Relic galaxies: where are they?

TL;DR

This study investigates the locations of relic galaxies, finding evidence from simulations and observations that such galaxies are more likely to be found in high-density environments like galaxy clusters.

Contribution

The paper combines simulation and observational data to show that relic galaxies are more commonly located in dense environments, addressing the question of their typical locations.

Findings

Relic galaxies are more likely in high-density environments.

NGC 1277 is located in a rich galaxy cluster.

Simulations and observations agree on relics' preferred locations.

Abstract

The finding that massive galaxies grow with cosmic time fired the starting gun for the search of objects which could have survived up to the present day without suffering substantial changes (neither in their structures, neither in their stellar populations). Nevertheless, and despite the community efforts, up to now only one firm candidate to be considered one of these relics is known: NGC 1277. Curiously, this galaxy is located at the centre of one of the most rich near galaxy clusters: Perseus. Is its location a matter of chance? Should relic hunters focus their search on galaxy clusters? In order to reply this question, we have performed a simultaneous and analogous analysis using simulations (Millennium I-WMAP7) and observations (New York University Value-Added Galaxy Catalogue). Our results in both frameworks agree: it is more probable to find relics in high density environments.