TITLE: GCN CIRCULAR NUMBER: 8372 SUBJECT: GRB 081008: Galaxy associated with z=1.967 absorber DATE: 08/10/14 00:17:32 GMT FROM: Antonino Cucchiara at PSU A. Cucchiara, D. B. Fox (Penn State), S. B. Cenko (Berkeley) and E. Berger (Harvard) report on behalf of a larger collaboration: "Analysis of the Gemini-South GMOS r-band acquisition image taken on October 8 (Cucchiara et al., 8346) shows the presence of an extended source at 2-arcsec distance from the afterglow of GRB 081008. The source is serendipitously located in the GMOS slit during our spectroscopic observations. Extracting the spectrum of this object reveals the presence of metal absorption features including FeII(1608), AlII(1670), NiII(1703), AlIII(1854), and CrII(2056,2062,2066) at a common redshift z=1.967. We conclude that this galaxy is associated with the strong z=1.967 absorber observed in the GRB afterglow spectrum, and is a candidate host galaxy to the GRB. The galaxy is located at (J2000) RA 18:39:49.64, Dec -57:25:53.41. At z=1.967 its 2.1-arcsec offset from the line of sight to GRB 081008 corresponds to 16 kpc in projection. We report the R-band magnitude of the GRB and the Host, calibrated using USNO catalog magnitudes of 4 nearby USNO stars: At the time of the acquisition image, 00:01 UT, we find R=18.32 +- 0.1 mag for the GRB afterglow, and R=20.75 +- 0.1 mag for the galaxy. The observed host galaxy magnitude corresponds to an absolute AB magnitude (at central wavelength 220 nm in the host galaxy frame) of M_220(AB) = -21.5 mag; assuming a comparable rest-frame B-band luminosity would place this galaxy among the brightest GRB host galaxies if it is the host galaxy of GRB 081008 (Berger et al., Apj 2007, 657). While we cannot confirm a host identification at this time, we note that the presence of an associated DLA in the VLT/FORS2 spectrum (d'Avanzo et al., GCN 8350), along with the reported absence of any absorption signature due to neutral hydrogen at z>1.967, both support this suggestion." -- Antonino Cucchiara PhD candidate Department of Astronomy&Astrophysics Penn State University website: www.astro.psu.edu/~cucchiara/