2008/02/13 by Alexander Knebe, Nadya Draganova, Chris Power +6
Physics and Astronomy · #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1745-3933.2008.00459.x
5 pages, 2 figures. MNRAS Letter, in press
arxiv created 2008/02/13 · openalex publication_date 2008/03/07 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Abstract We explore the dependence of the radial alignment of subhaloes on the mass of the host halo they orbit in. As the effect is seen on a broad range of scales including massive clusters as well as galactic systems it only appears natural to explore this phenomenon by means of cosmological simulations covering the same range in masses. We have 25 well resolved host dark matter haloes at our disposal ranging from 1015h−1 M⊙ down to 1012h−1 M⊙ each consisting of order of a couple of million particles within the virial radius. We observe that subhaloes tend to be more spherical than isolated objects. Both the distributions of sphericity and triaxiality of subhaloes are Gaussian-distributed with peak values of 〈s〉≈ 0.80 and 〈T〉≈ 0.56, irrespective of host mass. Interestingly, we note that the radial alignment is independent of host halo mass and the distribution of cos θ (i.e. the angle between the major-axis Ea of each subhalo and the radius vector of the subhalo in the reference frame of the host) is well fitted by a simple power law P(cos θ) ∝ cos4θ with the same fitting parameters for all host haloes.