GCN Circular 39376

F. Daigne, M. Gnaoui (IAP), N. Dagoneau (CEA), S. Guillot, M. Brunet (IRAP), C.W. Wang (IHEP)
on behalf of the SVOM mission team.

At 2025-02-19T15:52:48 UTC (Tb) SVOM/ECLAIRs triggered on the gamma-ray burst GRB 250219A (SVOM burst-id sb25021904).
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), from which we received 2 alerts. IMT provided the alert with the best signal-to-noise-ratio (SNR) of 14.57 in the [5-8] keV energy band over a time window of 40.96 seconds starting at Tb.

The light curve showed a first episode of about 10 s, followed by a possibly related second episode 130 s later, with a duration of about 50 s.

The localization of the best alert is R.A., Dec 173.278, 22.684 degrees:
RA (J2000) = 11h33m06.69s
Dec (J2000) = 22d41m01.24s
with a 90% C.L. radius of 5.65 arcmin (including systematic error of 2 arcmin added in quadrature).

No immediate slew was performed on this burst. A SVOM ToO has been requested.

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.

The Burst Advocate (BA) on shift for this burst is Frédéric Daigne: daigne@iap.fr.
Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst.