TITLE:   GCN CIRCULAR
NUMBER:  13397
SUBJECT: GRB 120624B: Swift/UVOT Upper Limits
DATE:    12/06/28 13:17:00 GMT
FROM:    Alice Breeveld at MSSL-UCL  <aab@mssl.ucl.ac.uk>

A. A. Breeveld (MSSL/UCL), F. E. Marshall (NASA/GSFC) and J.Racusin 
(GSFC) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 120624B
60hours 45mins after the BAT trigger (Barthelmy et al., GCN Circ. 13381).
No optical afterglow is found at either of the XRT positions 
(Littlejohns et al. GCN 13394) nor the HAWKI position reported by 
D'Avanzo et al. (GCN 13391) in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent summed exposures are:

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

white_FC        218726       218864          136         >20.9
white           218865       260947         7027         >23.1

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.06 in the direction of the 
burst (Schlegel et al. 1998).