Download or read book The Influence of Physical Processes in Galaxy Clusters on Observable Cluster Scaling Relations written by Hsiang-Yi Yang and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of galaxies, which occupy a unique position in hierarchical structure formation, are invaluable cosmological probes and laboratories for astrophysical processes. Cluster scaling relations, which connect their masses and observable properties, provide the link between these two roles. Cosmological constraints derived from cluster abundances often rely on calibrations or functional forms of these relations. On the other hand, the form and evolution of the mass-observable relations are affected by astrophysical processes during cluster formation. Understanding these processes not only provides insights into cluster physics but also has important implications for cluster cosmology. In this thesis, we use numerical simulations to study the influence of important physical mechanisms, including gravity, radiative cooling, and heating from active galactic nuclei (AGN), on cluster mass-observable relations. In particular, we investigate the physical origin of the intrinsic scatter around the best-fit relations by correlating it with measures of cluster structure, dynamical state, and AGN activity. Using a cosmological N -body plus hydrodynamic simulation produced using the FLASH code, we study the impact of cluster structure and dynamical state on the distribution of scatter in the X-ray temperature and Sunyaev-Zel0́9dovich (SZ) scaling relations. We also examine possible systematic biases in cluster cosmology, such as sample selection in cluster surveys, assumptions in self-calibration studies, and correlated errors in combining X-ray and SZ mass estimates. Correctly simulating cluster properties, especially inside cluster cores, requires additional baryonic physics, including radiative cooling and some heating mechanisms such as AGN feedback. However, because of the extreme dynamic range required to capture the rich physics involved in accretion onto and feedback by the supermassive black holes (SMBH) in AGN, current modeling of AGN in cosmological simulations is highly phenomenological and relies on heterogeneous parameterizations. We perform a systematic sensitivity study on a variety of these models and parameters and quantify the current theoretical uncertain- ties in the predicted cluster global quantities. This study is an important step toward the development of more robust AGN models within a cosmological framework.
Download or read book Merging Processes in Galaxy Clusters written by L. Feretti and published by Springer Science & Business Media. This book was released on 2006-04-18 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mergers are the mechanisms by which galaxy clusters are assembled through the hierarchical growth of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. Many of the observed properties of clusters depend on the physics of the merging process. These include substructure, shock, intra cluster plasma temperature and entropy structure, mixing of heavy elements within the intra cluster medium, acceleration of high-energy particles, formation of radio halos and the effects on the galaxy radio emission. This book reviews our current understanding of cluster merging from an observational and theoretical perspective, and is appropriate for both graduate students and researchers in the field.
Download or read book Clusters of Galaxies Physics and Cosmology written by Andrei M. Bykov and published by Springer. This book was released on 2019-10-17 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of galaxies are large assemblies of galaxies, hot gas and dark matter bound together by gravity. Galaxy clusters are now one of the most important cosmological probes to test the standard cosmological models. Constraints on the Dark Energy equation of state from the cluster number density measurements, deviations from the Gaussian perturbation models, the Sunyaev-Zeldovich effect as well as the dark matter proles are among the issues to be studied with clusters. The baryonic composition of clusters is dominated by hot gas that is in quasi-hydrostatic equilibrium within the dark matter-dominated gravitational potential well of the cluster. The hot gas is visible through spatially extended thermal X-ray emission, and it has been studied extensively both for assessing its physical properties and as a tracer of the large-scale structure of the Universe. Magnetic fields as well as a number of non-thermal plasma processes play a role in clusters of galaxies as we observe from radioastronomical observations. The goal of this volume is to review these processes and to investigate how they are interlinked. Overall, these papers provide a timely and comprehensive review of the multi-wavelength observations and theoretical understanding of clusters of galaxies in the cosmological context. Thus, the volume will be particularly useful to postgraduate students and researchers active in various areas of astrophysics and space science. Originally published in Space Science Reviews in the Topical Collection "Clusters of Galaxies: Physics and Cosmology"
