Download or read book Halo Models of Large Scale Structure written by Asantha Cooray and published by . This book was released on 2002 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of Halo Approach to Non Linear Large Scale Structure written by Asantha Cooray and published by LAP Lambert Academic Publishing. This book was released on 2010-06 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present astrophysical applications of the recently popular halo model to describe large scale structure clustering. We formulate the power spectrum, bispectrum and trispectrum of dark matter density field in terms of correlations within and between dark matter halos. The halo approach uses results from numerical simulations and involves a profile for dark matter, a mass function for halos, and a description of halo biasing with respect to the linear density field. This technique can easily be extended to describe clustering of any property of the large scale structure, such as galaxies, baryons and pressure, provided that one formulate the relationship between such properties and dark matter. We discuss applications of the halo model for several observational probes of the local universe involving weak gravitational lensing, thermal Sunyaev-Zel dovich (SZ) effect and the kinetic SZ effect. With respect to weak gravitational lensing, we study the generation of non-Gaussian signals which are potentially observable in galaxy shear data. We study the three and four-point statistics, specifically the bispectrum and trispectrum, of the convergence using the dark matter halo approach.
Download or read book The Large Scale Structures written by Stéphane Ilić and published by Springer. This book was released on 2014-06-13 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark Energy and Dark Matter are among the greatest mysteries in modern cosmology. The present work explores in depth how large cosmic structures can help us unveil the nature of these components of the Universe. One the one hand, it focuses on a signature that Dark Energy imprints on the Cosmic Microwave Background through its impact on the time-evolution of gravitational potentials: the integrated Sachs-Wolfe (iSW) effect. Another cosmological background, the Cosmic Infrared Background, is considered for the first time in the study of the iSW effect and demonstrated to be a highly efficient and promising tracer. Changing the perspective on the problem, the use of superstructures for iSW detection is then extensively reviewed: using precise solutions to Einstein’s general relativity equations, the full iSW effect is computed, especially due to the cosmic voids predicted by the theory. Using measurements from the most recent data, it is subsequently shown how the iSW probes the solidity of the cosmological standard model. On the topic of Dark Matter, an original study is presented, showing that temperature measurements of the intergalactic medium shed light on the nature of Dark Matter particles, providing the tightest constraints on their decay properties.
Download or read book The Halo Void dust Model of Large Scale Structure written by Rodrigo Voivodic and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure Formation in the Universe written by T. Padmanabhan and published by Cambridge University Press. This book was released on 1993 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text provides an up-to-date and pedagogical introduction to this exciting area of research.
Download or read book The Halo Void dust Model of Large Scale Structure written by R. Voivodic 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 Large Scale Structure Tracks And Traces Proceedings Of 12th Potsdam Cosmology Workshop written by Volker Muller and published by World Scientific. This book was released on 1998-08-08 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the largest physical structures in the universe is essential for the comprehension of the cosmos as a whole. We want to know how our world is formed, what it is made of and how it evolves.Galaxies, as the most visible constituents of the universe, are interesting probes for the cosmic time sequence. Their formation and development provides us with unique clues to the cosmic evolution. This is tightly connected with the hierarchical cosmic structure: groups and clusters of galaxies and their embedding into the large scale structure offer the opportunity to study the dependencies.Galaxy redshift surveys delineate most impressively a large cosmic web, which is composed of sheets and filaments. Grand simulations of the cosmic evolution complement these observations from the theoretical side and allow one quantify and compare various model universes.Quasar absorption line studies, gravitational lensing and even the X-ray background radiation provide important quantitative measures of the history of matter clustering. Finally, the microwave radiation traces very early structures, which are supposed to originate in the phase of inflationary expansion shortly after the big bang.This volume constituting the proceedings of the 12th Potsdam Cosmology Workshop, deals with the basic aspects of cosmological structure formation on the largest physical scales.
