Download or read book Fermi LAT Observations of the Vela Pulsar written by and published by . This book was released on 2009 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Search for Fermi LAT Pulsars in Archival VERITAS Data written by Jonathan Tyler and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Pulsars are extra-terrestrial sources of periodic radiation thought to consist of highly magnetized, rapidly rotating neutron stars. As the neutron star rotates, beams of radiation may become visible to an observer at different rotational phases, causing an observed periodic signal. Pulsars are mostly detected at radio frequencies, but are also detected in optical light, X-rays and gamma rays. Radiative emission from pulsars is currently not well understood. The main open questions in the field are the radiation emission mechanisms and the location of the emission regions. This work describes the search for pulsations from 14 pulsars with VERITAS, a ground-based very-high-energy (VHE) gamma-ray observatory. Currently only two pulsars have been detected at VHE energies: the Crab and Vela. This search was undertaken in order to increase this number, and to constrain pulsar gamma-ray emission scenarios. The data set consists of archival data, where pulsars detected by the Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope were observed directly or were present in the field of view during observations of other sources. The VERITAS data for each pulsar were analyzed with three sets of data selection cuts, and two periodicity tests for each set of cuts. No pulsations were discovered for any of these analyses. Flux upper limits were calculated for each pulsar at the 95% confidence level for each set of cuts using two separate methods. The limits for each pulsar are contextualized with spectra produced from LAT data, and the results are interpreted within the context of current pulsar gamma-ray emission scenarios. " --
Download or read book Revealing the Most Energetic Light from Pulsars and Their Nebulae written by David Carreto Fidalgo and published by Springer. This book was released on 2019-07-17 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the extraordinary observation of TeV gamma rays from the Crab Pulsar, the most energetic light ever detected from this type of object. It presents detailed information on the painstaking analysis of the unprecedentedly large dataset from the MAGIC telescopes, and comprehensively discusses the implications of pulsed TeV gamma rays for state-of-the-art pulsar emission models. Using these results, the book subsequently explores new testing methodologies for Lorentz Invariance Violation, in terms of a wavelength-dependent speed of light. The book also covers an updated search for Very-High-Energy (VHE), >100 GeV, emissions from millisecond pulsars using the Large Area Telescope on board the Fermi satellite, as well as a study on the promising Pulsar Wind Nebula candidate PSR J0631. The observation of VHE gamma rays is essential to studying the non-thermal sources of radiation in our Universe. Rotating neutron stars, also known as pulsars, are an extreme source class known to emit VHE gamma rays. However, to date only two pulsars have been detected with emissions above 100 GeV, and our understanding of their emission mechanism is still lacking.
Download or read book Blind Searches for Radio quiet Gamma ray Pulsars with Fermi LAT written by Michael Harry Dormody and published by . This book was released on 2011 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Energy Emission from Pulsars and their Systems written by Nanda Rea and published by Springer Science & Business Media. This book was released on 2011-02-04 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of the inaugural meeting of the Sant Cugat Forum on Astrophysics was to address, in a global context, the current understanding of and challenges in high-energy emissions from isolated and non-isolated neutron stars, and to confront the theoretical picture with observations of both the Fermi satellite and the currently operating ground-based Cherenkov telescopes. Participants have also discussed the prospects for possible observations with planned instruments across the multi-wavelength spectrum (e.g. SKA, LOFAR, E-VLT, IXO, CTA) and how they will impact our theoretical understanding of these systems. In keeping with the goals of the Forum, this book not only represents the proceedings of the meeting, but also a reflection on the state-of-the-art in the topic.
Download or read book Pulsar Astronomy written by Andrew Lyne and published by Cambridge University Press. This book was released on 2012-03 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in its fourth edition, Pulsar Astronomy provides a thoroughly revised and updated introduction to the field of pulsar astronomy.
Download or read book Fermi LAT Observations of LS 5039 written by and published by . This book was released on 2012 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. Our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 ± 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300 GeV) of 4.9 ± 0.5(stat) ± 1.8(syst) x 10−7 photon cm−2 s−1, with a cutoff at 2.1 ± 0.3(stat) ± 1.1(syst) GeV and photon index? = 1.9 ± 0.1(stat) ± 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. We suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi.
Download or read book Science With The Cherenkov Telescope Array written by The Cta Consortium and published by World Scientific. This book was released on 2018-12-31 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the science to be carried out by the upcoming Cherenkov Telescope Array, a major ground-based gamma-ray observatory that will be constructed over the next six to eight years. The major scientific themes, as well as core program of key science projects, have been developed by the CTA Consortium, a collaboration of scientists from many institutions worldwide.CTA will be the major facility in high-energy and very high-energy photon astronomy over the next decade and beyond. CTA will have capabilities well beyond past and present observatories. Thus, CTA's science program is expected to be rich and broad and will complement other major multiwavelength and multimessenger facilities. This book is intended to be the primary resource for the science case for CTA and it thus will be of great interest to the broader physics and astronomy communities. The electronic version (e-book) is available in open access.
Download or read book Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula written by and published by . This book was released on 2012 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fermi LAT Search for Pulsar Wind Nebulae Around Gamma Ray Pulsars written by and published by . This book was released on 2012 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OSSE Observations of the Vela Pulsar written by and published by . This book was released on 1993 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The OSSE detector on board the Compton Gamma Ray Observatory observed the Vela Pulsar (PSR 0833-45) during August-September 1991 and April-May 1992. Pulsed emission was detected at the 4-5 sigma level in the 0.06-0.57 MeV band in the sum of the two observing periods, as well as in each individual observation at lower significance. There is no significant variability observed. Light curves have a peak structure similar to that observed at higher energies. The spectrum is hard at lower energies and appears to require a break in the 0.5-2 MeV region.
