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

Nir J. Shaviv, Ehud Nakar, and Tsvi Piran
Phys. Rev. Lett. 103, 111302 – Published 10 September 2009

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 100GeV, leading to the relatively flat spectrum observed by Fermi and to the sharp cutoff observed by H.E.S.S.

  • Figure
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  • Received 16 April 2009

DOI:https://doi.org/10.1103/PhysRevLett.103.111302

©2009 American Physical Society

Authors & Affiliations

Nir J. Shaviv1, Ehud Nakar2, and Tsvi Piran1

  • 1Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel
  • 2The Raymond and Beverly Sackler School of Physics & Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel

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Vol. 103, Iss. 11 — 11 September 2009

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