TITLE: GCN CIRCULAR NUMBER: 32320 SUBJECT: GRB 220701A: MITSuME Akeno optical upper limits DATE: 22/07/04 06:38:32 GMT FROM: Yutaka Takamatsu at Tokyotech Y. Takamatsu, N. Ito, M. Niwano, Y. Imai, S. Sato, M. Tateda, N. Higuchi, T. Hattori, R. Hosokawa, K. L. Murata, M. Sasada, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration: We observed the field of GRB 220701A (P. A. Evans et al. GCN Circular #32306 & #32308, B. O'Connor et al. GCN Circular #32309, S. R. Oates et al. GCN Circular #32310, Y.-D. Hu et al. GCN Circular #32311, R. Strausbaugh et al. GCN Circular #32313, J. D. Gropp et al. GCN Circular #32314, WeiKang Zheng et al. GCN Circular #32315, S. Belkin et al. GCN Circular #32317, Alan M. Watson et al. GCN Circular #32318) with the optical three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno. The observation with a series of 60 sec exposures started at 2022-07-01 19:37:09 UT (884 minutes after the Swift/BAT trigger). We stacked the images with good conditions. We did not detect any uncatalogued sources within the enhanced Swift/BAT error region (Evans et al. GCN Circular #32306). We obtained the 5-sigma limits of the stacked images as follows. T0+[days] | MID-UT | T-EXP[sec] | 5-sigma limits ------------------------------------------------------------------------------------------------ 0.6 | 2022-07-01 14:31:19 | 9060 | g'>19.4, Rc>20.1, Ic>20.9 ------------------------------------------------------------------------------------------------ T0+ : Elapsed time after the burst T-EXP: Total Exposure time We used 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. 2021, PASJ, Vol.73, Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).