Title: | FR-0 jetted active galaxies : extending the zoo of candidate sites for UHECR acceleration |
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Authors: | Merten, Lukas (Author) Boughelilba, Margot (Author) Reimer, Anita (Author) Da Vela, Paolo (Author) Vorobiov, Serguei (Author) Tavecchio, Fabrizio (Author) Bonnoli, Giacomo (Author) Lundquist, Jon Paul (Author) Righi, Chiara (Author) |
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Files: | This document has no files. This document may have a phisical copy in the library of the organization, check the status via COBISS.  |
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Language: | English |
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Work type: | Unknown () |
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Tipology: | 1.08 - Published Scientific Conference Contribution |
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Organization: | UNG - University of Nova Gorica |
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Abstract: | 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 ≤ 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 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 orothers, 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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Keywords: | jetted active galaxies, FR-0 radiogalaxies, ultra-high energy cosmic rays, cosmic ray acceleration, cosmic ray energy losses |
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Year of publishing: | 2021 |
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Number of pages: | str. 1-8 |
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COBISS_ID: | 73062147  |
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UDC: | 539.1 |
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ISSN on article: | 1824-8039 |
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URN: | URN:SI:UNG:REP:QHH51HOF |
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Views: | 975 |
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Downloads: | 0 |
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