Far-ultraviolet photometry of globular clusters with ANS. III - Globular cluster ages
Abstract
Synthesis of far-ultraviolet energy distributions of globular clusters in the ANS system is carried out, using the isochrones and luminosity functions of Ciardullo and Demarque (1977), the theoretical ANS colors of the Kurucz (1977) model atmospheres, and concentrating on the question of cluster ages. The contribution of the horizontal branch stars to the integrated energy distribution is determined. Results for the cluster ages are presented in two ways: (1) individual cluster ages are derived for the whole sample of well-observed clusters, including both early and late HB types, and (2) an upper limit for the age spread is determined for the restricted group of low-metallicity clusters with blue horizontal branches. It is concluded that the volume containing the low-metallicity clusters has collapsed on a dynamical time-scale.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 1981
- DOI:
- 10.1093/mnras/196.4.823
- Bibcode:
- 1981MNRAS.196..823V
- Keywords:
-
- Astronomical Netherlands Satellite;
- Globular Clusters;
- Hertzsprung-Russell Diagram;
- Horizontal Branch Stars;
- Stellar Evolution;
- Ultraviolet Photometry;
- Atmospheric Models;
- Far Ultraviolet Radiation;
- Galactic Evolution;
- Spectral Energy Distribution;
- Star Distribution;
- Astronomy