Astro Lunch: Johannes Lange (Stanford-Santa Cruz)

September 24, 2021 - 12:00pm


Probing Cosmic Structure Growth with Simulation-Based Full-Scale Modeling

The canonical picture of cosmology, the Lambda Cold Dark Matter (LCDM) model, has been remarkably successful in explaining a large variety of different observations. However, in recent years, apparent tensions in this standard model have started to appear, sparking interest in alternative cosmological models. Cosmic structure growth as probed by large-scale structure (LSS) galaxy surveys is one of the most sensitive probes of dark energy and physics beyond LCDM. I will summarize recent results from LSS surveys analyzing weak gravitational lensing, focussing on the possibility of a cosmological growth-of-structure tension. Afterwards, I will present recent efforts to maximize the information content we can extract from LSS surveys through simulation-based full-scale cosmological studies. I will discuss how the "lensing is low" problem can illuminate our understanding of cosmic structure growth as well as galaxy formation physics. Afterwards, I will present a full-scale cosmology study of the redshift-space galaxy correlation function. Such an analysis yields some of the tightest constraints on the cosmic growth rate of the Universe to date. Finally, I will discuss ongoing work in the C3 group to study cosmic structure growth with the Dark Energy Spectroscopic Instrument (DESI) survey.

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