GRB 260526A
GCN Circular 44723
Subject
GRB 260526A: GECAM-B observation
Date
2026-05-28T13:17:55Z (2 days ago)
From
guohx@ihep.ac.cn
Via
Web form
Hao-Xuan Guo, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team:
GECAM-B was triggered on-ground by GRB 260526A, at 2026-05-26T23:04:00.200 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #44707).
According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 42 +/-6 s.
The GECAM-B light curve can be found here:
https://www.bursthub.cn//admin/static/gecambgrb260526A.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 44708
Subject
Fermi GRB 260526A: Global MASTER-Net observations report
Date
2026-05-27T00:32:25Z (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-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 260526A ( Fermi GBM team, GCN 44707) errorbox 872 sec after notice time and 1002 sec after trigger time at 2026-05-26 23:20:42 UT, with upper limit up to 17.1 mag. The observations began at zenith distance = 79 deg. The sun altitude is -20.1 deg.
The galactic latitude b = -14 deg., longitude l = 143 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3341266
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
1032 | 2026-05-26 23:20:42 | MASTER-Tavrida | (02h 40m 21.49s , +46d 38m 05.4s) | C | 60 | 14.9 |
1113 | 2026-05-26 23:22:03 | MASTER-Tavrida | (02h 25m 12.72s , +46d 35m 35.0s) | C | 60 | 12.0 |
3275 | 2026-05-26 23:58:05 | MASTER-Tavrida | (02h 32m 55.74s , +43d 58m 52.2s) | C | 60 | 16.5 |
4690 | 2026-05-27 00:21:40 | MASTER-Tavrida | (02h 36m 20.55s , +45d 17m 15.2s) | C | 60 | 16.8 |
4769 | 2026-05-27 00:22:59 | MASTER-Tavrida | (02h 15m 28.16s , +42d 39m 11.4s) | C | 60 | 17.1 |
4848 | 2026-05-27 00:24:17 | MASTER-Tavrida | (02h 12m 43.82s , +41d 19m 58.6s) | C | 60 | 16.9 |
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 44707
Subject
GRB 260526A: Fermi GBM Final Real-time Localization
Date
2026-05-26T23:14:33Z (3 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 23:04:00 UT on 26 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260526A (trigger 801529445.20122 / 260526961).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 40.1, Dec = 43.9 (J2000 degrees, equivalent to J2000 02h 40m, 43d 53'), with a statistical uncertainty of 3.8 degrees.
The angle from the Fermi LAT boresight is 30.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260526961/quicklook/glg_skymap_all_bn260526961.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/bn260526961/quicklook/glg_healpix_all_bn260526961.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260526961/quicklook/glg_lc_medres34_bn260526961.gif