CTA sensitivity for probing cosmology and fundamental physics with gamma rays

TL;DR

The CTA observatory will significantly advance gamma-ray cosmology and fundamental physics by measuring gamma-ray absorption, probing intergalactic magnetic fields, testing physics beyond the Standard Model, and exploring dark matter candidates.

Contribution

This paper demonstrates CTA's potential to improve constraints on gamma-ray absorption, intergalactic magnetic fields, Lorentz invariance violation, and axion-like particles through simulations.

Findings

CTA will measure gamma-ray absorption with <15% error up to z=2

Detect or limit gamma halos from intergalactic magnetic fields of ≥0.3 pG

Improve constraints on Lorentz invariance violation by 2-3 times

Abstract

The Cherenkov Telescopic Array (CTA), the next-generation ground-based gamma-ray observatory, will have unprecedented sensitivity, providing answers to open questions in gamma-ray cosmology and fundamental physics. Using simulations of active galactic nuclei observations foreseen in the CTA Key Science Program, we find that CTA will measure gamma-ray absorption on the extragalactic background light with a statistical error below 15% up to the redshift of 2 and detect or establish limits on gamma halos induced by the intergalactic magnetic field of at least 0.3 pG. Extragalactic observations using CTA also demonstrate the potential for testing physics beyond the Standard Model. The best state-of-the-art constraints on the Lorentz invariance violation from astronomical gamma-ray observations will be improved at least two- to threefold. CTA will also probe the parameter space where axion-like particles can represent a significant proportion - if not all - of dark matter. Joint multiwavelength and multimessenger observations, carried out together with other future observatories, will further foster the growth of gamma-ray cosmology.