Quasar Viscosity Crisis

Abstract

Recent observations of extreme variability in Active Galactic Nuclei have pushed standard viscous accretion disc models over an edge. "Extreme reprocessing" where an erratically variable central quasi-point source is entirely responsible for heating an otherwise cold and passive low-viscosity disc, may be the best route forward.

For consistency with Nature policy, the version posted here is the text as submitted to Nature Astronomy in November 2017. The final version is available at the DOI below, and differs slightly in wording. The final version can be posted in six months

References in corpus (2)

• Space Telescope and Optical Reverberation Mapping Project. II. Swift and HST Reverberation Mapping of the Accretion Disk of NGC 5548
• Measuring Quasar Variability with Pan-STARRS1 and SDSS

Cited by in corpus (70)

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• Disc tearing: implications for black hole accretion and AGN variability
• Improving Damped Random Walk parameters for SDSS Stripe 82 Quasars with Pan-STARRS1
• Corona-Heated Accretion-disk Reprocessing (CHAR): A Physical Model to Decipher the Melody of AGN UV/optical Twinkling
• The remarkable X-ray variability of IRAS 13224-3809 I: The variability process
• The 450 days X-ray monitoring of the changing-look AGN 1ES 1927+654
• Initial results from a systematic search for changing-look active galactic nuclei selected via mid-infrared variability
• Opacity Driven Convection and Variability in Accretion Disks around Supermassive Black Holes
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• The Sloan Digital Sky Survey Reverberation Mapping Project: Accretion and Broad Emission Line Physics from a Hypervariable Quasar
• Feedback-Dominated Accretion Flows
• Changing-look active galactic nuclei: close binaries of supermassive black holes in action
• The first high-redshift changing-look quasars
• A deep X-ray view of the bare AGN Ark120. V. Spin determination from disc-Comptonisation efficiency method
• Radiation Transport Two-Temperature GRMHD Simulations of Warped Accretion Disks
• Nozzle Shocks, Disk Tearing and Streamers Drive Rapid Accretion in 3D GRMHD Simulations of Warped Thin Disks
• Supermassive black holes with high accretion rates in active galactic nuclei: X. Optical variability characteristics
• The Landscape of Galaxies Harboring Changing-Look Active Galactic Nuclei in the Local Universe
• Extreme Variability and Episodic Lifetime of Quasars
• A magnetic accretion disk-outflow model for changing look active galactic nuclei
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• The Eddington ratio-dependent changing look events in NGC 2992
• High-redshift Extreme Variability Quasars from Sloan Digital Sky Survey Multi-Epoch Spectroscopy
• The SOUX AGN sample: Optical/UV/X-ray SEDs and the nature of the disc
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• Spectral Variability of a Sample of Extreme Variability Quasars and Implications for the MgII Broad-line Region
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• AT 2021loi: A Bowen Fluorescence Flare with a Rebrightening Episode, Occurring in a Previously-Known AGN
• Optical and X-ray discovery of the changing-look AGN IRAS23226-3843 showing extremely broad and double-peaked Balmer profiles
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• Modeling Quasar UV/Optical Variability with the Corona-heated Accretion-disk Reprocessing (CHAR) Model
• Modelling Continuum Reverberation in AGN: A Spectral-Timing Analysis of the UV Variability Through X-ray Reverberation in Fairall 9
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• Discovery of late-time X-ray flare and anomalous emission line enhancement after the nuclear optical outburst in a narrow-line Seyfert 1 Galaxy
• Active galactic nuclei ghosts: A systematic search for faded nuclei
• Flares in the changing look AGN Mrk 590. I: The UV response to X-ray outbursts suggests a more complex reprocessing geometry than a standard disk
• Local Active Galactic Nuclei with Large Broad-Hα Variability Reside in Red Galaxies
• The Paschen Jump as a Diagnostic of the Diffuse Nebular Continuum Emission in Active Galactic Nuclei
• The nascent milliquasar VT J154843.06+220812.6: tidal disruption event or extreme accretion-state change?
• A Mid-infrared Flare in the Active Galaxy MCG-02-04-026: Dust Echo of a Nuclear Transient Event
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• Still alive and kicking: A significant outburst in changing-look AGN Mrk 1018
• Searching for Super-Eddington Quasars using a Photon Trapping Accretion Disc Model
• The interaction of the active nucleus with the host galaxy interstellar medium
• B3\,0749+460A: A New "Changing-Look" Active Galactic Nucleus Associated with X-ray Spectral Slope Variations
• Suspended and restored activities of A Nearby Super Massive Black Hole
• The Average Soft X-ray Spectra of eROSITA Active Galactic Nuclei
• Observational nonstationarity of AGN variability: The only way to go is down!
• SkyMapper colours of Seyfert galaxies and Changing-Look AGN
• Active galactic nuclei catalog from the AKARI NEP Wide field
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• Flares in the Changing Look AGN Mrk 590. II: Deep X-ray observations reveal a Comptonizing inner accretion flow
• A redshifted excess in the broad emission lines after the flare of the $\gamma$-ray narrow-line Seyfert 1 PKS 2004-447
• Untangling the Complex Nature of AGN Variability with Fairall 9
• Reprocessing Models for the Optical Light Curves of Hypervariable Quasars from the Sloan Digital Sky Survey Reverberation Mapping Project
• Optical Variability as a Probe of Hidden Nuclear Activity in Type 2 AGNs
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• X-ray Quasi-Periodic Oscillations in Active Galactic Nuclei and Their Implications for the Changing Look Phenomenon