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arXiv · 2106.11979

Probing Compensated Isocurvature with the 21-cm Signal during Cosmic Dawn

Selim C. Hotinli·Thomas Binnie·Julian B. Muñoz·Bikash R. Dinda·Marc Kamionkowski
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Abstract

Upcoming measurements of the 21-cm line of neutral hydrogen will open a new observational window into the early stages of structure growth, providing a unique opportunity for probing large-scale cosmological signatures using the small-scale signals from the first stars. In this paper we evaluate the detection significance of compensated isocurvature perturbations (CIPs) from observations of the 21-cm hydrogen-line during the cosmic-dawn era. CIPs are modulations of the relative baryon and dark-matter density that leave the total matter density unchanged. We find that, under different assumptions for feedback and foregrounds, the ongoing HERA and upcoming SKA1-low experiments will provide constraints on uncorrelated CIPs at the level of $\sigma(A_{\rm CIP})= 10^{-3}-10^{-4}$, comparable to the sensitivity of upcoming CMB experiments, and potentially exceeding the constraints from cosmic-variance limited BAO surveys.

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Selim C. Hotinli, Thomas Binnie, Julian B. Muñoz, Bikash R. Dinda, Marc Kamionkowski. 2021-06-22. Probing Compensated Isocurvature with the 21-cm Signal during Cosmic Dawn. https://doi.org/10.1103/physrevd.104.063536

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