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 , and (2) concave breaks in proton and helium spectra at a rigidity . 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 . The similar spectra of CR carbon and helium further suggest that the CRs with 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.
- Received 29 November 2015
DOI:https://doi.org/10.1103/PhysRevD.93.083001
© 2016 American Physical Society