
%0 Journal Article
%A Mucke, A 
%A Rachen, JP 
%A Stanev, Todor 
%A Protheroe, RJ 
%A Engel, Ralph 
%T Photohadronic processes in astrophysical environments
%J Publications of the Astronomical Society of Australia
%D 1999/07/01
%V 16
%N 2
%P 160-166
%K 
%R https://doi.org/10.1071/AS99160
%U https://www.publish.csiro.au/paper/AS99160 
%X We discuss the first applications of our newly developed Monte Carlo event generator SOPHIA to multiparticle photoproduction of relativistic protons with thermal and power-law radiation fields. The measured total cross section is reproduced in terms of excitation and decay of baryon resonances, direct pion production, diffractive scattering, and non-diffractive multiparticle production. Non-diffractive multiparticle production is described using a string fragmentation model. We demonstrate that the widely used 'Delta-approximation' for the photoproduction cross section is reasonable only for a restricted set of astrophysical applications. The relevance of this result for cosmic ray propagation through the microwave background and hadronic models of active galactic nuclei and gamma-ray bursts is brie°y discussed. 
