The Contribution of the Obscuring Torus to the X--Ray Spectrum of Seyfert Galaxies: A Test for the Unification Model

Abstract

The presence of an obscuring torus around the nucleus of Seyfert galaxies, as supposed in the popular unification scheme, can strongly modify the X--ray spectrum for both type 1 and 2 Seyfert galaxies. We find that if the torus is Compton thick, it can scatter at small angles a significant fraction of the nuclear radiation, and contribute to the continuum of Seyfert 1 galaxies above $\sim$10 keV, and to the fluorescence iron line at 6.4 keV. At large inclination angles and for large torus column densities, the spectrum is attenuated by photoabsorption and Compton scattering, while the iron fluorescence line produced by the torus can have large equivalent widths. Even after dilution by the continuum scattered by the warm material outside the torus, this iron line could be strong enough to explain the ``cold" component in the spectrum of NGC 1068. We stress that the complex pattern of the predicted variability can be a powerful tool for constraining the parameters of the model, such as the column density of the torus, its inclination and the amount of warm scattering material.

19 pages, Plain Tex, SISSA ref. 175/93/A

Cited by in corpus (257)

• Improved Reflection Models of Black-Hole Accretion Disks: Treating the Angular Distribution of X-rays
• An XMM-Newton survey of broad iron lines in Seyfert galaxies
• ASCA observations of Seyfert 1 galaxies: II. Relativistic Iron K-alpha emission
• Broad iron lines in Active Galactic Nuclei
• An X-ray Spectral Model for Compton-Thick Toroidal Reprocessors
• A 3 dimensional diagnostic diagram for Seyfert 2s: probing X-ray absorption and Compton thickness
• X-ray spectral properties of AGN in the Chandra Deep Field South
• On the X-ray, optical emission line and black hole mass properties of local Seyfert galaxies
• Three years Swift-BAT Survey of AGN: reconciling theory and observations?
• An XMM-Newton spectral survey of 12 micron selected galaxies. I. X-ray data
• Extreme X-ray spectral variability in the Seyfert 2 Galaxy NGC 1365
• X-ray obscuration and obscured AGN in the local universe
• An extended scheme for fitting X-ray data with accretion disk spectra in the strong gravity regime
• Changing look: from Compton-thick to Compton-thin, or the re-birth of fossil AGN
• A Classic Type 2 QSO
• New Spectral Model for Constraining Torus Covering Factors from Broadband X-ray Spectra of Active Galactic Nuclei
• Compton reflection and iron fluorescence in BeppoSAX observations of Seyfert type 1 galaxies
• The X-ray spectra of Compton-thick Seyfert 2 galaxies as seen by BeppoSAX
• Nuclear star formation activity and black hole accretion in nearby Seyfert galaxies
• High-Resolution X-ray Spectroscopy and Modeling of the Absorbing and Emitting Outflow in NGC 3783
• The Nature of the Compton-thick X-ray Reprocessor in NGC 4945
• Evidence for a multizone warm absorber in the XMM-Newton spectrum of Markarian 304
• The Cores of the Fe K$\alpha$ Lines in Active Galactic Nuclei: an Extended Chandra High Energy Grating Sample
• X-ray Insights into the Nature of PHL 1811 Analogs and Weak Emission-Line Quasars: Unification with a Geometrically Thick Accretion Disk?
