TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5217 SUBJECT: GRB 060512: Keck Redshift DATE: 06/06/05 11:24:28 GMT FROM: Josh Bloom at UC Berkeley GRB 060512: Keck Redshift J. S. Bloom, R. J. Foley, D. Koceveki, D. Perley (UC Berkeley) report: "On 31 May 2006 UT, we observed a source consistent with the position of the X-ray and optical afterglow of GRB 060512 (Cummings et al. GCN 5117; Mundell et al. GCN 5119) with the Keck I (+LRIS) telescope. In a single 1200 sec spectrum we detect emission features at 5380, 7014, 7155, and 7224 Ang which we identify as [O II] 3727, H beta, and [O III] 4959, 5007 at a redshift of z = 0.4428. The [O II] feature is resolved as a doublet. This source is therefore is likely the host (cf. Cenko et al. GCN 5156). This redshift confirms the hypothesis by Piranomonte et al. (GCN 5145), that z_GRB < 2.3, would apparently refute the claim that at z_GRB ~ 2.7 - 2.9 (Starling et al. GCN 5131). Analysis of other imaging and spectra is on going. Given the relatively low redshift and the current time since the burst, observations are encouraged to search for any associated supernova which would currently be near peak brightness." This message may be cited.