GRB 251208C
GCN Circular 43055
Subject
GRB 251208C: GECAM-B observation of a short burst
Date
2025-12-09T16:16:20Z (3 days ago)
From
Yue Wang <m18509381757@163.com>
Via
Web form
Yue Wang, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered on-ground by GRB 251208C, at 2025-12-08T12:52:32.600 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43030) and SVOM/GRM (Yue Wang et al., GCN #43041).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of a single pulse with a duration (T90) of 0.3 +0.2/-0.2 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb251208C.png
Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS).
GCN Circular 43052
Subject
Fermi GRB 251208C: Global MASTER-Net observations report
Date
2025-12-09T15:30:32Z (3 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 251208C ( Fermi GBM team, GCN 43030) errorbox 1 days 6304 sec after notice time and 1 days 6326 sec after trigger time at 2025-12-09 14:37:58 UT, with upper limit up to 15.6 mag. Observations started at twilight. The observations began at zenith distance = 77 deg. The sun altitude is -11.0 deg.
The galactic latitude b = -39 deg., longitude l = 14 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3064550
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
92816 | 2025-12-09 14:37:58 | MASTER-Kislovodsk | (20h 51m 14.16s , -30d 11m 05.4s) | C | 180 | 12.8 |
93444 | 2025-12-09 14:49:26 | MASTER-Kislovodsk | (20h 51m 12.38s , -29d 02m 48.7s) | C | 60 | 13.6 |
93444 | 2025-12-09 14:49:26 | MASTER-Kislovodsk | (20h 46m 31.77s , -28d 42m 11.8s) | C | 60 | 14.3 |
93525 | 2025-12-09 14:50:47 | MASTER-Kislovodsk | (21h 01m 36.94s , -30d 57m 36.2s) | C | 60 | 12.5 |
93525 | 2025-12-09 14:50:47 | MASTER-Kislovodsk | (20h 56m 51.84s , -30d 36m 58.9s) | C | 60 | 13.2 |
93604 | 2025-12-09 14:52:07 | MASTER-Kislovodsk | (20h 56m 03.09s , -27d 10m 45.4s) | C | 60 | 14.7 |
93604 | 2025-12-09 14:52:07 | MASTER-Kislovodsk | (20h 51m 26.46s , -26d 50m 06.8s) | C | 60 | 15.1 |
93684 | 2025-12-09 14:53:27 | MASTER-Kislovodsk | (21h 00m 18.16s , -28d 43m 43.1s) | C | 60 | 14.0 |
93684 | 2025-12-09 14:53:27 | MASTER-Kislovodsk | (21h 04m 59.03s , -29d 04m 22.4s) | C | 60 | 13.9 |
93765 | 2025-12-09 14:54:47 | MASTER-Kislovodsk | (20h 38m 01.33s , -26d 48m 57.8s) | C | 60 | 14.5 |
93765 | 2025-12-09 14:54:47 | MASTER-Kislovodsk | (20h 42m 37.44s , -27d 09m 35.3s) | C | 60 | 14.1 |
93845 | 2025-12-09 14:56:07 | MASTER-Kislovodsk | (20h 32m 54.99s , -28d 43m 10.7s) | C | 60 | 13.1 |
93845 | 2025-12-09 14:56:07 | MASTER-Kislovodsk | (20h 37m 34.74s , -29d 03m 45.7s) | C | 60 | 12.5 |
93925 | 2025-12-09 14:57:27 | MASTER-Kislovodsk | (20h 48m 49.10s , -25d 15m 12.4s) | C | 60 | 14.9 |
93925 | 2025-12-09 14:57:27 | MASTER-Kislovodsk | (20h 44m 16.39s , -24d 54m 32.9s) | C | 60 | 15.3 |
94005 | 2025-12-09 14:58:47 | MASTER-Kislovodsk | (21h 02m 06.24s , -25d 16m 49.4s) | C | 60 | 15.1 |
94005 | 2025-12-09 14:58:47 | MASTER-Kislovodsk | (20h 57m 32.94s , -24d 56m 08.5s) | C | 60 | 15.6 |
94085 | 2025-12-09 15:00:07 | MASTER-Kislovodsk | (21h 09m 35.36s , -27d 08m 43.7s) | C | 60 | 14.6 |
94085 | 2025-12-09 15:00:07 | MASTER-Kislovodsk | (21h 04m 58.34s , -26d 48m 02.7s) | C | 60 | 14.9 |
94697 | 2025-12-09 15:10:19 | MASTER-Kislovodsk | (21h 10m 53.04s , -30d 37m 42.3s) | C | 60 | 12.2 |
94857 | 2025-12-09 15:12:59 | MASTER-Kislovodsk | (20h 35m 32.24s , -25d 17m 04.5s) | C | 60 | 13.9 |
94947 | 2025-12-09 15:14:29 | MASTER-Kislovodsk | (21h 18m 27.36s , -29d 04m 37.5s) | C | 60 | 13.4 |
94947 | 2025-12-09 15:14:29 | MASTER-Kislovodsk | (21h 13m 59.27s , -28d 44m 11.1s) | C | 60 | 13.7 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.
[1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp.
http : // www.pereplet.ru/lipunov/625.html
GCN Circular 43041
Subject
GRB 251208C: SVOM/GRM observation of a short burst
Date
2025-12-09T01:00:49Z (4 days ago)
From
Chenwei Wang at IHEP <cwwang@ihep.ac.cn>
Via
Web form
SVOM/GRM team: Chen-Wei Wang, Yue Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Frédéric Daigne (IAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by GRB 251208C (SVOM trigger reference: sb25120805) at 2025-12-08T12:52:32.600 (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43030).
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 0.36 +0.06/-0.08 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb251208C.png
In addition, the position of this burst, as determined by Fermi/GBM (RA = 312.8 deg, Dec = -30.7 deg, Error=4.8 deg, GCN #43030), is located at about 84 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-0.12 to T0+0.04 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -0.54 +0.22/-0.19 and the cutoff energy, parameterized as Epeak, is 617 +241/-151 keV. The event fluence (10-1000 keV) in this time interval is (1.18 +0.09/-0.12)E-06 erg/cm^2.
The localization of GRB 251208C in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251208C_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: Chen-Wei Wang (IHEP) (cwwang@ihep.ac.cn)
GCN Circular 43030
Subject
GRB 251208C: Fermi GBM Final Real-time Localization
Date
2025-12-08T13:03:09Z (4 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 SHORT GRB
At 12:52:32 UT on 8 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251208C (trigger 786891157.548312 / 251208536).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 312.8, Dec = -30.7 (J2000 degrees, equivalent to J2000 20h 51m, -30d 41'), with a statistical uncertainty of 4.8 degrees.
The angle from the Fermi LAT boresight is 84.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251208536/quicklook/glg_skymap_all_bn251208536.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/bn251208536/quicklook/glg_healpix_all_bn251208536.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251208536/quicklook/glg_lc_medres34_bn251208536.gif