Kinematic properties as probes of the evolution of dwarf galaxies in the Virgo cluster

TL;DR

This study investigates the kinematic and morphological properties of dwarf elliptical galaxies in the Virgo cluster, revealing that many are rotationally supported and likely evolved from late-type galaxies through environmental effects.

Contribution

It provides new observational evidence linking the kinematic support and morphology of dwarf galaxies to their evolutionary history in the cluster environment.

Findings

52% of dEs are rotationally supported

Rotationally supported dEs are younger (~3 Gyr) and often in outskirts or field

Non-rotating dEs are mostly in the cluster core and likely have different origins

Abstract

We present new observational results on the kinematical, morphological, and stellar population properties of a sample of 21 dEs located both in the Virgo cluster and in the field, which show that 52% of the dEs i) are rotationally supported, ii) exhibit structural signs of typical rotating systems such as discs, bars or spiral arms, iii) are younger (~3 Gyr) than non-rotating dEs, and iv) are preferentially located either in the outskirts of Virgo or in the field. This evidence is consistent with the idea that rotationally supported dwarfs are late type spirals or irregulars that recently entered the cluster and lost their gas through a ram pressure stripping event, quenching their star formation and becoming dEs through passive evolution. We also find that all, but one, galaxies without photometric hints for hosting discs are pressure supported and are all situated in the inner regions of the cluster. This suggests a different evolution from the rotationally supported systems. Three different scenarios for these non-rotating galaxies are discussed (in situ formation, harassment and ram pressure stripping).