How does the Polar Dust affect the Correlation between Dust Covering Factor and Eddington Ratio in Type 1 Quasars Selected from the Sloan Digital Sky Survey Data Release 16?

TL;DR

This study investigates how polar dust emission influences the relationship between dust covering factor and key properties of type 1 quasars, revealing that polar dust strengthens the anti-correlations and plays a role in AGN obscuration regulation.

Contribution

It introduces a method to account for polar dust emission in CF estimation and demonstrates its impact on correlations with AGN properties, advancing understanding of dust's role in AGN physics.

Findings

Polar dust emission strengthens anti-correlations between CF and AGN properties.

Inclusion of polar dust indicates its role in regulating AGN obscuration.

Strong anti-correlations confirmed for CF with $L_{bol}$, $M_{BH}$, and $ m Edd$ ratio.

Abstract

We revisit the dependence of covering factor (CF) of dust torus on physical properties of active galactic nuclei (AGNs) by taking into account an AGN polar dust emission. The CF is converted from a ratio of infrared (IR) luminosity contributed from AGN dust torus ($L_{\rm IR}^{\rm torus}$) and AGN bolometric luminosity ($L_{\rm bol}$), by assuming a non-linear relation between luminosity ratio and intrinsic CF. We select 37,181 type 1 quasars at $z < 0.7$ from the Sloan Digital Sky Survey Data Release 16 quasar catalog. Their $L_{\rm bol}$, black hole mass ($M_{\rm BH}$), and Eddington ratio ($\lambda_{\rm Edd}$) are derived by spectral fitting with QSFit. We conduct spectral energy distribution decomposition by using X-CIGALE with clumpy torus and polar dust model to estimate $L_{\rm IR}^{\rm torus}$ without being affected by the contribution of stellar and AGN polar dust to IR emission. For 5720 quasars whose physical quantities are securely determined, we perform a correlation analysis on CF and (i) $L_{\rm bol}$, (ii) $M_{\rm BH}$, and (iii) $\lambda_{\rm Edd}$. As a result, anti-correlations for CF-$L_{\rm bol}$, CF-$M_{\rm BH}$, and CF-$\lambda_{\rm Edd}$ are confirmed. We find that incorporating the AGN polar dust emission makes those anti-correlations stronger which are compared to those without considering it. This indicates that polar dust wind provably driven by AGN radiative pressure is one of the key components to regulate obscuring material of AGNs.