Asher Grant recipient: ASRI member, Prof. Adi Nusser

19 Jan 2022

ASRI member, Prof. Adi Nusser from the Physics Department is one of this year's Asher Grant recipients, for his research: Constrained realizations of 2MRS density and peculiar velocity fields: growth rate and local flow.
Cosmology is witnessing exciting developments thanks to the rapid accumulation of observational data of the distribution and motions of galaxies in the Universe. The dominant form of matter, namely the dark matter, has not been detected in laboratory experiments, yet its presence is massively revealed through its gravitational effects. The nature of the dark matter, whether cold or hot, can directly be probed be observations of the large-scale density and velocity fields of galaxies. These observational are not only a valuable probe of dark matter but also of dark energy and indeed any deviations from Einstein’s of gravity on large cosmological scales. We are in the process of developing a novel framework for the efficient reconstruction of these fields from available redshift surveys as well as those from planned ground based telescopes and satellite missions. The framework aims at the maximal exploitation of the data in the Bayesian sense, in order to extract cosmological information on all observationally probed scales. To achieve this, we combine well studied theoretical results with modern statistical methods for a faithful estimation of statistical errors in the reconstructed fields and associated cosmological constraints.
As an illustration of the observations, the attached figure shows the reconstructed the density and peculiar velocity fields within 200 h −1 Mpc from the final release of the Two-Micron All-Sky Redshift Survey – the densest all-sky redshift survey to date. The figure is a slice of this reconstruction through the Supergalactic Plane.