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arXiv · 1709.04185

Studying cosmological $\gamma$-ray propagation with the Cherenkov Telescope Array

Florian Gaté·Rafael Alves Batista·Jonathan Biteau·Julien Lefaucheur·Salvatore Mangano·Manuel Meyer·Quentin Piel·Santiago Pita·David Sanchez·Ievgen Vovk
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Abstract

The measurement of $\gamma$-rays originating from active galactic nuclei offers the unique opportunity to study the propagation of very-high-energy photons over cosmological distances. Most prominently, $\gamma$-rays interact with the extragalactic background light (EBL) to produce $e^+e^-$ pairs, imprinting an attenuation signature on $\gamma$-ray spectra. The $e^+e^-$ pairs can also induce electromagnetic cascades whose detectability in $\gamma$-rays depends on the intergalactic magnetic field (IGMF). Furthermore, physics beyond the Standard Model such as Lorentz invariance violation (LIV) or oscillations between photons and weakly interacting sub-eV particles (WISPs) could affect the propagation of $\gamma$-rays. The future Cherenkov Telescope Array (CTA), with its unprecedented $\gamma$-ray source sensitivity, as well as enhanced energy and spatial resolution at very high energies, is perfectly suited to study cosmological effects on $\gamma$-ray propagation. Here, we present first results of a study designed to realistically assess the capabilities of CTA to probe the EBL, IGMF, LIV, and WISPs.

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Florian Gaté, Rafael Alves Batista, Jonathan Biteau, Julien Lefaucheur, Salvatore Mangano, Manuel Meyer, Quentin Piel, Santiago Pita, David Sanchez, Ievgen Vovk. 2017-09-13. Studying cosmological $\gamma$-ray propagation with the Cherenkov Telescope Array. https://arxiv.org/abs/1709.04185

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