scholarly journals The Absence of Adiabatic Contraction of the Radial Dark Matter Profile in the Galaxy Cluster A2589

2006 ◽  
Vol 650 (2) ◽  
pp. 777-790 ◽  
Author(s):  
Luca Zappacosta ◽  
David A. Buote ◽  
Fabio Gastaldello ◽  
Philip J. Humphrey ◽  
James Bullock ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Cluster ◽  
The Galaxy ◽  
Adiabatic Contraction

Studying the Patterns of the Universe

2011 ◽  
Vol 20 (2) ◽  
Author(s):  
T. Sepp ◽  
E. Tempel ◽  
M. Gramann ◽  
P. Nurmi ◽  
M. Haupt
Keyword(s):  
Dark Matter ◽  
Galaxy Cluster ◽  
Analytical Models ◽  
Matter Distribution ◽  
Galaxy Groups ◽  
The Galaxy ◽  
Dark Matter Distribution ◽  
Distribution Studies ◽  
The Universe ◽  
Good Agreement

AbstractThe SDSS galaxy catalog is one of the best databases for galaxy distribution studies. The SDSS DR8 data is used to construct the galaxy cluster catalog. We construct the clusters from the calculated luminosity density field and identify denser regions. Around these peak regions we construct galaxy clusters. Another interesting question in cosmology is how observable galaxy structures are connected to underlying dark matter distribution. To study this we compare the SDSS DR7 galaxy group catalog with galaxy groups obtained from the semi-analytical Millennium N-Body simulation. Specifically, we compare the group richness, virial radius, maximum separation and velocity dispersion distributions and find a relatively good agreement between the mock catalog and observations. This strongly supports the idea that the dark matter distribution and galaxies in the semi-analytical models and observations are very closely linked.

scholarly journals Constraining the abundance of dark matter in the central region of the galaxy cluster MACS J1206.2−0847 with a free-form strong lensing analysis

2020 ◽  
Vol 639 ◽  
pp. A125
Author(s):  
Alberto Manjón-García ◽  
Jose M. Diego ◽  
Diego Herranz ◽  
Daniel Lam
Keyword(s):  
Dark Matter ◽  
Mass Distribution ◽  
Central Region ◽  
Total Mass ◽  
Galaxy Cluster ◽  
Free Form ◽  
Matter Distribution ◽  
Strong Lensing ◽  
The Galaxy ◽  
Dark Matter Distribution

We performed a free-form strong lensing analysis of the galaxy cluster MACS J1206.2−0847 in order to estimate and constrain its inner dark matter distribution. The free-form method estimates the cluster total mass distribution without using any prior information about the underlying mass. We used 97 multiple lensed images belonging to 27 background sources and derived several models, which are consistent with the data. Among these models, we focus on those that better reproduce the radial images that are closest to the centre of the cluster. These radial images are the best probes of the dark matter distribution in the central region and constrain the mass distribution down to distances ∼7 kpc from the centre. We find that the morphology of the innermost radial arcs is due to the elongated morphology of the dark matter halo. We estimate the stellar mass contribution of the brightest cluster galaxy and subtracted it from the total mass in order to quantify the amount of dark matter in the central region. We fitted the derived dark matter density profile with a gNFW, which is characterised by rs = 167 kpc, ρs = 6.7 × 106 M⊙ kpc−3, and γgNFW = 0.70. These results are consistent with a dynamically relaxed cluster. This inner slope is smaller than the cannonical γ = 1 predicted by standard CDM models. This slope does not favour self-interacting models for which a shallower slope would be expected.

scholarly journals The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies

2020 ◽  
Vol 495 (3) ◽  
pp. 3002-3013 ◽  
Author(s):  
Alexander Knebe ◽  
Matías Gámez-Marín ◽  
Frazer R Pearce ◽  
Weiguang Cui ◽  
Kai Hoffmann ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Galaxy Cluster ◽  
Cluster Radius ◽  
Dynamical State ◽  
The Galaxy ◽  
Radial Orbit ◽  
Galaxy Halo ◽  
Satellite Galaxies

ABSTRACT Using 324 numerically modelled galaxy clusters, we investigate the radial and galaxy–halo alignment of dark matter subhaloes and satellite galaxies orbiting within and around them. We find that radial alignment depends on distance to the centre of the galaxy cluster but appears independent of the dynamical state of the central host cluster. Furthermore, we cannot find a relation between radial alignment of the halo or galaxy shape with its own mass. We report that backsplash galaxies, i.e. objects that have already passed through the cluster radius but are now located in the outskirts, show a stronger radial alignment than infalling objects. We further find that there exists a population of well radially aligned objects passing very close to the central cluster’s centre that were found to be on highly radial orbit.

scholarly journals An interesting case of the formation and evolution of a barred galaxy in the cosmological context

