| Summary table |
|---|
| Variable |
Value |
Source |
| T0 |
10:19:44 UTC |
GCN_circulars,Swift Det |
| ra |
40.8577° |
Swift |
| decl |
-65.6862° |
Swift |
| pos_error |
2.85e-04° |
Swift |
| T90 |
5.37 s |
Swift |
| T90_start |
10:19:44 UTC |
Swift |
| fluence |
2.70e-07 erg/cm² |
Swift |
| T100 |
5.37 s |
|
| GBM_located |
False |
|
| mjd |
59967.43037037037 |
GCN_circulars,Swift Det |
| IPN table |
|---|
| GRB_name |
GRB230123A |
| ra |
40.9375° |
| decl |
-65.6833° |
| pos_error |
5.00e-02° |
| Swift table |
|---|
| GRB_name |
GRB230123A |
| t_trigger |
10:19:44 UTC |
| ra |
40.8577° |
| decl |
-65.6862° |
| pos_error |
2.85e-04° |
| T90 |
5.37 s |
| fluence |
2.70e-07 erg/cm² |
| GCN 33206 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33206 |
| Detection_method |
Swift Det |
| t_trigger |
10:19:44 UTC |
| ra |
40.9370° |
| decl |
-65.6760° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33206
SUBJECT: GRB 230123A: Swift detection of a burst
DATE: 23/01/23 10:36:16 GMT
FROM: Kim Page at U.of Leicester
M. A. Williams (PSU), R. A. J. Eyles-Ferris (U Leicester),
J.D. Gropp (PSU), J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (U Tampa) and K. L. Page (U Leicester) report on behalf of
the Neil Gehrels Swift Observatory Team:
At 10:19:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230123A (trigger=1150429). Swift slewed immediately to the burst.
The BAT on-board calculated location is
RA, Dec 40.937, -65.676 which is
RA(J2000) = 02h 43m 45s
Dec(J2000) = -65d 40' 33"
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 10 sec. The peak count rate
was ~800 counts/sec (15-350 keV), at ~1 sec after the trigger.
The immediately available BAT light curve does not include data
from ~T+8 s to ~T+100 s. There might be additional burst emission
in that time interval.
The XRT began observing the field at 10:21:13.6 UT, 88.8 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 40.85977, -65.68672
which is equivalent to:
RA(J2000) = 02h 43m 26.34s
Dec(J2000) = -65d 41' 12.2"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 120 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
https://www.swift.ac.uk/sper. We cannot determine whether the source
is fading at the present time.
A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.95 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 1.3
(+1.44/-1.26) x 10^22 cm^-2 (90% confidence).
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 12% 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
0.022.
Burst Advocate for this burst is M. A. Williams (mjw6837 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/)
|
| GCN 33208 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33208 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33208
SUBJECT: GRB 230123A: Zadko observatory - Gingin optical observations
DATE: 23/01/23 14:31:21 GMT
FROM: Bruce Gendre at UVI
B. Gendre (UWA/OzGrav), G. Stratta (INAF/Goethe University Frankfurt),
E. Moore (UWA/OzGrav), F. Panther (UWA/OzGrav), D. Coward (UWA/OzGrav),
J. A. Moore (OzGrav-UWA), A. Klotz (IRAP-CNRS-OMP), and P. Thierry (AGORA)
report:
We imaged the field of GRB 230123A detected by SWIFT
(trigger 1150429, GCN 33206, Williams et al. 2023)
with the Zadko robotic telescope (D=100cm)
located at the Zadko observatory - Gingin, Australia.
The observations started 2.56h after the GRB trigger (t0+9213.4s).
The elevation of the field decreased from
51 degrees above horizon and weather conditions
were good.
We observed the field for one hour, and have not detected any afterglow
down to magnitude 18.7 in individual images. On a stack of 6 images, we reached
an upper limit of R = 19.0 with no detection of the afterglow.
Further observations are planned.
Magnitudes were estimated with the nearby USNO-B1 stars
and are not corrected for galactic dust extinction.
N.B. Galactic coordinates are lon=286.2098 lat=-47.6419
and the galactic extinction in R band is 0.0 magnitudes
estimated from D. Schlegel et al. 1998ApJ...500..525S.
This message may be cited.
======================================================================
|
| GCN 33209 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33209 |
| Detection_method |
Swift-XRT Det |
| ra |
40.8584° |
| decl |
-65.6865° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33209
SUBJECT: GRB 230123A: Enhanced Swift-XRT position
DATE: 23/01/23 16:43:36 GMT
FROM: Phil Evans at U of Leicester
A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team.
Using 1184 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 230123A, 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 = 40.85842, -65.68648 which is equivalent
to:
RA (J2000): 02h 43m 26.02s
Dec (J2000): -65d 41' 11.3"
with an uncertainty of 4.1 arcsec (radius, 90% confidence).
