Diffusive shock acceleration in Galactic sources

• Grant number: 22/16530-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2023
• End date: December 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Astronomy
• Principal Investigator: Maria Victoria Del Valle
• Grantee: Gabriel Cassoli Capellini
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/05757-9 - Nonthermal processes in galactic sources: modelling and predictions in the CTAs and ASTRI Mini-Arrays eve, AP.JP

Abstract

Galactic cosmic rays are believed to be accelerated in shocks via diffusive shock acceleration. This first order Fermi mechanism occurs in shock waves produced in astrophysical sources and in the interstellar medium. Shock waves develop when supersonic perturbations propagate in a medium and are ubiquitous in the Galaxy. Additionally, under the appropriate conditions particles can be efficiently accelerated in a first order Fermi acceleration process operating in magnetic reconnection sites. The maximum energy that particles can achieve in the acceleration process, the shape of the particle spectra and the total flux in high-energy (accelerated) particles depend on the source properties such as size, magnetic field, density, etc.- and on the shock characteristics such as velocity. Galactic sources have different capabilities for particle acceleration, and hence for producing non-thermal emission. The gamma-ray radiation of active sources depends strongly on the details of the acceleration mechanisms, and its production depends on the ability of sources to accelerate particles up to relativistic energies. The main goal of this Scientific Initiation plan is the investigation of the particle acceleration mechanisms operating in Galactic sources and the non-thermal emission produced, with special emphasis on diffusive shock acceleration. The theory will be applied to Galactic sources with different properties such as colliding-wind binaries, high-velocity clouds, etc. The project also contemplates the study of the potential detectability of the modelled sources at gamma rays.