A Compton-thick AGN at z~5 in the 4 Ms Chandra Deep Field South

Abstract

We report the discovery of a Compton-thick Active Galactic Nucleus (AGN) at z=4.76 in the 4 Ms Chandra Deep Field South. This object was selected as a V-band dropout in HST/ACS images and previously recognized as an AGN from optical spectroscopy. The 4 Ms Chandra observations show a significant (~4.2sigma) X-ray detection at the V-band dropout position. The X-ray source displays a hardness ratio of HR=0.23+-0.24, which, for a source at z~5, is highly suggestive of Compton-thick absorption. The source X-ray spectrum is seen above the background level in the energy range of ~0.9-4 keV, i.e., in the rest-frame energy range of ~5-23 keV. When fixing the photon index to Gamma=1.8, the measured column density is N_H=1.4^{+0.9}_{-0.5} x 10^{24} cm^{-2}, which is Compton-thick. To our knowledge, this is the most distant heavily obscured AGN, confirmed by X-ray spectral analysis, discovered so far. The intrinsic (de-absorbed), rest-frame luminosity in the 2-10 keV band is ~2.5 x 10^{44} erg s^{-1}, which places this object among type-2 quasars. The Spectral Energy Distribution shows that massive star formation is associated with obscured black hole accretion. This system may have then been caught during a major co-eval episode of black hole and stellar mass assembly at early times. The measure of the number density of heavily obscured AGN at high redshifts will be crucial to reconstruct the BH/galaxy evolution history from the beginning.

5 pages, 2 figures. Accepted for publication in ApJ Letters

References in corpus (14)

• X-ray Properties of Black-Hole Binaries
• The synthesis of the cosmic X-ray background in the Chandra and XMM-Newton era
• X-ray spectral properties of AGN in the Chandra Deep Field South
• Multiwavelength study of massive galaxies at z~2. II. Widespread Compton thick AGN and the concurrent growth of black holes and bulges
• The Blast Wave Model for AGN Feedback: Effects on AGN Obscuration
• Weighing the Black Holes in z~2 Submillimeter-Emitting Galaxies Hosting Active Galactic Nuclei
• The XMM Deep survey in the CDFS I. First results on heavily obscured AGN
• Reliable Identification of Compton-thick Quasars at z~2: Spitzer Mid-IR spectroscopy of HDF-oMD49
• A submillimetre galaxy at z=4.76 in the LABOCA survey of the Extended Chandra Deep Field South
• High redshift quasars in the COSMOS survey: the space density of z>3 X-ray selected QSOs
• The UDF05 Follow-up of the HUDF: I. The Faint-End Slope of the Lyman-Break Galaxy Population at z~5
• Discovery of strong Iron Kα emitting Compton thick quasars at z=2.5 and 2.9
• The HELLAS2XMM Survey. XII. The infrared/sub-millimeter view of an X-ray selected Type 2 quasar at z=2
• Obscured and powerful AGN and starburst activities at z~3.5

Cited by in corpus (54)

