相关论文: Flattening of dark matter cusps during mergers: mo…
We propose a model for how the buildup of dark halos by merging satellites produces a characteristic inner cusp, of a density profile \rho \prop r^-a with a -> a_as > 1, as seen in cosmological N-body simulations of hierarchical clustering…
We use high resolution simulations of isolated dwarf galaxies to study the physics of dark matter cusp-core transformations at the edge of galaxy formation: M200 = 10^7 - 10^9 Msun. We work at a resolution (~4 pc minimum cell size; ~250…
Sand, Treu, & Ellis (2002) have measured the central density profile of cluster MS2137-23 with gravitational lensing and velocity dispersion and removed the stellar contribution with a reasonable M/L. The resulting dark matter distribution…
Mass estimates of a spiral galaxy derived from its rotation curve must account for the galaxy's past accretion history. There are several lines of evidence indicating that M31 experienced a major merger 2 to 3 Gyr ago. Here, we have…
We propose an analytical method to describe a matter density profile near a galaxy center. The description is based on the study of the distribution function of particles over possible trajectories. We establish a relation between the…
Rotation curves of galaxies probe their total mass distributions, including dark matter. Dwarf galaxies are excellent systems to investigate the dark matter density distribution, as they tend to have larger fractions of dark matter compared…
In the standard Lambda cold dark matter paradigm, pure dark matter simulations predict dwarf galaxies should inhabit dark matter haloes with a centrally diverging density `cusp'. This is in conflict with observations that typically favour a…
Simulations of the clustering of cold dark matter yield dark-matter halos that have central density cusps, but observations of totally dark-matter dominated dwarf spheroidal galaxies imply that they do not have cuspy central density…
Observed cusps with density profiles $\rho\propto r^{-1}$ or shallower, in the central regions of galaxies, cannot be reproduced in the standard Cold Dark Matter (CDM) picture of hierarchical clustering. Previous claims to the contrary were…
We study the statistical properties of mergers between central and satellite galaxies in galaxy clusters in the redshift range $0<z<1$, using a sample of dark-matter only cosmological N-body simulations from Le SBARBINE dataset. Using a…
We propose that the accretion of a dwarf spheroidal galaxy provides a common origin for the giant southern stream and the warp of M31. We run about 40 full N-body simulations with live M31, infalling galaxies with varying masses and density…
We propose and successfully test against new cosmological simulations a novel analytical description of the physical processes associated with the origin of cored dark matter density profiles. In the simulations, the potential in the…
We present the results of N-body simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies. Both galaxies contain power-law central density cusps and point masses representing supermassive black holes; the…
We present N-body simulations of galaxy groups embedded in a common halo of matter. We study the influence of the different initial conditions upon the evolution of the group and show that denser configurations evolve faster, as expected.…
We have developed an effective simulation method and applied it to the problem of the accretion of very dense secondary companions by tenuous primaries. We have studied the accretion of objects of varying luminosity ratios, with sizes and…
We use N-body simulations to study the infall of dark matter haloes onto rich clusters of galaxies. After identification of all cluster progenitors in the simulations, we select those haloes which accrete directly onto the main cluster…
The dynamical evolution of super star clusters has been investigated in dark matter halos depicted with a cuspy- or soft-core density profile. The simulations show that (1) exponential bulges with central cusps form in both cases;(2)…
The rotation curves of some star forming massive galaxies at redshift two decline over the radial range of a few times the effective radius, indicating a significant deficit of dark matter (DM) mass in the galaxy centre. The DM mass deficit…
We explain in simple terms how the buildup of dark haloes by merging compact satellites, as in the CDM cosmology, inevitably leads to an inner cusp of density profile $\rho \propto r^{-\alpha}$ with $\alpha \gsim 1$, as seen in cosmological…
Collapsing collisionless particle systems form gravitational bound halos with cuspy density profiles. Also hierarchical merging of these systems produce remnants with cuspy central density profiles. These results lead to the assumption of…