Download or read book Galaxy Cluster Cosmology with the Atacama Cosmology Telescope written by Matthew Hasselfield and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Atacama Cosmology Telescope written by and published by . This book was released on 2011 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present constraints on cosmological parameters based on a sample of Sunyaev-Zeldovich-selected galaxy clusters detected in a millimeter-wave survey by the Atacama Cosmology Telescope. The cluster sample used in this analysis consists of 9 optically-confirmed high-mass clusters comprising the high-significance end of the total cluster sample identified in 455 square degrees of sky surveyed during 2008 at 148GHz. We focus on the most massive systems to reduce the degeneracy between unknown cluster astrophysics and cosmology derived from SZ surveys. We describe the scaling relation between cluster mass and SZ signal with a 4-parameter fit. Marginalizing over the values of the parameters in this fit with conservative priors gives? = 0.851 ± 0.115 and w = -1.14 ± 0.35 for a spatially-flat wCDM cosmological model with WMAP 7-year priors on cosmological parameters. This gives a modest improvement in statistical uncertainty over WMAP 7-year constraints alone. Fixing the scaling relation between cluster mass and SZ signal to a fiducial relation obtained from numerical simulations and calibrated by X-ray observations, we find?8 = 0.821 ± 0.044 and w = -1.05 ± 0.20. These results are consistent with constraints from WMAP 7 plus baryon acoustic oscillations plus type Ia supernoava which give?8 = 0.802 ± 0.038 and w = -0.98 ± 0.053. A stacking analysis of the clusters in this sample compared to clusters simulated assuming the fiducial model also shows good agreement. These results suggest that, given the sample of clusters used here, both the astrophysics of massive clusters and the cosmological parameters derived from them are broadly consistent with current models.

Download or read book Toward a Mass limited Catalog of Galaxy Clusters from the Atacama Cosmology Telescope written by Adam Douglas Hincks and published by . This book was released on 2009 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of the Sunyaev Zel dovich Galaxy Clusters from the Atacama Cosmology Telescope written by David M. Holtz and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimizing Future CMB Observatories and Measuring Galaxy Cluster Motions with the Atacama Cosmology Telescope written by Patricio Andres Gallardo Matamala and published by . This book was released on 2019 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmic Microwave Background (CMB) experiments are a great tool to probe the universe's history and content. In the recent decade, great progress in large format detector array technologies has allowed increased sensitivity and sky coverage, which has enabled very precise measurements. The next generation of CMB experiments will offer larger focal planes, which will allow measurements with exquisite precision. In this thesis, the following studies are presented: The development of a silicon meta-material deep reactive ion etched anti-reflection coating for use in sub-millimeter wavelengths. Characterization of the aliased detector noise performance of the Atacama Cosmology Telescope (ACT), a current polarization sensitive six-meter telescope that observes the CMB at arcminute resolution. Optical models developed to describe the pickup and sidelobes characteristics of the ACT. These models are currently being used to optimize the design of the Simons Observatory, a next generation six-meter telescope with increased sensitivity. Studies of the motions of clusters of galaxies via the pairwise kinetic Sunyaev-Zeldovich effect (the frequency-distortion of the cold CMB light due to the interaction with the hot inter-cluster ionized gas), with data from ACT.

Download or read book The Atacama Cosmology Telescope written by Cristóbal Javier Sifón Andalaft and published by . This book was released on 2012 with total page 52 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 Measuring the Growth of Structure with Multi wavelength Surveys of Galaxy Clusters written by and published by . This book was released on 2008 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current and near-future galaxy cluster surveys at a variety of wavelengths are expected to provide a promising way to obtain precision measurements of the growth of structure over cosmic time. This in turn would serve as an important precision probe of cosmology. However, to realize the full potential of these surveys, systematic uncertainties arising from, for example, cluster mass estimates and sample selection must be well understood. This work follows several different approaches towards alleviating these uncertainties. Cluster sample selection is investigated in the context of arcminute-resolution millimeter-wavelength surveys such as the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). Large-area, realistic simulations of the microwave sky are constructed and cluster detection is simulated using a multi-frequency Wiener filter to separate the galaxy clusters, via their Sunyaev-Zel'dovich signal, from other contaminating microwave signals. Using this technique, an ACT-like survey can expect to obtain a cluster sample that is 90% complete and 85% pure above a mass of 3 x 10^14 Msun. Cluster mass uncertainties are explored by comparing X-ray and weak-lensing mass estimates for shear-selected galaxy clusters in the Deep Lens Survey (DLS) to study possible biases in using cluster baryons or weak-lensing shear as tracers of the cluster total mass. Results are presented for four galaxy clusters that comprise the top-ranked shear-selected system in the DLS, and for three of these clusters there is agreement between X-ray and weak-lensing mass estimates. For the fourth cluster, the X-ray mass estimate is higher than that from weak-lensing by 2-sigma, and X-ray images suggest this cluster may be undergoing a merger with a smaller cluster, which may be biasing the X-ray mass estimate high. The feasibility of measuring galaxy cluster peculiar velocities using an ACT-like instrument is also investigated. Such a possibility would allow one to measure structure growth via large-scale velocity fields and circumvent the uncertainties associated with measuring cluster masses. We show that such measurements are possible and yield statistical uncertainties of roughly 100 km/sec given either a temperature prior with 1-sigma errors of less than 2 keV or additional lower frequency millimeter-band observations.

