Download or read book Weak Lensing Analysis of the Canada France Imaging Survey written by Axel Guinot and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among the big questions cosmology faces today, the nature of dark matter and dark energy are at the center of upcoming surveys. The future stage IV missions Euclid and LSST will cover a surface on the sky never reached before to unveil structures at very large scales and different epochs. Weak gravitational lensing will be one of the cosmological probes used to trace dark matter. Gravitational lensing is a physical phenomenon which uses the distortion of light to trace the presence of mass in the Universe. The interesting point of weak lensing is its sensitivity to total mass, i.e. baryonic and non-baryonic. Due to gravitational lensing, distant galaxies will appear distorted on the observed images. The measurement of the distortions induced by gravitational shear requires a very accurate estimation of the shape of galaxies. This thesis will present the data reduction pipeline built for weak lensing studies, from the telescope to cosmological parameter inference. The work focuses on the analysis of the Canada-France Imaging Survey (CFIS), a u- and r-band survey covering 5,000 deg2 in the Northern hemisphere. The high resolution and depth of those data make it one the best survey candidates for weak lensing science to date. Among other things, accurate measurement of the shape galaxies requires a very good knowledge of the PSF for which a suite of validation tests have been developed. Due to the noise, and approximations used in the shape measurement, the results can be biased. The residual multiplicative and additive biases have been reduced to m
Download or read book Probing Cosmic Dark Matter and Dark Energy with Weak Gravitational Lensing Statistics written by Masato Shirasaki and published by Springer. This book was released on 2015-11-18 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book the applicability and the utility of two statistical approaches for understanding dark energy and dark matter with gravitational lensing measurement are introduced. For cosmological constraints on the nature of dark energy, morphological statistics called Minkowski functionals (MFs) to extract the non-Gaussian information of gravitational lensing are studied. Measuring lensing MFs from the Canada–France–Hawaii Telescope Lensing survey (CFHTLenS), the author clearly shows that MFs can be powerful statistics beyond the conventional approach with the two-point correlation function. Combined with the two-point correlation function, MFs can constrain the equation of state of dark energy with a precision level of approximately 3–4 % in upcoming surveys with sky coverage of 20,000 square degrees. On the topic of dark matter, the author studied the cross-correlation of gravitational lensing and the extragalactic gamma-ray background (EGB). Dark matter annihilation is among the potential contributors to the EGB. The cross-correlation is a powerful probe of signatures of dark matter annihilation, because both cosmic shear and gamma-ray emission originate directly from the same dark matter distribution in the universe. The first measurement of the cross-correlation using a real data set obtained from CFHTLenS and the Fermi Large Area Telescope was performed. Comparing the result with theoretical predictions, an independent constraint was placed on dark matter annihilation. Future lensing surveys will be useful to constrain on the canonical value of annihilation cross section for a wide range of mass of dark matter annihilation. Future lensing surveys will be useful to constrain on the canonical value of annihilation cross section for a wide range of mass of dark matter.
Download or read book Gravitational Lensing Strong Weak and Micro written by Peter Schneider and published by Springer Science & Business Media. This book was released on 2006-12-30 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observation, in 1919 by A.S. Eddington and collaborators, of the gra- tational de?ection of light by the Sun proved one of the many predictions of Einstein’s Theory of General Relativity: The Sun was the ?rst example of a gravitational lens. In 1936, Albert Einstein published an article in which he suggested - ing stars as gravitational lenses. A year later, Fritz Zwicky pointed out that galaxies would act as lenses much more likely than stars, and also gave a list of possible applications, as a means to determine the dark matter content of galaxies and clusters of galaxies. It was only in 1979 that the ?rst example of an extragalactic gravitational lens was provided by the observation of the distant quasar QSO 0957+0561, by D. Walsh, R.F. Carswell, and R.J. Weymann. A few years later, the ?rst lens showing images in the form of arcs was detected. The theory, observations, and applications of gravitational lensing cons- tute one of the most rapidly growing branches of astrophysics. The gravi- tional de?ection of light generated by mass concentrations along a light path producesmagni?cation,multiplicity,anddistortionofimages,anddelaysp- ton propagation from one line of sight relative to another. The huge amount of scienti?c work produced over the last decade on gravitational lensing has clearly revealed its already substantial and wide impact, and its potential for future astrophysical applications.
