Constraining the Equation of State of Dark Energy with Gamma Rays

TL;DR

This paper proposes a novel method to constrain dark energy's equation of state by analyzing gamma-ray attenuation caused by stellar photon fields, linking cosmology with high-energy astrophysics.

Contribution

It introduces a new approach that uses gamma-ray observations to infer properties of dark energy, complementing existing cosmological probes.

Findings

Demonstrates the feasibility of using gamma-ray attenuation to constrain dark energy.

Outlines the necessary steps for a rigorous statistical implementation.

Provides a proof of concept for this novel method.

Abstract

Starlight in the Universe impedes the passage of high energy (e.g. TeV) gamma rays due to positron-electron pair production. The history of this stellar radiation field depends upon observations of star formation rate which themselves can only be interpreted in the context of a particular cosmology. For different equations of state of dark energy, the star formation rate data suggests a different density of stellar photons at a particular redshift and a different probability of arrival of gamma rays from distant sources. In this work we aim to show that this effect can be used to constrain the equation of state of dark energy. The current work is a proof of concept and we outline the steps that would have to be taken to place the method in a rigorous statistical framework which could then be combined with other more mature methods such as fitting supernova luminosity distances.