GCN Circular 17942

S. J. LaPorte (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150616A
579 s after the BAT trigger (Lien et al., GCN Circ. 17936
Not found
 
 
).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 17937
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           579          729          147         >21.0
white              579         7913          616         >21.8
v                  736         2624          214         >19.6
b                  836         2878          365         >20.5
u                  810         2700          214         >20.5
w1                 786         2674          214         >20.2
m2                 760         2649          136         >19.9
w2                1016         2250          156         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).