• On the dependence of the iron K-line profiles with luminosity in Active Galactic Nuclei
• Physical Diagnostics from a Narrow Fe-Kalpha Emission Line Detected by Chandra in the Seyfert 1 Galaxy NGC 5548
• ASCA observations of type-2 Seyfert galaxies: II. The Importance of X-ray Scattering and Reflection
• Variable partial covering and a relativistic iron line in NGC 1365
• X-ray Absorption and Reflection in Active Galactic Nuclei
• Compton Thick AGN: the dark side of the X-ray background
• Seyfert galaxies in the local Universe (z$\le$ 0.1): the average X-ray spectrum as seen by $BeppoSAX$
• The properties of the relativistic iron K-line in NGC 3516
• The XMM-Newton Iron Line Profile of NGC 3783
• X-ray variability and correlations in the two phase disk-corona model for Seyfert galaxies
• NuSTAR catches the unveiling nucleus of NGC 1068
• Testing Comptonization models using BeppoSAX observations of Seyfert 1 galaxies
• The BeppoSAX view of bright Compton-thin Seyfert 2 galaxies
• Study on X-ray Spectra of Obscured AGNs based on Monte Carlo simulation - an interpretation of observed wide-band spectra
• The Origin of the X-ray and Ultraviolet Emission in NGC 7469
• An X-ray Baldwin effect for the narrow Fe K-alpha lines observed in Active Galactic Nuclei
• Penetrating the Deep Cover of Compton Thick Active Galactic Nuclei
• Fe-K line probing of material around the AGN central engine with Suzaku
• The NuSTAR View of Nearby Compton-thick AGN: The Cases of NGC 424, NGC 1320 and IC 2560
• New constraints on the continuum-emission mechanism of AGN: Intensive monitoring of NGC 7469 in the X-ray and ultraviolet
• Compton thick active galactic nuclei in Chandra surveys
• On the origin of the Fe K-alpha line cores in Active Galactic Nuclei
• The evolution of the Compton thick fraction and the nature of obscuration for AGN in the Chandra Deep Field South
• Testing the Seyfert Unification Theory: Chandra HETGS Observations of NGC 1068
• Evidence for Rapid Iron K_alpha Line Flux Variability in MCG--6-30-15
• Compton Thick AGN in the XMM-COSMOS survey
• The relativistic iron line profile in the Seyfert 1 Galaxy IC4329a
• BeppoSAX view of radio-loud Active Galactic Nuclei
• Weak Hard X-ray Emission from Broad Absorption Line Quasars: Evidence for Intrinsic X-ray Weakness
• Fe K emission in the ultraluminous infrared galaxy Arp220
• Determining the covering factor of Compton-thick active galactic nuclei with NuSTAR
• Traces of past activity in the Galactic Centre
• An XMM-Newton observation of the luminous Seyfert 1 galaxy Markarian 509
• The high energy emission line spectrum of NGC 1068
• The XMM-Newton view of PG quasars: II. Properties of the Fe K-alpha line
• Intensive HST, RXTE and ASCA Monitoring of NGC 3516: Evidence Against Thermal Reprocessing
• NuSTAR Reveals Extreme Absorption in z < 0.5 Type 2 Quasars
• Extreme X-ray Iron Lines in Active Galactic Nuclei
• Evidence for a relativistic iron line in GRS 1915+105
• An enshrouded AGN in the merging starburst system Arp~299 revealed by BeppoSAX
• Weak Hard X-ray Emission from Two Broad Absorption Line Quasars Observed with NuSTAR: Compton-thick Absorption or Intrinsic X-ray Weakness?
• Investigation of Dual Active Nuclei, Outflows, Shock-Heated Gas, and Young Star Clusters in Markarian 266
• A panchromatic view of AGN
• NuSTAR Observations of Heavily Obscured Quasars at z ~ 0.5
• Fitting LINER nuclei within the AGN family: A matter of obscuration?
