The peculiar velocity field in flattened superclusters.
Abstract
The linear growth rate of small transverse perturbations in a selfgravitating, collisionless gas that is undergoing a onedimensional collapse is strongly influenced by the nonlinear flow of the background. In the collapse plane, smaller Hubble flow deviations and infall velocities are obtained than in the simple linear theory. Application of this theory to the kinematics of galaxies in a flat supercluster shows that the usual linear approximation may seriously underestimate Omega, the density parameter of the universe, if there is a strong deviation from spherical symmetry. Furthermore, dissipative separation of baryonic matter from collisionless dark material (such as hypothesized massive neutrinos) enhances this effect, leading to apparent Omega values of 0.20.3 for a wide range of separation parameters in an Einsteinde Sitter (Omega = 1) model.
 Publication:

The Astrophysical Journal
 Pub Date:
 January 1983
 DOI:
 10.1086/183939
 Bibcode:
 1983ApJ...264L..31S
 Keywords:

 Cosmology;
 Galactic Clusters;
 Gas Flow;
 Velocity Distribution;
 Virgo Galactic Cluster;
 Baryons;
 Fourier Transformation;
 Kinematic Equations;
 Space Density;
 Astrophysics