Formation of the Cosmic-Ray Halo: Galactic Spectrum of Primary Cosmic Rays
| Autor: | Chung Ming Ko, A. V. Ivlev, Dmitrii Chernyshov, V. A. Dogiel |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Physics 010504 meteorology & atmospheric sciences High-energy astronomy Scattering FOS: Physical sciences Astronomy and Astrophysics Cosmic ray Astrophysics::Cosmology and Extragalactic Astrophysics Plasma Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Redshift Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Halo Magnetohydrodynamics Disc Astrophysics - High Energy Astrophysical Phenomena 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences |
| Zdroj: | The Astrophysical Journal. 903:135 |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/1538-4357/abba31 |
| Popis: | A self-consistent model of a one-dimensional cosmic-ray (CR) halo around the Galactic disk is formulated with the restriction to a minimum number of free parameters. It is demonstrated that the turbulent cascade of MHD waves does not necessarily play an essential role in the halo formation. Instead, an increase of the Alfven velocity with distance to the disk leads to an efficient generic mechanism of the turbulent redshift, enhancing CR scattering by the self-generated MHD waves. As a result, the calculated size of the CR halo at lower energies is determined by the halo sheath, an energy-dependent region around the disk beyond which the CR escape becomes purely advective. At sufficiently high energies, the halo size is set by the characteristic thickness of the ionized gas distribution. The calculated Galactic spectrum of protons shows a remarkable agreement with observations, reproducing the position of spectral break at ~ 0.6 TeV and the spectral shape up to ~ 10 TeV. Comment: 10 pages, 3 figures; accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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