[vsnet-grb-info 4565] GRB 070419A: MITSuME Okayama Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6329
SUBJECT: GRB 070419A: MITSuME Okayama Observations
DATE:    07/04/20 06:48:04 GMT
FROM:    Michitoshi Yoshida at Okayama Astrophysical Obs  <yoshida at oao.nao.ac.jp>

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

We performed optical imaging observation (g', Rc, and Ic) of the
field of GRB 070419A (Stamatikos et al. GCN 6302) with 50cm MITSuME
telescope at Okayama Astrophysical Observatory from UT 10:53 to
UT 13:06 on Apr.19 2007.

We coadded 106 CCD frames for each band. Exposure time of each frame
is 1 minute. We made flux calibration using a USNO B1.0 star close
to the XRT position (12:10:57.57, +39:55:40.2, B=16.14, R=15.22,
I=14.37; see Williams et al. GCN 6328, Cenko et al. GCN 6306). We
detected a faint source in g' band at the position of the optical
transient reported by Chornock et al. (GCN 6304). The g' band magnitude
and three sigma limiting magnitudes for Rc and Ic bands of this source
are listed below.

---------------------------------------------------------------
band   mid-UT          exp.time       brightness
g'     Apr. 19 12:00   106 x 1 min.   20.9 +- 0.2 mag
Rc     Apr. 19 12:00   106 x 1 min.   > 21.5 mag (upper limit)
Ic     Apr. 19 12:00   106 x 1 min.   > 19.4 mag (upper limit)
---------------------------------------------------------------