Download or read book Large Scale Structure and Motions in the Universe written by Marino Mezzetti and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1980's have been times of great excitement in Astrophysics and Cosmology. Professors Dennis Sciama and Fabio Mardirossian and all the other Members of the Organizing Committees are to be congratulated for having given us a taste of this excitement in Trieste, by inviting the leaders of the subject to the meeting they have organized. The excitement has corne from the new observations of the three-dimensional structure of the universe through a large number of new measurements of redshifts. These have revealed that clusters of galaxies are distributed on the surface of big empty bubbles of diameters of the order of 20-50 Mpc. Additionally, there is some evidence for invisible dark matter (whose composition is not known) as well as evidence for the gravitational lens effect. To cap this has corne the supernova of 1987, an event which last occurred 383 years ago. For the first time in history, the neutrino flux from the supernova was measured, giving limits to neutrino masses and numbers of neutrino types. (The dark matter problem is related to Particle Physics - beyond this standard model). It is good to be alive when all this happens and to try to comprehend this. Once again, our appreciation to the organisers and to those who presented their beautiful results.
Download or read book The Role of Halo Substructure in Gamma Ray Dark Matter Searches written by Miguel A. Sánchez-Conde and published by MDPI. This book was released on 2020-05-28 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important, open research topic today is to understand the relevance that dark matter halo substructure may have for dark matter searches. In the standard cosmological model, halo substructure or subhalos are predicted to be largely abundant inside larger halos, for example, galaxies such as ours, and are thought to form first and later merge to form larger structures. Dwarf satellite galaxies—the most massive exponents of halo substructure in our own galaxy—are already known to be excellent targets for dark matter searches, and indeed, they are constantly scrutinized by current gamma-ray experiments in the search for dark matter signals. Lighter subhalos not massive enough to have a visible counterpart of stars and gas may be good targets as well, given their typical abundances and distances. In addition, the clumpy distribution of subhalos residing in larger halos may boost the dark matter signals considerably. In an era in which gamma-ray experiments possess, for the first time, the exciting potential to put to test the preferred dark matter particle theories, a profound knowledge of dark matter astrophysical targets and scenarios is mandatory should we aim for accurate predictions of dark matter-induced fluxes for investing significant telescope observing time on selected targets and for deriving robust conclusions from our dark matter search efforts. In this regard, a precise characterization of the statistical and structural properties of subhalos becomes critical. In this Special Issue, we aim to summarize where we stand today on our knowledge of the different aspects of the dark matter halo substructure; to identify what are the remaining big questions, and how we could address these; and, by doing so, to find new avenues for research.
Download or read book Interpreting New Galaxy Large scale Structure Measurements and the Galaxy Halo Connection written by Angela Marie Berti and published by . This book was released on 2020 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The galaxy distribution in the joint space of stellar mass and star formation rate (SFR) is observed to be bimodal, with distinct star-forming (high SFR) and quiescent (low SFR) populations across many orders of magnitude in stellar mass. The absence of a significant population of intermediate-stage galaxies implies that galaxies tend to cease star formation and become quiescent relatively rapidly, and the physical origins of this rapid quenching are an open question in the field of galaxy evolution. Recent progress in cosmological simulations of dark matter structure evolution, as well as in statistical modeling of how galaxies inhabit dark matter halos, suggest a nuanced coevolutionary relationship between galaxies and the dark matter halos galaxies reside in (the "galaxy-halo connection"), in which the statistical galaxy content of a halo depends on more than halo mass. One class of these galaxy-halo connection models are those that incorporate galaxy assembly bias, a general term for the dependence of galaxy properties on halo properties other than mass. For example, distinct stellar-to-halo mass relations for star-forming and quiescent central galaxies is a form of galaxy assembly bias that could manifest as an anticorrelation of galaxy SFR with clustering amplitude, if the trend is independent of stellar (or halo) mass. In this dissertation we present the first measurements of galactic conformity, or the tendency of neighboring galaxies to share the star formation properties of an adjacent central galaxy, on two-halo scales beyond the local universe (to z~1). We then measure the clustering of isolated galaxies as a proxy for central galaxies, separately for star-forming and quiescent galaxies, to test predictions of galaxy-halo models reflecting galaxy assembly bias. Finally, we measure the joint dependence of clustering on stellar mass and SFR. With mock galaxy catalogs derived from simulations and an empirical galaxy evolution model we quantify and compensate for the effects of systematic biases on these measurements. A parallel theme of this dissertation is demonstrating how existing galaxy surveys beyond the local universe are at the cusp of probing the volumes needed for statistically significant tests of theoretical predictions of various models of galaxy evolution.
