Constraints on cosmological parameters from the EBL attenuation of VHE spectra of extragalactic sources

TL;DR

This paper investigates how the attenuation of very high energy gamma-ray spectra by the Extragalactic Background Light can be used to constrain cosmological parameters, considering recent EBL measurements and future telescope sensitivities.

Contribution

It analyzes the potential of VHE spectra attenuation to provide new constraints on cosmological parameters using current and future observational capabilities.

Findings

Attenuation depends on cosmological parameters and source distance.

Lower EBL levels improve the potential to constrain cosmology.

Future Cherenkov telescopes could detect high-redshift sources for better constraints.

Abstract

The Extragalactic Background Light (EBL) causes attenuation of the VHE spectra of extragalactic sources, via pair-production. The amount of attenuation depends on the distance of the source, i.e. on the integration over the line of sight path taken by the VHE photons. The line of sight path calculation, depends on the values of the cosmological parameters and the evolution of these parameters. With the recent indications of a lower EBL level from observations and the greater sensitivity of the proposed future Cherenkov experiments it will be possible to detect higher redshift sources. We study whether the EBL attenuation of extragalactic sources is sensitive enough to put constrains on the cosmological parameters.