TITLE: GCN CIRCULAR NUMBER: 27824 SUBJECT: GRB 200524A: optical upper limits from further MITSuME Akeno observation DATE: 20/05/26 07:22:56 GMT FROM: Ryohei Hosokawa at Tokyo Institute of Technology R. Hosokawa, N. Nakamura, K. L. Murata, R. Adachi, M. Niwano, F. Ogawa, Y. Yatsu, and N. Kawai (TokyoTech) report on behalf of the MITSuME collaboration: We performed further observation of the field of GRB 200524A (Fermi-LAT detection: Dirirsa et al., GCN #27797, Fermi-GBM detection: Pookalil et al., GCN #27809, Swift-XRT afterglow detection: Capalbi et al. GCN #27811, and others) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope of Akeno Observatory, Yamanashi, Japan. The observation started on 2020-05-25 11:27:25.65 UT. We did not detect the optical afterglow (Ho et al., GCN #27799, Kumar et al., GCN #27800, Rumyantsev et al., GCN #27802, Sanwal et al., GCN #27803, Perley et al., GCN #27805, Kumar et al., GCN #27806, de Ugarte Postigo et al., GCN #27807, Blazek et al., GCN #27810, Ogawa et al., GCN #27813, Zheng et al., GCN #27814, Izzo et al., GCN #27817, Belkin et al., GCN #27820, Belkin et al., GCN #27821) in the stacked images. We obtained the 5-sigma limits as follows. T0+[hour] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 30.5 2020-05-25 11:34:26 660 g'>18.7, Rc>18.7, Ic>18.0 ------------------------------------------------------------------------------------------------ T0+: Elapsed time after the burst T-EXP: Total Exposure time We used the GSC2.3 catalog for flux calibration. The magnitudes are expressed in the Vega system. The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. ,in prep; https://github.com/MNiwano/Eclair)