Small-scale galaxy clustering in the EAGLE simulation

TL;DR

This paper analyzes small-scale galaxy clustering in the EAGLE simulation, demonstrating good agreement with observations for various galaxy properties but noting some limitations due to resolution.

Contribution

It provides a detailed comparison of EAGLE galaxy clustering with observations, highlighting successes and limitations of the simulation at small scales.

Findings

EAGLE reproduces observed galaxy clustering well for most properties.

Low-mass red galaxies are over-clustered, likely due to resolution issues.

Satellite galaxy distributions in EAGLE match observations.

Abstract

We study present-day galaxy clustering in the EAGLE cosmological hydrodynamical simulation. EAGLE's galaxy formation parameters were calibrated to reproduce the redshift $z=0.1$ galaxy stellar mass function, and the simulation also reproduces galaxy colours well. The simulation volume is too small to correctly sample large-scale fluctuations and we therefore concentrate on scales smaller than a few mega parsecs. We find very good agreement with observed clustering measurements from the Galaxy And Mass Assembly (GAMA) survey, when galaxies are binned by stellar mass, color, or luminosity. However, low-mass red-galaxies are clustered too strongly, which is at least partly due to limited numerical resolution. Apart from this limitation, we conclude that EAGLE galaxies inhabit similar dark matter haloes as observed GAMA galaxies, and that the radial distribution of satellite galaxies as function of stellar mass and colour is similar to that observed as well.