EPJ Web of Conferences
Volume 53, 2013UHECR 2012 - International Symposium on Future Directions in UHECR Physics
|Number of page(s)||7|
|Section||Cosmic Ray Sources and Propagation|
|Published online||25 June 2013|
Transition from Galactic to extragalactic cosmic rays and cosmic ray anisotropy
1 IInstitutt for fysikk, NTNU, Trondheim, Norway
2 AstroParticle and Cosmology (APC), Paris, France
3 Institut für Theoretische Physik, Universität Hamburg, Germany
a e-mail: firstname.lastname@example.org
This talk based on results of ref. , where we constrain the energy at which the transition from Galactic to extragalactic cosmic rays occurs by computing the anisotropy at Earth of cosmic rays emitted by Galactic sources. Since the diffusion approximation starts to loose its validity for E/Z ≳ 10(16−17) eV, we propagate individual cosmic rays using Galactic magnetic field models and taking into account both their regular and turbulent components. The turbulent field is generated on a nested grid which allows spatial resolution down to fractions of a parsec. If the primary composition is mostly light or intermediate around E ∼ 1018 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >10 μG. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 1017 eV and 1018 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E > 1018 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.