GCN 43992: GRB 260310B: Insight-HXMT/HE detection
2026-03-13T15:05:40.543Z | rev 0
Yang-Zhao Ren, Chen-Wei Wang, Cheng-Kui Li, Shao-Lin Xiong, and Chao Zheng (IHEP) report on behalf of the Insight-HXMT team:
At 2026-03-10T21:41:23.850 (T0), Insight-HXMT/HE detected a long burst, GRB 260310B, which is also detected by Fermi/GBM (Fermi GBM team, GCN #43955), and GECAM-B (Ren et al., GCN #43967).
The Insight-HXMT/HE light curve mainly consists of multi-pulses with T90 of 43.5 +5.5/-7.5 s. The 1s peak rate, measured from T0+0.25 s, is 1147 cnts/sec. Insight-HXMT/HE detected a total of 11204 counts from this burst.
The Insight-HXMT /HE light curve can be found here:
https://www.bursthub.cn//admin/static/hxmtgrb260310B.png
All measurements above are made with the CsI detectors of Insight-HXMT/HE operating in the regular mode with the energy range of about 60-900 keV (deposited energy). Only gamma-rays with energy greater than about 200 keV can penetrate the spacecraft and leave signals in the CsI detectors installed inside of the telescope.
Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://hxmten.ihep.ac.cn/
GCN 43967: GRB 260310B: GECAM-B observation of a burst
2026-03-12T05:08:05.482Z | rev 0
Yang-Zhao Ren, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered on-ground by GRB 260310B, at 2026-03-10T21:41:26.000 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #43955).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 46 +6/-7 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260310B.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 43956: Fermi GRB 260310B: Global MASTER-Net observations report
2026-03-10T22:30:30.843Z | rev 0
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 260310B ( Fermi GBM team, GCN 43955) errorbox 542 sec after notice time and 552 sec after trigger time at 2026-03-10 21:50:36 UT, with upper limit up to 16.9 mag. The observations began at zenith distance = 59 deg. The sun altitude is -50.4 deg.
The galactic latitude b = 21 deg., longitude l = 209 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3179876
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
582 | 2026-03-10 21:50:36 | MASTER-Kislovodsk | (07h 54m 35.80s , +13d 00m 23.6s) | C | 60 | 16.6 |
687 | 2026-03-10 21:52:21 | MASTER-Kislovodsk | (07h 58m 19.92s , +14d 56m 29.1s) | C | 60 | 16.9 |
790 | 2026-03-10 21:54:03 | MASTER-Kislovodsk | (07h 46m 02.42s , +14d 53m 53.7s) | C | 60 | 16.8 |
892 | 2026-03-10 21:55:45 | MASTER-Kislovodsk | (07h 51m 26.76s , +11d 07m 39.5s) | C | 60 | 16.5 |
1118 | 2026-03-10 21:59:32 | MASTER-Kislovodsk | (08h 03m 35.41s , +11d 08m 23.4s) | C | 60 | 16.6 |
1219 | 2026-03-10 22:01:12 | MASTER-Kislovodsk | (07h 50m 14.85s , +16d 47m 46.5s) | C | 60 | 16.5 |
1322 | 2026-03-10 22:02:55 | MASTER-Kislovodsk | (08h 02m 41.51s , +16d 48m 06.7s) | C | 60 | 16.7 |
1426 | 2026-03-10 22:04:39 | MASTER-Kislovodsk | (08h 10m 41.96s , +14d 55m 27.7s) | C | 60 | 16.8 |
1527 | 2026-03-10 22:06:20 | MASTER-Kislovodsk | (07h 39m 13.82s , +11d 06m 33.0s) | C | 60 | 16.6 |
1631 | 2026-03-10 22:08:04 | MASTER-Kislovodsk | (07h 48m 50.33s , +09d 12m 03.5s) | C | 60 | 16.5 |
1742 | 2026-03-10 22:09:56 | MASTER-Kislovodsk | (08h 00m 58.87s , +09d 12m 38.7s) | C | 60 | 16.7 |
1849 | 2026-03-10 22:11:42 | MASTER-Kislovodsk | (07h 37m 42.68s , +16d 48m 11.2s) | C | 60 | 16.7 |
1955 | 2026-03-10 22:13:28 | MASTER-Kislovodsk | (07h 33m 33.75s , +14d 52m 48.8s) | C | 60 | 16.5 |
2299 | 2026-03-10 22:19:12 | MASTER-Kislovodsk | (07h 30m 05.05s , +12d 59m 15.0s) | C | 60 | 16.2 |
2407 | 2026-03-10 22:21:00 | MASTER-Kislovodsk | (08h 15m 46.83s , +11d 07m 53.6s) | C | 60 | 16.6 |
2515 | 2026-03-10 22:22:48 | MASTER-Kislovodsk | (08h 15m 18.68s , +16d 48m 43.7s) | C | 60 | 16.4 |
2623 | 2026-03-10 22:24:36 | MASTER-Kislovodsk | (08h 19m 09.07s , +12d 59m 50.9s) | C | 60 | 16.8 |
2720 | 2026-03-10 22:26:13 | MASTER-Kislovodsk | (08h 07m 48.22s , +18d 41m 27.6s) | C | 60 | 16.5 |
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 43955: GRB 260310B: Fermi GBM Final Real-time Localization
2026-03-10T21:49:02.027Z | rev 0
The Fermi GBM team reports the detection of a likely LONG GRB
At 21:41:23 UT on 10 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260310B (trigger 794871688.893658 / 260310904).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 119.6, Dec = 12.9 (J2000 degrees, equivalent to J2000 07h 58m, 12d 54'), with a statistical uncertainty of 6.7 degrees.
The angle from the Fermi LAT boresight is 68.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260310904/quicklook/glg_skymap_all_bn260310904.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/bn260310904/quicklook/glg_healpix_all_bn260310904.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260310904/quicklook/glg_lc_medres34_bn260310904.gif