Download or read book Astrophysical Applications of Gravitational Lensing written by Evencio Mediavilla and published by Cambridge University Press. This book was released on 2016-10-06 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravitational lenses offer the best, and sometimes the only, means of tackling key problems in many fields of astrophysics and cosmology. According to Einstein's theory, the curvature of light-rays increases with mass; gravitational lenses can be used to map the distribution of mass in a Universe in which virtually all matter is dark matter of an unknown nature. Gravitational lensing has significantly improved our knowledge of many astrophysical phenomena, such as exoplanets, galaxies, active galactic nuclei, quasars, clusters, large-scale structure and the Universe itself. All these topics are covered fully in this book, together with two tutorials on lens and microlensing modelling. The future of lensing in relation to large surveys and the anticipated discoveries of thousands more gravitational lenses is also discussed, making this volume an ideal guide for postgraduate students and practising researchers in the use of gravitational lenses as a tool in their investigations.
Download or read book New Horizons for Observational Cosmology written by A. Cooray and published by IOS Press. This book was released on 2015-01-06 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our understanding of the universe has been revolutionized by observations of the cosmic microwave background, the large-scale structure of the universe, and distant supernovae. These studies have shown that we are living in a strange universe: 96% of the present day energy density of the universe is dominated by so-called dark matter and dark energy. But we still do not know what dark matter and dark energy actually are. This book presents lectures from the 186th Course in the Enrico Fermi International School of Physics entitled New Horizons for Observational Cosmology, held in Varenna, Italy, in July 2013. Topics covered at this school included: cosmic microwave background anisotropies; galaxy clustering; weak lensing; dark energy; dark matter; inflation; modified gravity; neutrino physics; reionization; galaxy formation; and first stars. The anticipated release of Planck data at the end of 2014 will provide a more complete view of temperature anisotropy of the cosmic microwave background, and the reporting of other important results is also expected soon. These new data will undoubtedly address fundamental questions about the universe. This book prepares the ground for future work which may answer some of these exciting questions.
Download or read book Dark Matter And Cosmic Web Story Second Edition written by Jaan Einasto and published by World Scientific. This book was released on 2024-04-29 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concepts of dark matter and the cosmic web are some of the most significant developments in cosmology in the past century. They have decisively changed the classical cosmological paradigm, which was first elaborated upon during the first half of the 20th century but ran into serious problems in the second half. Today, they are integral parts of modern cosmology, which explains everything from the Big Bang to inflation to the large-scale structure of the Universe.Dark Matter and Cosmic Web Story describes the contributions that led to a paradigm shift from the Eastern point of view. It describes the problems with the classical view, the attempts to solve them, the difficulties encountered by those solutions, and the conferences where the merits of the new concepts were debated. Amidst the science, the story of scientific work in a small country occupied by the Soviet Union and the tumultuous events that led to its breakup are detailed as well.The development of cosmology has often treated as a West-East conflict between the American school led by Jim Peebles in Princeton and the Soviet team led by Yakov Zeldovich in Moscow. Actually, the development of ideas was broader, and a certain role played the Tartu team. The Tartu cosmology school was founded by Ernst Öpik and has its own traditions and attitude to science. In the new edition of the book the interplay between three cosmology schools is written in more detail. The recent development of dark matter and cosmic web studies is described, as well as the evolution of global properties of the cosmic web.This book is accompanied by a website which contains additional material: copies of the originals of some crucial papers, astronomical movies, and movies which showcase the private life of the author. In this second edition, two chapters on the statistical description of the cosmic web and its development were added, as well as chapter on the sociology of science. To keep the length of this book reasonable, a lot of reorganisation of the text has been done as well.
Download or read book Reviews in astronomy and space sciences written by Christopher H. K. Chen and published by Frontiers Media SA. This book was released on 2024-05-24 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Issues in Astronomy and Astrophysics 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 2981 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in Astronomy and Astrophysics / 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Astronomy and Astrophysics. The editors have built Issues in Astronomy and Astrophysics: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Astronomy and Astrophysics in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in Astronomy and Astrophysics: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Modified Gravity Progresses And Outlook Of Theories Numerical Techniques And Observational Tests written by Baojiu Li and published by World Scientific. This book was released on 2019-10-10 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modified gravity theories have been a main focus of theoretical cosmology research in the past decade or so, and have been quickly developing into a mature research field that attracts attention, interest and effort from both theoretical and observational cosmologists. To be prepared for fully exploiting the future observational data, and to provide a guidance for people who are new to this field, it is useful to have a comprehensive review to summarise the current state of knowledge and to foresee the future developments.This book presents expert reviews on different topics in the field, which are then coordinated and organised in a self-consistent and self-contained manner. It is suitable for graduate students and researchers interested in the frontier research of gravity theories.
