Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Indirect Searches For Dark Matter With The Fermi Large Area Telescope
Download Indirect Searches For Dark Matter With The Fermi Large Area Telescope full books in PDF, epub, and Kindle. Read online Indirect Searches For Dark Matter With The Fermi Large Area Telescope ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Indirect Searches for Dark Matter with the Fermi Large Area Telescope by :
Download or read book Indirect Searches for Dark Matter with the Fermi Large Area Telescope written by and published by . This book was released on 2015 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis The Search for Dark Matter with the Fermi Gamma Ray Space Telescope by :
Download or read book The Search for Dark Matter with the Fermi Gamma Ray Space Telescope written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fermi Gamma-Ray Space Telescope has been scanning the gamma ray sky since it was launched by NASA in June 2008 and has a mission lifetime goal of 10 years. Largely due to our particle physics heritage, one of the main physics topics being studied by the Fermi LAT Collaboration is the search for dark matter via indirect detection. My talk will review the progress of these studies, something on how the LAT detector enables them, and expectations for the future. I will discuss both gamma-ray and (electron + positron) searches for dark matter, and some resulting theoretical implications.
Book Synopsis Optimized Dark Matter Searches in Deep Observations of Segue 1 with MAGIC by : Jelena Aleksić
Download or read book Optimized Dark Matter Searches in Deep Observations of Segue 1 with MAGIC written by Jelena Aleksić and published by Springer. This book was released on 2015-11-06 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the results of indirect dark matter searches in the gamma-ray sky of the near Universe, as seen by the MAGIC Telescopes. The author has proposed and led the 160 hours long observations of the dwarf spheroidal galaxy Segue 1, which is the deepest survey of any such object by any Cherenkov telescope so far. Furthermore, she developed and completely characterized a new method, dubbed “Full Likelihood”, that optimizes the sensitivity of Cherenkov instruments for detection of gamma-ray signals of dark matter origin. Compared to the standard analysis techniques, this novel approach introduces a sensitivity improvement of a factor of two (i.e. it requires 4 times less observation time to achieve the same result). In addition, it allows a straightforward merger of results from different targets and/or detectors. By selecting the optimal observational target and combining its very deep exposure with the Full Likelihood analysis of the acquired data, the author has improved the existing MAGIC bounds to the dark matter properties by more than one order of magnitude. Furthermore, for particles more massive than a few hundred GeV, those are the strongest constraints from dwarf galaxies achieved by any gamma-ray instrument, both ground-based or space-borne alike.
Book Synopsis Searching for Dwarf Spheroidal Galaxies and Other Galactic Dark Matter Substructures with the Fermi Large Area Telescope by :
Download or read book Searching for Dwarf Spheroidal Galaxies and Other Galactic Dark Matter Substructures with the Fermi Large Area Telescope written by and published by . This book was released on 2013 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Dark Matter Searches with the Fermi-LAT in the Direction of Dwarf Spheroidals by :
Download or read book Dark Matter Searches with the Fermi-LAT in the Direction of Dwarf Spheroidals written by and published by . This book was released on 2015 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Search for Gamma-ray Emission from Dark Matter Annihilation in the Large Magellanic Cloud with the Fermi Large Area Telescope by :
Download or read book Search for Gamma-ray Emission from Dark Matter Annihilation in the Large Magellanic Cloud with the Fermi Large Area Telescope written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Particle Dark Matter by : Gianfranco Bertone
Download or read book Particle Dark Matter written by Gianfranco Bertone and published by Cambridge University Press. This book was released on 2010-01-07 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the dark matter problem in particle physics, astrophysics and cosmology for graduate students and researchers.
Book Synopsis Dark Matter Searches With GLAST. by :
Download or read book Dark Matter Searches With GLAST. written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis The Role of Halo Substructure in Gamma-Ray Dark Matter Searches by : Miguel A. Sánchez-Conde
Download or read book The Role of Halo Substructure in Gamma-Ray Dark Matter Searches written by Miguel A. Sánchez-Conde and published by MDPI. This book was released on 2020-05-28 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Dark Matter Searches Targeting Dwarf Spheroidal Galaxies with the Fermi Large Area Telescope by :
Download or read book Dark Matter Searches Targeting Dwarf Spheroidal Galaxies with the Fermi Large Area Telescope written by and published by . This book was released on 2015 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Stringent Constraints on the Dark Matter Annihilation Cross Section From Subhalo Searches with the Fermi Gamma-Ray Space Telescope by :
Download or read book Stringent Constraints on the Dark Matter Annihilation Cross Section From Subhalo Searches with the Fermi Gamma-Ray Space Telescope written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The dark matter halo of the Milky Way is predicted to contain a very large number of smaller subhalos. As a result of the dark matter annihilations taking place within such objects, the most nearby and massive subhalos could appear as point-like or spatially extended gamma-ray sources, without observable counterparts at other wavelengths. In this paper, we use the results of the Aquarius simulation to predict the distribution of nearby subhalos, and compare this to the characteristics of the unidentified gamma-ray sources observed by the Fermi Gamma-Ray Space Telescope. Focusing on the brightest high latitude sources, we use this comparison to derive limits on the dark matter annihilation cross section. For dark matter particles lighter than ~200 GeV, the resulting limits are the strongest obtained to date, being modestly more stringent than those derived from observations of dwarf galaxies or the Galactic Center. We also derive independent limits based on the lack of unidentified gamma-ray sources with discernible spatial extension, but these limits are a factor of ~2-10 weaker than those based on point-like subhalos. Lastly, we note that four of the ten brightest high-latitude sources exhibit a similar spectral shape, consistent with 30-60 GeV dark matter particles annihilating to b quarks with an annihilation cross section on the order of sigma v ~ (5-10) x 10^-27 cm^3/s, or 8-10 GeV dark matter particles annihilating to taus with sigma v ~ (2.0-2.5) x 10^-27 cm^3/s.
