Unveiling the physics behind the spectral variations of "changing-look" quasars with optical polarimetry

Abstract

A handful of active galactic nuclei (AGN) have shown strong spectral variations in the optical band between epochs that are years apart. The appearance or disappearance of broad emission lines in their spectra completely changes their classification. Since their nucleus orientation cannot change in such short timescales another physical interpretation has to be found. Several scenarios are competing to explain their changing-look nature and, for the first time, we conduct polarized radiative transfer Monte Carlo simulations for all the models. We demonstrate that all interpretations have distinctive features in both total optical flux and continuum polarization such as proposed by Hutsemékers and collaborators. Distinguishing between the different scenarios is thus straightforward. We apply our results on the changing-look quasar J1011+5442 and confirm the conclusions found by Hutsemékers and collaborators: in this specific case, the disappearance of the broad emission lines is due to a change in accretion rate.

arXiv comment6 pages, 5 figures. Accepted for publication in A&A

References in corpus (28)

• A Catalog of Quasar Properties from SDSS DR7
• The AGN Obscuring Torus -- End of the "Doughnut" Paradigm?
• Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• A Systematic Search for Changing-Look Quasars in SDSS
• Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
• The luminosity dependence of the Type 1 AGN fraction
• Changing look: from Compton-thick to Compton-thin, or the re-birth of fossil AGN
• On the Disappearance of the Broad-Line Region in Low-Luminosity Agns
• What broad emission lines tell us about how active galactic nuclei work
• Evolution of Broad-line Emission from Active Galactic Nuclei
• Modeling optical and UV polarization of AGNs I. Imprints of individual scattering regions
• A Spectropolarimetric Atlas of Seyfert 1 Galaxies
• IC 751: a new changing-look AGN discovered by NuSTAR
• A compendium of AGN inclinations with corresponding UV/optical continuum polarization measurements
• Modeling optical and UV polarization of AGNs II. Polarization imaging and complex reprocessing
• Are there reliable methods to estimate the nuclear orientation of Seyfert galaxies?
• Modeling optical and UV polarization of AGNs III. From uniform-density to clumpy regions
• Does the obscured AGN fraction really depend on luminosity?
• Polarization of X-ray emission from the Sgr B2 cloud
• The dust origin of the Broad Line Region and the model consequences for AGN unification scheme
• Polarization of the changing-look quasar J1011+5442
• A robust derivation of the tight relationship of radio core dominance to inclination angle in high redshift 3CRR sources
• Discovery of Polarization Reverberation in NGC 4151
• An optical spectroscopic survey of the 3CR sample of radio galaxies with z<0.3. V. Implications for the unified model for FRIIs
• Prospects of 3D mapping of the Galactic Centre clouds with X-ray polarimetry
• Reflection nebulae in the Galactic Center: the case for soft X-ray imaging polarimetry
• Computation of the transmitted and polarized scattered fluxes by the exoplanet HD 189733b in X-rays

Cited by in corpus (15)

• Discovery of 21 New Changing-look AGNs in Northern Sky
• Understanding extreme quasar optical variability with CRTS: II. Changing-state quasars
• Polarization of changing-look quasars
• A model for AGN variability on multiple timescales
• AGN Black hole mass estimates using polarization in broad emission Lines
• The Eddington ratio-dependent changing look events in NGC 2992
• A forward modelling approach to AGN variability -- Method description and early applications
• Investigating Changing-Look Active Galactic Nuclei with Long-term Optical and X-Ray Observations
• A complete disclosure of the hidden type-1 AGN in NGC 1068 thanks to 52 years of broadband polarimetric observation
• Spectropolarimetry of the changing-look active galactic nucleus Mrk 1018
• Tracking the state transitions in changing-look active galactic nuclei through their polarized-light echoes
• The Awakening Beast in the Seyfert 1 Galaxy KUG 1141+371 I
• Modelling quantum aspects of disruption of a white dwarf star by a black hole
• Optical polarization of stellar-fed active and quiescent supermassive black holes
• A changing-look AGN to be probed by X-ray polarimetry