The X-ray-to-Optical Properties of Optically-Selected Active Galaxies Over Wide Luminosity and Redshift Ranges

Abstract

We present partial-correlation analyses that examine the strengths of the relationships between L_UV, L_X, Alpha_OX, and redshift for optically-selected AGNs. We extend the work of Strateva et al. (2005), that analyzed optically-selected AGNs from the Sloan Digital Sky Survey (SDSS), by including 52 moderate-luminosity, optically-selected AGNs from the COMBO-17 survey with corresponding deep (~250 ks to 1 Ms) X-ray observations from the Extended Chandra Deep Field-South. The COMBO-17 survey extends ~3 magnitudes deeper than the SDSS and probes the moderate-luminosity AGNs that numerically dominate the AGN population in the Universe. We also include recently published observations of 19 high-redshift, optically-selected AGNs, and 46 luminous, low-redshift AGNs from the Bright Quasar Survey. The full sample used in our analysis consists of 333 AGNs, extending out to z~6, with 293 (88%) having X-ray detections. The sample spans five decades in UV luminosity and four decades in X-ray luminosity. We confirm that Alpha_OX is strongly anti-correlated with L_UV (13.6 sigma), the highest significance found for this relation to date, and find evidence suggesting that the slope of this relation may be dependent on L_UV. We find that no significant correlation exists between Alpha_OX and redshift (1.3 sigma), and constrain the maximum evolution of AGN UV-to-X-ray flux ratios to be less than 30% (1 sigma) out to z=5. Using our sample's high X-ray detection fraction, we also find a significant anti-correlation (3.0 sigma) between Alpha_OX and L_X . We make comparisons to earlier studies on this topic and discuss implications for X-ray vs. optical luminosity functions.

16 pages, 10 figures, emulateapj. Accepted for publication in AJ

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• A Chandra view of Naked Active Galactic Nuclei
• A $Chandra-Swift$ View of Point Sources in Hickson Compact Groups: High AGN fraction but a dearth of strong AGNs
• Supermassive Black Hole Winds in X-rays -- SUBWAYS. III. A population study on ultra-fast outflows
• Chandra Observations of Red Sloan Digital Sky Survey Quasars
• The orientation dependence of quasar spectral energy distributions
• The Reddest DR3 SDSS/XMM Quasars
• The Physical Conditions of the Intrinsic N V Narrow Absorption Line Systems of Three Quasars
• The polyhedral nature of LINERs: An XMM-Newton view of LINERs in radio galaxies
• On the Emergence of Thousands of Absorption Lines in the Quasar PG1411+442: A Clumpy High-Column Density Outflow from the Broad Emission-Line Region?
• Accretion Disc Winds in Tidal Disruption Events: Ultraviolet Spectral Lines as Orientation Indicators
• The Frequency of Intrinsic X-ray Weakness Among Broad Absorption Line Quasars
• The Binary Black Hole Model for Mrk 231 Bites the Dust
• A Joint Model of the X-ray And Infrared Extragalactic Backgrounds: I. Model Construction And First Results
• AGN dust tori: the X-ray-infrared connection
• A Suzaku observation of the ULIRG IRAS19254-7245: disclosing the AGN component
• Is the dependence of spectral index on luminosity real in optically selected AGN samples?
