GCN Circular 27268
Subject
GRB 200228B: Swift/UVOT Upper Limits
Date
2020-02-28T22:23:32Z (4 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and S. L. Laha (GSFC/UMBC/CRESST)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200228B
137 s after the BAT trigger (Laha et al., GCN Circ. 27254). No optical
afterglow consistent with the XRT position (Evans et al., GCN Circ.
#27256 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
u_FC 137 387 246 >20.1
v 4992 10685 676 >20.1
b 4580 6012 393 >20.6
u 137 5807 442 >20.4
w1 5402 5602 197 >19.5
m2 5197 5396 197 >19.8
w2 4786 6218 393 >19.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.092 in the direction of the burst
(Schlegel et al. 1998).