Nature and nurture of early-type dwarf galaxies in low density environments

TL;DR

This study analyzes the stellar populations of 13 dwarf galaxies in low-density environments, revealing they are generally younger, less metal-rich, and less alpha-enhanced than giant ellipticals, with indications of more prolonged star formation histories.

Contribution

It provides new insights into the stellar population parameters of dwarf galaxies in low-density environments and compares them with giant ellipticals, highlighting differences in age, metallicity, and star formation history.

Findings

Dwarfs are younger than giant ellipticals.

Dwarfs are less metal-rich and less alpha-enhanced.

Possible evidence of more prolonged star formation in low-density dwarfs.

Abstract

We study stellar population parameters of a sample of 13 dwarf galaxies located in poor groups of galaxies using high resolution spectra observed with VIMOS at the ESO-VLT. LICK-indices were compared with Simple Stellar Population models to derive ages, metallicities and [alpha/Fe]-ratios. Comparing the dwarfs with a sample of giant ETGs residing in comparable environments we find that the dwarfs are on average younger, less metal-rich, and less enhanced in alpha-elements than giants. Age, Z, and [alpha/Fe] ratios are found to correlate both with velocity dispersion and with morphology. We also find possible evidence that low density environment (LDE) dwarfs experienced more prolonged star formation histories than Coma dwarfs, however, larger samples are needed to draw firm conclusions.