Download or read book Shapes and Orientations of Dark Matter Halos written by Brandon A. Allgood and published by . This book was released on 2005 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shapes Of Galaxies And Their Dark Halos The Proceedings Of The Yale Cosmology Workshop written by Priyamvada Natarajan and published by World Scientific. This book was released on 2002-03-28 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the proceedings of a very topical workshop aimed at understanding the shapes of the baryonic and dark matter components of galaxies. Several groups presented their recent results from observations and numerical N-body simulations.
Download or read book The shape of dark matter halos written by Robert Paul Olling and published by . This book was released on 1995 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Shapes of Galaxies and Their Dark Halos written by Priyamvada Natarajan and published by World Scientific. This book was released on 2002 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the proceedings of a very topical workshop aimed at understanding the shapes of the baryonic and dark matter components of galaxies. Several groups presented their recent results from observations and numerical N-body simulations.
Download or read book Einstein s Telescope The Hunt for Dark Matter and Dark Energy in the Universe written by Evalyn Gates and published by W. W. Norton & Company. This book was released on 2010-02-22 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In Einstein’s Telescope, Evalyn Gates, an expert on all that’s dark in the universe, brings dark matter, dark energy, and even black holes to light." —Neil deGrasse Tyson, astrophysicist, American Museum of Natural History, and New York Times best-selling author of Astrophysics for People in a Hurry In 1936, Albert Einstein predicted that gravitational distortions would allow space itself to act as a telescope far more powerful than humans could ever build. Now, cosmologists at the forefront of their field are using this radical technique ("Einstein’s Telescope") to detect the invisible. In fresh, engaging prose, astrophysicist Evalyn Gates explains how this tool is enabling scientists to uncover planets as big as the Earth, discover black holes as they whirl through space, and trace the evolution of cosmic architecture over billions of years. Powerful and accessible, Einstein’s Telescope takes us to the brink of a revolution in our understanding of the deepest mysteries of the Universe.
Download or read book Can Lensing Measure the Shape of Dark Matter Halos written by Uzair Hussain and published by . This book was released on 2012 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this project was to explore the shapes of dark matter halos using high resolution N-body simulations. One of the main aspects explored was how well the shape can be measured through weak lensing. T.
Download or read book Dark Matter Halos and Stellar Kinematics of Elliptical Galaxies written by Jeremy David Murphy and published by . This book was released on 2012 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: The hierarchical assembly of mass, wherein smaller clumps of dark matter, stars, gas, and dust buildup over time to form the galaxies we see today in the local Universe through accretion events with other clumps, is a central tenet of galaxy formation theory. Supported by theoretically motivated simulations, and observations of the distribution of galaxies over a large range of redshift, the theory of hierarchical growth is now well established. However, on the scales of individual galaxies, hierarchical growth struggles to explain a number of observations involving the amount and distribution of dark matter in galaxies, and the timescale of both the formation of stars, and the assembly of those stars into galaxies. In this dissertation I attempt to address some of the central issues of galaxy formation. My work focuses on massive elliptical galaxies and employs the orbit-based, axisymmetric dynamical modeling technique of Schwarzschild to constrain the total mass of a galaxy to large radii. From this starting point a determination of the extent and shape of the dark matter halo profile is possible and can then be compared to the results of simulations of the formation of galaxies. These dynamical models include information on the stellar orbital structure of the galaxy, and can be used as a further point of comparison with N-body simulations and observations from other groups. Dynamical modeling results for both M49 and M87, the first and second rank galaxies in the Virgo Cluster, are presented and compared in Chapters 4 and 2 respectively. Although both galaxies are similar in mass, a closer analysis shows they exhibit very different dark matter halo profiles and stellar orbital structure, and likely followed very different formation pathways. My primary dataset comes from observations carried out on the Mitchell Spectrograph (formally VIRUS-P) at McDonald Observatory.\footnote{The instrument's name was changed over the last year. As some of this work was originally written when the instrument was named VIRUS-P, I have elected to use that name in those sections of this dissertation (Chapters 2 and 5). In Chapters 3, 4, and 6, I use the current name.} The Mitchell Spectrograph is a fiber-fed integral field spectrograph, and allows one to collect spectra at many positions on a galaxy simultaneously. With spectroscopy one is able to not only constrain the kinematics of the stars, but also their integrated chemical abundances. In the introduction I describe recent work I have carried out with my collaborators using the Mitchell Spectrograph to add further constraints to our picture of galaxy formation. In that work we find that the cores of massive elliptical galaxies have been in place for many billions of years, and had their star formation truncated at early times. The stars comprising their outer halos, however, come from less massive systems. Yet unlike the stars of present day, low-mass galaxies, whose star formation is typically extended, these accreted systems had their star formation shut off at high redshift. Although our current sample is relatively small, these observations place a rigid constraint on the timescale of galaxy assembly and indicate the important role of minor mergers in the buildup of the diffuse outer halos of these systems. All of these advances in our understanding of the Universe are driven, in large part, by advances in the instrumentation used to collect the data. The Mitchell Spectrograph is a wonderful example of such an advance, as the instrument has allowed for observations of the outer halo of M87 to unprecedented radial distances (Chapter 3). A significant component of my dissertation research has been focused on characterizing the fiber optics of both the Mitchell Spectrograph and the fiber optics for the VIRUS spectrograph. I cover the results of the work on the Mitchell Spectrograph optical fibers in Chapter 5. The affects of stress and motion on a fiber bundle, critical to the VIRUS spectrograph, are explored in Chapter 6.
