GCN Circular 32320

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).