scholarly journals The Phase‐Space Density Profiles of Cold Dark Matter Halos

2001 ◽  
Vol 563 (2) ◽  
pp. 483-488 ◽  
Author(s):  
James E. Taylor ◽  
Julio F. Navarro
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Cold Dark Matter ◽  
Phase Space Density ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Space Density

scholarly journals The density and pseudo-phase-space density profiles of cold dark matter haloes

2011 ◽  
Vol 415 (4) ◽  
pp. 3895-3902 ◽  
Author(s):  
Aaron D. Ludlow ◽  
Julio F. Navarro ◽  
Simon D. M. White ◽  
Michael Boylan-Kolchin ◽  
Volker Springel ◽  
...  
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Cold Dark Matter ◽  
Phase Space Density ◽  
Density Profiles ◽  
Space Density

scholarly journals DISTRIBUTION FUNCTION IN THE CENTER OF THE DARK MATTER HALO

2009 ◽  
Vol 18 (03) ◽  
pp. 477-484
Author(s):  
DING MA ◽  
PING HE
Keyword(s):  
Dark Matter ◽  
Distribution Function ◽  
Phase Space ◽  
Velocity Dispersion ◽  
Anisotropy Parameter ◽  
Dark Matter Halo ◽  
Phase Space Density ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Space Density

N-body simulations of dark matter halos show that the density profiles of the halos behave as ρ(r) ∝ r-α(r), where the density logarithmic slope α ≃ 1–1.5 in the center and α ≃ 3–4 in the outer parts of the halos. However, some observations are not in agreement with simulations in the very central region of the halos. The simulations also show that the velocity dispersion anisotropy parameter β ≈ 0 in the inner part of the halo and the so-called pseudo–phase-space density ρ/σ3 behaves as a power law in radius r. With these results in mind, we study the distribution function and the pseudo–phase-space density ρ/σ3 of the center of dark matter halos and find that they are closely related.

scholarly journals Secondary infall and the pseudo-phase-space density profiles of cold dark matter haloes

2010 ◽  
Vol 406 (1) ◽  
pp. 137-146 ◽  
Author(s):  
Aaron D. Ludlow ◽  
Julio F. Navarro ◽  
Volker Springel ◽  
Mark Vogelsberger ◽  
Jie Wang ◽  
...  
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Cold Dark Matter ◽  
Phase Space Density ◽  
Density Profiles ◽  
Space Density

scholarly journals On the apparent power law in CDM halo pseudo-phase space density profiles

2017 ◽  
Vol 470 (1) ◽  
pp. 500-511 ◽  
Author(s):  
Ethan O. Nadler ◽  
S. Peng Oh ◽  
Suoqing Ji
Keyword(s):  
Phase Space ◽  
Power Law ◽  
Cold Dark Matter ◽  
Initial Conditions ◽  
Phase Space Density ◽  
Fluid Approximation ◽  
Density Profiles ◽  
Space Density ◽  
Scale Free ◽  
Hydrodynamic Calculations

Abstract We investigate the apparent power-law scaling of the pseudo-phase space density (PPSD) in cold dark matter (CDM) haloes. We study fluid collapse, using the close analogy between the gas entropy and the PPSD in the fluid approximation. Our hydrodynamic calculations allow for a precise evaluation of logarithmic derivatives. For scale-free initial conditions, entropy is a power law in Lagrangian (mass) coordinates, but not in Eulerian (radial) coordinates. The deviation from a radial power law arises from incomplete hydrostatic equilibrium (HSE), linked to bulk inflow and mass accretion, and the convergence to the asymptotic central power-law slope is very slow. For more realistic collapse, entropy is not a power law with either radius or mass due to deviations from HSE and scale-dependent initial conditions. Instead, it is a slowly rolling power law that appears approximately linear on a log–log plot. Our fluid calculations recover PPSD power-law slopes and residual amplitudes similar to N-body simulations, indicating that deviations from a power law are not numerical artefacts. In addition, we find that realistic collapse is not self-similar; scalelengths such as the shock radius and the turnaround radius are not power-law functions of time. We therefore argue that the apparent power-law PPSD cannot be used to make detailed dynamical inferences or extrapolate halo profiles inwards, and that it does not indicate any hidden integrals of motion. We also suggest that the apparent agreement between the PPSD and the asymptotic Bertschinger slope is purely coincidental.

On the Pseudo Phase-space Density of Dark Matter Haloes and the Universality of Density Profiles

2015 ◽  
Vol 24 (3) ◽  
Author(s):  
A. Del Popolo
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Radial Dependence ◽  
Phase Space Density ◽  
Density Profiles ◽  
Space Density

AbstractWe examine the radial dependence of the pseudo phase-space density,

scholarly journals Evolution of the Phase‐Space Density in Dark Matter Halos

2007 ◽  
Vol 671 (2) ◽  
pp. 1108-1114 ◽  
Author(s):  
Yehuda Hoffman ◽  
Emilio Romano‐Diaz ◽  
Isaac Shlosman ◽  
Clayton Heller
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Phase Space Density ◽  
Dark Matter Halos ◽  
Space Density

scholarly journals The Phase-space Density Distribution of Dark Matter Halos

2004 ◽  
Author(s):  
Liliya L. R. Williams ◽  
Crystal Austin ◽  
Eric Barnes ◽  
Arif Babul ◽  
Julianne Dalcanton
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Density Distribution ◽  
Phase Space Density ◽  
Dark Matter Halos ◽  
Space Density

scholarly journals NIHAO project II: halo shape, phase-space density and velocity distribution of dark matter in galaxy formation simulations

2016 ◽  
Vol 462 (1) ◽  
pp. 663-680 ◽  
Author(s):  
Iryna Butsky ◽  
Andrea V. Macciò ◽  
Aaron A. Dutton ◽  
Liang Wang ◽  
Aura Obreja ◽  
...  
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Velocity Distribution ◽  
Galaxy Formation ◽  
Phase Space Density ◽  
Space Density

scholarly journals Structure of Dark Matter Halo

1999 ◽  
Vol 183 ◽  
pp. 155-155
Author(s):  
Toshiyuki Fukushige ◽  
Junichiro Makino
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Temperature Inversion ◽  
Dark Matter Halo ◽  
Temperature Structure ◽  
Galactic Halos ◽  
Dark Matter Halos ◽  
Density Profiles ◽  
Order Of Magnitude ◽  
Special Purpose Computer

We performed N-body simulation on special-purpose computer, GRAPE-4, to investigate the structure of dark matter halos (Fukushige, T. and Makino, J. 1997, ApJL, 477, L9). Universal profile proposed by Navarro, Frenk, and White (1996, ApJ, 462, 563), which has cusp with density profiles ρ ∝r−1in density profile, cannot be reproduced in the standard Cold Dark Matter (CDM) picture of hierarchical clustering. Previous claims to the contrary were based on simulations with relatively few particles, and substantial softening. We performed simulations with particle numbers an order of magnitude higher, and essentially no softening, and found that typical central density profiles are clearly steeper than ρ ∝r−1, as shown in Figure 1. In addition, we confirm the presence of a temperature inversion in the inner 5 kpc of massive galactic halos, and give a natural explanation for formation of the temperature structure.

Sign in / Sign up

Export Citation Format

Share Document