GCN Circular 20307
Subject
GRB 161220A: Swift/UVOT Upper Limits
Date
2016-12-20T17:10:33Z (7 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F. E. Marshall (NASA/GSFC) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 161220A
78 s after the BAT trigger (D'Elia et al., GCN Circ. 20302).
No optical afterglow consistent with the XRT position
(D'Elia et al. GCN Circ. 20302)
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 78 228 147 >20.5
white 78 1012 295 >21.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).