GCN Circular 45308

Wenjin Xie, Donghua Zhao(NAOC), Hui Yang, Laurent Bouchet (IRAP), Ruizhi Li (YNAO), Chao Wu (NAOC) report on behalf of the SVOM mission team:
At 2026-08-07T11:00:20 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260807A (SVOM burst-id sb26080703).

The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network.

The burst was only detected by the Count-Rate Trigger (CRT), which produced a sequence of 1 alert. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 7 in the [8-120] keV energy band over a time window of 20.40 seconds starting at 2026-08-07T10:59:59.

The localization of the best alert is R.A., Dec. 16.1480, 44.7752 degrees:
R.A. (J2000) = 1h04m35.51s
Dec. (J2000) = 44d46m30.57s
 with a 90% confidence level (C.L.) radius of 11.18 arcmin (including systematic error of 2 arcmin added in quadrature).

Due to the detection significance being below the slew threshold, no immediate slew was performed on this burst. No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being.

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. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE.

The Burst Advocate (BA) on shift for this alert is Chao WU: cwu@bao.ac.cn
Please contact the BA by email if you require additional information.