Ph.D. Thesis Defenses
Past Ph.D. Thesis Defenses

Challenges in theoretical modeling of cosmic reionization
March 29, 2016 | ERC 576 | 1:05 PM
Alexander Kaurov

Ph.D. Committee members: Andrey Kravtsov, Hsiao-Wen Chen, Wayne Hu

"Dr. Alexander Kaurov's work on studying cosmic reionization - the process of ionization of the bulk of cosmic gas by ultraviolet radiation from the first stars and quasars - was instrumental in combining diverse theoretical concepts into a single, unified paradigm that connects directly with modern state-of-the-art numerical simulations. This breakthrough will have numerous practical applications for the analysis and interpretation of the forthcoming observational data from the future James Webb Space Telescope, Giant Magellan Telescope, and radio observations of the epoch when the first galaxies lit up."
- Nickolay Y. Gnedin, Ph.D. advisor

Thesis Abstract: As the sensitivity and precision of modern instruments increases, the observations start to approach two digit redshifts, which is a mid-reionization epoch. In the upcoming decade we expect to have many of highly diverse observations of the epoch of reionization. Those observations will include: 21cm global signal and tomography experiments, improved CMB polarization measurements, the properties of individual galaxies including Ly╬▒ emitters, and the ionization state of the IGM through observations of the spectra of high-z quasars.

Even though for each of these observations theoretical models are already developed; there is no unified theoretical framework to analyze them altogether in a self-consistent way, i.e. to perform a full Bayesian analysis of all available observations. Therefore, I would like to discuss why it is still an unsolved problem and how it can be approached. In particular, I will talk about our latest developments in numerical simulations of cosmic reionization with full radiation transfer, and their interplay with approximate semi-analytical methods. Most importantly, I will review possibilities for the parameter spaces used in reionization models. In addition, I will present our recent results on more exotic reionization scenarios that include dark matter annihilation.