The Nuclear Reddening Curve for Active Galactic Nuclei and the Shape of the Infra-Red to X-Ray Spectral Energy Distribution

Abstract

We present extinction curves derived from the broad emission lines and continua of large samples of both radio-loud and radio-quiet AGNs. The curves are significantly flatter in the UV than are curves for the local ISM. The reddening curves for the radio-quiet LBQS quasars are slightly steeper than those of the radio-loud quasars in the UV, probably because of additional reddening by dust further out in the host galaxies of the former. The UV extinction curves for the radio-loud AGNs are very flat. This is explicable with slight modifications to standard MRN dust models: there is a relative lack of small grains in the nuclear dust. Our continuum and broad-emission line reddening curves agree in both shape and amplitude, confirming that the continuum shape is indeed profoundly affected by reddening for all but the bluest AGNs. With correction by our generic extinction curve, all of the radio-loud AGNs have continuous optical-UV spectra consistent with a single shape. We show that radio-quiet AGNs have very similar intrinsic UV to optical shape over orders of magnitude in luminosity. We also argue that radio-loud and radio-quiet AGNs probably share the same underlying continuum shape and that most of the systematic differences between their observed continuum shapes are due to higher nuclear reddening in radio-selected AGNs, and additional reddening from dust further out in the host galaxies in radio-quiet AGNs. Our conclusions have important implications for the modelling of quasar continua and the analysis of quasar demographics.

41 pages, including 6 figures and 3 tables. To appear in ApJ vol. 614, October 20 issue. Some slight wording changes. Some additional references added. Small changes in the model fit in section 6.2, to the analytical fit in the Appendix, and to the tabulated reddening curve in the Appendix

References in corpus (13)

• Red and Reddened Quasars in the Sloan Digital Sky Survey
• Unusual Broad Absorption Line Quasars from the Sloan Digital Sky Survey
• Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies
• The Variable Diffuse Continuum Emission of Broad Line Clouds
• Mid-infrared emission of galactic nuclei: TIMMI2 versus ISO observations and models
• Testing the Seyfert Unification Theory: Chandra HETGS Observations of NGC 1068
• Absorption and Reddening in the Seyfert Galaxy NGC 3227
• Multiwavelength Monitoring of the Narrow-Line Seyfert 1 Galaxy Akn 564. II. Ultraviolet Continuum and Emission-line Variability
• Reddening, Emission-Line, and Intrinsic Absorption Properties in the Narrow-Line Seyfert 1 Galaxy Akn 564
• Associated absorption in radio quasars. I. C IV absorption and the growth of radio sources
• Variability of Active Galactic Nuclei from the Optical to X-ray Regions
• Infrared emission towards 11 years after outburst: Properties of the circumstellar dust
• Thermal Infrared 3--5 $\mu$m Colors of Obscured and Unobscured Active Galactic Nuclei

Cited by in corpus (139)

