GCN Circular 32159

M. Niwano, S. Sato, M. Tateda, N. Higuchi, T. Hattori, R. Hosokawa, K. 
L. Murata, M. Sasada, N. Ito, Y. Takamatsu, Y. Imai, Y. Yatsu, and N. 
Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 220527A (A. Ursi et al. GCN Circular 
#32129, The Fermi GBM team GCN Circular #32130, E. Bissaldi et al. GCN 
Circular #32131, P. A. Evans et al. GCN Circular #32132, J. Mangan et 
al. GCN Circular #32133, B. Sbarufatti et al. GCN Circular #32135, 
Tohuvavohu et al. GCN Circular #32136, Y. Imai et al. GCN Circular 
#32138, K. Yamaoka et al. GCN Circular #32139, R. Gopalakrishnan et al. 
GCN Circular #32140, D. Xu et al. GCN Circular #32141, S. de Wet et al. 
GCN Circular #32143, P. D'Avanzo et al. GCN Circular #32145, T. Sun et 
al. GCN Circular #32146, A. Lysenko et al. GCN Circular #32152, W. Zheng 
et al. GCN Circular #32158) 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 2022-05-28 
16:06:39 UT (1.3 days after the AGILE detection). We stacked the images 
with good conditions. The point source was presumably detected at the 
Swift/XRT position (Sbarufatti et al. GCN Circular #32135) with S/N~3 
only in the Rc-band image. Here we report the Rc-band magnitude by the 
forced-photometry at the position and 5-sigma limits.

T0+[days] | MID-UT | T-EXP[sec] | magnitudes of forced-photometry | 
5-sigma limits
------------------------------------------------------------------------------------------------
1.3 | 2022-05-28 17:39:36 | 4980 | Rc=20.5+/-0.3 | g'<18.6, Rc<19.3, Ic<18.5
------------------------------------------------------------------------------------------------
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).