GCN Circular 34288
Subject
GRB 230728A: Swift/UVOT Upper Limits
Date
2023-07-28T14:37:00Z (9 months ago)
From
Samantha Oates at University of Birmingham <samantha.oates@alumni.ucl.ac.uk>
Via
email
S. R. Oates (U. Birmingham) and C. Salvaggio (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230728A
100 s after the BAT trigger (Salvaggio et al., GCN Circ. 34282).
No optical afterglow consistent with the XRT position (Evans et al.,
GCN Circ. 34286) 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 100 250 147 >20.9
u_FC 312 562 246 >20.1
white 100 1361 372 >21.1
v 641 5845 274 >19.4
b 567 1338 78 >19.5
u 312 1313 304 >20.0
w1 691 1289 58 >18.5
m2 5851 6048 194 >19.5
w2 1023 1380 52 >18.5
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.080 in the direction of the burst
(Schlegel et al. 1998).