• Dusty Star-Forming Galaxies at High Redshift
• Identifying Luminous AGN in Deep Surveys: Revised IRAC Selection Criteria
• The Chandra Deep Field-South Survey: 4 Ms Source Catalogs
• Cosmic X-ray Surveys of Distant Active Galaxies: The Demographics, Physics, and Ecology of Growing Supermassive Black Holes
• Faint high-redshift AGN in the Chandra Deep Field South: the evolution of the AGN luminosity function and black hole demography
• Are Compton-Thick AGN the Missing Link Between Mergers and Black Hole Growth?
• Deep Silicate absorption features in Compton-thick AGN predominantly arise due to dust in the host galaxy
• ALMA resolves turbulent, rotating [CII] emission in a young starburst galaxy at z=4.8
• A massive stellar bulge in a regularly rotating galaxy 1.2 billion years after the Big Bang
• An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep Field South: The AGN Fraction and X-ray Properties of Submillimeter Galaxies
• The Coevolution of Supermassive Black Holes and Massive Galaxies at High Redshift
• The X-ray Star Formation Story as Told by Lyman Break Galaxies in the 4 Ms CDF-S
• Compton thick active galactic nuclei in Chandra surveys
• The evolution of the Compton thick fraction and the nature of obscuration for AGN in the Chandra Deep Field South
• ALMA reveals a chemically evolved submillimeter galaxy at z=4.76
• The Population of High Redshift AGNs in the Chandra COSMOS survey
• The XMM deep survey in the CDFS IV. Candidate Compton-thick AGN
• Black hole growth in the early Universe is self-regulated and largely hidden from view
• NuSTAR Reveals Extreme Absorption in z < 0.5 Type 2 Quasars
• Supermassive black holes in cosmological simulations II: the AGN population and predictions for upcoming X-ray missions
• ALMA reveals a warm and compact starburst around a heavily obscured supermassive black hole at z=4.75
• A Submillimeter Perspective on the GOODS Fields (SUPER GOODS). III. A Large Sample of ALMA Sources in the GOODS-S
• Lifting the Veil on Obscured Accretion: Active Galactic Nuclei Number Counts and Survey Strategies for Imaging Hard X-ray Missions
• The X-ray emission of z>2.5 active galactic nuclei can be obscured by their host galaxies
• Enhanced [CII] emission in a z=4.76 submillimetre galaxy
• Tracking Down the Source Population Responsible for the Unresolved Cosmic 6-8 keV Background
• Discovery Of Cold, Pristine Gas Possibly Accreting Onto An Overdensity Of Star-Forming Galaxies At Redshift z ~ 1.6
• The Chandra Deep Fields: Lifting the Veil on Distant Active Galactic Nuclei and X-Ray Emitting Galaxies
• Mock catalogs for the extragalactic X-ray sky: simulating AGN surveys with Athena and with the AXIS probe
• The molecular gas content in obscured AGN at z > 1
• Dust and gas content of high-redshift galaxies hosting obscured AGN in the CDF-S
• The 700 ks Chandra Spiderweb Field I: evidence for widespread nuclear activity in the Protocluster
• Spectrum of the unresolved cosmic X ray background: what is unresolved 50 years after its discovery
• Piercing Through Highly Obscured and Compton-thick AGNs in the Chandra Deep Fields: I. X-ray Spectral and Long-term Variability Analyses
• GA-NIFS: Early-stage feedback in a heavily obscured AGN at $z=4.76$
• On the Lx-L6micron ratio as a diagnostic for Compton-thick AGN
• X-ray properties of BzK-selected galaxies in the deepest X-ray fields
• Highlights and Discoveries from the Chandra X-ray Observatory
• The space density of Compton-thick AGN at z~0.8 in the zCOSMOS-Bright Survey
• On the nature of the absorber in IRAS 09104+4109: the X-ray and mid-infrared view
• An Iwasawa-Taniguchi Effect for Compton-thick Active Galactic Nuclei
• The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
• The deep Chandra survey in the SDSS J1030+0524 field
• 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?
• X-ray spectroscopy of the Compton-thick Seyfert 2 ESO 138-G1
• On the Absence of High-Redshift AGNs: Little Growth in the Supermassive Black Hole Population at High Redshifts
• The cold molecular gas in z$\gtrsim$6 quasar host galaxies
• The Most Obscured AGNs in the XMM-SERVS Fields
• On the Evolution of High-Redshift Active Galactic Nuclei
• High-Redshift AGNs and the Next Decade of Chandra and XMM-Newton
• Inferring Compton-thick AGN candidates at z>2 with Chandra using the >8 keV restframe spectral curvature
• Recent developments in the search for Compton-thick AGN
• A unique distant submillimeter galaxy with an X-ray-obscured radio-luminous active galactic nucleus
• Obscured accretion from AGN surveys