GCN Circular 17790

S. R. Oates (IAA-CSIC/UCL-MSSL) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150430A
115 s after the BAT trigger (D'Elia et al., GCN Circ. 17789
Not found
 
 
).
No optical afterglow consistent with the XRT position 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           115          265          147         >20.6
u_FC               273          523          246         >19.7
white              115         5422          344         >21.2
v                 4196         5832          393         >19.8
b                 5017         6487          231         >20.3
u                  273         6447          639         >20.3
w1                4607         6242          393         >20.4
m2                4401         6037          393         >20.7
w2                3990         5627          393         >20.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).