The Chandra COSMOS Legacy Survey: Compton Thick AGN at high redshift

Abstract

The existence of a large population of Compton thick (CT, $N_H>10^{24}c{m}^{-2}$) AGN is a key ingredient of most Cosmic X-ray background synthesis models. However, direct identification of these sources, especially at high redshift, is difficult due to the flux suppression and complex spectral shape produced by CT obscuration. We explored the Chandra COSMOS Legacy point source catalog, comprising 1855 sources, to select via X-ray spectroscopy, a large sample of CT candidates at high redshift. Adopting a physical model to reproduce the toroidal absorber, and a Monte-Carlo sampling method, we selected 67 individual sources with >5% probability of being CT, in the redshift range $0.04<z<3.5$. The sum of the probabilities above $N_H>10^{24}c{m}^{-2}$, gives a total of 41.9 effective CT, corrected for classification bias. We derive number counts in the 2-10 keV band in three redshift bins. The observed logN-logS is consistent with an increase of the intrinsic CT fraction ($f_{CT}$) from $\sim 0.30$ to $\sim 0.55$ from low to high redshift. When rescaled to a common luminosity (log(L${}_{\mathrm{X}}$/erg/s)$=44.5$) we find an increase from $f_{CT}=0.19_{-0.06}^{+0.07}$ to $f_{CT}=0.30_{-0.08}^{+0.10}$ and $f_{CT}=0.49_{-0.11}^{+0.12}$ from low to high z. This evolution can be parametrized as $f_{CT}=0.11_{-0.04}^{+0.05}(1+z{)}^{1.11\pm 0.13}$. Thanks to HST-ACS deep imaging, we find that the fraction of CT AGN in mergers/interacting systems increases with luminosity and redshift and is significantly higher than for non-CT AGN hosts.

15 pages, 13 figures. Published in MNRAS 31 July 2018

References in corpus (28)

• The Cosmic Evolution Survey (COSMOS) -- Overview
• COSMOS Photometric Redshifts with 30-bands for 2-deg2
• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• Toward the Standard Population Synthesis Model of the X-Ray Background: Evolution of X-Ray Luminosity and Absorption Functions of Active Galactic Nuclei Including Compton-Thick Populations
• The Chandra COSMOS Survey, I: Overview and Point Source Catalog
• X-ray spectral properties of AGN in the Chandra Deep Field South
• Absorption Properties and Evolution of Active Galactic Nuclei
• The XMM-Newton wide-field survey in the COSMOS field: I. Survey description
• Obscuration-dependent evolution of Active Galactic Nuclei
• The XMM-Newton wide-field survey in the COSMOS field. The point-like X-ray source catalogue
• CAIXA: a Catalogue of AGN In the XMM-Newton Archive I. Spectral analysis
• The Chandra COSMOS-Legacy survey: Source X-ray spectral properties
• The X-Ray to Mid-Infrared Relation of AGN at High Luminosity
• Reliable Identification of Compton-thick Quasars at z~2: Spitzer Mid-IR spectroscopy of HDF-oMD49
• Compton thick active galactic nuclei in Chandra surveys
• The Hard X-Ray Luminosity Function of High-Redshift ($3<z\lesssim 5$) Active Galactic Nuclei
• XMM-Newton observations of the Lockman Hole: X-ray source catalogue and number counts
• Compton Thick AGN in the XMM-COSMOS survey
• Mapping the average AGN accretion rate in the SFR-M* plane for Herschel selected galaxies at 0<z<2.5
• Compton thick AGN in the NuSTAR era
• Relationship between star formation rate and black hole accretion at z=2: The different contributions in quiescent, normal and starburst galaxies
• Revealing X-ray obscured quasars in SWIRE sources with extreme mid-IR/optical flux ratios
• The NuSTAR Serendipitous Survey: Hunting for The Most Extreme Obscured AGN at >10 keV
• Compton Thick AGN in the 70 Month Swift-BAT All-Sky Hard X-ray Survey: a Bayesian approach
• The NuSTAR Extragalactic Surveys: X-ray spectroscopic analysis of the bright hard-band selected sample
• Type 2 AGN host galaxies in the Chandra-COSMOS Legacy Survey: No Evidence of AGN-driven Quenching
• The NuSTAR Extragalactic Surveys: source catalog and the Compton-thick fraction in the UDS field
• Similar Scaling Relations for the Gas Content of Galaxies across Environments to z ~ 3.5

Cited by in corpus (55)

