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Author: Publisher: ISBN: Category : Languages : en Pages : 4
Book Description
We discuss the possibility of GLAST detecting gamma-rays from the annihilation of neutralino dark matter in the Galactic halo. We have used 'Via Lactea', currently the highest resolution simulation of cold dark matter substructure, to quantify the contribution of subhalos to the annihilation signal. We present a simulated allsky map of the expected gamma-ray counts from dark matter annihilation, assuming standard values of particle mass and cross section. In this case GLAST should be able to detect the Galactic center and several individual subhalos. One of the most exciting discoveries that the Gamma-ray Large Area Space Telescope (GLAST) could make, is the detection of gamma-rays from the annihilation of dark matter (DM). Such a measurement would directly address one of the major physics problems of our time: the nature of the DM particle. Whether or not GLAST will actually detect a DM annihilation signal depends on both unknown particle physics and unknown astrophysics theory. Particle physics uncertainties include the type of particle (axion, neutralino, Kaluza-Klein particle, etc.), its mass, and its interaction cross section. From the astrophysical side it appears that DM is not smoothly distributed throughout the Galaxy halo, but instead exhibits abundant clumpy substructure, in the form of thousands of so-called subhalos. The observability of DM annihilation radiation originating in Galactic DM subhalos depends on their abundance, distribution, and internal properties. Numerical simulations have been used in the past to estimate the annihilation flux from DM substructure, but since the subhalo properties, especially their central density profile, which determines their annihilation luminosity, are very sensitive to numerical resolution, it makes sense to re-examine their contribution with higher resolution simulations.
Author: Publisher: ISBN: Category : Languages : en Pages : 4
Book Description
We discuss the possibility of GLAST detecting gamma-rays from the annihilation of neutralino dark matter in the Galactic halo. We have used 'Via Lactea', currently the highest resolution simulation of cold dark matter substructure, to quantify the contribution of subhalos to the annihilation signal. We present a simulated allsky map of the expected gamma-ray counts from dark matter annihilation, assuming standard values of particle mass and cross section. In this case GLAST should be able to detect the Galactic center and several individual subhalos. One of the most exciting discoveries that the Gamma-ray Large Area Space Telescope (GLAST) could make, is the detection of gamma-rays from the annihilation of dark matter (DM). Such a measurement would directly address one of the major physics problems of our time: the nature of the DM particle. Whether or not GLAST will actually detect a DM annihilation signal depends on both unknown particle physics and unknown astrophysics theory. Particle physics uncertainties include the type of particle (axion, neutralino, Kaluza-Klein particle, etc.), its mass, and its interaction cross section. From the astrophysical side it appears that DM is not smoothly distributed throughout the Galaxy halo, but instead exhibits abundant clumpy substructure, in the form of thousands of so-called subhalos. The observability of DM annihilation radiation originating in Galactic DM subhalos depends on their abundance, distribution, and internal properties. Numerical simulations have been used in the past to estimate the annihilation flux from DM substructure, but since the subhalo properties, especially their central density profile, which determines their annihilation luminosity, are very sensitive to numerical resolution, it makes sense to re-examine their contribution with higher resolution simulations.
Author: Publisher: ISBN: Category : Languages : en Pages : 4
Book Description
The GLAST LAT Collaboration is one among several experimental groups, covering a wide range of approaches, pursuing the search for the nature of dark matter. The GLAST LAT has the unique ability to find new sources of high energy gamma radiation emanating directly from WIMP annihilations in situ in the universe. Using it's wide band spectral and full sky spatial capabilities, the GLAST LAT can form ''images'' in high energy gamma-rays of dark matter substructures in the gamma-ray sky. We describe a preliminary feasibility study for indirect detection of milky way dark matter satellites using the GLAST LAT.
Author: Michael Kuhlen Publisher: ISBN: Category : Dark matter (Astronomy) Languages : en Pages : 4
Book Description
The unambiguous detection of dark matter annihilation in our Galaxy would unravel one of the most outstanding puzzles in particle physics and cosmology. Recent observations have motivated models in which the annihilation rate is boosted by the Sommerfeld effect, a nonperturbative enhancement arising from a long-range attractive force. We applied the Sommerfeld correction to Via Lactea II, a high-resolution N-body simulation of a Milky Way-sized galaxy, to investigate the phase-space structure of the galactic halo. We found that the annihilation luminosity from kinematically cold substructure could be enhanced by orders of magnitude relative to previous calculations, leading to the prediction of gamma-ray fluxes from as many as several hundred dark clumps that should be detectable by the Fermi satellite.
