GRB 251013A
GCN Circular 42252
Subject
GRB 251013A: CALET Gamma-Ray Burst Monitor detection
Date
2025-10-14T11:06:25Z (5 days ago)
From
Yuta Kawakubo at Aoyama Gakuin University <kawakubo@phys.aoyama.ac.jp>
Via
Web form
S. Sugita, A. Yoshida, T. Sakamoto, 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 GRB 251013A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 42213;
SVOM/GRM observation: Wang et al., GCN Circ. 42218) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 08:04:04.90 UTC on 13 October 2025
(https://cgbm.calet.jp/cgbm_trigger/flight/1444377382/index.html).
The burst signal was seen by only the SGM detector.
The burst light curve shows a single pulse that starts
at T+0.55 sec, peaks at T+1.32 sec, and ends at T+1.85 sec.
The T90 and T50 durations measured by the SGM data are 1.20 +/- 0.16 sec
and 0.50 +/- 0.11 sec (40-1000 keV), respectively.
The ground-processed light curve is available at
https://cgbm.calet.jp/cgbm_trigger/ground/1444377382/
The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.
GCN Circular 42218
Subject
GRB 251013A: SVOM/GRM observation
Date
2025-10-13T15:18:58Z (5 days ago)
From
Yue Wang <m18509381757@163.com>
Via
Web form
SVOM/GRM team: Yue Wang, Chen-Wei Wang, Wen-Jun Tan, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Stéphane Schanne (CEA), Hui Yang (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered both in-flight by GRB 251013A (SVOM trigger reference: sb25101308) at 2025-10-13T08:04:05.800 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42213).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single pulse with a T90 of 3.5 +0.9/-0.6 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb251013A.png
In addition, the position of this burst, as determined by Fermi/GBM (RA=19.9, DEC=-1.6, GCN #42213), is located at about 57 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. Marginal signal seen by ECLAIRs through the shields
With this localization, the time-averaged spectrum from T0-2 to T0+4 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -0.68 +0.13/-0.13 and the cutoff energy, parameterized as Epeak, is 142 +15/-12 keV. The event fluence (10-1000 keV) in this time interval is (2.96 +0.19/-0.17)E-06 erg/cm^2.
The localization of GRB 251013A in the 'Amati' relation diagram is shown at:
https://www.bursthub.cn//admin/static/svgrb251013A_amati.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: Yue Wang (IHEP) (yuewang@ihep.ac.cn)
GCN Circular 42214
Subject
Fermi GRB 251013A: Global MASTER-Net observations report
Date
2025-10-13T08:30:31Z (6 days ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko,
G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU),
O.Gress, N.Budnev (ISU),
C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A.Sosnovskij (CrAO),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity),
D.Buckley (SAAO),
R.Rebolo (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics 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 Juan National University) started inspect of the Fermi GRB 251013A ( Fermi GBM team, GCN 42213) errorbox 544 sec after notice time and 582 sec after trigger time at 2025-10-13 08:13:47 UT, with upper limit up to 19.4 mag. The observations began at zenith distance = 61 deg. The sun altitude is -22.2 deg.
The galactic latitude b = -63 deg., longitude l = 140 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3013630
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
642 | 2025-10-13 08:13:47 | MASTER-OAFA | (01h 20m 06.37s , -01d 28m 39.3s) | C | 120 | 19.1 |
778 | 2025-10-13 08:15:53 | MASTER-OAFA | (01h 20m 06.37s , -01d 28m 38.7s) | C | 140 | 19.3 |
940 | 2025-10-13 08:18:19 | MASTER-OAFA | (01h 20m 06.39s , -01d 28m 38.6s) | C | 170 | 19.4 |
1061 | 2025-10-13 08:21:15 | MASTER-OAFA | (01h 20m 06.42s , -01d 28m 38.7s) | C | 60 | 19.0 |
1126 | 2025-10-13 08:22:21 | MASTER-OAFA | (01h 20m 06.43s , -01d 28m 38.9s) | C | 60 | 18.9 |
1191 | 2025-10-13 08:23:26 | MASTER-OAFA | (01h 20m 06.45s , -01d 28m 38.8s) | C | 60 | 18.9 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
GCN Circular 42213
Subject
GRB 251013A: Fermi GBM Final Real-time Localization
Date
2025-10-13T08:14:36Z (6 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 08:04:05 UT on 13 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251013A (trigger 782035450.15137 / 251013336).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 19.9, Dec = -1.6 (J2000 degrees, equivalent to J2000 01h 19m, -1d 36'), with a statistical uncertainty of 2.6 degrees.
The angle from the Fermi LAT boresight is 95.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251013336/quicklook/glg_skymap_all_bn251013336.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251013336/quicklook/glg_healpix_all_bn251013336.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251013336/quicklook/glg_lc_medres34_bn251013336.gif