Year: 2013
Type: article
Abstract: Peculiar velocities, obtained from direct distance measurements, are data of choice to achieve constrained simulations of the Local Universe reliable down to a scale of a few megaparsec. Unlike redshift surveys, peculiar velocities are direct tracers of the underlying gravitational field as they trace both baryonic and dark matter. This paper presents the first attempt to use solely observational peculiar velocities to constrain cosmological simulations of the nearby Universe. In order to set up initial conditions, a Reverse Zel'dovich Approximation (RZA) is used to displace constraints from their positions at z = 0 to their precursors’ locations at higher redshifts. An additional new feature replaces original observed radial peculiar velocity vectors by their full 3D reconstructions provided by the Wiener–Filter (WF) estimator. Subsequently, the constrained realization (CR) of Gaussian fields technique is applied to build various realizations of the initial conditions. The WF/RZA/CR method is first tested on realistic mock catalogues built from a reference simulation similar to the Local Universe. These mocks include errors on peculiar velocities, on data point positions and a large continuous zone devoid of data in order to mimic galactic extinction. Large-scale structures are recovered with a typical accuracy of 5 h−1 Mpc in position, the best realizations reaching a 2–3 h−1 Mpc precision, the limit imposed by the RZA linear theory. Then, the method is applied to the first observational radial peculiar velocity catalogue of the project Cosmicflows. This paper is a proof of concept that the WF/RZA/CR method can be applied to observational peculiar velocities to successfully build constrained initial conditions.
Institutions: Lyon 1 Université, Centre National de la Recherche Scientifique, Leibniz Institute for Astrophysics Potsdam, Institut National de Physique Nucléaire et de Physique des Particules, Institute of Nuclear Physics of Lyon, Hebrew University of Jerusalem, University of Hawaiʻi at Mānoa, University of Hawaii System
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2049203344