Author: Laura Jan Chang Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
We have entered a data-driven era of astrophysics and cosmology, providing a wealth of datasets within which to search for the answers to some of the most fundamental open questions in the physics of our Universe. One of these questions is the nature of dark matter (DM)?while there is phenomenal agreement between the theories of DM and the data on cosmological scales, there remains much to be understood about DM on scales at and smaller than the size of galaxies. This thesis explores the astrophysical and particle physics properties of dark matter in the Milky Way Galaxy. Chapters 2?4 center around indirect detection of DM, the field of research that seeks to detect the Standard Model particles which result from DM annihilation (or decay). The focus here is specifically on searching for signatures of DM annihilation in gamma-ray data from the Fermi Large Area Telescope. Chapters 5?6 are dedicated to understanding substructure in the Milky Way. Chapter 5 focuses on characterizing how well the standard Jeans dynamical mass modeling method performs at accurately capturing the DM content of dwarf galaxies, while Chapter 6 presents a novel machine learning-based approach to inferring the missing information from Gaia stellar data, which can then be used to search for evidence of stellar and DM substructure in the Milky Way.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Indirect detection of particle dark matter relies upon pair annihilation of Weakly Interaction Massive Particles (WIMPs), which is complementary to the well known techniques of direct detection (WIMP-nucleus scattering) and collider production (WIMP pair production). Pair annihilation of WIMPs results in the production of gamma-rays, neutrinos, and anti-matter. Of the various experiments sensitive to indirect detection of dark matter, the Gamma-ray Large Area Space Telescope (GLAST) may play the most crucial role in the next few years. After launch in late 2007, The GLAST Large Area Telescope (LAT) will survey the gamma-ray sky in the energy range of 20MeV-300GeV. By eliminating charged particle background above 100 MeV, GLAST may be sensitive to as yet to be observed Milky Way dark matter subhalos, as well as WIMP pair annihilation spectral lines from the Milky Way halo. Discovery of gamma-ray signals from dark matter in the Milky Way would not only demonstrate the particle nature of dark matter; it would also open a new observational window on galactic dark matter substructure. Location of new dark matter sources by GLAST would dramatically alter the experimental landscape; ground based gamma ray telescopes could follow up on the new GLAST sources with precision measurements of the WIMP pair annihilation spectrum.
Author: Miguel A. Sánchez-Conde Publisher: MDPI ISBN: 3039360442 Category : Mathematics Languages : en Pages : 220
Book Description
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: Geraint F. Lewis Publisher: World Scientific ISBN: 9812814353 Category : Science Languages : en Pages : 654
Book Description
Dark matter remains one of the central mysteries in modern physics, although modern astronomical observations and particle physics experiments are providing vital clues in uncovering its true nature. The Dark2007 Conference brought together world-leading researchers in both astrophysics and particle physics, providing them with an opportunity to present their latest results and engage in discussion on their meaning and future direction. This book is important in its field, as it provides a vital snapshot of the seemingly disparate areas of dark matter research and provides an overview of current ideas and future directions.
Author: Società italiana di fisica Publisher: IOS Press ISBN: 1614992177 Category : Science Languages : en Pages : 739
Book Description
Physics and astrophysics came to dark matter through many different routes, finally accepting it, but often with some distaste. It has been noticed that the existence of dark matter is yet another displacement of humans from the centre of the Universe: not only do our planet and our sun have no central position in the Universe, not only are humans just animals (although with a 'specialized' central nervous system), but even the material of which we are made is only a marginal component of the cosmic substance! If this is the right attitude to take, scientists feeling distaste for dark matter are much like Galileo Galilei's colleagues who refused to look through the telescope to watch the Medici planets. Nevertheless, astronomers, when required to take a ballot in favour of some cosmological model, often still vote for 'pure baryonic' with substantial majorities, although most cosmologists assume that a 'cold' component of dark matter plays a role in producing the world as we observe it. Among the many subjects covered by the book, particular emphasis was given to 1) summarizing the current status of the observations both of the distribution of the nearby galaxies and of the evolution of more distant galaxies; 2) advanced statistical techniques for quantifying structure in galaxy redshift and peculiar velocity surveys; 3) the art of cosmic inflation and models for dark matter candidates, and their implications for cosmic microwave background observations; 4) implications of cold dark matter variants for large scale structure, as worked out both by quasi-linear techniques and by fully nonlinear simulations; and 5) Eulerian and Lagrangian approximations for treating the nonlinear dynamics.
Author: Steven Ritz Publisher: American Institute of Physics ISBN: Category : Science Languages : en Pages : 640
Book Description
The GLAST Symposia provide a forum for the exchange of information across a broad range of scientific investigations. GLAST, NASA's new gamma-ray observatory, opens a new window into the universe. GLAST data will enable scientists to answer questions that arise within a broad range of topics, including super massive black hole systems, pulsars, gamma-ray bursts, the origin of cosmic rays, and searches for signals of new physics.
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Author: Michael Kuhlen
Author: Laura Jan Chang
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Author: Miguel A. Sánchez-Conde
Author: Françoise Combes
Author: Geraint F. Lewis
Author: Società italiana di fisica
Author: Steven Ritz