A Model for the Density Distribution of Virialized Cold Dark Matter Halos

Kull, A.

doi:10.1086/311990

Cited by 17 publications

(21 citation statements)

References 22 publications

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“…Some attempts to incorporate tangential velocities within the framework of spherical symmetry have also been made by [9,65,122]. Along this line, one may also refer to work by [40,63,89,91] and references therein.…”

Section: Previous Analytical Models For Halo Formation: the Sphericalmentioning

confidence: 99%

“…The projected surface density is given by where ξ is the projected distance from the center of the halo, and z = (r 2 − ξ 2 ) 1/2 . For the TIS, we substitute equation (61) in equation (89), and get [68,106]. For spherically symmetric lenses, one important quantity is the interior mass M (ξ) inside a cylinder of projected radius ξ centered around the center of the lens.…”

Section: The Interior Mass Profilementioning

confidence: 99%

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Understanding the Equilibrium Structure of CDM Halos

Shapiro

Ahn

Alvarez

et al. 2006

EAS Publications Series

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N-body simulations find a universal structure for the halos which result from the nonlinear growth of Gaussian-random-noise density fluctuations in the CDM universe. This talk summarized our attempts to derive and explain this universal structure by analytical approximation and simplified models. As an example, we show here that a 1D spherical infall model involving a fluid approximation derived from the Boltzmann equation can explain not only the halo density profile but its phase-space density profile, as well.Comment: To appear in the proceedings of 21st IAP colloquium, "Mass Profiles and Shapes of Comological Structures

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Section: Previous Analytical Models For Halo Formation: the Sphericalmentioning

confidence: 99%

Section: The Interior Mass Profilementioning

confidence: 99%

Understanding the Equilibrium Structure of CDM Halos

Shapiro

Ahn

Alvarez

et al. 2006

EAS Publications Series

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“…Studies based on analytical and seminumerical methods also have shown that eq. (1) is a good approximation for the density profiles of typical equilibrium cold dark matter haloes (e.g., Syer & White 1998; Avila-Reese, Firmani, & Hernández 1998;Salvador-Solé, Manrique & Solanes 1998;Raig, González-Casado & Salvador-Solé 1998;Henriksen & Widrow 1999;Nusser & Sheth 1998;Kull 1999;Lokas 1999). Nevertheless, the applicability of the NFW profile has some limits.…”

Section: Introductionmentioning

confidence: 99%

Density profiles of dark matter haloes: diversity and dependence on environment

Avila-Reese

Firmani

Klypin

et al. 1999

Monthly Notices of the Royal Astronomical Society

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We study the outer density profiles of dark matter haloes predicted by a generalized secondary infall model and observed in a dissipationless cosmological simulation of a low‐density flat cold dark matter model with the cosmological constant. We find substantial systematic variations in shapes and concentrations of the halo profiles as well as a strong correlation of the profiles with the environment in which the haloes are embedded. In the N‐body simulation, the average outer slope of the density profiles, β(ρ∝r‐β), of isolated haloes is β≈2.9, and 68 per cent of these haloes have values of β between 2.5 and 3.8. Haloes in dense environments of clusters are more concentrated and exhibit a broad distribution of β with an average value higher than the average β for isolated haloes. For haloes located within half the virial radius of the cluster from the centre values β≈4 are very common. Contrary to what one may expect, the haloes contained within groups and galaxy systems are less concentrated and have flatter outer density profiles than the isolated haloes: the distribution of β peaks at ≈2.3–2.7. The slope β weakly anticorrelates with the halo mass Mh. The concentration decreases with Mh, but its scatter is roughly equal to the whole variation of this parameter in the galaxy halo mass range. The mass and circular velocity of the haloes are strongly correlated, , with α≈3.3 and ≈3.5 for the isolated haloes and haloes in clusters, respectively. For Mh≈1012 h‐1 M⊙ the rms deviations from these relations are Δ log Mh=0.12 and 0.18, respectively. Approximately 30 per cent of the haloes are contained within larger haloes or have massive companions within three virial radii. The companions are allowed to have masses larger than ∼0.3 times the mass of the current halo. The remaining 70 per cent of the haloes are isolated objects. We find that the distribution of β as well as the concentration–mass and Mh–Vm relations for the isolated haloes agree very well with the predictions of our seminumerical approach, which is based on a generalization of the secondary infall model and on the extended Press–Schechter formalism.

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“…There are good reasons for this: LSB galaxies are dark matter dominated down to small radii, making the inference of their dark matter properties much less sensitive to the stellar mass than in higher surface brightness spirals. In the most straightforward analyses, the data appear to contradict a basic prediction of the ΛCDM structure formation scenario, that dark matter halos should have cusps at small radii (a density distribution ρ ∼ r −γ with γ ≈ 1: Dubinski 1994;Cole & Lacey 1996;Navarro, Frenk, & White 1997 (hereafter NFW); Tormen, Bouchet, & White 1997;Moore et al 1998Moore et al , 1999bTissera & Dominguez-Tenreiro 1998;Nusser & Sheth 1998;Syer & White 1998;Avila-Reese, Firmiani, & Hernandez 1998;Salvador-Śole, Solanes, & Manrique 1998;Jing 2000;Jing & Suto 2000;Kull 1999;Klypin et al 2001;Ricotti 2003;Power et al 2003;Diemand et al 2005). The data are apparently more consistent with a nearly constant density core (γ ≈ 0).…”

mentioning

confidence: 97%

The Rotation Velocity Attributable to Dark Matter at Intermediate Radii in Disk Galaxies

McGaugh

Blok

Schombert

et al. 2007

ApJ

107

132

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We examine the amplitude of the rotation velocity that can be attributed to the dark matter halos of disk galaxies, focusing on well measured intermediate radii. The data for 60 galaxies spanning a large range of mass and Hubble types, taken together, are consistent with a dark halo velocity log V h = C + B log r with C = 1.47 +0.15 −0.19 and B ≈ 1 2 over the range 1 < r < 74 kpc. The range in C stems from different choices of the stellar mass estimator, from minimum to maximum disk. For all plausible choices of stellar mass, the implied densities of the dark halos are lower than expected from structure formation simulations in ΛCDM, which anticipate C > 1.6. This problem is not specific to a particular type of galaxy or to the innermost region of the halo (cusp or core); the velocity attributable to dark matter is too low at all radii.

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A Model for the Density Distribution of Virialized Cold Dark Matter Halos

Cited by 17 publications

References 22 publications

Understanding the Equilibrium Structure of CDM Halos

Understanding the Equilibrium Structure of CDM Halos

Density profiles of dark matter haloes: diversity and dependence on environment

The Rotation Velocity Attributable to Dark Matter at Intermediate Radii in Disk Galaxies

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