• The Extreme Red Excess in Blazar Ultraviolet Broad Emission Lines
• OMCat: Catalogue of Serendipitous Sources Detected with the XMM-Newton Optical Monitor
• AGN's UV and X-ray luminosities in clumpy accretion flows
• The X-ray properties of typical high-redshift radio-loud quasars
• Discovery of late-time X-ray flare and anomalous emission line enhancement after the nuclear optical outburst in a narrow-line Seyfert 1 Galaxy
• Suzaku Observations of Three FeLoBAL QSOs, SDSS J0943+5417, J1352+4239, and J1723+5553
• X-ray emission from a rapidly accreting narrow-line Seyfert 1 galaxy at z=6.56
• A Rapid and Large-Amplitude X-ray Dimming Event in a z ~ 2.6 Radio-Quiet Quasar
• Investigating the Covering Fraction Distribution of Swift/BAT AGN with X-ray and IR Observations
• Unveiling the Intrinsic X-ray Properties of Broad Absorption Line Quasars with a Relatively Unbiased Sample
• Active galactic nuclei ghosts: A systematic search for faded nuclei
• X-ray and optical properties of Broad Absorption Line Quasars in the Canada-France-Hawaii Telescope Legacy Survey
• The XMM-Newton Survey in the Marano Field I. The X-ray data and optical follow-up
• Chandra X-Ray Observations of Two Unusual BAL Quasars
• AGN and star formation across cosmic time
• The most luminous blue quasars at 3.0<z<3.3. II. CIV/X-ray emission and accretion disc physics
• Estimators of Bolometric Luminosity and Black Hole Mass with Mid-infrared Continuum Luminosities for Dust-obscured Quasars: Prevalence of Dust-obscured SDSS Quasars
• Connecting Low- and High-Redshift Weak Emission-Line Quasars via HST Spectroscopy of Ly$\alpha$ Emission
• Narrow, Intrinsic CIV Absorption in Quasars as it Relates to Outflows, Orientation, and Radio Properties
• X-ray Properties of Young Radio Quasars at z > 4.5
• Exploratory Chandra observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.30
• Forward modeling the multiwavelength properties of Active Galactic Nuclei: application to X-ray and WISE mid-infrared samples
• Quasars as Standard Candles IV. Analysis of the X-ray and UV indicators of the disc-corona relation
• The origin of the soft X-ray excess in the narrow-line Seyfert 1 galaxy SBS 1353+564
• The X-ray Properties of Million Solar Mass Black Holes
• The SRG/eROSITA All-Sky Survey: X-ray beacons at late cosmic dawn
• A Chandra Look at Five of the Broadest Double-Peaked Balmer-Line Emitters
• Strong and Rapid X-ray Variability of the Super-Eddington Accreting Quasar SDSS J081456.10+532533.5
• Discovery of Candidate X-ray Jets in High-Redshift Quasars
• Searching for the most distant blazars with the Fermi Gamma-ray Space Telescope
• UM 625 Revisited: Multiwavelength Study of A Seyfert 1 Galaxy with a Low-mass Black Hole
• XMM-Newton observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.326
• An Unobscured type II quasar candidate: SDSS J012032.19-005501.9
• Infrared Imaging of SDSS Quasars: Implications for the Quasar K correction
• Interaction of the accretion flows in corona and disk near the black hole in AGN
• X-ray and multi-epoch optical/UV investigations of BAL to non-BAL quasar transformations
• On the Anticorrelation Between Galaxy Light Concentration and X-ray-to-Optical Flux Ratio
• Inclination-Dependent AGN Flux Profiles From Strong Lensing of the Kerr Space-Time
• Discovery of the Most-Distant Double-Peaked Emitter at z=1.369
• Evolution of luminosity function and obscuration of AGN: connecting X-ray and Infrared
• The Impact of the CMB on the Evolution of high-z Blazars
• A luminous X-ray transient in SDSS J143359.16+400636.0: a likely tidal disruption event
• Surveys of the Cosmic X-ray Background
• A catalog of optical to X-ray spectral energy distributions of z~2 quasars observed with Swift. I: First results
• No evidence for an Eddington-ratio dependence of X-ray weakness in BALQSOs
• Probing quasar lifetimes with proximate $21$-centimetre absorption in the diffuse intergalactic medium at redshifts $z\ge 6$
• Characterization of AGN and their hosts in the Extended Groth Strip: a multiwavelength analysis
• Constraining the AGN luminosity function from JWST with the X-ray Background
• An X-ray fading, UV brightening QSO at $z\approx 6$
