TITLE:   GCN CIRCULAR
NUMBER:  7675
SUBJECT: GRB080503: Swift/UVOT Upper Limits
DATE:    08/05/04 01:23:57 GMT
FROM:    Peter Brown at PSU  <pbrown@astro.psu.edu>

P. J. Brown (PSU) and J. Mao(INAF-OAB),
on behalf of the Swift/UVOT team.

The Swift Ultra-Violet/Optical Telescope (UVOT)
began settled observations of GRB 080503 (trigger 310785)
84 seconds after the BAT trigger (Mao et al.,GCN Circ. 7639).
No afterglow is detected at the enhanced XRT position
(Goad et al., GCN Circ. 7665) in the initial white finding chart
or subsequent summed images. The limiting magnitudes
(3-sigma in 5" radius apertures) in each of the UVOT filters
are as follows:

Filter  T_start(s)  T_stop(s)  Exp(s)  Mag UL (3sig)

white       85       184        98     >20.0
white       85     12500      1314     >22.3
v          191      6749      1219     >20.5
b          671     11588      1203     >21.4
u          646      7365       471     >20.3
uvw1       622      7160       471     >20.4
uvm2       597      6954       471     >20.3
uvw2       701     13219      1133     >21.0

The values quoted above are in the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627).  They are not corrected
for the expected Galactic extinction corresponding to a
reddening of E(B-V)=0.06 mag in the direction of the burst
(Schlegel et al. 1998).