GCN Circular 19839
Subject
GRB 160821B: Swift/UVOT Upper Limits
Event
Date
2016-08-22T12:46:33Z (9 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and M. H. Siegel (PSU) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 160821B 76
s after the BAT trigger (Siegel et al., GCN Circ. 19833).
No optical afterglow consistent with the XRT position (Evans et al. GCN
Circ. 19837) or the NOT position (Xu et al. GCN Circ. 19834) 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 76 226 147 >21.1
u_FC 288 501 209 >20.4
white 76 6306 344 >21.7
v 5080 5280 197 >19.1
b 5901 6101 197 >20.2
u 288 5895 406 >20.6
w1 5491 5691 197 >19.6
m2 5285 5485 197 >19.5
w2 4875 6439 322 >20.1
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.05 in the direction of the
burst (Schlegel et al. 1998).