Ultra high energy cosmic rays: implications of Auger data for source spectra and chemical composition

Abstract

We use a kinetic-equation approach to describe the propagation of ultra high energy cosmic ray protons and nuclei and calculate the expected spectra and mass composition at the Earth for different assumptions on the source injection spectra and chemical abundances. When compared with the spectrum, the elongation rate $X_{max}(E)$ and dispersion $\sigma (X_{max})$ as observed with the Pierre Auger Observatory, several important consequences can be drawn: a) the injection spectra of nuclei must be very hard, $\sim E^{-\gamma }$ with $\gamma \sim 1-1.6$; b) the maximum energy of nuclei of charge $Z$ in the sources must be $\sim 5Z\times 10^{18}$ eV, thereby not requiring acceleration to extremely high energies; c) the fit to the Auger spectrum can be obtained only at the price of adding an {\it ad hoc} light extragalactic component with a steep injection spectrum ($\sim E^{-2.7}$). In this sense, at the ankle ($E_A\approx 5\times 10^{18}$ eV) all the components are of extragalactic origin, thereby suggesting that the transition from Galactic to extragalactic cosmic rays occurs below the ankle. Interestingly, the additional light extragalactic component postulated above compares well, in terms of spectrum and normalization, with the one recently measured by KASCADE-Grande.

18 pages, 12 eps figures, accepted for publication in JCAP

References in corpus (11)

• The Origin of Galactic Cosmic Rays
• New facts about muon production in Extended Air Shower simulations
• A dip in the UHECR spectrum and the transition from galactic to extragalactic cosmic rays
• Ankle-like Feature in the Energy Spectrum of Light Elements of Cosmic Rays Observed with KASCADE-Grande
• Constraints on the origin of cosmic rays above $10^{18}$ eV from large scale anisotropy searches in data of the Pierre Auger Observatory
• The Pierre Auger Observatory I: The Cosmic Ray Energy Spectrum and Related Measurements
• CRPropa: A Numerical Tool for the Propagation of UHE Cosmic Rays, Gamma-rays and Neutrinos
• Signatures of the transition from galactic to extragalactic cosmic rays
• UHECR Composition Models
• Origin of very high and ultra high energy cosmic rays
• The origin of galactic cosmic rays

Cited by in corpus (96)

• Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory
• Multi-Messenger Astrophysics
• Features of the energy spectrum of cosmic rays above $2.5\times 10^{18}$ eV using the Pierre Auger Observatory
• Ultra-High-Energy Cosmic Rays
• Origin of the ankle in the ultra-high energy cosmic ray spectrum and of the extragalactic protons below it
• The Cosmic-Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE detector in monocular mode
• Cosmic-ray energy spectrum and composition up to the ankle - the case for a second Galactic component
• The energy spectrum of cosmic rays beyond the turn-down around $10^{17}$ eV as measured with the surface detector of the Pierre Auger Observatory
• A new view on Auger data and cosmogenic neutrinos in light of different nuclear disintegration and air-shower models
• A complete model of the CR spectrum and composition across the Galactic to Extragalactic transition
• On the cosmic ray spectrum from type II Supernovae expanding in their red giant presupernova wind
• Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers
• Lepton fluxes from atmospheric charm revisited
• Indications of Negative Evolution for the Sources of the Highest Energy Cosmic Rays
• Cosmogenic Neutrinos Challenge the Cosmic Ray Proton Dip Model
• "Espresso" Acceleration of Ultra-high-energy Cosmic Rays
• Effects of uncertainties in simulations of extragalactic UHECR propagation, using CRPropa and SimProp
• Ultrahigh-energy Cosmic-ray Nuclei from Black Hole Jets: Recycling Galactic Cosmic Rays through Shear Acceleration
• Super Heavy Dark Matter in light of BICEP2, Planck and Ultra High Energy Cosmic Rays Observations
• On the common origin of cosmic rays across the ankle and diffuse neutrinos at the highest energies from low-luminosity Gamma-Ray Bursts
• Acceleration of ultrahigh-energy cosmic rays in starburst superwinds
• Constraining the sources of ultra-high-energy cosmic rays across and above the ankle with the spectrum and composition data measured at the Pierre Auger Observatory
• Cosmic Ray Models
• The fate of ultrahigh energy nuclei in the immediate environment of young fast-rotating pulsars
• Cosmogenic neutrinos and ultra-high energy cosmic ray models
• Implications of Strong Intergalactic Magnetic Fields for Ultra-High-Energy Cosmic-Ray Astronomy
• The Cosmic-Ray Composition between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular Mode
• Nuclear Physics Meets the Sources of the Ultra-High Energy Cosmic Rays
• Cosmic Rays from the Ankle to the Cut-Off
• High energy cosmic ray self-confinement close to extragalactic sources
• Probing Cosmic-Ray Accelerated Light Dark Matter with IceCube
• Bottom-up Acceleration of Ultra-High-Energy Cosmic Rays in the Jets of Active Galactic Nuclei
• Diffusion of cosmic rays at EeV energies in inhomogeneous extragalactic magnetic fields
• Origin of very high and ultra high energy cosmic rays
• Limits on the Lorentz Invariance Violation from UHECR astrophysics
• Implications of gamma-ray observations on proton models of UHECR
• What can be learnt from UHECR anisotropies observations? Paper I : large-scale anisotropies and composition features
• Acceleration and propagation of ultra high energy cosmic rays
• Espresso and Stochastic Acceleration of Ultra-high-energy Cosmic Rays in Relativistic Jets
• On ultra high energy cosmic rays and their resultant gamma rays
• Extragalactic cosmic rays diffusing from two populations of sources
• Modeling the spectrum and composition of ultrahigh-energy cosmic rays with two populations of extragalactic sources
• White paper on EUSO-SPB2
• Diffuse flux of ultra-high energy photons from cosmic-ray interactions in the disk of the Galaxy and implications for the search for decaying super-heavy dark matter
• Binary Neutron Star Merger Remnants as Sources of Cosmic Rays Below the "Ankle"
• Origin of the light cosmic ray component below the ankle
• Energetics of ultrahigh-energy cosmic-ray nuclei
• Ultra-High-Energy Cosmic Rays Accelerated by Magnetically Dominated Turbulence
• Cosmic Rays around $10^{18}$eV: Implications of Contemporary Measurements on the Origin of the Ankle Feature
• Impact of the Magnetic Horizon on the Interpretation of the Pierre Auger Observatory Spectrum and Composition Data
• Energy Spectrum of Fast Second Order Fermi Accelerators as Sources of Ultra-High-Energy Cosmic Rays
• Cosmic rays: the spectrum and chemical composition from $10^{10}$ to $10^{20}$ eV
• PeV-EeV neutrinos from gamma-ray blazars due to ultrahigh-energy cosmic-ray propagation
• Selected Topics in Cosmic Ray Physics
• Determination of the Cosmic-Ray Chemical Composition: Open Issues and Prospects
• The shape of the extragalactic cosmic ray spectrum from Galaxy Clusters
• Ultra High Energy Cosmic Rays -- an Overview
• High-Energy Neutrino Emission from Espresso-Reaccelerated Ions in Jets of Active Galactic Nuclei
• Ultrahigh-energy neutrinos as a probe of espresso-shear acceleration in jets of Centaurus A
• The spectra and composition of Ultra High Energy Cosmic Rays and the measurement of the proton-air cross section
• Lower limit on the ultra-high-energy proton-to-helium ratio from the measurements of the tail of $X_{\max }$ distribution
• Atmospheric neutrinos and the knee of the Cosmic Ray spectrum
• Can we reconcile the TA excess and hotspot with Auger observations?
• Ultrahigh Energy Cosmic Rays: A Galactic Origin?
• Search for ultra high energy cosmic rays from radiogalaxy Virgo A
• Are Cosmic Rays still a valuable probe of Lorentz Invariance Violations in the Auger era?
• New test of Lorentz symmetry using ultrahigh-energy cosmic rays
• Nearby active galactic nuclei and starburst galaxies as sources of the measured UHECRs anisotropy signal
• Future prospects of testing Lorentz invariance with UHECRs
• Surprises from extragalactic propagation of UHECRs
• Case for Centaurus A as the main source of ultrahigh-energy cosmic rays
• Probing UHECR production in Centaurus A using secondary neutrinos and gamma-rays
• Inverse problem for extragalactic transport of ultra-high energy cosmic rays
• Extragalactic Propagation of Ultra-High Energy Cosmic Rays
• Effects of large-scale magnetic fields on the observed composition of ultra high-energy cosmic rays
• On the cosmic ray spectrum from type II Supernovae
• Ultra-High Energy Cosmic Rays: Recent Results and Future Plans of Auger
• Between the cosmic-ray `knee' and the `ankle': Contribution from star clusters
• Revisiting Propagation Delays of Ultra-High-Energy Cosmic Rays from Long-lived Sources
• Neutrinos at extreme energies
• Modeling Hadronic Interactions in Ultra-High-Energy Cosmic Rays within Astrophysical Environments: A Parametric Approach
• Astrophysical constraints on the simulation hypothesis for this Universe: why it is (nearly) impossible that we live in a simulation
• The Physics of UHECRs: Spectra, Composition and the Transition Galactic-Extragalactic
• On the efficiency of the evaluation of the primary cosmic ray composition using lateral distributions of air shower electromagnetic component
• Lateral distributions of electrons in air showers initiated by ultra-high energy gamma quanta taking into account LPM and geomagnetic field effects
• CRPropa - A Toolbox for Cosmic Ray Simulations
• Unveiling the nature of the unidentified gamma-ray sources 4FGL J1908.6+0915e, HESS J1907+089/HOTS J1907+091, and 3HWC J1907+085 in the sky region of the magnetar SGR 1900+14
• Ultra High Energy Cosmic Rays: Origin, Composition and Spectrum
• Astrophysical interpretation of Pierre Auger Observatory measurements of the UHECR energy spectrum and mass composition
• Ultra-high energy cosmic rays with UFA-15 source model in Bumblebee gravity theory
• Study of Galactic interactions and propagation properties of ultrahigh energy cosmic rays using the precision spectrum from the Pierre Auger Observatory
• Ultra high-energy cosmic rays from beyond the Greisen-Zatsepin-Kuz'min horizon
• Ultrahigh energy cosmic ray nuclei from remnants of dead quasars
• Ultra High Energy Cosmic Rays and the Highest Energies Universe
• UHECR primary identification using the lateral profile of muons in EAS
• Propagation of Ultra High Energy Cosmic Rays and the Production of Cosmogenic Neutrinos