• Revealing the High Energy Emission from the Obscured Seyfert Galaxy MCG -5-23-16 with Suzaku
• High-resolution X-ray imaging and spectroscopy of the core of NGC 4945 with XMM-Newton and Chandra
• On the efficiency of production of the Fe Kalpha emission line in neutral matter
• Long-term X-Ray Spectral Variability in AGN from the Palomar sample observed by Swift
• The soft X-ray excess: NLS1s vs. BLS1s
• The shape of the relativistic iron K-alpha line from MCG6--6-30-15 measured with the Chandra HETGS and RXTE
• The black hole binary V404 Cygni: an obscured AGN analogue
• On the nature of unabsorbed Seyfert 2 galaxies
• Soft X-ray spectroscopy of Compton-thick Seyfert 2 galaxies with BeppoSAX
• Coronal Properties of the Seyfert 1.9 Galaxy MCG -05-23-016 Determined from Hard X-ray Spectroscopy with NuSTAR
• Broadband study of hard X-ray selected absorbed AGN
• X-QUEST: A Comprehensive X-ray Study of Local ULIRGs and QSOs
• Uncovering Obscured Active Galactic Nuclei in Homogeneously Selected Samples of Seyfert 2 Galaxies
• Searching for Compton-thick active galactic nuclei at z~0.1
• Chandra and XMM Observations of Type II Quasars from the SDSS
• A Chandra Observation of M51: Active Nucleus and Nuclear Outflows
• Confirmation of a correlation between the X-ray luminosity and spectral slope of AGNs in the Chandra Deep Fields
• On the Origin of Broad Fe K alpha and Hi H alpha Lines in AGN
• Evidence for relativistic features in the X-ray spectrum of Mrk 335
• X-ray spectral variability of Seyfert 2 galaxies
• The Seyfert-Starburst Connection in X-rays. I. The Data
• Origin of the X-ray disc-reflection steep radial emissivity
• Compact Nuclear Starbursts in Seyfert 2 Galaxies from the CfA and 12 Micron Samples
• A rapidly variable narrow X-ray iron line in Mkn 841
• Drilled by the jet? XMM-Newton discovers a Compton-thick AGN in the GPS galaxy Mkn668
• Buried Black Hole Growth in IR-selected Mergers: New Results from Chandra
• INTEGRAL and XMM-Newton Spectral Studies of NGC 4388
• On the X-ray spectra of luminous, inhomogeneous accretion flows
• Spotting the misaligned outflows in NGC 1068 using X-ray polarimetry
• Witnessing the key early phase of quasar evolution: an obscured AGN pair in the interacting galaxy IRAS 20210+1121
• ASCA Observations of "Type 2" LINERs: Evidence for a Stellar Source of Ionization
• Balancing the Cosmic Energy Budget: The Cosmic X-ray Background, Blazars and the Compton Thick AGN Fraction
• The narrow Fe K$\alpha$ line and the molecular torus in active galactic nuclei - an IR/X-ray view
• Long Term Spectral Variability of Seyfert Galaxies from RXTE Color-Flux Diagrams
• Fe K emission from active galaxies in the COSMOS field
• On variability and spectral distortion of the fluorescent iron lines from black-hole accretion discs
• The Vertical Structure and Ultraviolet Spectrum of X-Ray Irradiated Accretion Disks in Active Galactic Nuclei
• The Compton shoulder of the Fe Kalpha fluorescent emission line in active galactic nuclei
• ASCA Observations of the Ionized Gas in the Seyfert Galaxy NGC 3783
• Mapping the circumnuclear regions of the Circinus galaxy with the Imaging X-ray Polarimetry Explorer
• Faint progenitors of luminous $z\sim 6$ quasars: why don't we see them?
• The history of the iron K-alpha line profile in the Piccinotti AGN ESO198-G24
• Reflected Iron Line From a Source Above a Kerr Black Hole Accretion Disc
• Suzaku View of the Swift/BAT Active Galactic Nuclei (I): Spectral Analysis of Six AGNs and Evidence for Two Types of Obscured Population
• The Soft X-ray Spectrum of Scattering--Dominated AGN
• Deconstructing NGC 7130
• X-ray flux variability of active galactic nuclei observed using NuSTAR
• Constraints on light bending and reflection from the hard X-ray background
• Looking for obscured QSOs in the X-ray emitting ERO population
• A deep X-ray observation of NGC 4258 and its surrounding field
• The dust-gas AGN torus as constrained from X-ray and mid-infrared observations
• Testing the accuracy of reflection-based supermassive black hole spin measurements in AGN
• X-ray Luminosity and Absorption Column Fluctuations in the H2O Maser Galaxy NGC 4258 from Weeks to Years
• X-ray Underluminous Active Galactic Nuclei Relative to Broad Emission Lines in Ultraluminous Infrared Galaxies
• Are the Nuclei of Seyfert 2 Galaxies Viewed Face-On?
