GCN Circular 4517

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
Not found
 
 
,4513
Not found
 
 
) of GRB 060115 (Tagliaferri et al. GCN 4509
Not found
 
 
) 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)
  $B!!(BMidTime        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)
  $B!!(BMidTime        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)
  $B!!(BMidTime        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."