2020 ◽  
Vol 642 ◽  
pp. L12
Author(s):  
Ewa L. Łokas
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Cosmic Time ◽  
Galaxy Cluster ◽  
Interesting Case ◽  
Massive Galaxies ◽  
Barred Galaxies ◽  
Tidal Interactions ◽  
The Galaxy ◽  
Formation And Evolution

Elongated, bar-like galaxies without a significant disk component, with little rotation support and no gas, often form as a result of tidal interactions with a galaxy cluster, as was recently demonstrated using the IllustrisTNG-100 simulation. Galaxies that exhibit similar properties are, however, also found to be infalling into the cluster for the first time. We use the same simulation to study in detail the history of such a galaxy over cosmic time in order to determine its origin. The bar appears to be triggered at t = 6.8 Gyr by the combined effect of the last significant merger with a subhalo and the first passage of another dwarf satellite, both ten times less massive than the galaxy. The satellites deposit all their gas in the galaxy, contributing to its third and last star-formation episode, which perturbs the disk and may also contribute to the formation of the bar. The galaxy then starts to lose its gas and dark matter due to its passage near a group of more massive galaxies. The strongest interaction involves a galaxy 22 times more massive, leaving the barred galaxy with no gas and half of its maximum dark matter mass. During this time, the bar grows steadily, seemingly unaffected by the interactions, although they may have aided its growth by stripping the gas. The studied galaxy, together with two other similar objects briefly discussed in this Letter, suggest the existence of a new class of early-type barred galaxies and thereby demonstrate the importance of interactions in galaxy formation and evolution.

scholarly journals Galaxy Distribution as a Probe of the Ringlike Dark Matter Structure in the Galaxy Cluster Cl 0024+17

2008 ◽  
Vol 679 (2) ◽  
pp. L81-L83 ◽  
Author(s):  
Bo Qin ◽  
Huan-Yuan Shan ◽  
Andre Tilquin
Keyword(s):  
Dark Matter ◽  
Galaxy Cluster ◽  
Galaxy Distribution ◽  
The Galaxy

scholarly journals Constraints on Parameters of Radiatively Decaying Dark Matter from the Galaxy Cluster 1E 0657−56

2008 ◽  
Vol 673 (2) ◽  
pp. 752-757 ◽  
Author(s):  
A. Boyarsky ◽  
O. Ruchayskiy ◽  
M. Markevitch
Keyword(s):  
Dark Matter ◽  
Galaxy Cluster ◽  
Decaying Dark Matter ◽  
The Galaxy

Dark Matters, Gravational Force, Neutron Life-Time Anomaly and Hadronization    

2018 ◽  
Author(s):  
Jae-Kwang Hwang
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Electromagnetic Force ◽  
Gravitational Force ◽  
Rest Mass ◽  
Three Dimensional ◽  
Galaxy Cluster ◽  
The Galaxy ◽  
Dark Matters ◽  
Force Range

The properties of the dark matters, dark energy, graviton and photon are discussed in terms of the new three-dimensional quantized space model. Three new particles (bastons) with the electric charges (EC) are proposed as the dark matters. The decreasing coupling constant of the strong force and neutron lifetime anomaly are explained by the unobservable proton and hadronization. And the rest mass of 1.4 TeV/c2 is assigned to the Le particle with the EC charge of −2e. The proposed rest mass (26.12 eV/c2) of the B1 dark matter is indirectly confirmed from the supernova 1987A data. It is proposed that the EC, LC and CC charges are aligned along the time axes but not along the space axes. The photon is confined on its corresponding three-dimensional quantized space. However, the graviton can be evaporated into other three-dimensional quantized spaces. The rest mass and force range of the massive g(0,0,0) graviton with the Planck size are mg = 3.1872·10−31 eV/c2 and xr = 3.0955·1023 m = 10.0 Mpc, respectively, based on the experimental rest mass and rms charge radius of the proton. The possible diameter (10 Mpc) of the largest galaxy cluster is remarkably consistent with the gravitational force range (10 Mpc). Then, the diameter of the largest dark matter distribution related to the largest galaxy cluster is 9.2865·1023 m = 30 Mpc equal to the force range of the massive g(0) graviton with the rest mass of 1.0624·10−31 eV/c2. The reason why the gravitational force between normal matters is very weak when compared with other forces is explained by the graviton evaporation and photon confinement. Because of the huge number (N) of the evaporated gravitons into the x1x2x3 space, it is concluded that the gravitational force between dark matters should be much stronger than the gravitational force between the normal matters and the repulsive electromagnetic force between dark matters. The proposed weak gravitational force between the dark matters and normal matters explains the observed dark matter distributions of the bullet cluster, Abell 1689 cluster and Abell 520 cluster. The transition from the galaxy without the dark matters to the galaxy with the dark matters are explained. Also, the accelerated space expansion is caused by the new space quanta created by the evaporated gravitons into the x1x2x3 space and repulsive electromagnetic force between dark matters corresponding to the dark energy. And the space evolution can be described by using these graviton evaporation and repulsive electromagnetic force, too.

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