The Evolution and Environments of X-ray Emitting Active Galactic Nuclei in High-Redshift Large-Scale Structures

Abstract

We use deep Chandra imaging and an extensive optical spectroscopy campaign on the Keck 10-m telescopes to study the properties of X-ray point sources in five large-scale structures at redshifts of z ~ 0.7-0.9. We first study X-ray point sources using the statistical measure of cumulative source counts, finding that the measured overdensities are consistent with previous results, but we recommend caution in overestimating the precision of the technique. Optical spectroscopy of objects matched to X-ray point sources confirms a total of 27 AGN within the five structures, and we find that their host galaxies tend to be located away from dense cluster cores. More than 36% of host galaxies are located in the `green valley', which suggests they are a transitional population. Based on analysis of OII and Hd line strengths, the average spectral properties of the AGN host galaxies in all structures indicate either on-going star formation or a starburst within ~ 1 Gyr, and the host galaxies are younger than the average galaxy in the parent population. These results indicate a clear connection between starburst and nuclear activity. We use composite spectra of the spectroscopically confirmed members in each structure to separate them based on a measure of the overall evolutionary state of their constituent galaxies. We define structures as having more evolved populations if their average galaxy has lower EW(OII) and EW(Hd). The AGN in the more evolved structures have lower rest-frame 0.5-8 keV X-ray luminosities (all below 10^43.3 erg s^-1) and longer times since a starburst than those in the less evolved structures, suggesting that the peak of both star formation and AGN activity has occurred at earlier times. With the wide range of evolutionary states and timeframes in the structures, we use our results to analyze the evolution of X-ray AGN and evaluate potential triggering mechanisms.

29 pages, 13 figures

References in corpus (22)

• Heating Hot Atmospheres with Active Galactic Nuclei
• A Semi-Analytic Model for the Co-evolution of Galaxies, Black Holes, and Active Galactic Nuclei
• A Close Look at Star Formation around Active Galactic Nuclei
• Absorption Properties and Evolution of Active Galactic Nuclei
• A synthesis model for AGN evolution: supermassive black holes growth and feedback modes
• Fueling Low-Level AGN Activity Through the Stochastic Accretion of Cold Gas
• AEGIS: The color-magnitude relation for X-ray selected AGN
• The Evolution of AGN Host Galaxies: From Blue to Red and the Influence of Large-Scale Structures
• Chandra Multiwavelength Project X-ray Point Source Catalog
• AEGIS: Host Galaxy Morphologies of X-ray and Infrared-selected AGN at 0.2 < z < 1.2
• AEGIS: Enhancement of Dust-enshrouded Star Formation in Close Galaxy Pairs and Merging Galaxies up to z ~ 1
• The role of AGN in the colour transformation of galaxies at redshifts z~1
• The Distribution of AGN in Clusters of Galaxies
• The Observations of Redshift Evolution in Large Scale Environments (ORELSE) Survey : I. The Survey Design and First Results on Cl 0023+0423 at z = 0.84 and RX J1821.6+6827 at z = 0.82
• Dust-Corrected Colors Reveal Bimodality in AGN Host Galaxy Colors at z~1
• First Measurement of a Rapid Increase in the AGN Fraction in High-Redshift Clusters of Galaxies
• The Complex Structure of the Cl 1604 Supercluster at z~0.9
• Environmental dependence of AGN activity in the supercluster A901/2
• Serendipitous Discovery of an Overdensity of Lyman-Alpha Emitters at z~4.8 in the Cl1604 Supercluster Field
• Chandra Observations of the Cl1604 Supercluster at z=0.9: Evidence for an Overdensity of Active Galactic Nuclei
• The Nature of Blue Early-Type Galaxies in the Goods Fields
• Properties of Galaxies Hosting X-ray Selected Active Galactic Nuclei in the Cl1604 Supercluster at z=0.9

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• The Cluster and Field Galaxy AGN Fraction at z = 1 to 1.5: Evidence for a Reversal of the Local Anticorrelation Between Environment and AGN Fraction
• LoCuSS: A Dynamical Analysis of X-ray AGN in Local Clusters
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• Chronos and Kairos: Mosfire Observations of Post-Starburst Galaxies in z~1 Clusters and Groups
• The Evolution of Active Galactic Nuclei in Clusters of Galaxies from the Dark Energy Survey
• Chandra survey in the AKARI North Ecliptic Pole Deep Field. I. X-ray data, point-like source catalog, sensitivity maps, and number counts
• Hidden Starbursts and Active Galactic Nuclei at 0<z<4 from the Herschel-VVDS-CFHTLS-D1 Field: Inferences on Coevolution and Feedback
• The Violent Youth of Bright and Massive Cluster Galaxies and their Maturation over 7 Billion Years
• Establishing a New Technique for Discovering Large-Scale Structure Using the ORELSE Survey
• The Properties of Radio Galaxies and the Effect of Environment in Large Scale Structures at $z\sim 1$
• Implications of the Environments of Radio-detected AGN in a Complex Protostructure at z$\sim$3.3
• The evolution of the AGN content in groups up to z~1
• AGN triggering in the infall regions of distant X-ray luminous galaxy clusters at 0.9 < z <~ 1.6
• X-Ray Emitting Active Galactic Nuclei from z = 0.6-1.3 in the Intermediate and High-Density Environments of the ORELSE Survey
• Evaluating Tests of Virialization and Substructure Using Galaxy Clusters in the ORELSE Survey
• The X-ray-Optical Relations for Nine Clusters at z = 0.7-1.1
• Possible Evidence of the Radio AGN Quenching of Neighboring Galaxies at z $\sim$ 1
• The Properties of Radio and Mid-infrared Detected Galaxies and the Effect of Environment on the Co-evolution of AGN and Star Formation at $z\sim 1$
• Extended radio AGN at z ~ 1 in the ORELSE survey: The confining effect of dense environments
• Spectroscopic characterization of the protocluster of galaxies around 7C 1756+6520 at z ~ 1.4