Polarization microlensing in the quadruply imaged broad absorption line quasar H1413+117

TL;DR

This study uses spectropolarimetric observations of a gravitationally lensed quasar to investigate the polarization differences caused by microlensing, revealing insights into the structure of the quasar's scattering regions.

Contribution

First spectropolarimetric analysis of all four images of H1413+117, demonstrating microlensing effects on polarization and proposing a model for the scattering regions.

Findings

Microlensing affects polarization in different images.

Continuum scattered from two spatially separated regions.

Compact equatorial and extended polar scattering regions inferred.

Abstract

We have obtained spectropolarimetric observations of the four images of the gravitationally lensed broad absorption line quasar H1413+117. The polarization of the microlensed image D is significantly different both in the continuum and in the broad lines from the polarization of image A which is essentially unaffected by microlensing. The observations suggest that the continuum is scattered off two regions spatially separated and producing roughly perpendicular polarizations. These results are compatible with a model in which the microlensed polarized continuum comes from a compact region located in the equatorial plane close to the accretion disk and the non-microlensed continuum from an extended region located along the polar axis.