Download or read book Cosmological Parameter Estimation Using SZ selected Galaxy Cluster Abundances written by Jonathan Dudley and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The observational record of the growth of structure in the universe over cosmic time offers a unique and invaluable cosmological measure. The abundance and evolutionary history of structure in the universe are dependent upon the parameters which define the cosmological framework. In this work, we formulate a method for deriving cosmological constraints from the observed abundance of galaxy clusters. These objects are the most massive gravitationally collapsed structures in the universe and act as tracers of the underlying density field. We develop a technique for comparing theoretical cluster abundances with observed galaxy cluster catalogs. In this process, we explore and constrain the parameter space for departures from the canonical cosmological model. The motivation and framework for this investigation are presented in the opening chapters. An introduction to modern cosmological theory and methods for calculating theoretical galaxy cluster abundances are presented. A description of the physical observables associated with galaxy clusters follows, including a summary of detection methods. A cluster likelihood, defined through comparisons between observed cluster abundances with those predicted from theory, is developed.The focus of this work rests in the analysis of the cluster likelihood. The fiducial LCDM model is explored and parameter constraints are presented. The cluster dataset is shown to provide useful constraints on numerous parameters and the inclusion of supplementary data is investigated. The cluster-scale normalization parameter sigma_8 is well-constrained by this analysis, where we find sigma_8=0.745+-0.082 when considering only the cluster data and sigma_8=0.796+-0.026 for a combination of cluster and complementary datasets. The normalization of the scaling relation between the cluster observable and its mass and redshift is also constrained by this joint analysis such that, when compared with predictions from numerical simulations, we find A_SZ, meas./A_SZ, fid.=0.82+-0.17. Also explored are two extensions to the standard cosmological model, a non-cosmological-constant form of dark energy and non-Gaussian primordial fluctuations. In both cases the cluster likelihood is demonstrated to provide informative constraints, demonstrating consistency with a cosmological constant form of dark energy and Gaussian primordial fluctuations. Through a combination of cluster and complementary datasets we constrain the dark energy equation of state parameter to be w=-1.07+-0.12. The degree of non-Gaussianity inferred from a catalog of massive galaxy clusters is also constrained, finding f_NL=-36 (-491+456) at 68% confidence for a particular non-Gaussian model." --

Download or read book Cosmological Parameter Estimation from Optically Selected Cluster Catalogs written by Eduardo Rozo and published by . This book was released on 2006 with total page 204 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 Mass Calibration and Cosmological Analysis of the SPT SZ Galaxy Cluster Sample Using Velocity Dispersion sigma V and X ray Y X Measurements written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we present a velocity-dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg2 of the survey along with 63 velocity dispersion ([sigma]v) and 16 X-ray YX measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. Our method accounts for cluster selection, cosmological sensitivity, and uncertainties in the mass calibrators. The calibrations using [sigma]v and YX are consistent at the 0.6[sigma] level, with the [sigma] v calibration preferring ~16% higher masses. We use the full SPTCL data set (SZ clusters+[sigma]v+YX) to measure [sigma]8([Omega]m/0.27)0.3 = 0.809 ± 0.036 within a flat [Lambda]CDM model. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming that the sum of the neutrino masses is m[nu] = 0.06 eV, we find the data sets to be consistent at the 1.0[sigma] level for WMAP9 and 1.5[sigma] for Planck+WP. Allowing for larger [Sigma]m[nu] further reconciles the results. When we combine the SPTCL and Planck+WP data sets with information from baryon acoustic oscillations and Type Ia supernovae, the preferred cluster masses are 1.9[sigma] higher than the YX calibration and 0.8[sigma] higher than the [sigma] v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness-of-fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe data set, we measure [Omega]m = 0.299 ± 0.009 and [sigma]8 = 0.829 ± 0.011. Within a [nu]CDM model we find [Sigma]m[nu] = 0.148 ± 0.081 eV. We present a consistency test of the cosmic growth rate using SPT clusters. Allowing both the growth index [gamma] and the dark energy equation-of-state parameter w to vary, we find [gamma] = 0.73 ± 0.28 and w = -1.007 ± 0.065, demonstrating that the e[Sigma]xpansion and the growth histories are consistent with a [Lambda]CDM universe ([gamma] = 0.55; w = -1).

