A Novel Test of Quasar Orientation

TL;DR

This paper proposes a new spectroscopic method to determine the orientation of quasars, potentially identifying edge-on quasars without relying on radio or X-ray data, aiding understanding of quasar properties.

Contribution

It introduces a novel spectroscopic orientation indicator for quasars that could be applied to individual objects without radio or X-ray data.

Findings

Proposed a hypothesis for quasar orientation determination.

Identified a potential spectral feature (CIV 1549A) as an orientation indicator.

Suggested further X-ray data needed for validation.

Abstract

The orientation of the disk of material accreting onto supermassive black holes that power quasars is one of most important quantities that are needed to understand quasars -- both individually and in the ensemble average. We present a hypothesis for determining comparatively edge-on orientation in a subset of quasars (both radio loud and radio quiet). If confirmed, this orientation indicator could be applicable to individual quasars without reference to radio or X-ray data and could identify some 10-20% of quasars as being more edge-on than average, based only on moderate resolution and signal-to-noise spectroscopy covering the CIV 1549A emission feature. We present a test of said hypothesis using X-ray observations and identify additional data that are needed to confirm this hypothesis and calibrate the metric.