The Search For Dark Matter In The Milky Way Halo With Fermi PDF Download
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| Author | : Aaron J. Sander |
| Publisher | : |
| 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.
| Author | : Gerrit Spengler |
| Publisher | : |
| Total Pages | : 253 |
| Release | : 2014 |
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Download Search for Dark Matter in the Milky Way Halo with the High Energy Stereoscopic System Book in PDF, ePub and Kindle
| Author | : Wang Ping |
| Publisher | : Stanford University |
| Total Pages | : 167 |
| Release | : 2011 |
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Download The Search for WIMP Dark Matter Continuum Gamma-ray Emission from Dark Matter Satellites in the Milky Way Using the Fermi LAT Book in PDF, ePub and Kindle
This thesis focuses on the search for unknown dark matter (DM) satellites in the Milky Way using the Fermi Large Area Space Telescope (LAT). The Fermi Gamma-ray Space Telescope (Fermi) is a next generation space observatory, which was successfully launched on June 11th, 2008. The LAT is the principal scientific instrument onboard. Its unprecedented angular resolution and sensitivity in the 100 MeV to > 300 GeV energy range makes it an excellent instrument for probing the sky for DM satellites. Current N-body simulations based on the Lambda-CDM cosmology model predict a large number of as yet unobserved DM satellites in our galaxy; some satellites are predicted to be extended sources (> 1deg extension) as seen by the LAT. Our work assumes that a significant component of DM is a Weakly Interacting Massive Particle (WIMP) in the 100 GeV mass range. The annihilation of WIMPs results in many high energy gamma rays that can be well measured by the LAT. The WIMP produced gamma-ray spectrum from the putative DM satellites is considerably harder than most astrophysical sources. Also, DM satellites have no astronomical counterparts in the X-ray and radio bands, and the emission has no time variability. My thesis will focus on a blind analysis in the search for unknown DM satellites using one year of LAT data, and setting constraints on some WIMP models based on the results of our analysis in which we find no candidates.
| 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.
| Author | : David Cline |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 140 |
| Release | : 2013-11-25 |
| Genre | : Science |
| ISBN | : 9400772416 |
Download Sources and Detection of Dark Matter and Dark Energy in the Universe Book in PDF, ePub and Kindle
These proceedings provide the latest results on dark matter and dark energy research. The UCLA Department of Physics and Astronomy hosted its tenth Dark Matter and Dark Energy conference in Marina del Rey and brought together all the leaders in the field. The symposium provided a scientific forum for the latest discussions in the field. Topics covered at the symposium: •Status of measurements of the equation of state of dark energy and new experiments •The search for missing energy events at the LHC and implications for dark matter search •Theoretical calculations on all forms of dark matter (SUSY, axions, sterile neutrinos, etc.) •Status of the indirect search for dark matter •Status of the direct search for dark matter in detectors around the world •The low-mass wimp search region •The next generation of very large dark matter detectors •New underground laboratories for dark matter search
| Author | : Govert Schilling |
| Publisher | : Harvard University Press |
| Total Pages | : 377 |
| Release | : 2022-05-31 |
| Genre | : Science |
| ISBN | : 0674276175 |
Download The Elephant in the Universe Book in PDF, ePub and Kindle
A Seminary Co-op Notable Book A BBC Sky at Night Best Book “An impressively comprehensive bird’s-eye view of a research topic that is both many decades established and yet still at the very cutting edge of astronomy and physics.” —Katie Mack, Wall Street Journal “Schilling has craftily combined his lucid and accessible descriptions of science with the personal story of those unlocking the finer details of the missing mass mystery. The result is enthralling...A captivating scientific thriller.” —BBC Sky at Night “Fascinating...A thorough and sometimes troubling account of the hunt for dark matter...You will come away with a very good understanding of how the universe works. Well, our universe, anyway.” —Michael Brooks, New Scientist When you train a telescope on outer space, you can see luminous galaxies, nebulae, stars, and planets. But if you add all that together, it constitutes only 15 percent of the matter in the universe. Despite decades of research, the nature of the remaining 85 percent is unknown. We call it dark matter. Physicists have devised huge, sensitive instruments to search for dark matter, which may be unlike anything else in the cosmos—some unknown elementary particle. Yet so far dark matter has escaped every experiment. It is so elusive that some scientists are beginning to suspect there might be something wrong with our theories about gravity or with the current paradigms of cosmology. Govert Schilling interviews believers and heretics and paints a colorful picture of the history and current status of dark matter research. The Elephant in the Universe is a vivid tale of scientists puzzling their way toward the true nature of the universe.
