X-ray clusters of galaxies as tracers of structure in the Universe

X-ray emission from clusters of galaxies is the most useful tool in studying mass distribution and chemical compositions in these enormously large systems. The hot intracluster medium (ICM) has been heated up to kT = 3–10 keV during the gravitational collapse, and X-ray luminosities indicate that the gas is more massive than the total galaxy mass contained in clusters by factors of 3–5. This makes ICM the dominant form of baryons in the universe. In many clusters observations indicate that ICM is in a hydrostatic equilibrium within a potential governed by the dark matter, and the cooling time is longer than the Hubble time except for the bright centers. The ICM, therefore, enables us a close look at the structure of gravitational potential. At the same time, heavy-element abundances in the ICM and their distribution are used to estimate past supernova activities and metal injection mechanism in cluster space.

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Intergalactic Matter and Radiation and its Bearing on Galaxy Formation and Evolution

Symposium - International Astronomical Union ◽

10.1017/s0074180900024347 ◽

1974 ◽

Vol 58 ◽

pp. 93-108

Author(s):

G. R. Burbidge

Keyword(s):

Galaxy Formation ◽

High Mass ◽

Clusters Of Galaxies ◽

X Ray ◽

Hot Gas ◽

Galaxy Formation And Evolution ◽

Formation And Evolution ◽

The Universe ◽

Very High ◽

Theoretical Standpoint

An up-dated review is given of the evidence for the presence of intergalactic matter and radiation in the Universe. It is concluded that the only important constituents which may make a sizable contribution to the total mass-energy are intergalactic gas and condensed objects with a very high mass-to-light ratio. If the QSOs are not at cosmological distances, cold atomic hydrogen may still be the most important constituent and may contribute much more mass than do the galaxies. The X-ray observations still do not unambiguously show that very hot gas is present, though it is very likely on general grounds that some hot gas is present in clusters of galaxies.The question of whether or not large amounts of matter, enough to close the Universe, are present, remains unsettled. From the theoretical standpoint the answer depends almost completely on the approach taken to the problem of galaxy formation and to the cosmological model which is favoured.

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The X-Ray Background: Origin and Implications

Symposium - International Astronomical Union ◽

10.1017/s007418090006856x ◽

1980 ◽

Vol 92 ◽

pp. 207-225

Author(s):

Martin J. Rees

Keyword(s):

Large Scale ◽

Clusters Of Galaxies ◽

X Ray ◽

X Ray Background ◽

The Universe

This paper will be concerned with three topics relevant to the X-ray background: (i) X-ray emission mechanisms in quasars; (ii) the contributions to the X-ray background from quasars, clusters of galaxies, intercluster gas, young galaxies, etc; and (iii) the use of X-ray background observations as a probe for large-scale density irregularities in the Universe.

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Clusters of Galaxies in a Flat CHDM Universe

Symposium - International Astronomical Union ◽

10.1017/s0074180900115232 ◽

1998 ◽

Vol 188 ◽

pp. 299-299

Author(s):

A. Habe ◽

C. Hanyu ◽

S. Yachi

Keyword(s):

Dark Matter ◽

Large Scale ◽

Large Scale Structure ◽

Numerical Results ◽

Clusters Of Galaxies ◽

Statistical Features ◽

X Ray ◽

Numerical Resolution ◽

Radiative Processes ◽

The Universe

Cold and hot dark matter (CHDM) model is one of viable models which can reproduce the large scale structure of the universe. HDM may affect structure of clusters of galaxies in CHDM universe. Bryan et al. (1994) gave numerical results of CHDM model that explain some statistical features of X-ray clusters of galaxies, e.g. X-ray luminosiry-temperature realtion, L ∝~ T3.5, without considering radiative processes. However their numerical resolution is insufficient to resolve the cores of X-ray clusters. So, we simulate the formation of clusters in CHDM universe more carefully.

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NEW RESULTS FROM H.E.S.S. OBSERVATIONS OF GALAXY CLUSTERS

International Journal of Modern Physics D ◽

10.1142/s021827180901545x ◽

2009 ◽

Vol 18 (10) ◽

pp. 1627-1631 ◽

Cited By ~ 9

Author(s):

◽

WILFRIED DOMAINKO ◽

DALIBOR NEDBAL ◽

JAMES A. HINTON ◽

OLIVIER MARTINEAU-HUYNH

Keyword(s):

Cosmic Rays ◽

Galaxy Clusters ◽

Gamma Rays ◽

Large Scale ◽

Gamma Ray ◽

Cosmic Ray ◽

Clusters Of Galaxies ◽

X Ray ◽

Model Predictions ◽

The Universe

Clusters of galaxies are believed to contain a significant population of cosmic rays. From the radio and probably hard X-ray bands it is known that clusters are the spatially most extended emitters of non-thermal radiation in the Universe. Due to their content of cosmic rays, galaxy clusters are also potential sources of VHE (> 100 GeV) gamma rays. Recently, the massive, nearby cluster Abell 85 has been observed with the H.E.S.S. experiment in VHE gamma rays with a very deep exposure as part of an ongoing campaign. No significant gamma-ray signal has been found at the position of the cluster. The non-detection of this object with H.E.S.S. constrains the total energy of cosmic rays in this system. For a hard spectral index of the cosmic rays of -2.1 and if the cosmic-ray energy density follows the large scale gas density profile, the limit on the fraction of energy in these non-thermal particles with respect to the total thermal energy of the intra-cluster medium is 8% for this particular cluster. This value is at the lower bounds of model predictions.

