Seminar:- The Impact of Intergalactic Medium and Halos on Reionization
Reionization refers to a cosmic event where the neutral intergalactic medium(IGM) was ionized by luminous galaxies and quasars. This event is central to galaxy evolution and cosmic structure, so it is the main focus of many observations, including James Webb Space Telescope(JWST) and Square Kilometre Array(SKA). However, the progress of reionization depended on the sinks of ionizing photons. Dense gas in the IGM and halos absorb more photons due to fast recombination. To understand them, we required high resolution cosmological simulations with radiation hydrodynamics. To achieve this, The speaker used his novel, adaptive, and efficient radiation hydrodynamics method, Smoothed Particle Hydrodynamics - Radiative Transfer Method(SPH-M1RT). He have coupled this method to the state-of-the-art cosmological simulation code, SWIFT. He and his team find that minihalos(halos with virial temperature below 104 K) can be important sinks, although they photo-evaporate within around 100 Myr. These sinks boost the required reionization photon budget by 20-100%, depending on the reionization redshift and photo-ionization rates. Finally, the speaker will discuss other applications and recent developments of SPH-M1RT in astrophysical simulations.
講者：陳增强 博士 Dr. CHAN Tsang Keung(Department of Physics Durham University, UK)