TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4557 SUBJECT: GRB 060121: Infrared Observations DATE: 06/01/22 06:54:35 GMT FROM: Josh Bloom at UC Berkeley J. S. Bloom, K. Alatalo (UC Berkeley) report on behalf of a larger collaboration: "We observed the field of GRB 060121 (Arimoto et al., GCN 4550; Prigozhin et al. GCN 4551) with the 1.3 meter Peters Automated Infrared Imaging Telescope (PAIRITEL) on Mt. Hopkins, Arizona, beginning at 2006-01-22 04:43:15 UT. In a stack of the first 345 seconds of integration, we find no new objects in the HETE-SXC error circle in JHKs bands brighter than the 2MASS detection levels. All significantly detected sources fainter than 2MASS have optically pre- imaged counterparts from SDSS (Cool et al. GCN 4554). Our approximate 10 sigma detection levels are J=18.7, H=17.6, Ks=16.6 mag, respectively." This message may be cited.