On the potential of the Cherenkov Telescope Array for the study of cosmic-ray diffusion in molecular clouds

Abstract

Molecular clouds act as primary targets for cosmic-ray interactions and are expected to shine in gamma-rays as a by-product of these interactions. Indeed several detected gamma-ray sources both in HE and VHE gamma-rays (HE: 100 MeV < E < 100 GeV; VHE: E > 100 GeV) have been directly or indirectly associated with molecular clouds. Information on the local diffusion coefficient and the cosmic-ray population can be inferred from the observed gamma-ray signals. In this work we explore the capability of the forthcoming Cherenkov Telescope Array Observatory (CTA) to provide such measurements. We investigate the expected emission from clouds hosting an accelerator, surveying the parameter space for different modes of acceleration, age of the source, cloud density profile, and cosmic-ray diffusion coefficient. We present some of the most interesting cases for CTA regarding this science topic. The simulated gamma-ray fluxes depend strongly on the input parameters. In several cases, we find that it will be possible to constrain both the properties of the accelerator and the propagation mode of cosmic rays in the cloud from CTA data alone.

10 pages, 10 figures, 1 table, accepted for publication in A&A

References in corpus (7)

• Teraelectronvolt Astronomy
• Gamma rays from molecular clouds
• Surveys with the Cherenkov Telescope Array
• Fermi LAT study of cosmic-rays and the interstellar medium in nearby molecular clouds
• The GeV-TeV Connection in Galactic gamma-ray sources
• Gamma-ray signatures of cosmic ray acceleration, propagation, and confinement in the era of CTA
• Gamma Ray Astronomy and the Origin of Galactic Cosmic Rays

Cited by in corpus (5)

• Probing Cosmic Rays in Nearby Giant Molecular Clouds with the Fermi Large Area Telescope
• Fermi-LAT observations of the Sagittarius B complex
• Molecular environment, reverberation, and radiation from the pulsar wind nebula in CTA 1
• Runaway stars as cosmic ray injectors inside molecular clouds
• On the possible correlation of Galactic VHE source locations and enhancements of the surface density in the Galactic plane