GCN Circular 498
Subject
GRB 991216 Optical Observations
Date
1999-12-19T12:15:14Z (25 years ago)
From
Brian Lindgren Jensen at U.of Copenhagen <brian_j@astro.ku.dk>
B. L. Jensen, H. Pedersen, J. Hjorth, J. Pritchard (U. of Copenhagen),
T. Abbott (NOT), A. J. Castro-Tirado (LAEFF-INTA, Madrid), E. Pian
(ITESRE, Bologna), P. Vreeswijk (U. of Amsterdam) and J. Greiner (AIP,
Potsdam) report on behalf of a larger European collaboration:
"We have obtained R-band exposures of the optical counterpart
(GCN #472) using the Danish 1.5m at La Silla (Dec. 18) and the
2.5m Nordic Optical Telescope on La Palma (Dec. 19). When measured
relative to star "A" (GCN #476, #486) we obtain the following
magnitudes:
Date (UT) R Exp FWHM
Dec. 18.11 : 20.12 +-0.1 3x300s 1.8"
Dec. 18.32 : 20.40 +-0.1 3x300s 1.9"
Dec. 19.10 : 20.90 +-0.1 4x300s 1.8"
When analyzed jointly with observations available from GCNs
(excluding the Rc~21.1 from GCN #487) we deduce a power-law
decay index of -1.17+-0.10. The corresponding plot is available at:
http://www.astro.ku.dk/~brian_j/grb/grb991216/ ."