GCN Circular 22579
Subject
GRB 180331B: Swift/UVOT Upper Limits
Date
2018-04-01T09:38:55Z (6 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB
180331B 668 s after the BAT trigger (Lien et al., GCN Circ. 22573).
No optical afterglow consistent with the XRT position Goad er al.,
(GCN Circ. 22575) is detected in the initial UVOT exposures,
consistent with the report of Volnova et al. (GCN Circ. 22577).
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 668 818 147 >21.2
white 668 2066 412 >21.8
v 1056 2115 136 >19.2
b 1156 2041 117 >20.3
u 1130 2016 117 >20.3
w1 849 1992 78 >20.2
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).