Scheme: University Research Fellowship
Organisation: University of Nottingham
Dates: Oct 2012-Sep 2017
Summary: What are the origins of the Universe? How and when did the stars and galaxies we see in the night sky form? These are some of the questions that have fascinated humans since the dawn of observational astronomy. In the last few years, powerful ground and space-based telescopes have finally enabled astronomers to obtain tantalising glimpses of the time when these first galaxies formed, less than a billion years after the Big Bang when the Universe was only a fraction of its current age. Despite this progress, however, there is still much to be learned about this important epoch.
One of the most important astrophysical techniques which can be used to help shed further light on the physical conditions under which the first stars and galaxies formed is spectroscopy; the study of visible and (at longer wavelengths) infrared light, dispersed into its constituent colours to form a spectrum. The spectra of the most distant luminous objects contain a wealth of information on the physical and chemical state of the early Universe. For this reason, a class of objects of particular interest to astronomers are quasars. These extraordinarily bright, distant objects - thought to be due to super-massive black-holes swallowing matter in the early Universe - act like cosmic beacons, highlighting the intergalactic gas lying along the line-of-sight from them towards us.
By studying the imprint of this “intergalactic medium” of ancient gas in quasar spectra, astronomers can study the physical conditions in the early Universe when the first stars and galaxies were forming. My research uses detailed supercomputer simulations of this intergalactic gas to interpret these spectroscopic observational signatures, enabling us to learn about the formation and evolution of the first stars and galaxies during the cosmic dawn. By doing so, we are able to explore physics using the largest, most diverse laboratory at our disposal - the entire Universe.