GCN Circular 565

A. Fruchter, K. Sahu, R. Gibbons, L. Petro and H. Ferguson (STScI) on 
behalf of the larger HST GRB collaboration report:

We have observed the field of GRB 990712 with the HST STIS CCD on
August 29, 1999, 48 days after outburst.  Observations with total
exposures times of 3720s were taken in both the (50CCD) clear aperture
and (LP) long pass filters.  At the position of the previously located
OT (GCN reports starting with GCN 387
Not found
 
 
), we find a disk galaxy with two
apparent knots along its major axis.  Using the astrometry of Sahu et
al. (2000, Ap J. accepted) we are able to place the position of the OT
on our image to a one-sigma accuracy no better than 0."15, where the
source of the error is nearly equally divided between that of the plate
solution in Sahu et al.'s original image and the measurement of the
relative position of the OT to the astrometric calibrators in that
image.  The best estimate position of the OT is offset from the fainter
blue knot by only 0."07; however, a brighter red knot lying 0."24 from
the best estimate position can not be ruled out as the true location of
the OT.

The images are displayed at http://www.stsci.edu/~fruchter/GRB/990712 .

These results are being published now because comments from members of
the community have made it clear that there is great interest even in
inconclusive HST results.  However, this object is scheduled to be
reobserved in late April or early May of this year.  The resulting
images, when subtracted from those reported here, should allow an
unambiguous identification of the OT, and an accurate determination of
its magnitude and color at this first HST epoch.