Download or read book The Impact of Non Thermal Processes in the Intracluster Medium on Cosmological Cluster Observables written by Nicholas Ambrose Battaglia and published by . This book was released on 2011 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis we describe the generation and analysis of hydrodynamical simulations of galaxy clusters and their intracluster medium (ICM), using large cosmological boxes to generate large samples, in conjunction with individual cluster computations. The main focus is the exploration of the non-thermal processes in the ICM and the effect they have on the interpretation of observations used for cosmological constraints. We provide an introduction to the cosmological structure formation framework for our computations and an overview of the numerical simulations and observations of galaxy clusters. We explore the cluster magnetic field observables through radio relics, extended entities in the ICM characterized by their of diffuse radio emission. We show that statistical quantities such as radio relic luminosity functions and rotation measure power spectra are sensitive to magnetic field models. The spectral index of the radio relic emission provides information on structure formation shocks, e.g., on their Mach number. We develop a coarse grained stochastic model of active galaxy nucleus (AGN) feed-back in clusters and show the impact of such inhomogeneous feedback on the thermal pressure profile. We explore variations in the pressure profile as a function of cluster mass, redshift, and radius and provide a constrained fitting function for this profile. We measure the degree of the non-thermal pressure in the gas from internal cluster bulk motions and show it has an impact on the slope and scatter of the Sunyaev-Zel'dovich (SZ) scaling relation. We also find that the gross shape of the ICM, as characterized by scaled moment of inertia tensors, affects the SZ scaling relation. We demonstrate that the shape and the amplitude of the SZ angular power spectrum is sensitive to AGN feedback, and this affects the cosmological parameters determined from high resolution ACT and SPT cosmic microwave background data. We compare analytic, semi-analytic, and simulation-based methods for calculating the SZ power spectrum, and characterize their differences. All the methods must rely, one way or another, on high resolution large-scale hydrodynamical simulations with varying assumptions for modelling the gas of the sort presented here. We show how our results can be used to interpret the latest ACT and SPT power spectrum results. We provide an outlook for the future, describing follow-up work we are undertaking to further advance the theory of cluster science.
Download or read book Handbook of X ray and Gamma ray Astrophysics written by Cosimo Bambi and published by Springer Nature. This book was released on with total page 5912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Pan Chromatic View of Clusters of Galaxies and the Large Scale Structure written by Manolis Plionis and published by Springer Science & Business Media. This book was released on 2008-02-29 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reviews presented in this volume cover a huge range of cluster of galaxies topics. Readers will find the book essential reading on subjects such as the physics of the ICM gas, the internal cluster dynamics, and the detection of clusters using different observational techniques. The expert chapter authors also cover the huge advances being made in analytical or numerical modeling of clusters, weak and strong lensing effects, and the large scale structure as traced by clusters.
Download or read book Measurement of Galaxy Cluster Integrated Comptonization and Mass Scaling Relations with the South Pole Telescope written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a method for measuring the integrated Comptonization (Y (SZ)) of clusters of galaxies from measurements of the Sunyaev-Zel'dovich (SZ) effect in multiple frequency bands and use this method to characterize a sample of galaxy clusters detected in the South Pole Telescope (SPT) data. We use a Markov Chain Monte Carlo method to fit a [beta]-model source profile and integrate Y (SZ) within an angular aperture on the sky. In simulated observations of an SPT-like survey that include cosmic microwave background anisotropy, point sources, and atmospheric and instrumental noise at typical SPT-SZ survey levels, we show that we can accurately recover [beta]-model parameters for inputted clusters. We measure Y (SZ) for simulated semi-analytic clusters and find that Y (SZ) is most accurately determined in an angular aperture comparable to the SPT beam size. We demonstrate the utility of this method to measure Y (SZ) and to constrain mass scaling relations using X-ray mass estimates for a sample of 18 galaxy clusters from the SPT-SZ survey. Measuring Y (SZ) within a 0.'75 radius aperture, we find an intrinsic log-normal scatter of 21% ± 11% in Y (SZ) at a fixed mass. Measuring Y (SZ) within a 0.3 Mpc projected radius (equivalent to 0.'75 at the survey median redshift z = 0.6), we find a scatter of 26% ± 9%. Prior to this study, the SPT observable found to have the lowest scatter with mass was cluster detection significance. We demonstrate, from both simulations and SPT observed clusters that Y (SZ) measured within an aperture comparable to the SPT beam size is equivalent, in terms of scatter with cluster mass, to SPT cluster detection significance.
