GCN Circular 39719

Y. Wang (PMO, CAS), Rui-Zhi Li (YNAO, CAS), M. Brunet, H. Yang (IRAP), T.Maiolino (LUPM), H. Goto (CEA)
on behalf of the SVOM mission team.

SVOM/ECLAIRs triggered on the gamma-ray burst GRB 250314A (SVOM burst-id sb25031405) starting at 2025-03-14T12:56:42 UTC (Tb).

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), from which we received 1 alert. CRT provided the alert with the best signal-to-noise-ratio (SNR) of 9.18 in the 8-120 keV energy band 
over a time window of 10.2 seconds starting at Tb. 

The light curve shows a single main episode, lasting ~20 s in ECLAIRs (5-120 keV) and ~10 s in GRM (5-550 keV).

The localization of the best alert is R.A., Dec 201.272, -5.293 degrees:
RA (J2000) = 13h25m05.28s  
Dec (J2000) = -05d17m36.30s
with a 90% C.L. radius of 8.62 arcmin (including systematic error of 2 arcmin added in quadrature).

The SVOM/GRM light curve can be found here:
https://www.bursthub.cn//admin/static/svgrb250314A.png

SVOM slewed to the burst.
MXT and VT began observing the field after the slew. The analysis of the recorded data will be published in a future circular. 

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 Y. Wang: wangyun@pmo.ac.cn.
Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst.