GCN Circular 45391

Y.-H. I. Yin (HKU), Hatsune Goto (RIKEN, CEA), Clara Plasse (HKU), Donghua Zhao (NAOC), Wenjin Xie (NAOC) report on behalf of the SVOM mission team:

At 2026-08-18T01:04:36 UTC (T0), SVOM/ECLAIRs triggered and located a possible GRB (SVOM burst-id sb26081801). 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 Image Trigger (IMT), which produced a sequence of 1 alert. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 6.86 in the [8-120] keV energy band over a time window of 81.92 seconds starting at 2026-08-18T01:03:14.

The localization of the best alert is R.A., Dec. 350.0116, -32.0362 degrees:
R.A. (J2000) = 23h20m02.79s
Dec. (J2000) = -32d02m10.23s
 with a 90% confidence level (C.L.) radius of 11.41 arcmin (including systematic error of 2 arcmin added in quadrature).

We notice the presence of several quasars in this error box, among which the closest is [VV2006] J232014.7-320423 located at 3.3 arcmin.

Due to the detection significance being below the slew threshold, no immediate slew was performed on this burst. ToOs of SVOM/MXT and SVOM/VT have been scheduled for this burst.

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 Clara Plasse: clara.plasse@outlook.fr.
Please contact the BA by email if you require additional information.