Probing very high energy cosmic ray (CR) acceleration and the origin of gamma-ray and neutrino emission in Relativistic Jets with PIC-MHD simulations and Machine Learning: Preparing for the ASTRI Mini-Array and the Cherenkov Telescope Array

• Grant number: 22/07971-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: December 01, 2022
• End date: July 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Astronomy
• Principal Investigator: Elisabete Maria de Gouveia Dal Pino
• Grantee: Augusto Rafael Carvalho de Sousa
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/10559-5 - Investigation of high energy and plasma astrophysics phenomena: theory, numerical simulations, observations, and instrument development for the Cherenkov Telescope Array (CTA), AP.ESP

Abstract

Relativistic Jets emanating from Black Holes (BH), especially those from active galaxies, are believed to be among the most extreme particle accelerators and very high energy (VHE) emitters in the universe. Only lately, combining theory, numerical simulations and observations, we have started to understand the potential physical processes that prevail in the surrounds of these BHs in order to explain major puzzles like the origin of the VHE gamma-ray flares and ultra-high-energy cosmic rays (UHECRs). In the inner regions, these systems are dynamically dominated by magnetic fields and Fermi-like particle acceleration driven by magnetic reconnection is expected to prevail. This PhD project aims at extending recent developments in this field performed in our group. The specific objectives involve (i) combining relativistic magnetohydrodynamics (RMHD) simulations with particle-in-cell methods (PIC-RMHD) to account for both particle acceleration and their feedback on the background plasma, which has not been done yet in previous reconnection works; (ii) exploring the origin of VHE gamma-rays and neutrinos, particularly from AGN blazar jets which are frequent gamma-ray emitters, by means of combining RMHD simulations with radiative transfer calculations, as well as using a Monte Carlo approach to build up the blazars's lepto-hadronic spectral energy density (SED); (iii) deploying Machine Learning (ML) algorithms to enhance the speed at which the SEDs are obtained; (iv) applying the results from itens (i)-(iii) to known sources, such as the blazar TXS 0506+056, as well as other targets within the Cherenvok Telescope Array (CTA) and ASTRI Mini-Array collaborations. The student will acquire a large set of skills ranging from numerical techniques to observational ones. An exchange period of 6 months at the Teide Observatory, in Tenerife (Spain), where a hands-on, extensive learning of the operation and employment of the ASTRI Mini-Array is also predicted.