Case for Centaurus A as the main source of ultrahigh-energy cosmic rays

Abstract

We discuss the possibility that a dominant fraction of the cosmic rays above the ankle is due to a single nearby source, considering in particular the radio galaxy Centaurus A. We focus on the properties of the source spectrum and composition required to reproduce the observations, showing that the nuclei are strongly suppressed for E>10Z EeV, either by a rigidity dependent source cutoff or by the photodisintegration interactions with the CMB at the giant dipole resonance. The very mild attenuation effects at lower energies imply that the secondary nuclei from this source only provide a small contribution. Given the moderate anisotropies observed, the deflections in extragalactic and Galactic magnetic fields should play a crucial role in determining the cosmic ray arrival direction distribution. The diffusion in extragalactic fields as well as the finite source lifetime also significantly affect the shape of the observed spectrum. The cosmic ray flux at tens of EeV is dominated by the CNO component, and we show that it is actually better reproduced by a mixture of C and O nuclei rather than by the usual assumption of a N component effectively describing this mass group. The Si and Fe group components become dominant above 70 EeV, in the energy range in which a strong spectral suppression is present. If the localised flux excess appearing above 40 EeV around the Centaurus A direction is attributed to the CNO component, the He nuclei from the source in the energy range from 10 to 20 EeV could lead to a similar anisotropy unless its contribution is suppressed. The cosmic ray flux at a few EeV should mostly result from a more isotropic light component associated to a population of extragalactic sources. The inclusion of the subdominant contribution of heavy nuclei from the Galactic component helps to reproduce the observations around 1 EeV.

matches published version

References in corpus (52)

• On the normalisation of the cosmic star formation history
• Clusters of galaxies : observational properties of the diffuse radio emission
• A New Model of the Galactic Magnetic Field
• Semi-analytic modeling of the EBL and consequences for extragalactic gamma-ray spectra
• Observation of a Large-scale Anisotropy in the Arrival Directions of Cosmic Rays above $8\times 10^{18}$ eV
• Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory
• Centaurus A - NGC 5128
• Searches for Anisotropies in the Arrival Directions of the Highest Energy Cosmic Rays Detected by the Pierre Auger Observatory
• Giant AGN Flares and Cosmic Ray Bursts
• Origin of the ankle in the ultra-high energy cosmic ray spectrum and of the extragalactic protons below it
• Ultra high energy cosmic rays: implications of Auger data for source spectra and chemical composition
• Large-scale cosmic-ray anisotropies above 4 EeV measured by the Pierre Auger Observatory
• Extra-galactic magnetic fields and the second knee in the cosmic-ray spectrum
• Anisotropy vs chemical composition at ultra-high energies
• 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
• Diffusive propagation of UHECR and the propagation theorem
• The toes of the ultra high energy cosmic ray spectrum
• A complete model of the CR spectrum and composition across the Galactic to Extragalactic transition
• Lensing of ultra-high energy cosmic rays in turbulent magnetic fields
• Tidally disrupted stars as a possible origin of both cosmic rays and neutrinos at the highest energies
• An extremely energetic cosmic ray observed by a surface detector array
• Anisotropies of ultra-high energy cosmic rays diffusing from extragalactic sources
• The need for a local source of UHE CR nuclei
• GZK Violation - a Tempest in a (Magnetic) Teapot?
• Signatures of the Origin of High-Energy Cosmic Rays in Cosmological Gamma-Ray Bursts
• A Magnetized Local Supercluster and the Origin of the Highest Energy Cosmic Rays
• 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
• High-energy cosmic ray nuclei from tidal disruption events: Origin, survival, and implications
• Fornax A, Centaurus A and other radio galaxies as sources of ultra-high energy cosmic rays
• Magnetic diffusion effects on the Ultra-High Energy Cosmic Ray spectrum and composition
• Progress in high-energy cosmic ray physics
• Signatures of galactic magnetic lensing upon ultra high energy cosmic rays
• The Imprint of Large Scale Structure on the Ultra-High-Energy Cosmic Ray Sky
• Diffusion of Cosmic Rays in the Expanding Universe. II. Energy Spectra of Ultra-High Energy Cosmic Rays
• Ultrahigh energy cosmic rays from a nearby extragalactic source in the diffusive regime
• Ultra-high-energy-cosmic-ray hot spots from tidal disruption events
• Ultrahigh-energy cosmic rays from tidally-ignited white dwarfs
• Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory
• Magnetic Deflections of Ultra-High Energy Cosmic Rays from Centaurus A
• Evidence of Intermediate-Scale Energy Spectrum Anisotropy of Cosmic Rays E$\ge$10${}^{19.2}$ eV with the Telescope Array Surface Detector
• What can be learnt from UHECR anisotropies observations? Paper I : large-scale anisotropies and composition features
• Revisiting the distance to the nearest UHECR source: Effects of extra-galactic magnetic fields
• Curious case of the maximum rigidity distribution of cosmic-ray accelerators
• Extragalactic cosmic rays diffusing from two populations of sources
• Anisotropies of ultrahigh-energy cosmic rays in a scenario with nearby sources
• Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory
• Angular distribution of cosmic rays from an individual source in a turbulent magnetic field
• Cosmic ray anisotropies from transient extragalactic sources
• Impact of the Magnetic Horizon on the Interpretation of the Pierre Auger Observatory Spectrum and Composition Data
• A scenario for the Galactic cosmic rays between the knee and the second-knee
• The shape of the extragalactic cosmic ray spectrum from Galaxy Clusters
• Impact of the finite life-time of UHECR sources

Cited by in corpus (4)

• Ultrahigh-energy neutrinos as a probe of espresso-shear acceleration in jets of Centaurus A
• Impact of the EPOS.LHC-R hadronic interaction model on the Centaurus A ultrahigh-energy cosmic-ray scenario
• Recent advances on multimessenger astrophysics: Centaurus A, GW 170817, and KM3-230213A
• Modelling Cosmic Rays Flux with Pierre Auger and Telescope Array Data in $\mathbf{f}(\mathbf{R})$ and $\mathbf{f}(\mathbf{Q})$ Theories of Gravity