AGN-Host Galaxy Connection: Morphology and Colours of X-ray Selected AGN at z < 2

TL;DR

This study investigates the relationship between AGN and their host galaxies' morphology and colours at redshifts below 2, using deep X-ray and optical data to understand AGN fueling and evolution.

Contribution

It introduces a new morphological classification method (galSVM) for high-redshift, low-resolution data and analyzes the connection between galaxy properties and X-ray characteristics.

Findings

Morphology and colours vary with redshift and X-ray properties.

The study identifies distinct regions in colour-magnitude diagrams linked to AGN populations.

Results support models of galaxy evolution influenced by AGN activity.

Abstract

The connection between AGN and their host galaxies has been widely studied over recent years, showing it to be of great importance for providing answers to some fundamental questions related with AGN fueling mechanisms, their formation and evolution. Using X-ray and one of the deepest broad-band optical data sets, we studied morphology and colours in relationship with X-ray properties for sources at redshifts z < 2.0, using a sample of 262 AGN in the Subaru/XMM-Newton Deep Survey (SXDS). Morphological classification was obtained using the galSVM code, one of the new methods useful especially when dealing with high-redshift sources and low-resolution data. Colour-magnitude diagrams were studied in relationship with redshift, morphology, X-ray obscuration, and X-ray-to-optical flux ratio. Finally, the significance of different regions was analysed on colour-magnitude diagrams, relating the observed properties of AGN populations with some models of their formation and evolution.