Constraining Cosmic Baryons and Dark Matter with the Lyman-alpha Forest

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• Brant Robertson (UCSC)
• Friday 02 December 2022, 11:30-12:30
• in person & via zoom .

If you have a question about this talk, please contact Sandro Tacchella.

The filamentary network of intergalactic medium (IGM) gas that gives origin to the “Lyman-alpha forest” encodes information on the physics of structure formation and the early thermodynamics of diffuse baryonic material. I will present results from a massive suite of more than 1080 high-resolution cosmological hydrodynamical simulations run with the Graphics Processing Unit-accelerated code Cholla to study the IGM at high spatial resolution. By varying the amplitude and timing of the photoheating and photoionizing background produced by star-forming galaxies and active galactic nuclei, we can match the observed hydrogen Lyman-alpha forest power spectra and helium Lyman-alpha forest opacity. The available data tightly constrain the photoionization and photoheating history of the IGM , and allow us to infer its thermal history. We then present a new analysis varying the dark matter particle mass to study the consistency between possible free-streaming suppression of the small-scale matter power spectrum and the Lyman-alpha forest, allowing us to constrain cosmological physics from the Lyman-alpha forest while robustly accounting for thermal structure of the IGM .

This talk is part of the Galaxies Discussion Group series.

This talk is included in these lists:

• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Galaxies Discussion Group
• Institute of Astronomy Talk Lists
• Kavli Institute for Cosmology Talk Lists
• in person & via zoom

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