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 Decomposition of the Visible and Dark Matter Mass Profiles in the Einstein Ring 0047–2808

2004 ◽  
Vol 220 ◽  
pp. 115-120
Author(s):  
Simon Dye ◽  
Steve Warren
Keyword(s):  
Dark Matter ◽  
Information Content ◽  
Linear Method ◽  
Ring System ◽  
Inversion Method ◽  
Linear Inversion ◽  
Dark Matter Mass ◽  
Mass Profile ◽  
Einstein Radius ◽  
Mass Profiles

Using our semi-linear inversion method, we measure the mass profile of the lens galaxy in the Einstein ring system 0047–2808. The lens is modeled as a baryonic component following the observed light embedded in a generalised dark matter NFW halo. The semi-linear method makes full use of the information content in the ring image. We determine a B-band mass to light ratio for the baryons of 2.33+0.30–0.62h M⊙/LB⊙ (99% CL), accounting for 54% of the total projected mass within the Einstein radius of 1.16″. The inner logarithmic slope of the halo is found to be 0.65+0.73–0.31 (99% CL). We find that the halo is fairly well aligned with the light but has only half the ellipticity.

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 Local group star formation in warm and self-interacting dark matter cosmologies

2020 ◽  
Vol 498 (1) ◽  
pp. 702-717 ◽  
Author(s):  
Mark R Lovell ◽  
Wojciech Hellwing ◽  
Aaron Ludlow ◽  
Jesús Zavala ◽  
Andrew Robertson ◽  
...  
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Local Group ◽  
Initial Density ◽  
Dark Matter Mass ◽  
Stellar Ages ◽  
Hydrodynamical Simulations ◽  
Star Formation Histories

ABSTRACT The nature of the dark matter can affect the collapse time of dark matter haloes, and can therefore be imprinted in observables such as the stellar population ages and star formation histories of dwarf galaxies. In this paper, we use high-resolution hydrodynamical simulations of Local Group-analogue (LG) volumes in cold dark matter (CDM), sterile neutrino warm dark matter (WDM) and self-interacting dark matter (SIDM) models with the eagle galaxy formation code to study how galaxy formation times change with dark matter model. We are able to identify the same haloes in different simulations, since they share the same initial density field phases. We find that the stellar mass of galaxies depends systematically on resolution, and can differ by as much as a factor of 2 in haloes of a given dark matter mass. The evolution of the stellar populations in SIDM is largely identical to that of CDM, but in WDM early star formation is instead suppressed. The time at which LG haloes can begin to form stars through atomic cooling is delayed by ∼200 Myr in WDM models compared to CDM. It will be necessary to measure stellar ages of old populations to a precision of better than 100 Myr, and to address degeneracies with the redshift of reionization – and potentially other baryonic processes – in order to use these observables to distinguish between dark matter models.

scholarly journals Supernovae Blast Waves in Proto-Dwarf Galaxies

1988 ◽  
Vol 101 ◽  
pp. 513-520
Author(s):  
Alberto Noriego-Crespo ◽  
Peter Bodenheimer
Keyword(s):  
Dark Matter ◽  
Mass Loss ◽  
Gravitational Potential ◽  
Cold Dark Matter ◽  
First Generation ◽  
Dwarf Galaxies ◽  
Blast Waves ◽  
The One

AbstractGas mass loss in proto-dwarf galaxies can be efficiently driven out by blast waves created by the first generation of supernovae. There is, however, a threshold set by the total gravitational potential beyond which gas mass loss does not occur. This limit is in agreement with the one predicted by some Cold Dark Matter senarios.

scholarly journals Gamma-Ray Sensitivity to Dark Matter Subhalo Modelling at High Latitudes

Galaxies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 90 ◽  
Author(s):  
Francesca Calore ◽  
Moritz Hütten ◽  
Martin Stref
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Detection Threshold ◽  
Point Sources ◽  
Large Set ◽  
Case Scenario ◽  
Tidal Disruption ◽  
Dwarf Spheroidal Galaxies ◽  
Dark Matter Mass ◽  
The One

Searches for “dark” subhaloes in gamma-ray point-like source catalogues are among promising strategies for indirect dark matter detection. Such a search is nevertheless affected by uncertainties related, on the one hand, to the modelling of the dark matter subhalo distribution in Milky-Way-like galaxies, and, on the other hand, to the sensitivity of gamma-ray instruments to the dark matter subhalo signals. In the present work, we assess the detectability of dark matter subhaloes in Fermi-LAT catalogues, taking into accounts uncertainties associated with the modelling of the galactic subhalo population. We use four different halo models bracketing a large set of uncertainties. For each model, adopting an accurate detection threshold of the LAT to dark matter subhalo signals and comparing model predictions with the number of unassociated point-sources in Fermi-LAT catalogues, we derive upper limits on the annihilation cross section as a function of dark matter mass. Our results show that, even in the best-case scenario (i.e., DMonly subhalo model), which does not include tidal disruption from baryons, the limits on the dark matter parameter space are less stringent than current gamma-ray limits from dwarf spheroidal galaxies. Comparing the results obtained with the different subhalo models, we find that baryonic effects on the subhalo population are significant and lead to dark matter constraints that are less stringent by a factor of ∼2 to ∼5. This uncertainty comes from the unknown resilience of dark matter subhaloes to tidal disruption.

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