Related papers: Can dark matter see itself?
The crisis of the cold dark matter and problems of the self-interacting dark matter models is resolved by postulating flavor mixing of dark matter particles. Flavor-mixed particles segregate in the gravitational field to form dark halos…
Using an analytic model calibrated against numerical simulations, we calculate the central densities of dark matter halos in a ``conventional'' cold dark matter model with a cosmological constant (LCDM) and in a ``tilted'' model (TLCDM)…
The longstanding cusp-core problem--the discrepancy between the steep central density cusps predicted by cold dark matter (DM) simulations and certain shallow cores observed in dwarf galaxies, in particular the associated diversity of inner…
We present a synthesis of recent photometric and kinematic data for several of the most dark-matter dominated galaxies. There is a bimodal distribution in half-light radii, with stable star clusters always being smaller than $\sim30$pc,…
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…
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…
Dissipative dark matter self-interactions can affect halo evolution and change its structure. We perform a series of controlled N-body simulations to study impacts of the dissipative interactions on halo properties. The interplay between…
Although high-resolution N-body simulations make robust empirical predictions for the density distribution within cold dark matter halos, these studies have yielded little physical insight into the origins of the distribution. We…
Well known scaling laws among the structural properties of the dark and the luminous matter in disc systems are too complex to be arisen by two inert components that just share the same gravitational field. This brings us to critically…
It has been proposed that the stellar cores observed in ultra-faint dwarf (UFD) galaxies reflect underlying dark matter (DM) cores that cannot be formed by stellar feedback acting on collisionless cold dark matter (CDM) halos. Assuming this…
Numerical simulation is an important tool to help us understand the process of structure formation in the universe. However many simulation results of cold dark matter (CDM) halos on small scale are inconsistent with observations: the…
Cold dark matter haloes are populated by high-density structures with sharply-peaked profiles known as caustics which have not yet been resolved by 3-dimensional numerical simulations. Here, we derive semi-analytic expressions for the…
Recent Strong lensing data and rotation curves of dwarf galaxies indicate that many galactic clusters may have a soft core instead of a central cusp in their density distribution. This result challenges the standard CDM (Cold Dark Matter)…
Spergel & Steinhardt proposed the possibility that the dark matter particles are self-interacting, as a solution to two discrepancies between the predictions of cold dark matter models and the observations: first, the observed dark matter…
There exists considerable interest in dark matter candidates that can reduce cosmological structure at sub-galactic scales through a suppression of the power spectrum of primordial perturbations as well as have a primordial velocity…
We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…
Can N-body simulations reliably determine the structural properties of dark matter halos? Focussing on a Virgo-sized galaxy cluster, we increase the resolution of current ``high resolution simulations'' by almost an order of magnitude to…
After deducing the density profiles and gravitational potential functions of eight galaxies from the rotation velocity data from THINGS, we find that the density decreases exponentially with the potential in substantial regions of the…
N-body simulations and analytical calculations of the gravitational collapse in an expanding universe predict that halos should form with a diverging inner density profile, the cusp. There are some observational indications that the dark…
I use $N$-body simulations to investigate the morphology and the dynamical evolution and properties of dark matter halos in clusters of galaxies. My sample consists of nine massive halos, coming from an Einstein-de Sitter universe with…