• Fe Kαemission from photoionized slabs: the impact of the iron abundance
• The BeppoSAX broad-band spectrum and variability of the Seyfert 1 NGC 3783
• BAT AGN Spectroscopic Survey XXVII: Scattered X-Ray Radiation in Obscured Active Galactic Nuclei
• Delving Into X-ray Obscuration of Type 2 AGN, Near and Far
• Suzaku Observations of the Circinus galaxy
• On the relativistic iron line and soft excess in the Seyfert 1 galaxy Markarian 335
• An X-ray look at the Seyfert 1 Galaxy Mrk 590: XMM-Newton and Chandra reveal complexity in circumnuclear gas
• X-ray spectral properties of Seyfert galaxies and the unification scheme
• Role of emission angular directionality in spin determination of accreting black holes with broad iron line
• Disclosing the true nature of the Sy 2 galaxy NGC 3281: one more Compton-thick source
• Infrared Excess Sources: Compton Thick QSOs, low luminosity Seyferts or starbursts?
• A Simultaneous RXTE and XMM-Newton Observation of the Broad-Line Radio Galaxy 3C 111
• An XMM-Newton observation of the extreme Narrow Line Seyfert 1 Galaxy, Mrk 359
• NuSTAR J033202-2746.8: direct constraints on the Compton reflection in a heavily obscured quasar at z~2
• Accretion and Outflow in the AGN and Starburst of NGC 5135
• RXTE observations of the Seyfert galaxy NGC 5506: evidence for reflection from disk and torus
• Suzaku Observations of Iron Lines and Reflection in AGN
• Impact of reverberation in flared accretion discs on temporal characteristics of X-ray binaries
• The flat X-ray spectrum of the LINER NGC1052
• Insight Into "Changing-Look" AGN Mrk 1018 from the Fe K$\alpha$ Line: The Reprocessing Gas Has Yet to Fully Respond to the Fading of the AGN
• The XMM-Newton view of IRAS 09104+4109: evidence for a changing-look Type 2 quasar?
• Radio morphology-accretion mode link in FRII low-excitation radio galaxies
• XMM-Newton observations of ULIRGs I: A Compton-thick AGN in IRAS19254-7245
• The X-ray Reflectors in the Nucleus of the Seyfert Galaxy NGC 1068
• The circumnuclear X-ray reflectors in NGC 1068 and the Circinus Galaxy
• Identifying high redshift AGNs using X-ray hardness
• INTEGRAL and RXTE Observations of Centaurus A
• A hard look at local, optically-selected, obscured Seyfert galaxies
• An X-ray view of absorbed INTEGRAL AGN
• Wide-band spectroscopy of the Compton thick Seyfert 2 galaxy Mrk 3 with Suzaku
• On the nuclear obscuration of H2O maser galaxies
• Monitoring the Violent Activity from the Inner Accretion Disk of the Seyfert 1.9 Galaxy NGC 2992 with RXTE
• NuSTAR Uncovers an Extremely Local Compton-thick AGN in NGC 4968
• On the nature of the absorber in IRAS 09104+4109: the X-ray and mid-infrared view
• X-ray Emission from Megamaser Galaxy IC 2560
• Black hole spin: theory and observation
• The BeppoSAX view of the X-ray active nucleus of NGC4258
• The reprocessing features in the X-ray spectrum of the NELG MCG-5-23-16
• The effects of relativistic bulk motion of X-ray flares in the corona on the iron Kalpha line in Seyfert 1 galaxies
• Hard X-ray selected giant radio galaxies - I. The X-ray properties and radio connection
• Complex Absorption Hides a Type II QSO in IRAS 13197-1627
• Localizing narrow Fe K$\alpha$ emission within bright AGN
• X-ray redshifts for obscured AGN: a case study in the J1030 deep field
• Weak Reprocessed Features in the Broad Line Radio Galaxy 3C382
• Radio/X-ray monitoring of the broad-line radio galaxy 3C 382. High-energy view with XMM-Newton and NuSTAR
• Accurate classification of 17 AGNs detected with Swift/BAT
