TITLE:   GCN CIRCULAR
NUMBER:  4053
SUBJECT: GRB 051001: AAT infra-red observations
DATE:    05/10/02 01:02:32 GMT
FROM:    Evert Rol at U.Leicester  <er45@star.le.ac.uk>

E. Rol (U. of Leicester), A. Levan, N. Tanvir (U. of Hertfordshire),
report on behalf of a larger collaboration:

We have observed the field of GRB 051001 (Moretti, GCN 4051) with the
IRIS2 instrument on the Anglo-Australian Telescope. Two epochs of
observations were performed in each of the ZJHKs bands, roughly 2
hours and 6 hours after the trigger, respectively. Our observations
covered the entire BAT error box, albeit with a small section (<5%) on
the edge of the FOV. Comparison between the two epochs shows no
variable sources.

Inside the XRT error circle, one source is visible, which appears to
be extended. Its location is, calibrated to the 2MASS:

  RA    23:23:49.04    (J2000)
  Dec  -31:31:18.8     (J2000)

with an estimated error of 0.16" in each coordinate.

Magnitude estimates for the first epoch, calibrated with respect to
the 2MASS, are as follows:

 filter   mid-time      exposure     magnitude        limiting
         after trigger    time      of extended        magnitude
           (hours)      (minutes)    source           (3 sigma)
   Ks       1.40           20         18.7 (0.1)        20.3
   H        1.85           20         20.0 (0.1)        20.7
   J        2.36           10         20.9 (0.3)        20.7

The first epoch Ks image can be seen at
http://www.star.le.ac.uk/~er45/grb051001/