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

The Expected Mass Function for Low‐Mass Galaxies in a Cold Dark Matter Cosmology: Is There a Problem?

2001 ◽  
Vol 563 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Weihsueh A. Chiu ◽  
Nickolay Y. Gnedin ◽  
Jeremiah P. Ostriker
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Mass Function ◽  
Low Mass

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.

scholarly journals The lensing properties of subhaloes in massive elliptical galaxies in sterile neutrino cosmologies

2019 ◽  
Vol 491 (1) ◽  
pp. 1295-1310 ◽  
Author(s):  
Giulia Despali ◽  
Mark Lovell ◽  
Simona Vegetti ◽  
Robert A Crain ◽  
Benjamin D Oppenheimer
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Distribution Density ◽  
Sterile Neutrino ◽  
Power Spectra ◽  
Mass Function ◽  
Elliptical Galaxies ◽  
Hydrodynamical Simulations

ABSTRACT We use high-resolution hydrodynamical simulations run with the EAGLE model of galaxy formation to study the differences between the properties of – and subsequently the lensing signal from – subhaloes of massive elliptical galaxies at redshift 0.2, in Cold and Sterile Neutrino (SN) Dark Matter models. We focus on the two 7 keV SN models that bracket the range of matter power spectra compatible with resonantly produced SN as the source of the observed 3.5 keV line. We derive an accurate parametrization for the subhalo mass function in these two SN models relative to cold dark matter (CDM), as well as the subhalo spatial distribution, density profile, and projected number density and the dark matter fraction in subhaloes. We create mock lensing maps from the simulated haloes to study the differences in the lensing signal in the framework of subhalo detection. We find that subhalo convergence is well described by a lognormal distribution and that signal of subhaloes in the power spectrum is lower in SN models with respect to CDM, at a level of 10–80 per cent, depending on the scale. However, the scatter between different projections is large and might make the use of power spectrum studies on the typical scales of current lensing images very difficult. Moreover, in the framework of individual detections through gravitational imaging a sample of ≃30 lenses with an average sensitivity of $M_{\rm {sub}} = 5 \times 10^{7}\, {\rm M}_{\odot}$ would be required to discriminate between CDM and the considered sterile neutrino models.

scholarly journals Clues to the nature of dark matter from first galaxies

2019 ◽  
Vol 489 (1) ◽  
pp. 487-496 ◽  
Author(s):  
Boyan K Stoychev ◽  
Keri L Dixon ◽  
Andrea V Macciò ◽  
Marvin Blank ◽  
Aaron A Dutton
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Formation Rate ◽  
Neutral Hydrogen ◽  
Mass Function ◽  
Stellar Mass ◽  
The Impact

ABSTRACT We use 38 high-resolution simulations of galaxy formation between redshift 10 and 5 to study the impact of a 3 keV warm dark matter (WDM) candidate on the high-redshift Universe. We focus our attention on the stellar mass function and the global star formation rate and consider the consequences for reionization, namely the neutral hydrogen fraction evolution and the electron scattering optical depth. We find that three different effects contribute to differentiate warm and cold dark matter (CDM) predictions: WDM suppresses the number of haloes with mass less than few 109 M⊙; at a fixed halo mass, WDM produces fewer stars than CDM, and finally at halo masses below 109 M⊙, WDM has a larger fraction of dark haloes than CDM post-reionization. These three effects combine to produce a lower stellar mass function in WDM for galaxies with stellar masses at and below 107 M⊙. For z > 7, the global star formation density is lower by a factor of two in the WDM scenario, and for a fixed escape fraction, the fraction of neutral hydrogen is higher by 0.3 at z ∼ 6. This latter quantity can be partially reconciled with CDM and observations only by increasing the escape fraction from 23 per cent to 34 per cent. Overall, our study shows that galaxy formation simulations at high redshift are a key tool to differentiate between dark matter candidates given a model for baryonic physics.

scholarly journals Galaxy Formation in a Universe Dominated by Cold Dark Matter

1987 ◽  
Vol 117 ◽  
pp. 360-360
Author(s):  
Edmund Bertschinger
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Globular Clusters ◽  
Cold Dark Matter ◽  
Mass Function ◽  
Spherical Approximation ◽  
De Sitter ◽  
Density Peaks ◽  
Lower Amplitude ◽  
Baryonic Mass