Download or read book Generation of Cosmological Large Scale Structure written by David N. Schramm and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volwne is the proceedings of the third school in particle astrophysics that Schramm and Galeotti have organized at Erice. The focus of thirs third school was the Generation of Cosmological Large-Scale Structure. It was held in November of 1996. The fIrst school in the series was on "Gauge Theory and the Early Universe" in May 1986, the second was on "Dark Matter in the Universe" in May 1988. All three schools have been successful under the auspices of the NATO Advanced Study Institute. This volume is thus the third in the series of the proceedings of these schools. The choice of the topic for this third school was natural, since the problem of generating a large-scale structure has become the most pressing problem in cosmology today. In particular, it is this generation of structure that is the interface between astronomical observations and particle models for the early universe. To date, all models for generating structures inevitably require new fundamental physics beyond the standard, SU x SU X U , model of high energy physics. The 3 2 I seeds for generating structures usually invoke unifIcation physics, and the matter needed to clump and form them seems to require particle properties that have not been seen in laboratories to date.
Download or read book A Course in Cosmology written by Dragan Huterer and published by Cambridge University Press. This book was released on 2023-02-28 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new graduate textbook adopts a pedagogical approach to contemporary cosmology that enables readers to build an intuitive understanding of theory and data, and of how they interact, which is where the greatest advances in the field are currently being made. Using analogies, intuitive explanations of complex topics, worked examples and computational problems, the book begins with the physics of the early universe, and goes on to cover key concepts such as inflation, dark matter and dark energy, large‐scale structure, and cosmic microwave background. Computational and data analysis techniques, and statistics, are integrated throughout the text, particularly in the chapters on late-universe cosmology, while another chapter is entirely devoted to the basics of statistical methods. A solutions manual for end-of-chapter problems is available to instructors, and suggested syllabi, based on different course lengths and emphasis, can be found in the Preface. Online computer code and datasets enhance the student learning experience.
Download or read book Structure Formation in Modified Gravity Cosmologies written by Alexandre Barreira and published by Springer. This book was released on 2016-05-03 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique thesis covers all aspects of theories of gravity beyond Einstein’s General Relativity, from setting up the equations that describe the evolution of perturbations, to determining the best-fitting parameters using constraints like the microwave background radiation, and ultimately to the later stages of structure formation using state-of-the-art N-body simulations and comparing them to observations of galaxies, clusters and other large-scale structures. This truly ground-breaking work puts the study of modified gravity models on the same footing as the standard model of cosmology. Since the discovery of the accelerating expansion of the Universe, marked by the awarding of the 2011 Nobel Prize in Physics, there has been a growing interest in understanding what drives that acceleration. One possible explanation lies in theories of gravity beyond Einstein’s General Relativity. This thesis addresses all aspects of the problem, an approach that is crucial to avoiding potentially catastrophic biases in the interpretation of upcoming observational missions.
