GCN Circular 19187

M. H. Siegel (PSU) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160314A
151 s after the BAT trigger (D'Elia et al., GCN Circ. 19182
Not found
 
 
).
A source consistent with the XRT position
(Osborne et al. GCN Circ. 19185
Not found
 
 
)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
  RA  (J2000) =  07:31:09.73 = 112.79053 (deg.)
  Dec (J2000) = +16:59:59.1  =  16.99974 (deg.)
with an estimated uncertainty of 0.63 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

v                  457         1825          175        >19.6
b                  407         1775          175        >19.6
u                  151          401          246         19.14 +/- 0.16
w1                 506         1726          156        >18.8
m2                 481         1849          174        >19.2
w2                 432         1801          175        >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).