[vsnet-grb-info 10059] GRB110102A: Swift/UVOT observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11514
SUBJECT: GRB110102A: Swift/UVOT observations
DATE:    11/01/03 12:41:16 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (MSSL-UCL) and M. De Pasquale (MSSL-UCL) report on behalf  
of the Swift-UVOT team

The Swift/UVOT began settled observations of the field of GRB 110102A
156 s after the BAT trigger (Oates et al., GCN Circ. 11509). The optical
afterglow is detected in the white, v, b and u filters at a refined UVO
position RA(J2000)= 245.88087 deg, DEC(J2000) = 7.61383, which is:

  RA (J2000) =   16:23:31.41
  Dec (J2000) = +07:36:49.8

with an estimated uncertainty of 0.5 arcsec (radius, 90% confidence).
This position is consistent with the enhanced XRT position (Goad et  
al., GCN Circ. 11510).
The detection in u suggests a redshift of <2.5.

Preliminary magnitudes using the UVOT photometric system (Poole et al.  
2008,
MNRAS, 383, 627) for single and summed exposures are:

Filter  T_start(s)  T_stop(s)   Exp(s)       Mag/3sigUL
#####################################################
wh (FC) 156          306        147       17.97 +/- 0.06
wh          868          1018      147       18.39 +/- 0.08
u  (FC)   314          564        246       17.98 +/- 0.09
u             1122       1315      39          18.89 +/- 0.62
v             816          835        19          17.86 +/- 0.53
b             597          589        19          17.60 +/- 0.20
uvw1      693         6331      452        > 20.09
uvm2      668         6126      292        > 19.87
uvw2      619         7152      471        > 20.35
#####################################################

The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).