The Jet-Disk Coupling of Seyfert Galaxies from a Complete Hard X-ray Sample

TL;DR

This study investigates the relationship between jet power and accretion disk luminosity in Seyfert galaxies, revealing how their coupling varies with radio loudness and accretion rate, and proposing a cycle of jet-disk activity.

Contribution

It provides a detailed analysis of jet-disk coupling indices across different Seyfert types and accretion rates, highlighting the dependence on radio loudness and proposing a radio-active cycle model.

Findings

Jet-disk coupling index varies from nearly unity in radio-loud to less than unity in radio-quiet Seyferts.

Linear jet-disk coupling occurs at intermediate to high accretion rates, decreasing at super Eddington rates.

Seyfert 1 galaxies show slightly steeper jet-disk correlations than Seyfert 2 galaxies.

Abstract

We analyze the jet-disk coupling for different subsamples from a complete hard X-ray Seyfert sample to study the coupling indices and their relation to accretion rate. The results are: (1) the power-law coupling index ranges from nearly unity (linear correlation) for radio-loud Seyferts to significantly less than unity for radio-quiet ones. This declining trend of coupling index also holds from larger sources to compact ones; (2) the Seyferts with intermediate to high accretion rate (Eddington ratio $\lambda\sim$ 0.001 to 0.3) show a linear jet-disk coupling, but it shallows from near to super Eddington ($\lambda\sim$ 0.3 to 10), and the former is more radio loud than the latter; (3) the Seyfert 1s are slightly steeper than the Seyfert 2s, in the jet-disk correlation. In the linear coupling regime, the ratio of jet efficiency to radiative efficiency ($\eta/\varepsilon$) is nearly invariant, but in low accretion or super accretion regime, $\eta/\varepsilon$ varies with $\lambda$ in our model. We note that a radio-active cycle of accretion-dominated active galactic nuclei would be: from a weaker jet-disk coupling in $\lambda<0.001$ for low luminosity Seyferts, to a linear coupling in $0.001<\lambda<0.3$ for radio-loud luminous Seyferts and powerful radio galaxies/quasars, and to a weaker coupling in $0.3<\lambda<10$ ones.