Quasar Host Orientation and Polarization: Insights into the Type 1/Type 2 Dichotomy

TL;DR

This study explores the relationship between quasar polarization and host galaxy orientation, revealing significant correlations that vary by quasar type and redshift, thus providing insights into the unification model of active galactic nuclei.

Contribution

It introduces high-resolution HST measurements of host galaxy orientations and analyzes their correlation with polarization angles across different quasar types and redshifts.

Findings

Significant correlation between polarization angle and host galaxy orientation.

Differences in correlation patterns between Type 1 and Type 2 quasars.

Dependence of correlation on the redshift of the sources.

Abstract

We investigate correlations between the optical linear polarization position angle and the orientation of the host galaxy/extended emission of Type 1 and Type 2 Radio-Loud (RL) and Radio-Quiet (RQ) quasars. We have used high resolution Hubble Space Telescope (HST) data and deconvolution process to obtain a good determination of the host galaxy orientation. With these new measurements and a compilation of data from the literature, we find a significant correlation between the polarization position angle and the position angle of the major axis of the host galaxy/extended emission. The correlation appears different for Type 1 and Type 2 objects and depends on the redshift of the source. Interpretations in the framework of the unification model are discussed.