Halo Occupation Distributions of Moderate X-ray AGNs through Major and Minor Mergers in a $\Lambda$-CDM Cosmology

TL;DR

This study models the halo occupation distribution of moderate X-ray AGNs in a $b5$-CDM universe, revealing that minor mergers significantly contribute to AGN activity, aligning simulations with observations.

Contribution

It introduces a simple merging activity-based model for HODs of X-ray AGNs, highlighting the role of minor mergers in AGN activity, which was previously underappreciated.

Findings

Simulated HODs match observed distributions of mXAGNs.

Minor mergers significantly influence AGN activity.

Major and minor merger models produce consistent HODs.

Abstract

Motivated by recent inferred form of the halo occupation distribution (HOD) of X-ray selected AGNs, in the COSMOS field by Allevato et al. (2012), we investigate the HOD properties of moderate X-ray luminosity Active Galactic Nuclei (mXAGNs) using a simple model based on merging activity between dark matter halos (DMHs) in a $\Lambda$-CDM cosmology. The HODs and number densities of the simulated mXAGNs at $z=0.5$, under the above scenarios to compare with Allevato et al. (2012) results. We find that the simulated HODs of major and minor mergers, and the observed for mXAGNs are consistent among them. Our main result is that minor mergers, contrary to what one might expect, can play an important role in activity mAGNs.