PRIN 2022 - COD. 2022C9TNNX - "Virtual and real observations of high-energy astrophysical sources in the exa-scale era." - Finanziamento dell’Unione Europea – NextGenerationEU – missione 4, componente 2, investimento 1.1.

This project targets high-energy astrophysical environments (with a major focus on extragalactic jets) with the aim of bridging theoretical astrophysics, numerical simulations and observations under a unified cross-scale view on magnetohydrodynamics, plasma kinetics and non-thermal emission. Successful achievement calls for huge computational resources that will become accessible once the proposed numerical framework has been empowered to target the upcoming exa-scale technology. The project realization leans on the expertise of the UniTo and INAF research units with the following goals: i) advance the current state-of-the-art computational framework by including sub-grid modeling of particle acceleration in reconnecting magnetized current sheets; ii) enabling exa-scale numerical simulations through GPU technology; iii) perform cutting-edge numerical simulations interconnecting virtual and real observations, in order to address the problems of energy dissipation, particle acceleration and dynamics. Key to the project is to determine the role of shocks vs. magnetic reconnection energization for the production of ultra-relativistic particles. In this plan, energy efficiency is a primary concern in the design of future exa-scale platforms, aiming at delivering new high-performance computing (HPC) standards with considerable reduction in power consumption (more than a factor of 10). In this sense, the increasing employment of Graphical Processor Units (GPU) in modern clusters undoubtedly represents a successful step in the exa-scale roadmap. The project will be largely based on the hybrid fluid-particle module available with the PLUTO code for astrophysical plasma dynamics, developed by the UniTo group. Besides the already present sub-grid modeling of particle acceleration at shocks, we further aim at incorporating acceleration mechanisms from relativistic magnetic reconnection. The need of sub-grid modeling is evident when considering the huge spatial disparity separating the large system parsec-scales of interest from the small kinetic scales, where particle acceleration takes place. The comparison of simulation results with real observations will rely on big databases storing multiwavelength information provided by many ground- and space-based facilities. In the next future, unprecedented observations will come from the Cherenkov Telescope Array (CTA), exploring the most energetic gamma-rays, and from the Rubin Observatory’s Legacy Survey of Space and Time (LSST) in the optical band. The final outcome will provide an innovative contribution to the field of extragalactic jets and high-energy astrophysical contexts in general, by allowing observable quantities to be extracted from advanced numerical simulations for a direct comparison with observational data.