Download or read book Fundamental Parameters in Cosmology written by J. Thanh Van Tran and published by Atlantica Séguier Frontières. This book was released on 1998 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book End to end Cluster Cosmology Constraining Cosmological Parameters with X ray Selected Galaxy Clusters written by Jethro Venn Ridl and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cosmological Parameters and the Evolution of the Universe written by Katsuhiko Sato and published by Springer Science & Business Media. This book was released on 1999-01-31 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: How old is our Universe? At what speed is our Universe expanding? Is our universe flat or curved? How is the hierarchical structure of the present Universe formed? The purpose of IAU Symposium 183 on the Cosmological Parameters and the Evolution of the Universe was to encourage a state-of-the-art discussion and assessment of cosmology by putting together the latest observational data and theoretical ideas on the evolution of the universe and cosmological parameters. In this volume, excellent reviews on these subjects by distinguished scientists are included. The first article by M.S. Longair, `Cosmological Parameters and the Evolution of the Universe: Progress and Prospect', is a magnificent general review which can be understood by non-specialists. The other reviews include Hubble Constants (W.L. Freedman, G.A. Tammann), Microwave Background Radiation (R.B. Partridge, N. Sugiyama), Galaxy Formation and Evolution (R.S. Ellis) and Alternative Cosmological Models (J.V. Narlikar). In addition to the reviews, recent observational and theoretical developments by outstanding active scientists are included.

Download or read book Cosmology with Clusters of Galaxies written by Sandor Mihaly Molnar and published by Nova Science Publishers. This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive review of the methods applied to derive cosmological parameters for a given model and test different cosmological models using the most massive collapsed structures in our Universe: clusters of galaxies. Clusters typically consist of hundreds of galaxies and high-temperature ionised gas trapped in their gravitational field dominated by dark matter extending out to 2-3 Mpc. The formation, evolution, and structure of these massive rare objects are sensitive probes of the assumed cosmology. This is a multidisciplinary field of astrophysics involving multi-wavelength observations, gravity theory, atomic physics, plasma physics, magneto-hydrodynamics, astrophysical cosmology and numerical simulations. Our understanding of the physics of clusters, which is essential when using them for cosmology, has been improved tremendously due to the recent advent of technology and observational strategy in multi-frequency observations, and enhanced by improved numerical simulations made possible by more advanced high performance computers. As a result of these developments, cosmology with clusters of galaxies has become a mature discipline recently, and provided an important contribution to establish our concordance cosmological constant dominated cold dark matter model. In the near future we expect a rapid expansion of this field due to results from new cluster surveys and multi-wavelength observations. This timely volume on this exciting newly established field discusses galaxy cluster physics and provides a detailed description of using clusters to derive cosmological parameters applying accurate measurements of individual clusters as well as using clusters as a statistical tool. A detailed discussion is given on degeneracies between derived parameters and the systematic effects, which are becoming a limiting factor. An account for using clusters to test different cosmological models is also presented. This volume provides an introduction to galaxy cluster cosmology for physics and astronomy graduate students and serves as a reference source for professionals.

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 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 Particle Physics At The Year Of Light Proceedings Of The Seventeenth Lomonosov Conference On Elementary Particle Physics written by Alexander I Studenikin and published by World Scientific. This book was released on 2017-04-17 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: The volume of these proceedings is devoted to a wide variety of items, both in theory and experiment, of particle physics such as electroweak theory, fundamental symmetries, tests of the standard model and beyond, neutrino and astroparticle physics, hadron physics, gravitation and cosmology, physics at the present and future accelerator.

Download or read book Clusters of Galaxies Physics and Cosmology written by Andrei M. Bykov and published by Springer. This book was released on 2020-10-31 with total page 535 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 Statistics of the Galaxy Distribution written by Vicent J. Martinez and published by CRC Press. This book was released on 2001-12-20 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last decade, statisticians have developed new statistical tools in the field of spatial point processes. At the same time, observational efforts have yielded a huge amount of new cosmological data to analyze. Although the main tools in astronomy for comparing theoretical results with observation are statistical, in recent years, cosmologis

