TITLE:   GCN CIRCULAR
NUMBER:  40340
SUBJECT: GRB 250502A: Swift/UVOT Follow up
DATE:    25/05/04 20:03:01 GMT
FROM:    Paul Kuin at MSSL <npkuin@gmail.com>

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)