AGN Broad Line Region variability in the context of Eigenvector 1: case of NGC 5548

Abstract

Many active galactic nuclei (AGN) show strong variability of the optical continuum. Since the line flux, profile shapes and intensity ratios are changing, we analyze the variability patterns and possible periodicity of Type 1 AGN NGC 5548, using the Eigenvector 1 (EV1) diagram in different variability states, taking advantage of very long term monitoring campaign data. The preliminary results suggest that NGC 5548 - a highly variable object that over several decades has shown large amplitude continuum fluctuations and flaring behavior - remains Pop B. This means that the range in Eddington ratio, even when the source is in a bright state, remains consistent with the value of the low accreting Pop B. We inspected EV 1 parameters of a single object though long term monitoring, assuming an inclination and black hole mass to be constant during the observational time. Our results imply that the main driver for the variations along the EV 1 diagram could be dimensionless accretion rate. If so, then it appears that the source never crossed the boundary for structural changes, indicatively placed at $L/L_{Edd}\sim$ 0.2.

arXiv comment14 pages, 7 figures, accepted for publication in Frontiers in Astronomy and Space Science

References in corpus (17)

• ULySS: A Full Spectrum Fitting Package
• The diversity of quasars unified by accretion and orientation
• What the Optical Recombination Lines Can Tell Us About the Broad Line Regions of Active Galactic Nuclei
• Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
• Searching for the Physical Drivers of the Eigenvector 1 Correlation Space
• The effect of radiation pressure on emission line profiles and black hole mass determination in active galactic nuclei
• Detailed Characterization of H_beta emission line profile in low z SDSS quasars
• Space Telescope and Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign and Emission-Line Analysis for NGC 5548
• Contribution of the Disk Emission to the Broad Emission Lines in AGNs: Two-component model
• VLT/ISAAC Spectra of the Hbeta Region in Intermediate-Redshift Quasars III. Hbeta Broad Line Profile Analysis and Inferences about BLR Structure
• Evidence for periodicity in 43 year-long monitoring of NGC 5548
• VLT/ISAAC Spectra of the H-beta Region in Intermediate-Redshift Quasars II. Black Hole Mass and Eddington Ratio
• The Demise of the Classical BLR in the Luminous Quasar PG1416-129
• Contribution of a Disk Component to Single Peaked Broad Lines of Active Galactic Nuclei
• The phylogeny of quasars and the ontogeny of their central black holes
• Complex Broad Emission Line Profiles of AGN - Geometry of the Broad Line Region
• Efficiency tests for estimating the gas and stellar population parameters in Type 2 objects

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