Related papers: On Universal Halos and the Radial Orbit Instabilit…
For a decade, N-body simulations have revealed a nearly universal dark matter density profile, which appears to be robust to changes in the overall density of the universe and the underlying power spectrum. Despite its universality, the…
Using N-body simulations we study the phenomenon of radial orbit instability occurring in dark matter haloes of the size of a dwarf galaxy. We carried out simulations of seven spherical models, with the same standard NFW density profile but…
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…
The radial-orbit instability is a collective phenomenon that has heretofore only been observed in spherical systems. We find that this instability occurs also in triaxial systems, as we checked by performing extensive N-body simulations…
Among the most fundamental properties of a dark matter halo is its density profile. Motivated by the recent proposal by Garc\'ia et al. [R. Garc\'ia et. al., MNRAS 521, 2464 (2023)] to define a dynamical halo as the collection of orbiting…
In the past years a wealth of observations allowed to unravel the structural properties of the Dark Matter Halos around spirals. First, their rotation curves follow an Universal profile (URC) that can be described in terms of an exponential…
We explore a series expansion method to calculate the modes of oscillations for a variety of uniformly rotating finite disks, either with or without a dark halo. Since all models have the same potential, this survey focuses on the role of…
We analyze the physical justification of the picture proposed by Salvador-Sole et al. in these proceedings for the time evolution of the universal density profile of dark-matter halos. According to this picture, halos have at formation a…
This paper is devoted to Radial Orbit Instability in the context of self-gravitating dynamical systems. We present this instability in the new frame of Dissipation-Induced Instability theory. This allows us to obtain a rather simple proof…
The late infall of dark matter onto a galaxy produces structure (such as caustics) in the distribution of dark matter in the halo. We argue that such structure is likely to occur generically on length scales proportional to $l \sim t_0…
We argue that a universal density profile for dark matter halos arises as a natural consequence of hierarchical structure formation. It is a fixed point in the process of repeated mergers. We present analytic and numerical arguments for the…
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…
Thanks to the ever increasing computational power and the development of more sophisticated algorithms, numerical N-body simulations are now uncovering several phenomenological relations between the physical properties of dark matter haloes…
Self-consistent solutions for triaxial mass models are highly non-unique. In general, some of these solutions might be dynamically unstable, making them inappropriate as descriptions of steady-state galaxies. Here we demonstrate for the…
Dark-matter halos show a universal density profile with a scaling such that less massive systems are typically denser. This mass-density relation is well described by a proportionality between the characteristic density of halos and the…
Cosmological N--body simulations have revealed a remarkable similarity in the structure of dark matter halos formed in hierarchically clustering universes. Regardless of halo mass, cosmological parameters, and power spectrum of initial…
The rotation curves of dark matter dominated dwarf galaxies are analysed. The observations show that dark matter halos represent a one-parameter family with self similar density profiles. The global halo parameters, like total mass and…
Stationary stellar systems with radially elongated orbits are subject to radial orbit instability -- an important phenomenon that structures galaxies. Antonov (1973) presented a formal proof of the instability for spherical systems in the…
Cosmological models in which dark matter consists of cold elementary particles predict that the dark halo population should extend to masses many orders of magnitude below those at which galaxies can form. Here we report a cosmological…
The Rayleigh criterion is used to study the stability of circular orbits of particles moving around static black holes surrounded by different axially symmetric structures with reflection symmetry, like disks, rings and halos. We consider…