Modelling the formation of today's massive ellipticals

TL;DR

This paper reviews how hierarchical cosmological models, incorporating continuous gas accretion and minor mergers, better explain the formation of massive elliptical galaxies than traditional single-event scenarios.

Contribution

It highlights recent progress in modeling elliptical galaxy formation within hierarchical frameworks, emphasizing a two-phase assembly process.

Findings

Hierarchical models with minor mergers better match observations.

Two-phase formation process is favored for massive ellipticals.

Recent progress improves understanding of galaxy evolution.

Abstract

The discovery of a population of massive, compact and quiescent early-type galaxies has changed the view on plausible formation scenarios for the present day population of elliptical galaxies. Traditionally assumed formation histories dominated by 'single events' like early collapse or major mergers appear to be incomplete and have to be embedded in the context of hierarchical cosmological models with continuous gas accretion and the merging of small stellar systems (minor mergers). Once these processes are consistently taken into account the hierarchical models favor a two-phase assembly process and are in much better shape to capture the observed trends. We review some aspects of recent progress in the field.