Gas Density and X‐Ray Surface Brightness Profiles of Clusters of Galaxies from Dark Matter Halo Potentials: Beyond the Isothermal β‐Model

1998 ◽  
Vol 509 (2) ◽  
pp. 544-550 ◽  
Author(s):  
Yasushi Suto ◽  
Shin Sasaki ◽  
Nobuyoshi Makino
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Dark Matter Halo ◽  
Clusters Of Galaxies ◽  
Gas Density ◽  
X Ray

X‐Ray Gas Density Profile of Clusters of Galaxies from the Universal Dark Matter Halo

1998 ◽  
Vol 497 (2) ◽  
pp. 555-558 ◽  
Author(s):  
Nobuyoshi Makino ◽  
Shin Sasaki ◽  
Yasushi Suto
Keyword(s):  
Dark Matter ◽  
Density Profile ◽  
Dark Matter Halo ◽  
Clusters Of Galaxies ◽  
Gas Density ◽  
X Ray

scholarly journals Brightest cluster galaxies: the centre can(not?) hold

2020 ◽  
Vol 500 (1) ◽  
pp. 310-318
Author(s):  
Roberto De Propris ◽  
Michael J West ◽  
Felipe Andrade-Santos ◽  
Cinthia Ragone-Figueroa ◽  
Elena Rasia ◽  
...  
Keyword(s):  
Dark Matter ◽  
Local Environment ◽  
Major Axis ◽  
Theoretical Models ◽  
Dark Matter Halo ◽  
Gas Distribution ◽  
X Ray ◽  
Cluster Galaxies ◽  
Peculiar Velocities ◽  
Brightest Cluster Galaxies

ABSTRACT We explore the persistence of the alignment of brightest cluster galaxies (BCGs) with their local environment. We find that a significant fraction of BCGs do not coincide with the centroid of the X-ray gas distribution and/or show peculiar velocities (they are not at rest with respect to the cluster mean). Despite this, we find that BCGs are generally aligned with the cluster mass distribution even when they have significant offsets from the X-ray centre and significant peculiar velocities. The large offsets are not consistent with simple theoretical models. To account for these observations BCGs must undergo mergers preferentially along their major axis, the main infall direction. Such BCGs may be oscillating within the cluster potential after having been displaced by mergers or collisions, or the dark matter halo itself may not yet be relaxed.

scholarly journals Simulated X-ray galaxy clusters at the virial radius: Slopes of the gas density, temperature and surface brightness profiles

2006 ◽  
Vol 373 (4) ◽  
pp. 1339-1350 ◽  
Author(s):  
M. Roncarelli ◽  
S. Ettori ◽  
K. Dolag ◽  
L. Moscardini ◽  
S. Borgani ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Surface Brightness ◽  
Gas Density ◽  
X Ray

The X-ray Fundamental Plane of Clusters of Galaxies

2005 ◽  
Vol 201 ◽  
pp. 457-458
Author(s):  
Yutaka. Fujita
Keyword(s):  
Observational Data ◽  
Three Dimensional ◽  
Clusters Of Galaxies ◽  
Core Radius ◽  
Fundamental Plane ◽  
Gas Density ◽  
X Ray

We analyze the relations among the central gas density, core radius, and temperature of X-ray clusters by plotting the observational data in the three-dimensional (log ρgas,0, log rc, and log Tgas) space and find that the data lie on a ‘fundamental plane’. We discuss the implications of the plane.

scholarly journals The dark matter halos of spheroidal galaxies and clusters of galaxies

2004 ◽  
Vol 220 ◽  
pp. 159-164 ◽  
Author(s):  
Tommaso Treu ◽  
Léon V. E. Koopmans ◽  
David J. Sand ◽  
Graham P. Smith ◽  
Richard S. Ellis
Keyword(s):  
Dark Matter ◽  
Mass Density ◽  
Hubble Constant ◽  
Dark Matter Halo ◽  
Dynamical Analysis ◽  
Delay Systems ◽  
Clusters Of Galaxies ◽  
Dark Matter Halos ◽  
Gravitational Lenses ◽  
Stellar Component

We describe the first results from two observational projects aimed at measuring the amount and spatial distribution of dark matter in distant early-type galaxies (E/S0s) and clusters of galaxies. At the galaxy scale, the Lenses Structure and Dynamics (LSD) Survey is gathering kinematic data for distant (up to z ⋐ 1) E/S0s that are gravitational lenses. A joint lensing and dynamical analysis constrains the fraction of dark matter within the Einstein radius, the mass-to-light ratio of the stellar component, and the total slope of the mass density profile. These properties and their evolution with redshift are briefly discussed in terms of the formation and evolution of E/S0 galaxies and measurement of the Hubble Constant from gravitational time delay systems. At the cluster scale – after careful removal of the stellar component with a joint lensing and dynamical analysis – systems with giant radial arcs can be used to measure precisely the inner slope of the dark matter halo. An HST search for radial arcs and the analysis of a first sample are briefly discussed in terms of the universal dark matter halos predicted by CDM simulations.

