GCN Circular 14857

M. H. Siegel (PSU) and H. A. Krimm (CRESST/GSFC/USRA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130609B
85 s after the BAT trigger (Krimm et al., GCN Circ. 14841
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 ).
A fading source consistent with the XRT position (Goad et al. GCN Circ.
14847
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 ) is detected in the initial UVOT exposures.

The preliminary UVOT position is:
   RA  (J2000) =  03:35:05.11 =  53.77128 (deg.)
   Dec (J2000) = -40:10:26.7  = -40.17409 (deg.)
with an estimated uncertainty of 0.50 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 first and second orbit
exposures are: 

Filter        T_start(s)   T_stop(s)    Exp(s)      Mag
white (fc)           84          234      147    15.47+-0.02
white               577         1891      283    17.36+-0.03
white              6046         7681      393    18.39+-0.05
v                   799         1941      136    16.89+-0.09
v                  6457         6657      196    18.00+-0.15
b                   552         1866      136    17.32+-0.06
b                  5841         7476      393    18.46+-0.09
u (fc)              297          546      245    16.31+-0.04
u                   700         1841      116    17.15+-0.08
u                  5636         7271      393    18.15+-0.09
uvw1                676         1816      136    17.61+-0.12
uvw1               5432         7067      393    18.75+-0.15
uvm2                823         1791      116    19.12+-0.35
uvm2               6662         6861      196    >19.66
uvw2                603         1916      116    >19.51
uvw2               6252         7855      362    >20.39

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).