GCN Circular 5623
Subject
GRB 060926: OPTIMA-Burst -- further observations
Date
2006-09-27T00:40:02Z (18 years ago)
From
Alexander Stefanescu at MPE <astefan@mpe.mpg.de>
A. Stefanescu, F. Schrey, S. Duscha, G. Kanbach, M. Muehlegger, N.
Primak, H. Steinle (MPE Garching) of the OPTIMA-Burst Team report the
following:
We have observed the OT of GRB 060926 under unfavorable weather
conditions until it became unobservable at ~18:40 UT. To make
comparision easier with GCN 5618 (U. Kiziloglu et al.), we have
callibrated our observations against the R2-magnitudes of 4 nearby
USNO-B1 stars (1030-0324059, 1030-0324042, 1030-0324039, 1030-0324046).
We estimate the magnitude of the OT as follows:
t-t_BAT exp-time
[min] (mid-exp) [s] R_mag
-----------------------------------------------
35.4 600 20.3 +-0.5
59.7 600 20.6 +-0.5
72.7 600 20.7 +-0.7
90.7 2x 1200 21.0 +-0.7
101.2 1200 21.1 +-0.7
We fitted these values with a powerlaw with a decay index of 0.73 +-0.1.
This is significantly shallower than the powerlaw between the MASTER
observations (GCN 5619, V. Lipunov et al.) and ours, with a decay index
of 0.90 +-0.06 - allthough this could be due to incompatibilities in
zero-point.
We thank J. Papamastorakis of the University of Crete and his team for
the possibility to use the 1.3m Telescope at Skinakas Observatory for a
prolonged period of time.