• INTEGRAL observations of the GeV blazar PKS1502+106 and of the hard X-ray bright Seyfert Galaxy Mkn841
• High-Redshift AGNs and the Next Decade of Chandra and XMM-Newton
• The X-ray Spectrum and Spectral Energy Distribution of FIRST J155633.8+351758: a LoBAL Quasar with a Probable Polar Outflow
• An X-ray Survey in SA 57 with XMM-Newton
• Accretion History of AGN: Estimating the Host Galaxy Properties in X-ray Luminous AGN from z=0-3
• The non-linear X-ray/UV relation in active galactic nuclei: contribution of instrumental effects on the X-ray variability
• Quasars as Standard Candles V. Evaluation of a $\le$ 0.06 dex intrinsic dispersion in the LX-LUV relation
• Characterising SMSS J2157--3602, the most luminous known quasar, with accretion disc models
• The X-ray emission of the most luminous 3CR radio sources
• The intrinsic X-ray luminosity distribution of an optically-selected SDSS quasar population
• Euclid preparation. Observational expectations for redshift z<7 active galactic nuclei in the Euclid Wide and Deep surveys
• The composite X-ray spectrum of 3CRR Quasars
• X-ray Insights into the Nature of Quasars with Redshifted Broad Absorption Lines
• Properties and Expected Number Counts of Active Galactic Nuclei and their Hosts in the Far Infrared
• Breaking the rules at $z\simeq$0.45: the rebel case of RBS 1055
• Investigating the complex X-ray spectrum of a broad-line 2MASS red quasar: XMM-Newton observation of FTM 0830+3759
• The X-Rays wind connection in PG 2112+059
• High-energy Emission from Turbulent Electron-ion Coronae of Accreting Black Holes
• Tracing Quasar Narrow-Line Regions Across Redshift: A Library of High S/N Optical Spectra
• X-ray selected BALQSOs
• Detecting quasars at very high redshift with next generation X-ray telescopes
• Distinguishing AGN from starbursts as the origin of double peaked Lyman-Alpha Emitters in the reionization era
• X-ray and Multiwavelength Insights into the Inner Structure of High-Luminosity Disc-Like Emitters
• X-ray selected broad absorption line quasars in SDSS-V: BALs and non-BALs span the same range of X-ray properties
• Quasar spectral energy distribution in EUV restored from associated absorbers: indications to the HeII opacity of the quasar accretion disk wind
• The peculiar optical-UV X-ray spectra of the X-ray weak quasar PG 0043+039
• Radio Scrutiny of the X-ray-Weak Tail of Low-Mass Active Galactic Nuclei: A Novel Signature of High-Eddington Accretion?
• Photometric Selection of type 1 Quasars in the XMM-LSS Field with Machine Learning and the Disk-Corona Connection
• Selected Chapters on Active Galactic Nuclei as Relativistic Systems
• Probing the Wind Component of Radio Emission in Luminous High-Redshift Quasars
• The Dawn of Black Holes
• X-ray Unveiling Events in a z~1.6 Active Galactic Nucleus in the 7 Ms Chandra Deep Field-South
• Revisiting the X-ray-to-UV relation of Quasars in the era of all-sky surveys
• A comparison of cosmological models with high-redshift quasars
• Shedding the envelope: JWST reveals a kiloparsec-scale [OIII]-weak Balmer shell around a z=7.64 quasar
• Association of Optical, Ultraviolet and Soft X-ray excess Emissions in AGNs
• Exploratory X-Ray Monitoring of Luminous Radio-Quiet Quasars at High Redshift: Extended Time-Series Analyses and Stacked Imaging Spectroscopy
• Increasing AGN sample completeness using long-term near-infrared variability
• Early Stages of Dusty Tori: The First Infrared Spectra from a Highly Multiscale Quasar Simulation
• Identifying Compton-thick active galactic nuclei in the COSMOS. II. Searching among mid-infrared selected AGNs
• Strong X-ray Variability of I Zwicky 1: Obscuration from Clumpy Accretion-Disk Winds
• Searching for Axion-like Particles with Active Galactic Nuclei
• Can X-ray Observations Improve Optical-UV-based Accretion-Rate Estimates for Quasars?
• Gemini Near Infrared Spectrograph$-$Distant Quasar Survey: the Chandra View
• The physical relation between disc and coronal emission in quasars
• SRG/eROSITA-SDSS view on the relation between X-ray and UV emission for quasars
• Measuring monster MBHs: maybe mighty, maybe merely massive
• Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67-002813.7