The epoch before and during reionization is about to become accessible observationally through a combination of infrared and radio instruments and fine scale microwave background experiments. Understanding the nature of sources that reheated and reionized the intergalactic medium at the end of the dark ages is therefore crucial. This project will investigate the role of quasars in the high redshift Universe, combining ab initio cosmological simulations of quasar and galaxy formation and growth with high resolution radiative transfer to perform the first fully self consistent modeling of this epoch. The contribution of quasars through both thermal feedback and ionizing radiation, so far largely missing in theoretical predictions, is likely to dominate the early stages and substantially modify the large scale structure seen in neutral hydrogen. The simulations will reveal the complex interplay of pre-ionization by hard X-ray sources and the contribution of stellar sources, study the physical state of intergalactic gas, and make detailed physically motivated predictions of the number and character of radio sources.
These results have major implications for what is seen later, from quasars and supermassive black holes to the large-scale structure traced by dwarf galaxies. As the first observational studies of the dark ages are just on the horizon, being part of a new, emerging field will benefit the graduate student and undergraduates involved in the research. The results will be incorporated in an existing outreach program working with middle school students from underrepresented groups, and included in undergraduate coursework projects.
