A possible mechanism for multiple changing look phenomenon in Active Galactic Nuclei

Abstract

Changing-look phenomenon observed now in a growing number of active galaxies challenges our understanding of the accretion process close to a black hole. We propose a simple explanation for the sources where multiple semi-periodic outbursts are observed, and the sources are operating at a few per cent of the Eddington limit. The outburst are caused by the radiation pressure instability operating in the narrow ring between the standard gas-dominated outer disk and the hot optically thin inner Advection-Dominated Accretion Flow. The corresponding limit cycle is responsible for periodic outbursts, and the timescales are much shorter than the standard viscous timescale due to the narrowness of the unstable radial zone. Our toy model gives quantitative predictions and works well for multiple outbursts like those observed in NGC 1566, NGC 4151, NGC 5548 and GSN 069, although the shapes of the outbursts are not yet well modeled, and further development of the model is necessary.

10 pages, 10 figures. Accepted for publication in A&A. arXiv admin note: text overlap with arXiv:1904.06767

References in corpus (25)

• The AGN Black Hole Mass Database
• Space Telescope and Optical Reverberation Mapping Project. II. Swift and HST Reverberation Mapping of the Accretion Disk of NGC 5548
• Testing thermal reprocessing in AGN accretion discs
• A Reverberation-Based Mass for the Central Black Hole in NGC 4151
• AGN Type-casting: Mrk 590 No Longer Fits the Role
• Space Telescope and Optical Reverberation Mapping Project. I. Ultraviolet Observations of the Seyfert 1 Galaxy NGC 5548 with the Cosmic Origins Spectrograph on Hubble Space Telescope
• Mid-infrared variability of changing-look AGN
• iPTF Discovery of the Rapid "Turn On" of a Luminous Quasar
• Active galactic nuclei at z ~ 1.5: I. Spectral energy distribution and accretion discs
• The Existence of Inner Cool Disks in the Low Hard State of Accreting Black Holes
• The First Spectroscopically Resolved Sub-parsec Orbit of a Supermassive Binary Black Hole
• Space Telescope and Optical Reverberation Mapping Project VI: reverberating Disk Models for NGC 5548
• Radiation spectra of warm and optically thick coronae in AGN
• Supermassive black holes with high accretion rates in active galactic nuclei. XI. Accretion disk reverberation mapping of Mrk 142
• New changing look case in NGC 1566
• Long-term variability of the optical spectra of NGC 4151: I. Light curves and flux correlations
• Reverberation Mapping of the Broad-line Region in NGC 5548: Evidence for Radiation Pressure?
• Long-term optical spectral monitoring of a changing-look AGN NGC 3516 I: Continuum and broad-line flux variability
• Polarization of changing-look quasars
• Variability of Active Galactic Nuclei from the Optical to X-ray Regions
• MUSE observations of a changing-look AGN I: The re-appearance of the broad emission lines
• The universal "heartbeat" oscillations in black hole systems accross the mass-scale
• Accreting corona model of the X-ray variability in soft state X-ray binaries and active galactic nuclei
• The 'Big Dipper': The nature of the extreme variability of the AGN SDSS J2232-0806
• A systematic study of the advection-dominated accretion flow for the origin of the X-ray emission in weakly magnetized low-level accreting neutron star