Tracing cosmic-ray acceleration in galaxy clusters: cosmological MHD simulation and Lagrangian tracers
Kosuke Nishiwaki (INAF - IRA Bologna)
Tuesday 28/01/2025 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
The diffuse radio emission observed in galaxy clusters and cosmic filaments indicates that the relativistic particles are accelerated in the inter-galactic environment. The large extent and the steep-spectrum nature of the radio synchrotron emission are compatible with the turbulent (Fermi II) acceleration model. However, there remain so many unresolved questions; what is the origin of “seed” particles prior to turbulent acceleration, what is the impact of cosmic-ray protons, etc. Recent and near-future advancements in radio observation enable us to study the emission with enhanced frequency range, sensitivity, and angular resolution, which offers important hints to those unsolved questions. The cosmological magneto-hydrodynamical (MHD) simulation together with the Lagrangian tracer method allow us a comprehensive modeling of those radio emission, thereby enabling a theoretical study using the detailed observations. I will present our recent results on a radio halo reproduced with this method and discuss some constraints on the origin of relativistic particles.