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GCN Circular 26125

GRB 191031D: MITSuME Akeno optical upper limits
2019-11-01T10:51:07Z (5 years ago)
Ogawa Futa at Tokyo Institute of Technology <>
F. Ogawa, R. Adachi, K. L. Murata, M. Oeda, K.Shiraishi, K. Iida, M. 
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 
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.
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