GCN Circular 32063
Subject
GRB 220518A: Swift/UVOT Detection
Date
2022-05-18T15:09:29Z (3 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
S. R. Oates (U.Birmingham) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220518A
129 s after the BAT trigger (Gropp et al., GCN Circ. 32060).
A source consistent with the enhanced XRT position
(Beardmore et al. GCN Circ. 32062)
is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 03:41:22.29 = 55.34289 (deg.)
Dec (J2000) = -47:35:00.3 = -47.58342 (deg.)
with an estimated uncertainty of 0.55 arc sec. (radius, 90% confidence).
Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (FC) 129 279 147 20.00 +/- 0.25
white 621 1717 334 20.49 +/- 0.23
v 671 1767 136 >19.0
b 597 1861 131 >20.1
u (FC) 341 591 246 >19.7
u 341 1841 324 >19.9
w1 1103 1296 39 >18.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.008 in the direction of the burst
(Schlegel et al. 1998).