GCN Circular 42100
Subject
GRB 251003A: Swift/UVOT Upper Limits
Event
Date
2025-10-03T18:33:33Z (5 days ago)
From
s.shilling@lancaster.ac.uk
Via
Web form
S. P. R. Shilling (Lancaster U.), M. De Pasquale (Univ. Messina) and
A. P. Beardmore (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 251003A
79 s after the BAT trigger (Beardmore et al., GCN Circ. 42070).
No optical afterglow consistent with the enhanced XRT position (Evans
et al., GCN Circ. 42088) or those reported by other instruments (Aceituno et al.,
GCN Circ. 42072; Moreno Méndez et al., GCN Circ. 42073; Strausbaugh et al., GCN
Circ. 42074; Worssam et al., GCN Circ. 42094), is detected in the initial UVOT
exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 79 229 147 >20.70
u 291 474 180 >19.78
v 33828 34558 711 >20.01
b 43530 43837 298 >20.30
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.408 in the direction of the burst
(Schlegel et al. 1998).