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Author: Markus Weber
Publisher: Sudwestdeutscher Verlag Fur Hochschulschriften AG
ISBN: 9783838123851
Category :
Languages : en
Pages : 188
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Book Description
This thesis considers the dark matter (DM) density distribution of the Milky Way. The DM is assumed to consist of weakly interacting massive particles. Their density distribution is constrained by astronomical observations. An important constraint is the so-called rotation curve (RC) of the Milky Way, which describes the rotation speed of matter around the Galactic centre as function of Galactocentric distance. It is shown that a ringlike DM component in the Galactic disc is necessary to describe the peculiar dips in the RC at 3 and 9 kpc from the centre in agreement with the dip in the gas flaring of the Milky Way. This substructure effects the local DM density which is of crucial importance for direct DM search experiments. The slight GeV excess in the spectra of diffuse Galactic gamma rays of the EGRET and Fermi satellite data are consistent with this DM density distribution, if this excess is attributed to DM annihilation.
Author: Markus Weber
Publisher: Sudwestdeutscher Verlag Fur Hochschulschriften AG
ISBN: 9783838123851
Category :
Languages : en
Pages : 188
Get Book Here
Book Description
This thesis considers the dark matter (DM) density distribution of the Milky Way. The DM is assumed to consist of weakly interacting massive particles. Their density distribution is constrained by astronomical observations. An important constraint is the so-called rotation curve (RC) of the Milky Way, which describes the rotation speed of matter around the Galactic centre as function of Galactocentric distance. It is shown that a ringlike DM component in the Galactic disc is necessary to describe the peculiar dips in the RC at 3 and 9 kpc from the centre in agreement with the dip in the gas flaring of the Milky Way. This substructure effects the local DM density which is of crucial importance for direct DM search experiments. The slight GeV excess in the spectra of diffuse Galactic gamma rays of the EGRET and Fermi satellite data are consistent with this DM density distribution, if this excess is attributed to DM annihilation.
Author: Markus Josef Weber
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: J. Val Blain
Publisher: Nova Publishers
ISBN: 9781594542435
Category : Science
Languages : en
Pages : 272
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Book Description
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: J. Val Blain
Publisher: Nova Publishers
ISBN: 9781594542480
Category : Dark matter (Astronomy)
Languages : en
Pages : 242
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Book Description
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 Ù) is less than unity. If the universe is closed, Ù is greater than unity. For the case where Ù is exactly equal to one the universe is "flat". This new book details leading-edge research from around the globe.
Author: Minos Axenides
Publisher: World Scientific
ISBN: 9814474789
Category : Science
Languages : en
Pages : 704
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Book Description
This volume is the latest in a prominent biannual series of scientific meetings on the exciting research topics of dark matter and, more recently, of dark energy. It contains a state-of-the-art update on detection efforts by experimental groups around the world trying to pin down exotic new forms of matter under the names of axions, neutralinos, wimps, primordial black holes, q balls, sterile neutrinos, as well as a tantalizing new form of dark energy component called phantom energy and quintessence. The book is self-contained as it also includes general reviews on recent cosmological observations — supernovae measurements, cosmic matter distribution surveys and cosmic radiation anisotropies — introducing even the uninitiated reader to this fascinating frontier of research.
Author: John N. Bahcall
Publisher: World Scientific
ISBN: 9812567186
Category : Science
Languages : en
Pages : 246
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Book Description
If standard gravitational theory is correct, then most of the matterin the universe is in an unidentified form which does not emit enoughlight to have been detected by current instrumentation. This book isthe second editon of the lectures given at the 4th Jerusalem WinterSchool for Theoretical Physics, with new material added. The lecturesare devoted to the missing matter problem in the universe, thesearch to understand dark matter. The goal of this volume is to makecurrent research work on unseen matter accessible to students withoutprior experience in this area and to provide insights for experts inrelated research fields. Due to the pedagogical nature of the originallectures and the intense discussions between the lecturers and thestudents, the written lectures included in this volume often containtechniques and explanations not found in more formal journalpublications.
Author: J. Val Blain
Publisher: Nova Publishers
ISBN: 9781594545498
Category : Science
Languages : en
Pages : 166
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Book Description
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 Ù) is less than unity. If the universe is closed, Ù is greater than unity. For the case where Ù is exactly equal to one the universe is "flat". This new book details leading-edge research from around the globe.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 16
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Book Description
The dark matter lumps (or "halos") that contain galaxies have locations in the Universe that are to some extent random with respect to the overall matter distributions. We investigate how best to estimate the total matter distribution from the locations of the halos. We derive the weight function w(M) to apply to dark-matter haloes that minimizes the stochasticity between the weighted halo distribution and its underlying mass density field. The optimal w(M) depends on the range of masses of halos being used. While the standard biased-Poisson model of the halo distribution predicts that bias weighting is optimal, the simple fact that the mass is comprised of haloes implies that the optimal w(M) will be a mixture of mass-weighting and bias-weighting. In N-body simulations, the Poisson estimator is up to 15× noisier than the optimal. Optimal weighting could make cosmological tests based on the matter power spectrum or cross-correlations much more powerful and/or cost effective.
Author: Paul S Wesson
Publisher: World Scientific
ISBN: 9814470007
Category : Science
Languages : en
Pages : 236
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Book Description
To the eyes of the average person and the trained scientist, the night sky is dark, even though the universe is populated by myriads of bright galaxies. Why this happens is a question commonly called Olbers' Paradox, and dates from at least 1823. How dark is the night sky is a question which preoccupies astrophysicists at the present. The answer to both questions tells us about the origin of the universe and the nature of its contents — luminous galaxies like the Milky Way, plus the dark matter between them and the mysterious dark energy which appears to be pushing everything apart. In this book, the fascinating history of Olbers' Paradox is reviewed, and the intricate physics of the light/dark universe is examined in detail. The fact that the night sky is dark (a basic astronomical observation that anybody can make) turns out to be connected with the finite age of the universe, thereby confirming some event like the Big Bang. But the space between the galaxies is not perfectly black, and data on its murkiness at various wavelengths can be used to constrain and identify its unseen constituents.
Author: Marc S. Seigar
Publisher: Morgan & Claypool Publishers
ISBN: 1681741180
Category : Science
Languages : en
Pages : 71
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Book Description
The study of dark matter, in both astrophysics and particle physics, has emerged as one of the most active and exciting topics of research in recent years. This book reviews the history behind the discovery of missing mass (or unseen mass) in the Universe, and ties this into the proposed extensions to the Standard Model of Particle Physics (such as Supersymmetry), which were being proposed within the same time frame. This book is written as an introduction to these problems at the forefront of astrophysics and particle physics, with the goal of conveying the physics of dark matter to beginning undergraduate majors in scientific fields. The book goes onto describe existing and upcoming experiments and techniques, which will be used to detect dark matter either directly on indirectly.
