The lopsided distribution of satellites of isolated central galaxies

TL;DR

This study reveals a statistically significant lopsided distribution of satellite galaxies around isolated central galaxies, influenced by galaxy properties and environment, with implications for galaxy evolution.

Contribution

First simulation-based analysis demonstrating the axis-asymmetry of satellite distributions around isolated galaxies and its dependence on various galaxy and environmental factors.

Findings

Lopsided satellite distribution is statistically significant.

Lopsidedness depends on galaxy mass, color, and environment.

Lopsidedness decreases over cosmic time.

Abstract

Satellites are not randomly distributed around their central galaxies but show polar and planar structures. In this paper, we investigate the axis-asymmetry or lopsidedness of satellite galaxy distributions around isolated galaxies in a hydrodynamic cosmological simulation. We find a statistically significant lopsided signal by studying the angular distribution of the satellite galaxies' projected positions around isolated central galaxies in a two-dimensional plane. The signal is dependent on galaxy mass, color and large-scale environment. Satellites that inhabit low-mass blue hosts, or located further from the hosts show the most lopsided signal. Galaxy systems with massive neighbors exhibit stronger lopsidedness. This satellite axis-asymmetry signal also decreases as the universe evolves. Our findings are in agreement with recent observational results, and they provide a useful perspective for studying galaxy evolution, especially on the satellite accretion, internal evolution and interaction with the cosmic large-scale structure.