Constraints on the Broad Line Region Properties and Extinction in Local Seyferts

Abstract

We use high spectral resolution (R > 8000) data covering 3800-13000Å to study the physical conditions of the broad line region (BLR) of nine nearby Seyfert 1 galaxies. Up to six broad HI lines are present in each spectrum. A comparison - for the first time using simultaneous optical to near-infrared observations - to photoionisation calculations with our devised simple scheme yields the extinction to the BLR at the same time as determining the density and photon flux, and hence distance from the nucleus, of the emitting gas. This points to a typical density for the HI emitting gas of 10${}^{11}$cm${}^{-3}$ and shows that a significant amount of this gas lies at regions near the dust sublimation radius, consistent with theoretical predictions. We also confirm that in many objects the line ratios are far from case B, the best-fit intrinsic broad-line H$\alpha$/H$\beta$ ratios being in the range 2.5-6.6 as derived with our photoionization modeling scheme. The extinction to the BLR, based on independent estimates from HI and HeII lines, is A${}_V$ $\le$ 3 for Seyfert 1-1.5s, while Seyfert 1.8-1.9s have A${}_V$ in the range 4-8. A comparison of the extinction towards the BLR and narrow line region (NLR) indicates that the structure obscuring the BLR exists on scales smaller than the NLR. This could be the dusty torus, but dusty nuclear spirals or filaments could also be responsible. The ratios between the X-ray absorbing column N${}_H$ and the extinction to the BLR are consistent with the Galactic gas-to-dust ratio if N${}_H$ variations are considered.

arXiv comment19 pages, 14 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society

References in corpus (45)

• The Dust Content and Opacity of Actively Star-Forming Galaxies
• A Simple Model for the Absorption of Starlight by Dust in Galaxies
• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• Revisiting the Unified Model of Active Galactic Nuclei
• Estimating Black Hole Masses in Active Galaxies Using the Halpha Emission Line
• AGN Dusty Tori: II. Observational Implications of Clumpiness
• Automated data reduction workflows for astronomy
• The 2013 Release of Cloudy
• Ubiquitous variability of X-ray absorbing column densities in Seyfert 2 Galaxies
• A Comprehensive Study of 2 000 Narrow Line Seyfert 1 Galaxies from the Sloan Digital Sky Survey: I. The Sample
• Locally Optimally Emitting Clouds and the Origin of Quasar Emission Lines
• The relation between AGN hard X-ray emission and mid-infrared continuum from ISO spectra: Scatter and unification aspects
• The origin of the Broad Line Region in Active Galactic Nuclei
• A diversity of dusty AGN tori: Data release for the VLTI/MIDI AGN Large Program and first results for 23 galaxies
• What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
• An Atlas of Computed Equivalent Widths of Quasar Broad Emission Lines
• Analysis of optical Fe II emission in a sample of AGN spectra
• Broad-line Balmer Decrements in Blue Active Galactic Nuclei
• Hot Graphite Dust and the Infrared Spectral Energy Distribution of Active Galactic Nuclei
• Chandra-HETGS Observations of the Brightest Flare Seen from Sgr A*
• The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783
• A multi-wavelength study of the Seyfert 1 galaxy MCG-6-30-15
• Locally Optimally-Emitting Clouds and the Variable Broad Emission Line Spectrum of NGC 5548
• NuSTAR and XMM-Newton Observations of NGC 1365: Extreme Absorption Variability and a Constant Inner Accretion Disk
• The Swift BAT-detected Seyfert 1 Galaxies: X-ray Broadband Properties and Warm Absorbers
• On the relation of optical obscuration and X-ray absorption in Seyfert galaxies
• Radiation pressure confinement - II. Application to the broad line region in active galactic nuclei
• Obscuration in AGNs: near-infrared luminosity relations and dust colors
• The INTEGRAL Complete Sample of Type 1 AGN
• The case for cases B and C: intrinsic hydrogen line ratios of the broad-line region of active galactic nuclei, reddenings, and accretion disc sizes
• Partially obscured quasars in the Sloan Digital Sky Survey Early Data Release
• A Multi-Wavelength Study of the Nature of Type 1.8/1.9 Seyfert Galaxies
• Short-term emission line and continuum variations in Mrk110
• The central parsecs of active galactic nuclei: challenges to the torus
• Evidence for an intermediate line region in AGN's inner torus region and its evolution from narrow to broad line Seyfert I galaxies
• Long-Term Variability in the Optical Spectrum of the Seyfert Galaxy NGC 2992
• Optical vs. infrared studies of dusty galaxies and AGN: (I) Nebular emission lines
• CIV and CIII] reverberation mapping of the luminous quasar PG 1247+267
• The "red shelf" of the Hb line in the Seyfert 1 galaxies RXS J01177+3637 and HS 0328+05
• AGN Reddening and Ultraviolet Extinction Curves from Hubble Space Telescope Spectra
• Constraints on the outer radius of the broad emission line region of active galactic nuclei
• Dust in Active Galactic Nuclei: Anomalous Silicate to Optical Extinction Ratios?
• The location of the dust causing internal reddening of active galactic nuclei
• New Constraints on the Quasar Broad Emission Line Region
• The X-ray variability and the near-IR to X-ray spectral energy distribution of four low luminosity Seyfert 1 galaxies

