TITLE:   GCN CIRCULAR
NUMBER:  9731
SUBJECT: GRB 090727: Swift/UVOT Upper Limits
DATE:    09/07/29 02:00:58 GMT
FROM:    Margaret Chester at PSU  <chester@astro.psu.edu>

M.M. Chester (PSU) and P. A. Evans (U Leicester) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 090727
92 s after the BAT trigger (Evans et al., GCN Circ. 9718).  We do not find 
any new source at the position of the XRT afterglow (Goad et al., GCN Circ. 
9721). Preliminary 3-sigma upper limits for the white finding chart and the 
co-added images, using the UVOT photometric system (Poole et al. 2008, 
MNRAS, 383, 627), are:

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

white_FC            92          241          147         >20.6
white               92         5987          541         >21.5
v                 4760        57429         3737         >21.1
b                 4145        46543         1752         >21.3
u                 3939        52323         4261         >21.8
w1                5171        51651         4625         >22.1
m2                4965        57845         4989         >22.3
w2                4556        56519         3825         >21.7

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.54 in the direction of the burst
(Schlegel et al. 1998).