GCN Circular 18456

B. G. Balzer (PSU) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 151022A
304 s after the BAT trigger (D'Avanzo et al., GCN Circ. 18436
Not found
 
 
).
No optical afterglow consistent with the XRT position
(Evans GCN Circ. 18438
Not found
 
 
) 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           304          454          147         >21.2
white              304         7836          902         >22.0
v                  461         8247          646         >20.1
b                  560         7632          430         >21.0
u                  535         7426          430         >21.2
w1                 510        12075          553         >19.7
m2                 486         8452          646         >20.3
w2                 609         8042          627         >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.56 in the direction of the burst
(Schlegel et al. 1998).