TITLE: GCN CIRCULAR NUMBER: 10747 SUBJECT: GRB 100513A: PAIRITEL NIR afterglow candidate DATE: 10/05/13 03:48:19 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan, D. A. Perley, C. R. Klein, and J. S. Bloom (UC Berkeley) report: We observed the location of GRB 100513A (Baumgartner et al., GCN 10746) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2010-05-13 03:03:07 UT, ~0.77 hours after the Swift Trigger, after sunset. In mosaics (effective exposure time of 0.92 hours) taken simultaneously in the J, H, and Ks filters, we detect a NIR source within the XRT error circle at a location: 11:18:26.8, +03:37:40 (J2000) The preliminary photometry yields: post burst t_mid (hr) exp.(s) filt mag m_err 0.93 772 J 17.7 0.1 All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values. [GCN OPS NOTE(13may10): Per author's request, the Palmer reference was change to the Baumgartner reference.]