• The contribution of AGN to the X-ray background: the effect of iron features
• Hard X-ray spectral variability of the brightest Seyfert AGN in the Swift/BAT sample
• The Cosmic History of Black Hole Growth from Deep Multiwavelength Surveys
• Nature of Compton-thick Active Galactic Nuclei in "Non-merging'' Luminous Infrared Galaxies UGC 2608 and NGC 5135 Revealed with Broadband X-ray Spectroscopy
• A multiwavelength-motivated X-ray model for the Circinus Galaxy
• An X-ray view of the active nucleus in NGC 4258
• 3C 33: another case of photoionized soft X-ray emission in radio galaxies
• IGR J16351-5806: another close by Compton-thick AGN
• XMM-Newton unveils the type 2 nature of the BLRG 3C 445
• On the variability of the iron line in Mrk 841
• XMM-Newton unveils the complex iron K alpha region of Mrk 279
• Heavy absorption and soft X-ray emission lines in the XMM-Newton spectrum of the Type 2 radio-loud quasar 3C 234
• Suzaku observation of the LINER NGC 4102
• Averaging the AGN X-ray spectra from deep Chandra fields
• A quasi-spherical inner accretion flow in Seyfert galaxies ?
• Suzaku reveals X-ray continuum piercing the nuclear absorber in Markarian 231
• The complex iron line in NGC 7469 observed by BeppoSAX
• Contribution of parsec-scale material onto the polarized X-ray spectrum of type-1 Seyfert galaxies
• A candidate of a type-2 QSO at z=0.9: Large X-ray absorption with a strong broad-H-alpha emission line
• A Suzaku observation of the ULIRG IRAS19254-7245: disclosing the AGN component
• A 12-day ASCA Observation of the Narrow-Line Seyfert 1 Galaxy Ton S180: Time-Selected Spectroscopy
• The X-ray variability of Seyfert 1.8/1.9 galaxies
• RXTE and BeppoSAX Observations of MCG -5-23-16: Reflection From Distant Cold Material
• Testing a double AGN hypothesis for Mrk 273
• A Deep 0.3-10 keV Spectrum of the H${}_2$O Maser Galaxy IC 2560
• Reflection at large distance from the central engine in Seyferts
• Inferring the morphology of AGN torus using X-ray spectra: A reliability study
• X-ray spectroscopy of the Compton-thick Seyfert 2 ESO 138-G1
• Relativistic accretion disk reflection in AGN X-ray spectra at z=0.5--4: a study of four \textit{Chandra} deep fields
• A Chandra observation of the H2O megamaser IC2560
• The nature of the absorbing torus in compact Radio Galaxies
• An XMM-Newton observation of the Narrow Line Seyfert 1 Galaxy, Markarian 896
• The Hard X-Ray View of Reflection, Absorption, and the Disk-Jet Connection in the Radio-Loud AGN 3C 33
• High-Energy Spectral Complexity from Thermal Gradients in Black Hole Atmospheres
• Nuclear obscuration in the high-ionization Seyfert 2 galaxy Tol 0109-383
• Obscuring clouds playing hide-and-seek in the Active Nucleus H0557-385
• XMM-Newton observation of the Seyfert 1 ESO 198-G24
• A Puzzling X-Ray Source Found in the chandra Deep Field South
• A New Sample of Obscured AGNs Selected from the XMM-Newton and AKARI Surveys
• The final verdict by XMM-Newton: the X-ray obscured Seyfert galaxy NGC5506 has a broad Fe K-alpha line
• Physical parameters of the torus for the type 2 Seyfert IC 5063 from mid-IR and X-ray simultaneous spectral fitting
• Suzaku observation of the Phoenix Galaxy
• The energy budget for X-ray to infrared reprocessing in Compton-thin and Compton-thick active galaxies
• Close and distant reprocessing media in Mkn509 studied with BeppoSAX
• The hard X-ray view of the low-luminosity blazar in the radio galaxy NGC6251