• The Bolometric Quasar Luminosity Function at z = 0-7
• The Quest for Dual and Binary Supermassive Black Holes: A Multi-Messenger View
• The Accretion History of AGN I: Supermassive Black Hole Population Synthesis Model
• Supermassive Black Holes at High Redshift are Expected to be Obscured by their Massive Host Galaxies' Inter Stellar Medium
• SUPER I. Toward an unbiased study of ionized outflows in z~2 active galactic nuclei: survey overview and sample characterization
• The properties of the AGN torus as revealed from a set of unbiased NuSTAR observations
• Mock catalogs for the extragalactic X-ray sky: simulating AGN surveys with Athena and with the AXIS probe
• A Triple AGN in a Mid-Infrared Selected Late Stage Galaxy Merger
• Spectral Energy Distributions in Three Deep-Drilling Fields of the Vera C. Rubin Observatory Legacy Survey of Space and Time: Source Classification and Galaxy Properties
• Compton-thick AGN in the NuSTAR era III: A systematic study of the torus covering factor
• Piercing Through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields: I. X-ray Spectral and Long-term Variability Analyses
• Properties and Evolution of Dual and Offset AGN in the ASTRID Simulation at $z\sim 2$
• A panchromatic view of infrared quasars: excess star formation and radio emission in the most heavily obscured systems
• The demographics of obscured AGN from X-ray spectroscopy guided by multiwavelength information
• Narrow line AGN selection in CEERS: spectroscopic selection, physical properties, X-ray and radio analysis
• AGN Triality of Triple Mergers: Detection of Faint X-ray Point Sources
• The fundamental plane of black hole activity for low-luminosity radio active galactic nuclei across 1 < z < 4
• Accretion History of AGN II: Constraints on AGN Spectral Parameters using the Cosmic X-ray Background
• X-ray properties and obscured fraction of AGN in the J1030 Chandra field
• NuSTAR and Keck Observations of Heavily Obscured Quasars Selected by WISE
• Comparing the host galaxy ages of X-ray selected AGN in COSMOS: Obscured AGN are associated with older galaxies
• The XMM deep survey in the CDFS XI. X-ray properties of 185 bright sources
• Accretion History of AGN III: Radiative Efficiency and AGN Contribution to Reionization
• SMBH accretion properties of radio-selected AGN out to z~4
• The NuSTAR Extragalactic Survey of the James Webb Space Telescope North Ecliptic Pole Time-Domain Field
• Fast SMBH growth in the SPT2349--56 protocluster at $z=4.3$
• Piercing through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields. II. Are Highly Obscured AGNs the Missing Link in the Merger-Triggered AGN-Galaxy Coevolution Models?
• The Most Obscured AGNs in the XMM-SERVS Fields
• Surveys of the Cosmic X-ray Background
• Joint Survey Processing I: Compact oddballs in the COSMOS field -- low-luminosity Quasars at z > 6?
• A big red dot at cosmic noon
• JADES -- The small blue bump in GN-z11: insights into the nuclear region of a galaxy at z=10.6
• BASS. XLIX. Characterization of highly luminous and obscured AGNs: local X-ray and [NeV]$\lambda$3426 emission in comparison with the high-redshift Universe
• Compton-thick active galactic nuclei from the 7 Ms observation in the Chandra Deep Field South
• COSMOS2020: Investigating the AGN-obscured accretion phase at $z\sim 1$ via [NeV] selection
• Multi-wavelength Selected Compton-thick AGNs in Chandra Deep Field-South Survey
• Chandra Observations of Excess Fe K$\alpha$ Line Emission in Galaxies with High Star Formation Rates: X-ray Reflection on Galaxy Scales?
• Contribution of Flares from Tidal Disruption of Stars to high-redshift AGN
• X-ray spectral properties of dust-obscured galaxies in the XMM-SERVS coverage of the XMM-LSS field
• Redshift identification of X-ray selected active galactic nuclei in the J1030 field: searching for large-scale structures and high-redshift sources
• Large-scale clustering of buried X-ray AGN: Trends in AGN obscuration and redshift evolution
• Measuring the Cosmic X-ray Background accurately
• Winds of change: the nuclear and galaxy-scale outflows and the X-ray variability of 2MASS 0918+2117
• Warm Gas in the Vicinity of a Supermassive Black hole 13 Billion Years Ago
• X-Ray Redshifts of Obscured Chandra Source Catalog AGN
• LBT-MODS spectroscopy of high-redshift candidates in the Chandra J1030 field. A newly discovered z$\sim$2.8 large scale structure
• Chandra Follow-up Observations of Swift-BAT-selected AGNs III
• X-ray Absorption and Reprocessing in the $z\sim 2.5$ Lensed Quasar 2MASS J1042+1641
• BASS XLV: Quantifying AGN Selection Effects in the Chandra COSMOS-Legacy Survey with BASS
• A study of 1000 galaxies with unusually young and massive stars in the SDSS: a search for hidden black holes
• Identifying Compton-thick active galactic nuclei in the COSMOS. II. Searching among mid-infrared selected AGNs
• Merger or Not: Accounting for Human Biases in Identifying Galactic Merger Signatures
• The $N_H$ Distribution of Hard X-ray Selected AGN in the NEP Field
• Selection of Compton-thick AGN from a hard photometric sample using XMM-Newton observations
• Chandra Follow-up Observations of Swift-BAT-selected AGNs II