GRB 260208C
GCN Circular 43685
Subject
GRB 260208C: AstroSat CZTI detection
Date
2026-02-10T17:14:45Z (a month ago)
From
Gaurav Waratkar at Caltech <gauravwaratkar@iitb.ac.in>
Via
Web form
M. Tembhurnikar (IUCAA), Harsha K. H. (IUCAA), S. Salunke (IUCAA), A. Arya (IITB), A. Goyal (IITB), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 260208C which was also detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 43646) and SVOM/GRM (Yue Wang, GCN Circ. 43679).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2026-02-08 15:12:17.5 UTC. The measured peak count rate associated with the burst is 99 (+40, -11) counts/s above the background in the combined data of all quadrants, with a total of 577 (+174, -169) counts. The local mean background count rate was 283 (+3, -4) counts/s. Using cumulative rates, we measure a T90 of 13 (+1, -8) s.
CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb
GCN Circular 43679
Subject
GRB 260208C: SVOM/GRM observation
Date
2026-02-10T11:05:49Z (a month ago)
From
Yue Wang <m18509381757@163.com>
Via
Web form
SVOM/GRM team: Yue Wang, Chen-Wei Wang, Xing-Hao Luo, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Marius Brunet (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered in-flight by GRB 260208C at 2026-02-08T15:12:21.000 (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43653).
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 T90 of 10 +4/-4 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb260208C.png
In addition, the position of this burst, as determined by Fermi/GBM (RA = 281.3, Dec = -49.2, Error = 2.3, GCN #43653), is located at about 107 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
With this localization, the time-averaged spectrum from T0-1 to T0+5 s is best fitted by a power law function. The power law index is -2.22 +0.13/-0.13. The event fluence (10-1000 keV) in this time interval is (4.21 +0.79/-0.72)E-06 erg/cm^2.
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 43660
Subject
Fermi GRB 260208C: Global MASTER-Net observations report
Date
2026-02-09T09:30:23Z (a month 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 [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260208C ( Fermi GBM team, GCN 43646) errorbox 63027 sec after notice time and 63048 sec after trigger time at 2026-02-09 08:43:07 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 61 deg. The sun altitude is -17.5 deg.
The galactic latitude b = -20 deg., longitude l = 347 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3126450
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
63078 | 2026-02-09 08:43:07 | MASTER-OAFA | (18h 44m 17.79s , -49d 24m 20.8s) | C | 60 | 18.5 |
63138 | 2026-02-09 08:43:07 | MASTER-OAFA | (18h 44m 17.79s , -49d 24m 20.8s) | C | 180 | 19.0 | Coadd
63154 | 2026-02-09 08:44:22 | MASTER-OAFA | (18h 44m 23.14s , -49d 24m 13.2s) | C | 60 | 18.5 |
63231 | 2026-02-09 08:45:39 | MASTER-OAFA | (18h 44m 20.60s , -49d 22m 30.2s) | C | 60 | 18.5 |
63307 | 2026-02-09 08:46:55 | MASTER-OAFA | (18h 44m 25.93s , -47d 23m 58.0s) | C | 60 | 18.5 |
63367 | 2026-02-09 08:46:55 | MASTER-OAFA | (18h 44m 25.93s , -47d 23m 58.0s) | C | 180 | 18.9 | Coadd
63385 | 2026-02-09 08:48:13 | MASTER-OAFA | (18h 44m 28.06s , -47d 22m 15.4s) | C | 60 | 18.4 |
63458 | 2026-02-09 08:49:26 | MASTER-OAFA | (18h 44m 23.21s , -47d 22m 58.9s) | C | 60 | 18.4 |
63534 | 2026-02-09 08:50:42 | MASTER-OAFA | (18h 44m 11.06s , -51d 22m 15.4s) | C | 60 | 18.6 |
63594 | 2026-02-09 08:50:42 | MASTER-OAFA | (18h 44m 11.06s , -51d 22m 15.4s) | C | 180 | 19.1 | Coadd
63610 | 2026-02-09 08:51:59 | MASTER-OAFA | (18h 44m 17.39s , -51d 23m 13.9s) | C | 60 | 18.6 |
63684 | 2026-02-09 08:53:12 | MASTER-OAFA | (18h 44m 10.04s , -51d 24m 11.4s) | C | 60 | 18.6 |
64223 | 2026-02-09 09:02:11 | MASTER-OAFA | (18h 59m 29.75s , -47d 23m 37.4s) | C | 60 | 18.2 |
64299 | 2026-02-09 09:03:27 | MASTER-OAFA | (18h 59m 22.68s , -47d 24m 34.6s) | C | 60 | 18.1 |
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 43646
Subject
GRB 260208C: Fermi GBM Final Real-time Localization
Date
2026-02-08T15:22:56Z (a month 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 15:12:18 UT on 8 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260208C (trigger 792256343.59123 / 260208634).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 281.3, Dec = -49.2 (J2000 degrees, equivalent to J2000 18h 45m, -49d 12'), with a statistical uncertainty of 2.3 degrees.
The angle from the Fermi LAT boresight is 82.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260208634/quicklook/glg_skymap_all_bn260208634.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260208634/quicklook/glg_healpix_all_bn260208634.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260208634/quicklook/glg_lc_medres34_bn260208634.gif