Optical Spectroscopy of X-ray sources in the Extended Chandra Deep Field South

Abstract

We present the first results of our optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South. A total of 339 sources were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. We measured redshifts for 186 X-ray sources, including archival data and a literature search. We find that the AGN host galaxies have on average redder rest-frame optical colors than non-active galaxies, and that they live mostly in the "green valley". The dependence of the fraction of AGN that are obscured on both luminosity and redshift is confirmed at high significance and the observed AGN space density is compared with the expectations from existing luminosity functions. These AGN show a significant difference in the mid-IR to X-ray flux ratio for obscured and unobscured AGN, which can be explained by the effects of dust self-absorption on the former. This difference is larger for lower luminosity sources, which is consistent with the dust opening angle depending on AGN luminosity.

17 pages, 16 figures in emulateapj format. Replaced to match the version accepted by ApJ. Few changes, main conclusions unchanged. Table 2 is now available at http://www.astro.yale.edu/svirani/ecdfs/

References in corpus (29)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• The Cosmic Evolution Survey (COSMOS) -- Overview
• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• Spectral Energy Distributions of Hard X-ray selected AGNs in the XMDS Survey
• AGN Dusty Tori: II. Observational Implications of Clumpiness
• The COSMOS Survey: Hubble Space Telescope / Advanced Camera for Surveys (HST/ACS) Observations and Data Processing
• The All-wavelength Extended Groth Strip International Survey (AEGIS) Data Sets
• X-ray spectral properties of AGN in the Chandra Deep Field South
• The Great Observatories Origins Deep Survey. VLT/FORS2 Spectroscopy in the GOODS-South Field: Part III
• AEGIS: The color-magnitude relation for X-ray selected AGN
• Radiative Transfer Modeling of Three-Dimensional Clumpy AGN Tori and its Application to NGC 1068
• The evolution of the near-IR galaxy Luminosity Function and colour bimodality up to z ~ 2 from the UKIDSS Ultra Deep Survey Early Data Release
• The Evolution of AGN Host Galaxies: From Blue to Red and the Influence of Large-Scale Structures
• The Evolution of Obscuration in AGN
• Do Moderate-Luminosity Active Galactic Nuclei Suppress Star Formation?
• Measuring the Fraction of Obscured Quasars by the Infrared Luminosity of Unobscured Quasars
• Suppression of star formation in early-type galaxies by feedback from supermassive black holes
• AGN dust tori at low and high luminosities
• The mid IR -- hard X-ray correlation in AGN and its implications for dusty torus models
• XMM and Chandra measurements of the AGN intrinsic absorption: dependence on luminosity and redshift
• The role of AGN in the colour transformation of galaxies at redshifts z~1
• The cosmological properties of AGN in the XMM-Newton Hard Bright Survey
• Mid-infrared Properties and Color Selection for X-ray Detected AGN in the MUSYC ECDF-S field
• The Host Galaxies and Black Holes of Typical z~0.5-1.4 AGN
• The small dispersion of the mid IR -- hard X-ray correlation in AGN
• The mid-infrared emission of Seyfert galaxies. A new analysis of ISOCAM data
• "Hidden" Seyfert 2 Galaxies in the Chandra Deep Field North
• ESO Imaging survey: Optical Deep Public Survey
• Can photo-ionization explain the decreasing fraction of X-ray obscured AGN with luminosity?

Cited by in corpus (89)

