相关论文: The Velocity Field Around Groups of Galaxies
I summarize both observational and theoretical developments in the last few years in measuring and understanding the large-scale velocity field of galaxies, with special attention to the bulk flow, or average peculiar velocity, within…
The properties of the velocity field in the local volume (cz < 550 km/s) have been difficult to constrain due to a lack of a consistent set of galaxy distances. The sparse observations available to date suggest a remarkably quiet flow, with…
Cepheid distances of local galaxies (<7 Mpc) are used to study the very nearby velocity field, as pioneered by Sandage (Sandage 1986) who also pointed out its remarkable properties: linearity and quietness. The new data show that the…
The systemic velocity or redshift of galaxies is a convenient tool to calculate their distances in the absence of primary methods, but the uncertainties on these flow distances may be substantial due to galaxy peculiar motions. Here, we…
The origins of recently reported anisotropy of the local velocity field of nearby galaxies (velocities < 500 km/s corresponding to the distance less than 8 Mpc) are studied. The exact solution of the Newtonian equation for the expanding…
Analysis of the peculiar velocities of galaxies should take account of the uncertainties in both redshifts and distances. We show how this can be done by a numerical application of the action principle. The method is applied to an improved…
We examine the peculiar velocity distribution function of galaxies in cosmological many-body gravitational clustering. Our statistical mechanical approach derives a previous basic assumption and generalizes earlier results to galaxies with…
By correcting the redshift--dependent distances for peculiar motions through a number of peculiar velocity field models, we recover the true distances of a wide, all-sky sample of nearby galaxies (~ 6400 galaxies with velocities cz<5500…
To reveal small galaxy groups in the Local Supercluster, a new approach is suggested which allows for individual properties of galaxies. The criterion is based on the assumption of closed motions of companions around the dominating group…
Galaxy cluster peculiar velocities can be inferred from high-sensitivity, high-resolution multiple-frequency observations in the 30 to 400 GHz range. While galaxy cluster counts and power spectra are sensitive to the growth factor, peculiar…
The existence of critical points for the peculiar velocity field is a natural feature of the correlated vector field. These points appear at the junctions of velocity domains with different orientations of their averaged velocity vectors.…
We present a new method for recovering the underlying velocity field from an observed distribution of galaxies in redshift space. The method is based on a kinematic Zel'dovich relation between the velocity and density fields in redshift…
A new method is proposed for directly measuring the expansion rate of the universe through very precise measurement of the fluence of extremely stable sources. The method is based on the definition of the luminosity distance and its change…
The local Hubble flow provides a valuable probe of the transition between cosmic expansion and nonlinear gravitational dynamics. On large scales, galaxies follow the linear Hubble law, but within group- and cluster-sized environments,…
This work analyses the properties of groups of galaxies in the surroundings of clusters. On the basis of a very large public Virgo Consortium Simulation, we identified systems of galaxies in a wide range of masses. Systems with masses…
We analyze the internal velocity dispersions of a sample of 172 nearby galaxy clusters (z < 0.15), each of which has at least 30 available galaxy redshifts, and spans a large richness range. Cluster membership selection is based on…
We investigate the dynamics of an homogenous distribution of galaxies moving under the cosmological expansion through Euler-Poisson equations system. The solutions are interpreted with the aim of understanding the cosmic velocity fields in…
Two dimensional velocity fields have been an important tool for nearly 30 years and are instrumental in understanding galactic mass distributions and deviations from an ideal galactic disk. Recently a number of new instruments have started…
We analyze the velocity field of peripheral members of the Local Group. The Hubble flow at distances from 400 to 1400~kpc, formed by 7 of 11 nearby galaxies, is characterized by an extremely small line-of-sight velocity dispersion of 15…
Reviews observational situation in the measurement of peculiar velocities in the local universe. Emphasis is placed on such topics as: Do spirals and ellipticals yield the same peculiar velocity field? What is the cluster velocity…