GCN Circular 20919
Subject
GRB 170318B: Swift/UVOT Upper Limits
Date
2017-03-19T08:56:36Z (7 years ago)
From
Alice Breeveld at MSSL-UCL <a.breeveld@ucl.ac.uk>
A. A. Breeveld (UCL-MSSL) and A. Cholden-Brown (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 170318B
84 s after the BAT trigger (Cholden-Brown et al., GCN Circ. 20908).
No optical afterglow consistent with the XRT position (Goad et al. GCN
Circ. 20910) 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 84 234 147 >20.4
u_FC 296 546 246 >19.8
white 84 6145 530 >21.0
v 626 6557 432 >19.4
b 552 5940 236 >20.0
u 296 7172 659 >20.2
w1 675 6967 432 >19.9
m2 5123 5323 197 >19.3
w2 601 6352 216 >19.6
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 4.51 in the direction of the
burst (Schlegel et al. 1998).