TITLE:   GCN CIRCULAR
NUMBER:  14759
SUBJECT: GRB130603B: Swift/UVOT detection
DATE:    13/06/04 11:59:05 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <m.depasquale@ucl.ac.uk>

M. De Pasquale (MSSL-UCL) and A. Melandri (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130603B
62 s after the BAT trigger (Melandri et al., GCN Circ. 14735).
A source 2'' from the centre of the XRT error circle (Evans et al. GCN Circ.
14739) and coincident with the optical afterglow detected by WHT
(Levan et al., GCN circ. 14742) and NOT (de Ugarte Postigo et al., GCN circ.
14743) is detected in UVOT exposures.

The source, in UVOT images, shows no clear fading behaviour between the
first and the latest exposures.

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       62         4981        383       20.81 ±0.17
v          605         5393        225      >19.8
b          530         6212        432       21.14 ±0.45 (2.5 sigma)
u          275         6007        659       20.87 ±0.39 (2.8 sigma)
w1         654         5802        413      >20.6
m2        3960         5597        393      >20.4
w2         580         6555        365       20.69 ±0.39 (2.8 sigma)


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).