Download or read book Cosmological Probes of Light Relics written by Benjamin Wallisch and published by Springer Nature. This book was released on 2019-11-20 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The wealth of recent cosmic microwave background and large-scale structure data has transformed the field of cosmology. These observations have not only become precise enough to answer questions about the universe on the largest scales, but also to address puzzles in the microscopic description of Nature. This thesis investigates new ways of probing the early universe, the properties of neutrinos and the possible existence of other light particles. In particular, based on detailed theoretical insights and novel analyses, new evidence for the cosmic neutrino background is found in the distribution of galaxies and in cosmic microwave background data. This tests the Standard Model of particle physics and the universe back to a time when it was about one second old. Furthermore, it is demonstrated that future observations will be capable of probing physics beyond the Standard Model since they can achieve a particular target which would either allow the detection of any light particles that have ever been in thermal equilibrium or imply strong bounds on their properties.

Download or read book The XMM BCS Galaxy Cluster Survey written by and published by . This book was released on 2011 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The XMM-Newton - Blanco Cosmology Survey project (XMM-BCS) is a coordinated X-ray, optical and mid-infrared cluster survey in a field also covered by Sunyaev-Zel dovich effect (SZE) surveys by the South Pole Telescope and the Atacama Cosmology Telescope. The aim of the project is to study the cluster population in a 14 deg2 field (center: [alpha] H"23:29:18.4, [delta] H"-54:40:33.6). The uniform multi-wavelength coverage will also allow us for the first time to comprehensively compare the selection function of the different cluster detection approaches in a single test field and perform a cross-calibration of cluster scaling relations. In this work, we present a catalog of 46 X-ray selected clusters from the initial 6 deg2 survey core. We describe the XMM-BCS source detection pipeline and derive physical properties of the clusters. We provide photometric redshift estimates derived from the BCS imaging data and spectroscopic redshift measurements for a low redshift subset of the clusters. The photometric redshift estimates are found to be unbiased and in good agreement with the spectroscopic values. Our multi-wavelength approach gives us a comprehensive look at the cluster and group population up to redshifts z H"1. The median redshift of the sample is 0.47 and the median mass M500 H"1 x 1014 M{sub {circle_dot}} (H"2 keV). From the sample, we derive the cluster log N - log S using an approximation to the survey selection function and find it in good agreement with previous studies. We compare optical mass estimates from the Southern Cosmology Survey available for part of our cluster sample with our estimates derived from the X-ray luminosity. Weak lensing masses available for a subset of the cluster sample are in agreement with our estimates. Optical masses based on cluster richness and total optical luminosity are found to be significantly higher than the X-ray values. The present results illustrate the excellent potential of medium-deep, X-ray surveys to deliver cluster samples for cosmological modelling. In combination with available multi-wavelength data in optical, near-infrared and SZE, this will allow us to probe the dependence of the selection functions on relevant cluster observables and provide thus an important input for upcoming large-area multi-wavelength cluster surveys.

