TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4475 SUBJECT: GRB 060108: z-band imaging from Gemini-North DATE: 06/01/10 22:18:30 GMT FROM: Josh Bloom at UC Berkeley J. S. Bloom (UC Berkeley), D. Walther, C. Trujillo (Gemini), J. X. Prochaska (UCO/Lick), R. Foley (UC Berkeley), and H.-W. Chen (Chicago) report: "Using the GMOS instrument on Gemini North, we observed the field of GRB 060108 (Sakamoto et al.; GCN 4445) in z-band for 1080 sec. By comparison with the SDSS pre-imaging (Cool et al. 4448), we place an approximate 5 sigma upper limit of any afterglow flux of z = 24.2 AB mag at the position of the X-ray transient (Page et al. 4453). There is a faint enhancement (~1 sigma) at the XRT position but we cannot verify that it is indeed a real source. Further analysis of the IR imaging is on-going." A comparison chart (North up, East left) may be found at: http://astro.berkeley.edu/~jbloom/grb060108.ps This message may be cited.