Inhomogeneity in Cosmic Ray Sources as the Origin of the Electron Spectrum and the PAMELA Anomaly

2009/02/28 by Nir J. Shaviv, Ehud Nakar, Tsvi Piran · 5 citations
Physics and Astronomy · #Anomaly (physics) #Astrophysics #Astrophysics and Cosmic Phenomena #COSMIC cancer database #Condensed matter physics #Cosmic ray #Cutoff #Dark Matter and Cosmic Phenomena #Electron #Fermi Gamma-ray Space Telescope #Galactic Center #Galaxy #Neutrino Physics Research #Nuclear physics #Physics #Positron #Spectrum (functional analysis) #Supernova #Supernova remnant #astro-ph.HE #hep-ph

paper · pdf · doi:10.1103/physrevlett.103.111302

published as Phys.Rev.Lett.103:111302,2009

arxiv created 2009/04/16 · openalex publication_date 2009/09/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We show that inhomogeneity of cosmic ray (CR) sources, due to the concentration of supernova remnants (SNRs) towards the galactic spiral arms, can naturally explain the anomalous increase in the positron/electron ratio observed by PAMELA. We consistently recover the observed positron fraction between 1 and 100 GeV using SNRs as the sole source of CRs. The contribution of a few known nearby SNRs dominates the CR electron spectrum above approximately 100 GeV, leading to the relatively flat spectrum observed by Fermi and to the sharp cutoff observed by H.E.S.S.

Citations

• The spiral structure of the Milky Way, cosmic rays, and ice age epochs on Earth
• TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess
• Pulsars as the sources of high energy cosmic ray positrons
• New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV
• Particle acceleration at astrophysical shocks: A theory of cosmic ray origin
• Energy Spectrum of Cosmic-Ray Electrons at TeV Energies

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• ORIGIN OF THE COSMIC RAY POSITRONS OBSERVED NEAR EARTH: MESON DECAY OR DARK MATTER DECAY?