[vsnet-grb-info 13881] GRB 130907A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15195
SUBJECT: GRB 130907A: Swift/UVOT Detection
DATE:    13/09/08 17:37:39 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (UCL-MSSL) and M. J. Page (UCL-MSSL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130907A
74 s after the BAT trigger (Page et al., GCN Circ. 15183).
A source consistent with the XRT position (Page et al. GCN Circ. 15183) 
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
  RA  (J2000) =  14:23:34.04 = 215.89183 (deg.)
  Dec (J2000) = +45:36:27.1  =  45.60753 (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 early exposures are: 

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

white               74          224          147         15.45 +/- 0.02
v                  616          636           20         16.29 +/- 0.16
b                  542          562           20         16.78 +/- 0.12
u                  286          536          246         15.87 +/- 0.04
w1                 666         1113          117         18.54 +/- 0.31
m2		   641         1606          117         >19.2
w2                 592          786         38         >18.7

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).