TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5397
SUBJECT: GRB 060804: Swift UVOT observations
DATE:    06/08/04 21:44:33 GMT
FROM:    Mat Page at MSSL/Swift  <mjp@mssl.ucl.ac.uk>

S. B. Pandey, M. De Pasquale, M. J. Page and 
H.Z. Ziaeepour (UCL-MSSL) report on behalf of the 
Swift/UVOT team:

The Swift UVOT began taking settled exposures
on the field of the long duration GRB 060804
(BAT Trigger #222546), 128s after the BAT trigger
(Ziaeepour et al., GCN Circ. 5394). The optical
afterglow candidate (RA(J2000) = 07h 28m 49.36s
Dec(J2000) = -27d 12' 56.7") reported by Ziaeepour 
et al. 2006 (GCN Circ. 5394) is clearly detected in 
early frames. The fading behaviour of the candidate 
before the later frames confirms that it is the 
afterglow of GRB 060804. Detections in the initial 
V and White images, and 3-sigma upper limits in the 
later, coadded images are listed below.

Filter  T_range(s)    Exposure (s)    Magnitude

White   126-225         98            17.9+-0.1
V       231-631         393           17.7+-0.1


Filter  T_range(s)    Exposure (s)    3-sigma UL

White   5211-12280      253           > 20.1
V       5621-5820       197           > 19.4
B       709-12219       944           > 20.5
U       685-18065       896           > 19.9
UVW1    661-15696       408           > 19.8
UVM2    637-6025        216           > 19.5
UVW2    5417-21845      747           > 19.7

T_range is calculated from the time of the trigger.
We caution that photometry of this afterglow
is complicated by the presence of a nearby source.

These measurements have not been corrected for the
estimated Galactic reddening of E_(B-V) = 0.657 mag
(Schlegel et al. 1998). We caution that the 
extinction estimate for this burst, which has
|Galactic latitude| < 5 deg, is unreliable.