This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).
This circular was automatically generated, and is an official product of the
Swift-XRT team.
|
| GCN 33210 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33210 |
| Detection_method |
Swift-XRT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33210
SUBJECT: GRB 230123A: Swift-XRT refined Analysis
DATE: 23/01/23 17:57:03 GMT
FROM: Phil Evans at U of Leicester
S. Dichiara (PSU), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto) and M.A. Williams report on behalf of the
Swift-XRT team:
We have analysed 6.4 ks of XRT data for GRB 230123A (Williams et al.
GCN Circ. 33206), from 73 s to 18.4 ks after the BAT trigger. The data
comprise 8 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Beardmore et al. (GCN Circ.
33209).
The light curve can be modelled with a power-law decay with a decay
index of alpha=0.68 (+0.08, -0.07).
A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.1 (+0.4, -0.3). The
best-fitting absorption column is 1.4 (+1.0, -0.8) x 10^21 cm^-2, in
excess of the Galactic value of 3.0 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 3.2 x 10^-11 (4.3 x 10^-11) erg
cm^-2 count^-1.
A summary of the PC-mode spectrum is thus:
Total column: 1.4 (+1.0, -0.8) x 10^21 cm^-2
Galactic foreground: 3.0 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index: 2.1 (+0.4, -0.3)
If the light curve continues to decay with a power-law decay index of
0.68, the count rate at T+24 hours will be 3.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-13 (1.4 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/01150429.
This circular is an official product of the Swift-XRT team.
|
| GCN 33211 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33211 |
| Detection_method |
Swift-UVOT Other |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33211
SUBJECT: GRB 230123A: Swift/UVOT Upper Limits
DATE: 23/01/23 19:25:47 GMT
FROM: Alexander Belles at PSU/Swift
A. Belles (PSU) and M. Williams (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230123A
93 s after the BAT trigger (Williams et al., GCN Circ. 33206).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 33209)
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 93 243 147 >20.6
u_FC 305 555 246 >20.6
white 93 1704 412 >21.0
v 637 1754 136 >19.4
b 562 1679 117 >20.0
u 305 1825 359 >20.5
w1 686 1804 117 >20.8
m2 1412 1605 39 >18.7
w2 612 1209 78 >20.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.022 in the direction of the burst
(Schlegel et al. 1998).
|
| GCN 33214 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33214 |
| Detection_method |
Swift-BAT Det |
| ra |
40.9050° |
| decl |
-65.6610° |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33214
SUBJECT: GRB 230123A: Swift-BAT refined analysis
DATE: 23/01/24 05:08:44 GMT
FROM: Amy Lien at GSFC
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU), M. A. Williams (PSU) (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 230123A (trigger #1150429)
(Williams et al., GCN Circ. 33206). The BAT ground-calculated position is
RA, Dec = 40.905, -65.661 deg which is
RA(J2000) = 02h 43m 37.3s
Dec(J2000) = -65d 39' 39.9"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 88%.
The mask-weighted light curve shows a single-peaked structure
that starts at ~T-2 s, peaks at ~T+1, and ends at ~T+6 s.
T90 (15-350 keV) is 5.37 +- 1.03 sec (estimated error including
systematics).
The time-averaged spectrum from T-1.25 to T+4.75 sec is best fit
by a simple power-law model. The power law index of the time-averaged
spectrum is 2.06 +- 0.24. The fluence in the 15-150 keV band
is 2.7 +- 0.4 x 10^-7 erg/cm2. The 1-sec peak photon flux measured from
T+0.12 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/1150429/BA/
|
| GCN 33217 table |
|---|
| GRB_name |
GRB230123A |
| GCN_number |
33217 |
| Detection_method |
Optical |
| Circular_text |
TITLE: GCN CIRCULAR
NUMBER: 33217
SUBJECT: GRB 230123A: LCOGT Optical Upper Limits
DATE: 23/01/24 17:19:20 GMT
FROM: Robert Strausbaugh at University of Minnesota
R. Strausbaugh (University of Minnesota), A. Cucchiara (NASA) report on
behalf of a larger collaboration:
We observed the GRB 230123A (Williams et al., GCN 33206) field with the
LCOGT 1-meter Sinistro instrument at the Cerro Tololo Interamerican
Observatory, Chile site, on January 24, from 02:06 to 02:38 UT
(corresponding to 15.78 to 16.32 hours from the GRB trigger time) with the
Bessel R and I filters.
We performed a series of 3x300s exposures in each band. We do not detect a
source in either band within the XRT enhanced error region (Beardmore et
al., GCN 33209), consistent with other optical upper limits (Gendre et al.,
GCN 33208; Belles et al., 33211).
The following upper limits are calculated using the USNO-B1.0 catalog as
reference:
R > 20.8
I > 20.1
These magnitudes are not corrected for galactic extinction.
|