Alexander Eggemeier - Cosmological constraints from two- and three-point galaxy clustering

#PizzaSeminar

Title: "Cosmological constraints from two- and three-point galaxy clustering"
Speaker: Alexander Eggemeier, Argelander-Institut für Astronomie (Bonn University)

Galaxy surveys are instrumental in measuring the Universe’s geometry and the growth of cosmic structures, providing constraints that complement and are competitive with those from the cosmic microwave background and Type Ia supernovae. Despite this, current constraints from large-scale structures primarily rely on statistics describing the clustering of galaxy pairs, neglecting the rich information embedded in the more complex patterns of the cosmic web. In this presentation, I will begin by summarizing the conventional techniques for analysing galaxy clustering, highlighting the advantages of incorporating three-point information (galaxy triplets). The discussion will then focus on the challenge of accurately predicting redshift-space distortions, which are induced by the peculiar velocities of galaxies. This issue has so far limited the benefits from combined two- and three-point statistics analyses, a concern that grows as statistical uncertainties decrease with upcoming data from the Dark Energy Spectroscopic Instrument (DESI) and the Euclid telescope. I will contrast the approach currently employed in standard effective field theory methods with a model that incorporates a deeper understanding of the peculiar velocity distributions. I will demonstrate that this not only leads to a more accurate description of the data, but also significantly tightens cosmological parameter constraints, largely due to enhancements unlocked by three-point statistics.