Download or read book Historical Supernovae and Their Remnants written by Francis Richard Stephenson and published by Oxford University Press on Demand. This book was released on 2002 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text, written by two leading experts, reviews the historical observations of supernova explosions in our Galaxy over the past two thousand years and discusses modern observations of the remnants of these explosions at radio and other wavelengths.
Download or read book Very high energy Gamma ray Observations of Pulsar Wind Nebulae and Cataclysmic Variable Stars with MAGIC and Development of Trigger Systems for IACTs written by Rubén López Coto and published by Springer. This book was released on 2016-09-29 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is a comprehensive work that addresses many of the open questions currently being discusssed in the very-high-energy (VHE) gamma-ray community. It presents a detailed description of the MAGIC telescope together with a glimpse of the future Cherenkov Telescope Array (CTA). One section is devoted to the design, development and characterization of trigger systems for current and future imaging atmospheric Cherenkov telescopes. The book also features a state-of-the-art description of pulsar wind nebula (PWN) systems, the study of the multi-TeV spectrum of the Crab nebula, as well as the discovery of VHE gamma rays at the multiwavelength PWN 3C 58, which were sought at these wavelengths for more than twenty years. It also includes the contextualization of this discovery amongst the current population of VHE gamma-ray PWNe. Cataclysmic variable stars represent a new source of gamma ray energies, and are also addressed here. In closing, the thesis reports on the systematic search for VHE gamma-ray emissions of AE Aquarii in a multiwavelength context and the search for VHE gamma-ray variability of novae during outbursts at different wavelengths.
Download or read book Multiple Messengers and Challenges in Astroparticle Physics written by Roberto Aloisio and published by Springer. This book was released on 2018-02-27 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, designed as a tool for young researchers and graduate students, reviews the main open problems and research lines in various fields of astroparticle physics: cosmic rays, gamma rays, neutrinos, cosmology, and gravitational physics. The opening section discusses cosmic rays of both galactic and extragalactic origin, examining experimental results, theoretical models, and possible future developments. The basics of gamma-ray astronomy are then described, including the detection methods and techniques. Galactic and extragalactic aspects of the field are addressed in the light of recent discoveries with space-borne and ground-based detectors. The review of neutrinos outlines the status of the investigations of neutrino radiation and brings together relevant formulae, estimations, and background information. Three complementary issues in cosmology are examined: observable predictions of inflation in the early universe, effects of dark energy/modified gravity in the large-scale structure of the universe, and neutrinos in cosmology and large-scale structures. The closing section on gravitational physics reviews issues relating to quantum gravity, atomic precision tests, space-based experiments, the strong field regime, gravitational waves, multi-messengers, and alternative theories of gravity.
Download or read book OSSE Observations of the Vela and Geminga Pulsars written by and published by . This book was released on 1996 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Oriented Scintillation Spectrometer Experiment (OSSE) on board the Compton Gamma Ray Observatory detected the Vela Pulsar (PSR B0833-45) during August-September 1991, April-May 1992, and August 1993. Observed light curves have a two-peak pulse profile similar to that observed at higher energies, although the second peak may be wider in the OSSE light curve. Pulsed emission in the first gamma-ray peak was detected with 4.6 sigma statistical significance in the 0.07-0.6 MeV band in the sum of all three observing periods. The second gamma ray peak was detected at no more than 3 sigma significance in the same band. Due to the low statistical significance of the observations, little can be said concerning longer-term temporal variability. The spectrum is hard at lower energies and, in combination with higher energy data, appears to require a break in the 20 MeV region. OSSE also observed Geminga during July 1992, December 1993, and July 1994. No significant pulsed or time averaged emission was observed on any occasion. Upper limits to the pulsed emission suggest, but do not require, a break from the extrapolation of the spectrum measured at higher energies.
Download or read book e ASTROGAM scientific workshop written by Alessandro De Angelis and published by Lulu.com. This book was released on 2017-03-30 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: e-ASTROGAM (enhanced ASTROGAM) is a breakthrough Observatory space mission dedicated to the study of the Universe using gamma-rays in the mostly unexplored and crucial MeV-GeV energy range. e-ASTROGAM has been proposed for the ESA M5 mission. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources. e-ASTROGAM will also determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. e-ASTROGAM has already collected the interest of more that 350 scientists from 19 different countries. About 100 scientists met in Padua from February 28 to March 2, 2017, to discuss some of the more relevant scientific aspects of the mission. This book collects their contributions.
Download or read book Dark Matter in Astrophysics and Particle Physics written by Hans Volker Klapdor-Kleingrothaus and published by World Scientific. This book was released on 2010 with total page 603 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter and dark energy are one of the central mysteries in modern physics, although modern astrophysical and cosmological observations and particle physics experiments can and will provide vital clues in uncovering its true nature. The DARK 2009 Conference brought together World?s leading researchers in both astrophysics and particle physics, providing an opportunity and platform to present their latest results to the community. The topics covered are wide-ranging, from terrestrial underground experiments to space experimental efforts to search for dark matter, and on the theoretical aspects, from the generating of a fifth family as origin of dark matter, extra dimensions and dark matter to non-standard Wigner classes and dark matter. One of the new highlights was certainly a possible connection between a neutrino mass as observed by nuclear double beta decay and the dark energy. Highly important and relevant in its field, the book presents a vital snapshot of the sometimes seemingly disparate areas of dark matter research and offers an exciting overview of current ideas and future directions.
