The spatial correlation properties of galaxy halos in a cold dark matter universe

1992 ◽  
Vol 400 ◽  
pp. 398 ◽  
Author(s):  
T. G. Brainerd ◽  
J. V. Villumsen
Keyword(s):  
Dark Matter ◽  
Spatial Correlation ◽  
Cold Dark Matter ◽  
Galaxy Halos ◽  
Correlation Properties

scholarly journals N-Body Results on Dark Matter

1987 ◽  
Vol 117 ◽  
pp. 263-278
Author(s):  
Simon D. M. White
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Cold Dark Matter ◽  
Density Fluctuations ◽  
Major Difficulty ◽  
Mass Distributions ◽  
Galaxy Distribution ◽  
Galaxy Halos ◽  
Flat Rotation Curves ◽  
The Universe

The structure of the dominant “dark” component of the Universe may evolve primarily under the influence of gravity. A number of models for the evolution of the Universe make specific predictions for the statistical properties of density fluctuations at early times. N-body simulations can follow the nonlinear development of such fluctuations to the present day. A major difficulty arises because we cannot observe the present mass distribution directly. Recent N-body work has concentrated on models dominated by weakly interacting free elementary particles. Neutrino-dominated but otherwise conventional cosmologies pass rapidly from a smooth distribution to one dominated by lumps with masses greater than those of any known object. Cosmologies dominated by “cold dark matter” produce mass distributions which fit the observed galaxy distribution (i) if Ω = 0.1–0.2 and galaxies follow the mass distribution, or (ii) if Ω = 1, HO< 50 km/s/Mpc and galaxies form preferentially in high density regions. In the latter case, clumps form with flat rotation curves with about the amplitude and abundance expected for galaxy halos.

The mass function of galaxy halos in a cold dark matter universe

1992 ◽  
Vol 394 ◽  
pp. 409 ◽  
Author(s):  
T. G. Brainerd ◽  
J. V. Villumsen
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Mass Function ◽  
Galaxy Halos

scholarly journals Correlation function: biasing and fractal properties of the cosmic web

2020 ◽  
Vol 640 ◽  
pp. A47 ◽  
Author(s):  
J. Einasto ◽  
G. Hütsi ◽  
T. Kuutma ◽  
M. Einasto
Keyword(s):  
Dark Matter ◽  
Correlation Function ◽  
Fractal Dimension ◽  
Spatial Correlation ◽  
Correlation Functions ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Density Field ◽  
Bias Parameter ◽  
Fractal Properties

Aims. Our goal is to determine how the spatial correlation function of galaxies describes biasing and fractal properties of the cosmic web. Methods. We calculated spatial correlation functions of galaxies, ξ(r), structure functions, g(r) = 1 + ξ(r), gradient functions, γ(r) = d log g(r)/d log r, and fractal dimension functions, D(r) = 3 + γ(r), using dark matter particles of the biased Λ cold dark matter (CDM) simulation, observed galaxies of the Sloan Digital Sky Survey (SDSS), and simulated galaxies of the Millennium and EAGLE simulations. We analysed how these functions describe fractal and biasing properties of the cosmic web. Results. The correlation functions of the biased ΛCDM model samples at small distances (particle and galaxy separations), r ≤ 2.25 h−1 Mpc, describe the distribution of matter inside dark matter halos. In real and simulated galaxy samples, only the brightest galaxies in clusters are visible, and the transition from clusters to filaments occurs at a distance r ≈ 0.8−1.5 h−1 Mpc. At larger separations, the correlation functions describe the distribution of matter and galaxies in the whole cosmic web. The effective fractal dimension of the cosmic web is a continuous function of the distance (separation). Real and simulated galaxies of low luminosity, Mr ≥ −19, have almost identical correlation lengths and amplitudes, indicating that dwarf galaxies are satellites of brighter galaxies, and do not form a smooth population in voids. Conclusions. The combination of several physical processes (e.g. the formation of halos along the caustics of particle trajectories and the phase synchronisation of density perturbations on various scales) transforms the initial random density field to the current highly non-random density field. Galaxy formation is suppressed in voids, which increases the amplitudes of correlation functions and power spectra of galaxies, and increases the large-scale bias parameter. The combined evidence leads to the large-scale bias parameter of L⋆ galaxies the value b⋆ = 1.85 ± 0.15. We find r0(L⋆) = 7.20 ± 0.19 for the correlation length of L⋆ galaxies.

