Magnetic Deflections of Ultra-High Energy Cosmic Rays from Centaurus A

Abstract

We present the results of a study that simulates trajectories of ultra-high energy cosmic rays from Centaurus A to Earth, for particle rigidities from $E/Z=2$ EV to 100 EV, i.e., covering the possibility of primary particles as heavy as Fe nuclei with energies exceeding 50 EeV. The Galactic magnetic field is modeled using the recent work of Jansson and Farrar (JF12) which fitted its parameters to match extragalactic Faraday rotation measures and WMAP7 synchrotron emission maps. We include the random component of the GMF using the JF12 3D model for $B_{\mathrm{rand}}(\vec{r})$ and explore the impact of different random realizations, coherence length and other features on cosmic ray deflections. Gross aspects of the arrival direction distribution such as mean deflection and the RMS dispersion depend mainly on rigidity and differ relatively little from one realization to another. However different realizations exhibit non-trivial substructure whose specific features vary considerably from one realization to another, especially for lower rigidities. At the lowest rigidity of 2 EV, the distribution is broad enough that it might be compatible with a scenario in which Cen A is the principle source of all UHECRs. No attempt is made here to formulate a robust test of this possibility, although some challenges to such a scenario are noted.

20 pages, 9 figures, 1 table; submitted to Astroparticle Physics

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Cited by in corpus (9)

• 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: The Intersection of the Cosmic and Energy Frontiers
• The Nuclear Window to the Extragalactic Universe
• Angular Power Spectra with Finite Counts
• Anisotropies of ultrahigh-energy cosmic rays in a scenario with nearby sources
• Near-future discovery of point sources of ultra-high-energy neutrinos
• Case for Centaurus A as the main source of ultrahigh-energy cosmic rays
• Modelling Cosmic Rays Flux with Pierre Auger and Telescope Array Data in $\mathbf{f}(\mathbf{R})$ and $\mathbf{f}(\mathbf{Q})$ Theories of Gravity
• Displacement of ultra-high-energy cosmic ray source images by the intergalactic magnetic field: the cases of Cen A and M83