相关论文: Galaxies: Lighthouses in the Shoals of Dark Halos

The smallest dark matter halos are formed first in the early universe. According to recent studies, the central density cusp is much steeper in these halos than in larger halos and scales as $\rho \propto r^{-(1.5-1.3)}$. We present results…

We use a dedicated 0.7-m telescope to image the halos of 119 galaxies in the Local Volume to $\mu_r \sim 28-30$ mag/arcsec$^2$. The sample is primarily from the 2MASS Large Galaxy Atlas and extended to include nearby dwarf galaxies and more…

We have used dedicated 0.7m telescopes in California and Israel to image the halos of ~200 galaxies in the Local Volume to 29 mag/sq arcsec, the sample mainly drawn from the 2MASS Large Galaxy Atlas (LGA). We supplement the LGA sample with…

We use the clustering results obtained by Madgwick et al. (2003) for a sample of 96,791 2dF galaxies with redshift 0.01 \lt z \lt 0.15 to study the distribution of late-type and early-type galaxies within dark matter haloes of different…

Star clusters have hierarchical patterns in space and time, suggesting formation processes in the densest regions of a turbulent interstellar medium. Clusters also have hierarchical substructure when they are young, which makes them all…

During hierarchical clustering, smaller masses generally collapse earlier than larger masses and so are denser on the average. The core of a small mass halo could be dense enough to resist disruption and survive undigested, when it is…

Stellar halos are the only major stellar component of disk galaxies that lack systematic observational characterization, yet they encode critical information about galaxy merger histories. We present the first systematic census of stellar…

In a serie of three papers, the dynamical interplay between environments and dark matter haloes is investigated, while focussing on the dynamical flows through their virial sphere. Our method relies on both cosmological simulations, to…

The late infall of cold dark matter onto an isolated galaxy, such as our own, produces streams and caustics in its halo. The outer caustics are topological spheres whereas the inner caustics are rings. The self-similar model of galactic…

We study galaxy clustering using halo models, where gravitational clustering is described in terms of dark matter halos. At small scales, clustering statistics are dominated by halo density profiles, whereas at large scales, correlations…

High-resolution LCDM cosmological N-body simulations are used to study the properties of galaxy-size dark halos in different environments (cluster, void, and "field"). Halos in clusters and their surroundings have a median spin parameter…

The question we address in this paper is the determination of the correlation properties of the dark matter halos appearing in cosmic density fields once they underwent a strongly nonlinear evolution induced by gravitational dynamics.…

The structure of dark matter halos as predicted from cosmological models is discussed and compared with observed rotation curves of dark matter-dominated dwarf galaxies. The theoretical models predict that dark matter halos represent a…

We examine ultraviolet halos around a sample of highly inclined galaxies within 25 Mpc to measure their morphology and luminosity. Despite contamination from galactic light scattered into the wings of the point-spread function, we find that…

High-resolution N--body simulations show a remarkable similarity in the structure of dark matter halos formed through dissipationless hierarchical clustering. Independent of halo mass, power spectrum, and cosmological parameters, the…

We use N-body simulations to examine whether a characteristic turnaround radius, as predicted from the spherical collapse model in a $\rm {\Lambda CDM}$ Universe, can be meaningfully identified for galaxy clusters, in the presence of full…

Caustics are formally singular structures, with infinite density, that form in collisionless media. The non-negligible velocity dispersion of dark matter particles renders their density finite. We evaluate the maximum density of the…

Using the Hubble Space Telescope, we have resolved individual red-giant branch stars in the halos of eight nearby spiral galaxies. The fields lie at projected distances between 2 and 13 kpc along the galaxies' minor axes. The data set…

We use very high resolution cosmological zoom simulations to follow the early evolution of twelve first-generation haloes formed from gaussian initial conditions with scale-free power spectra truncated on small scales by a gaussian in…

Identification of first and second turnaround radii in groups of galaxies provide interesting scaling relations and may constrain cosmological parameters.