The Search For Milky Way Halo Substructure Wimp Annihilations Using The Glast Lat PDF Download
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| Total Pages | : 4 |
| Release | : 2007 |
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Download The Search for Milky Way Halo Substructure WIMP Annihilations Using the GLAST LAT. Book in PDF, ePub and Kindle
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 | : Miguel A. Sánchez-Conde |
| Publisher | : MDPI |
| Total Pages | : 220 |
| Release | : 2020-05-28 |
| Genre | : Mathematics |
| ISBN | : 3039360442 |
Download The Role of Halo Substructure in Gamma-Ray Dark Matter Searches Book in PDF, ePub and Kindle
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.
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| Total Pages | : 4 |
| Release | : 2011 |
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Download GLAST And Dark Matter Substructure in the Milky Way Book in PDF, ePub and Kindle
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 | : L. Wai |
| Publisher | : |
| Total Pages | : 4 |
| Release | : 2005 |
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Download Searches for WIMP Annihilation with GLAST. Book in PDF, ePub and Kindle
We describe signatures for WIMP annihilation in the gamma ray sky which can be observed by the GLAST mission, scheduled for launch in 2007. We review the search regions, which range from galactic substructure in the Milky Way all the way out to cosmological sources.
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| Total Pages | : 176 |
| Release | : 2013 |
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Download Searching for Dwarf Spheroidal Galaxies and Other Galactic Dark Matter Substructures with the Fermi Large Area Telescope Book in PDF, ePub and Kindle
Over the past century, it has become clear that about a quarter of the known universe is composed of an invisible, massive component termed ''dark matter''. Some of the most popular theories of physics beyond the Standard Model suggest that dark matter may be a new fundamental particle that could self-annihilate to produce [gamma] rays. Nearby over-densities in the dark matter halo of our Milky Way present some of the most promising targets for detecting the annihilation of dark matter. We used the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope to search for [gamma] rays produced by dark matter annihilation in Galactic dark matter substructures. We searched for [gamma]-ray emission coincident with Milky Way dwarf spheroidal satellite galaxies, which trace the most massive Galactic dark matter substructures. We also sought to identify nearby dark matter substructures that lack all astrophysical tracers and would be detectable only through [gamma]-ray emission from dark matter annihilation. We found no conclusive evidence for [gamma]-ray emission from dark matter annihilation, and we set stringent and robust constraints on the dark matter annihilation cross section. While [gamma]-ray searches for dark matter substructure are currently the most sensitive and robust probes of dark matter annihilation, they are just beginning to intersect the theoretically preferred region of dark matter parameter space. Thus, we consider future prospects for increasing the sensitivity of [gamma]-ray searches through improvements to the LAT instrument performance and through upcoming wide- field optical surveys.
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| Total Pages | : 2 |
| Release | : 2007 |
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Download Estimate for GLAST LAT Milky Way Dark Matter WIMP Line Sensitivity Book in PDF, ePub and Kindle
The LAT Dark Matter and New Physics Working group has been developing approaches for the indirect astrophysical detection of annihilation of dark matter. Our work has assumed that a significant component of dark matter is a new type of Weakly Interacting Massive Particle (WIMP). The annihilation of two WIMPs usually results in the production of many high energy gamma rays (>1 GeV) that can be well measured in the GLAST LAT if present. There is also the possibility to observe [gamma] lines from annihilation into [gamma][gamma] and or [gamma]Z final states. In popular SUSY theories these line decays occur at the 10−4 to 10−2 branching fraction level. Estimates of LAT sensitivity (at 5[sigma] above background) and upper limits (upper limit at the 95% confidence level) to these WIMP lines will be presented. These sensitivities are given in photons/cm2/sec/sr and so do not depend on the WIMP models. However, they do depend on the diffuse background model. The latter is derived from GALPROP[1] based on EGRET and other data in the EGRET energy range. We use extrapolations, provided by the GALPROP team to the higher energy range of 150 GeV explored in the preliminary line sensitivity study presented here. Comparison with theory depends upon the WIMP model (e.g., line energy and 1 or 2 lines), the DM halo model, and other astrophysics backgrounds. Thus estimates of the ability of the LAT to actually observe WIMP lines can vary over orders of magnitude depending upon which models are chosen.
| Author | : Michael Kuhlen |
| Publisher | : |
| Total Pages | : 4 |
| Release | : 2009 |
| Genre | : Dark matter (Astronomy) |
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Download Reports Book in PDF, ePub and Kindle
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 | : Aaron J. Sander |
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| Total Pages | : |
| Release | : 2010 |
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Download The Search for Dark Matter in the Milky Way Halo with Fermi Book in PDF, ePub and Kindle
Abstract: This dissertation describes the search for dark matter with the Fermi Gamma-ray Space Telescope. We search for dark matter by looking for the annihilation or decay of dark matter into gamma-rays. We construct models for the astrophysical backgrounds and perform a likelihood analysis to calculate the 95% confidence upper limits on the annihilation cross section vs. mass for the annihilation into b-bbar and tau+ tau- channels. We also calculate the 95% confidence lower limits on the dark matter decay lifetime vs. mass for the mu- mu+ decay channel.
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| Total Pages | : 2 |
| Release | : 2007 |
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Download Analysis Methods for Milky Way Dark Matter Satellite Detection Book in PDF, ePub and Kindle
The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) Dark Matter and New Physics Working group has been developing approaches for the indirect detection of in situ annihilation of dark matter. Our work has assumed that a significant component of dark matter is a new type of Weakly Interacting Massive Particle (WIMP) in the 100GeV mass range. The annihilation of two WIMPs results in the production of a large number of high energy gamma rays (>1GeV) that can be well measured by the GLAST LAT. The cold dark matter model implies a significant number of as yet unobserved dark matter satellites in our galaxy. The spectra of these galactic satellites are considerably harder than most, if not all, astrophysical sources, have an endpoint at the mass of the WIMP, and are not power laws. We describe a preliminary feasibility study for the indirect detection of dark matter satellites in the Milky Way using the GLAST LAT.
| Author | : Geraint F. Lewis |
| Publisher | : World Scientific |
| Total Pages | : 654 |
| Release | : 2008 |
| Genre | : Science |
| ISBN | : 9812814353 |
Download Dark Matter in Astroparticle and Particle Physics Book in PDF, ePub and Kindle
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.
