Download or read book Cosmology and the Galaxy matter Connection Using Weak Gravitational Leasing Cross correlations in the Dark Energy Survery written by Judit Prat Martí and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: En aquesta tesi hem fet servir dades del Dark Energy Survey per estudiar l'evolució i continguts de l'Univers. El Dark Energy Survey (DES) ha construït un mapa de galàxies que cobreix un vuitè del cel, mesurant les posicions i distàncies de centenars de milions de galàxies, amb l'objectiu d'entendre les causes de l'expansió accelerada de l'Univers, fet que ha estat confirmat observacionalment. Entre els mecanismes que podrien causar aquesta expansió accelerada hi ha l'energia del buit associada a una constant cosmològica, una altra forma d'energia fosca, o una modificació de la generalitat general. Amb mapes de galàxies com DES, aspirem a poder distingir entre aquestes possibilitats mesurant el creixement d'estructures i la geometria de l'Univers en funció del temps.En aquesta tesi utilitzem lents gravitacionals febles per contribuir a aquest objectiu final amb mesures del Dark Energy Survey. El fenomen de lents gravitacionals es produeix quan la llum d'objectes llunyans es desvia a causa de la presència d'una distribució de massa més propera a nosaltres que corba l'espai-temps. En particular, el fenomen de lents gravitacionals febles, que només pot ser mesurat de forma estadística, ha emergit com una de les mesures més potents de la cosmologia, ja que és sensible tant a la geometria de l'Univers com a la història del creixement d'estructures, i és la tècnica principal que s'utilitza en aquesta tesi. Específicament, hem utilitzat correlacions creuades entre una font de llum al fons, ja siguin galàxies llunyanes o el fons còsmic de microones, i les posicions de galàxies en primer pla, que serveixen d'indicadors de les grans estructures de l'Univers que estan produint l'efecte de lent gravitacional. Per una banda, hem fet servir la sensitivitat d'aquestes correlacions creuades a la història del creixement d'estructures i a la geometria de l'Univers per mesurar els paràmetres cosmològics, en combinació amb altres mesures. D'altra banda, ja que aquestes correlacions creuades també són sensibles a la relació entre la matèria bariònica (visible) que forma les galàxies i el subjacent camp gravitacional produït per la matèria (majoritàriament fosca), hem pogut mesurar l'anomenat \textit{galaxy bias}, que encapsula aquesta relació entre galàxies i matèria.
Download or read book Bulletin of the Atomic Scientists written by and published by . This book was released on 1961-05 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
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 An Investigation of Cosmological Dark Matter Using Weak Gravitational Lensing written by R. Michael Jarvis and published by . This book was released on 2002 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Distribution of the Galaxies written by William C. Saslaw and published by Cambridge University Press. This book was released on 2000 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: This topical volume examines one of the leading problems in astronomy - how galaxies cluster in our Universe. This book, first published in 2000, describes gravitational theory, computer simulations and observations related to galaxy distribution functions. It embeds distribution functions in a broader astronomical context, including other exciting contemporary topics such as correlation functions, fractals, bound clusters, topology, percolation and minimal spanning trees. Key results are derived and the necessary gravitational physics provided to ensure the book is self-contained. Throughout the book, theory, computer simulation and observation are carefully interwoven and critically compared. The book also shows how future observations can test the theoretical models for the evolution of galaxy clustering at early times in our Universe. This clear and authoritative volume is written at a level suitable for graduate students, and will be of key interest to astronomers, cosmologists, physicists and applied statisticians.
Download or read book Accelerated Cosmic Expansion written by Claudia Moreno González and published by Springer Science & Business Media. This book was released on 2013-11-29 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings from the 2012 Fourth International Meeting on Gravitation and Cosmology, focusing on accelerated cosmic expansion This volume provides both an update and a review of the state of alternative theories of gravity in connection with the accelerated expansion of the universe issue. Different theoretical proposals exist to explain the acceleration in the cosmic expansion, generating the dark energy issue and opening the possibility to theories of gravity alternative to general relativity. Related issues such as the dark matter problem are also surveyed in order to give the readers profound insight on the subject from different points of view. Comprised of short talks and plenary lectures given by leading experts in the field, some of them with brilliant and historic contributions, the book allows the reader to find readable and referenced surveys in topics like f(R) theories, the dark matter and dark energy issues, Modified Newtonian Dynamics (MOND) scenarios, f(T) theories, scalar-tensor theories derived from non-Riemannian geometries, emergent universes, the cosmological constant and other topics of current interest for younger and senior physicists and graduate students. These proceedings are from the Fourth International Meeting on Gravitation and Cosmology, held in Guadalajara, Jalisco, México, from 20 - 25 May, 2012, was sponsored by ICTP- Trieste, Italy and COECyTJAL-Universidad de Guadalajara, México. This event is a series of scientific meetings started in 2004 in Cuba, focusing on current and selected topics in the fields of gravitation and cosmology.