Download or read book Cosmology from Galaxy Clusters with Cosmic Microwave Background Lensing Mass Calibration written by Íñigo Zubeldía Lafuente and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Growth of Massive Galaxies and Clusters at High Redshift written by Robert Raymond Lindner and published by . This book was released on 2013 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Massive galaxies and galaxy clusters gain much of their mass by merging with their neighbors; this hierarchical structure formation is the foundation of our understanding of galaxy evolution. Nevertheless, the detailed evolutionary processes needed to form the structures we see in the local Universe remain poorly understood. This thesis comprises four projects examining the growth of galaxies and clusters at high redshift by using radio, sub/millimeter, and X-ray observations to provide empirical constraints on their cosmic evolution. Chapter 2 presents deep 1.2mm imaging of the inner 20' x 20' of the Lockman Hole North (LHN) field to search for submillimeter galaxies (SMGs), rapidly star-forming, high-redshift galaxy mergers. We detect 41 SMGs with S/N>4.0 and use Monte Carlo simulations to estimate their number counts and angular clustering properties. Chapter 3 investigates the nuclear accretion properties of the LHN SMGs. In the sample's average rest-frame X-ray spectrum, we detect strong Fe K alpha emission (equivalent width EW>=1 keV) from highly-ionized Fe species -- evidence that beneath the galaxies' heavy obscuration, supermassive black holes may be growing rapidly. Chapter 4 describes a new 345 GHz and 2.1 GHz imaging campaign to study the intracluster media (ICM) of eleven massive Sunyaev Zel'dovich Effect (SZE)-detected clusters from the Atacama Cosmology Telescope (ACT) southern survey. In six of eleven, 345 GHz SZE increments are detected and used to characterize the spatial distribution and energy content of the ICM at high (19.2") resolution. This work helps us understand how SZE-mass scaling relations are affected by contamination from other sources along the line of sight and by dynamical properties of the ICM. Chapter 5 studies the non-thermal radio emission in one exceptional z=0.870 binary cluster merger (ACTJ0102-4915, ``El Gordo'') with the help of newly-acquired radio observations. El Gordo is the highest-redshift cluster known to host double radio ``relics'' and a radio ``halo, '' and by characterizing the morphology, intensity, spectral index, and polarization of these structures, we extend our knowledge of ICM shocks and magnetic fields to an era when the Universe was only 50% its current age.

Download or read book An Introduction to Modern Cosmology written by Andrew Liddle and published by John Wiley & Sons. This book was released on 2015-07-07 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Introduction to Modern Cosmology Third Edition is an accessible account of modern cosmological ideas. The Big Bang Cosmology is explored, looking at its observational successes in explaining the expansion of the Universe, the existence and properties of the cosmic microwave background, and the origin of light elements in the universe. Properties of the very early Universe are also covered, including the motivation for a rapid period of expansion known as cosmological inflation. The third edition brings this established undergraduate textbook up-to-date with the rapidly evolving observational situation. This fully revised edition of a bestseller takes an approach which is grounded in physics with a logical flow of chapters leading the reader from basic ideas of the expansion described by the Friedman equations to some of the more advanced ideas about the early universe. It also incorporates up-to-date results from the Planck mission, which imaged the anisotropies of the Cosmic Microwave Background radiation over the whole sky. The Advanced Topic sections present subjects with more detailed mathematical approaches to give greater depth to discussions. Student problems with hints for solving them and numerical answers are embedded in the chapters to facilitate the reader’s understanding and learning. Cosmology is now part of the core in many degree programs. This current, clear and concise introductory text is relevant to a wide range of astronomy programs worldwide and is essential reading for undergraduates and Masters students, as well as anyone starting research in cosmology. The accompanying website for this text, http://booksupport.wiley.com, provides additional material designed to enhance your learning, as well as errata within the text.

Download or read book The Atacama Cosmology Telescope written by Ryan P. Fisher and published by . This book was released on 2009 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Discovery of Cosmic Voids written by Laird A. Thompson and published by Cambridge University Press. This book was released on 2020-12-10 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The large-scale structure of the Universe is dominated by vast voids with galaxies clustered in knots, sheets, and filaments, forming a great 'cosmic web'. In this personal account of the major astronomical developments leading to this discovery, we learn from Laird A. Thompson, a key protagonist, how the first 3D maps of galaxies were created. Using non-mathematical language, he introduces the standard model of cosmology before explaining how and why ideas about cosmic voids evolved, referencing the original maps, reproduced here. His account tells of the competing teams of observers, racing to publish their results, the theorists trying to build or update their models to explain them, and the subsequent large-scale survey efforts that continue to the present day. This is a well-documented account of the birth of a major pillar of modern cosmology, and a useful case study of the trials surrounding how this scientific discovery became accepted.

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 The Large Scale Structure of the Universe written by P. J. E. Peebles and published by Princeton University Press. This book was released on 2020-09-15 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: The classic account of the structure and evolution of the early universe from Nobel Prize–winning physicist P. J. E. Peebles An instant landmark on its publication, The Large-Scale Structure of the Universe remains the essential introduction to this vital area of research. Written by one of the world's most esteemed theoretical cosmologists, it provides an invaluable historical introduction to the subject, and an enduring overview of key methods, statistical measures, and techniques for dealing with cosmic evolution. With characteristic clarity and insight, P. J. E. Peebles focuses on the largest known structures—galaxy clusters—weighing the empirical evidence of the nature of clustering and the theories of how it evolves in an expanding universe. A must-have reference for students and researchers alike, this edition of The Large-Scale Structure of the Universe introduces a new generation of readers to a classic text in modern cosmology.