TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4517
SUBJECT: GRB 060115: OT photometry with MITSuME
DATE:    06/01/16 00:35:13 GMT
FROM:    Nobuyuki Kawai at Tokyo Tech  <nkawai@hp.phys.titech.ac.jp>

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

"We have performed photometry of the afterglow candidate (Yanagisawa
et al. GCN 4510,4513) of GRB 060115 (Tagliaferri et al. GCN 4509) for
the stacked images of the entire effective exposure (42 min) and for
the subdivided half intervals, which were calibrated against the
USNO-B1.0 R2 and I2 stars:

Entire exposure:
    Exposure Start 13:14 (UT)
    Exposure End   14:10 (UT)
  　MidTime        13:42 (UT, T_burst + 34 min)
    Exp = 60sec x 42
    Rc = 19.2 +/- 0.4 mag
    Ic = 18.5 +/- 0.5 mag

First half:
    Exposure Start 13:14 (UT)
    Exposure End   13:40 (UT)
  　MidTime        13:27 (UT, T_burst + 19 min)
    Exp = 60sec x 21
    Rc = 19.1 +/- 0.5
    Ic = 17.9 +/- 0.4

Second half:
    Exposure Start 13:42(UT)
    Exposure End   14:10(UT)
  　MidTime        13:56(UT, T_burst + 48 min)
    Exp = 60sec x 21
    Rc > 19.1
    Ic > 19.0

Note that the exposures in different colors are completely synchronized.
The comparison images in three bands can be viewed at the following URL:

http://bragi.oao.nao.ac.jp/support/telescope/grb50/images/GRB060115A-Fading.pdf."