The proton blazar.
Abstract
Recent gamma ray detections and the radio/X-ray correlation of extragalactic flat-spectrum radio sources make the existence of an ultra-relativistic proton population in jets very probable. The protons with maximum Lorentzfactors in the range 10^9^ - 10^11^ generate hard photons with energies from keV to TeV via pion and pair photoproduction and subsequent synchrotron cascade reprocessing. In this paper relativistic protons are considered in the context of the Blandford & Konigl (1979) model of compact radio jets which are assumed to be responsible for the nonthermal emission component of flat-spectrum quasars and BL Lacertids. The baryons are simply added to the electrons considered as the only radiative agent in the original work. The differential gamma ray spectrum induced by the protons is an inverse powerlaw with an index preferentially in the range 1.8 to 2.0. Below a few MeV the spectrum flattens to an X-ray spectrum with index 1.5 to 1.7. For a given energy flux through a jet the apparent radio luminosity is lower for a relativistic proton enriched plasma than for a relativistic electron enriched plasma (i.e. for jets with a proton/electron energy density ratio n = u_p_/u_e_ > 1), while the apparent gamma ray luminosity is almost constant. Differential Doppler-boosting i.e. changes in flux amplification due to changes in the orientation of the radiating plasma element, influences the pair creation optical depth and therefore has an effect on the maximum photon energies of the compact radio source. Hence TeV emission should correlate with high states of the entire continuum flux. Further consequences are a) an observable diffuse flux of neutrinos with a flat spectrum in the PeV-EeV range, b) a diffuse flux of gamma rays equal to the flux of gamma rays from the Milky Way at an energy of 7 TeV, c) neutrons escaping the blazar that convert their luminosity in the kinetic power of a conical wind surrounding the jet or escape the host galaxy at highest energies.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1993
- arXiv:
- arXiv:astro-ph/9302006
- Bibcode:
- 1993A&A...269...67M
- Keywords:
-
- Blazars;
- Extragalactic Radio Sources;
- Gamma Ray Astronomy;
- Proton Density (Concentration);
- Bl Lacertae Objects;
- Radio Astronomy;
- X Ray Astronomy;
- Astrophysics;
- Astrophysics;
- High Energy Physics - Phenomenology
- E-Print:
- 9 pages, plaintex C, Version 3.0