• The Chandra Deep Field-South Survey: 4 Ms Source Catalogs
• The Chandra Deep Field-South Survey: 7 Ms Source Catalogs
• Host galaxies, clustering, Eddington ratios, and evolution of radio, X-ray, and infrared-selected AGNs
• The Space Density of Compton Thick AGN and the X-ray Background
• An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: The Redshift Distribution and Evolution of Submillimeter Galaxies
• PRIMUS: The dependence of AGN accretion on host stellar mass and color
• The XMM-Newton Wide-Field Survey in the COSMOS field (XMM-COSMOS): demography and multiwavelength properties of obscured and unobscured luminous AGN
• The Multiwavelength Survey by Yale-Chile (MUSYC): Deep Medium-Band optical imaging and high quality 32-band photometric redshifts in the ECDF-S
• The LABOCA survey of the Extended Chandra Deep Field South: A photometric redshift survey of submillimetre galaxies
• Galaxy Zoo: The fundamentally different co-evolution of supermassive black holes and their early- and late-type host galaxies
• Color-Magnitude Relations of Active and Non-Active Galaxies in the Chandra Deep Fields: High-Redshift Constraints and Stellar-Mass Selection Effects
• The Relation between Black Hole Mass and Host Spheroid Stellar Mass out to z~2
• The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M* plane up to z 2
• FIRST-2MASS Red Quasars: Transitional Objects Emerging from the Dust
• JADES NIRSpec Initial Data Release for the Hubble Ultra Deep Field: Redshifts and Line Fluxes of Distant Galaxies from the Deepest JWST Cycle 1 NIRSpec Multi-Object Spectroscopy
• The 2 Ms Chandra Deep Field-North Survey and the 250 ks Extended Chandra Deep Field-South Survey: Improved Point-Source Catalogs
• The LABOCA survey of the Extended Chandra Deep Field South: Two modes of star formation in AGN hosts?
• Accretion Rate and the Physical Nature of Unobscured Active Galaxies
• The Obscured Fraction of AGN in the XMM-COSMOS Survey: A Spectral Energy Distribution Perspective
• A Public, K-Selected, Optical-to-Near-Infrared Catalog of the Extended Chandra Deep Field South (ECDFS) from the MUltiwavelength Survey by Yale-Chile (MUSYC)
• BASS XXII: The BASS DR2 AGN Catalog and Data
• The Extended Chandra Deep Field-South Survey: Optical spectroscopy of faint X-ray sources with the VLT and Keck
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: Spectroscopic redshifts
• The VLA Survey of the Chandra Deep Field South. V. Evolution and Luminosity Functions of sub-mJy radio sources and the issue of radio emission in radio-quiet AGN
• Deep 1.1 mm-wavelength imaging of the GOODS-South field by AzTEC/ASTE -- II. Redshift distribution and nature of the submillimetre galaxy population
• AGN Obscuration and the Unified Model
• Linking black-hole growth with host galaxies: The accretion-stellar mass relation and its cosmic evolution
• Ly-alpha Emitting Galaxies at z = 2.1: Stellar Masses, Dust and Star Formation Histories from Spectral Energy Distribution Fitting
• The SIMPLE survey: observations, reduction, and catalog
• Candidate Type II Quasars at 2 < z < 4.3 in the Sloan Digital Sky Survey III
• Supermassive Black Hole Growth in Starburst Galaxies over Cosmic Time: Constraints from the Deepest Chandra Fields
• HELP: The Herschel Extragalactic Legacy Project
• PRIMUS: Infrared and X-ray AGN Selection Techniques at 0.2<z<1.2
• Black-Hole Growth is Mainly Linked to Host-Galaxy Stellar Mass rather than Star Formation Rate
• Dust-Corrected Colors Reveal Bimodality in AGN Host Galaxy Colors at z~1
• Long-Term X-ray Variability of Typical Active Galactic Nuclei in the Distant Universe
• Heavily Obscured AGN in Star-Forming Galaxies at z~2
• A Submillimeter Perspective on the GOODS Fields (SUPER GOODS). III. A Large Sample of ALMA Sources in the GOODS-S
• Unveiling a population of galaxies harboring low-mass black holes with X-rays
• Variability Selected Low-Luminosity Active Galactic Nuclei in the 4 Ms Chandra Deep Field-South
• Luminous WISE-selected Obscured, Unobscured, and Red Quasars in Stripe 82
• PRIMUS: An observationally motivated model to connect the evolution of the AGN and galaxy populations out to z~1
• AGN-Host Galaxy Connection: Morphology and Colours of X-ray Selected AGN at z < 2
• The Chandra Deep Fields: Lifting the Veil on Distant Active Galactic Nuclei and X-Ray Emitting Galaxies