| Author | : |
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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.
| Author | : |
| Publisher | : |
| Total Pages | : 7 |
| Release | : 2015 |
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Download Indirect Searches for Dark Matter with the Fermi Large Area Telescope Book in PDF, ePub and Kindle
There is overwhelming evidence that non-baryonic dark matter constitutes ~ 27% of the energy density of the Universe. Weakly Interacting Massive Particles (WIMPs) are promising dark matter candidates that may produce [gamma] rays via annihilation or decay detectable by the Fermi Large Area Telescope (LAT). A detection of WIMPs would also indicate the existence of physics beyond the Standard Model. We present recent results from the two cleanest indirect WIMP searches by the Fermi-LAT Collaboration: searches for [gamma]-ray spectral lines and [gamma]-ray emission associated with Milky Way dwarf spheroidal satellite galaxies.
| Author | : Andrea Marie Albert |
| Publisher | : |
| Total Pages | : |
| Release | : 2013 |
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Download Search for Gamma-ray Spectral Lines with the Fermi Large Area Telescope and Dark Matter Implications Book in PDF, ePub and Kindle
Abstract: Measurements indicate that ~85% of the matter in the universe neither emits nor reflects light--appropriately called "dark matter". We believe dark matter may be primary composed of new particles, but we know very little about their nature. What dark matter is and how it interacts is one of the top cosmological mysteries today. Detecting a signal from particle dark matter would not only offer insight into the fundamental nature of dark matter, but it would also be strong evidence for physics existing beyond the Standard Model. A promising dark matter candidate is a weakly interacting massive particle (WIMP). Measurements indicate that the Milky Way Galaxy resides in a halo of dark matter, making it an ideal laboratory for investigating these elusive particles. As WIMPs are predicted to be heavy, their interactions should produce high-energy gamma rays that would be detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope (Fermi). If WIMPs annihilate directly into gamma rays, the gamma-ray energy would be the same as the rest mass energy of the WIMPs, which is currently unknown. This process would cause a "pile-up" of gamma rays at a specific energy, producing a sharp line (or bump) in the otherwise relatively smooth gamma-ray energy spectrum. This distinctive signal would not only be strong evidence for the existence of WIMPs, but would also provide information about their mass. We have searched for spectral lines in the energy range 5 to 300 GeV using 3.7 years of Fermi LAT data, reprocessed with updated calorimeter calibration constants, and an improved energy dispersion model from previous LAT Collaboration line searches. We search in five regions selected to optimize sensitivity to different theoretically-motivated density distributions of WIMPs. We do not find any globally significant lines in our a priori search regions and present 95% confidence limits for annihilation cross section and decay lifetimes. We extensively discuss potential systematic effects in the search. Finally, we consider claims of evidence for a spectral line at 130 GeV, compare our results to previous work, and discuss why this search finds a somewhat lower statistical significance for a potential line than other works.
| Author | : Andrea Albert |
| Publisher | : Morgan & Claypool Publishers |
| Total Pages | : 82 |
| Release | : 2016-09-06 |
| Genre | : Science |
| ISBN | : 1681742705 |
Download Searching for Dark Matter with Cosmic Gamma Rays Book in PDF, ePub and Kindle
Searching for Dark Matter with Cosmic Gamma Rays summarizes the evidence for dark matter and what we can learn about its particle nature using cosmic gamma rays. It has almost been 100 years since Fritz Zwicky first detected hints that most of the matter in the Universe that doesn't directly emit or reflect light. Since then, the observational evidence for dark matter has continued to grow. Dark matter may be a new kind of particle that is governed by physics beyond our Standard Model of particle physics. In many models, dark matter annihilation or decay produces gamma rays. There are a variety of instruments observing the gamma-ray sky from tens of MeV to hundreds of TeV. Some make deep, focused observations of small regions, while others provide coverage of the entire sky. Each experiment offers complementary sensitivity to dark matter searches in a variety of target sizes, locations, and dark matter mass scales. We review results from recent gamma-ray experiments including anomalies some have attributed to dark matter. We also discuss how our gamma-ray observations complement other dark matter searches and the prospects for future experiments.
