The 21 cm cosmology and cosmic reionization simulations

The epoch of reionization is a period in the history of the Universe during which the intergalactic hydrogen gas went from neutral to ionized when the Universe was a few hundred million to a billion years old (corresponding to the redshift 6<z<30). This event was powered by the emergence of the first luminous objects from which energetic ultraviolet and X-ray photons were released to ionize the surrounding intergalactic medium. Associated with this process is a rich set of astrophysical processes, the competition of which derives the characteristic rises and falls in the signal of 21-cm brightness temperature as a function of the observed frequency. Detection of these characteristics through 21-cm observations will flag the formation time of the first luminous objects, and provide unique constraints on their physical conditions at the early universe. After a brief review on the current status of the research on cosmic reionization and 21-cm cosmology, I will report in this talk our recent progress in advancing our capability to model such an intrinsically nonlinear process more efficiently and more robustly, using numerical 3D radiative transfer simulations.