Galaxy clusters and cold dark matter - A low-density unbiased universe?

1992 ◽  
Vol 398 ◽  
pp. L81 ◽  
Author(s):  
Neta A. Bahcall ◽  
Renyue Cen
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Cold Dark Matter ◽  
Low Density

scholarly journals Understanding the large inferred Einstein radii of observed low-mass galaxy clusters

2020 ◽  
Vol 494 (4) ◽  
pp. 4706-4712 ◽  
Author(s):  
Andrew Robertson ◽  
Richard Massey ◽  
Vincent Eke
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Baryonic Matter ◽  
Analysis Method ◽  
Critical Curves ◽  
Hydrodynamical Simulation ◽  
Low Mass ◽  
Main Effects

ABSTRACT We assess a claim that observed galaxy clusters with mass ${\sim}10^{14} \mathrm{\, M_\odot }$ are more centrally concentrated than predicted in lambda cold dark matter (ΛCDM). We generate mock strong gravitational lensing observations, taking the lenses from a cosmological hydrodynamical simulation, and analyse them in the same way as the real Universe. The observed and simulated lensing arcs are consistent with one another, with three main effects responsible for the previously claimed inconsistency. First, galaxy clusters containing baryonic matter have higher central densities than their counterparts simulated with only dark matter. Secondly, a sample of clusters selected because of the presence of pronounced gravitational lensing arcs preferentially finds centrally concentrated clusters with large Einstein radii. Thirdly, lensed arcs are usually straighter than critical curves, and the chosen image analysis method (fitting circles through the arcs) overestimates the Einstein radii. After accounting for these three effects, ΛCDM predicts that galaxy clusters should produce giant lensing arcs that match those in the observed Universe.

scholarly journals The Dark Matter Distribution in the Central Regions of Galaxy Clusters: Implications for Cold Dark Matter

2004 ◽  
Vol 604 (1) ◽  
pp. 88-107 ◽  
Author(s):  
David J. Sand ◽  
Tommaso Treu ◽  
Graham P. Smith ◽  
Richard S. Ellis
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Cold Dark Matter ◽  
Matter Distribution ◽  
Central Regions ◽  
Dark Matter Distribution

scholarly journals Observable tests of self-interacting dark matter in galaxy clusters: BCG wobbles in a constant density core

2019 ◽  
Vol 488 (2) ◽  
pp. 1572-1579 ◽  
Author(s):  
David Harvey ◽  
Andrew Robertson ◽  
Richard Massey ◽  
Ian G McCarthy
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Cross Section ◽  
Cross Sections ◽  
Cold Dark Matter ◽  
Dwarf Galaxies ◽  
Constant Density ◽  
Cluster Galaxy ◽  
Imaging Telescope ◽  
Observed Behaviour

ABSTRACT Models of cold dark matter (CDM) predict that the distribution of dark matter in galaxy clusters should be cuspy, centrally concentrated. Constant density cores would be strong evidence for beyond CDM physics, such as self-interacting dark matter (SIDM). An observable consequence would be oscillations of the brightest cluster galaxy (BCG) in otherwise relaxed galaxy clusters. Offset BCGs have indeed been observed – but only interpreted via a simplified, analytic model of oscillations. We compare these observations to the BAryons and HAloes of MAssive Sysmtes (BAHAMAS)–SIDM suite of cosmological simulations, which include SIDM and a fully hydrodynamical treatment of star formation and feedback. We predict that the median offset of BCGs increases with the SIDM cross-section, cluster mass, and the amount of stellar mass within 10 kpc, while CDM exhibits no trend in mass. Interpolating between the simulated cross-sections, we find that the observations (of 10 clusters) are consistent with CDM at the ∼1.5σ level, and prefer cross-section σ/m < 0.12(0.39) cm2 g−1 at 68 per cent (95 per cent) confidence level. This is on the verge of ruling out velocity-independent dark matter self-interactions as the solution to discrepancies between the predicted and observed behaviour of dwarf galaxies, and will be improved by larger surveys by Euclid or Super-pressure Balloon-borne Imaging Telescope (SuperBIT).

scholarly journals Testing Modified Dark Matter with galaxy clusters: Does dark matter know about the cosmological constant?

