GCN Circular 11969
Subject
GRB 110422A: Swift/UVOT Detection of optical afterglow
Event
Date
2011-04-23T13:02:09Z (15 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A. A. Breeveld (MSSL-UCL) and V. Mangano (INAF-IASFPA)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110422A
822 s after the BAT trigger (Mangano et al., GCN Circ. 11957).
An optical afterglow consistent with the optical position found by
Klunko et al. (GCN 11958) and others is found in the UVOT, and is
clearly fading. It is detected in initial exposures in both white and
b, and also in v and u when the initial exposures are summed up.
Preliminary magnitudes and 3-sigma upper limits using the UVOT
photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 822 972 147 18.80 �� 0.12
white (summed) 1054 1766 97.2 19.5 �� 0.23
white 7837 8037 197 >20.4
v (summed) 1104 2336 156 18.72 �� 0.35
b 1029 1049 19.4 18.02 �� 0.3
b (summed) 1202 2435 156 18.97 �� 0.22
u (summed) 1004 2410 175 18.8 �� 0.26
w1 (summed) 980 2385 175 >19.4
m2 (summed) 1128 2360 156 >19.4
w2 (summed) 1079 2310 156 >19.6
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).
[GCN OPS NOTE(23apr11): Per author's request, the spelling on the Klunko
reference was corrected.]