TITLE: GCN CIRCULAR NUMBER: 39299 SUBJECT: GRB 250211A: SVOM trigger sb25021103 is not a GRB DATE: 25/02/12 10:50:31 GMT FROM: F. Fortin at IRAP ffortin.sci.edu@gmail.com

F. Fortin (IRAP), J. Malzac (IRAP), O. Godet (IRAP), M. Brunet (IRAP) report on behalf of the SVOM mission team:

The SVOM/ECLAIRs telescope triggered at 2025-02-11T17:50:32 UTC on an uncatalogued source (SVOM trigger sb25021103).

After reviewing the ECLAIRs data, we now conclude that sb25021103 is not a GRB but likely an outburst from the Galactic transient LMXB 4U 1604-52.

We manually requested a Swift ToO, which was unfortunately requested at an incorrect sky position. Hence, none of the Swift sources from this observation (Evans, GCN 39296) are related to this trigger. We apologize for the inconvenience, and we acknowledge the excellent support from the Swift team for performing the quick ToO.

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.

The Burst Advocates (BAs) on shift for this trigger are Francis Fortin (francis.fortin@irap.omp.eu) and Julien Malzac (julien.malzac@irap.omp.eu). Please contact the BA by email if you require additional information regarding the SVOM follow-up of this event.

View this GCN Circular online at https://gcn.nasa.gov/circulars/39299. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...