TITLE:   GCN CIRCULAR
NUMBER:  14957
SUBJECT: GRB 130701A: Swift/UVOT Detection
DATE:    13/07/01 15:06:08 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (MSSL-UCL) and N. P. M. Kuin (UCL-MSSL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130701A
with the u filter 151 s after the BAT trigger (Kuin et al., GCN Circ. 
14953).
A source consistent with the enhanced XRT position (Beardmore et al., 
GCN Circ. 14955) and NOT position (Leloudas et al., GCN Circ. 14954) is 
detected in the initial UVOT exposures. There is a faint USNO-B1 source 
2.16" away (USNO-B1 1261-054544, with B2 mag of 21.10) which perhaps 
could be the host galaxy for the GRB.

Preliminary detections 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

u_FC               151          400          246         15.52 ± 0.1
v                 5950         6150          197         19.04 ± 0.2
b                 5538         5737          197         19.66 ± 0.2
w2                5744         5944          197         20.07 ± 0.4

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.09 in the direction of the 
burst (Schlegel et al. 1998).