The effect of photon-axion-like particle conversions in galaxy clusters on very high energy {\gamma}-ray spectra
Abstract
Very high energy (VHE, energy >~ 100 GeV) {\gamma}-rays originating from extragalactic sources interact with low energy photons of background radiation fields and produce electron-positron pairs. Alternatively, in the presence of ambient magnetic fields, they can convert into hypothetical axion-like particles (ALPs), pseudo-scalar spin-0 bosons, predicted by extensions of the standard model. These particles propagate unimpeded over cosmological distances. Here, the effect of photon-ALP oscillations in magnetic fields of galaxy clusters and the Milky Way on VHE {\gamma}-ray spectra is studied. It is shown that this mechanism can lead to a substantial enhancement of the VHE flux and a spectral hardening, thus effectively reducing the opacity of the Universe to VHE {\gamma}-rays.
- Publication:
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arXiv e-prints
- Pub Date:
- November 2012
- DOI:
- 10.48550/arXiv.1211.6408
- arXiv:
- arXiv:1211.6408
- Bibcode:
- 2012arXiv1211.6408M
- Keywords:
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- Astrophysics - High Energy Astrophysical Phenomena;
- High Energy Physics - Phenomenology
- E-Print:
- Contributed to the 8th Patras Workshop on Axions, WIMPs and WISPs, Chicago, July 18-22, 2012