Download or read book Gravitational Waves and Cosmology written by E. Coccia and published by IOS Press. This book was released on 2020-08-31 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past twenty years have seen a number of breakthroughs in astrophysics and cosmology, some of which have been awarded Nobel prizes. These physics triumphs highlight the fact that while students need a solid grounding in the fundamentals of astrophysics and cosmology, sight of the basics of the fundamental interactions in physics must not be lost. This book presents papers based on lectures given at the 200th Course of the International School of Physics “Enrico Fermi”, on Gravitation and Cosmology, held in Varenna, Italy, from 3 - 12 July 2017. The aim of the school was to expose students to state-of-the-art research in the field of gravitational waves and cosmology, from both a theoretical and experimental point of view. Lectures were organized in such a way as to foster interaction between the two communities, and a wide range of topics was addressed. In the gravitational waves section, topics covered include experimental issues connected with gravitational wave detection and the new field of multi-messenger astronomy, as well as more astrophysical aspects. In the section on cosmology, there are contributions on the early universe, on the cosmic microwave background (CMB) and on redshift surveys. Other areas covered include a review of inflationary scenarios; the non-Gaussian features of primordial density fluctuations; and the physical mechanisms responsible for the spectral distortions of the blackbody spectrum of the CMB. The book provides an overview of important research developments and will be of interest to all students of gravitation and cosmology.

Download or read book Cosmological Constraints from Galaxy Clusters in the 2500 Square degree SPT SZ Survey written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: (Abridged) We present cosmological constraints obtained from galaxy clusters identified by their Sunyaev-Zel'dovich effect signature in the 2500 square degree South Pole Telescope Sunyaev Zel'dovich survey. We consider the 377 cluster candidates identified at z>0.25 with a detection significance greater than five, corresponding to the 95% purity threshold for the survey. We compute constraints on cosmological models using the measured cluster abundance as a function of mass and redshift. We include additional constraints from multi-wavelength observations, including Chandra X-ray data for 82 clusters and a weak lensing-based prior on the normalization of the mass-observable scaling relations. Assuming a LCDM cosmology, where the species-summed neutrino mass has the minimum allowed value (mnu = 0.06 eV) from neutrino oscillation experiments, we combine the cluster data with a prior on H0 and find sigma_8 = 0.797+-0.031 and Omega_m = 0.289+-0.042, with the parameter combination sigma_8(Omega_m/0.27)^0.3 = 0.784+-0.039. These results are in good agreement with constraints from the CMB from SPT, WMAP, and Planck, as well as with constraints from other cluster datasets. Adding mnu as a free parameter, we find mnu = 0.14+-0.08 eV when combining the SPT cluster data with Planck CMB data and BAO data, consistent with the minimum allowed value. Finally, we consider a cosmology where mnu and N_eff are fixed to the LCDM values, but the dark energy equation of state parameter w is free. Using the SPT cluster data in combination with an H0 prior, we measure w = -1.28+-0.31, a constraint consistent with the LCDM cosmological model and derived from the combination of growth of structure and geometry. When combined with primarily geometrical constraints from Planck CMB, H0, BAO and SNe, adding the SPT cluster data improves the w constraint from the geometrical data alone by 14%, to w = -1.023+-0.042.

Download or read book Fourteenth Marcel Grossmann Meeting The On Recent Developments In Theoretical And Experimental General Relativity Astrophysics And Relativistic Field Theories Proceedings Of The Mg14 Meeting On General Relativity In 4 Parts written by Massimo Bianchi and published by World Scientific. This book was released on 2017-10-13 with total page 4784 pages. Available in PDF, EPUB and Kindle. Book excerpt: The four volumes of the proceedings of MG14 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 35 morning plenary talks over 6 days, 6 evening popular talks and 100 parallel sessions on 84 topics over 4 afternoons.Volume A contains plenary and review talks ranging from the mathematical foundations of classical and quantum gravitational theories including recent developments in string theory, to precision tests of general relativity including progress towards the detection of gravitational waves, and from supernova cosmology to relativistic astrophysics, including topics such as gamma ray bursts, black hole physics both in our galaxy and in active galactic nuclei in other galaxies, and neutron star, pulsar and white dwarf astrophysics.The remaining volumes include parallel sessions which touch on dark matter, neutrinos, X-ray sources, astrophysical black holes, neutron stars, white dwarfs, binary systems, radiative transfer, accretion disks, quasars, gamma ray bursts, supernovas, alternative gravitational theories, perturbations of collapsed objects, analog models, black hole thermodynamics, numerical relativity, gravitational lensing, large scale structure, observational cosmology, early universe models and cosmic microwave background anisotropies, inhomogeneous cosmology, inflation, global structure, singularities, chaos, Einstein-Maxwell systems, wormholes, exact solutions of Einstein's equations, gravitational waves, gravitational wave detectors and data analysis, precision gravitational measurements, quantum gravity and loop quantum gravity, quantum cosmology, strings and branes, self-gravitating systems, gamma ray astronomy, cosmic rays and the history of general relativity.

Download or read book Cosmological Parameter Estimation from Galaxy Surveys written by Daniel Burkey and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: