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 decline trend of coupling index also holds from larger sources to compact ones; (2) the Seyferts with intermediate to high accretion rate (Eddington ratio λ ∼ 0.001 to 0.3) show a linear jet-disk coupling, but it shallows from near to super Eddington ( λ ∼ 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 ( η / ε ) is nearly invariant, but in low accretion or super accretion regime, η / ε varies with λ 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 λ < 0 . 001 for low luminosity Seyferts, to a linear coupling in 0 . 001 < λ < 0 . 3 for radio-loud luminous Seyferts and powerful radio galaxies/quasars, and to a weaker coupling in 0 . 3 < λ < 10 ones.
Highlights
Active galactic nuclei (AGNs) are the most powerful sources in the Universe and believed to be powered by their central massive black hole accretion
Of AGN lifetime) in the middle regime of accretion rate with an efficient jet-disk coupling, especially for luminous Seyfert galaxies in this paper and for FRII quasars in [14]. In this idea we do not consider local low luminosity AGNs (LLAGNs) that are about 50% radio loud [18,19], for that the fraction will be much smaller for a distant universe due to radio undetectablity of the local LLAGNs) and their jet might not be accretion dominated but black hole (BH)-spin dominated [20]. Another fundamental factor seems to be changes in the spectral energy distribution (SED), which is driven by changes in the type of accretion disk (RIAF, standard disk, superluminous disk) for different regimes of accretion rates [2,37], that may partly be related to the function of ratio η/ε on accretion rate and BH mass, and so the coupling of mechanical vs. radiative power, e.g., in Equation (2)
The results are: (i) the power-law coupling index ranges from nearly unity for radio loud Seyferts to significantly less than unity for radio quiet ones
Summary
Active galactic nuclei (AGNs) are the most powerful sources in the Universe and believed to be powered by their central massive black hole accretion. We can see that the jet-disk coupling is relative to the η/ε in Equation (1), which may be otherwise not constancy for different type of sources which being at different accretion rates [4] We absorb this unknown factor η/ε in Equation (1) into the power-law index μ in the form of 1+ q. We can fit the relation of jet power and disk luminosity with μ and derive the q, in order to study the jet-disk coupling for different subsamples These subsamples should come from a well-defined complete sample. We reanalyze the complete hard-X-ray Seyfert sample by Panessa et al [8] in more detail, in order to investigate the jet-disk coupling for different subsamples. In order to avoid strong Doppler boosting effect ( the luminosities measured are far away from their intrinsic values), sources like blazars are not included in this sample
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