Espresso and Stochastic Acceleration of Ultra-high-energy Cosmic Rays in Relativistic Jets
arXiv:2105.05262 · doi:10.3847/1538-4357/ac1da8
Abstract
In the espresso scenario, ultra-high-energy (UHE) cosmic rays (CRs) are produced via a one-shot reacceleration of galactic-like CRs in the relativistic jets of active galactic nuclei, independently of the scattering rate dictated by magnetic fluctuations. In Mbarek & Caprioli (2019), we traced test-particle CRs in high-resolution magnetohyrodynamic (MHD) jet simulations and found that the associated spectral slope, chemical composition, and anisotropy are consistent with UHECR phenomenology. In this work, we extend such an analysis by including sub-grid pitch-angle scattering to model small-scale magnetic turbulence that cannot be resolved by MHD simulations. We find that a large scattering rate unlocks stochastic acceleration and fosters the energization of lower-energy CRs, which eventually leads to harder UHECR spectra. Yet, the particles that achieve the highest energies (up to the Hillas limit) are invariably produced by espresso acceleration and their spectrum is independent of the assumed sub-grid scattering rate.
arXiv comment12 pages, 9 figures; Accepted to ApJ
References in corpus (38)
- PLUTO: a Numerical Code for Computational Astrophysics
- COSMOLOGICAL GAMMA RAY BURSTS AND THE HIGHEST ENERGY COSMIC RAYS
- On the acceleration of Ultra High Energy Cosmic Rays in Gamma Ray Bursts
- The PLUTO Code for Adaptive Mesh Computations in Astrophysical Fluid Dynamics
- The Astrophysics of Ultrahigh Energy Cosmic Rays
- Depth of Maximum of Air-Shower Profiles at the Pierre Auger Observatory: Measurements at Energies above 10^17.8 eV
- X-ray Emission from Extragalactic Jets
- Blazars as Ultra-High-Energy Cosmic-Ray Sources: Implications for TeV Gamma-Ray Observations
- TeV BL Lac objects at the dawn of the Fermi era
- Three-dimensional Relativistic MHD Simulations of Active Galactic Nuclei Jets: Magnetic Kink Instability and Fanaroff-Riley Dichotomy
- Ultra high energy cosmic rays: implications of Auger data for source spectra and chemical composition
- Report on Tests and Measurements of Hadronic Interaction Properties with Air Showers
- Linking High-Energy Cosmic Particles by Black-Hole Jets Embedded in Large-Scale Structures
- A survey of extended radio jets in AGN with Chandra and HST: First Results
- Formation of dynamical structures in relativistic jets: the FRI case
- Newly-born pulsars as sources of ultrahigh energy cosmic rays
- Chandra Discovery of a 300 kpc X-ray Jet in the GPS Quasar PKS1127-145
- A new view on Auger data and cosmogenic neutrinos in light of different nuclear disintegration and air-shower models
- FR0CAT: a FIRST catalog of FR0 radio galaxies
- The maximum momentum of particles accelerated at cosmic ray modified shocks
- Stochastic particle acceleration in the lobes of giant radio galaxies
- "Espresso" Acceleration of Ultra-high-energy Cosmic Rays
- Ultra-high energy cosmic rays from shocks in the lobes of powerful radio galaxies
- Bayesian inference of jet bulk-flow speeds in FRII radio sources
- Ultrahigh-energy Cosmic-ray Nuclei from Black Hole Jets: Recycling Galactic Cosmic Rays through Shear Acceleration
- High-resolution VLA observations of FR0 radio galaxies: properties and nature of compact radio sources
- On possible `cosmic ray cocoons' of relativistic jets
- On the jet speeds of classical double radio sources
- Particle Acceleration in Mildly Relativistic Shearing Flows: the Interplay of Systematic and Stochastic Effects, and the Origin of the Extended High-energy Emission in AGN Jets
- UHECR Composition Models
- X-ray study of a sample of FR0 radio galaxies: unveiling the nature of the central engine
- Jets from Sub-Parsec to Kiloparsec Scales: A Physical Connection
- Bottom-up Acceleration of Ultra-High-Energy Cosmic Rays in the Jets of Active Galactic Nuclei
- FR0 radio galaxies and their place in the radio morphology classification
- Constraining the shear acceleration model for the X-ray emission of large-scale extragalactic jets
- Report of the Working Group on the Composition of Ultra High Energy Cosmic Rays
- Scrutinizing FR 0 Radio Galaxies as Ultra-High-Energy Cosmic Ray Source Candidates
- Stochastic Acceleration of Cosmic Rays in the Central Molecular Zone of the Galaxy