GCN Circular 975
Subject
GRB 010222, Decay Slope Confirmed
Event
Date
2001-02-23T07:16:07Z (25 years ago)
From
Javier Gorosabel at LAEFF-INTA, Madrid <jgu@laeff.esa.es>
J. P. U. Fynbo (ESO, Garching), J. Gorosabel (DSRI, Copenhagen),
B. L. Jensen, H. Pedersen, J. Hjorth (U. of Copenhagen),
M. I. Andersen (University of Oulu),
A. A. Kaas, T. Abbott, T. H. Dall and R. Oestensen (NOT), report
"Using the ALFOSC on the 2.5m Nordic Optical Telescope, we have
obtained R-band imaging of the optical counterpart of GRB 010222
(GCN #961, GCN #963). We have derived the following preliminary
magnitudes;
Date, Feb 2001(UT) R Texp(s)
=========================================
23.008--23.012 19.56+-0.03 300
23.015--23.019 19.53+-0.03 300
23.020--23.023 19.56+-0.03 300
23.083--23.086 19.65+-0.03 300
23.087--23.091 19.68+-0.03 300
23.145--23.148 19.76+-0.03 300
23.165--23.167 19.79+-0.05 100
Our zero-point is based on the the reference star 'A' of McDowell
et al. (GCN #963). We have fitted a power-law light curve to the
magnitudes reported by Stanek et al. (GCN #970) and to the ones
displayed above. We obtain a value for the slope of 0.86+-0.01
(chi^2/dof= 12.7/8=1.6), which is consistent with the one reported
by Price et al. (GCN #973)"