Download or read book Testing New Weak Lensing Measurement Techniques with the Dark Energy Survey written by Christina Irene Krawiec and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we first present an analysis on the effect of wind at the Blanco Telescope, the home of the Dark Energy Camera (DECam), on Dark Energy Survey (DES) image quality. We find it to have a likely negligible impact on the weak gravitational lensing measurements conducted with images taken during high wind. We then present the methods and validation of two new techniques in weak lensing shear and magnification measurement. We demonstrate highly accurate recovery of weak gravitational lensing shear using an implementation of the Bayesian Fourier Domain (BFD) method, proposed by Bernstein and Armstrong (2014), extended to correct for selection biases. The BFD formalism is rigorously correct for Nyquist-sampled, background-limited, uncrowded image of background galaxies. We conduct initial tests of this code on ≈109 simulated lensed galaxy images and recover the simulated shear to a fractional accuracy of m = (2.1 [plus/minus] 0.4) × 10-3 , substantially more accurate than has been demonstrated previously for any generally applicable shear measurement method. We also introduce a new Bayesian method for selecting high-redshift galaxies and calculating their magnification around foreground lenses. We apply this method to galaxies from DES Science Verification (SV).Finally, we share the results of a survey conducted with DES collaborators on the collaboration itself, in which we find positive attitudes towards education and public outreach (EPO) in physics and astronomy. We also provide recommendations for current and future surveys on how to increase EPO engagement by scientists.
Download or read book Astronomy and Astrophysics written by and published by . This book was released on 2007 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cosmological Physics with Gravitational Lensing written by J. Thanh Van Tran and published by . This book was released on 2001 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1997 Part 1 written by Astronomisches Rechen-InstitutARI and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1746 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts is devoted to the recording, summarizing and indexing of astronomical publications throughout the world. Two volumes are scheduled to appear per year. Volume 67 records 10,903 papers covering besides the classical fields of astronomy and astrophysics such matters as space flights related to astronomy, lunar and planetary probes and satellites, meteorites and interplanetary matter, X rays and cosmic rays, quasars and pulsars. The abstracts are classified under more than one hundred subject categories thus permitting quick surveying of the bulk of material published on the same topic within six months. For instance, this volume records 119 papers on minor planets, 155 papers on supernovae, and 554 papers on cosmology.
Download or read book Outskirts of Galaxies written by Johan H. Knapen and published by Springer. This book was released on 2017-07-09 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of invited reviews written by world-renowned experts on the subject of the outskirts of galaxies, an upcoming field which has been understudied so far. These regions are faint and hard to observe, yet hide a tremendous amount of information on the origin and early evolution of galaxies. They thus allow astronomers to address some of the most topical problems, such as gaseous and satellite accretion, radial migration, and merging. The book is published in conjunction with the celebration of the end of the four-year DAGAL project, an EU-funded initial training network, and with a major international conference on the topic held in March 2016 in Toledo. It thus reflects not only the views of the experts, but also the scientific discussions and progress achieved during the project and the meeting. The reviews in the book describe the most modern observations of the outer regions of our own Galaxy, and of galaxies in the local and high-redshift Universe. They tackle disks, haloes, streams, and accretion as observed through deep imaging and spectroscopy, and guide the reader through the various formation and evolution scenarios for galaxies. The reviews focus on the major open questions in the field, and explore how they can be tackled in the future. This book provides a unique entry point into the field for graduate students and non-specialists, and serves as a reference work for researchers in this exciting new field.
Download or read book Galaxy Evolution Connecting the Distant Universe with the Local Fossil Record written by Monique Spite and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: This up-to-date review of the basic elements directly connected to the evolution of galaxies links data about remote galaxies to the observation of very old populations in our own galaxy. Young researchers and well-known specialists discuss the difficulties and remaining uncertainties of the problem.
Download or read book The Journal of the Royal Astronomical Society of Canada written by Royal Astronomical Society of Canada and published by . This book was released on 1998 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Library catalogue in 1911" (31 p.) appended to v. 4.
Download or read book Annual Report written by Canada-France-Hawaii Telescope Corporation and published by . This book was released on 2009 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
