GCN Circular 26125

F. Ogawa, R. Adachi, K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. 
Niwano,
R. Hosokawa, S. Toma, Y. Yatsu, and N. Kawai (TokyoTech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 191031D (The Fermi GBM 
team, GCN Circular #26111, V. D'Elia et al., GCN Circular #26112, Bagrat 
Mailyan, #26114) 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 19/11/01 08:18:36 UT. We did not find any new 
point
sources within the XRT circle (J.P. Osborne et al., GCN Circular #26117)
in all three bands.
We obtained the following 5-sigma limits for the magnitudes.

T0+[hour]���� MID-UT������ T-EXP[sec]������ 5-sigma limits
------------------------------------------------------------------------------------------------ 

 ��~11.5���������������� 09:12:34������ 1680�������������������������� g'>18.3, Rc>18.2, Ic>17.3
------------------------------------------------------------------------------------------------ 

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.