• Sensitive Search For Radio Variables And Transients In The Extended Chandra Deep-Field South
• AGN-Host Connection at 0.5 < z < 2.5: A rapid evolution of AGN fraction in red galaxies during the last 10 Gyr
• Star formation of far-IR AGN and non-AGN galaxies in the green valley: possible implication of AGN positive feedback
• Optimized Photometric Redshifts for the Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey (CANDELS)
• The fraction of AGN in major merger galaxies and its luminosity dependence
• The Host Galaxies of X-ray Quasars Are Not Strong Star Formers
• z~1 Lya Emitters I. The Luminosity Function
• AGN and their host galaxies in the local Universe: two mass independent Eddington ratio distribution functions characterize black hole growth
• Stacked Rest-Frame UV Spectra of Ly$\alpha$-Emitting and Continuum-Selected Galaxies at 2<z<3.5
• The XMM-Newton deep survey in the Chandra Deep Field South. III. Point source catalogue and number counts in the hard X-rays
• The sub-mJy radio population of the E-CDFS: optical and infrared counterpart identification
• The Radio - X-ray relation as a star formation indicator: Results from the VLA--E-CDFS Survey
• Quantifying the anisotropy in the infrared emission of powerful AGN
• BASS XXIX: The near-infrared view of the BLR: the effects of obscuration in BLR characterisation
• Deepest view of AGN X-ray variability with the 7 Ms Chandra Deep Field-South survey
• Lyman alpha Luminosity Functions at Redshift z = 4.5
• The XMM deep survey in the CDF-S II. a 9-20 keV selection of heavily obscured active galaxies at z>1.7
• A Flux-Limited Sample of z~1 Ly-alpha Emitting Galaxies in the CDFS
• Eddington ratio and accretion efficiency in AGN evolution
• The OPTX Project III: X-ray versus Optical Spectral Type for AGNs
• A Deep Ly$\alpha$ Survey in ECDF-S and COSMOS: I. General Properties of Lyman-alpha Emitters at $z\sim 2$
• Spectroscopic identifications of Spitzer sources in the SWIRE/XMM-NEWTON/ELAIS-S1 field: a large fraction of Active Galactic Nuclei with high F(24micron)/F(R) ratio
• The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
• Optical and infrared properties of active galactic nuclei in the Lockman Hole
• Star formation in galaxies hosting AGN: A flat trend of star-formation rate with X-ray luminosity of galaxies hosting AGN in the SCUBA-2 Cosmology Legacy Survey
• Low redshift quasars in the SDSS Stripe 82. Host galaxy colors and close environment
• AGN in dusty hosts: implications for galaxy evolution
• The XMM Deep survey in the CDFS V. Iron K lines from active galactic nuclei in the distant Universe
• Star formation in far-IR AGN and non-AGN galaxies in the green valley. II. Morphological analysis
• X-ray properties of the z ~ 4.5 Lyman-alpha Emitters in the Chandra Deep Field South Region
• Active Galaxy Nuclei at high redshifts: properties and environment of Type 1 and 2 AGNs
• Host galaxy properties and environment of obscured and unobscured X-ray selected Active Galactic Nuclei in the COSMOS survey
• The dependency of AGN infrared color-selection on source luminosity and obscuration: An observational perspective in CDFS and COSMOS
• The contribution of AGN to the sub-mm population
• A More Efficient Search for H2O Megamaser Galaxies : The Power of the X-ray and Mid-infrared Photometry
• Inclination-Dependent AGN Flux Profiles From Strong Lensing of the Kerr Space-Time
• Understanding AGN-host connection in partially obscured active galactic nuclei. Part III: Properties of ROSAT-selected SDSS AGNs
• The VMC Survey -- XLIX. Discovery of a population of quasars dominated by nuclear dust emission behind the Magellanic Clouds
• Color dependence of clustering of massive galaxies at 0.5$\le z\le$2.5: similar spatial distributions between green valley galaxies and AGNs
• Environment of $1\le z\le 2$ obscured and unobscured AGNs in the Extended Chandra Deep Field South
• The XMM deep survey in the CDF-S. X. X-ray variability of bright sources
• Spitzer's View of the Candidate Cluster and Protocluster Catalog (CCPC)
• Identifying clustering at high redshift through actively star-forming galaxies
• The cosmic environment overtakes the local density in shaping galaxy star formation
• A multiwavelength study of near- and mid-infrared selected galaxies at high redshift: ERGs, AGN-identification and the contribution from dust