Fermi bubbles as sources of cosmic rays above 1 PeV

Dmitry Chernyshov, Kwong Sang Cheng, Vladimir Dogiel, Chung Ming Ko

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Fermi bubbles are giant gamma-ray structures extended north and south of the Galactic center with characteristic sizes of the order of 10 kpc discovered by the Fermi Large Area Telescope. Good correlation between radio and gamma-ray emission in the region covered by Fermi bubbles implies the presence of high-energy electrons in this area. Due to high energy losses it is rather problematic to transfer relativistic electrons from the Galactic disk toward the Fermi bubbles. Therefore it is natural to assume that these electrons are accelerated in-situ. Additionally this acceleration mechanism should also affect protons. In particular it may re-accelerate Galactic cosmic rays produced by supernova remnants. Unlike electrons, protons have huge life-times and therefore re-acceleration should not be a local effect but affect the whole Galaxy. The effect may even be observed near the Earth. In our model we propose that hadronic cosmic rays (CR) below the "knee" of the observed CR spectrum are produced by Galactic supernova remnants distributed in the Galactic disk. Re-acceleration of these particles in Fermi Bubbles produces CRs above the knee. This model provides a natural explanation of the observed CR flux, spectral indices, and matching of spectra at the knee.

Original languageEnglish
Title of host publicationISVHECRI 2016 - 19th International Symposium on Very High Energy Cosmic Ray Interactions
EditorsBryan Pattison
PublisherEDP Sciences
ISBN (Electronic)9782759890187
DOIs
StatePublished - 26 Jun 2017
Event19th International Symposium on Very High Energy Cosmic Ray Interactions, ISVHECRI 2016 - Moscow, Russian Federation
Duration: 22 Aug 201627 Aug 2016

Publication series

NameEPJ Web of Conferences
Volume145
ISSN (Print)2101-6275
ISSN (Electronic)2100-014X

Conference

Conference19th International Symposium on Very High Energy Cosmic Ray Interactions, ISVHECRI 2016
Country/TerritoryRussian Federation
CityMoscow
Period22/08/1627/08/16

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