GCN Circular 32531
Subject
GRB 220907A: Swift/UVOT Upper Limits
Event
Date
2022-09-08T12:26:27Z (4 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
S. R. Oates (U. Birmingham) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220907A
95 s after the BAT trigger (Page et al., GCN Circ. 32526).
No optical afterglow consistent with the enhanced XRT position
(Page and Evans GCN Circ. 32530)
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 95 245 147 >20.2
white 95 5001 298 >20.6
v 3823 4023 197 >18.6
b 4644 4844 197 >19.7
u 4438 4638 197 >19.4
w1 4234 4433 197 >19.2
m2 4028 4228 197 >19.2
w2 3618 3818 197 >19.2
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.637 in the direction of the burst
(Schlegel et al. 1998).