Centaurus A as the Source of ultra-high energy cosmic rays?

Abstract

We present numerical simulations for energy spectra and angular distributions of nucleons above 10^{19} eV injected by the radio-galaxy Centaurus A at a distance 3.4 Mpc and propagating in extra-galactic magnetic fields in the sub-micro Gauss range. We show that field strengths B~0.3 micro Gauss, as proposed by Farrar and Piran, cannot provide sufficient angular deflection to explain the observational data. A magnetic field of intensity ~1 micro Gauss could reproduce the observed large-scale isotropy and could marginally explain the observed energy spectrum. However, it would not readily account for the E=320 plusminus 93 EeV Fly's Eye event that was detected at an angle 136 degrees away from Cen-A. Such a strong magnetic field also saturates observational upper limits from Faraday rotation observations and X-ray bremsstrahlung emission from the ambient gas (assuming equipartition of energy). This scenario may already be tested by improving magnetic field limits with existing instruments. We also show that high energy cosmic ray experiments now under construction will be able to detect the level of anisotropy predicted by this scenario. We conclude that for magnetic fields B~0.1-0.5 micro Gauss, considered as more reasonable for the local Supercluster environment, in all likelihood at least a few sources within ~10 Mpc from the Earth should contribute to the observed ultra high energy cosmic ray flux.

7 latex pages, 7 postscript figures included; for related numerical simulations see also http://www.iap.fr/users/sigl/r2e.html

References in corpus (3)

• Transport of Cosmic Rays in Chaotic Magnetic Fields
• Correlation function of ultra-high energy cosmic rays favors point sources
• An Auger test of the Cen A model of highest energy cosmic rays

Cited by in corpus (26)

• Cluster Magnetic Fields
• The Astrophysics of Ultrahigh Energy Cosmic Rays
• Ultra-High Energy Cosmic Ray Probes of Large Scale Structure and Magnetic Fields
• Astrophysical Origins of Ultrahigh Energy Cosmic Rays
• Ultrahigh Energy Cosmic Rays: The state of the art before the Auger Observatory
• Extra-galactic magnetic fields and the second knee in the cosmic-ray spectrum
• Diffusive propagation of UHECR and the propagation theorem
• Ultra-High Energy Cosmic Rays in a Structured and Magnetized Universe
• Stochastic particle acceleration in the lobes of giant radio galaxies
• The optical depth of the Universe to ultrahigh energy cosmic ray scattering in the magnetized large scale structure
• Ultra-High Energy Cosmic Rays from Neutrino Emitting Acceleration Sources?
• SimProp: a Simulation Code for Ultra High Energy Cosmic Ray Propagation
• Analytic calculations of the spectra of ultra-high energy cosmic ray nuclei. I. The case of CMB radiation
• Ultra-High Energy Heavy Nuclei Propagation in Extragalactic Magnetic Fields
• The highest-energy cosmic rays
• Hadronic-Origin TeV gamma-Rays and Ultra-High Energy Cosmic Rays from Centaurus A
• Cosmic Magnetic Fields and Their Influence on Ultra-High Energy Cosmic Ray Propagation
• Large Scale Magnetic Fields and the Number of Cosmic Ray Sources above 10^(19) eV
• The GZK cutoff behind a Magnetized Universe
• The Centaurus A Ultrahigh-Energy Cosmic Ray Excess and the Local Extragalactic Magnetic Field
• New hadrons as ultra-high energy cosmic rays
• Non-Universal Spectra of Ultra-High Energy Cosmic Ray Primaries and Secondaries in a Structured Universe
• Anisotropy at the end of the cosmic ray spectrum?
• Anisotropies of Ultra-high Energy Cosmic Rays Dominated by a Single Source in the Presence of Deflections
• Pierre Auger Data, Photons, and Top-Down Cosmic Ray Models
• Impact of the EPOS.LHC-R hadronic interaction model on the Centaurus A ultrahigh-energy cosmic-ray scenario