TITLE: GCN GRB OBSERVATION REPORT NUMBER: 764 SUBJECT: GRB 991208 Host Galaxy Imaging DATE: 00/08/01 23:17:28 GMT FROM: Josh Bloom at CIT GRB 991208 Host Galaxy Imaging A. Diercks, J. S. Bloom, T. J. Galama, and S. R. Kulkarni report on behalf of the larger Caltech-NRAO-CARA collaboration: "We observed the field of GRB 991208 (Hurley et al. 1999, GCN #450) with the with the Echellette Spectrograph and Imager (ESI) on the Keck II 10-m Telescope on Mauna Kea at 4 April 2000 UT. A 1200-s Gunn r-band image with 0.75 arsec seeing (FWHM) reveals a galaxy at the location (Frail et al. 2000, GCN #451) of the afterglow. This galaxy, the putative host of GRB 991208, is likely responsible for the nebular emission lines previously observed spectra of the transient (Dodonov et al. 1999, GCN 475; Bloom et al. 1999, GCN 464). The galaxy appears extended with an ellipticity of ~0.3 and PA= 106 +/- 6 degrees. Using differential astrometry with respect to our early K-band image when the transient was bright (Bloom et al. 1999, GCN #480), we find the GRB was 66 +/- 63 mas (1 sigma) from the center of the galaxy; i.e. the GRB location is consistent with no offset from its host." A 39" x 39" image of the field surrounding the host galaxy is posted at http://astro.caltech.edu/~ad/grb991208-host.ps This message may be cited.