Download or read book Progress in Dark Matter Research written by J. Val Blain and published by Nova Publishers. This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is generally believed that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the cosmic microwave background enough to form the large-scale structures that we see in the universe today. For each of the stellar, galactic, and galaxy cluster/supercluster observations the basic principle is that if we measure velocities in some region, then there has to be enough mass there for gravity to stop all the objects flying apart. Dark matter has important consequences for the evolution of the Universe and the structure within it. According to general relativity, the Universe must conform to one of three possible types: open, flat, or closed. The total amount of mass and energy in the universe determines which of the three possibilities applies to the Universe. In the case of an open Universe, the total mass and energy density (denoted by the Greek letter Omega) is less than unity. If the Universe is closed, Omega is greater than unity. For the case where Omega is exactly equal to one the Universe is "flat". This book details leading-edge research from around the globe.
Download or read book Dark Matter written by Michael Smith and published by BoD – Books on Demand. This book was released on 2022-07-06 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents several new, important explanations for dark matter, all dissimilar to the discredited subatomic particle-like but invisible matter. One chapter presents evidence that abundant cold hydrogen, baryonic matter, is the source of the missing gravity. Another chapter suggests that dark matter is better explained by stars in spiral galaxies that follow non-Keplerian orbits. A third chapter proposes that gravity attributed to dark matter is due to the sprinkling of black holes throughout galaxies, which is supported by LIGO/Virgo observations. Another chapter questions the assumptions of the Friedmann (FLRW) model, proposing a better method for handling astrophysical data. Additional chapters discuss cosmic ray propagation, axion decay, the cosmological scale factor, and the philosophical outlook of cosmologists when dealing with the questions of dark matter and dark energy.
Download or read book Sources and Detection of Dark Matter and Dark Energy in the Universe written by David B. Cline and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter research is one of the most fascinating and active fields among current high-profile scientific endeavours. It holds the key to all major breakthroughs to come in the fields of cosmology and astroparticle physics. The present volume is particularly concerned with the sources and the detection of dark matter and dark energy in the universe and will prove to be an invaluable research tool for all scientists who work in this field.
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 The Grand Unification of Dark Matters written by Dan Sharpe and published by Createspace Independent Publishing Platform. This book was released on 2017-01-01 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unifying theory that covers dark matter, dark energy, gravity, space and negative energy by means of observation, citation, and deduction, revealing a fundamental definition for both space and gravity, support of dark energy theory, explanation of dark matter, revealing additional structure and properties of baryonic atoms, and revising estimates of the longevity of the universe. Other matters discussed are aerospace, anti-gravity, artificial gravity, gravitational waves, wormholes, cold fusion, cold fission, health and wellbeing, and the earth's atmosphere and global warming. The Grand Unification of Dark Matters theory is almost a certainty at this point, but will require validation and spark significant research and advancements in the areas of physics, space, cosmology, energy, health and various applied sciences. Expand your knowledge and perception of the universe, with this exciting new theory based on 3,700 years of written history, and who knows how long mankind has recognized this raw energy of the universe as being essential to your life, health and wellbeing.
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 The Identification of Dark Matter written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interacting Dark Energy and the Expansion of the Universe written by Alexander S. Silbergleit and published by . This book was released on 2017 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kepler Problem in the Presence of Dark Energy and the Cosmic Local Flow written by Alexander Silbergleit and published by Springer Nature. This book was released on 2019-11-29 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book derives and analyzes all solutions to the Kepler problem with dark energy (DE), presenting significant results such as: (a) all radial infinite motions obey Hubble’s law at large times; (b) all orbital infinite motions are asymptotically radial and obey Hubble’s law; (c) infinite orbital motions strongly dominate the finite ones. This clearly shows the effect of repulsive DE: In the classical Kepler problem, all orbital motions are finite for negative energies and infinite in the opposite case. Another DE effect is spatial localization of bounded orbits: mostly, they are within the equilibrium sphere, where the attractive Newtonian force outbalances the repulsive force of DE. This problem is of particular current interest due to recent studies of the local flows of galaxies showing domination of DE in their dynamics; the book discusses this observation in detail.
Download or read book Groups of Galaxies in the Nearby Universe written by Ivo Saviane and published by Springer Science & Business Media. This book was released on 2007-08-01 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: For every galaxy in the field or in clusters, there are about three galaxies in groups. The Milky Way itself resides in a group. Groups in the local universe offer the chance to study galaxies in environments characterized by strong interactions. In the cosmological context, groups trace large-scale structures better than clusters; the evolution of groups and clusters appears to be related. All these aspects of research are summarized in this book.
Download or read book Computer Simulation Using Particles written by R.W Hockney and published by CRC Press. This book was released on 2021-03-24 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computer simulation of systems has become an important tool in scientific research and engineering design, including the simulation of systems through the motion of their constituent particles. Important examples of this are the motion of stars in galaxies, ions in hot gas plasmas, electrons in semiconductor devices, and atoms in solids and liquids. The behavior of the system is studied by programming into the computer a model of the system and then performing experiments with this model. New scientific insight is obtained by observing such computer experiments, often for controlled conditions that are not accessible in the laboratory. Computer Simulation using Particles deals with the simulation of systems by following the motion of their constituent particles. This book provides an introduction to simulation using particles based on the NGP, CIC, and P3M algorithms and the programming principles that assist with the preparations of large simulation programs based on the OLYMPUS methodology. It also includes case study examples in the fields of astrophysics, plasmas, semiconductors, and ionic solids as well as more detailed mathematical treatment of the models, such as their errors, dispersion, and optimization. This resource will help you understand how engineering design can be assisted by the ability to predict performance using the computer model before embarking on costly and time-consuming manufacture.
