TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4628 SUBJECT: GRB 060121: Gemini Late-time Observations DATE: 06/02/01 23:40:43 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko, E. Ofek (Caltech), D. B. Fox (Penn State), and E. Berger (Carnegie) report on behalf of a larger collaboration: We have imaged the region of the short-hard GRB060121 (GCNs 4550, 4551) with the GMOS instrument on the Gemini North Telescope. Images consisted of 3 x 360 s exposures taken in r' and 5 x 210 s exposures taken in i' at a mean epoch of approximately Feb. 1.55. The 3-sigma limiting magnitude of these images, estimated with respect to the SDSS field calibration (GCN 4554), is approximately r' > 25.6, i' > 25.4. We find no evidence for any source within 0.5" of the transient reported by Malesani et al. (GCN 4561) to the limits stated above. However, within the XRT error circle (GCN 4560), approximately 1" to the east of the OT position, we find evidence for a marginal source. The coordinates of this source (J2000.0) are: RA: 09:09:52.019 Dec: +45:39:45.45 We estimate photometry for this object as r' ~ 26.4, i' ~ 26.0, although the errors on these measurements are very large due to 1) the faintness of the object, and 2) an unexpectedly large scatter in the photometric zeropoint. We note that this position likely coincides with the possible identification of a host galaxy in the NIR by Hearty et al. (GCN 4604).