GCN Circular 12783

S. R. Oates (MSSL-UCL) and A. Y. Lien (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 111229A
87 s after the BAT trigger (Lien et al., GCN Circ. 12774
Not found
 
 
).
A source consistent with the XRT position (Osborne et al., GCN Circ. 12780
Not found
 
 
) and 
the GROND optical position (Nicuesa Guelbenzu et al., GCN Circ. 12780
Not found
 
 
) is 
detected in the initial UVOT exposures.

The preliminary UVOT position is:
  RA  (J2000) =  05:05:08.86 =  76.28692 (deg.)
  Dec (J2000) = -84:42:39.1  = -84.71085 (deg.)
with an estimated uncertainty of 0.55 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 (FC)        87            237           147          18.78 +/- 0.10
white            5230          5430           200          20.48 +/- 0.27
v                      630            649              20          17.70 +/- 0.49
b                     554             574             20          18.75 +/- 0.53
u (FC)            300             549           250          19.03 +/- 0.23
u                   4820          5020           200	      20.67 +/- 0.53
w1                  679           6251          413           >20.4
m2               4410           6046          393           >20.4
w2                  779        22585        1597           >21.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.18 in the direction of the burst
(Schlegel et al. 1998).