GCN Circular 31801
Subject
GRB 220325A: Swift/UVOT Upper Limits
Date
2022-03-28T16:02:38Z (3 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and M. Ferro (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220325A
114 s after the BAT trigger (Ferro et al., GCN Circ. 31787).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 31790)
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 114 264 147 >20.8
u_FC 326 576 246 >20.1
white 114 5035 488 >21.0
v 657 1234 78 >18.7
b 582 4893 255 >20.1
u 326 4688 481 >20.3
w1 707 726 19 >17.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.915 in the direction of the burst
(Schlegel et al. 1998).