• The Relationship Between Luminosity and Broad-Line Region Size in Active Galactic Nuclei
• Piecing Together the X-ray Background: Bolometric Corrections for Active Galactic Nuclei
• The Cosmic Evolution of Hard X-ray Selected Active Galactic Nuclei
• Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies
• The Bolometric Quasar Luminosity Function at z = 0-7
• The Radiative Efficiency of Accretion Flows in Individual AGN
• Testing thermal reprocessing in AGN accretion discs
• X-CIGALE: fitting AGN/galaxy SEDs from X-ray to infrared
• A supernova origin for dust in a high-redshift quasar
• The Hard X-ray Spectrum as a Probe for Black-Hole Growth in Radio-Quiet Active Galactic Nuclei
• Soft X-ray and Ultraviolet Emission Relations in Optically Selected AGN Samples
• Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies
• The innermost region of AGN tori: implications from the HST/NICMOS Type 1 point sources and near-IR reverberation
• Analysis of optical Fe II emission in a sample of AGN spectra
• Fitting AGN/galaxy X-ray-to-radio SEDs with CIGALE and improvement of the code
• What broad emission lines tell us about how active galactic nuclei work
• Parsec-scale dust emission from the polar region in the type 2 nucleus of NGC 424
• The FIRST-2MASS Red Quasar Survey II: An anomalously high fraction of LoBALs in searches for dust-reddened quasars
• The Spatial Structure of An Accretion Disk
• The Origin of Fe II Emission in AGN
• Magnetohydrodynamic Simulations of Active Galactic Nucleus Disks and Jets
• Redefining the torus: A unifying view of AGN in the infrared and sub-mm
• Type 1 low z AGN. I. Emission properties
• Modeling optical and UV polarization of AGNs I. Imprints of individual scattering regions
• Optical--to--X-ray emission in low-absorption AGN: Results from the Swift-BAT 9 month catalogue
• The spectral energy distribution of the central parsecs of the nearest AGN
• The UV Continuum of Quasars: Models and SDSS Spectral Slopes
• A population of high-redshift type-2 quasars-I. Selection Criteria and Optical Spectra
• Quasar Accretion Disk Sizes From Continuum Reverberation Mapping From the Dark Energy Survey
• Deciphering the JWST spectrum of a 'little red dot' at $z\sim 4.53$: An obscured AGN and its star-forming host
• Dissecting the active galactic nucleus in Circinus -- II. A thin dusty disc and a polar outflow on parsec scales
• Line Shifts, Broad-Line Region Inflow, and the Feeding of AGNs
• Revealing the heavily obscured AGN population of High Redshift 3CRR Sources with Chandra X-ray Observations
• Polar Dust, Nuclear Obscuration and IR SED Diversity in Type-1 AGNs
• The Optical - Infrared Colors of CORALS QSOs: Searching for Dust Reddening Associated With High Redshift Damped Lyman Alpha Systems
• Mining for Dust in Type 1 Quasars
• Monster in the Dark: The Ultraluminous GRB 080607 and its Dusty Environment
• Modeling the Nuclear Infrared Spectral Energy Distribution of Type II Active Galactic Nuclei
• A New Method for Measuring Extragalactic Distances
• Accretion Disk Temperatures and Continuum Colors in QSOs
• Little Red Dots: Rapidly Growing Black Holes Reddened by Extended Dusty Flows
• Type 1 AGN at low z. III. The optical narrow line ratios
• The Infrared Emission from the Narrow Line Region
• The high activity of 3C 454.3 in autumn 2007. Monitoring by the WEBT during the AGILE detection
• Constraints on the black hole spin in the quasar SDSS J094533.99+100950.1
• SDSS J094533.99+100950.1 - the remarkable weak emission line quasar
• UNCOVER: 404 Error -- Models Not Found for the Triply Imaged Little Red Dot A2744-QSO1
• Super- and sub-Eddington accreting massive black holes: A comparison of slim and thin accretion discs through study of the spectral energy distribution
• Galaxy properties of type 1 and 2 X-ray selected AGN and comparison among different classification criteria
• Evidence that most type 1 AGN are reddened by dust in the host ISM
• Polar dust obscuration in broad-line active galaxies from the XMM-XXL field
• Extinction curve template for intrinsically reddened quasars
• The Baldwin effect in the narrow emission lines of AGNs
• X-ray flux in the SED modelling: An application of X-CIGALE in the XMM-XXL field
• The picture of BLR in 2.5-D FRADO: Dynamics & Geometry
• The efficiency of ionising photon production and the radiation energy balance in compact star-forming galaxies
• Contribution of the accretion disk, hot corona, and obscuring torus to the luminosity of Seyfert galaxies: INTEGRAL and Spitzer observations
• The continuum and narrow line region of the NLS1 galaxy Mrk 766
• Evolution of grain size distribution in high-redshift dusty quasars: Integrating large amounts of dust and unusual extinction curves
• Silicate Dust in Active Galactic Nuclei
• The Case for Optically-Thick High Velocity Broad Line Region Gas in Active Galactic Nuclei
• Anomalously Steep Reddening Law in Quasars: An Exceptional Example Observed in IRAS14026+4341
• Discovery of Polarization Reverberation in NGC 4151
• AGN spectral states from simultaneous UV and X-ray observations by XMM-Newton
• The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548
• A Herschel Study of 24 micron-Selected AGNs and Their Host Galaxies
• Reddening of the BLR and NLR in AGN From a Systematic Analysis of Balmer Decrement
• The Covering Factor of Warm Dust in Quasars: View from WISE All-Sky Data Release
• Hard X-Ray to Radio Multiwavelength SED Analysis of Local U/LIRGs in GOALS Sample with Self-consistent AGN Model Including Polar-dust Component
• Modeling accretion disk emission with generalized temperature profile and its effect on AGN spectral energy distribution
• Probing the nature and origin of dust in the reddened quasar IC 4329A with global modelling from X-ray to infrared
• Fe II emission in active galactic nuclei
• Fundamental differences in the properties of red and blue quasars: measuring the reddening and accretion properties with X-shooter
