Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio Loudness of AGNs: Host Galaxy Morphology and the Spin Paradigm   We investigate how the total radio luminosity of AGN-powered radio sources
depends on their accretion luminosity and the central black hole mass. We find
that AGNs form two distinct and well separated sequences on the radio-loudness
- Eddington-ratio plane. We argue that these sequences mark the real upper
bounds of radio-loudness of two distinct populations of AGNs: those hosted
respectively by elliptical and disk galaxies. Both sequences show the same
dependence of the radio-loudness on the Eddington ratio (an increase with
decreasing Eddington ratio), which suggests that another parameter in addition
to the accretion rate must play a role in determining the jet production
efficiency in active galactic nuclei, and that this parameter is related to
properties of the host galaxy. The revealed host-related radio dichotomy breaks
down at high accretion rates where the dominant fraction of luminous quasars
hosted by elliptical galaxies is radio quiet. We argue that the huge difference
between the radio-loudness reachable by AGNs in disc and elliptical galaxies
can be explained by the scenario according to which the spin of a black hole
determines the outflow's power, and central black holes can reach large spins
only in early type galaxies (following major mergers), and not (in a
statistical sense) in spiral galaxies.

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The categories of this paper are: alg-geom
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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con