Download or read book A Search for 100 TeV Gamma Ray Point Sources written by Timothy Alexander McKay and published by . This book was released on 1992 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Gamma ray Point Sources written by Carl E. Fichtel and published by . This book was released on 1965 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Variability of Point Sources of Gamma Rays Detected by the Fermi Large area Telescope written by Eric Wallace and published by . This book was released on 2016 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Large Area Telescope (LAT) aboard the Fermi Gamma-Ray Space Telescope has revolutionized gamma-ray astronomy, allowing the detection of thousands of point sources of gamma rays. Variability studies are of significant interest as a potential source of information about the emission mechanisms, and as a means to identify gamma-ray sources with known sources in other wavelengths and to improve detection sensitivity in searches for new sources. The inclusion of temporal resolution, however, adds to the already considerable complexity of the required analysis, and as a result, variability studies have generally been limited either in scope or in detail, or both, compared to time-integrated spectral analyses. Pointlike is a software package designed for fast maximum likelihood analysis of LAT data, allowing for interactive and large-scale analyses. Here, we present an application of pointlike to the characterization of the variability of the full sample of known gamma-ray point sources. We describe the construction of light curves in one-month time bins, spanning the first 42 months of the Fermi mission, for a sample of 2652 sources. We discuss the use of the detection significance in individual months to improve the significance of detection of marginal sources, and show that including that measure of significance increases the set of significantly detected sources by nearly 20% compared to using only the average significance. We describe a statistical measure of the significance of variability in a light curve, and examine the variability of the sample as whole, and of subsets associated with particular source types, especially pulsars. We discuss the use of pulsars, which are generally non-variable on long timescales, to calibrate variability statistics, and to assess the importance of systematic errors in estimates of variability. Finally, we discuss the potential to extend the method to produce light curves of longer duration and finer time binning, and to search for transient sources.
Download or read book A Search for Gamma rays from the Crab Nebula Using a Digitized Spark Chamber written by Donald Avery Kniffen and published by . This book was released on 1969 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Extragalactic Gamma ray Point Sources with the HEGAR Air Shower Array written by and published by . This book was released on 1996 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for Gamma Ray Emission from the Region of the Galactic Center written by Glen Hamilton Dahlbacka and published by . This book was released on 1972 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Search for Extragalactic Gamma ray Point Sources with the HEGRA Air Shower Array written by Stefan Westerhoff and published by . This book was released on 1996 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mapping Correlation of Two Point Sources in the Gamma Ray Sky written by and published by . This book was released on 2015 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fermi Gamma-Ray Space Telescope has been taking data on high energy photons or [gamma] rays since June 11th, 2008, and people have been cataloging and profiling point sources of these [gamma] rays ever since. After roughly one year of being in operation over 1400 sources were cataloged. Now, in 2015 we have 3033 sources cataloged. With the increasing amount of sources it's important to think about the limitations of likelihood analysis for highly correlated sources. In this paper I will present the problems of using likelihood analysis for sources that are highly correlated as well as show under what circumstances sources can be considered highly correlated. Dark matter over densities may show up as a point source, so it is a necessary step to learn how the two signals will interact to allow for a proper search for dark matter.
Download or read book Search for Extragalactic ray gamma Ray Point Sources with the HEGRA Air Shower Array written by Stefan Westerhoff and published by . This book was released on 1996 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for Point Sources of Cosmic Gamma Rays at Energies Greater Than 40 TeV written by Gerard H. Gillanders and published by . This book was released on 1989 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gamma ray Large Area Space Telescope written by and published by . This book was released on 1998 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Search for WIMP Dark Matter Continuum Gamma ray Emission from Dark Matter Satellites in the Milky Way Using the Fermi LAT written by Wang Ping and published by Stanford University. This book was released on 2011 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book A Search for Point Sources of Ultrahigh Energy Gamma Rays with the South Pole Air Shower Array written by John Van Stekelenborg and published by . This book was released on 1993 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Very High Energy Cosmic Gamma Radiation written by Felix A. Aharonian and published by World Scientific. This book was released on 2004 with total page 516 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma ray astronomy, the branch of high energy astrophysics that studies the sky in energetic ?-ray photons, is destined to play a crucial role in the exploration of nonthermal phenomena in the Universe in their most extreme and violent forms. The great potential of this discipline offers impressive coverage of many OC hot topicsOCO of modern astrophysics and cosmology, such as the origin of galactic and extragalactic cosmic rays, particle acceleration and radiation processes under extreme astrophysical conditions, and the search for dark matter."
Download or read book A Search for Gamma Radiation Above 24 TeV Energy from Cosmic Point Sources written by Max-Planck-Institut für Physik and published by . This book was released on 1995 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Searching for Dark Matter with Cosmic Gamma Rays written by Andrea Albert and published by Morgan & Claypool Publishers. This book was released on 2016-09-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Ultra High Energy Gamma Ray Point Sources and Cosmic Ray Anisotropy written by Lilian Joan Graham and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
