Theoretical implications of cosmological dipoles.
Abstract
We have compared the dipole a anisotropy of the IRAS and optical sky and the peculiar velocity bulkflow solutions with the cold dark matter (CDM) predictions using linear theory. We have obtained maximum likelihood estimates of the normalization parameter, σ_{rho}_, defined as the rms mass fluctuation in 8 Mpc h^1^ spheres, and the bias parameter, b, defined as the ratio of the fluctuation in galaxy counts to the mass fluctuation. For the IRAS dipoles and the velocity data, the parameters (bσ_{rho}_~1.1, σ_{rho}_~0.7) agree well with those derived from smaller scale phenomena, and the χ^2^ statistics are quite acceptable. We find some indications for more power at large scales from the optical data (bσ_{rho}_~1.9). The data are also compatible with the Isocurvature Baryon model. We have developed and applied an improved version of Gott's test using the correlations between a number of angular dipoles and bulk flow solutions. We obtain a value for the bias parameter for IRAS galaxies of b~1.6 (or '{OMEGA}_0_'~0.5 for an unbiased model) and for optical galaxies of b~2.0 (or '{OMEGA}_0_'~0.3). Following recent modelling of the peculiar velocity field, we have also made simple models with one or more `Great Attractorlike' spherical perturbations.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 March 1989
 DOI:
 10.1093/mnras/237.1.129
 Bibcode:
 1989MNRAS.237..129K
 Keywords:

 Cosmology;
 Dark Matter;
 Dipoles;
 Infrared Astronomy Satellite;
 Maximum Likelihood Estimates;
 Astronomical Models;
 Mass Distribution;
 Velocity Distribution;
 Astrophysics