GCN Circular 43882

Y. Julakanti, R. Eyles-Ferris (Univ. Leicester), S. Schanne (CEA/IRFU), H. Yang (IRAP), M.-G. Bernardini (INAF-OAB, LUPM) report on behalf of the SVOM mission team:

At 2026-02-28T20:55:55 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260228A (SVOM burst-id sb26022802).

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 7 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 10.64 in the 5-20 keV energy band over a time window of 40.96 seconds starting at 2026-02-28T20:55:34 (Tb).

The localization of the best alert is R.A., Dec. 237.8312, 26.3060 degrees:
R.A. (J2000) = 15h51m19.50s
Dec. (J2000) = 26d18m21.48s
 with a 90% confidence level (C.L.) radius of 7.51 arcmin (including systematic error of 2 arcmin added in quadrature).

The SVOM/ECLAIRs light curve showed a single broad peak structure in the Energy bands 5-8 and 8-20 keV only. The T90 duration computed in 5-120 keV is (16.6 -3.5/+7.2) s.

SVOM slewed to the burst.

No X-ray observation could be performed by SVOM/MXT for the time being because of Earth occultation.

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 Yashaswi Julakanti: skyj1@leicester.ac.uk.
Please contact the BA by email if you require additional information.