Download or read book The Structure of Dark Matter Haloes in Cosmological Simulations written by Philip Edward Bett and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We study the angular momentum, shape and density structures of dark matter haloes using very large dark matter simulations, and use smaller, higher-resolution simulations to investigate how the distributions of these properties are changed by the physical processes associated with baryons and galaxy formation. We begin with a brief review of the necessary background theory, including the growth of cosmic structures, the origin of their angular momenta, and the techniques used to simulate galaxies, haloes and the large scale structure. In Chapter 2, we use the Millennium Simulation (MS) to investigate the distributions of the spin and shape parameters of millions of dark matter haloes. We compare results for haloes identified using three different algorithms, including one based on the branches of the halo merger trees. In addition to characterising the relationships between halo spin, shape and mass, we also study their impact on halo clustering and bias. We go on in Chapter 3 to investigate the internal angular momentum structure of dark matter haloes. We look at the radial profiles of the dark matter angular momentum in terms of both magnitude and direction, again using large-volume dark matter simulations including the MS. We then directly compare dark matter haloes simulated both with and without baryonic physics, studying how this changes the dark matter angular momentum. After relating the spin orientation of galaxies to their haloes, we consider the shape of the projected, stacked mass distribution of haloes oriented according to their central galaxy, mimicking attempts to measure halo ellipticity by weak gravitational lensing. We consider the density structure of dark matter haloes in Chapter 4. For the dark matter simulations, we focus our interest on the source of the scatter in the distribution of concentration parameters, correlating it with both the halo spin and formation time. We compare different algorithms for predicting the concentration distribution using different aspects of the merger histories. We again go on to directly compare high-resolution haloes in simulations run with and without baryons and galaxy formation, looking at how these additional physical processes transform the density profiles. Finally, we compare the circular velocity curves of the haloes simulated with galaxies to the rotation curves of observed galaxies, using the Universal Rotation Curve model.
Download or read book The orbital structure of galaxies and dark matter halos in N body simulations written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 The Orbital Structure of Galaxies and Dark Matter Halos in N body Simulatons written by Roland Jesseit and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book How Round is Your Halo written by Randall Wayth and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Particle Dark Matter written by Gianfranco Bertone and published by Cambridge University Press. This book was released on 2010-01-07 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the dark matter problem in particle physics, astrophysics and cosmology for graduate students and researchers.
Download or read book The Expected Shape of the Milky Way s Dark Matter Halo written by Jesús David Prada González and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The shape of the Dark Matter (DM) structure (halo) in which a galaxy is embedded is heavily determined by the anisotropic accretion of mass from its specific environment. Therefore, the shape of a galaxy-s halo is an important feature to inquire about its formation history and the relation of DM and gas within it. In this work we study the shape of the DM halo of Milky Way-like galaxies from the Auriga simulations. We focus on the radial and time dependence. We found that, on DM-only and Magneto-hydrodynamic (MHD) simulations, the shape of the DM halo is more triaxial in the inner-skirts than in the outter-skirts. We compared simulations with and without gas and verified that the presence of visible matter has an effect of rounding the DM halo which is amplified for smaller radii, where the gravitational potential of the galactic disk becomes more significant. Regarding the effect of time...
Download or read book Lessons from the Local Group written by Kenneth Freeman and published by Springer. This book was released on 2014-11-13 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our understanding of galaxy formation comes mostly from two sources: sensitive observations at high angular resolution of the high-redshift Universe, where galaxies are observed to be forming, and detailed observations of individual stars and clouds in the Local Group, where telltale remnants from its formative time remain and similar processes operate at a low level today. The current conference focusses on key aspects of the Local Group, composed of the Milky Way, Andromeda and Triangulum Spiral Galaxies, the Large and Small Magellanic Cloud galaxies, numerous dwarf and irregular galaxies, and intergalactic gas. Topics include the halo and thick disk of the Milky Way with its first stars and stellar streams; the Milky Way bar, bulge and outer edge; interstellar dust and turbulence; star formation processes and stellar scattering in spiral arms; views through the infrared Eyes of the Spitzer Space Telescope; globular clusters; the Local Gould Belt; stellar metallicities and elemental abundances; the environment and black hole in the Milky Way nucleus; orbits of the Magellanic Clouds and galaxy dwarfs; interstellar dust and turbulence; the outer disks and halos of the Andromeda and Triangulum galaxies; ripples from a collision in Andromeda; and arcs of carbon stars in the Triangulum and intergalactic clouds. This volume also discusses surveys of planetary nebulae, galaxy morphology at low and high redshift, cosmic evolution of star and galaxy formation and gas accretion, Lyman alpha emitting galaxies, ultra-low surface brightness imaging, and more. Readers are given a clear and comprehensive view of this wide range of topics written by specialists in each field. This is the proceedings of an International Conference at the Seychelles archipelago in May 2014, on the occasion of the 60th birthday of David Block and the millionth (base two) birthday of Bruce Elmegreen.
Download or read book The Dark Matter Halo Shape of Edge on Disk Galaxies written by Jess Clare O'Brien and published by . This book was released on 2007 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt:
