scholarly journals Implications for gravitational lensing and the dark matter content in clusters of galaxies from spatially resolved x-ray spectra

1994 ◽  
Vol 431 ◽  
pp. 91 ◽  
Author(s):  
M. Loewenstein
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Matter Content ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
Spatially Resolved

scholarly journals Dark Matter in Clusters of Galaxies

1995 ◽  
Vol 164 ◽  
pp. 227-235
Author(s):  
Claude R. Canizares
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Rapid Progress ◽  
X Ray ◽  
Mass Distributions ◽  
The Past ◽  
Accurate Picture ◽  
Made In

An appropriate subtitle for this talk might be “Newton meets Einstein.” For many decades, the prime tool for studying the amount and distribution of matter in galaxy clusters was decidedly Newtonian, involving at first the measurements of the dynamics of the galaxies themselves and, for the past 15 years or so, the imputed dynamics of the hot, X-ray emitting intra-cluster gas. Einstein enters more recently with the introduction of gravitational lensing as a tool for studying cluster mass distributions. Rapid progress is being made in each of these areas, and there are now attempts to bring them together to give a consistent and more accurate picture of clusters.

scholarly journals DYNAMICS OF CLUSTERS OF GALAXIES WITH EXTENDED F(chi) GRAVITY

2019 ◽  
Vol 55 (2) ◽  
pp. 237-254
Author(s):  
Tula Bernal ◽  
Oliver López-Corona ◽  
Sergio Mendoza
Keyword(s):  
Dark Matter ◽  
Fourth Order ◽  
Gravitational Lensing ◽  
Relativistic Correction ◽  
Clusters Of Galaxies ◽  
Order Of Approximation ◽  
X Ray ◽  
Flat Rotation Curves ◽  
Theory Of Gravity ◽  
Dynamical Masses

In this article, we present the results of a fourth order perturbation analysis of the metric theory of gravity f(chi) = chi^(3/2) , with chi a suitable dimensionless Ricci scalar. Such a model corresponds to a specific f(R) metric theory of gravity, where the mass of the system is included in the gravitational field's action. In previous works we have shown that, up to the second order in perturbations, this theory reproduces the flat rotation curves of galaxies and the details of the gravitational lensing in individual, groups, and clusters of galaxies. Here, leaving fixed the results from our previous works, we show that the theory reproduces the dynamical masses of 12 Chandra X-ray galaxy clusters, without the need of dark matter, through the metric coefficients up to the fourth order of approximation. In this sense, we calculate the first relativistic correction of the f(chi) metric theory and apply it to fit the dynamical masses of clusters of galaxies.

Weak Gravitational Lensing by a Sample of X‐Ray–luminous Clusters of Galaxies. II. Comparison with Virial Masses

2002 ◽  
Vol 579 (1) ◽  
pp. 227-235 ◽  
Author(s):  
Ragnvald J. Irgens ◽  
Per B. Lilje ◽  
Hakon Dahle ◽  
S. J. Maddox
Keyword(s):  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Weak Gravitational Lensing ◽  
X Ray

scholarly journals Gravitational lenses as probes of the distribution of dark matter in the universe

1986 ◽  
Vol 119 ◽  
pp. 545-546
Author(s):  
R. Cowsik ◽  
P. Ghosh
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Gravitational Lenses ◽  
The Universe ◽  
Individual Galaxies

Studies of the characteristic properties of gravitational lensing by clusters of galaxies suggest that the dark matter in them is probably smoothly distributed on the scale of the cluster itself, rather than being clumped into halos around individual galaxies.

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.

Weak Gravitational Lensing by a Sample of X‐Ray Luminous Clusters of Galaxies. I. The Data Set

2002 ◽  
Vol 139 (2) ◽  
pp. 313-368 ◽  
Author(s):  
Hakon Dahle ◽  
Nick Kaiser ◽  
Ragnvald J. Irgens ◽  
Per B. Lilje ◽  
Steve J. Maddox
Keyword(s):  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
Data Set ◽  
Weak Gravitational Lensing ◽  
X Ray

scholarly journals Astronomical Signatures of Dark Matter

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Paul Gorenstein ◽  
Wallace Tucker
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Background Radiation ◽  
Electromagnetic Spectrum ◽  
Clusters Of Galaxies ◽  
Microwave Background ◽  
Solar Mass ◽  
Rotation Rates ◽  
Microwave Background Radiation ◽  
Unambiguous Detection

Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

scholarly journals Gravitational Lensing of the X‐Ray Background by Clusters of Galaxies

1997 ◽  
Vol 478 (2) ◽  
pp. 476-491 ◽  
Author(s):  
Alexandre Refregier ◽  
Abraham Loeb
Keyword(s):  
Gravitational Lensing ◽  
Clusters Of Galaxies ◽  
X Ray ◽  
X Ray Background
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