http://arxiv.org/abs/1510.03672
We present a systematic study of the non-thermal electron-proton plasma and its emission processes in starburst galaxies in order to explain the correlation between the luminosity in the radio band and the recently observed gamma luminosity. In doing so, a steady state description of the non-thermal electrons and protons within the spatially homogeneous starburst is considered where continuous momentum losses are included as well as catastrophic losses due to diffusion and advection. The primary source of the relativistic electron-proton plasma, e.g. supernova remnants, provides a quasi-neutral plasma with a power law spectrum in momentum where we account for rigidity dependent differences between the electron and proton spectrum. We examine the resulting leptonic and hadronic radiation processes by synchrotron radiation, inverse Compton scattering, Bremsstrahlung and hadronic pion production. Finally, the observations of NGC 253, M 82, NGC 4945 and NGC 1068 in the radio and gamma-ray band are used to constrain a best-fit model, that is subsequently used to determine the corresponding supernova rate, the calorimetric behavior as well as the expected neutrino flux. It is shown that the primary electron source spectrum at high energies needs to be steepened by inverse Compton (or synchrotron) losses. Furthermore, secondary electrons are important to model the radio flux, especially in the case of M 82. Another important result is that supernovae can not be the dominant source of relativistic particles in NGC 4945 and NGC 1068 and the relativistic particle outflow in all considered starburst galaxies consists of protons that are driven by the diffusion.
B. Eichmann and J. Tjus
Wed, 14 Oct 15
56/66
Comments: N/A
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