GCN Circular 6018
Subject
GRB 050904: Second Epoch of HST/NICMOS Observations
Date
2007-01-17T19:41:48Z (18 years ago)
From
Edo Berger at Carnegie Obs <eberger@ociw.edu>
E. Berger (Carnegie Observatories) reports on behalf of a large
collaboration:
"We re-observed the position of GRB 050904 (z=6.295) with NICMOS on the
Hubble Space Telescope on 2006 July 22 UT. A total of 6 orbits (15360
sec) were obtained with the F160W (H-band) filter. Previous observations
of the burst with NICMOS on 2005 Sep 27 UT revealed a source with
F160W(AB)=26.1+/-0.2 mag (Berger et al. astro-ph/0603689), which was
interpreted as a combination of afterglow and host galaxy light. The new
observations reveal no source at the position of the burst to a 3-sigma
limit of F160W(AB)=27.2 mag. This result indicates that the host galaxy
is fainter than about 0.05 microJy, and that the light contribution from
the afterglow to the source detected in the Sep 2005 observations was
>60%, confirming the proposed jet break at t~3 days (Tagliaferri et al.
2005; Haislip et al. 2006).
A complete analysis of the new NICMOS observations, and their implications
for the afterglow and host galaxy properties, will be made available in a
revised version of astro-ph/0603689."