Unlocking the unexplored epoch of cosmic dawn with radio telescopes and advanced analysis techniques

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Cosmologists have now observed both the Universe today as well as its primordial conditions. However, the crucial epoch of Cosmic Dawn---the period when the first stars and galaxies illuminated our Universe---remains unobserved. As a result, we remain ignorant of how modern astronomical structures came to be. For instance, what was the nature of the first galaxies? Were they primarily large galaxies or a broader population of smaller ones? What role, if any, did the particle physics of neutrinos and (possibly) annihilating dark matter play in this era?******My research program unlocks the era of Cosmic Dawn to direct observations. We do so via 21cm tomography, where faint radio emission from neutral hydrogen atoms are used to make large scale maps of our Universe. These maps then provide a direct picture of how first-generation galaxies illuminated, ionized, and permanently altered our cosmos.******This Discovery Grant research program targets the opportunity to turn the long-term vision of 21cm cosmology into observational reality using data from the Hydrogen Epoch of Reionization Array (HERA), a novel low-frequency radio interferometer. The short-term activities to be undertaken in this grant period are to:******(1) Deliver a software pipeline for reducing raw HERA data into the first direct images of Cosmic Dawn and statistical quantities such as a power spectrum measurement.******(2) Analyze and interpret the resulting power spectra to determine the properties of first-generation galaxies, such as their typical mass, their clustering, and their emission properties. Interface with other cosmological probes (such as the Cosmic Microwave Background) to produce sharpened constraints on fundamental parameters such as the neutrino mass.******(3) Incorporate machine learning techniques to develop next-generation analysis techniques for 21cm cosmology. Move beyond power spectrum analyses by applying image-recognition techniques to images of Cosmic Dawn. Use machine-learning to aid in the design and optimization of next-generation telescopes.******This grant will provide training for undergraduates, graduate students, and postdoctoral fellows in the emerging field of 21cm cosmology. Their expertise and the analysis tools that are developed as part of this proposal will be made available to the large Canadian presence in 21cm cosmology, including CHIME, the Murchison Widefield Array, and the Square Kilometre Array.