GRB 250107C
GCN Circular 38870
Subject
GRB 250107C: SVOM/GRM observation
Date
2025-01-09T13:01:24Z (5 months ago)
From
Kai <wcxuemail@gmail.com>
Via
Web form
SVOM/GRM team: Wang-Chen Xue, Chen-Wei Wang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
report on behalf of the SVOM team:
During the commissioning phase, SVOM/GRM was triggered in-flight by a long burst GRB 250107C (SVOM trigger reference: sb25010702) at 2025-01-07T18:52:16.300 UTC (T0), which was also detected by GECAM-B.
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses with a duration of about 4 s.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb250107C.png
The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS.
The SVOM/GRM point of contact for this burst is: Wang-Chen Xue (IHEP)(xuewc@ihep.ac.cn)
GCN Circular 38879
Subject
IPN triangulation of GRB 250107C
Date
2025-01-09T22:04:46Z (5 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,
Y. Zhang, C. Wang, S. Xiong, J. Wei, and B. Cordier
on behalf of the SVOM-GRM team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:
The long-duration GRB 250107C
(SVOM-GRM and GECAM-B detections: Xue et al., GCN 38870)
was detected by Konus-Wind, SVOM (GRM), and GECAM-B
at about 67936 s UT (18:52:16).
We have triangulated it to a preliminary, 3 sigma error box
whose area is 22.6 sq. deg, and its maximum
dimension is 22.8 deg (the minimum one is 1.0 deg).
The Sun distance was 73 deg.
This localization may be improved.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250107_T67934/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.
The Konus-Wind time history and spectrum will be given
in a forthcoming GCN Circular.
GCN Circular 38895
Subject
Konus-Wind detection of GRB 250107C
Date
2025-01-10T15:59:26Z (5 months ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
Via
email
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The long GRB 250107C (SVOM/GRM observation: Xue et al., GCN 38870;
IPN triangulation: Svinkin et al., GCN 38879)
triggered Konus-Wind (KW) at T0=67934.719 s UT (18:52:14.719).
The burst consists of two overlapping peaks and had the total duration of ~4 s.
The emission is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB250107_T67934/
As observed by Konus-Wind, the burst had
a fluence of (3.02 ± 0.13)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 0.960 s,
of (2.23 ± 0.15)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum (measured from T0 to T0+10.752 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.41 (-0.06,+0.06),
the high energy photon index beta = -3.03 (-0.28,+0.18),
the peak energy Ep = 254 (-10,+11) keV,
chi2 = 78/79 dof.
The spectrum near the peak count rate (measured from T0+0.768 s to T0+1.024 s)
is best fit in the 20 keV - 15 MeV range
by a GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.01 (-0.13,+0.15),
the high energy photon index beta = -3.09 (-0.49,+0.29),
the peak energy Ep = 286 (-22,+21) keV,
chi2 = 30/38 dof.
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.
GCN Circular 38896
Subject
GRB 250107C: CALET Gamma-Ray Burst Monitor detection
Date
2025-01-10T16:51:07Z (5 months ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii,
Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:
The long GRB 250107C (SVOM/GRM observation: SVOM/GRM team, GCN Circ.
38870; IPN triangulation: Svinkin et al., GCN Circ. 38879; Konus-Wind detection:
Frederiks et al., GCN Circ. 38895) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 18:52:15.99 UTC on 7 January 2025
(https://cgbm.calet.jp/cgbm_trigger/flight/1420311052/index.html).
The burst signal was seen by only the SGM detector. Because of a problem with the ground
alert processing script, the GCN notice was not distributed automatically for this event.
The burst light curve shows a double-peaked structure that starts
at T-0.2 sec, peaks at T+0.7 sec, and ends at T+3.0 sec.
The T90 and T50 durations measured by the SGM data are 2.6 +/- 0.2 sec
and 1.6 +/- 0.1 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1420311052/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 39013
Subject
Improved IPN triangulation of GRB 250107C
Date
2025-01-22T15:22:14Z (4 months ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo and the HEND/Mars-Odyssey teams,
J. Benkhoff on behalf of the BepiColombo team,
D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia,
and T. Cline on behalf of the Konus-Wind team,
Y. Zhang, C. Wang, S. Xiong, J. Wei, and B. Cordier
on behalf of the SVOM-GRM team,
A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,
S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,
and
W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:
The long-duration GRB 250107C
(SVOM-GRM and GECAM-B detections: Xue et al., GCN 38870;
initial IPN triangulation: Svinkin et al., GCN 38879;
Konus-Wind detection: Frederiks et al., GCN 38895;
CALET-GBM detection: Yoshida et al., GCN 38896)
was detected by Konus-Wind, SVOM (GRM), GECAM-B, CALET (GBM),
and BepiColombo (MGNS) at about 67936 s UT (18:52:16).
We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
-------------------------------
RA(2000), deg Dec(2000), deg
-------------------------------
Corners:
348.940 +19.143
344.400 +27.679
344.615 +27.357
348.961 +19.155
-------------------------------
The error box area is 825 sq. arcmin, and its maximum
dimension is 10.5 deg (the minimum one is 1.4 arcmin).
The Sun distance was 70 deg.
This localization may be improved.
A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB250107_T67934/IPN/
The HEALPix triangulation map is the multi-order HEALPix in units of
probability density.