[vsnet-grb-info 23807] GRB 191001B: MITSuME Akeno optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25906
SUBJECT: GRB 191001B: MITSuME Akeno optical upper limits
DATE:    19/10/01 18:52:08 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata at u.phys.nagoya-u.ac.jp>

K. L. Murata, R. Adachi,  M. Oeda, K.Shiraishi, K. Iida, M. Niwano,
F. Ogawa, 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 191001B (E. Troja et
al., GCN Circular #25902) 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 17:22:09 UT. We did not find any new point
sources within the BAT on-board calculated error circle in all three bands.
We obtained the following 5-sigma limits for the magnitudes.

T0+[sec]   MID-UT    T-EXP[sec]    5-sigma limits
------------------------------------------------------------------------------------------------
~169       ~17:37    1680             g'>18.8, Rc>18.8, Ic>18.6
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used GSC2.3 catalog for flux calibration.
The magnitudes are expressed in the AB system.