GCN Circular 12389
Subject
GRB 110921A: Swift/UVOT Observations
Event
Date
2011-09-23T14:23:26Z (15 years ago)
From
Alice Breeveld at MSSL-UCL <aab@mssl.ucl.ac.uk>
A. A. Breeveld (MSSL-UCL) and W. H. Baumgartner (GSFC/UMBC) report on
behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 110921A
126 s after the BAT trigger (Baumgartner et al., GCN Circ. 12373).
A source consistent with the optical position (Xin et al., GCN Circ.
12377 and Xu et al., GCN Circ. 12385) is detected at 3.5 sigma in the
summed white data, but is not seen in any of the other filters, nor in
any of the white exposures individually.
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 126 276 147 >21.3
u_FC 284 534 246 >20.6
white 126 1704 411 21.4 �� 0.3
v 614 5307 308 >20.3
b 540 1679 117 >20.7
u 284 1654 343 >20.9
w1 664 1629 117 >21.1
m2 639 1604 117 >19.7
w2 590 1725 132 >20.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.14 in the direction of the burst
(Schlegel et al. 1998).