TITLE: GCN CIRCULAR NUMBER: 27429 SUBJECT: GRB 200324A:MITSuME Akeno optical upper limits DATE: 20/03/24 17:45:42 GMT FROM: Ryohei Hosokawa at Tokyo Institute of Technology R. Hosokawa,R. Adachi, K. L. Murata, M. Oeda, K. Shiraishi, K. Iida, M. Niwano, F. Ogawa, S. Toma, N. Nakamura, Y. Yatsu, and N. Kawai(TokyoTech) report on behalf of the MITSuME collaboration: We searched for the optical counterpart of GRB 200324A (S. Dichiara et al., GCN Circular #27428) 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 16:42:46 UT. We did not find any new point sources within the Swift XRT circle (S. Dichiara et al., GCN Circular #27428) in all three bands. We obtained the 5-sigma limits as follows. T0+[sec] MID-UT T-EXP[sec] 5-sigma limits ------------------------------------------------------------------------------------------------ 219 16:46:39 420 g'>18.9,Rc>18.6,Ic>17.6 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used UCAC4 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. ,in prep; https://github.com/MNiwano/Eclair)