GCN Circular 23277
Subject
GRB 180924A: Swift/UVOT Upper Limits
Date
2018-09-28T04:16:50Z (6 years ago)
From
Mike Siegel at PSU/Swift MOC <siegel@swift.psu.edu>
M. H. Siegel (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 180924A
83 s after the BAT trigger (Ukwatta et al., GCN Circ. 23261).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 23262)
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 83 233 147 >20.8
u_FC 241 491 246 >19.7
white 83 542 167 >20.9
v 572 592 19 >17.1
b 497 517 19 >18.4
u 241 491 246 >19.7
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).