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Related papers: Clustering of absorption line systems

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Clusters of galaxies are used in a variety of ways to do cosmology. Some of them are presented here. Their X-ray emitting gas allows us to determine the baryon fraction, dark matter distribution and the matter density $\Omega_{m}$ of the…

Astrophysics · Physics 2007-05-23 Africa Castillo-Morales , Sabine Schindler

Quasar absorption lines provide detailed information on the chemical, kinematic, and ionization conditions in galaxies and their environments, and provide a means for studying the evolution of these conditions back to the epoch of the first…

Astrophysics · Physics 2007-05-23 Jane C. Charlton , Christopher W. Churchill

I critically review a methodology of using clusters of galaxies as cosmological probes. The understanding of the abundances and spatial correlations of dark matter halos has been significantly advanced especially for a last few years.…

Astrophysics · Physics 2007-05-23 Yasushi Suto

Time series, as one of the most fundamental representations of sequential data, has been extensively studied across diverse disciplines, including computer science, biology, geology, astronomy, and environmental sciences. The advent of…

Machine Learning · Computer Science 2024-12-31 John Paparrizos , Fan Yang , Haojun Li

Various cosmological applications of galaxy clusters are presented. Clusters are used to determine the baryon fraction, dark matter distribution and the matter density of the universe. They also contain a wealth of information about…

Astrophysics · Physics 2007-05-23 Sabine Schindler

Clusters of galaxies, being dark matter dominated, have long been and still are the ideal cosmological targets to study the nature of dark matter. Constraints on the nature of dark matter comes in particular from the observational…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-06 A. Biviano

The large scale structure of the present Universe is determined by the growth of dark matter density fluctuations and by the dynamical action of dark energy and dark matter. While much progress has been made in recent years in constraining…

The physical nature of the material responsible for the high--velocity, broad-absorption line features seen in a small fraction of quasar spectra has been the subject of debate since their discovery. This has been especially compounded by…

Astrophysics · Physics 2009-10-30 Geraint F. Lewis , Kunegunda E. Belle

We examine the line-of-sight clustering of QSO heavy-element absorption-line systems, using a new measure of clustering, called the reduced second moment measure, that directly measures the mean over-density of absorbers. While closely…

Astrophysics · Physics 2009-10-30 Jean M. Quashnock , Michael L. Stein

Galaxy clusters as gravitational lenses play a unique role in astrophysics and cosmology: they permit mapping the dark matter distribution on a range of scales; they reveal the properties of high and intermediate redshift background…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-12 Priyamvada Natarajan , Liliya L. Williams , Marusa Bradac , Claudio Grillo , Agniva Ghosh , Keren Sharon , Jenny Wagner

QSOs and radio-galaxies, together with the CMB, ``normal'' galaxies and clusters, represent the main source of information about the origin and evolution of the Large Scale Structure. They can be used either directly, as tracers of the…

Astrophysics · Physics 2007-05-23 S. Cristiani

I review our current knowledge of the mass distribution in clusters, as obtained from the analysis of the projected phase-space distribution of cluster galaxies. I discuss the methods of analysis, their relative advantages and…

Astrophysics · Physics 2007-05-23 Andrea Biviano

Clusters of galaxies are large gravitationally bound systems which consist of several observable components: hundreds of galaxies, hot gas between the galaxies and sometimes relativistic particles. These components are emitting in different…

Astrophysics · Physics 2007-05-23 Sabine Schindler

Rich clusters of galaxies, the largest virialized systems known, provide a powerful tool for the study of cosmology. Some of the fundamental questions that can be addressed with clusters of galaxies include: how did galaxies and large-scale…

Astrophysics · Physics 2007-05-23 Neta A. Bahcall

I present here a review of Large-Scale Structure (LSS) studies using clusters of galaxies. First, I re-evaluate the `pros' and `cons' of using clusters for such studies, especially in this era of large galaxy redshift surveys. Secondly, I…

Astrophysics · Physics 2007-05-23 R. C. Nichol

Star clusters are ideal tracers of star formation activity in systems outside the volume that can be studied using individual, resolved stars. These unresolved clusters span orders of magnitude in brightness and mass, and their formation is…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-20 I. S. Konstantopoulos , K. Fedotov , S. C. Gallagher , A. Maybhate , P. R. Durrell , J. C. Charlton

Clustering is an unsupervised machine learning methodology where unlabeled elements/objects are grouped together aiming to the construction of well-established clusters that their elements are classified according to their similarity. The…

Machine Learning · Statistics 2023-10-20 Dimitrios Saligkaras , Vasileios E. Papageorgiou

In cluster tomography, we propose measuring the number of clusters $N$ intersected by a line segment of length $\ell$ across a finite sample. As expected, the leading order of $N(\ell)$ scales as $a\ell$, where $a$ depends on microscopic…

Disordered Systems and Neural Networks · Physics 2024-02-13 Helen S. Ansell , Samuel J. Frank , István A. Kovács

Gravitational Lensing is an efficient tool to probe: the mass distribution of collapsed systems: galaxies and clusters; high redshift objects thanks to the gravitational amplification; and the geometry of the Universe. I will review here…

Astrophysics · Physics 2007-05-23 J. -P. Kneib