TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5104 SUBJECT: GRB 060510b: Redshift DATE: 06/05/10 14:18:08 GMT FROM: Paul Price at IfA,UH P.A. Price (IfA, Hawaii) reports on behalf of a larger collaboration: We have observed the optical afterglow of GRB 060510b (GCN #5098) with the Gemini North telesecope + GMOS. Observations consisted of 2 x 1000 sec exposures with the 400 lines/mm grating, with the source at an airmass ~ 2. Based on the presence of a strong continuum break around 7250A which we identify as due to Ly alpha, we estimate a redshift of z = 4.9. PAP thanks Nestor Mirabal for helpful discussion. We also thank the Gemini North observing team for performing these observations.