GCN Circular 9544

P.A. Curran (UCL-MSSL) reports on behalf of the Swift/UVOT team:


The Swift/UVOT began settled observations of the field of GRB 090621
123 s after the BAT trigger (Curran et al., GCN 9540
Not found
 
 
). No optical
afterglow consistent with the refined XRT position (Page et al., GCN 
9543
Not found
 
 
) is detected in the initial UVOT exposures. Preliminary 3-sigma 
upper limits using the UVOT photometric system (Poole et al. 2008, 
MNRAS, 383, 627) for the first exposures are:


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

wh             123         7115       805        >21.5
v              613         6089       333        >19.4
b              538         6910       310        >20.5
u              282         6705       736        >20.5
uw1            662         6500       320        >19.8
um2            637         6295       333        >19.7
uw2            588         5884       333        >19.9


The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).