GCN Circular 22587
Subject
GRB 180402A: Swift/UVOT Upper Limits
Date
2018-04-03T15:38:17Z (6 years ago)
From
Sam Emery at MSSL-UCL <samuel.emery.15@ucl.ac.uk>
S.W.K. Emery (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 180402A
140 s after the BAT trigger (Lien et al., GCN Circ. 22580).
No optical afterglow consistent with the XRT position
(D'Elia et al., GCN Circ. 22586)
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 4328 4478 147 >20.8
u_FC 140 390 246 >19.7
white 4328 6805 407 >20.6
v 423 5916 286 >19.2
b 5101 6736 393 >20.2
u 140 6531 845 >20.3
w1 4691 6326 393 >20.4
w2 5512 5712 197 >19.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.77 in the direction of the burst
(Schlegel et al. 1998).