[vsnet-grb-info 3774] GRB060923C: AROMA optical obsevation

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5608
SUBJECT: GRB060923C: AROMA optical obsevation
DATE:    06/09/25 12:45:25 GMT
FROM:    Atsumasa Yoshida at Aoyama Gakuin U  <grbalert-ylab at phys.aoyama.ac.jp>

T.Uehara, I.Takahashi, K.Yoshida, A.Kobayashi,
D.Oyamada, Y.E.Nakagawa, S.Sugita, K.Yamaoka,
A.Yoshida (AGU) report:

We have observed the feild of GRB060923C (Stamatikos et al. GCN 5591)
from 13:35:46 (UT) with 0.3m  AROMA robotic telescope with R-band filter
at Aoyama Gakuin University.

Although the weather condition was not good, we have taken 60 frames of
image with 20s exposure each.   The photometric calibration was made
by first 5 and every 20 frames by comparing with USNO A2.0 stars
in the same field.  No new source was found. The 3 sigma
limiting magnitude of each combined image is as below.


number       mean           time since     limiting magnitude
of frames    time (UT)      GRB (s)        in R (3 sigma)
========================================================================
5            13:36:39          217                 15.4
20           13:40:20          436                 15.8
20           13:54:06          1264                16.8
20           14:10:26          2244                17.5