The Redshift Evolution of LCDM Halo Parameters

Muñoz-Cuartas, J. C.; Macciò, Andrea V.; Gottlöber, Stefan; Dutton, Aaron A.

doi:10.22323/1.121.0016

Cited by 9 publications

(17 citation statements)

References 18 publications

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“…This procedure minimizes effects of fluctuations and gives the median halo concentration for a given mass. Muñoz-Cuartas et al (2010) applied our method to their simulations and reproduced results of direct density profile fitting. Prada et al (2011) state that this method recovers results of halo concentrations c(M ) in MS-I (Neto et al 2007) with deviations of less than 5 percent over the whole range of masses in the simulation.…”

Section: Halo Mass and Concentration Functionsmentioning

confidence: 98%

Dark Matter Halos in the Standard Cosmological Model: Results From the Bolshoi Simulation

Klypin

Trujillo-Gomez

Primack

2011

ApJ

971

1,137

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Lambda Cold Dark Matter (ΛCDM) is now the standard theory of structure formation in the Universe. We present the first results from the new Bolshoi dissipationless cosmological ΛCDM simulation that uses cosmological parameters favored by current observations. The Bolshoi simulation was run in a volume 250 h −1 Mpc on a side using ∼8 billion particles with mass and force resolution adequate to follow subhalos down to the completeness limit of V circ = 50 km s −1 maximum circular velocity. Using merger trees derived from analysis of 180 stored time-steps we find the circular velocities of satellites before they fall into their host halos. Using excellent statistics of halos and subhalos (∼10 million at every moment and ∼50 million over the whole history) we present accurate approximations for statistics such as the halo mass function, the concentrations for distinct halos and subhalos, abundance of halos as a function of their circular velocity, the abundance and the spatial distribution of subhalos. We find that at high redshifts the concentration falls to a minimum value of about 4.0 and then rises for higher values of halo mass, a new result. We present approximations for the velocity and mass functions of distinct halos as a function of redshift. We find that while the Sheth-Tormen approximation for the mass function of halos found by spherical overdensity is quite accurate at low redshifts, the ST formula over-predicts the abundance of halos by nearly an order of magnitude by z = 10. We find that the number of subhalos scales with the circular velocity of the host halo as V 1/2 host , and that subhalos have nearly the same radial distribution as dark matter particles at radii 0.3-2 times the host halo virial radius. The subhalo velocity function N (> V sub ) scales as V −3 circ . Combining the results of Bolshoi and Via Lactea-II simulations, we find that inside the virial radius of halos with V circ = 200 km s −1 the number of satellites is N (> V sub ) = (V sub /58 km s −1 ) −3 for satellite circular velocities in the range 4 km s −1 < V sub < 150 km s −1 .

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Section: Halo Mass and Concentration Functionsmentioning

confidence: 98%

Dark Matter Halos in the Standard Cosmological Model: Results From the Bolshoi Simulation

Klypin

Trujillo-Gomez

Primack

2011

ApJ

971

1,137

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“…[19], with subhalo-to-subhalo variations modeled by a lognormal distribution with a dispersion of σ c = 0.24 [21].…”

Section: Dark Matter Subhalos In the Milky Waymentioning

confidence: 99%

“…As we will show, the precise value of this threshold does not significantly impact Fermi's sensitivity to dark matter annihilations in subhalos, as the constraints are dominated by the observed number of very bright sources. In generating this figure, we have adopted central values for the halo concentration [19], thus neglecting the impact of halo-to-halo variations.…”

Section: Dark Matter Subhalos In the Milky Waymentioning

confidence: 99%

Stringent constraints on the dark matter annihilation cross section from subhalo searches with the Fermi Gamma-Ray Space Telescope

Berlin

2014

Phys. Rev. D

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The dark matter halo of the Milky Way is predicted to contain a very large number of smaller subhalos. As a result of the dark matter annihilations taking place within such objects, the most nearby and massive subhalos could appear as point-like or spatially extended gamma-ray sources, without observable counterparts at other wavelengths. In this paper, we use the results of the Aquarius simulation to predict the distribution of nearby subhalos, and compare this to the characteristics of the unidentified gamma-ray sources observed by the Fermi Gamma-Ray Space Telescope. Focusing on the brightest high latitude sources, we use this comparison to derive limits on the dark matter annihilation cross section. For dark matter particles lighter than ∼200 GeV, the resulting limits are the strongest obtained to date, being modestly more stringent than those derived from observations of dwarf galaxies or the Galactic Center. We also derive independent limits based on the lack of unidentified gamma-ray sources with discernible spatial extension, but these limits are a factor of ∼2-10 weaker than those based on point-like subhalos. Lastly, we note that four of the ten brightest high-latitude sources exhibit a similar spectral shape, consistent with 30-60 GeV dark matter particles annihilating to bb with an annihilation cross section on the order of σv ∼ (5 − 10) × 10 −27 cm 3 /s, or 8-10 GeV dark matter particles annihilating to τ + τ − with σv ∼ (2.0 − 2.5) × 10 −27 cm 3 /s.

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“…To determine the concentration of a halo of a given mass and at a given redshift, c(z, M ), we use the model of Bullock et al [26] (alternatively, using the mass-concentration relationship of Ref. [27] modifies our results only slightly). We also account for halo-tohalo variations in concentration, which are taken to follow a log-normal distribution with ∆(log 10 c) = 0.2 [28].…”

Section: The Contribution From Dark Matter Annihilations To the Ementioning

confidence: 99%

The isotropic radio background and annihilating dark matter

et al. 2012

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Observations by ARCADE-2 and other telescopes sensitive to low frequency radiation have revealed the presence of an isotropic radio background with a hard spectral index. The intensity of this observed background is found to exceed the flux predicted from astrophysical sources by a factor of approximately 5-6. In this article, we consider the possibility that annihilating dark matter particles provide the primary contribution to the observed isotropic radio background through the emission of synchrotron radiation from electron and positron annihilation products. For reasonable estimates of the magnetic fields present in clusters and galaxies, we find that dark matter could potentially account for the observed radio excess, but only if it annihilates mostly to electrons and/or muons, and only if it possesses a mass in the range of approximately 5-50 GeV. For such models, the annihilation cross section required to normalize the synchrotron signal to the observed excess is σv ≈ (0.4 − 30) × 10 −26 cm 3 /s, similar to the value predicted for a simple thermal relic (σv ≈ 3 × 10 −26 cm 3 /s). We find that in any scenario in which dark matter annihilations are responsible for the observed excess radio emission, a significant fraction of the isotropic gamma ray background observed by Fermi must result from dark matter as well.

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The Redshift Evolution of LCDM Halo Parameters

Cited by 9 publications

References 18 publications

Dark Matter Halos in the Standard Cosmological Model: Results From the Bolshoi Simulation

Dark Matter Halos in the Standard Cosmological Model: Results From the Bolshoi Simulation

Stringent constraints on the dark matter annihilation cross section from subhalo searches with the Fermi Gamma-Ray Space Telescope

The isotropic radio background and annihilating dark matter

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