GCN Circular 12466
Subject
GRB 111020A: Swift/UVOT Upper Limits
Event
Date
2011-10-20T19:47:57Z (15 years ago)
From
Samantha Oates at MSSL <sro@mssl.ucl.ac.uk>
S. R. Oates (MSSL-UCL) and T. Sakamoto (NASA/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 111020A
80 s after the BAT trigger (Sakamoto et al., GCN Circ. 12460).
No optical afterglow consistent with the XRT position (Osborne et al., GCN Circ. 12463)
is detected in the initial UVOT exposures.
Preliminary 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 80 230 147 >20.0
u_FC 292 542 246 >19.6
white 80 7160 766 >20.3
v 622 6135 275 >18.8
b 547 6956 471 >19.9
u 292 18728 1973 >20.3
w1 670 18066 2242 >21.0
m2 6140 22385 2310 >21.1
w2 1027 5930 216 >20.5
This photometry may be complicated by the presence of a catalogued source
approximately 3'' away from the centre of the enhanced XRT error circle.
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.43 in the direction of the burst
(Schlegel et al. 1998).