Download or read book Simulating Large Cosmology Surveys with Calibrated Halo Models written by Stuart Lynn and published by . This book was released on 2011 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis I present a novel method for constructing large scale mock galaxy and halo catalogues and apply this model to a number of important topics in modern cosmology. Traditionally such mocks are created through first evolving a high resolution particle simulation from a set of initial conditions to the present epoch, identifying bound structures and their evolution, and finally applying a semi-analytic prescription for galaxy formation. In contrast to this computationally expensive procedure, I use low resolution simulations to obtain a density field that traces large scale modes. From this background I sample the population statistics of halos: the number of halos which are typically found within a region of a given overdensity, to produce a halo catalogue. From the halo catalogue I then produce galaxies by appealing to the halo model. In this model the expected number of galaxies within a halo and the distribution of their properties is dependent on halo mass alone. By sampling conditional luminosity functions for a number of populations of galaxies, I produce a galaxy catalogue with luminosity and colour properties. The aim of developing algorithm is not to probe the mechanics of galaxy formation in great detail. It is instead intended as a method of rapidly producing mock galaxy and halo catalogues rapidly on modern desktop computers. The approach we will take is to try to distill the minimal algorithm required to achieve this and still provide useful catalogues for observational cosmologists. Both the conditional mass function and conditional luminosity functions required for the algorithm are calibrated from the Millennium Simulation, one of the highest resolution cosmology simulations to date, and its associated semi-analytic catalogues. In Chapter 2 I examine these statistics and provide fits to the quantities of interest. As a test of the method, in Chapter 3 I produce a halo and galaxy catalogue from the same large scale modes as the Millennium Simulation. The clustering statistics of galaxies and halos within this re-simulation are calculated and compared with those of the original. Con dent of the accuracy of the method, in Chapter 4 I populate a number of simulations, each 8 times the volume of the Millennium Simulation, and study the evolution of the Baryon Acoustic Oscillation signal. For each population (dark matter, halos and galaxies) I fit the BAO in the power spectrum to obtain the shift in the BAO peak. In Chapter 5 I extend the algorithm to produce lightcones: simulated skies in which the evolution of the Universe along the line of sight is accounted for. I simulate the geometry and limitations of a major pending survey and calculate the expected clustering signature I expect to see in both. The redshift space distortions induced by peculiar velocities of galaxies along the line of sight are determined and their ability to distinguish between gravity models is also explored. In Chapter 6 I detail a further extension to the algorithm for simulating weak gravitational lensing surveys. I use the analytic 2D surface density pro files of NFW profiles to dress each dark matter halo on a lightcone. The sum of these pro files over the entire population can be used to construct high resolution maps of the convergence. From these maps I calculate the spectrum of the convergence and compare with theoretical predictions. Finally in Chapter 7 I discuss further possible applications and extensions of the algorithm I have developed in this thesis.
Download or read book Cosmological Inflation and Large Scale Structure written by Andrew R. Liddle and published by Cambridge University Press. This book was released on 2000-04-13 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thorough and up-to-date graduate textbook on the most promising theory of the universe - inflationary cosmology.
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 The Large Scale Structure of the Universe written by Malcolm S. Longair and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: The significance of the present IAU symposium, "The Large Scale Structure of the Universe", fortunately requires no elaboration by the editors. The quality of the wide range of observational and theoretical astrophysics contained in this volume speaks for itself. The published version of the proceedings contains all the contributions presented at the symposium with the exception of the introductory lecture by V. A. Ambartsumian. Contributed papers, short contributions and discussions have been included according to the recommendations of the IAU. Many people contributed to the success of the symposium. First of all, thanks are due to the USSR Academy of Sciences and to the Estonian Academy of Sciences for sponsoring this symposium in Tallinn. The efforts of Academician K. Rebane, President of the Estonian Academy of Sciences, are particularly appreciated. The astronomical hosts of the symposium were the members of the W. Struve Astrophysical Observatory of Tartu who made outstanding efforts to lavish participants with Estonian hospitality which was greatly appreciated and enjoyed by them and their guests. The members of the Scientific and Local Organising Committees are listed below and we thank all of them for their contributions which were central to the success of the symposium. In addition are listed members of the Technical Organising Committee who were responsible for all details of the organisation and whose vigilance ensured that all aspects of the symposium ran smoothly and efficiently. Their contributions are all gratefully acknowledged.
