GRB 260928A
GCN Circular 45773
Subject
Fermi GRB 260928A: Global MASTER-Net observations report
Date
2026-09-28T04:46:18Z (7 hours ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA)
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 (Lomonosov MSU)
D.Buckley (SAAO),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)
A.Sosnovskij (Lomonosov MSU)
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory)
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez,
A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory)
R.Rebolo (The Instituto de Astrofisica de Canarias)
O.Gress, N.Budnev(ISU)
MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 260928A ( Fermi GBM team, GCN 45772) errorbox 6239 sec after notice time and 6279 sec after trigger time at 2026-09-28 02:15:56 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 52 deg. The sun altitude is -44.3 deg.
The galactic latitude b = -4 deg., longitude l = 44 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=3513224
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
6310 | 2026-09-28 02:15:56 | MASTER-OAFA | (19h 30m 04.80s , +05d 02m 26.7s) | C | 60 | 17.0 |
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 45772
Subject
GRB 260928A: Fermi GBM Final Real-time Localization
Date
2026-09-28T00:41:50Z (11 hours 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 00:31:16 UT on 28 Sep 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260928A (trigger 812248281.78187 / 260928022).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 290.5, Dec = 8.1 (J2000 degrees, equivalent to J2000 19h 22m, 8d 05'), with a statistical uncertainty of 9.8 degrees.
The angle from the Fermi LAT boresight is 44.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260928022/quicklook/glg_skymap_all_bn260928022.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/bn260928022/quicklook/glg_healpix_all_bn260928022.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260928022/quicklook/glg_lc_medres34_bn260928022.gif