GRB 250211A
GCN Circular 39296
Subject
GRB 250211A: Swift ToO observations
Date
2025-02-12T01:52:54Z (4 months ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
Via
email
P. A. Evans (U. Leicester) reports on behalf of the Swift team:
Swift has initiated a ToO observation of the SVOM/ECLAIRs GRB 250211A.
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021776
Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the SVOM/ECLAIRs event. Any X-ray source
considered to be a probable afterglow candidate will be reported via a
GCN Circular after manual consideration.
Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).
This circular is an official product of the Swift-XRT team.
GCN Circular 39299
Subject
GRB 250211A: SVOM trigger sb25021103 is not a GRB
Date
2025-02-12T10:50:31Z (4 months ago)
From
F. Fortin at IRAP <ffortin.sci.edu@gmail.com>
Via
Web form
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.