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.

6 pages, 5 figures. Accepted for publication in A&A

References in corpus (11)

• A Catalog of Quasar Properties from SDSS DR7
• The Discovery of the First "Changing Look" Quasar: New Insights into the Physics & Phenomenology of AGN
• Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
• A compendium of AGN inclinations with corresponding UV/optical continuum polarization measurements
• Modeling optical and UV polarization of AGNs III. From uniform-density to clumpy regions
• 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
• 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 (6)

• Polarization of changing-look quasars
• The Eddington ratio-dependent changing look events in NGC 2992
• Investigating Changing-Look Active Galactic Nuclei with Long-term Optical and X-Ray Observations
• Spectropolarimetry of the changing-look active galactic nucleus Mrk 1018
• The Awakening Beast in the Seyfert 1 Galaxy KUG 1141+371 I
• Optical polarization of stellar-fed active and quiescent supermassive black holes