TITLE:   GCN CIRCULAR
NUMBER:  32435
SUBJECT: GRB 220730A: Swift/UVOT Upper Limits
DATE:    22/08/01 11:50:57 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and S. Dichiara (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220730A
112 s after the BAT trigger (Dichiara et al., GCN Circ. 32431).
No optical afterglow consistent with any of the positions in GCN Circ.
32434 (D'Ai et al.) has been 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           112          261          147         >20.5
u_FC               324          574          246         >19.8
white              112          623          167         >20.6
v                  655          675           19         >17.8
b                  579          599           19         >18.7
u                  324          574          246         >19.8
w2                 630          650           19         >18.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.161 in the direction of the burst
(Schlegel et al. 1998).