ABSTRACT The mass spectrum of bound baryonic systems (galaxies and globular clusters) is computed as a function of redshift in an Einstein-de Sitter (Ω=1) universe dominated by weakly interacting, cold dark matter. Baryons are assumed to fall into primordial density peaks in the cold particle distribution when the mass in the peaks exceeds the baryon Jeans mass. The distribution of peaks is computed using Gaussian statistics. As the universe expands the baryonic mass attached to a given peak increases because of infall (treated in a spherical approximation), and new peaks of lower amplitude become nonlinear. Globular clusters form first (by z∼40 if the galaxies represent a biased mass distribution). The remaining gas may be reheated to ∼10000 K if a few percent of globular cluster (or Pop. III) stars are very massive. Reheating increases the baryon Jeans mass and delays galaxy formation until z≲10. The present method reproduces the shape (but not the amplitude) of the Schechter galaxy mass function when merging of substructure is included in an approximate fashion.

scholarly journals The normalization and slope of the dark matter (sub-)halo mass function on sub-galactic scales

2020 ◽  
Vol 493 (1) ◽  
pp. 1268-1276
Author(s):  
Andrew J Benson
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Mass Range ◽  
Mass Function ◽  
Matter Content ◽  
Dark Matter Halo ◽  
Halo Masses ◽  
Near Future ◽  
Mass Functions

ABSTRACT Simulations of cold dark matter make robust predictions about the slope and normalization of the dark matter halo and subhalo mass functions on small scales. Recent observational advances utilizing strong gravitational lensing have demonstrated the ability of this technique to place constraints on these quantities on subgalactic scales corresponding to dark matter halo masses of 106–$10^9\, \mathrm{M}_\odot$. On these scales the physics of baryons, which make up around 17 per cent of the matter content of the Universe but which are not included in pure dark matter N-body simulations, are expected to affect the growth of structure and the collapse of dark matter haloes. In this work, we develop a semi-analytic model to predict the amplitude and slope of the dark matter halo and subhalo mass functions on subgalactic scales in the presence of baryons. We find that the halo mass function is suppressed by up to 25 per cent, and the slope is modified, ranging from −1.916 to −1.868 in this mass range. These results are consistent with current measurements, but differ sufficiently from the expectations for a dark matter only universe that it may be testable in the near future.

scholarly journals Modelling the Effects of Dark Matter Substructure on Globular Cluster Evolution with the Tidal Approximation

2019 ◽  
Author(s):  
Jeremy J Webb ◽  
Jo Bovy ◽  
Raymond G Carlberg ◽  
Mark Gieles
Keyword(s):  
Dark Matter ◽  
Cold Dark Matter ◽  
Star Clusters ◽  
Mass Function ◽  
Model Cluster ◽  
Cluster Evolution ◽  
Mass Size ◽  
Low Mass ◽  
Tidal Heating ◽  
Size Relation

Abstract We present direct N-body simulations of tidally filling 30,000 M⊙ star clusters orbiting between 10 kpc and 100 kpc in galaxies with a range of dark matter substructure properties. The time-dependent tidal force is determined based on the combined tidal tensor of the galaxy’s smooth and clumpy dark matter components, the latter of which causes fluctuations in the tidal field that can heat clusters. The strength and duration of these fluctuations are sensitive to the local dark matter density, substructure fraction, sub-halo mass function, and the sub-halo mass-size relation. Based on the cold dark matter framework, we initially assume sub-halos are Hernquist spheres following a power-law mass function between 105 and 1011M⊙ and find that tidal fluctuations are too weak and too short to affect star cluster evolution. Treating sub-halos as point masses, to explore how denser sub-halos affect clusters, we find that only sub-halos with masses greater than 106M⊙ will cause cluster dissolution times to decrease. These interactions can also decrease the size of a cluster while increasing the velocity dispersion and tangential anisotropy in the outer regions via tidal heating. Hence increased fluctuations in the tidal tensor, especially fluctuations that are due to low-mass halos, do not necessarily translate into mass loss. We further conclude that the tidal approximation can be used to model cluster evolution in the tidal fields of cosmological simulations with a minimum cold dark matter sub-halo mass of 106M⊙, as the effect of lower-mass sub-halos on star clusters is negligible.

