scholarly journals Dark Matter Density in Disk Galaxies

2008 ◽  
Vol 4 (S254) ◽  
pp. 73-84
Author(s):  
J. A. Sellwood
Keyword(s):  
Dark Matter ◽  
Structure Formation ◽  
Matter Density ◽  
Disk Galaxies ◽  
Dark Matter Halos ◽  
Dynamical Friction ◽  
Physical Processes ◽  
Dark Matter Density ◽  
Density Reduction ◽  
Λcdm Model

AbstractI show that the predicted densities of the inner dark matter halos in ΛCDM models of structure formation appear to be higher than estimates from real galaxies and constraints from dynamical friction on bars. This inconsistency would not be a problem for the ΛCDM model if physical processes that are omitted in the collisionless collapse simulations were able to reduce the dark matter density in the inner halos. I review the mechanisms proposed to achieve the needed density reduction.

scholarly journals The dark matter density problem in massive disk galaxies

2004 ◽  
Vol 220 ◽  
pp. 265-270 ◽  
Author(s):  
Benjamin J. Weiner
Keyword(s):  
Dark Matter ◽  
Angular Momentum ◽  
Momentum Transfer ◽  
Matter Density ◽  
Disk Galaxies ◽  
Dark Matter Halos ◽  
Barred Galaxies ◽  
Dark Matter Density ◽  
Disk Mass ◽  
Density Problem

We discuss measurements of disk mass from non-circular streaming motions of gas in the barred galaxies NGC 3095 and NGC 4123. in these galaxies with strong shocks and non-circular motions, the inner regions must be disk-dominated to reproduce the shocks. This requires dark matter halos of low central density and low concentration, compared to LCDM halo predictions. in addition, the baryonic collapse to a disk should have compressed the halo and increased the dark matter density, which sharpens the disagreement. One possible resolution is a substantial amount of angular momentum transfer from disk to halo, but this is not particularly attractive nor elegant.

scholarly journals Dark matter density profile and galactic metric in Eddington-inspired Born–Infeld gravity

2014 ◽  
Vol 29 (09) ◽  
pp. 1450049 ◽  
Author(s):  
Tiberiu Harko ◽  
Francisco S. N. Lobo ◽  
M. K. Mak ◽  
Sergey V. Sushkov
Keyword(s):  
Dark Matter ◽  
Gravitational Field ◽  
Density Profile ◽  
Galactic Center ◽  
Matter Density ◽  
Dark Matter Halos ◽  
Field Equations ◽  
Metric Tensor ◽  
Dark Matter Density ◽  
Gravitational Field Equations

We consider the density profile of pressureless dark matter in Eddington-inspired Born–Infeld (EiBI) gravity. The gravitational field equations are investigated for a spherically symmetric dark matter galactic halo, by adopting a phenomenological tangential velocity profile for test particles moving in stable circular orbits around the galactic center. The density profile and the mass distribution, as well as the general form of the metric tensor is obtained by numerically integrating the gravitational field equations, and in an approximate analytical form by using the Newtonian limit of the theory. In the weak field limit, the dark matter density distribution is described by the Lane–Emden equation with polytropic index n = 1, and is nonsingular at the galactic center. The parameter κ of the theory is determined so that the theory could provide a realistic description of the dark matter halos. The gravitational properties of the dark matter halos are also briefly discussed in the Newtonian approximation.

On the Mass Dependence of the Inner Slopes of Dark Matter Density Profiles

2014 ◽  
Vol 23 (1) ◽  
Author(s):  
A. Del Popolo
Keyword(s):  
Dark Matter ◽  
Matter Density ◽  
Mass Dependence ◽  
Analytic Model ◽  
Dark Matter Halos ◽  
Logarithmic Density ◽  
Density Profiles ◽  
Dark Matter Density

AbstractWe study through a semi-analytic model how the inner slopes of relaxed ΛCDM dark matter halos with and without baryons depend on the halo mass. We find that the inner logarithmic density slope, α ≡

Constraints on the Clumpiness of Dark Matter Halos Through Heating of Disk Galaxies

2003 ◽  
Vol 10 ◽  
pp. 95-95
Author(s):  
E. Ardi ◽  
T. Tsuchiya ◽  
A. Burkert
Keyword(s):  
Dark Matter ◽  
Disk Galaxies ◽  
Dark Matter Halos

scholarly journals Determining the local dark matter density with LAMOST data

2016 ◽  
Vol 458 (4) ◽  
pp. 3839-3850 ◽  
Author(s):  
Qiran Xia ◽  
Chao Liu ◽  
Shude Mao ◽  
Yingyi Song ◽  
Lan Zhang ◽  
...  
Keyword(s):  
Dark Matter ◽  
Matter Density ◽  
Dark Matter Density

scholarly journals Isolated dwarf galaxies: from cuspy to flat dark matter density profiles and metalicity gradients

2010 ◽  
Vol 514 ◽  
pp. A47 ◽  
Author(s):  
S. Pasetto ◽  
E. K. Grebel ◽  
P. Berczik ◽  
R. Spurzem ◽  
W. Dehnen
Keyword(s):  
Dark Matter ◽  
Dwarf Galaxies ◽  
Matter Density ◽  
Density Profiles ◽  
Dark Matter Density

scholarly journals Non-Gaussian inference from non-linear and non-Poisson biased distributed data

2014 ◽  
Vol 10 (S306) ◽  
pp. 258-261
Author(s):  
Metin Ata ◽  
Francisco-Shu Kitaura ◽  
Volker Müller
Keyword(s):  
Dark Matter ◽  
Statistical Inference ◽  
Computer Code ◽  
Matter Density ◽  
Density Field ◽  
Distributed Data ◽  
Dark Matter Density ◽  
Posterior Sampling ◽  
Non Linear ◽  
Non Gaussian

AbstractWe study the statistical inference of the cosmological dark matter density field from non-Gaussian, non-linear and non-Poisson biased distributed tracers. We have implemented a Bayesian posterior sampling computer-code solving this problem and tested it with mock data based onN-body simulations.

scholarly journals Recoiling black holes in static and evolving dark matter halo potential

2015 ◽  
pp. 17-28 ◽  
Author(s):  
M. Smole
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Critical Velocity ◽  
Complete Removal ◽  
Matter Density ◽  
Dark Matter Halo ◽  
Dark Matter Halos ◽  
Critical Amplitude ◽  
Density Distributions

We follow trajectories of kicked black holes in static and evolving dark matter halo potential. We explore both NFW and Einasto dark matter density distributions. Considered dark matter halos represent hosts of massive spiral and elliptical field galaxies. We study critical amplitude of kick velocity necessary for complete black hole ejection at various redshifts and find that ~40% lower kick velocities can remove black holes from their host haloes at z = 7 compared to z = 1. The greatest difference between static and evolving potential occurs near the critical velocity for black hole ejection and at high redshifts. When NFW and Einasto density distributions are compared ~30% higher kick velocities are needed for complete removal of BHs from dark matter halo described by NFW profile.

Sign in / Sign up

Export Citation Format

Share Document