Compton Thick AGN in the XMM-COSMOS survey

Abstract

Heavily obscured, Compton Thick (CT, NH>10^24 cm^-2) AGN may represent an important phase in AGN/galaxy co-evolution and are expected to provide a significant contribution to the cosmic X-ray background (CXB). Through direct X-ray spectra analysis, we selected 39 heavily obscured AGN (NH>3x10^23 cm^-2) in the 2 deg^2 XMM-COSMOS survey. After selecting CT AGN based on the fit of a simple absorbed two power law model to the XMM data, the presence of CT AGN was confirmed in 80% of the sources using deeper Chandra data and more complex models. The final sample of CT AGN comprises 10 sources spanning a large range of redshift and luminosity. We collected the multi-wavelength information available for all these sources, in order to study the distribution of SMBH and host properties, such as BH mass (M_BH), Eddington ratio (λ_Edd), stellar mass (M*), specific star formation rate (sSFR) in comparison with a sample of unobscured AGN. We find that highly obscured sources tend to have significantly smaller M_BH and higher λ_edd with respect to unobscured ones, while a weaker evolution in M* is observed. The sSFR of highly obscured sources is consistent with the one observed in the main sequence of star forming galaxies, at all redshift. We also present optical spectra, spectral energy distribution (SED) and morphology for the sample of 10 CT AGN: all the available optical spectra are dominated by the stellar component of the host galaxy, and a highly obscured torus component is needed in the SED of the CT sources. Exploiting the high resolution Hubble-ACS images available, we conclude that these highly obscured sources have a significantly larger merger fraction with respect to other X-ray selected samples of AGN. Finally we discuss implications in the context of AGN/galaxy co-evolutionary models, and compare our results with the predictions of CXB synthesis models.

Revised version after referee comments. Accepted for publication in Astronomy & Astrophysics on 25 November 2014. 23 pages, 2 tables, 16 figures

References in corpus (37)

• 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 simple model to interpret the ultraviolet, optical and infrared emission from galaxies
• COSMOS Photometric Redshifts with 30-bands for 2-deg2
• An Observational Determination of the Bolometric Quasar Luminosity Function
• 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
• Weak Gravitational Lensing with COSMOS: Galaxy Selection and Shape Measurements
• The bulk of the black hole growth since z~1 occurs in a secular universe: No major merger-AGN connection
• X-ray spectral properties of AGN in the Chandra Deep Field South
• Photometric redshift and classification for the XMM-COSMOS sources
• The XMM-Newton wide-field survey in the COSMOS field: I. Survey description
• On the X-ray, optical emission line and black hole mass properties of local Seyfert galaxies
• The XMM-Newton wide-field survey in the COSMOS field. The point-like X-ray source catalogue
• Fueling Low-Level AGN Activity Through the Stochastic Accretion of Cold Gas
• Dust covering factor, silicate emission and star formation in luminous QSOs
• On the origin of soft X-rays in obscured AGN: answers from high-resolution spectroscopy with XMM-Newton
• The Structures of Distant Galaxies - III: The Merger History of over 20,000 Massive Galaxies at z < 1.2
• On the Iwasawa-Taniguchi effect of radio-quiet AGN
• Reliable Identification of Compton-thick Quasars at z~2: Spitzer Mid-IR spectroscopy of HDF-oMD49
• Study on X-ray Spectra of Obscured AGNs based on Monte Carlo simulation - an interpretation of observed wide-band spectra
• The XMM-Newton wide-field survey in the COSMOS field. IV: X-ray spectral properties of Active Galactic Nuclei
• XMM and Chandra measurements of the AGN intrinsic absorption: dependence on luminosity and redshift
• Compton thick active galactic nuclei in Chandra surveys
• Radiation pressure and absorption in AGN: results from a complete unbiased sample from Swift
• The M_BH - M_star relation for X-ray obscured, red QSOs at 1.2< z <2.6
• Relativistic blue- and red-shifted absorption lines in AGNs
• Searching for mid-IR obscured AGN in the CDF-N
• The HELLAS2XMM survey. X. The bolometric output of luminous obscured quasars: The Spitzer perspective
• Search for X-ray occultations in Active Galactic Nuclei
• On the absorption of X-ray bright broad absorption line quasars
• A comparison of the morphological properties between local and z~1 infrared luminous galaxies. Are local and high-z (U)LIRGs different?
• Triggered or Self-Regulated Star Formation within Intermediate Redshift Luminous Infrared Galaxies (I). Morphologies and Spatially Resolved Spectral Energy Distributions
• The XMM-Newton view of IRAS 09104+4109: evidence for a changing-look Type 2 quasar?
• Structures of Local Galaxies Compared to High Redshift Star-forming Galaxies
• Searching for highly obscured AGN in the XMM-Newton serendipitous source catalog

Cited by in corpus (29)

• Obscuration-dependent evolution of Active Galactic Nuclei
• The Chandra COSMOS-Legacy survey: Source X-ray spectral properties
• Detailed Shape and Evolutionary Behavior of the X-ray Luminosity Function of Active Galactic Nuclei
• Galaxy-wide outflows in z$\sim$1.5 luminous obscured QSOs revealed through NIR slit-resolved spectroscopy
• The MOSDEF survey: AGN multi-wavelength identification, selection biases and host galaxy properties
• A hard X-ray view of Luminous and Ultra-luminous Infrared Galaxies in GOALS: I - AGN obscuration along the merger sequence
• Buried AGNs in Advanced Mergers:Mid-infrared color selection as a dual AGN finder
• Multi-wavelength properties of Type 1 and Type 2 AGN Host Galaxies in the Chandra-COSMOS Legacy Survey
• Infrared Selection of Obscured Active Galactic Nuclei in the COSMOS Field
• The NuSTAR Serendipitous Survey: The 40 month Catalog and the Properties of the Distant High Energy X-ray Source Population
• The faint radio sky: VLBA observations of the COSMOS field
• The Chandra Deep Fields: Lifting the Veil on Distant Active Galactic Nuclei and X-Ray Emitting Galaxies
• The NuSTAR Serendipitous Survey: Hunting for The Most Extreme Obscured AGN at >10 keV
• Buried Black Hole Growth in IR-selected Mergers: New Results from Chandra
• Compton Thick AGN in the 70 Month Swift-BAT All-Sky Hard X-ray Survey: a Bayesian approach
• Piercing Through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields: I. X-ray Spectral and Long-term Variability Analyses
• The X-ray View of Merger-Induced AGN Activity at Low Redshift
• A panchromatic view of infrared quasars: excess star formation and radio emission in the most heavily obscured systems
• The NuSTAR Extragalactic Survey: Average broad-band X-ray spectral properties of the NuSTAR detected AGN
• X-ray spectral properties of seven heavily obscured Seyfert 2 galaxies
• Where are Compton-thick radio galaxies? A hard X-ray view of three candidates
• Compton-thick AGN in the NuSTAR era IV: A deep NuSTAR and XMM-Newton view of the candidate Compton thick AGN in ESO 116-G018
• The XMM-Newton survey in the H-ATLAS field
• Broad-band X-ray analysis of local mid-infrared selected Compton-thick AGN candidates
• The composite nature of Dust-Obscured Galaxies (DOGs) at z~2-3 in the COSMOS field: II. The AGN fraction
• Multi-wavelength Selected Compton-thick AGNs in Chandra Deep Field-South Survey
• Warm absorbers: supermassive black hole feeding, and Compton-thick AGN
• Multi-wavelength observations of the triple-peaked AGN Mrk 622
• Inferring Compton-thick AGN candidates at z>2 with Chandra using the >8 keV restframe spectral curvature