TITLE:   GCN CIRCULAR
NUMBER:  32354
SUBJECT: GRB 220708A: Swift/UVOT Upper Limits
DATE:    22/07/09 03:01:38 GMT
FROM:    Alexander Belles at PSU/Swift  <aub1461@psu.edu>

A. Belles (PSU) and V. D'Elia (SSDC & INAF-OAR)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220708A
2473 s after the BAT trigger (D'Elia et al., GCN Circ. 32343).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 32347)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

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

white_FC          2473         2622          147         >19.8
white             2473         8325          402         >20.2
v                 2934         3134          197         >18.9
b                 2680         3954          216         >20.1
u                 2655         3749          216         >19.9
w1                2630         3544          216         >19.3
m2                3139         3339          197         >19.3
w2                2730         2930          197         >19.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.169 in the direction of the burst
(Schlegel et al. 1998).