TITLE: GCN CIRCULAR NUMBER: 6997 SUBJECT: GRB 060602A: host redshift DATE: 07/10/25 12:44:19 GMT FROM: Pall Jakobsson at U Hertfordshire Pall Jakobsson (U. Hertfordshire), Daniele Malesani, Johan P. U. Fynbo, Jens Hjorth, Paul M. Vreeswijk (DARK, NBI) and Nial R. Tanvir (U. Leicester) report on behalf of a larger collaboration: Using FORS1 on the Very Large Telescope, we obtained 2*20 min spectra (grism 300V+GG375 covering 4000-8000 A) of the GRB 060602A host galaxy on 28 December 2006. A firm upper limit of z < 2.3 can be placed on the host redshift from the lack of Ly-alpha forest lines in the combined spectrum. We do detect a strong emission line at 6664 A. If it corresponds to H-alpha at z = 0.015, we would expect to detect H-beta and the [O III] doublet in our spectrum. However, no features are visible at their predicted locations. In addition, this redshift would imply a very faint absolute magnitude of M_R = -10.3. If the emission line corresponds to [O III] 5008 at z = 0.331, we would expect to detect [O II] 3728 which we do not. The most probable association is with [O II] 3728, corresponding to a redshift of z = 0.787. Using the relations by Kennicutt (1998, ARA&A, 36, 189), the flux of the proposed [O II] line corresponds to a star formation rate (SFR) of approximately 1.9 M_Sun/year. This value has not been corrected for host extinction, and is therefore a strict lower limit to the actual SFR. The specific SFR is around 13.6 M_Sun/year (L/L*)^-1, typical for GRB host galaxies (Christensen et al., 2004, A&A, 425, 913).