GCN Circular 17424

S. R. Oates (IAA-CSIC/UCL-MSSL) and L. M. Z. Hagen (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150206A
483 s after the BAT trigger (Hagen et al., GCN Circ. 17413
Not found
 
 
).
A source consistent with the XRT position
(Goad et al. GCN Circ. 17418
Not found
 
 
)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
 RA  (J2000) =  00:40:17.63 =  10.07346 (deg.)
 Dec (J2000) = -63:10:55.7  = -63.18214 (deg.)
with an estimated uncertainty of 0.52 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

white              483          577           93         18.76 +/- 0.17
v                 2091         6690          201        >18.8
b                 2190         2912          255         19.56 +/- 0.22
u                 2165         2707           78        >19.0
w1                2140         2683           78        >18.9
w2                2414         6560          216        >19.7

The magnitudes in the table 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).