OTELO Survey: Deep BVRI broadband photometry of the Groth strip. II Properties of X-ray Emitters

TL;DR

This study analyzes X-ray sources in the Groth field using multiwavelength data, classifies their properties, and investigates their clustering behavior, revealing correlations between galaxy types and X-ray characteristics.

Contribution

It provides a comprehensive catalog of X-ray emitters with optical counterparts and introduces a novel anticorrelation between X/O ratio and galaxy concentration index.

Findings

Catalog of 340 X-ray emitters with optical counterparts.

First evidence of anticorrelation between X/O ratio and galaxy concentration.

Detected significant angular clustering among X-ray sources.

Abstract

The Groth field is one of the sky regions that will be targeted by the OTELO (OSIRIS Tunable Filter Emission Line Object) survey in the optical 820 nm and 920 nm atmospheric windows. This field has been observed by AEGIS (All-wavelength Extended Groth strip International Survey) covering the full spectral range, from X-rays to radio waves. Chandra X-ray data with total exposure time of 200ksec are analyzed and combined with optical broadband data of the Groth field in order to study a set of structural parameters of the X-ray emitters and its relation with X-ray properties. We processed the raw, public X-ray data using the Chandra Interactive Analysis of Observations and determined and analyzed different structural parameters in order to produce a morphological classification of X-ray sources. Finally, we analyzed the angular clustering of these sources using 2-point correlation functions. We present a catalog of 340 X-ray emitters with optical counterpart. We obtained the number counts and compared them with AEGIS data. Objects have been classified by nuclear type using a diagnostic diagram relating X-ray-to-optical ratio (X/O) to hardness ratio (HR). Also, we combined structural parameters with other X-ray and optical properties, and found for the first time an anticorrelation between the X/O ratio and the Abraham concentration index which might suggest that early type galaxies have lower Eddington rates than those of late type galaxies. A significant positive angular clustering was obtained from a preliminary analysis of 4 subsamples of the X-ray sources catalog. The clustering signal of the opticaly extended counterparts is similar to that of strongly clustered populations like red and very red galaxies, suggesting that the environment plays an important role in AGN phenomena.