GCN 43561: GRB 260128B: SVOM detection of a burst through offline search

M. Brunet (IRAP), S. Le Stum, A. Coleiro (APC), O. Godet (IRAP),report on behalf of the SVOM team:

The SVOM/ECLAIRs telescope detected a transient source, labelled GRB 260128B, starting at 2026-01-28T06:48:34.72 UTC (T0), through an offline search with the event-by-event data downloaded through the X-band ground station.

The burst was detected within several energy ranges and timescales. The best detection is obtained by the Image Trigger with a signal-to-noise ratio of 7.5 within 4-20 keV over a time window of 10.24 seconds starting at T0-10.24s.

The lightcurve shows a single peaked structure lasting around 4s.

The localization of the source is RA, Dec = 27.734, -25.867 degrees:

RA (J2000) = 01h50m56.16s    
Dec (J2000) = -25d52m01.20s 

with a 90% C.L. radius of 12.0 arcmin (including systematic error of 6 arcmin added in quadrature).

We note that no bright catalogued X-ray sources are found in the error box.

The Space 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. ECLAIRs was developed jointly by APC, CEA, CNES, and IRAP.

The SVOM point of contact for this event  is : Sébastien Le Stum : lestum at apc.in2p3.fr

Please contact him by email if you require additional information regarding the SVOM follow-up of this burst.