• Dust Destruction by Charging: A Possible Origin of Grey Extinction Curves of Active Galactic Nuclei
• Optical continuum photometric reverberation mapping of the Seyfert-1 galaxy Mrk509
• Near Infrared Spectra and Intrinsic Luminosities of Candidate Type II Quasars at 2 < z < 3.4
• Monitoring the temperature and reverberation delay of the circumnuclear hot dust in NGC 4151
• Modeling photometric reverberation mapping data for the next generation of big data surveys. Quasar accretion disks sizes with the LSST
• The HELLAS2XMM survey. IX. Spectroscopic identification of super-EROs hosting AGNs
• An Apparent Redshift Dependence of Quasar Continuum: Implication for Cosmic Dust Extinction?
• Dust in Active Galactic Nuclei: Anomalous Silicate to Optical Extinction Ratios?
• On the Optical-to-Silicate Extinction Ratio as a Probe of the Dust Size in Active Galactic Nuclei
• Dust Reverberation of 3C273: torus structure and lag -- luminosity relation
• The polyhedral nature of LINERs: An XMM-Newton view of LINERs in radio galaxies
• From Thin to Thick: The Impact of X-ray Irradiation on Accretion Disks in AGN
• Is the dependence of spectral index on luminosity real in optically selected AGN samples?
• Dust-free starburst galaxies at redshifts $z>10$
• The dust attenuation law in $z\sim 6$ quasars
• Energy distribution of individual quasars from far-UV to X-rays: I. Intrinsic UV hardness and dust opacities
• JWST ERS Program Q3D: The pitfalls of virial BH mass constraints shown in a z = 3 quasar with an ultramassive host
• The Subarcsecond Mid-Infrared View of Local Active Galactic Nuclei. IV. The L- and M-band Imaging Atlas
• Estimating reddening of the continuum and broad-line region of active galactic nuclei: the mean reddening of NGC 5548 and the size of the accretion disc
• No evidence of "gray" dust from composite quasar spectra
• Exploring Active Galactic Nuclei and Little Red Dots with the Obelisk simulation
• The luminosity dependence of quasar UV continuum slope: dust extinction scenario
• The Accuracy of Supermassive Black Hole Masses Determined by the Single-Epoch-Spectrum (Dibai) Method
• Dissecting the active galactic nucleus in Circinus -- III. VLT/FORS2 polarimetry confirms dusty cone illuminated by a tilted accretion disc
• Probing AGN Inner Structure with X-ray Obscured Type 1 AGN
• Broad-band spectral energy distribution of 3000 Angstroem break quasars from the Sloan Digital Sky Survey
• Strong CaII absorption lines in the reddened quasar SDSS J2339$-$0912: Evidence of the collision/merger in the host galaxy?
• The role of grain size in AGN torus dust models
• Dust in the Torus of the AGN Unified Model
• Dusty plasma in active galactic nuclei
• The SOUX AGN Sample: SDSS-XMM-Newton Optical, Ultraviolet and X-ray selected active galactic nuclei spanning a wide range of parameter space -- Sample definition
• Quasars as standard candles VI: spectroscopic validation of the cosmological sample
• X-ray illuminated accretion discs and quasar microlensing disc sizes
• Constraining UV Continuum Slopes of Active Galactic Nuclei With CLOUDY Models of Broad Line Region EUV Emission Lines
• Leaving the dark ages with AMIGA
• Photoionization Modelling of the Giant Broad-Line Region in NGC 3998
• VPMS J1342+2840 - an unusual quasar from the variability and proper motion survey
• Measurement of AGN dust extinction based on the near-infrared flux variability of WISE data
• The VMC Survey -- XLIX. Discovery of a population of quasars dominated by nuclear dust emission behind the Magellanic Clouds
• Dust and the intrinsic spectral index of quasar variations: hints of finite stress at the innermost stable circular orbit
• The Optical Variability of SDSS Quasars from Multi-epoch Spectroscopy. III. A Sudden UV Cutoff in Quasar SDSS J2317+0005
• Dust Extinction towards the Type Ia Supernova 2012cu in NGC 4772
• Probing the innermost dusty structure in AGN with mid-IR and near-IR interferometers
• Extinction law in ultraluminous infrared galaxies at z ~ 1
• Astrophysics in 2005
• The composite X-ray spectrum of 3CRR Quasars
• Updated Picture of the Active Galactic Nuclei with Dusty/Dust-free Gas Structures and Effects of the Radiation Pressure
• Spectral variability studies in Active Galactic Nuclei: Exploring continuum and emission line regions in the age of LSST and JWST
• The physical constraints on a new LoBAL QSO at z=4.82
• Application of the FRADO model of BLR formation to the Seyfert galaxy NGC 5548 and the first step toward determining the Hubble constant
• Spectral Energy Distribution profiles from AGN accretion disc in multi-gap setup
• Modelling Grain Rotational Disruption by Radiative Torques and Extinction of Active Galactic Nuclei
• The Composite Spectral Energy Distribution of Quasars is Surprisingly Universal Since Cosmic Noon
• The unusual UV continuum of quasar Ton 34 and the possibility of crystalline dust absorption
• Detecting quasars at very high redshift with next generation X-ray telescopes
• The 2175 Å~ Bump Features in FeLoBAL Quasars: One Indicator of MW-like Dust in the Nuclear Region of Quasar
• The dynamics of the broad-line region in NGC 3227
• Revisiting the X-ray-to-UV relation of Quasars in the era of all-sky surveys
• The reddest ISO-2MASS quasar
• Exploring the physical properties of Type II Quasar candidates at intermediate redshifts with CIGALE
• A Massive Gas Outflow Outside the Line-of-Sight: Imaging Polarimetry of the Blue Excess Hot Dust Obscured Galaxy W0204-0506
• Intensive X-ray/UVOIR continuum reverberation mapping of the Seyfert AGN MCG+08-11-11
• Early Stages of Dusty Tori: The First Infrared Spectra from a Highly Multiscale Quasar Simulation
• AGN polarization modeling with STOKES
• Modelling the polarization dichotomy of Active Galactic Nuclei
• SMA Observations of the Archetypal Compact Steep-spectrum Radio Source 3C 303.1