Cosmology at high redshift with spectroscopic surveys and the Lyman-𝛼 forest

by Andrei Cuceu

Friday 26 Jan 2024, 11:00 → 12:00 US/Eastern

Small Seminar Room

The Lyman-alpha (Lya) forest is currently one of the most powerful probes of large-scale structure at high redshift (2 < z < 4). This is made possible by large spectroscopic surveys that measure hundreds of thousands of quasar spectra. Over the last decade, the Lya forest has been successfully used to measure the high redshift expansion rate, and place tight constraints on the nature of dark energy. The fourth stage of dark energy experiments is spearheaded by the Dark Energy Spectroscopic Instrument (DESI), which began survey operations in 2021, and within less than a year collected the largest ever spectroscopic dataset. In this talk, I will show how DESI is using the Lya forest to comprehensively map the cosmic expansion history between redshifts 2 and 4, and present the current status of our analysis of DESI Year 1 data. I will also discuss my recent work on extracting more cosmological information from the Lya forest, which has already led to a factor of two improvement in expansion rate constraints at high redshift. Finally, I will present the exciting opportunities that can be unlocked by making full use of both Lya forest and galaxy datasets in the context of the next generation of spectroscopic surveys.

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