Results 21 to 30 of about 454,773 (69)
Contradiction between strong lensing statistics and a feedback solution to the cusp/core problem [PDF]
Res.Astron.Astrophys.10:1215-1222,2010, 2008 Standard cosmology has many successes on large scales, but faces some fundamental difficulties on small, galactic scales. One such difficulty is the cusp/core problem. High resolution observations of the rotation curves for dark matter dominated low surface brightness (LSB) galaxies imply that galactic dark matter halos have a density profile with a ...
arxiv +1 more source
Merger Histories in Warm Dark Matter Structure Formation Scenario [PDF]
Mon.Not.Roy.Astron.Soc. 329 (2002) 813, 2001 Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by introducing self-interacting cold dark matter particles to a tuning of complex astrophysical processes such as global
arxiv +1 more source
An analytic distribution function for a massless cored stellar system in a cuspy dark matter halo [PDF]
, 2013 We demonstrate the existence of distribution functions that can be used to represent spherical massless cored stellar systems embedded in cuspy dark matter halos with constant mildly tangential velocity anisotropy. In particular, we derive analytically the functional form of the distribution function for a Plummer stellar sphere in a Hernquist dark ...
arxiv +1 more source
The origin and tidal evolution of cuspy triaxial haloes [PDF]
Mon.Not.Roy.Astron.Soc. 354 (2004) 522, 2003 We present a technique for constructing equilibrium triaxial N-body haloes with nearly arbitrary density profiles, axial ratios and spin parameters. The method is based on the way in which structures form in hierarchical cosmological simulations, where prolate and oblate haloes form via mergers with low and high angular momentum, respectively.
arxiv +1 more source
Detecting a physical difference between the CDM halos in simulation and in nature [PDF]
, 2005 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 central density profile is too cuspy and there are too many substructures.
arxiv +1 more source
The connection between the cusp-to-core transformation and observational universalities of DM halos [PDF]
, 2013 Observations have revealed interesting universal properties of dark matter (DM) halos especially around low-mass galaxies. Strigari et al. (2008) showed that DM halos have common enclosed masses within 300pc (Strigari relation). Kormendy & Freeman (2004) reported DM halos having almost identical central surface densities (the $\mu_{\rm 0D}$ relation ...
arxiv +1 more source
Galaxy cluster mass profiles [PDF]
Mon.Not.Roy.Astron.Soc.368:518-533,2006, 2006 Accurate measurements of the mass distribution in galaxy and cluster halos are essential to test the cold dark matter (CDM) paradigm. The cosmological model predicts a universal shape for the density profile in all halos, independent of halo mass. Its profile has a `cuspy' centre, with no evidence for the constant density core.
arxiv +1 more source
Super cuspy dark matter halos of massive galaxies due to baryon-driven contraction [PDF]
arXiv, 2023 The interplay between dark matter (DM) and baryons has long been ignored when building galaxies semi-empirically and observationally. Here I show that baryonic gravity leads to an adiabatic contraction of DM halos, which is most significant in massive galaxies. Ignoring this effect, the derived DM halos are not guaranteed in dynamical equilibrium.
arxiv
Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies [PDF]
, 2012 We examine the evolution of the inner dark matter (DM) and baryonic density profile of a new sample of simulated field galaxies using fully cosmological, Lambda CDM, high resolution SPH + N-Body simulations. These simulations include explicit H2 and metal cooling, star formation (SF) and supernovae (SNe) driven gas outflows.
arxiv +1 more source
Inner Halo Shapes of Dwarf Galaxies: Resolving the Cusp/Core Problem [PDF]
arXiv, 2003 We derive inner dark matter halo density profile slopes for a sample of 200 dwarf galaxies by inverting rotation curves obtained from high-quality, long-slit optical spectra. Using simulations to assess the impact of long-slit observing and data processing errors on our measurements, we conclude that our observations are consistent with the cuspy halos
arxiv