The Coherence Length of the Peculiar Velocity Field in the Universe and the Large-Scale Galaxy Correlation Data
Abstract
Large-scale peculiar flows in the universe carry important information about the nature of the underlying density fluctuations on linear scales where the power spectrum has preserved its original shape. The coherence length of the velocity field constrains the power spectrum, and if the latter is known, the velocity amplitude should allow one to determine the density parameter {OMEGA}. On linear scales the velocity correlation function, v(r), is uniquely specified by the matter two-point correlation function, ξ(r). Information on the latter comes from the recently completed APM survey which gives accurate measurements of the projected angular correlation function, w({THETA}), on very large scales. w({THETA}) is uniquely related to ξ(r) via the Limber equation and, consequently, uniquely specifies v(r). We develop a method to obtain the true rms peculiar flow in the universe on scales up to 100-120 h^-1^ Mpc using the APM data as an input assuming only that peculiar motions have been caused by peculiar gravity. The comparison to the local (Great Attractor) flow should then give clear information on {OMEGA} and the local bias parameter, b. We find that the observed peculiar flows in the Great Attractor region are in better agreement with the open ({OMEGA} = 0.1) universe in which light traces mass (b = 1) than with a flat ({OMEGA} = 1) universe unless the bias parameter is unrealistically large (b >= 4).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1992
- DOI:
- 10.1086/186287
- Bibcode:
- 1992ApJ...386L..37K
- Keywords:
-
- Angular Correlation;
- Computational Astrophysics;
- Galactic Clusters;
- Universe;
- Velocity Distribution;
- Galactic Evolution;
- Gravitational Effects;
- Power Spectra;
- Astrophysics;
- GALAXIES: CLUSTERING;
- GALAXIES: FORMATION;
- GRAVITATION;
- COSMOLOGY: LARGE-SCALE STRUCTURE OF UNIVERSE