The relation between stellar populations, structure and environment for dwarf elliptical galaxies from the MAGPOP-ITP

Abstract

Dwarf galaxies, as the most numerous type of galaxy, offer the potential to study galaxy formation and evolution in detail in the nearby Universe. Although they seem to be simple systems at first view, they remain poorly understood. In an attempt to alleviate this situation, the MAGPOP EU Research and Training Network embarked on a study of dwarf galaxies named MAGPOP-ITP (Peletier et al., 2007). In this paper, we present the analysis of a sample of 24 dwarf elliptical galaxies (dEs) in the Virgo Cluster and in the field, using optical long-slit spectroscopy. We examine their stellar populations in combination with their light distribution and environment. We confirm and strengthen previous results that dEs are, on average, younger and more metal-poor than normal elliptical galaxies, and that their [alpha/Fe] abundance ratios scatter around solar. This is in accordance with the downsizing picture of galaxy formation where mass is the main driver for the star formation history. We also find new correlations between the luminosity-weighted mean age, the large-scale asymmetry, and the projected Virgocentric distance. We find that environment plays an important role in the termination of the star formation activity by ram pressure stripping of the gas in short timescales, and in the transformation of disky dwarfs to more spheroidal objects by harassment over longer timescales. This points towards a continuing infall scenario for the evolution of dEs.

Accepted for publication in MNRAS: 22 pages, 13 figures and 9 tables

References in corpus (11)

• The origin of dwarf ellipticals in the Virgo cluster
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. III. Subpopulations: distributions, shapes, origins
• Stellar populations of early-type galaxies in different environments II. Ages and metallicities
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. I. On the possible disk nature of bright early-type dwarfs
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. II. Early-type dwarfs with central star formation
• Stellar populations of early-type galaxies in different environments I. Line-strength indices
• Absorption line-strengths of 18 late-type spiral galaxies observed with SAURON
• The NOAO Fundamental Plane Survey - III. Variations in the stellar populations of red-sequence galaxies from the cluster core to the virial radius
• Stellar populations of Globular Clusters in the Elliptical galaxy NGC1407
• Truncated Star Formation in Compact Groups of Galaxies: A Stellar Population Study
• Stellar Population Gradients in Bulges along the Hubble Sequence: I. The Data

Cited by in corpus (5)

• Evolution of dwarf early-type galaxies I. Spatially resolved stellar populations and internal kinematics of Virgo cluster dE/dS0 galaxies
• A spectroscopic survey of dwarf galaxies in the Coma Cluster: Stellar populations, environment and downsizing
• The origin of the mu_e - M_B and Kormendy relations in dwarf elliptical galaxies
• Kinematics and Stellar Populations of Low-Luminosity Early-Type Galaxies in the Abell 496 Cluster
• Bimodality in low luminosity E and S0 galaxies