scholarly journals Sterile neutrino fits to dark matter mass profiles in the Milky Way and in galaxy clusters

2013 ◽  
Vol 349 (1) ◽  
pp. 407-413 ◽  
Author(s):  
Man Ho Chan ◽  
Robert Ehrlich
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Milky Way ◽  
Sterile Neutrino ◽  
Dark Matter Mass ◽  
Mass Profiles

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 Restrictions on parameters of sterile neutrino dark matter from observations of galaxy clusters

2006 ◽  
Vol 74 (10) ◽  
Author(s):  
A. Boyarsky ◽  
A. Neronov ◽  
O. Ruchayskiy ◽  
M. Shaposhnikov
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Sterile Neutrino

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 Constraining the inner density slope of massive galaxy clusters

2020 ◽  
Vol 496 (4) ◽  
pp. 4717-4733 ◽  
Author(s):  
Qiuhan He ◽  
Hongyu Li ◽  
Ran Li ◽  
Carlos S Frenk ◽  
Matthieu Schaller ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Matter Density ◽  
Stellar Kinematics ◽  
Density Profiles ◽  
Mass Distributions ◽  
Dark Matter Density ◽  
Dark Matter Mass ◽  
Massive Galaxy

ABSTRACT We determine the inner density profiles of massive galaxy clusters (M200 > 5 × 1014 M⊙) in the Cluster-EAGLE (C-EAGLE) hydrodynamic simulations, and investigate whether the dark matter density profiles can be correctly estimated from a combination of mock stellar kinematical and gravitational lensing data. From fitting mock stellar kinematics and lensing data generated from the simulations, we find that the inner density slopes of both the total and the dark matter mass distributions can be inferred reasonably well. We compare the density slopes of C-EAGLE clusters with those derived by Newman et al. for seven massive galaxy clusters in the local Universe. We find that the asymptotic best-fitting inner slopes of ‘generalized’ Navarro–Frenk–White (gNFW) profiles, γgNFW, of the dark matter haloes of the C-EAGLE clusters are significantly steeper than those inferred by Newman et al. However, the mean mass-weighted dark matter density slopes of the simulated clusters are in good agreement with the Newman et al. estimates. We also find that the estimate of γgNFW is very sensitive to the constraints from weak lensing measurements in the outer parts of the cluster and a bias can lead to an underestimate of γgNFW.

scholarly journals The XMM Cluster Survey: new evidence for the 3.5-keV feature in clusters is inconsistent with a dark matter origin

2020 ◽  
Vol 497 (1) ◽  
pp. 656-671 ◽  
Author(s):  
S Bhargava ◽  
P A Giles ◽  
A K Romer ◽  
T Jeltema ◽  
J Mayers ◽  
...  
Keyword(s):  
Dark Matter ◽  
Emission Line ◽  
Galaxy Clusters ◽  
Sterile Neutrino ◽  
Significant Excess ◽  
Mixing Angle ◽  
X Ray ◽  
Cluster Survey ◽  
Upper Limit ◽  
New Evidence

ABSTRACT There have been several reports of a detection of an unexplained excess of X-ray emission at $\simeq$3.5 keV in astrophysical systems. One interpretation of this excess is the decay of sterile neutrino dark matter. The most influential study to date analysed 73 clusters observed by the XMM–Newton satellite. We explore evidence for a ≃3.5-keV excess in the XMM-PN spectra of 117 redMaPPer galaxy clusters (0.1 < z < 0.6). In our analysis of individual spectra, we identify three systems with an excess of flux at $\simeq$3.5 keV. In one case (XCS J0003.3+0204), this excess may result from a discrete emission line. None of these systems are the most dark matter dominated in our sample. We group the remaining 114 clusters into four temperature (TX) bins to search for an increase in ≃3.5-keV flux excess with TX – a reliable tracer of halo mass. However, we do not find evidence of a significant excess in flux at ≃3.5 keV in any TX bins. To maximize sensitivity to a potentially weak dark matter decay feature at ≃3.5 keV, we jointly fit 114 clusters. Again, no significant excess is found at ≃3.5 keV. We estimate the upper limit of an undetected emission line at ≃3.5 keV to be 2.41 × 10−6 photons cm−2 s−1, corresponding to a mixing angle of sin 2(2θ) = 4.4 × 10−11, lower than previous estimates from cluster studies. We conclude that a flux excess at ≃3.5 keV is not a ubiquitous feature in clusters and therefore unlikely to originate from sterile neutrino dark matter decay.

scholarly journals Gaia DR 2 and VLT/FLAMES search for new satellites of the LMC

2019 ◽  
Vol 623 ◽  
pp. A129 ◽  
Author(s):  
T. K. Fritz ◽  
R. Carrera ◽  
G. Battaglia ◽  
S. Taibi
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Velocity Dispersion ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Mass Function ◽  
Large Magellanic Cloud ◽  
Near Ir ◽  
Dark Matter Mass ◽  
Internal Properties

A wealth of tiny galactic systems populates the surroundings of the Milky Way. However, some of these objects might have originated as former satellites of the Magellanic Clouds, in particular of the Large Magellanic Cloud (LMC). Examples of the importance of understanding how many systems are genuine satellites of the Milky Way or the LMC are the implications that the number and luminosity-mass function of satellites around hosts of different mass have for dark matter theories and the treatment of baryonic physics in simulations of structure formation. Here we aim at deriving the bulk motions and estimates of the internal velocity dispersion and metallicity properties in four recently discovered distant southern dwarf galaxy candidates, Columba I, Reticulum III, Phoenix II, and Horologium II. We combined Gaia DR2 astrometric measurements, photometry, and new FLAMES/GIRAFFE intermediate-resolution spectroscopic data in the region of the near-IR Ca II triplet lines; this combination is essential for finding potential member stars in these low-luminosity systems. We find very likely member stars in all four satellites and are able to determine (or place limits on) the bulk motions and average internal properties of the systems. The systems are found to be very metal poor, in agreement with dwarf galaxies and dwarf galaxy candidates of similar luminosity. Of these four objects, we can only firmly place Phoenix II in the category of dwarf galaxies because of its resolved high velocity dispersion (9.5 −4.4+6.8 km s−1) and intrinsic metallicity spread (0.33 dex). For Columba I we also measure a clear metallicity spread. The orbital pole of Phoenix II is well constrained and close to that of the LMC, suggesting a prior association. The uncertainty on the orbital poles of the other systems is currently very large, so that an association cannot be excluded, except for Columba I. Using the numbers of potential former satellites of the LMC identified here and in the literature, we obtain for the LMC a dark matter mass of M200 = 1.9 −0.9+1.3 × 1011 M⊙.

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