GCN Circular 11139

Subject

GRB 100823A: Swift/UVOT Upper Limits

Event

Date

2010-08-24T04:37:39Z (16 years ago)

From

Margaret Chester at PSU <chester@astro.psu.edu>

M.M. Chester (PSU) and V. Mangano (INAF-IASFPA) report on behalf of
the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 100823A
78 s after the BAT trigger (Mangano et al., GCN Circ. 11135Loading...
 
 ).  No
optical afterglow consistent with the enhanced Swift/XRT position
(Goad et al., GCN Circ. 11136Loading...
 
 ) 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
white and u finding chart (FC) and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            78          227          147         >20.1
u_FC               290          539          246         >19.4
white               78        17439         2181         >21.9
v                  619        22361         1331         >20.5
b                  545        16528         1278         >21.3
u                  290         6512          639         >20.4
w1                 669         6307          432         >20.2
m2                 816         6102          413         >20.8
w2                 767        18242         2082         >21.2

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).