# Two new confirmed massive relic galaxies: red nuggets in the present-day Universe

## TL;DR

This paper confirms two local massive relic galaxies, showing they are untouched survivors from the early universe with properties similar to high-redshift galaxies, and explores how environment influences their evolution.

## Contribution

It identifies and characterizes two new local relic galaxies, providing insights into their formation, evolution, and environmental dependence, and estimates their number density in the universe.

## Key findings

- Both galaxies have old ages (~13 Gyr) and early formation histories.
- Their properties match those of high-redshift massive galaxies.
- Relic galaxy properties vary with environment, affecting their evolution.

## Abstract

We confirm two new local massive relic galaxies, i.e. untouched survivors of the early universe massive population: Mrk1216 and PGC032873. Both show early and peaked formation events within very short timescales (<1 Gyr) and thus old mean mass-weighted ages (~13 Gyr). Their star formation histories remain virtually unchanged out to several effective radii, even when considering the steeper IMF values inferred out to ~3 effective radii. Their morphologies, kinematics and density profiles are like those found in the z>2 massive population, setting them apart of the typical z~0 massive early-type galaxies. We find that there seems to exist a "degree of relic" that is related on how far into the path to become one of these typical z~0 massive galaxies the compact relic has undergone. This path is partly dictated by the environment the galaxy lives in. For galaxies in rich environments, such as the previously reported relic galaxy NGC1277, the most extreme properties (e.g. sizes, short formation timescales, larger super-massive black holes) are expected, while lower density environments will have galaxies with delayed and/or extended star formations, slightly larger sizes and not that extreme black hole masses. The confirmation of 3 relic galaxies up to a distance of 106Mpc implies a lower limit in the number density of these red nuggets in the local universe of 6x10^{-7} Mpc^{3}, which is within the theoretical expectations.