Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2011-12-23
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
18 pages, 7 figures
Scientific paper
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 ~ 10^18 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >~ 10 {\mu}G. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 10^17 eV and 10^18 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E >~ 10^18 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.
Giacinti G.
Kachelriess Michael
Semikoz Dmitri V.
Sigl Guenter
No associations
LandOfFree
Cosmic Ray Anisotropy as Signature for the Transition from Galactic to Extragalactic Cosmic Rays does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Cosmic Ray Anisotropy as Signature for the Transition from Galactic to Extragalactic Cosmic Rays, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cosmic Ray Anisotropy as Signature for the Transition from Galactic to Extragalactic Cosmic Rays will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-192885