GCN Circular 6018
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."