The X-ray Zurich Environmental Study (X-ZENS). I. Chandra and XMM-Newton observations of AGNs in galaxies in nearby groups

Abstract

We describe X-ray observations with Chandra and XMM-Newton of 18 galaxy groups (M_group ~ 1-6x10^13 Msolar, z~0.05) from the Zurich Environmental Study (ZENS). We aim to establish the frequency and properties, unaffected by host galaxy dilution and obscuration, of AGNs in central and satellite galaxy members, also as a function of halo-centric distance. X-ray point-source detections are reported for 22 of 177 observed galaxies, down to a limit of f_(0.5-8 keV) ~ 5x10^-15 erg cm^-2 s^-1, corresponding to a limiting luminosity of L_(0.5-8 keV)~3x10^40 erg s^-1. With the majority of the X-ray sources attributed to AGNs of low-to-moderate levels (L/L_Edd>~10^-4), we discuss the detection rate in the context of the occupation of AGNs to halos of this mass scale and redshift, and compare the structural/morphological properties between AGN-active and non-active galaxies of different rank and location within the group halos. We see a slight tendency for AGN hosts to have either relatively brighter/denser disks (or relatively fainter/diffuse bulges) than non-active galaxies of similar mass. At galaxy mass scales <10^11 Msolar, central galaxies appear to be a factor ~4 more likely to host AGNs than satellite galaxies of similar mass. This effect, coupled with the tendency for AGNs to reside in massive galaxies, explains the (weak) trend for AGNs to be preferentially found in the inner regions of groups, with no detectable trend with halo-centric distance in the frequency of AGNs within the satellite population. Finally, our data support other analyses in finding that the rate of decline with redshift of AGN activity in groups matches that of the global AGN population, indicating that either AGNs occur preferentially in groups, or that the evolution rate is independent of halo mass. These trends are of potential importance, and require X-ray coverage of a larger sample to be solidly confirmed.

18 pages, 13 figures, submitted to The Astrophysical Journal, this is a revised version that addresses the referee's comments

References in corpus (20)

• The Host Galaxies and Classification of Active Galactic Nuclei
• The Cosmic Evolution Survey (COSMOS) -- Overview
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• A Catalog of Quasar Properties from SDSS DR7
• Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties
• Dwarf Galaxies with Optical Signatures of Active Massive Black Holes
• The Importance of Satellite Quenching for the Build-Up of the Red Sequence of Present Day Galaxies
• The XMM-Newton wide-field survey in the COSMOS field: VI. Statistical properties of clusters of galaxies
• The Luminosity Function of X-ray Selected Active Galactic Nuclei: Evolution of Supermassive Black Holes at High Redshift
• Properties of Galaxy Groups in the SDSS: II.- AGN Feedback and Star Formation Truncation
• The clustering of narrow-line AGN in the local Universe
• AEGIS: Host Galaxy Morphologies of X-ray and Infrared-selected AGN at 0.2 < z < 1.2
• Spectroscopic Confirmation of a Large AGN Population in Clusters of Galaxies
• The XMM-Newton Serendipitous Survey. VI. The X-ray Luminosity Function
• The Distribution of AGN in Clusters of Galaxies
• Tracing the Mass-Dependent Star Formation History of Late-Type Galaxies using X-ray Emission: Results from the Chandra Deep Fields
• The X-ray Properties of Early-Type Galaxies in the Extended Chandra Deep Field-South
• Unveiling a population of galaxies harboring low-mass black holes with X-rays
• The WIRCAM Deep Infrared Cluster Survey I: Groups and Clusters at z > 1.1
• X-ray selected AGN in groups at redshifts z~1

Cited by in corpus (6)

• The Swift/BAT AGN Spectroscopic Survey -- IX. The Clustering Environments of an Unbiased Sample of Local AGN
• The Dependence of AGN Activity on Environment in SDSS
• Changing Ionization Conditions in SDSS Galaxies with AGN as a Function of Environment from Pairs to Clusters
• The COS-AGN survey: Revealing the nature of circum-galactic gas around hosts of active galactic nuclei
• Multiple AGN in the crowded field of the compact group SDSSJ0959+1259
• The X-Ray Zurich Environmental Study (X-ZENS). II. X-ray Observations of the Diffuse Intragroup Medium in Galaxy Groups