Joost de Kleuver
Joost de Kleuver is a fourth-year PhD student in astrophysics at Radboud University in Nijmegen. Under the supervision of Heino Falcke, he uses theoretical methods to develop new ways of studying the rotation, or “spin,” of supermassive black holes in the context of the Event Horizon Telescope. One of his projects focuses on recovering black hole spin from the gravitationally lensed images of bright flares (hot spots) orbiting the black hole, using ray-tracing in curved spacetimes. Another line of research involves producing high-resolution, long-duration general relativistic magnetohydrodynamic (GRMHD) plasma simulations of black holes, enabling new insights into accretion physics, jet launching, and strong-field gravitational physics.
Session
Simulations of black holes have been essential in the lead-up to, and interpretation of, the first-ever images of black holes made by the Event Horizon Telescope. As we prepare for the next step, towards the first movies of these systems, numerical simulations must take a similar leap forward. For this, we need and exploit the power of next-generation HPC systems such as LUMI. Using the general relativistic magnetohydrodynamics (GRMHD) code HAMR, optimized for massively parallel architectures, we study the plasma and magnetic fields close to the black hole, and achieve orders-of-magnitude improvements in resolution and physical fidelity. This enables us to probe new regimes in black hole astrophysics, spanning accretion physics, jet launching, and strong-field gravitational physics.
In this talk, I will outline the central role of HPC in black hole astrophysics, share first-hand experience from large-scale runs on LUMI, and present an early glimpse of the physical insights that become accessible with this capability.