TITLE: GCN CIRCULAR NUMBER: 28779 SUBJECT: GRB 201024A: MITSuME Akeno optical upper limits DATE: 20/10/26 09:38:09 GMT FROM: Katsuhiro L. Murata at Nagoya U M. Niwano, K. L. Murata, R. Hosokawa, R. Adachi, F. Ogawa, N. Nakamura, N. Ito, S. Ogata, H. Takamatsu, H. Hara, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration: We observed the field of GRB 201024A (F. E. Marshall et al.,GCN Circular #28761) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. We observed for two nights. The observation with a series of 60 sec exposures started at 2020-10-24 16:04:04UT for the first night and 2020-10-25 15:56:17UT for the second night. We stacked the images with good conditions each night. We did not detect the point source reported by other telescopes (Lipunov et al. GCN Circular #28760, Fernandez-Garcia et al. #28763, de Ugarte Postigo et al. #28764, Martin Jelinek et al. #28766). We obtained the 5-sigma limits of the stacked images as follows. T0+[hour] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 13.78 2020-10-24T18:27:11 11520 g'>20.2, Rc>20.4, Ic>19.7 38.48 2020-10-25T17:17:59 1980 g'>19.4, Rc>19.6, Ic>18.8 ------------------------------------------------------------------------------------------------ T0+: Elapsed time after the burst T-EXP: Total Exposure time We used the PS1 catalog for flux calibration. The magnitudes are expressed in the AB system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al., accepted for publication in PASJ, https://arxiv.org/abs/2008.11486; https://github.com/MNiwano/Eclaire).