GCN Circular 29556
Subject
GRB 210218A: Swift/UVOT observations
Event
Date
2021-02-23T14:49:18Z (5 years ago)
From
Alexander Belles at PSU/Swift <aub1461@psu.edu>
A. Belles (PSU) and B. Sbarufatti (PSU) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210218A
approximately 170 ks after the BAT trigger (B. Sbarufatti et al., GCN 29529)
due to a Moon constraint. No optical afterglow consistent with the XRT
candidate position is detected (Osborne et al., GCN 29542).
Preliminary 3-sigma upper limit using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first exposure
is:
Filter T_start(s) T_stop(s) Exp(s) Mag
wh 170031 188263 1665 >21.65
The magnitude in the table is not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.19 in the direction of the burst
(Schlegel et al. 1998).