Gravitational potential wells and the cosmic bulk flow

Abstract

The bulk flow is a volume average of the peculiar velocities and a useful probe of the mass distribution on large scales. The gravitational instability model views the bulk flow as a potential flow that obeys a Maxwellian Distribution. We use two N-body simulations, the LasDamas Carmen and the Horizon Run, to calculate the bulk flows of various sized volumes in the simulation boxes. Once we have the bulk flow velocities as a function of scale, we investigate the mass and gravitational potential distribution around the volume. We found that matter densities can be asymmetrical and difficult to detect in real surveys, however, the gravitational potential and its gradient may provide better tools to investigate the underlying matter distribution. This study shows that bulk flows are indeed potential flows and thus provides information on the flow sources. We also show that bulk flow magnitudes follow a Maxwellian distribution on scales $>10h^{-1}$Mpc.

16 pages, 8 figures

References in corpus (8)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The 6dF Galaxy Survey: Bulk Flows on $50-70h^{-1}$ Mpc scales
• Coming of Age in the Dark Sector: How Dark Matter Haloes grow their Gravitational Potential Wells
• Deriving accurate peculiar velocities (even at high redshift)
• An Unbiased Estimator of Peculiar Velocity with Gaussian Distributed Errors for Precision Cosmology
• 2MTF IV. A bulk flow measurement of the local Universe
• Large-scale Cosmic Flows from Cosmicflows-2 Catalog
• An Inconsistency in standard Maximum Likelihood Estimation of Bulk Flows

Cited by in corpus (1)

• Peculiar Velocity Estimation from Kinetic SZ Effect using Deep Neural Networks