| New Probes of Astrophysics and Cosmology with 21cm cosmology |
| Adrian Liu, McGill University |
| Event Type: Astro Seminar |
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| Time: 2:00 PM - 3:15 PM |
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| Location: 726 Broadway, 940, CCPP Seminar |
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| Abstract: In recent years, considerable progress has been made in using the 21cm line of neutral hydrogen to survey the high-redshift universe. First, I will summarize new upper limits—to appear on the arXiv later this month—from the Hydrogen Epoch of Reionization Array (HERA). These limits are now strong enough that they rule out certain theory models of Cosmic Dawn (the era of first-generation stars and galaxies). Looking beyond our current limits, I will propose an idea for combining machine learning with 21cm observations to look beyond the messy astrophysics of Cosmic Dawn to constrain fundamental cosmological parameters. If time permits, I will also discuss some in-progress work regarding how 21cm cosmology can be complementary to other probes of Cosmic Dawn. In particular, I may discuss how UV luminosity functions may be a new, more constraining way to probe the presence (or not) of cosmic strings. Additionally, I may discuss some recent efforts to use symbolic regression as a tool for understanding the relationship between the wide variety of models of reionization in the literature. This enables critical evaluations of theory systematics in these models and how such systematics may propagate to joint CMB-21cm constraints. |