GCN Circular 32435
Subject
GRB 220730A: Swift/UVOT Upper Limits
Event
Date
2022-08-01T11:50:57Z (3 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and S. Dichiara (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220730A
112 s after the BAT trigger (Dichiara et al., GCN Circ. 32431).
No optical afterglow consistent with any of the positions in GCN Circ.
32434 (D'Ai et al.) has been 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 112 261 147 >20.5
u_FC 324 574 246 >19.8
white 112 623 167 >20.6
v 655 675 19 >17.8
b 579 599 19 >18.7
u 324 574 246 >19.8
w2 630 650 19 >18.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.161 in the direction of the burst
(Schlegel et al. 1998).