Download or read book Clusters of Galaxies Beyond the Thermal View written by Jelle Kaastra and published by Springer Science & Business Media. This book was released on 2008-05-01 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: The existence of soft excess emission originating from clusters of galaxies, de ned as em- sion detected below 1 keV in excess over the usual thermal emission from hot intracluster gas (hereafter the ICM) has been claimed since 1996. Soft excesses are particularly - portant to detect because they may (at least partly) be due to thermal emission from the Warm-Hot Intergalactic Medium, where as much as half of the baryons of the Universe could be. They are therefore of fundamental cosmological importance. Soft excess emission has been observed (and has also given rise to controversy) in a number of clusters, mainly raising the following questions: (1) Do clusters really show a soft excess? (2) If so, from what spatial region(s) of the cluster does the soft excess or- inate? (3) Is this excess emission thermal, originating from warm-hot intergalactic gas (at 6 temperatures of?10 K), or non-thermal, in which case several emission mechanisms have been proposed. Interestingly, some of the non-thermal mechanisms suggested to account for soft excess emission can also explain the hard X-ray emission detected in some clusters, for example by RXTE and BeppoSAX (also see Petrosian et al. 2008—Chap. 10, this issue; Rephaeli et al. 2008—Chap. 5, this issue).
Download or read book Extragalactic Astronomy and Cosmology written by Peter Schneider and published by Springer. This book was released on 2014-10-08 with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition has been updated and substantially expanded. Starting with the description of our home galaxy, the Milky Way, this cogently written textbook introduces the reader to the astronomy of galaxies, their structure, active galactic nuclei, evolution and large scale distribution in the Universe. After an extensive and thorough introduction to modern observational and theoretical cosmology, the focus turns to the formation of structures and astronomical objects in the early Universe. The basics of classical astronomy and stellar astrophysics needed for extragalactic astronomy are provided in the appendix. While this book has grown out of introductory university courses on astronomy and astrophysics and includes a set of problems and solutions, it will not only benefit undergraduate students and lecturers; thanks to the comprehensive coverage of the field, even graduate students and researchers specializing in related fields will appreciate it as a valuable reference work.
Download or read book A Multi wavelength Study of Optically Selected Galaxy Clusters from the Blanco Cosmology Survey written by Lindsey Ellen Bleem and published by . This book was released on 2013 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abundance measurements of galaxy clusters provide powerful constraints of cosmology. The observed distribution of clusters can potentially be used to disentangle whether the accelerated cosmic expansion can be explained by a modification to Einstein's theory of gravity or whether the explanation involves a new form of 'dark' energy. Such growth of structure measurements are both complementary to and provide an important cross-check of measurements of the geometry of the universe. There are two key requirements for cosmology with galaxy clusters: a census of these systems through cosmic time and the ability to connect the measured signal with the underlying mass of the galaxy cluster. In this era of large-area millimeter and optical wavelength surveys (including the South Pole Telescope (SPT) 2500-square-degree SZ-Survey and the Dark Energy Survey (DES)) where hundreds (mm-wave) to hundreds of thousands (optical) of clusters will be detected, the most serious limitation to cluster cosmology remains understanding and calibrating observable-mass relations. Combining cluster observables across wavelengths can both test and inform our knowledge of such scaling relations. As a pilot program for future explorations of the combined SPT and DES datasets, we explore the relation between the optical-richness, lambda, and SZ-signal for a sample of 567 optically-selected clusters from the Blanco Cosmology Survey, an ~ 80 square-degree survey located within the SPT-SZ survey. In this study we detect SZ-signal at increasing significance as a function of cluster richness but find that the recovered signal falls below expectations derived from models based on X-ray samples. We explore possible biases to our recovered signal and find that contamination from cluster members -- in particular radio and dust emission from galaxies--is small and that the majority of the discrepancy at the high mass end can be explained by errors in identifying the optical centers of clusters. The toolset developed here can be combined with future cluster catalogs from the Dark Energy Survey to help improve mass-richness scaling relations and ultimately constrain cosmological models.
