Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-11-04
Phys.Rev.D79:083010,2009
Astronomy and Astrophysics
Astrophysics
Accepted for publication in PRD, 12 pages, 9 figures
Scientific paper
10.1103/PhysRevD.79.083010
With the prospect of measuring the fraction of arriving secondary photons, produced through photo-pion energy loss interactions of ultra high energy cosmic ray (UHECR) protons with the microwave background during propagation, we investigate how information about the local UHECR source distribution can be inferred from the primary (proton) to secondary (photon) ratio. As an aid to achieve this, we develop an analytic description for both particle populations as a function of propagation time. Through a consideration of the shape of the GZK cut-off and the corresponding photon fraction curve, we investigate the different results expected for both different maximum proton energies injected by the sources, as well as a change in the local source distribution following a perturbative deformation away from a homogeneous description. At the end of the paper, consideration is made as to how these results are modified through extra-galactic magnetic field effects on proton propagation. The paper aims to demonstrate how the shape of the cosmic ray flux in the cut-off region, along with the photon fraction, are useful indicators of the cutoff origin as well as the local UHECR source distribution.
Aharonian Felix A.
Taylor Andrew M.
No associations
LandOfFree
The Spectral Shape and Photon Fraction as Signatures of the GZK-Cutoff 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 The Spectral Shape and Photon Fraction as Signatures of the GZK-Cutoff, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Spectral Shape and Photon Fraction as Signatures of the GZK-Cutoff will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-183515