TITLE:   GCN CIRCULAR
NUMBER:  8027
SUBJECT: GRB080727A: Swift/UVOT Upper Limits
DATE:    08/07/27 14:38:23 GMT
FROM:    Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>

W.B. Landsman (NASA/GSFC/Adnet) and S. Immler (PSU) report on behalf of 
the Swift/UVOT team:

The Swift/UVOT observed the field of GRB080727A starting 113s after the 
BAT trigger (Immler et al., GCN Circ. 8021).   We do not find any 
source, in any of the UVOT observations, at the UVOT-enhanced XRT 
position of the afterglow (Evans et al. GCN Circ. 8025).  The 3-sigma 
upper limits for detecting a
source at this location in the co-added images are:

Filter    T_start   T_stop    Exp(s)    Mag (3-sigma upper limit)
-----------------------------------------------------------------
    v          219     7675     1165    >20.6
    b          700     7083      471    >20.9
    u          675     6878      490    >20.6
   uvw1        650     6673      491    >20.5
   uvm2       1541     6468      236    >20.0
   uvw2        730     7486      471    >20.8
  white        113     7284      623    >21.8
-----------------------------------------------------------------

The quoted upper limits have not been corrected for the expected 
Galactic extinction along the line of sight corresponding to a
reddening of E_{B-V} = 0.07 mag.  All photometry is on the UVOT flight 
system described in Poole et al. (2008, MNRAS, 383, 627).