P. Schiffer

CRPropa 2.0 -- a Public Framework for Propagating High Energy Nuclei, Secondary Gamma Rays and Neutrinos

Version 2.0 of CRPropa 1 is public software to model the extra-galactic propagation of ultra-high energy nuclei of atomic number Z 26 through structured magnetic fields and ambient photon backgrounds taking into account all relevant particle interactions. CRPropa covers the energy range 6 10 16 < E=eV < A 10 22 where A is the nuclear mass number. CRPropa can also be used to track secondary -rays and neutrinos which allows the study of their link with the charged primary nuclei ‐ the so called multi-messenger connection. After a general introduction we present several sample applications of current interest concerning the physics of extragalactic ultra-high energy radiation.

PARSEC: A Parametrized Simulation Engine for Ultra-High Energy Cosmic Ray Protons

Abstract We present a new simulation engine for fast generation of ultra-high energy cosmic ray data based on parametrizations of common assumptions of UHECR origin and propagation. Implemented are deflections in unstructured turbulent extragalactic fields, energy losses for protons due to photo-pion production and electron-pair production, as well as effects from the expansion of the universe. Additionally, a simple model to estimate propagation effects from iron nuclei is included. Deflections in the Galactic magnetic field are included using a matrix approach with precalculated lenses generated from backtracked cosmic rays. The PARSEC program is based on object oriented programming paradigms enabling users to extend the implemented models and is steerable with a graphical user interface.

Propagation of UHECRs in the universe

Abstract The origin, propagation, and mechanisms of acceleration of the ultra-high energy cosmic rays (UHECRs) are not yet well understood. Aiming for a better interpretation of the available experimental data, these data have to be confronted with theoretical models. A realistic simulation of the propagation of UHECRs in the universe should take into account all the relevant energy loss processes due to the interaction with astrophysical backgrounds, as well as the intervening cosmic magnetic fields. Cosmological effects, such as the redshift dependence of the photon backgrounds and the adiabatic expansion of the universe, can play an important role in the aforementioned processes. Here we present results of simulations of the propagation of UHECR through the large scale structure of the universe considering cosmological and magnetic field effects simultaneously.

A Hybrid Monte Carlo Generator for Ultra-High Energy Cosmic Rays from their Sources to the Observer

To understand in detail cosmic magnetic fields and sources of Ultra-High Energy Cosmic Rays (UHECRs) we have developed a Monte Carlo simulation for galactic and extragalactic propagation. In our approach we identify three different propagation regimes for UHECRs, the Milky Way, the local universe out to 110 Mpc, and the distant universe. For deflections caused by the galactic magnetic field a lensing technique based on matrices is applied which are created from backtracking of antiparticles through galactic field models. Propagation in the local universe uses forward tracking through structured magnetic fields extracted from simulations of the large scale structure of the universe. UHECRs from distant sources are simulated using parameterized models. In this contribution we present the combination of all three simulation techniques by means of probability maps. The combined probability maps are used to generate a large number of UHECRs, and to create distributions from approximately realistic universe scenarios. Comparisons with physics analyses of UHECR measurements enable the development of new analysis techniques and help to constrain parameters of the underlying physics models like the source density and the magnetic field strength in the universe.