Download or read book Understanding the Physical Processes Driving Galaxy Evolution in Clusters written by Sean M. Moran and published by . This book was released on 2008 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Precision Cosmology with Galaxy Cluster Surveys written by Hao-Yi Wu and published by Stanford University. This book was released on 2011 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The acceleration of the universe, which is often attributed to "dark energy, " has posed one of the main challenges to fundamental physics. Galaxy clusters provide one of the most sensitive probes of dark energy because their abundance reflects the growth rate of large-scale structure and the expansion rate of the universe. Several large galaxy cluster surveys will soon provide tremendous statistical power to constrain the properties of dark energy; however, the constraining power of these surveys will be determined by how well systematic errors are controlled. Of these systematic errors, the dominant one comes from inferring cluster masses using observable signals of clusters, the so-called "observable--mass distribution." This thesis focuses on extracting dark energy information from forthcoming large galaxy cluster surveys, including how we maximize the cosmological information, how we control important systematics, and how precisely we need to calibrate theoretical models. We study how multi-wavelength follow-up observations can improve cluster mass calibration in optical surveys. We also investigate the impact of theoretical uncertainties in calibrating the spatial distributions of galaxy clusters on dark energy constraints. In addition, we explore how the formation history of galaxy clusters impacts the self-calibration of cluster mass. In addition, we use N-body simulations to develop a new statistical sample of cluster-size halos in order to further understand the observable--mass distribution. We study the completeness of subhalos in our cluster sample by comparing them with the satellite galaxies in the Sloan Digital Sky Survey. We also study how subhalo selections impact the inferred correlation between formation time and optical mass tracers, including cluster richness and velocity dispersion.
Download or read book Multi scale Structure Formation and Dynamics in Cosmic Plasmas written by Andre Balogh and published by Springer. This book was released on 2016-02-02 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers eleven coordinated reviews on multi-scale structure formation in cosmic plasmas in the Universe. Observations and theories of plasma structures are presented in all relevant astrophysical contexts, from the Earth’s magnetosphere through heliospheric and galactic scales to clusters of galaxies and the large scale structure of the Universe. Basic processes in cosmic plasmas starting from electric currents and the helicity concept governing the dynamics of magnetic structures in planet magnetospheres, stellar winds, and relativistic plasma outflows like pulsar wind nebulae and Active Galactic Nuclei jets are covered. The multi-wavelength view from the radio to gamma-rays with modern high resolution telescopes discussed in the book reveals a beautiful and highly informative picture of both coherent and chaotic plasma structures tightly connected by strong mutual influence. The authors are all leading scientists in their fields, making this book an authoritative, up‐to‐date and enduring contribution to astrophysics.
Download or read book A Pan Chromatic View of Clusters of Galaxies and the Large Scale Structure written by Manolis Plionis and published by Springer. This book was released on 2009-09-03 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reviews presented in this volume cover a huge range of cluster of galaxies topics. Readers will find the book essential reading on subjects such as the physics of the ICM gas, the internal cluster dynamics, and the detection of clusters using different observational techniques. The expert chapter authors also cover the huge advances being made in analytical or numerical modeling of clusters, weak and strong lensing effects, and the large scale structure as traced by clusters.
Download or read book Background Microwave Radiation and Intracluster Cosmology written by F. Melchiorri and published by IOS Press. This book was released on 2006-01-24 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is devoted to the Sunyaev-Zeldovich (S-Z) effect, and important related topics in cluster and CMB research. S-Z science is about to be significantly enhanced by unique, multi-faceted cluster and cosmological yield, at a level of precision in accord with the high standards of the current era that was heralded by spectacular achievements in cosmological CMB research. The pedagogical reviews and technical seminars included in this volume represent most of the important current topics in S-Z work and in the astrophysics of clusters. The publication touches upon all relevant aspects of the S-Z effect and its use as a precise cluster and cosmological probe. To commemorate the 40th anniversary of the detection of the CMB by Penzias and Wilson (in 1964), there is a chapter devoted to the history of this discovery. In his fascinating account of their work, he outlines also some lessons pertinent to current scientific issues. Other chapters discuss very interesting related observational work in Europe and the US.
Download or read book The Dark Matter Effect on the Scaling Relations written by Chiara Marmo and published by . This book was released on 2003 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cosmological Physics written by J. A. Peacock and published by Cambridge University Press. This book was released on 1999 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and authoritative introduction to contemporary cosmology for advanced undergraduate and graduate students.
