TITLE:   GCN CIRCULAR
NUMBER:  11016
SUBJECT: GRB 100728A: Swift/UVOT Upper Limits
DATE:    10/07/28 14:01:25 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and J. K. Cannizzo (NASA/UMBC) report on behalf  
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 100728A 86s after the BAT trigger (Cannizzo et al., GCN 11004).
We do not detect a new source at the enhanced Swift XRT position
(Evans et al. GCN 11005).

The preliminary 3-sigma upper limits for the finding chart exposures  
(FC)
and summed images are:

Filter   T_start   T_stop   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white (FC)  86      236      147        >20.54
white       578     7432     657        >21.16
u     (FC)  299     548      246        >19.82
u           702     7021     490        >20.04
v           628     11695    1218       >20.06
b           554     7226     510        >20.37
uvw1        677     13337    1228       >20.62
uvm2        1255    12600    1337       >20.69
uvw2        604     7554     447        >20.19
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected
Galactic extinction corresponding to a reddening along the line of
sight of E_(B-V) = 0.18 mag. All photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).