Issue |
A&A
Volume 546, October 2012
|
|
---|---|---|
Article Number | A120 | |
Number of page(s) | 13 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361/201219770 | |
Published online | 18 October 2012 |
The time-dependent one-zone hadronic model
First principles
1
Department of PhysicsUniversity of Athens,
Panepistimiopolis,
15783
Zografos,
Greece
e-mail: sdimis@phys.uoa.gr
2
Department of Physics (School of Chemistry and Physics),
University of Adelaide, North
Terrace, Adelaide,
SA
5005,
Australia
3 Institut für Theoretische Physik, und Institut für Astro- und
Teilchenphysik, Universität Innsbruck, Austria
Received: 6 June 2012
Accepted: 6 August 2012
We present a time-dependent approach to the one-zone hadronic model in the case where the photon spectrum is produced by ultrarelativistic protons interacting with soft photons that are produced from protons and low magnetic fields. Assuming that protons are injected at a certain rate in a homogeneous spherical volume containing a magnetic field, the evolution of the system can be described by five coupled kinetic equations, for protons, electrons, photons, neutrons, and neutrinos. Photopair and photopion interactions are modelled using the results of Monte-Carlo simulations and, in particular, from the SOPHIA code for the latter. The coupling of energy losses and injection introduces a self-consistency in our approach and allows the study of the comparative relevancy of processes at various conditions, the efficiency of the conversion of proton luminosity to radiation, the resulting neutrino spectra, and the effects of time variability on proton injection, among other topics. We present some characteristic examples of the temporal behaviour of the system and show that this can be very different from the one exhibited by leptonic models. Furthermore, we argue that, contrary to the wide-held belief, there are parameter regimes where the hadronic models can become quite efficient. However, to keep the free parameters at a minimum and facilitate an in-depth study of the system, we have only concentrated on the case where protons are injected; i.e., we did not consider the effects of a co-accelerated leptonic component.
Key words: radiation mechanisms: non-thermal / radiative transfer / galaxies: active
© ESO, 2012
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