GCN Circular 30527
Subject
GRB 210725A: Swift/UVOT Upper Limits
Event
Date
2021-07-27T00:40:13Z (5 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and M. G. Bernardini (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210725A
114 s after the BAT trigger (Bernardini et al., GCN Circ. 30501).
No optical afterglow consistent with the XRT position (Perri et al. GCN Circ. 30517)
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) 114 264 147 >20.7
u (fc) 273 523 246 >20.2
white 114 1545 392 >21.0
v 603 1595 117 >19.1
b 529 1519 97 >20.4
u 273 1495 343 >20.4
w1 653 1470 97 >19.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.047 in the direction of the burst
(Schlegel et al. 1998).