GCN Circular 42635
Subject
GRB 251106A: Swift/UVOT Upper Limits
Event
Date
2025-11-10T15:56:36Z (18 hours ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
Via
Web form
M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 251106A 4.1 ks after the SVOM/ECLAIRs trigger (Antier et al., GCN Circ. 42605). We do not detect any afterglow consistent with the XRT position (D'Ai et al., GCN Circ. 42611) or optical position (Angulo et al., GCN Circ. 42607).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
u 4066 9896 1987 >20.56
u 199146 273340 4837 >21.08
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.016 in the direction of the burst
(Schlegel et al. 1998).