Speaker
Description
Before and during cosmic reionization, the universe is filled with small gaseous structures, e.g. minihalos (with halo mass between 10^4 and 10^8 solar mass). These structures can influence the 21cm signal and slow down the ionization fronts during cosmic reionization.
To investigate their influence, we perform high resolution cosmological simulations using our newly-developed moment-based radiation hydrodynamics method in the SWIFT astrophysical code. We found these small-scale structures can boost recombination rates significantly during the first 100 Myrs after the passage of an ionization front. They can also boost the required number of photons to ionize the universe by a factor of two, compared to the uniform medium.
We are currently extending our study to include the effect of background density using the separate universe simulation technique. Furthermore, we explore the effects of additional physics, e.g. different inflation and dark matter models, on these small gaseous structures. These will provide us valuable probes of cosmology and astrophysics by combining these theoretical prediction and 21cm/reionization observations.