2017 ◽  
Vol 32 (18) ◽  
pp. 1750108 ◽  
Author(s):  
Douglas Edmonds ◽  
Duncan Farrah ◽  
Chiu Man Ho ◽  
Djordje Minic ◽  
Y. Jack Ng ◽  
...  
Keyword(s):  
Dark Matter ◽  
Cosmological Constant ◽  
Galaxy Clusters ◽  
Cold Dark Matter ◽  
Galactic Rotation ◽  
Dark Matter Mass ◽  
Mass Profile ◽  
The One ◽  
Gravitational Thermodynamics ◽  
Mass Profiles

We discuss the possibility that the cold dark matter mass profiles contain information on the cosmological constant [Formula: see text], and that such information constrains the nature of cold dark matter (CDM). We call this approach Modified Dark Matter (MDM). In particular, we examine the ability of MDM to explain the observed mass profiles of 13 galaxy clusters. Using general arguments from gravitational thermodynamics, we provide a theoretical justification for our MDM mass profile. In order to properly fit the shape of the mass profiles in galaxy clusters, we find it necessary to generalize the MDM mass profile from the one we used previously to fit galactic rotation curves. We successfully compare it to the NFW mass profiles both on cluster and galactic scales, though differences in form appear with the change in scales. Our results suggest that indeed the CDM mass profiles contain information about the cosmological constant in a nontrivial way.

scholarly journals Clustering of galaxy clusters in cold dark matter universes

2002 ◽  
Vol 319 (1) ◽  
pp. 209-214 ◽  
Author(s):  
J. M. Colberg ◽  
S. D. M. White ◽  
N. Yoshida ◽  
T. J. MacFarland ◽  
A. Jenkins ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Cold Dark Matter

scholarly journals Dark matter, dark energy and fundamental acceleration

2020 ◽  
Vol 29 (14) ◽  
pp. 2043030
Author(s):  
Douglas Edmonds ◽  
Djordje Minic ◽  
Tatsu Takeuchi
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Numerical Simulations ◽  
Structure Formation ◽  
Galaxy Clusters ◽  
Cold Dark Matter ◽  
Length Scales ◽  
Astrophysical Objects

We discuss the existence of an acceleration scale in galaxies and galaxy clusters and its relevance for the nature of dark matter. The presence of the same acceleration scale found at very different length scales, and in very different astrophysical objects, strongly supports the existence of a fundamental acceleration scale governing the observed gravitational physics. We comment on the implications of such a fundamental acceleration scale for constraining cold dark matter models as well as its relevance for structure formation to be explored in future numerical simulations.

scholarly journals An excess of small-scale gravitational lenses observed in galaxy clusters

Science ◽  
2020 ◽  
Vol 369 (6509) ◽  
pp. 1347-1351 ◽  
Author(s):  
Massimo Meneghetti ◽  
Guido Davoli ◽  
Pietro Bergamini ◽  
Piero Rosati ◽  
Priyamvada Natarajan ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
Small Scale ◽  
Gravitational Lenses ◽  
Strong Lensing ◽  
Luminous Matter ◽  
Order Of Magnitude ◽  
The Universe

Cold dark matter (CDM) constitutes most of the matter in the Universe. The interplay between dark and luminous matter in dense cosmic environments, such as galaxy clusters, is studied theoretically using cosmological simulations. Observations of gravitational lensing are used to characterize the properties of substructures—the small-scale distribution of dark matter—in clusters. We derive a metric, the probability of strong lensing events produced by dark-matter substructure, and compute it for 11 galaxy clusters. The observed cluster substructures are more efficient lenses than predicted by CDM simulations, by more than an order of magnitude. We suggest that systematic issues with simulations or incorrect assumptions about the properties of dark matter could explain our results.

scholarly journals Constraining the cross-section of dark matter with giant radial arcs in galaxy clusters

2020 ◽  
Vol 500 (1) ◽  
pp. 247-258
Author(s):  
J Vega-Ferrero ◽  
J M Dana ◽  
J M Diego ◽  
G Yepes ◽  
W Cui ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Cross Section ◽  
Central Region ◽  
Cold Dark Matter ◽  
The Other ◽  
Negligible Probability ◽  
Major Merger ◽  
Model Versus ◽  
Better Than

ABSTRACT We compare the statistics and morphology of giant arcs in galaxy clusters using N-body and non-radiative SPH simulations within the standard cold dark matter (CDM) model and simulations where dark matter (DM) has a non-negligible probability of interaction (parametrized by its cross-section), i.e self-interacting dark matter (SIDM). We use a ray-tracing technique to produce a statistically large number of arcs around six simulated galaxy clusters at different redshifts. Since DM is more likely to interact in colliding clusters than in relaxed clusters, and this probability of interaction is largest in denser regions, we focus our analysis on radial arcs (which trace the lensing potential in the central region better than tangential arcs) in galaxy clusters that underwent (or are undergoing) a major merger. We find that SIDM produces fewer radial arcs than standard CDM but they are on average more magnified. We also appreciate differences in the arc morphology that could be used to statistically favour one model versus the other.

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