The Globular Clusters of the Dwarf Elliptical Galaxies NGC 147, NGC 185, and NGC 205. I. Abundances
Abstract
Spectra have been obtained for a total of 16 globular clusters associated with the M31 dE companion galaxies NGC 147, NGC 185, and NGC 205. An analysis of line strengths relative to similar spectra of galactic globular clusters indicates that with a single exception, all the clusters are apparently old and metal-poor. The exception is the cluster NGC 205 Hubble V which lies near the center of this galaxy. It has an earlier type spectrum than the other clusters and is best interpreted as an intermediate-age (age ~1 Gyr) globular cluster analogous to those found in the Magellanic Clouds. For each dE galaxy, the mean abundance of the associated globular clusters is considerably less than that observed or inferred for the corresponding field halo stars, though an abundance range of at least 0.6 dex is present in each cluster system. Similar results have been found for the halo of M31, M87, and for the Fornax dwarf spheroidal galaxy. We thus conclude that the globular cluster systems of these galaxies represent a population that formed at an earlier epoch than that of the bulk of the field stars. It also appears likely that the mean abundance of a globular cluster system increases with increasing parent galaxy luminosity, but at a rather slow rate.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1988
- DOI:
- 10.1086/166826
- Bibcode:
- 1988ApJ...334..159D
- Keywords:
-
- Abundance;
- Dwarf Galaxies;
- Elliptical Galaxies;
- Globular Clusters;
- Astronomical Spectroscopy;
- Stellar Composition;
- Stellar Evolution;
- Astrophysics;
- CLUSTERS: GLOBULAR;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 147;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 185;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 205;
- GALAXIES: STELLAR CONTENT;
- STARS: ABUNDANCES;
- STARS: EVOLUTION