Probing Structure Growth with Constrained Realizations of the Local Universe

Abstract: The distribution of structures in the local Universe and their flows provide a valuable probe of cosmic structure formation. One way to access this information is to reconstruct the density and velocity fields of these structures, using the distribution of observable galaxies. However, since observations of a finite set of galaxies are contaminated by shot noise, there is in fact an ensemble of possible reconstructions that are all compatible with the observations within the expected noise. In this talk, I present a method to generate such an ensemble of so-called constrained realizations based on the final release of the 2MASS Redshift Survey (2MRS), the densest all-sky redshift survey to date. This approach combines a noise-suppressing minimum-variance estimator with a generator of random mock galaxy catalogues. After explaining the method, I show the resulting reconstructions and demonstrate how we can combine them with the Cosmicflows-3 catalogue of galaxy distances to constrain the cosmic growth rate as well as the motion of the Local Group with respect to the CMB. I finish with an outlook on applying this method to the future all-sky spectral redshift survey SPHEREx.

Video of Talk: https://www.youtube.com/watch?v=eFCOAcHZzQY

cosmology and nongalactic astrophysicsgeneral relativity and quantum cosmology

Audience: advanced learners

( slides | video )

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CosmoConβ - Cosmology from Home

Series comments: Cosmology from Home is an online cosmology conference. One of its features are pre-recorded talks, publicly available at its YouTube channel.

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