Abstact: Cosmic reionisation transformed the intergalactic medium from a cold, neutral gas into an ionised plasma, driven first by stars and later by black holes. I will present LUMINA, which follows hydrogen and helium reionisation down to z = 3 in a 500 cMpc box, combining the IllustrisTNG galaxy formation model with GPU-accelerated radiation transport. I will discuss the reionisation histories, morphology, and cosmic variance. I will also present a new GPU-based solver for self-interacting dark matter and its gravothermal collapse, which could explain the unusually dense dark matter substructures inferred from perturbations of gravitational lenses and stellar streams.
Short bio: Oliver Zier is an ITC Fellow at the Center for Astrophysics | Harvard & Smithsonian. He completed his PhD on simulations of accretion disks at the Max Planck Institute for Astrophysics in 2023 under the supervision of Volker Springel, followed by a postdoctoral position at MIT with Mark Vogelsberger. His research focuses on the early Universe through the Lumina project and on self-interacting dark matter. He is one of the main authors of GADGET-4 and AREPO-2 and develops numerical methods and GPU acceleration techniques to enable these studies.