GRB 261103A
GCN Circular 46138
Subject
GRB 261103A: LCO optical upper limits
Date
2026-11-03T15:00:08Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
Y.X. Guan(GXU), A. Saccardi (CEA/Irfu), S.J. Yin(GXU), C. Wu (NAOC), L.P. Xin, Y.Y. Shi(GXU), X.H. Han(NAOC), D. Turpin (CEA/Irfu), Y.-H.Cheng (YNU), W.-L.Zhang (PMO)
report on behalf of the SVOM mission team:
We observed the field of GRB 261103A (detected by SVOM (Brunet et al., GCN 46137) with the LCO 1m telescope at Siding Spring Observatory equipped with the Sinistro instrument.
Our observation started on 2026-11-03T12:25:42.756 UT (about 5.58 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters.
In the stacked image, we do not detect any new source within the SVOM/ECLAIRs error box. We measure the following upper limit calibrated against the Pan-STARRS DR1 catalog, and not corrected for Galactic extinction:
r > 22.11 AB (5-sigma, mid-time 5.84 hr after the trigger);
z > 19.68 AB (5-sigma, mid-time 6.31 hr after the trigger).
This project is funded by the SVOM collaboration.
GCN Circular 46137
Subject
GRB 261103A: SVOM/ECLAIRs detection of a burst through on-ground search
Date
2026-11-03T11:24:02Z (2 days ago)
From
SVOM_group <svomgroup@bao.ac.cn>
Via
Web form
M. Brunet (IRAP), Y.-H.Cheng (YNU), W.-L.Zhang (PMO) report on behalf of the SVOM/ECLAIRs team
The SVOM/ECLAIRs telescope detected a transient source, labelled GRB 261103A, starting at 2026-11-03T06:51:11 UTC (trigger time T0), through an on-ground search with the event-by-event data downloaded through the X-band ground station.
The burst was detected within several energy ranges and timescales. The best detection is obtained by the Image Trigger with a signal-to-noise ratio of 7.1 within 4-20 keV over a time window of 40.96 seconds starting at T0-40.96s.
The burst that triggered ECLAIRs onground shows a single peak lightcurve.
The localization of the source is RA, Dec = 14.157, 18.701 degrees:
RA (J2000) = 00h56m37.7s
Dec (J2000) = 18d42m03.6s
with a 90% C.L. radius of 11.04 arcmin (including systematic error of 2 arcmin added in quadrature).
We note that no bright catalogued X-ray sources are found in the error box
All the quoted errors are at the 68% confidence level.
The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC.
The Burst Advocate (BA) on shift for this alert is Y.-H.Cheng (yhcheng@mail.ynu.edu.cn)
Please contact the BA by email if you require additional information.