Astro 2020 Science White Paper: Fundamental Cosmology in the Dark Ages with 21-cm Line Fluctuations
Authors: Steven Furlanetto, Judd D. Bowman, Jordan Mirocha, Jonathan C. Pober, Jack Burns, Chris L. Carilli, Julian Munoz, James Aguirre, Yacine Ali-Haimoud, Marcelo Alvarez, Adam Beardsley, George Becker, Patrick Breysse, Volker Bromm, Philip Bull, Tzu-Ching Chang, Xuelei Chen, Hsin Chiang, Joanne Cohn, Frederick Davies, David DeBoer, Joshua Dillon, Olivier Doré, Cora Dvorkin, Anastasia Fialkov, Bryna Hazelton, Daniel Jacobs, Kirit Karkare, Saul Kohn, Leon Koopmans, Ely Kovetz, Paul La Plante, Adam Lidz, Adrian Liu, Yin-Zhe Ma, Yi Mao, Kiyoshi Masui, Andrew Mesinger, Steven Murray, Aaron Parsons, Benjamin Saliwanchik, Jonathan Sievers, Nithyanandan Thyagarajan, Hy Trac, Eli Visbal, Matias Zaldarriaga
Abstract: The Dark Ages are the period between the last scattering of the cosmic microwave background and the appearance of the first luminous sources, spanning approximately 1100 < z < 30. The only known way to measure fluctuations in this era is through the 21-cm line of neutral hydrogen. Such observations have enormous potential for cosmology, because they span a large volume while the fluctuations remain linear even on small scales. Observations of 21-cm fluctuations during this era can therefore constrain fundamental aspects of our Universe, including inflation and any exotic physics of dark matter. While the observational challenges to these low-frequency 21-cm observations are enormous, especially from the terrestrial environment, they represent an important goal for cosmology.