GCN Circular 4680
Subject
GRB060203: WHT Z-band observations
Date
2006-02-05T23:28:39Z (19 years ago)
From
Evert Rol at U.Leicester <er45@star.le.ac.uk>
E. Rol (U. of Leicester), A. Levan (U. of Hertsfordshire), K. Wiersema
(U. of Amsterdam), P. Dobbie, D. Boyce (U. of Leicester), N. Tanvir
(U. of Hertsfordshire) report on behalf of a larger collabration:
We have observed the optical counterpart of GRB060203 (Malesani, GCN
4645) with the Auxiliary Port Imaging Camera on the William Herschel
Telescope. We obtained two epochs of observations in Z-band. Our
results of seeing-matched aperture photometry are tabulated below:
time since burst exposure time seeing magnitude
(hours) (seconds) (arcsec)
4.0 5 x 240 0.8 19.75
22.8 5 x 240 0.7 21.60
The statistical error on the magnitude is typically 0.01, while we
estimate the zeropoint calibration error to be 0.3 magnitudes.
We thus measure a decay for the optical counterpart of 1.85 +/- 0.01
magnitude over 18.8 hours, with an average decay index of 0.98 +/- 0.01.