Cosmic-ray hardenings in light of AMS-02 data

Yutaka Ohira, Norita Kawanaka, and Kunihito Ioka
Phys. Rev. D 93, 083001 – Published 1 April 2016

Abstract

Recent precise observations of cosmic rays (CRs) by AMS-02 experiment clearly show (1) harder spectra of helium and carbon compared to protons by R0.08, and (2) concave breaks in proton and helium spectra at a rigidity R300GV. In particular the helium and carbon spectra are exactly similar, pointing to the same acceleration site. We examine possible interpretations of these features and identify a chemically enriched region, that is, superbubbles as the most probable origin of Galactic CRs in high rigidity R>30GV. The similar spectra of CR carbon and helium further suggest that the CRs with R>30GV originate from the supernova ejecta in the superbubble core, mixed with comparable or less amount of interstellar medium. We predict similar spectra for heavy nuclei.

  • Figure
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  • Received 29 November 2015

DOI:https://doi.org/10.1103/PhysRevD.93.083001

© 2016 American Physical Society

Physics Subject Headings (PhySH)

Particles & FieldsGravitation, Cosmology & Astrophysics

Authors & Affiliations

Yutaka Ohira1,*, Norita Kawanaka2, and Kunihito Ioka3,4

  • 1Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 252-5258, Japan
  • 2Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
  • 3Theory Center, Institute of Particle and Nuclear Studies, KEK, Tsukuba 305-0801, Japan
  • 4Department of Particle and Nuclear Physics, SOKENDAI (the Graduate University for Advanced Studies), Tsukuba 305-0801, Japan

  • *ohira@phys.aoyama.ac.jp

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Issue

Vol. 93, Iss. 8 — 15 April 2016

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