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Fluctuations of the Microwave Background Radiation

Symposium - International Astronomical Union ◽

10.1017/s0074180900144857 ◽

1978 ◽

Vol 79 ◽

pp. 393-404

Author(s):

R. A. Sunyaev

Keyword(s):

Large Scale ◽

Background Radiation ◽

Small Scale ◽

Clusters Of Galaxies ◽

Microwave Background ◽

X Ray ◽

M 10 ◽

Microwave Background Radiation ◽

Density Perturbations ◽

The Universe

Investigations of small scale angular fluctuations and the spectrum of the microwave background radiation is one of the main methods of studying the large scale structure of the Universe. Figure 1 shows the principal stages of the evolution of the Universe. Today we can directly observe galaxies, clusters of galaxies and quasars in the redshift range z ≤ 3.5 by optical, radio and X-ray astronomy. These observations show that significant density perturbations δρ/ρ > 1 are present on mass scales M < 1016 M⊙. the Universe is essentially uniform δρ/ρ < 1 on large scales M ≫ 1016 M⊙.

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Beyond the Schwarzschild Metric

10.1093/oso/9780199658633.003.0019 ◽

2018 ◽

Author(s):

David M. Wittman

Keyword(s):

Black Holes ◽

General Relativity ◽

Gravitational Waves ◽

Test Particle ◽

Direct Detection ◽

Relativistic Effects ◽

Big Bang ◽

Clusters Of Galaxies ◽

General Relativistic ◽

The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

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Quantiles as Robust Probes of Non-Gaussianity in 21-cm Images

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab318 ◽

2021 ◽

Author(s):

Alon Banet ◽

Rennan Barkana ◽

Anastasia Fialkov ◽

Or Guttman

Keyword(s):

Galactic Halo ◽

Angular Resolution ◽

Research Effort ◽

First Stars ◽

X Ray ◽

Global Signal ◽

Radio Background ◽

Halo Masses ◽

The Universe ◽

Cosmic History

Abstract The epoch in which the first stars and galaxies formed is among the most exciting unexplored eras of the Universe. A major research effort is focused on probing this era with the 21-cm spectral line of hydrogen. While most research focuses on statistics like the 21-cm power spectrum or the sky-averaged global signal, there are other ways to analyze tomographic 21-cm maps, which may lead to novel insights. We suggest statistics based on quantiles as a method to probe non-Gaussianities of the 21-cm signal. We show that they can be used in particular to probe the variance, skewness, and kurtosis of the temperature distribution, but are more flexible and robust than these standard statistics. We test these statistics on a range of possible astrophysical models, including different galactic halo masses, star-formation efficiencies, and spectra of the X-ray heating sources, plus an exotic model with an excess early radio background. Simulating data with angular resolution and thermal noise as expected for the Square Kilometre Array (SKA), we conclude that these statistics can be measured out to redshifts above 20 and offer a promising statistical method for probing early cosmic history.

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A Systematic X‐Ray Search for Clusters of Galaxies behind the Milky Way. II. The Second CIZA Subsample

The Astrophysical Journal ◽

10.1086/513303 ◽

2007 ◽

Vol 662 (1) ◽

pp. 224-235 ◽

Cited By ~ 71

Author(s):

Dale D. Kocevski ◽

Harald Ebeling ◽

Chris R. Mullis ◽

R. Brent Tully

Keyword(s):

Milky Way ◽

Clusters Of Galaxies ◽

X Ray

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The Voyage of Metals in the Universe from Cosmological to Planetary Scales: the need for a Very High-Resolution, High Throughput Soft X-ray Spectrometer

Experimental Astronomy ◽

10.1007/s10686-021-09710-2 ◽

2021 ◽

Author(s):

F. Nicastro ◽

J. Kaastra ◽

C. Argiroffi ◽

E. Behar ◽

S. Bianchi ◽

...

Keyword(s):

Chemical Composition ◽

High Resolution ◽

Deep Understanding ◽

High Resolution Spectroscopy ◽

X Ray ◽

Viable Solution ◽

Surrounding Space ◽

Nuclear Processes ◽

The Universe ◽

Very High

AbstractMetals form an essential part of the Universe at all scales. Without metals we would not exist, and the Universe would look completely different. Metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. The wanderings of metals in-and-out of astronomical objects are crucial in determining their own evolution and thus that of the Universe as a whole. Detecting metals and assessing their relative and absolute abundances and energetics can thus be used to trace the evolution of these cosmic components. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe’s wandering metals, their physical and kinematical states, and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.

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