GCN Circular 23190
Subject
GRB 180828A: Swift/UVOT Upper Limits
Date
2018-08-29T17:21:47Z (7 years ago)
From
Sam Emery at MSSL-UCL <samuel.emery.15@ucl.ac.uk>
S.W.K. Emery (UCL-MSSL) and A. P. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180828A
124 s after the BAT trigger (Beardmore et al., GCN Circ. 23182).
No optical afterglow consistent with the XRT position
(LaPorte et al., GCN Circ. 23185) or the position of the source
detected outside the enhanced XRT error region by RATIR
(Butler et al., GCN Circ. 23189)
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 initial exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 124 23102 1057 >21.8
v 16882 39624 1367 >20.3
b 5752 28839 1439 >21.7
u 5547 34577 1709 >21.1
uvw1 5342 33925 1082 >20.7
uvm2 5137 40314 1756 >21.0
uvw2 11215 38709 2087 >21.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 23.65 in the direction of the burst
(Schlegel et al. 1998).