TITLE: GCN CIRCULAR NUMBER: 11379 SUBJECT: GRB 101023A: miniTAO/ANIR NIR detection DATE: 10/10/25 05:08:56 GMT FROM: Takeo Minezaki at U.of Tokyo/Astro K. Motohara, T. Tanabe, S. Koshida, T. Morokuma, T. Minezaki, and Y. Yoshii (University of Tokyo), report on behalf of the TAO project team: We observed GRB 101023A (Saxton et al., GCN 11363) with the near-infrared camera ANIR mounted on the miniTAO 1.0m telescope at the University of Tokyo Atacama Observatory on the summit of Co. Chajnantor (5640m altitude) in the northern Chile. The J-, H-, and Ks-band observations started from 2010-10-24 02:48 UT (3hours after the burst), and total exposure time was 540sec for each band. The afterglow was detected in all the three bands at the position reported by Levan et al. (GCN 11366). The seeing was 0.9-1.0arcsec throughout the observations, and the image of the afterglow was clearly separated from the nearby bright star. AB magnitudes are are listed below, where the flux calibrations were carried out using 2MASS stars within the FoV. Band Mid-UT AB-Mag ---------------------------- Ks 02:53:05 19.40 +/- 0.10 H 03:07:41 20.28 +/- 0.27 J 03:24:36 19.92 +/- 0.14 ----------------------------