Optical galaxies within Formula - IV. The peculiar velocity field

The Density and Peculiar Velocity Elds of Nearby Galaxies

We review the quantitative science that can be and has been done with redshift and peculiar velocity surveys of galaxies in the nearby universe. After a brief background setting the cosmological context for this work, the rst part of this review focuses on redshift surveys. The practical issues of how redshift surveys are carried out, and how one turns a distribution of galaxies into a smoothed...

Streaming motions of galaxy clusters within 12000 km s − 1 — V . The peculiar velocity field

We analyze in detail the peculiar velocity field traced by 56 clusters within 120 hMpc in the “Streaming Motions of Abell Clusters” (SMAC) sample. The bulk flow of the SMAC sample is 687 ± 203 km s, toward l = 260◦ ± 13, b = 0◦ ± 11. We discuss possible systematic errors and show that no systematic effect is larger than half of the random error. The flow does not drop off significantly with dep...

Peculiar Galaxies

Hierarchical Object Formation in the Peculiar Velocity Field

Using the initial peculiar-velocity field, we analytically study the hierarchical formation of gravitationally bound objects. The field is smoothed over a scale that corresponds to the mass of a given class of objects. Through the Zel’dovich approximation, the smoothed field determines how the objects cluster together to form a new class of more massive objects. The standard cosmological parame...

The peculiar velocity field in a quintessence model

We investigate the evolution of matter density perturbations and some properties of the peculiar velocity field for a special class of exponential potentials in a scalar field model for quintessence, for which a general exact solution is known. The data from the 2-degree Field Galaxy Redshift Survey (2dFGRS) suggest a value of the today pressureless matter density ΩM0 = 0.18±0.05.