GCN Circular 27539
Subject
GRB 200411A: Swift/UVOT Upper Limits
Event
Date
2020-04-11T09:55:39Z (6 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and A. Tohuvavohu (U. Toronto)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 200411A
58 s after the BAT trigger (Tohuvavohu et al., GCN Circ. 27536). No optical
afterglow consistent with the XRT position (Osborne et al., GCN Circ.
27538) 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 58 208 147 >20.8
u_FC 270 520 246 >20.4
white 58 1540 392 >21.2
v 601 1417 97 >18.5
b 525 1343 78 >20.3
u 270 1490 343 >21.0
w1 651 1466 97 >18.8
m2 626 646 19 >18.1
w2 576 1220 58 >19.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).