[vsnet-grb-info 4335] GRB 070220: MITSuME Okayama Optical Observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6123
SUBJECT: GRB 070220: MITSuME Okayama Optical Observation
DATE:    07/02/21 09:43:09 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida at oao.nao.ac.jp>

M. Yoshida, K. Yanagisawa, (OAO, NAOJ) and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We performed optical imaging observation of the field of GRB 070220
(GCN 6114, GCN 6118) with 50cm MITSuME telescope at Okayama Astrophysical
Observatory from UT 9:57 to UT 12:11 on Feb. 20 2007.

We coadded 105 Ic band frames with a 1 minute exposure time. We made
flux calibration using USNO B1.0 catalg. The three sigma limiting magnitude
of our observation was 20.2 in Ic band. We could not find optical afterglow
candidate in the error circle reported in GCN 6118. 

----------------------------------------------------
band   mid-UT          exp.time       upper limit 
Ic     Feb. 20 11:24   105 x 1 min.   20.2 mag
----------------------------------------------------