scholarly journals COLD DARK MATTER SUBSTRUCTURES IN EARLY-TYPE GALAXY HALOS

2016 ◽  
Vol 824 (2) ◽  
pp. 144 ◽  
Author(s):  
Davide Fiacconi ◽  
Piero Madau ◽  
Doug Potter ◽  
Joachim Stadel
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Early Type ◽  
Galaxy Halos ◽  
Early Type Galaxy

scholarly journals Halo formation and evolution: unification of structure and physical properties

2015 ◽  
Vol 11 (S317) ◽  
pp. 298-299
Author(s):  
Allan D. Ernest ◽  
Matthew P. Collins
Keyword(s):  
Dark Matter ◽  
Globular Clusters ◽  
Cold Dark Matter ◽  
Weakly Interacting Massive Particles ◽  
Dark Matter Halo ◽  
Microwave Background ◽  
Dwarf Spheroidal Galaxies ◽  
Hot Gas ◽  
Galaxy Halos ◽  
Formation And Evolution

AbstractThe assembly of matter in the universe proliferates a wide variety of halo structures, often with enigmatic consequences. Giant spiral galaxies, for example, contain both dark matter and hot gas, while dwarf spheroidal galaxies, with weaker gravity, contain much larger fractions of dark matter, but little gas. Globular clusters, superficially resembling these dwarf spheroidals, have little or no dark matter. Halo temperatures are also puzzling: hot cluster halos contain cooler galaxy halos; dwarf galaxies have no hot gas at all despite their similar internal processes. Another mystery is the origin of the gas that galaxies require to maintain their measured star formation rates (SFRs). We outline how gravitational quantum theory solves these problems, and enables baryons to function as weakly-interacting-massive-particles (WIMPs) in Lambda Cold Dark Matter (LCDM) theory. Significantly, these dark-baryon ensembles may also be consistent with primordial nucleosynthesis (BBN) and cosmic microwave background (CMB) anisotropies.

Bolometric Detection of Cold Dark Matter Candidates

1988 ◽  
Author(s):  
A. K. Drukier ◽  
Katherine Freese ◽  
Joshua Frieman
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Bolometric Detection

scholarly journals Detecting Cold Dark Matter Candidates

1987 ◽  
Vol 117 ◽  
pp. 490-490
Author(s):  
A. K. Drukier ◽  
K. Freese ◽  
D. N. Spergel
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Galactic Halo ◽  
Dark Matter Particle ◽  
Low Energy ◽  
The Sun ◽  
Background Rate ◽  
System Noise ◽  
Weakly Interacting ◽  
Massive Neutrinos

We consider the use of superheated superconducting colloids as detectors of weakly interacting galactic halo candidate particles (e.g. photinos, massive neutrinos, and scalar neutrinos). These low temperature detectors are sensitive to the deposition of a few hundreds of eV's. The recoil of a dark matter particle off of a superheated superconducting grain in the detector causes the grain to make a transition to the normal state. Their low energy threshold makes this class of detectors ideal for detecting massive weakly interacting halo particles.We discuss realistic models for the detector and for the galactic halo. We show that the expected count rate (≈103 count/day for scalar and massive neutrinos) exceeds the expected background by several orders of magnitude. For photinos, we expect ≈1 count/day, more than 100 times the predicted background rate. We find that if the detector temperature is maintained at 50 mK and the system noise is reduced below 5 × 10−4 flux quanta, particles with mass as low as 2 GeV can be detected. We show that the earth's motion around the Sun can produce a significant annual modulation in the signal.

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