The growth and structure of dark matter haloes

Zhao, Deng; Mo, H. J.; Jing, Y. P.; Börner, G.

doi:10.1046/j.1365-8711.2003.06135.x

Cited by 336 publications

(328 citation statements)

References 28 publications

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“…This characteristic scale factor a = ac is the point when the logarithmic mass accretion rate, d log M/d log a, falls below a critical value S = 2 (Wechsler et al 2002). Similar results were found by Zhao et al (2003a; using high-resolution simulations and by van den Bosch (2002) using extended Press-Schechter theory. In a cosmological spherical collapse model, the shell collapse time is determined by the mean initial over-density within the mass shell; the mass within a mass shell collapses when the average linear over-density (calculated using linear perturbation theory) reaches δc ≈ 1.686.…”

Section: Initial Conditions and Methodssupporting

confidence: 80%

“…NFW conjectured that the dependence of halo concentration parameter on halo mass could be explained by the assembly of more massive halos at later times than lower-mass halos. Later, Wechsler et al (2002) and Zhao et al (2003a; found that the concentration of a halo depends on the assembly history. Together, these results suggest that CDM initial conditions play an important role in determining halo density profiles.…”

Section: Introductionmentioning

confidence: 99%

“…Based on highresolution N -body simulations, the mass accretion history of a halo in general consists of two distinct phases: an early fast phase and a later slow phase (Wechsler et al 2002;Zhao et al 2003a,b;Li et al 2005). As shown in Zhao et al (2003a), the fast accretion phase is dominated by major mergers characterised by a rapid deepening of the halo potential. The slow accretion phase is characterised by only weak changes in the gravitational potential well.…”

Section: Introductionmentioning

confidence: 99%

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The origin of cold dark matter halo density profiles

2006

EAS Publications Series

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N -body simulations predict that CDM halo-assembly occurs in two phases: 1) a fast accretion phase with a rapidly deepening potential well; and 2) a slow accretion phase characterised by a gentle addition of mass to the outer halo with little change in the inner potential well. We demonstrate, using one-dimensional simulations, that this two-phase accretion leads to CDM halos of the NFW form and provides physical insight into the properties of the mass accretion history that influence the final profile. Assuming that the velocities of CDM particles are effectively isotropised by fluctuations in the gravitational potential during the fast accretion phase, we show that gravitational collapse in this phase leads to an inner profile ρ(r) ∝ r −1 . Slow accretion onto an established potential well leads to an outer profile with ρ(r) ∝ r −3 . The concentration of a halo is determined by the fraction of mass that is accreted during the fast accretion phase. Using an ensemble of realistic mass accretion histories, we show that the model predictions of the dependence of halo concentration on halo formation time, and hence the dependence of halo concentration on halo mass, and the distribution of halo concentrations all match those found in cosmological N -body simulations. Using a simple analytic model that captures much of the important physics we show that the inner r −1 profile of CDM halos is a natural result of hierarchical mass assembly with a initial phase of rapid accretion.

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Section: Initial Conditions and Methodssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The origin of cold dark matter halo density profiles

2006

EAS Publications Series

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“…Cosmological simulations show that the halo concentration depends on both halo mass and redshift at which the halo is identified (e.g. Bullock et al 2001;Eke, Navarro & Steinmetz 2001;Zhao et al 2003Zhao et al , 2009Macciò et al 2007). Here we adopt the recent simulation result of Prada et al (2012) to compute c for a halo with a given mass at a given redshift.…”

Section: Formation History and Structure Of Dark Matter Halosmentioning

confidence: 99%

Formation of disc galaxies in preheated media: a preventative feedback model

Lu¹,

Mo²

2014

Monthly Notices of the Royal Astronomical Society

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We introduce a semi-analytic galaxy formation model implementing a self-consistent treatment for the hot halo gas configuration and the assembly of central disks. Using the model, we explore a preventative feedback model, in which the circum-halo medium is assumed to be preheated up to a certain entropy level by early starbursts or other processes, and compare it with an ejective feedback model, in which baryons are first accreted into dark matter halos and subsequently ejected out by feedback. The model demonstrates that when the medium is preheated to an entropy comparable to the halo virial entropy the baryon accretion can be largely reduced and delayed. In addition, the preheated medium can establish an extended low density gaseous halo when it accretes into the dark matter halos, and result in a specific angular momentum of the cooling gas large enough to form central disks as extended as those observed. Combined with simulated halo assembly histories, the preventative feedback model can reproduce remarkably well a number of observational scaling relations. These include the cold baryon (stellar plus cold gas) mass fraction-halo mass relations, star formation histories, disk size-stellar mass relation and its evolution, and the number density of low-mass galaxies as a function of redshift. In contrast, the conventional ejective feedback model fails to reproduce these observational trends. Using the model, we demonstrate that the properties of disk galaxies are closely tied to the thermal state of hot halo gas and even possibly the circum-halo medium, which suggests that observational data for the disk properties and circum-galactic hot/warm medium may jointly provide interesting constraints for galaxy formation models.

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“…First, the halo growth has been recognized (see Zhao et al 2003;Wechsler et al 2006;Hoffman et al 2007;Diemand et al 2007) to comprise two stages: an early fast collapse including a few violent major mergers, that builds up the halo main "body" with the structure set by dynamical relaxation; and a later, quasi-equilibrium stage when the body is nearly unaffected, while the outskirts develop from the inside-out by minor mergers and smooth accretion (see Salvador-Solé et al 2007). The transition is provided by the time when a DM gravitational potential attains its maximal depth; i.e., the radial peak of the circular velocity v 2 c ≡ GM/R attains its maximal height, along a given growth history (see Li et al 2007).…”

Section: Two-stage Evolutionmentioning

confidence: 99%

Gamma rays from annihilations at the galactic center in a physical dark matter distribution

Lapi

Paggi²,

Cavaliere³

et al. 2010

A&A

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We discuss the γ-ray signal to be expected from dark matter (DM) annihilations at the Galactic center. We describe the DM distribution in the Galactic halo, based on the Jeans equation for self-gravitating, anisotropic equilibria. In solving the Jeans equation, we adopted the specific correlation between the density ρ(r) and the velocity dispersion σ 2 r (r) expressed by the powerlaw behavior of the DM "entropy" K ≡ σ 2 r /ρ 2/3 ∝ r α with α ≈ 1.25−1.3. Indicated (among others) by several recent N-body simulations, this correlation is privileged by the form of the radial pressure term in the Jeans equation, and it yields a main-body profile consistent with the classic self-similar development of DM halos. In addition, we required the Jeans solutions to satisfy regular boundary conditions both at the center (finite pressure, round gravitational potential) and on the outskirts (finite overall mass). With these building blocks, we derived physical solutions, dubbed "α-profiles". We find the one with α = 1.25, suitable for the Galaxy halo, to be intrinsically flatter at the center than the empirical NFW formula, yet steeper than the empirical Einasto profile. On scales of 10 −1 deg it yields annihilation fluxes lower by a factor 5 than the former, yet higher by a factor 10 than the latter. Such fluxes will eventually fall within the reach of the Fermi satellite. We show the effectiveness of the α-profile in relieving the astrophysical uncertainties related to the macroscopic DM distribution, and discuss its expected performance as a tool instrumental in interpreting the upcoming γ-ray data in terms of DM annihilation.

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The growth and structure of dark matter haloes

Cited by 336 publications

References 28 publications

The origin of cold dark matter halo density profiles

The origin of cold dark matter halo density profiles

Formation of disc galaxies in preheated media: a preventative feedback model

Gamma rays from annihilations at the galactic center in a physical dark matter distribution

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