Gamma-ray signatures of cosmic ray acceleration, propagation, and confinement in the era of CTA

Abstract

Galactic cosmic rays are commonly believed to be accelerated at supernova remnants via diffusive shock acceleration. Despite the popularity of this idea, a conclusive proof for its validity is still missing. Gamma-ray astronomy provides us with a powerful tool to tackle this problem, because gamma rays are produced during cosmic ray interactions with the ambient gas. The detection of gamma rays from several supernova remnants is encouraging, but still does not constitute a proof of the scenario, the main problem being the difficulty in disentangling the hadronic and leptonic contributions to the emission. Once released by their sources, cosmic rays diffuse in the interstellar medium, and finally escape from the Galaxy. The diffuse gamma-ray emission from the Galactic disk, as well as the gamma-ray emission detected from a few galaxies is largely due to the interactions of cosmic rays in the interstellar medium. On much larger scales, cosmic rays are also expected to permeate the intracluster medium, since they can be confined and accumulated within clusters of galaxies for cosmological times. Thus, the detection of gamma rays from clusters of galaxies, or even upper limits on their emission, will allow us to constrain the cosmic ray output of the sources they contain, such as normal galaxies, AGNs, and cosmological shocks. In this paper, we describe the impact that the Cherenkov Telescope Array, a future ground-based facility for very-high energy gamma-ray astronomy, is expected to have in this field of research.

accepted to Astroparticle Physics, special issue on Physics with the Cherenkov Telescope Array

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Cited by in corpus (16)

• The microphysics of collisionless shock waves
• Anisotropic CR diffusion and gamma-ray production close to supernova remnants, with an application to W28
• Monte Carlo studies for the optimisation of the Cherenkov Telescope Array layout
• Test of the cosmic evolution using Gaussian processes
• Prospects for Observations of Pulsars and Pulsar Wind Nebulae with CTA
• Starburst galaxies as seen by gamma-ray telescopes
• Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants
• Monte Carlo Studies of medium-size telescope designs for the Cherenkov Telescope Array
• On the potential of the Cherenkov Telescope Array for the study of cosmic-ray diffusion in molecular clouds
• The Steady-State Multi-TeV Diffuse Gamma-Ray Emission Predicted with GALPROP and Prospects for the Cherenkov Telescope Array
• High Energy Gamma Rays from Nebulae Associated with Extragalactic Microquasars and Ultra-Luminous X-ray Sources
• Status of the Cherenkov Telescope Array Project
• On the possiblity of using vertically pointing Central Laser Facilities to calibrate the Cherenkov Telescope Array
• Cherenkov telescope array extragalactic survey discovery potential and the impact of axion-like particles and secondary gamma rays
• CTA: the future of ground-based gamma-ray astrophysics
• Acceleration of cosmic rays and gamma-ray emission from supernova remnant/molecular cloud associations