GCN Circular 29129
Subject
GRB 201221D: Swift/UVOT Upper Limits
Date
2020-12-22T13:27:07Z (4 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and K. L. Page (U. Leicester) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 201221D 92 s after the BAT trigger
(Page et al., GCN Circ. 29112). No optical afterglow consistent with the NOT or XRT position
(Malesani et al. GCN Circ. 29117; Evans et al. GCN Circ. 29119) 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_FC 92 242 147 >20.3
u_FC 305 554 246 >19.3
white 4047 4247 197 >21.0
v 634 4657 216 >19.2
u 305 5110 282 >19.4
w1 684 5068 216 >19.7
m2 4663 4863 197 >19.5
w2 4253 4453 197 >19.9
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of
E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).