scholarly journals LARGE SCALE STRUCTURE BY GLOBAL MONOPOLES AND COLD DARK MATTER

1992 ◽  
Vol 07 (10) ◽  
pp. 903-910 ◽  
Author(s):  
LEANDROS PERIVOLAROPOULOS
Keyword(s):  
Dark Matter ◽  
Cosmological Model ◽  
Gravitational Wave ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Mass Range ◽  
Large Scale Structure ◽  
Mass Function ◽  
Global Monopoles ◽  
Good Agreement

A cosmological model in which the primordial perturbations are provided by global monopoles and in which the dark matter is cold has several interesting features. The model is normalized by choosing its single parameter within the bounds obtained from gravitational wave constraints and by demanding coherent velocity flows of about 600 km/sec on scales of 50h-1 Mpc . Using this normalization, the model predicts the existence of dominant structures with mass 2×1016M⊙ on a scale 35h-1 Mpc , i.e., larger than the horizon at t ep . The magnitude of the predicted mass function in the galactic mass range is in good agreement with the observed Schechter function.

scholarly journals Warm dark matter chills out: constraints on the halo mass function and the free-streaming length of dark matter with eight quadruple-image strong gravitational lenses

2019 ◽  
Vol 491 (4) ◽  
pp. 6077-6101 ◽  
Author(s):  
Daniel Gilman ◽  
Simon Birrer ◽  
Anna Nierenberg ◽  
Tommaso Treu ◽  
Xiaolong Du ◽  
...  
Keyword(s):  
Dark Matter ◽  
Mass Fraction ◽  
Mass Concentration ◽  
Cold Dark Matter ◽  
Finite Size ◽  
Mass Function ◽  
Line Of Sight ◽  
Gravitational Lenses ◽  
Likelihood Ratios ◽  
Mass Profile

ABSTRACT The free-streaming length of dark matter depends on fundamental dark matter physics, and determines the abundance and concentration of dark matter haloes on sub-galactic scales. Using the image positions and flux ratios from eight quadruply imaged quasars, we constrain the free-streaming length of dark matter and the amplitude of the subhalo mass function (SHMF). We model both main deflector subhaloes and haloes along the line of sight, and account for warm dark matter free-streaming effects on the mass function and mass–concentration relation. By calibrating the scaling of the SHMF with host halo mass and redshift using a suite of simulated haloes, we infer a global normalization for the SHMF. We account for finite-size background sources, and marginalize over the mass profile of the main deflector. Parametrizing dark matter free-streaming through the half-mode mass mhm, we constrain the thermal relic particle mass mDM corresponding to mhm. At $95 \, {\rm per\, cent}$ CI: mhm &lt; 107.8 M⊙ ($m_{\rm {DM}} \gt 5.2 \ \rm {keV}$). We disfavour $m_{\rm {DM}} = 4.0 \,\rm {keV}$ and $m_{\rm {DM}} = 3.0 \,\rm {keV}$ with likelihood ratios of 7:1 and 30:1, respectively, relative to the peak of the posterior distribution. Assuming cold dark matter, we constrain the projected mass in substructure between 106 and 109 M⊙ near lensed images. At $68 \, {\rm per\, cent}$ CI, we infer $2.0{-}6.1 \times 10^{7}\, {{\rm M}_{\odot }}\,\rm {kpc^{-2}}$, corresponding to mean projected mass fraction $\bar{f}_{\rm {sub}} = 0.035_{-0.017}^{+0.021}$. At $95 \, {\rm per\, cent}$ CI, we obtain a lower bound on the projected mass of $0.6 \times 10^{7} \,{{\rm M}_{\odot }}\,\rm {kpc^{-2}}$, corresponding to $\bar{f}_{\rm {sub}} \gt 0.005$. These results agree with the predictions of cold dark matter.

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