Galactic Halos PDF Download

Author: Dennis Zaritsky
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 480

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Author: Charalabos K. Terzides
Publisher:
ISBN:
Category :
Languages : en
Pages : 172

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Author: Richard Morris
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 216

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Morris draws on a multitude of startling new discoveries and theories in the field of cosmology and tackles 10 of the longest-standing and most captivating problems in all of science. Cosmic Questions offers clear explanations of the best current answers to each question.

Author: Nikos Prantzos
Publisher: Springer Science & Business Media
ISBN: 9401151164
Category : Science
Languages : en
Pages : 324

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The present volume, the fourth one in the "Space Sciences Series of ISSI" (Inter national Space Science Institute), contains the proceedings of a workshop on "Pri mordial Nuclei and Their Galactic Evolution", which was held at ISSI in Bern on 6-10 May 1997. This topic was chosen following some general enquiries with the scientific community concerning its desirability and timeliness. Five convenors, D. Duncan, C. Hogan, J. Linsky, N. Prantzos, and H. Reeves (chair) subsequently set up the workshop, nominated a list of invitees, structured the workshop into a series of introductory talks and into six topical working groups (early Universe extragalactic objects -low-Z stars - galactic disk and galactic evolution - solar nebula -local interstellar medium), and described the tasks of the working groups in a list of keywords. It is the main task of ISSI to bring together space scientists, ground-based observers, and theorists from different fields and to give them the opportunity to discuss and compare their results, thus contributing to the achievement of a deeper understanding, adding value to those results through multi-disciplinary research in an atmosphere of international co-operation. In that spirit the convenors selected participants working in fields ranging from Big Bang theory to observers oftoday's Solar System, thus spanning the widest possible range both in time and space.

Author: Miguel A. Sánchez-Conde
Publisher: MDPI
ISBN: 3039360442
Category : Mathematics
Languages : en
Pages : 220

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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.

Author: R. Beck
Publisher: Springer Science & Business Media
ISBN: 9780792307044
Category : Science
Languages : en
Pages : 582

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This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.

Author: J. Val Blain
Publisher: Nova Publishers
ISBN: 9781594542435
Category : Science
Languages : en
Pages : 272

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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.

Author: Shoken M. Miyama
Publisher: Springer Science & Business Media
ISBN: 9401147809
Category : Science
Languages : en
Pages : 457

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These are the proceedings of international conference on Numerical As trophysics 1998 (NAP98), held at National Olympic Memorial Youth Cen ter, in Tokyo, Japan in the period of March 10 - 13, 1998, and hosted by the National Astronomical Observatory, Japan (NAOJ). In the last decade numerical simulations have grown up as a major tool for astrophysics. Numerical simulations give us invaluable informa tion on complex systems and physical processes under extreme conditions which can be neither realized by experiments nor directly observed. Super computers and special purpose computers may work as very large telescopes and special purpose telescopes for theoretical astrophysics, respectively. Nu merical astrophysics ranks with other tool-oriented astronomy such as ra dio astronomy, infrared astronomy, ultraviolet astronomy, X-ray astronomy, and ')'-ray astronomy. This conference, NAP98, was planned to explore recent advances in astrophysics aided by numerical simulations. The subjects of the confer ence included the large-scale structure formation, galaxy formation and evolution, star and planets formation, accretion disks, jets, gravitational wave emission, and plasma physics. NAP98 had also sessions on numerical methods and computer science. The conference was attended by 184 sci entists from 21 countries. We enjoyed excellent talks, posters, videos, and discussions: there are 40 oral presentations, 96 posters and 16 video pre sentations. We hope that these proceedings and accompanying CD-ROM replay the friendly but inspiring atmosphere of the conference.

Author: Sandra M. Faber
Publisher: Springer Science & Business Media
ISBN: 1461247624
Category : Science
Languages : en
Pages : 475

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It is sometimes said that astronomy is the crossroads of physics. In the same spirit, it can forcefully be argued that galaxies are the crossroads of astronomy. Internal pro ces ses within galaxies involve all of the fundamental components of astrophysics: stellar evolution, star formation, low-density astrophysics, dynamics, hydrodynamics, and high-energy astrophysics. Indeed, one can hardly name an observational datum in any wavelength range on any kind of celestial object that does not provide a useful clue to galaxy formation and evolution. Although internal processes in galaxies until recently occupied most of our attention, we now know that it is also vital to relate galaxies to their environment. How galaxies congregate in larger structures and are in turn influenced by them are crucial questions for galactic evolution. On a grander level we have also come to regard galaxies as the basic building blocks of the universe, the basic units whereby the large scale structure of the universe is apprehended and quantified. On a grander level still, we also believe strongly that galaxies are the direct descendents of early density irregularities in the Big Bang. Galaxy properties are now viewed as providing a crucial constraint on the physics of the Big Bang and a vital link between the macroscopic and microscopic structure of the universe.

Author: Space Telescope Science Institute (U.S.)
Publisher:
ISBN:
Category : Astronomy
Languages : en
Pages : 192

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