Cited by in corpus (34)

• Obscured Active Galactic Nuclei
• Ionized outflows in local luminous AGN: what are the real densities and outflow rates?
• The central parsec of NGC 3783: a rotating broad emission line region, asymmetric hot dust structure, and compact coronal line region
• LLAMA: The $M_{BH}$ - ${\sigma }_{\star }$ Relation of the most luminous local AGNs
• The Interplay Between Star Formation and Black Hole Accretion in Nearby Active Galaxies
• An elliptical accretion disk following the tidal disruption event AT 2020zso
• BASS XXIX: The near-infrared view of the BLR: the effects of obscuration in BLR characterisation
• BAT AGN Spectroscopic Survey--VIII. Type 1 AGN With Massive Absorbing Columns
• The Eddington ratio-dependent changing look events in NGC 2992
• A Catalog of Host Galaxies for WISE-Selected AGN: Connecting Host Properties with Nuclear Activity and Identifying Contaminants
• Modeling accretion disk emission with generalized temperature profile and its effect on AGN spectral energy distribution
• Thick turbulent gas disks with magnetocentrifugal winds in active galactic nuclei - Model infrared emission and optical polarization
• Oxygen abundances in the narrow line regions of Seyfert galaxies and the metallicity-luminosity relation
• A Comparison of Two Methods for Estimating Black Hole Spin in Active Galactic Nuclei
• LLAMA: Stellar populations in the nuclei of ultra hard X-ray selected AGN and matched inactive galaxies
• JWST ERS Program Q3D: The pitfalls of virial BH mass constraints shown in a z = 3 quasar with an ultramassive host
• LLAMA: Nuclear stellar properties of Swift BAT AGN and matched inactive galaxies
• Exploring the AGN-Merger Connection in Arp 245 I: Nuclear Star Formation and Gas Outflow in NGC 2992
• The nascent milliquasar VT J154843.06+220812.6: tidal disruption event or extreme accretion-state change?
• 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
• Photoionization Modelling of the Giant Broad-Line Region in NGC 3998
• Measurement of AGN dust extinction based on the near-infrared flux variability of WISE data
• Polarized radiative transfer modeling of warped and clumpy dusty tori
• SALT long-slit spectroscopy of HE 0435-4312: fast displacement in the Mg II emission line
• Efficient Analysis Routines for Single and Double Peaked Type 2 AGN Spectra
• Updated Picture of the Active Galactic Nuclei with Dusty/Dust-free Gas Structures and Effects of the Radiation Pressure
• A Peculiar Type~II QSO Identified via Broad-band Detection of Extreme Nebular Line Emission
• X-ray absorption and 9.7 um silicate feature as a probe of AGN torus structure
• Physical Models for the Clustering of Obscured and Unobscured Quasars
• Extinction and AGN over host galaxy contrast effects on the optical spectroscopic classification of AGN
• The Southern Hemisphere Narrow-Line Seyfert 1 Infrared Survey
• The CaFe Project: Optical FeII and Near-Infrared Ca II triplet emission in active galaxies. II. The driver(s) of the Ca II and Fe II and its potential use as a chemical clock
• A new panchromatic classification of unclassified Burst Alert Telescope active galactic nuclei
• X-ray properties of two complementary samples of intermediate Seyfert galaxies