TITLE: GCN GRB OBSERVATION REPORT NUMBER: 901 SUBJECT: GRB 001212 possible OA in 2MASS DATE: 00/12/14 23:39:32 GMT FROM: John E. Gizis at IPAC/Caltech I have checked the candidate optical counterpart (GCN 900) for GRB 001212 at RA(2000) = 06 49 38.1 Dec(2000) = +36 22 52 (+/- 2") against the Two Micron All Sky Survey (2MASS) 2nd Incremental Release. It is matched by a source observed on 1 April 1998. Source 2MASSI J0649380+362251 has J=15.220 +- 0.058, H=14.603 +- 0.083, and Ks = 14.341 +- 0.079. These colors are typical for a mid-M dwarf. Two non-GRB explanations for the observed brightening of the source are a flare or color terms between the photographic plate and the CCD. Finding charts and the 2MASS data are available by entering these coordinates at the web site: http://irsa.ipac.caltech.edu/ This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This message may be cited. John E. Gizis, IPAC/Caltech