Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: FR-0 jetted active galaxies: extending the zoo of candidate sites for
  UHECR acceleration   Fanaroff-Riley (FR) 0 radio galaxies form a low-luminosity extension to the
well-established ultra-high-energy cosmic-ray (UHECR) candidate accelerators
FR-1 and FR-2 galaxies. Their much higher number density -- up to a factor five
times more numerous than FR-1 with $z\leq 0.05$ -- makes them good candidate
sources for an isotropic contribution to the observed UHECR flux. Here, the
acceleration and survival of UHECR in prevailing conditions of the FR-0
environment are discussed.
  First, an average spectral energy distribution (SED) is compiled based on the
\textit{FR0CAT}. These photon fields, composed of a jet and a host galaxy
component, form a minimal target photon field for the UHECR, which will suffer
from electromagnetic pair production, photo-disintegration, photo-meson
production losses, and synchrotron radiation. The two most promising
acceleration scenarios based on Fermi-I order and gradual shear acceleration
are discussed as well as different escape scenarios.
  When an efficient acceleration mechanism precedes gradual shear acceleration,
e.g., Fermi-I or others, FR-0 galaxies are likely UHECR accelerators. Gradual
shear acceleration requires a jet Lorentz factor of $\Gamma>1.6$, to be faster
than the corresponding escape. In less optimistic models, a contribution to the
cosmic-ray flux between the knee and ankle is expected to be relatively
independent of the realized turbulence and acceleration.

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The categories of this paper are: q-alg
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The categories of this paper are: math-ph
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: physics
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The categories of this paper are: nucl-th