On the differences between globular clusters and spheroidal populations in three elliptical galaxies.
Abstract
The globular cluster systems surrounding three additional E galaxies in the Virgo cluster are studied in order to establish the differences between cluster and spheroid characteristics. The colors and the surface density distributions of the two components in M87 are compared. The clusters are found to be bluer than the spheroids over a comparable range of galactocentric distances by an average of 0.31 in (U-R), 0.30 in (U-B), and 0.11 in (B-R). The radial falloff in the globular cluster surface density is found to be less steep than that deduced from surface photometry of the spheroid. The color differences imply a mean metallicity difference of about 0.6 dex in the sense that the globular clusters are more metal-poor than the spheroidal component. It is concluded that the chemical enrichment history of the globular cluster system and of the spheroidal component must have differed, and that the globular clusters are likely to form a component dynamically as well as chemically distinct from the spheroid.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1981
- DOI:
- 10.1086/183511
- Bibcode:
- 1981ApJ...245L...9F
- Keywords:
-
- Astronomical Photometry;
- Density Distribution;
- Elliptical Galaxies;
- Globular Clusters;
- Virgo Galactic Cluster;
- Galactic Evolution;
- Luminous Intensity;
- Stellar Evolution;
- Stellar Mass;
- Astrophysics