What controls the [O III] 5007 line strength in AGN?

Abstract

AGN display an extreme range in the narrow emission line equivalent widths. Specifically, in the PG quasar sample the equivalent width of the narrow [O III] 5007 line has a range of >300, while the broad Hb line, for example, has a range of 10 only. The strength of [O III] 5007 is modulated by the covering factor, CF, of the narrow line region (NLR) gas, its density n_e, and ionization parameter U. To explore which of these factors produces the observed large range in [O III] 5007 strength, we measure the strength of the matching narrow Hb and [O III] 4363 lines, detected in 40 out of the 87 z<0.5 PG quasars in the Boroson & Green sample. The photoionization code CLOUDY is then used to infer CF, n_e, and U in each object, assuming a single uniform emitting zone. We find that the range of CF (~0.02-0.2) contributes about twice as much as the range in both n_e and U towards modulating the strength of the [O III] 5007 line. The CF is inversely correlated with luminosity, but it is not correlated with L_Edd as previously speculated. The single zone [O III] 5007 emitting region is rather compact, having R=40L_44^0.45 pc. These emission lines can also be fit with an extreme two zone model, where [O III] 4363 is mostly emitted by a dense (n_e=10^7) inner zone at R=L_44^0.5 pc, and [O III] 5007 by a low density (n_e=10^3) extended outer zone at R=750L_44^0.34 pc. Such an extended [O III] 5007 emission should be well resolved by HST imaging of luminous AGN. Further constraints on the radial gas distribution in the NLR can be obtained from the spectral shape of the IR continuum emitted by the associated dust.

arXiv commentA note was added in the proofs stage

References in corpus (18)

• Composite Quasar Spectra From the Sloan Digital Sky Survey
• The Soft X-Ray Properties of a Complete Sample of Optically Selected Quasars II. Final Results
• A Composite HST Spectrum of Quasars
• The unusual emission line spectrum of IZw1
• Dusty, Radiation Pressure Dominated Photoionization. I. Model Description, Structure And Grids
• What controls the C IV line profile in active galactic nuclei?
• Dusty, Radiation Pressure Dominated Photoionization. II. Multi-Wavelength Emission Line Diagnostics for Narrow Line Regions
• Near Infrared Spectroscopy of High Redshift Active Galactic Nuclei. I. A Metallicity-Accretion Rate Relationship
• A Composite Extreme Ultraviolet QSO Spectrum from the Far Ultraviolet Spectroscopic Explorer
• Size and Structure of the Narrow-Line Region of Quasars
• Are the Narrow Line Regions in Active Galaxies Dusty and Radiation Pressure Dominated?
• A Hubble Space Telescope Survey of Extended [OIII]5007A Emission in a Far-Infrared Selected Sample of Seyfert Galaxies: Results
• Near Infrared Spectroscopy of High Redshift Active Galactic Nuclei. II. Disappearing Narrow Line Regions and the Role of Accretion
• Locally Optimally-emitting Clouds and the Narrow Emission Lines in Seyfert Galaxies
• The Baldwin Effect and Black Hole Accretion: A Spectral Principal Component Analysis of a Complete QSO Sample
• Evidence for a Physically Compact Narrow-Line Region in the Seyfert 1 Galaxy NGC 5548
• Where is the [O III]4363 emitting region in active galactic nuclei?
• On the Relationship Between the Optical Emission-Line and X-ray Luminosities in Seyfert 1 Galaxies

Cited by in corpus (78)

