From cosmic dawn to the present: Searching for the first stars and for direct evidence for dark matter

This project proposes to significantly advance, and tie together, two of the most fundamental areas in cosmology: our cosmic origins and the make-up of the universe. Since the universe was filled with hydrogen atoms at early times, the most promising method for observing the epoch of the first stars is to measure the radio emission from hydrogen. I propose to lay out the theoretical background needed to ensure a successful detection of cosmic dawn with radio telescopes, including exploring the full range of possible signals and methods to interpret them. Meanwhile, we have recently proposed a new way to confirm the existence of the dark matter that is thought to fill the universe. An expected difference in the distribution of ordinary gas and dark matter, which results from early cosmic history, should be detectable in the distribution of galaxies today. Our recent first attempt to detect this did not quite succeed, so we plan to improve on this by better modeling and using newly-available data. Most interestingly, the above two topics are related; the astronomy community is unaware of this fact, which we plan to point out and develop. Indeed, the radio signal from the earliest galaxies should include this signature of dark matter, and measuring this would help confirm both the existence of dark matter and the claimed detection of the radio signal from early cosmic times. In general, we anticipate that our project will yield significant results that will be published in leading scientific journals and will draw the attention of the scientific community as well as the general public.