[vsnet-grb-info 13289] GRB 130511A: Kanata/HOWPol optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14626
SUBJECT: GRB 130511A: Kanata/HOWPol optical observation
DATE:    13/05/12 04:34:23 GMT
FROM:    Koji Kawabata at HASC,Hiroshima U  <kawabtkj at hiroshima-u.ac.jp>

K. Takaki, K. Kawaguchi, K. S. Kawabata, M. Ohno and M. Yoshida 
(Hiroshima Univ.) report on behalf of Kanata team:

We performed optical observations of GRB 130511A (Krimm et al., GCN 14620)
with HOWPol attached to the 1.5-m Kanata telescope at Higashi-Hiroshima
Observatory, Japan. The observation started at 11:32 UT on 2013 May 11 
with imaging-polarimetry mode, followed by observation with imaging mode 
after 12:10 UT. We detected the optical afterglow of the GRB.

Photometric results are shown below. We calibrated the Rc magnitude using
USNO-B1.0 R2 magnitudes of nearby stars. Our result seems to be consistent 
with the brightness upper-limits reported in Xin et al. (GCN 14623) and 
Kuroda et al. (GCN 14625). The decline rate between these two epochs can 
be approximated by a single power-law with an index of -0.7.

Mid time from  Total Exp   Filter    Magnitude
trigger (s)    (s)
-------------------------------------------------
2571            300x2        Rc    20.0+-0.1
8768            300x2        Rc    21.0+-0.2
-------------------------------------------------

This message may be cited.