Coherence of largescale velocities.
Abstract
The radial components of the galaxy peculiar velocities are related to primordial density fluctuations via a tensor window function. For a given shell of galaxies the radial velocity as a function of direction can be expanded in multipoles, the l = 1 term corresponding to the bulk motion, the l = 2 to a quadrupole anisotropy of the velocity field. The l = 0 "breathing mode", even if present, is unobservable. The author derives the distribution of the bulk velocity of such a shell and compares it to the results obtained with the usual scalar window function. The estimated velocity and the statistical scatters are significantly affected by sampling anisotropies in the galaxy selection function. The author also estimates the rms values of the various multipole moments of the velocity field and generates some MonteCarlo realizations assuming the cold dark matter spectrum.
 Publication:

LargeScale Motions in the Universe: A Vatican study Week
 Pub Date:
 1988
 Bibcode:
 1988lsmu.book..323S
 Keywords:

 Elliptical Galaxies;
 Hubble Constant;
 Radial Velocity;
 Velocity Distribution;
 Angular Velocity;
 Center Of Mass;
 Coherence;
 Dark Matter;
 Monte Carlo Method;
 Astrophysics;
 Clusters of Galaxies: Velocity Fields;
 Superclusters: Velocity Fields