  We discuss simplified models for photo-meson production in cosmic
accelerators, such as Active Galactic Nuclei and Gamma-Ray Bursts. Our
self-consistent models are directly based on the underlying physics used in the
SOPHIA software, and can be easily adapted if new data are included. They allow
for the efficient computation of neutrino and photon spectra (from pi^0
decays), as a major requirement of modern time-dependent simulations of the
astrophysical sources and parameter studies. In addition, the secondaries
(pions and muons) are explicitely generated, a necessity if cooling processes
are to be included. For the neutrino production, we include the helicity
dependence of the muon decays which in fact leads to larger corrections than
the details of the interaction model. The separate computation of the pi^0,
pi^+, and pi^- fluxes allows, for instance, for flavor ratio predictions of the
neutrinos at the source, which are a requirement of many tests of neutrino
properties using astrophysical sources. We confirm that for charged pion
generation, the often used production by the Delta(1232)-resonance is typically
not the dominant process in Active Galactic Nuclei and Gamma-Ray Bursts, and we
show, for arbitrary input spectra, that the number of neutrinos are
underestimated by at least a factor of two if they are obtained from the
neutral to charged pion ratio. We compare our results for several levels of
simplification using isotropic synchrotron and thermal spectra, and we
demonstrate that they are sufficiently close to the SOPHIA software.
