The Formation and Evolution of Virgo Cluster Galaxies - II. Stellar Populations

TL;DR

This study investigates the stellar populations of Virgo cluster galaxies, revealing diverse age and metallicity gradients and linking them to galaxy type, structure, and environment, to understand galaxy formation and evolution.

Contribution

It provides detailed, radially-resolved stellar population profiles for Virgo galaxies, analyzing their gradients and environmental dependencies to inform galaxy evolution models.

Findings

Age gradients are flat or positive depending on galaxy type.

Metallicity gradients are consistently negative across types.

Stellar population properties relate to gas content and structural parameters.

Abstract

We use a combination of deep optical and near-infrared light profiles for a morphologically diverse sample of Virgo cluster galaxies to study the radially-resolved stellar populations of cluster galaxies over a wide range of galaxy structure. We find that, in the median, the age gradients of Virgo galaxies are either flat (lenticulars and Sa-Sb spirals) or positive (ellipticals, Sbc+Sc spirals, gas-rich dwarfs, and irregulars), while all galaxy types have a negative median metallicity gradient. Comparison of the galaxy stellar population diagnostics (age, metallicity, and gradients thereof) against structural and environmental parameters also reveals that the ages of gas-rich systems depend mainly on their atomic gas deficiencies. Conversely, the metallicities of Virgo gas-poor galaxies depend on their concentrations, luminosities, and surface brightnesses. The stellar population gradients of all Virgo galaxies exhibit no dependence on either their structure or environment. We interpret these stellar population data for Virgo galaxies in the context of popular formation and evolution scenarios, and suggest that gas-poor giants grew hierarchically (through dissipative starbursts), gas-poor dwarfs have descended from at least two different production channels (e.g., environmental transformation and merging), while spirals formed inside-out, but with star formation in the outskirts of a significant fraction of the population having been quenched due to ram pressure stripping. (Abridged)