Modeling the Affect of Dark Matter Distributions in the Milky Way on the Component of the Cosmic Rays Energy Spectrum as Incident on Earth PDF Download
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Author: Masha Kamenetska
Publisher:
ISBN:
Category :
Languages : en
Pages : 106
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Book Description
In this thesis, we investigate the effect of dark matter distribution in the galaxy on the positron spectrum on earth. We wrote code to simulate two district dark matter distribution functions as well as the annihilations which convert them into positrons. We then channeled the results into a galaxy propagation software package GALPROP and obtained a positron spectrum on earth. Our results suggest that while no dramatic differences emerge in the spectrum as a result of varying dark matter distributions, further studies are needed to confidently establish the exact nature of the relationship between the ellipticity of the dark matter profile and the positron spectrum. trajectories for other research designs are made clear as a result of this project.
Author: Masha Kamenetska
Publisher:
ISBN:
Category :
Languages : en
Pages : 106
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Book Description
In this thesis, we investigate the effect of dark matter distribution in the galaxy on the positron spectrum on earth. We wrote code to simulate two district dark matter distribution functions as well as the annihilations which convert them into positrons. We then channeled the results into a galaxy propagation software package GALPROP and obtained a positron spectrum on earth. Our results suggest that while no dramatic differences emerge in the spectrum as a result of varying dark matter distributions, further studies are needed to confidently establish the exact nature of the relationship between the ellipticity of the dark matter profile and the positron spectrum. trajectories for other research designs are made clear as a result of this project.
Author: Gregory Leonard LaScola
Publisher:
ISBN:
Category : Baryons
Languages : en
Pages : 86
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Book Description
Author: Sabino Matarrese
Publisher: Springer Science & Business Media
ISBN: 9048186854
Category : Science
Languages : en
Pages : 413
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Book Description
This book brings together reviews from leading international authorities on the developments in the study of dark matter and dark energy, as seen from both their cosmological and particle physics side. Studying the physical and astrophysical properties of the dark components of our Universe is a crucial step towards the ultimate goal of unveiling their nature. The work developed from a doctoral school sponsored by the Italian Society of General Relativity and Gravitation. The book starts with a concise introduction to the standard cosmological model, as well as with a presentation of the theory of linear perturbations around a homogeneous and isotropic background. It covers the particle physics and cosmological aspects of dark matter and (dynamical) dark energy, including a discussion of how modified theories of gravity could provide a possible candidate for dark energy. A detailed presentation is also given of the possible ways of testing the theory in terms of cosmic microwave background, galaxy redshift surveys and weak gravitational lensing observations. Included is a chapter reviewing extensively the direct and indirect methods of detection of the hypothetical dark matter particles. Also included is a self-contained introduction to the techniques and most important results of numerical (e.g. N-body) simulations in cosmology. " This volume will be useful to researchers, PhD and graduate students in Astrophysics, Cosmology Physics and Mathematics, who are interested in cosmology, dark matter and dark energy.
Author: Yasushi Muraki
Publisher:
ISBN:
Category : Cosmic rays
Languages : en
Pages : 262
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Book Description
Author: Eric C. Carlson
Publisher:
ISBN: 9781339956992
Category :
Languages : en
Pages : 673
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Book Description
Over the last decade, experiments in high-energy astroparticle physics have reached unprecedented precision and sensitivity which span the electromagnetic and cosmic-ray spectra. These advances have opened a new window onto the universe for which little was previously known. Such dramatic increases in sensitivity lead naturally to claims of excess emission, which call for either revised astrophysical models or the existence of exotic new sources such as particle dark matter. Here we stand firmly with Occam, sharpening his razor by (i) developing new techniques for discriminating astrophysical signatures from those of dark matter, and (ii) by developing detailed foreground models which can explain excess signals and shed light on the underlying astrophysical processes at hand. We concentrate most directly on observations of Galactic gamma and cosmic rays, factoring the discussion into three related parts which each contain significant advancements from our cumulative works. In Part I we introduce concepts which are fundamental to the Indirect Detection of particle dark matter, including motivations, targets, experiments, production of Standard Model particles, and a variety of statistical techniques. In Part II we introduce basic and advanced modelling techniques for propagation of cosmic-rays through the Galaxy and describe astrophysical gamma-ray production, as well as presenting state-of-the-art propagation models of the Milky Way.Finally, in Part III, we employ these models and techniques in order to study several indirect detection signals, including the Fermi GeV excess at the Galactic center, the Fermi 135 GeV line, the 3.5 keV line, and the WMAP-Planck haze.
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: Benjamin P. Burch
Publisher:
ISBN:
Category :
Languages : en
Pages : 308
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Book Description
The precise phase-space distribution and properties of Galactic dark matter necessary for its direct and indirect detection are currently unknown. Since the distributions of normal and dark matter in the Milky Way are coupled to each other as they both move in the same gravitational potential, constraints on the distribution and properties of dark matter can be derived by studying the distribution of visible matter in the Galaxy and making some general assumptions regarding the phase-space distribution of the dark matter. In this study, the visible components of the Galaxy have been comprehensively reviewed to create an axisymmetric model of the Galaxy that is consistent with the available observations, and the dark matter phase-space distribution is assumed to follow a lowered-isothermal form. Poisson's equations are then solved self-consistently to construct models of the spatial and velocity distribution of Galactic dark matter. The total gravitational potential from normal and dark matter are calculated and compared to the current observations of the rotation curve and to the radial velocity distributions of blue horizontal-branch and blue straggler stars. It is found that this analysis allows for a wide range of parameters for the dark matter. The implications for direct and indirect detection of dark matter are discussed in detail. In the appendices, two additional projects are presented. In Appendix A, the recent observations of the positron fraction and the total electron spectrum in cosmic rays are addressed by considering a nested leaky-box model for the propagation of cosmic rays in the Galaxy. This is found to obviate the need for exotic processes such as the annihilation or decay of dark matter to explain the recent observations. In Appendix B, we discuss a novel dark matter detector involving triggered cavitation in acoustic fields. The theory behind the detector is presented in detail, and we discuss the work than has been done to create a prototype at Washington University.
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: Masato Shirasaki
Publisher: Springer
ISBN: 9812877967
Category : Science
Languages : en
Pages : 144
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Book Description
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.
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.
