Isotropic Luminosity Indicators in a Complete AGN Sample

TL;DR

This study evaluates various luminosity indicators for active galactic nuclei (AGN) using a complete Seyfert galaxy sample, confirming the isotropic nature of radio luminosity and the reliability of [O IV] as an intrinsic luminosity tracer.

Contribution

It provides a comprehensive comparison of different AGN luminosity proxies, highlighting the isotropic properties of radio and [O IV] emissions and the anisotropic nature of [O III] and X-ray emissions.

Findings

[O IV] correlates well with hard X-ray emission.

Radio luminosity shows no difference between obscured and unobscured AGNs.

[O III] and X-ray luminosities are systematically lower in obscured Seyferts.

Abstract

The [O IV] 25.89 micron line has been shown to be an accurate indicator of active galactic nucleus (AGN) intrinsic luminosity in that it correlates well with hard (10-200 keV) X-ray emission. We present measurements of [O IV] for 89 Seyfert galaxies from the unbiased Revised Shapley-Ames (RSA) sample. The [O IV] luminosity distributions of obscured and unobscured Seyferts are indistinguishable, indicating that their intrinsic AGN luminosities are quite similar and that the RSA sample is well suited for tests of the unified model. In addition, we analyze several commonly used proxies for AGN luminosity, including [O III] 5007 A, 6 cm radio, and 2-10 keV X-ray emission. We find that the radio luminosity distributions of obscured and unobscured AGNs show no significant difference, indicating that radio luminosity is a useful isotropic luminosity indicator. However, the observed [O III] and 2-10 keV luminosities are systematically smaller for obscured Seyferts, indicating that they are not emitted isotropically.