scholarly journals Dark matter and X-ray halo in early-type galaxies and clusters of galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 89-90
Author(s):  
Takaya Ohashi
Keyword(s):  
Dark Matter ◽  
Clusters Of Galaxies ◽  
Large Scatter ◽  
Early Type ◽  
Matter Distribution ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Luminous Galaxies ◽  
Dark Matter Distribution

X-ray observations reveal extended halos around early-type galaxies which enable us to trace the dark matter distribution around the galaxies (see Mathews and Brighenti 2003 for a review). X-ray luminosities, LX of massive early-type galaxies are 1040−1042 erg s−1 in 0.3–2 keV. The correlation plot between LX and B-band luminosity LB shows a large scatter in the sense that LX varies by 2 orders of magnitudes for the same LB, in the brightest end (log LB ≳ 10.5). The amount of the X-ray hot gas in early-type galaxies is typically a few % of the stellar mass, in contrast to clusters of galaxies which hold ~5 times more massive gas than stars. Matsushita (2001) showed that X-ray luminous galaxies are characterized by extended X-ray halo with a few tens of re, similar to the scale of galaxy groups, so the presence of group-size potentials would be strongly linked with the problem of large LX scatter.

scholarly journals ASCA Observations of Three Gravitational Lensing Clusters of Galaxies; CL0500-24, CL2244-02, and A370

1998 ◽  
Vol 188 ◽  
pp. 319-320
Author(s):  
Naomi Ota ◽  
Kazuhisa Mitsuda ◽  
Yasushi Fukazawa
Keyword(s):  
Gravitational Lensing ◽  
Surface Brightness ◽  
Clusters Of Galaxies ◽  
X Ray

We determined the X-ray temperatures of three gravitational lensing clusters, CL0500-24, CL2244-02, and A370, and obtained significant constraints on the surface brightness profile assuming the β-model and the King model profiles. The mass of the cluster estimated from these X-ray data is by a factor of two to three smaller than the mass estimated from lens models for two of the clusters.

scholarly journals Massive low-surface-brightness galaxies in the eagle simulation

2020 ◽  
Vol 496 (3) ◽  
pp. 3996-4016
Author(s):  
Andrea Kulier ◽  
Gaspar Galaz ◽  
Nelson D Padilla ◽  
James W Trayford
Keyword(s):  
Dark Matter ◽  
Angular Momentum ◽  
Surface Density ◽  
Surface Brightness ◽  
Initial Conditions ◽  
High Surface ◽  
Formation Rate ◽  
Dark Matter Halo ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

ABSTRACT We investigate the formation and properties of low surface brightness galaxies (LSBGs) with M* > 109.5 M⊙ in the eagle hydrodynamical cosmological simulation. Galaxy surface brightness depends on a combination of stellar mass surface density and mass-to-light ratio (M/L), such that low surface brightness is strongly correlated with both galaxy angular momentum (low surface density) and low specific star formation rate (high M/L). This drives most of the other observed correlations between surface brightness and galaxy properties, such as the fact that most LSBGs have low metallicity. We find that LSBGs are more isolated than high-surface-brightness galaxies (HSBGs), in agreement with observations, but that this trend is driven entirely by the fact that LSBGs are unlikely to be close-in satellites. The majority of LSBGs are consistent with a formation scenario in which the galaxies with the highest angular momentum are those that formed most of their stars recently from a gas reservoir co-rotating with a high-spin dark matter halo. However, the most extended LSBG discs in EAGLE, which are comparable in size to observed giant LSBGs, are built up via mergers. These galaxies are found to inhabit dark matter haloes with a higher spin in their inner regions (<0.1r200c), even when excluding the effects of baryonic physics by considering matching haloes from a dark-matter-only simulation with identical initial conditions.

scholarly journals Development of New Analysis Method for Mapping Observations of Clusters of Galaxies

1998 ◽  
Vol 188 ◽  
pp. 312-313
Author(s):  
K. Kikuchi ◽  
T. Ohashi ◽  
H. Ezawa ◽  
M. Hirayama ◽  
H. Honda ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Stray Light ◽  
Physical Parameters ◽  
Clusters Of Galaxies ◽  
X Rays ◽  
X Ray ◽  
Hot Gas ◽  
Cluster Data ◽  
Metal Abundance ◽  
Analysis System

Mapping observations of nearby large-extended clusters of galaxies (Coma, Perseus, Virgo, etc.) are being performed with ASCA. Such clusters allow us to map physical parameters of hot gas in the clusters, such as temperature, metal abundance, and X-ray surface brightness. To determine such parameters at each part of a cluster, one should take careful care of X-ray contamination from outside of a pointed field, which is mainly due to “stray-light” X-rays (Honda et al. 1997). For this reason, the only way to obtain the distribution of hot gas parameter is to process the whole cluster data in a self-consistent way. For this purpose, we are developing the new analysis system called TERRA.

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