Journal Article

PUBDB-2016-00423

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Reacceleration of electrons in supernova remnants

Pohl, M. (Corresponding author)DESY* ; Wilhelm, A.DESY* ; Telezhinsky, I.DESY*

2015
EDP Sciences Les Ulis

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Please use a persistent id in citations: doi:10.1051/0004-6361/201425027

Report No.: arXiv:1411.2891

Abstract: In this paper we determine the effect of stochastic reacceleration on the spectra of electrons in the GeV band and at lower energies, and we investigate whether reacceleration can explain the observed variation in radio spectral indices.Methods. We explicitely calculated the momentum diffusion coefficient for 3 types of turbulence expected downstream of the forward shock: fast-mode waves, small-scale non-resonant modes, and large-scale modes arising from turbulent dynamo activity. After noting that low-energy particles are efficiently coupled to the quasi-thermal plasma, a simplified cosmic-ray transport equation can be formulated and is numerically solved.Results. Only fast-mode waves can provide momentum diffusion fast enough to significantly modify the spectra of particles. Using a synchrotron emissivity that accurately reflects a highly turbulent magnetic field, we calculated the radio spectral index and find that soft spectra with index α ≲ − 0.6 can be maintained over more than 2 decades in radio frequency, even if the electrons experience reacceleration for only one acceleration time. A spectral hardening is possible but considerably more frequency-dependent. The spectral modification imposed by stochastic reacceleration downstream of the forward shock depends only weakly on the initial spectrum provided by, e.g., diffusive shock acceleration at the shock itself.

Note: (c) ESO. The arXiv version v1 does match with the post referee version.

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Contributing Institute(s):

1. Theoretische Astroteilchenphysik (Z_THAT)

Research Program(s):

1. 523 - High-energy gamma ray astronomy (POF2-523) (POF2-523)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2015

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Database coverage:
; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Preprint/Internal Report Pohl, M. (Corresponding Author)DESY* ; Wilhelm, A.DESY* ; Telezhinsky, I.DESY*
Reacceleration of electrons in supernova remnants
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