• Nuclear activity versus star formation: emission-line diagnostics at ultraviolet and optical wavelengths
• Spitzer Quasar and ULIRG evolution study (QUEST): I. The origin of the far infrared continuum of QSOs
• The soft X-ray/NLR connection: a single photoionized medium?
• Dusty Structure Around Type-I Active Galactic Nuclei: Clumpy Torus Narrow Line Region and Near-Nucleus Hot Dust
• Accretion and star formation rates in low redshift type-II active galactic nuclei
• Observations of Feedback from Radio-Quiet Quasars: I. Extents and Morphologies of Ionized Gas Nebulae
• New Indicators for AGN Power: The Correlation Between [O IV] lambda 25.89 micron and Hard X-ray Luminosity for Nearby Seyfert Galaxies
• Extremely Red Quasars in BOSS
• Widespread star formation inside galactic outflows
• The Mid-Infrared High-Ionization Lines from Active Galactic Nuclei and Star-Forming Galaxies
• Type 1 AGN at low z. II. The relative strength of narrow lines and the nature of intermediate type AGN
• The properties of the extended warm ionised gas around low-redshift QSOs and the lack of extended high-velocity outflows
• BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission
• SALT Long-slit Spectroscopy of Luminous Obscured Quasars: An Upper Limit on the Size of the Narrow-Line Region?
• ERQs are the BOSS of Quasar Samples: The Highest-Velocity [OIII] Quasar Outflows
• The Unified Model of Active Galactic Nuclei: II. Evolutionary Connection
• [O III] Equivalent Width and Orientation Effects in Quasars
• First Insights into the ISM at $z>8$ with JWST: Possible Physical Implications of a High [O III]$\lambda 4363$/[O III]$\lambda 5007$
• BAT AGN Spectroscopic Survey II: X-ray Emission and High Ionization Optical Emission Lines
• Ionized outflows in luminous type 2 AGNs at z<0.6: no evidence for significant impact on the host galaxies
• Highly accreting quasars: The SDSS low-redshift catalog
• Chemical abundances of Seyfert 2 AGNs-III. Reducing the oxygen abundance discrepancy
• The Unified Model of Active Galactic Nuclei: I. Non-hidden Broad Line Region Seyfert 2 and Narrow Line Seyfert 1 Galaxies
• The multiwavelength properties of red QSOs -- Evidence for dusty winds as the origin of QSO reddening
• The Origin of Double-peaked Narrow Lines in Active Galactic Nuclei II: Kinematic Classifications for the Population at z < 0.1
• The Diagnostic Potential of JWST in Characterizing Elusive AGNs
• The narrow-line region of narrow-line and broad-line type 1 AGN I. A zone of avoidance in density
• New Methods for Identifying Lyman Continuum Leakers and Reionization-Epoch Analogues
• RefleX: X-ray absorption and reflection in active galactic nuclei for arbitrary geometries
• The Baldwin effect in the narrow emission lines of AGNs
• Kinematics of CIV and [OIII] emission in luminous high-redshift quasars
• The Size-Luminosity Relationship of Quasar Narrow-Line Regions
• [OIII] Emission Line Properties in a New Sample of Heavily Reddened Quasars at $z>2$
• A New Iron Emission Template for Active Galactic Nuclei. I. Optical Template for the H$\beta$ region
• Multi-phase outflows in post starburst E+A galaxies -- II. A direct connection between the neutral and ionized outflow phases
• Constraining the dynamical importance of hot gas and radiation pressure in quasar outflows using emission line ratios
• Blue outliers among intermediate redshift quasars
• Modelling narrow-line regions of active galaxies in the Sloan Digital Sky Survey - I.Sample selection and physical conditions
• Reddening of the BLR and NLR in AGN From a Systematic Analysis of Balmer Decrement
• X-ray imaging of the ionisation cones in NGC 5252
• Broad-band selection, spectroscopic identification, and physical properties of a population of extreme emission line galaxies at 3<z<3.7
• New Method for Exploring Super-Eddington AGNs by Near-infrared Observations
• An FMOS Survey of moderate-luminosity broad-line AGN in COSMOS, SXDS and E-CDF-S
• Theoretical Modeling of Emission-Line galaxies: New Classification Parameters for Mid-Infrared and Optical Spectroscopy
• Stellar and gaseous velocity dispersions in type II AGNs at 0.3<z<0.83 from the Sloan Digital Sky Survey
• Evidence for higher black hole spin in radio-loud quasars
• Uncovering the Spectral Energy Distribution in Active Galaxies Using High Ionization Mid-infrared Emission Lines
• MUSE discovers perpendicular arcs in the inner filament of Cen A
• Quasar emission lines as probes of orientation: implications for disc wind geometries and unification
• Evidence that Emission and Absorption Outflows in Quasars Are Related
• Simultaneous XMM-Newton and HST-COS observation of 1H0419-577: the absorbing and emitting ionized gas
• Strong [O III] Objects Among SDSS Broad-Line Active Galaxies
• The relationship between [OIII]5007A equivalent width and obscuration in AGN
• Do quasar broad-line velocity widths add any information to virial black hole mass estimates?
• The Properties of Low-Redshift FeLoBAL Quasars: III. The Location and Geometry of the Outflows
• The XXL Survey: XXXI. Classification and host galaxy properties of 2.1 GHz ATCA XXL-S radio sources
• The optical emission line spectrum of Mark 110
• The HST view of the innermost narrow line region
• Dusty plasma in active galactic nuclei
• The missing FeII bump in faint JWST AGN: possible evidence for metal-poor broad-line regions at early cosmic times
• [OIII] emission in z=2 quasars with and without Broad Absorption Lines
• Constraints on the densities and temperature of Seyfert 2 NLR
• A Deeply Buried Narrow-Line Seyfert 1 Nucleus Uncovered in Scattered Light
• Spectroscopy of broad absorption line quasars at $3\lesssim z\lesssim 5$ -- I: evidence for quasar winds shaping broad/narrow emission line regions
• A New Physical Picture for AGNs Lacking Optical Emission Lines
• First results from the JWST Early Release Science Program Q3D: Benchmark Comparison of Optical and Mid-IR Tracers of a Dusty, Ionized Red Quasar Wind at z=0.435
• On minor black holes in galactic nuclei
• Jet-powered Outflows in Supermassive Black Hole Binary Candidate SDSS J1048+0055
• The local Universe in the era of large surveys -- II. Multi-wavelength characterisation of activity in nearby S0 galaxies
• Multi-wavelength observations of the triple-peaked AGN Mrk 622
• Temperature Discrepancy with Photoionization Models of the Narrow Line Region
• The luminous infrared composite Seyfert 2 galaxy NGC 7679 through the [O III] 5007 emission line
• Properties of spectrally-defined red QSOs at z = 0.3-1.2
• Shedding the envelope: JWST reveals a kiloparsec-scale [OIII]-weak Balmer shell around a z=7.64 quasar
• Hyper-massive Black Holes have Faint Broad and Narrow Emission Lines
• Optimized Spectral Energy Distribution for Seyfert Galaxies
• Data-driven dissection of emission-line regions in Seyfert galaxies
• The Chemical Evolution of Narrow Emission Line Galaxies: the Key to their Formation Processes