Book Synopsis Limits to Dark Matter Annihilation Cross-section from a Combined Analysis of MAGIC and Fermi-LAT Observations of Dwarf Satellite Galaxies by :
Download or read book Limits to Dark Matter Annihilation Cross-section from a Combined Analysis of MAGIC and Fermi-LAT Observations of Dwarf Satellite Galaxies written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the first joint analysis of gamma-ray data from the MAGIC Cherenkov telescopes and the Fermi Large Area Telescope (LAT) to search for gamma-ray signals from dark matter annihilation in dwarf satellite galaxies. We combine 158 hours of Segue 1 observations with MAGIC with 6-year observations of 15 dwarf satellite galaxies by the Fermi-LAT. We obtain limits on the annihilation cross-section for dark matter particle masses between 10 GeV and 100 TeV - the widest mass range ever explored by a single gamma-ray analysis. These limits improve on previously published Fermi-LAT and MAGIC results by up to a factor of two at certain masses. Our new inclusive analysis approach is completely generic and can be used to perform a global, sensitivity-optimized dark matter search by combining data from present and future gamma-ray and neutrino detectors.
Book Synopsis Limits on Dark Matter Annihilation Signals from the Fermi LAT 4-year Measurement of the Isotropic Gamma-Ray Background by :
Download or read book Limits on Dark Matter Annihilation Signals from the Fermi LAT 4-year Measurement of the Isotropic Gamma-Ray Background written by and published by . This book was released on 2015 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: We search for evidence of dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) measured with 50 months of Fermi Large Area Telescope (LAT) observations. An improved theoretical description of the cosmological DM annihilation signal, based on two complementary techniques and assuming generic weakly interacting massive particle (WIMP) properties, renders more precise predictions compared to previous work. More specifically, we estimate the cosmologically-induced gamma-ray intensity to have an uncertainty of a factor ~ 20 in canonical setups. We consistently include both the Galactic and extragalactic signals under the same theoretical framework, and study the impact of the former on the IGRB spectrum derivation. We find no evidence for a DM signal and we set limits on the DM-induced isotropic gamma-ray signal. Our limits are competitive for DM particle masses up to tens of TeV and, indeed, are the strongest limits derived from Fermi LAT data at TeV energies. This is possible thanks to the new Fermi LAT IGRB measurement, which now extends up to an energy of 820 GeV. As a result, we quantify uncertainties in detail and show the potential this type of search offers for testing the WIMP paradigm with a complementary and truly cosmological probe of DM particle signals.
Book Synopsis Dark Matter in the Milky Way by : Laura Jan Chang
Download or read book Dark Matter in the Milky Way written by Laura Jan Chang and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope by :
Download or read book Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope written by and published by . This book was released on 2012 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10−26 cm3 s−1 at 5 GeV to about 5 x 10−23 cm3 s−1 at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section (≈3 x 10−26 cm3 s−1 for a purely s-wave cross section), without assuming additional boost factors.
Book Synopsis Fermi LAT Search for Photon Lines from 30 to 200 GeV. by :
Download or read book Fermi LAT Search for Photon Lines from 30 to 200 GeV. written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter (DM) particle annihilation or decay can produce monochromatic [gamma]-rays readily distinguishable from astrophysical sources. [gamma]-ray line limits from 30 GeV to 200 GeV obtained from 11 months of Fermi Large Area Space Telescope data from 20-300 GeV are presented using a selection based on requirements for a [gamma]-ray line analysis, and integrated over most of the sky. We obtain [gamma]-ray line flux upper limits in the range 0.6-4.5 x 10−9 cm−2s−1, and give corresponding DM annihilation cross-section and decay lifetime limits. Theoretical implications are briefly discussed.
Book Synopsis Observations of MilkyWay Dwarf Spheroidal Galaxies with the Fermi-LAT Detector and by :
Download or read book Observations of MilkyWay Dwarf Spheroidal Galaxies with the Fermi-LAT Detector and written by and published by . This book was released on 2010 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the observations of 14 dwarf spheroidal galaxies with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope, which is conducting an all-sky [gamma]-ray survey in the 20 MeV to>300 GeV energy range, provides a new opportunity to test particle dark matter models through the expected [gamma]-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf spheroidal galaxies, the largest galactic substructures predicted by the cold dark matter scenario, are attractive targets for such indirect searches for dark matter because they are nearby and among the most extreme dark matter dominated environments. No significant [gamma]-ray emission was detected above 100 MeV from the candidate dwarf galaxies. We determine upper limits to the [gamma]-ray flux assuming both power-law spectra and representative spectra from WIMP annihilation. The resulting integral flux above 100 MeV is constrained to be at a level below around 10−9 photons cm−2s−1. Using recent stellar kinematic data, the [gamma]-ray flux limits are combined with improved determinations of the dark matter density profile in 8 of the 14 candidate dwarfs to place limits on the pair annihilation cross-section ofWIMPs in several widely studied extensions of the standard model, including its supersymmetric extension and other models that received recent attention. With the present data, we are able to rule out large parts of the parameter space where the thermal relic density is below the observed cosmological dark matter density and WIMPs (neutralinos here) are dominantly produced non-thermally, e.g. in models where supersymmetry breaking occurs via anomaly mediation. The [gamma]-ray limits presented here also constrain some WIMP models proposed to explain the Fermi and PAMELA ee− data, including low-mass wino-like neutralinos and models with TeV masses pair-annihilating into muon-antimuon pairs.
