TITLE:   GCN CIRCULAR
NUMBER:  8856
SUBJECT: GRB 090102: HST observations and host galaxy
DATE:    09/01/27 22:33:21 GMT
FROM:    Nial Tanvir at IofA U.Cambridge  <nrt@ast.cam.ac.uk>

A.J. Levan (Warwick), D. Malesani (DARK/NBI), N.R. Tanvir (Leicester),
A. Fruchter (STScI), J.P.U. Fynbo (DARK/NBI), J. Hjorth (DARK/NBI),
A. de Ugarte Postigo (ESO), P. Curran (MSSL), J. Graham (STScI),
K. Wiersema (U. Leicester) report:

We observed the afterglow of GRB 090102 (Mangano et al. GCN 8762;
Klotz et al. GCN 8761) using the Hubble Space Telescope and Wide Field
Planetary Camera on the 26th Jan 2009. Observations were obtained over
3 orbits (6400s), using the F606W filter. At the location of GRB 090102
we find an obvious host galaxy underlying the GRB afterglow. The magnitude
of the combined afterglow+ host at this time is R~24.5 (AB).

Astrometry utilizing early images obtained at the NOT (de Ugarte Postigo
et al GCN 8766) shows that the location of GRB 090102 is consistent with
the centroid of the galaxy/afterglow combined light (offset = 0.09 +/-
0.06").  This suggests that the afterglow may still be contributing
significantly at the current epoch. Estimates of the magnitude of any
likely point source coincident with this are inevitably uncertain, but do
allow for a continued decay with temporal index alpha~1. Later time
observations are planned, and will allow an accurate subtraction of the
host galaxy light.

Images can be found at

http://www.star.le.ac.uk/~anl/090102