TITLE:   GCN CIRCULAR
NUMBER:  6794
SUBJECT: GRB 070917: MITSuME Akeno Ic upper limit
DATE:    07/09/17 19:10:51 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

T. Ishimura, T. Shimokawabe, N. Vasquez, Y. Yatsu, Y. Kudou and
N. Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:
 
We observed the field of GRB070917 (Cummings et al. GCN 6791)
with the 3-color 50cm MITSuME Telescope at Akeno, Japan starting 
at 09:46:58 UT, 2.2 hours after the trigger.
Although the observation was performed in three bands (Ic, Rc, and g'),
only the data in Ic band are usable for reliable comparison to 
catalogued sources because of the poor sky condition in the dusk 
with thin clouds.

We did not detect a new source in the BAT error circle.  The 3-sigma
limiting magnitude based on USNO-B1.0 (I-band) stars is following.

Filter   start time   end time    Exposure   Mag (3-sigma UL)  
-----------------------------------------------------------
 Ic      09:46:58　   10:08:08　　13 x 60s    17.8
-----------------------------------------------------------