A Population of Compact Elliptical Galaxies Detected with the Virtual Observatory

TL;DR

This paper reports the discovery of 21 compact elliptical galaxies using the Virtual Observatory, supporting their formation through tidal stripping, with properties matching numerical simulations.

Contribution

First large sample of compact elliptical galaxies identified and characterized, providing evidence for their formation via tidal stripping.

Findings

Galaxies exhibit old, metal-rich stellar populations.

Properties align with numerical simulations of tidal stripping.

Supports the tidal stripping formation scenario.

Abstract

Compact elliptical galaxies are characterized by small sizes and high stellar densities. They are thought to form through tidal stripping of massive progenitors. However, only a handful of them were known, preventing us from understanding the role played by this mechanism in galaxy evolution. We present a population of 21 compact elliptical galaxies gathered with the Virtual Observatory. Follow-up spectroscopy and data mining, using high-resolution images and large databases, show that all the galaxies exhibit old metal-rich stellar populations different from those of dwarf elliptical galaxies of similar masses but similar to those of more massive early-type galaxies, supporting the tidal stripping scenario. Their internal properties are reproduced by numerical simulations, which result in compact dynamically hot remnants resembling the galaxies in our sample.