GRB 260520B
GCN Circular 44685
Subject
GRB 260520B: SVOM/GRM observation
Date
2026-05-21T15:23:56Z (9 days ago)
From
yzh807926@163.com
Via
Web form
SVOM/GRM team: Zheng-Hang Yu, Chen-Wei Wang, Chao Zheng, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP)
SVOM/ECLAIRs team: Olivier Godet (IRAP)
Report on behalf of the SVOM team:
SVOM/GRM was triggered on-ground by GRB 260520B at 2026-05-20T09:35:53.000 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #44676).
With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a main episode with a single peak a T90 of 6.0 +7.0/-5.0 s in the 15-5000 keV band.
The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb260520B.png
In addition, the position of this burst, as determined by Fermi/GBM (RA= 346.68 deg, DEC= 39.68 deg, ERR=14.4 deg, GCN#44425), is located at about 94 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view.
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 point of contact for this burst is: Zheng-Hang Yu (IHEP)(zhyu@ihep.ac.cn)
GCN Circular 44676
Subject
GRB 260520B: Fermi GBM Final Localization
Date
2026-05-20T18:00:48Z (10 days ago)
From
Cuán de Barra at UCD <cuan.debarra@ucdconnect.ie>
Via
Web form
The Fermi GBM team reports the detection of a likely LONG GRB
"At 09:35:52.73 UT on 20 May 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB260520B (trigger 800962557/260520400).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 346.68, Dec = 39.68 (J2000 degrees, equivalent to J2000 23h 6m, -39d 40'),
with a statistical uncertainty of 14 degrees.
The angle from the Fermi LAT boresight is 21 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260520400/quicklook/glg_skymap_all_bn260520400.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/bn260520400/quicklook/glg_healpix_all_bn260520400.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260520400/quicklook/glg_lc_medres34_bn260520400.gif"