconds from the BAT onboard position. This position
may be improved as more data are received; the latest position is
available at http://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 1.36
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 0.1 s image was 1.11e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 126 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
0.14. 

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: GRB190604B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24743
SUBJECT: GRB 190604B: Prompt enhanced Swift-XRT position
DATE:    19/06/04 16:01:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using  promptly downlinked XRT event data for GRB 190604B, we find an
enhanced XRT position of the afterglow: RA, Dec: 297.5413, -32.9782
which is equivalent to:
   RA (J2000)  = 19 50 09.92
   Dec (J2000) = -32 58 41.4
with an uncertainty of 2.0 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/906654.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

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


GRB_name: GRB190530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24745
SUBJECT: GRB190530A: Photometric follow-up with GROWTH-India telescope
DATE:    19/06/04 18:04:50 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>

D. Nandi, Abhinand V, H. Kumar, M. Khandagale, V. Bhalerao(IITB), G. C.
Anupama, J. Stanzin (IIA) report on behalf of the GROWTH collaboration:

We observed the field of GRB190530A reported by Fermi GBM Team (GCN 24676)
at 2019-06-01.635 and 2019-06-02.685 UT with the 0.7m GROWTH-India
telescope. The images were taken in r filter. We detect a very faint source
at position Ra: 08h 02m 07.73s, Dec: +35d 28m 47.7s. Photometric results
obtained are as follow:-

------------------------------------------------------------------

 MJD(Start)| Exposure(s) | Stacked   | Filter | Mag | Magerr |

------------------------------------------------------------------

58635.636 | 600  | No | r | 20.118 | 0.14 |

58636.685  | 5*500 | YES | r | 20.48 | 0.11 |

------------------------------------------------------------------

Magnitudes are calibrated with panstarrs in the same field. Photometric
results are found to be in agreement with (Lipunov et al., GCN 24680; Kann
et al., GCN 24684; Heintz et al., GCN 24686; Izzo et al., GCN 24687; Xin et
al., GCN 24688; Watson et al., GCN 24690; Lipunov et al., GCN 24693; Xin et
al., GCN 24697; Belkin et al., GCN 24698; Kann et al., GCN 24700;Vinko et
al., GCN 24709; Siegel, GCN 24703; Moskvitin and Uklein, GCN 24708; Belkin
et al., GCN 24712; Brajesh et al., GCN 24729). Using data of
above-mentioned GCNs along with GIT data, we found that source is fading
with a power law index of 1.52.


The fitted curve can be found here:

https://lh5.googleusercontent.com/uyI9IhOx5bbe7_Ii-eHWsaj7r2Qw1g10_Lb_HIWKd5YBp8xsYC1OCPhdvYGifF80tkEgfWI-SMZl5RqgyRisuJS4mt3tHAIBEwoyVRJwX3B2LtsjVx1V=w572

The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree
field of view, set up by the Indian Institute of Astrophysics and the
Indian Institute of Technology Bombay with support from the Indo-US Science
and Technology Forum (IUSSTF) and the Science and Engineering Research
Board (SERB) of the Department of Science and Technology (DST), Government
of India (https://sites.google.com/view/growthindia/). It is located at the
Indian Astronomical Observatory (Hanle), operated by the Indian Institute
of Astrophysics (IIA).


GRB_name: GRB190604B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  24746
SUBJECT: GRB 190604B: Enhanced Swift-XRT position
DATE:    19/06/04 18:43:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.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 206 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 190604B, 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 = 297.54058, -32.97803 which is equivalent
to:

RA (J2000): 19h 50m 9.74s
Dec (J2000): -32d 58' 40.9"

with an uncertainty of 1.9 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.


