TITLE:   GCN CIRCULAR
NUMBER:  13582
SUBJECT: GRB 120804A: Swift/UVOT Upper Limits
DATE:    12/08/04 13:40:29 GMT
FROM:    Margaret Chester at PSU  <chester@astro.psu.edu>

M. M. Chester (PSU) and A. Y. Lien (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 120804A
97 s after the BAT trigger (Lien et al., GCN Circ. 13573).
No optical afterglow consistent with the XRT position (Osborne et al.,
GCN Circ. 13577) is detected 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) exposures and subsequent exposures are:

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

white_FC            97          247          147         >21.4
u_FC               310          560          246         >20.7
white               97         5665          453         >22.0
v                  640         6077          432         >20.6
b                  566         6706          243         >20.9
u                  310         6692          659         >21.3
w1                 689         6487          413         >20.3
m2                4646         6282          393         >21.3
w2                4237         5872          393         >21.0

The magnitudes in the table are not corrected for the Galactic  
extinction
due to the reddening of E(B-V) = 0.23 in the direction of the burst
(Schlegel et al. 1998).