Optical galaxies within 8000 km s-1. III. Inhomogeneous Malmquist bias corrections and the Great Attractor.
Malmquist bias corrections to galaxy distances depend sensitively in the underlying density field from which the distance-indicator population is assumed to have been drawn. In most previous studies of large-scale streaming motions, the density field has been assumed to be homogeneous. In this paper, inhomogeneous Malmquist bias corrections are calculated using the density field of optical galaxies within 8000 km s-1. For E and S0 galaxies in the Great Attractor region, the strong outward streaming in the foreground of the Great Attractor is not significantly affected by these new corrections. Some evidence of backside infall into the Great Attractor had previously been claimed by Dressler and Faber on the basis of the homogeneously corrected Dn-σ peculiar velocities. It is found here that approximately 500 km s-1 of their backside infall is due to inappropriate homogeneous Malmquist bias corrections. The best-fitting flow model to the inhomogeneously corrected Dn-σ peculiar velocities in the CMB frame is a Great Attractor centred infall of 266±51 km s-1 at the Local Group plus a bulk dipole motion of 212±82 km s-1 towards l = 316°, b = 10°.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 1994
- Galaxies: Distance Indicators;
- Galaxies: Redshifts;
- Galaxies: Great Attractor;
- Universe: Large-Scale Structure MNRAS Keywords: methods: statistical - galaxies: distances and redshifts - cosmology: observations - large-scale structure of Universe