GCN Circular 40340
Subject
GRB 250502A: Swift/UVOT Follow up
Date
2025-05-04T20:03:01Z (18 hours ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Via
email
Paul Kuin (MSSL/UCL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began observations of the field of SVOM detected GRB
250502A 72ks after the SVOM ECLAIR trigger (Wang et al., GCN Circ.
40313).
A source consistent with the position reported by Ny Avo
Rakotondraine et al. (GCN Circ. 40315) has been
detected in the initial UVOT exposures.
The detections using the UVOT photometric system (Breeveld et al.
2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start T_stop Exp(s) Mag (Vega)
Wh 78ks 95ks 880 21.5+/- 0.35
u 72ks 106ks 3664 >21.3 (3-sigma UL)