Probing the Epoch of Reionization with 21cm and metal absorption

Abstract

The epoch over which the first luminous sources ionized the neutral hydrogen in the intergalactic medium (IGM) and ended the cosmic dark ages is called as the Epoch of Reionization (EoR). Answering the questions : how and when did reionization occur are key goals of modern day observational and theoretical cosmology. Measurements of the thompson scattering optical depths from observations of the cosmic microwave background and detection and studies of the Gunn-Peterson troughs in the spectra of high redshift quasars have established that reionization occured by z≈ 6. The epoch of reionization has witnessed the birth of the first stars, the initial enrichment of the cosmic gas with metals synthesized in the stars, and the formation of galaxies, including the progenitors of more massive galaxies like the one we line in, the Milky Way and thus is a key epoch in the history of the universe. Imaging the Universe during its infancy remains one of the exciting challenges facing modern cosmology. Determining when and how the first luminous sources reionized the intergalactic medium (IGM) will shed light on both the nature of the first objects and the history of baryonic matter in the universe. Quasar absorption lines play a unique role by probing the properties of diffuse gas on a variety of scales ranging from galactic to intergalactic. Using a suite of radiation-hydrodynamical simulations of galaxy formation and the epoch of reionization called the Aurora simulations, I aim to study correlations between 21 cm and metal absorption a way to probe the properties of the IGM during the EoR.