CRPropa: A numerical tool for the propagation of UHE cosmic rays, γ-rays and neutrinos

Abstract

To understand the origin of ultra-high energy cosmic rays (UHECRs, defined to be above 10 18 eV), it is required to model in a realistic way their propagation in the Universe. UHECRs can interact with low energy radio, microwave, infrared and optical photons to produce electron/positron pairs or pions. The latter decay and give rise to neutrinos and electromagnetic cascades extending down to MeV energies. In addition, deflections in cosmic magnetic fields can influence the spectrum and sky distribution of primary cosmic rays and, due to the increased propagation path length, the secondary neutrino and γ−ray fluxes. Neutrino, γ−ray, cosmic ray physics and extra-galactic magnetic fields are, therefore, strongly linked subjects and should be considered together in order to extract maximal information from existing and future data, like the one expected from the Auger Observatory. For that purpose, we have developed CRPropa, a publicly-available numerical package which takes into account interactions and deflections of primary UHECRs as well as propagation of secondary electromagnetic cascades and neutrinos. CRPropa allows to compute the observable properties of UHECRs and their secondaries in a variety of models for the sources and propagation of these particles. Here we present physical processes taken into account as well as benchmark examples; a detailed documentation of the code can be found on our web site.

Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

“…In this work we made use of CRPropa 3.0 4 (Armengaud et al 2007;Kampert et al 2013;Batista et al 2016) which is a publicly available code to simulate the propagation of UHECRs in 3D CMF-simulations. CRPropa injects a particle into a given CMF simulation with some initial momentum and then computes its propagation and energy losses.…”

Enhanced cosmological GRB rates and implications for cosmogenic neutrinos

“…While our simple, analytic method allows for a more transparent look at the effects of source evolution, it does not fully encompass the particle physics involved, particularly the low and high-energy tails of the distributions of particle decays (which affect the low-and high-energy ends of the neutrino spectrum). We utilize the publicly-available simulation package CRPropa [80], which uses the SOPHIA [81] code to handle particle processes, for this purpose. We have made use of the analytical estimate described above and an extensive comparison to previous results presented in the literature (with similar parameters), to verify the results.…”

Ultra High Energy Cosmic Radiation: Experimental and Theoretical Status

“…This is the result of simulations with our public code CRPropa [38], discussed in Ref. [39,40]. For the steep injection spectrum ∝ E −2.7 assumed in Fig.…”