Related papers: Large scale anisotropies on halo infall
Dark matter particles form halos that contribute the major part of the mass of galaxy clusters. The formation of these cosmological structures have been investigated both observationally and in numerical simulations, which have confirmed…
We use seven high-resolution $N$-body simulations to study the correlations among different halo properties (assembly time, spin, shape and substructure), and how these halo properties are correlated with the large-scale environment in…
Based on long baseline (5-7 years) multi-epoch HST/ACS photometry, used previously to measure the proper motion of M31, we present the proper motions (PMs) of 13 main-sequence Milky Way halo stars. The sample lies at an average distance of…
We use a set of cosmological N-body simulations to investigate the structural shape of galaxy-sized cold dark matter (CDM) halos. Unlike most previous work on the subject - which dealt with shapes as measured by the inertia tensor - we…
We use group size haloes identified with a ``friends of friends'' (FOF) algorithm in a concordance $\Lambda \rm{CDM}$ GADGET2 (dark matter only) simulation to investigate the dependence of halo properties on the environment at $z=0$. The…
We study the phase-space structure of a dark-matter halo formed in a high resolution simulation of a Lambda CDM cosmology. Our goal is to quantify how much substructure is left over from the inhomogeneous growth of the halo, and how it may…
In a recent paper, Salvador-Sol\'e et al. (2012) have derived the typical inner structure of dark matter haloes from that of peaks in the initial random Gaussian density field, determined by the power-spectrum of density perturbations…
We analyze the spatial anisotropy and the velocity anisotropy in a set of mock stellar halos from the Aquarius simulations. The spatial anisotropy in each mock stellar halo rises progressively with the increasing distance from the halo…
Using constrained simulations of the local Universe for generic cold dark matter and for 1keV warm dark matter, we investigate the difference in the abundance of dark matter halos in the local environment. We find that the mass function…
We investigate a hypothesis regarding the origin of the scalelength in halos formed in cosmological N-body simulations. This hypothesis can be viewed as an extension of an earlier idea put forth by Merritt and Aguilar. Our findings suggest…
We use a set of large cosmological N-body simulations to study the internal structure of dark matter haloes which form in scale-free models. We find that the radius r_178 corresponding to a mean interior overdensity of 178 accurately…
We explore the hypothesis that clouds detected in quasar absorption line systems are falling at a terminal velocity toward the center of high redshift gaseous galactic halos. Since both the ionization level and terminal velocity of halo…
Understanding the formation of the first objects in the universe critically depends on knowing whether the properties of small dark matter structures at high-redshift (z > 15) are different from their more massive lower-redshift…
We explore the boundary of dark matter haloes through their bias and velocity profiles. Using cosmological $N$-body simulations, we show that the bias profile exhibits a ubiquitous trough that can be interpreted as created by halo accretion…
Both simulations and observations have confirmed that the spin of haloes/galaxies is correlated with the large scale structure (LSS) with a mass dependence such that the spin of low-mass haloes/galaxies tend to be parallel with the LSS,…
We investigate the effects of intrinsic alignments (IA) of dark-matter halo shapes on cosmic density and velocity fields from cluster to cosmic scales beyond 100 Mpc/h. Besides the density correlation function binned by the halo orientation…
The detection of byproducts from particle annihilations in galactic halos would provide important information about the nature of the dark matter. Observational evidence for a local excess of high-energy positrons has motivated recent…
The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…
We use high-resolution numerical simulations to study the physical properties of subhalos when they merge into their host halos. An improved algorithm is used to identify the subhalos. We then examine their spatial and velocity…
Motivated by the recent detection of an enhanced clustering signal along the major axis of haloes in N-body simulations, we derive a formula for the anisotropic density distribution around haloes and voids on large scales. Our model, which…