The stellar population and metallicity distribution of the Sombrero galaxy

TL;DR

This study analyzes the stellar population and metallicity distribution of the Sombrero galaxy, revealing similarities with elliptical galaxies of comparable luminosity and providing insights into its formation and chemical evolution.

Contribution

First analysis of the stellar content and metallicity distribution in an early type spiral galaxy, comparing it to elliptical galaxies and informing galaxy formation models.

Findings

The MDF of NGC 4594 resembles that of NGC 5128.

The observed field includes the galaxy's bulge and halo.

Results support models of galaxy formation involving accretion and chemical enrichment.

Abstract

Hubble Space Telescope studies of the resolved stellar population of elliptical galaxies have shown that the galaxies form by steady accretion of gas which is all the while forming stars and evolving chemically to a metallicity distribution that is as high as solar composition in the most massive objects that have been analyzed, and much lower for low mass ellipticals. In this paper we study for the first time the stellar content of an early type spiral galaxy, the massive disk galaxy, the Sombrero, NGC 4594. We consider whether the metallicity distribution function (MDF) in the observed field matches that of elliptical galaxies of some luminosity, and what these data imply for the accretion and enrichment model that can be fitted to the MDF. The MDF of NGC 4594 is similar to that of the elliptical galaxy of similar luminosity, NGC 5128. The field we are probing is a combination of the galaxy's bulge and halo.