New probes of cosmological initial conditions and dark matter properties

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Dr. Daniel Grin is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of Chicago. About one quarter of the Universe consists of an unknown constituent that astrophysicists have given the term "dark matter." Because this dark matter is all around us and has a profound effect upon the Universe, physicists seek to understand its nature and ultimately seek its true identity.The Fellow will conduct a theoretic study that addresses two unusual dark matter (DM) candidates: an extremely light axion (ELA) and a sterile neutrino. The ELA is motivated by string theory, the sterile neutrino by problems with Lambda Cold Dark Matter theory and by the non-zero neutrino mass. The Fellow will test these new DM candidates with observables, connect these ideas to the established CMB anisotropy experimental program and the spectral distortion frontier, and better connect atomic physics to the thermalization epoch. The Fellow will test homogeneity of the baryon fraction and improve understanding of non-Gaussian estimators with implications for early universe physics. This project will produce knowledge about the constituents of the universe and their fluctuations.The broader impacts of this project include a significant educational component. The Fellow will undertake a new outreach effort for senior citizens in underserved areas of Chicago, where opportunities for lifelong learning are few. The Fellow will create, manage, and present a new series of astronomy/cosmology classes in cooperation with senior centers of the Chicago Area Agency on Aging, reaching more than about 200 seniors a year. Classes will be free, taught by young scientists, and will appeal to many learning styles. The major objective of this work is to introduce modern research in astronomy/cosmology to underserved Chicago senior citizens.