Journal Article

Testing the minimum variance method for estimating large-scale velocity moments

Shankar Agarwal, Hume A. Feldman and Richard Watkins

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 424, issue 4, pages 2667-2675
Published in print August 2012 | ISSN: 0035-8711
Published online August 2012 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2012.21345.x
Testing the minimum variance method for estimating large-scale velocity moments

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Abstract

The estimation and analysis of large-scale bulk flow moments of peculiar velocity surveys is complicated by non-spherical survey geometry, the non-uniform sampling of the matter velocity field by the survey objects and the typically large measurement errors of the measured line-of-sight velocities. Previously, we have developed an optimal ‘;minimum variance’ (MV) weighting scheme for using peculiar velocity data to estimate bulk flow moments for idealized, dense and isotropic surveys with Gaussian radial distributions, that avoids many of these complications. These moments are designed to be easy to interpret and are comparable between surveys. In this paper, we test the robustness of our MV estimators using numerical simulations. Using MV weights, we estimate the bulk flow moments for various mock catalogues extracted from the LasDamas and the Horizon Run numerical simulations and compare these estimates to the moments calculated directly from the simulation boxes. We show that the MV estimators are unbiased and negligibly affected by non-linear flows.

Keywords: galaxies: kinematics and dynamics; galaxies: statistics; cosmology: observations; cosmology: theory; distance scale; large-scale structure of Universe

Journal Article.  6568 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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