• The Contribution of Particle Impact to the Production of Fe K Emission from Accreting Black Holes
• Chandra Reveals Heavy Obscuration and Circumnuclear Star Formation in Seyfert 2 Galaxy NGC 4968
• A receding torus model for the Iwasawa-Taniguchi effect for Compton-thick AGN
• The Compton Mirror in NGC 4151
• BeppoSAX view of NGC 526A: a Seyfert 1.9 galaxy with a flat spectrum
• XMM-Newton Detection of a Compton-thick AGN in the 1-Jy ULIRG/LINER F04103-2838
• Variable X-ray Absorption in the Seyfert 2 Galaxy Mrk 348
• Nuclear X-ray properties of the peculiar radio-loud hidden AGN 4C+29.30
• Absorption at the dust sublimation radius and the dichotomy between X-ray and optical classification in the Seyfert galaxy H0557-385
• On the equivalent width of the Fe K$\alpha$ line produced by a dusty absorber in active galactic nuclei
• High Energy Break and Reflection Features in the Seyfert Galaxy MCG+8-11-11
• Iron Fluorescent Line Emission from Black Hole Accretion Disks with Magnetic Reconnection-Heated Corona
• Coronal properties of the luminous radio-quiet quasar QSO B2202$-$209
• X-Ray Spectral Parameters for a Sample of 95 Active Galactic Nuclei
• Rms variability properties of the iron K alpha line in Seyfert galaxies
• The Young, the Old, and the Dusty: Stellar Populations of AGN Hosts
• BASS. XLIX. Characterization of highly luminous and obscured AGNs: local X-ray and [NeV]$\lambda$3426 emission in comparison with the high-redshift Universe
• An X-ray high-frequency quasi-periodic oscillation in NGC 1365
• Multi-wavelength study of NGC 1365: The obscured active nucleus and off-nuclear compact X-ray sources
• RXTE observations of Seyfert-2 galaxies: evidence for spectral variability
• On the Origin of the FeK$\alpha$ Line in the Seyfert 2 Galaxy NGC 7172
• X-ray spectral and timing analysis of the Compton Thick Seyfert 2 galaxy NGC 1068
• The variable ionized absorber in the Seyfert 2 Mrk 348
• Rapid spectral transition of the black hole binary V404 Cyg
• Spectral and polarimetric signatures of X-ray eclipses in AGN
• On the nature of high X-ray luminosities in SDSS galaxies
• X-ray Redshifts for Obscured Active Galactic Nuclei with AXIS Deep and Intermediate Surveys
• The Complex X-ray Obscuration Environment in the Radio Loud Type 2 Quasar 3C 223
• Ray-tracing simulations of the Soft X-ray Scattered Emission in obscured Active Galactic Nuclei
• Superwind evolution: the young starburst-driven wind galaxy NGC 2782
• X-ray view of four high-luminosity Swift/BAT AGN: Unveiling obscuration and reflection with Suzaku
• Neutron Star Radius-to-mass Ratio from Partial Accretion Disc Occultation as Measured through Fe K$\alpha$ Line Profiles
• Chandra Follow-up Observations of Swift-BAT-selected AGNs III
• Seyfert Galaxies and BeppoSAX
• The disk-torus system in active galactic nuclei: possible evidence of highly spinning black holes
• An XSPEC model to explore spectral features from black-hole sources
• Exploring the accretion-ejection geometry of GRS 1915+105 in the obscured state with future X-ray spectro-polarimetry
• Self-consistent population synthesis of AGN from observational constraints in the X-rays
• Detection and Characterization of Quasi-Periodic Oscillations in Seyfert Galaxy NGC 4151
• Simultaneous solution of Kompaneets equation and Radiative Transfer equation in the photon energy range 1 - 125 KeV
• X-ray sources in the 1.75 Ms Ultra Narrow Deep Field observed by XMM-Newton
• A broadband X-ray study of a sample of AGNs with [OIII] measured inclinations