GCN Circular 31317
Subject
GRB 211221A: Swift/UVOT Upper Limits
Event
Date
2021-12-28T00:14:08Z (4 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) 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 211221A
63 s after the BAT trigger (Page et al., GCN Circ. 31273).
No optical afterglow consistent with the XRT position (Evans et al.
GCN Circ. 31275) 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 63 213 147 >20.7
u_FC 275 525 246 >20.1
white 63 1010 317 >21.1
v 606 799 39 >18.6
b 531 724 39 >19.4
u 275 872 285 >20.0
w1 655 848 39 >18.1
m2 631 650 19 >17.8
w2 582 774 39 >19.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.143 in the direction of the burst
(Schlegel et al. 1998).