Evidence for Secondary Emission as the Origin of Hard Spectra in TeV Blazars
Abstract
We develop a model for the possible origin of hard, very high energy (VHE) spectra from a distant blazar. In the model, both the primary photons produced in the source and secondary photons produced outside it contribute to the observed high-energy γ-ray emission. That is, the primary photons are produced through the synchrotron self-Compton process, and the secondary photons are produced through high-energy proton interactions with background photons along the line of sight. We apply the model to a characteristic case of VHE γ-ray emission in the distant blazar 1ES 1101-232. Assuming suitable electron and proton spectra, we obtain excellent fits to the observed spectra of this blazar. This indicated that the surprisingly low attenuation of the high-energy γ-rays, especially the shape of the VHE γ-ray tail of the observed spectra, can be explained by secondary γ-rays produced in interactions of cosmic-ray protons with background photons in intergalactic space.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2013
- DOI:
- 10.1088/0004-637X/764/2/113
- arXiv:
- arXiv:1609.09148
- Bibcode:
- 2013ApJ...764..113Z
- Keywords:
-
- BL Lacertae objects: individual: 1ES 1101-232;
- radiation mechanisms: non-thermal;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 5 pages, 2 figures, published in ApJ (2013ApJ...764..113Z)