GCN Circular 22570
Subject
GRB 180331A: Swift/UVOT Upper Limits
Event
Date
2018-03-31T11:26:21Z (8 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and C. B. Markwardt (GSFC) report
on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB
180331A 116 s after the BAT trigger (Markwardt et al., GCN Circ.
22568). No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 22569) 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 116 266 147 >20.2
u_FC 274 524 246 >19.9
white 116 1373 371 >20.4
v 604 1250 78 >18.6
b 530 1350 78 >19.4
u 274 524 246 >19.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.60 in the direction of the burst
(Schlegel et al. 1998).