8,621 research outputs found

    The Ulysses Supplement to the BATSE 3B Catalog of Cosmic Gamma-Ray Bursts

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    We present Interplanetary Network localization information for 218 gamma-ray bursts in the 3rd BATSE catalog, obtained by analyzing the arrival times of these bursts at the Ulysses and Compton Gamma-Ray Observatory (CGRO) spacecraft. For any given burst observed by these two spacecraft, arrival time analysis (or "triangulation") results in an annulus of possible arrival directions whose half-width varies between 7 arcseconds and 32 arcminutes, depending on the intensity and time history of the burst, and the distance of the Ulysses spacecraft from Earth. This annulus generally intersects the BATSE error circle, resulting in an average reduction of the error box area of a factor of 30.Comment: Accepted for publication in the Astrophysical Journal Supplemen

    The Interplanetary Network Supplement to the BeppoSAX Gamma-Ray Burst Catalogs

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    Between 1996 July and 2002 April, one or more spacecraft of the interplanetary network detected 787 cosmic gamma-ray bursts that were also detected by the Gamma-Ray Burst Monitor and/or Wide-Field X-Ray Camera experiments aboard the BeppoSAX spacecraft. During this period, the network consisted of up to six spacecraft, and using triangulation, the localizations of 475 bursts were obtained. We present the localization data for these events.Comment: 89 pages, 3 figures. Submitted to the Astrophysical Journal Supplement Serie

    SGR 1806-20 Is a Set of Independent Relaxation Systems

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    The Soft Gamma Repeater 1806-20 produced patterns of bursts during its 1983 outburst that indicate multiple independent energy accumulation sites, each driven by a continuous power source, with sudden, incomplete releases of the accumulated energy. The strengths of the power sources and their durations of activity vary over several orders of magnitude.Comment: Accepted ApJLett, 15 pages, 3 figure

    McScatter: a Simple Three-Body Scattering Package with Stellar Evolution

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    We describe a simple computer package which illustrates a method of combining stellar dynamics with stellar evolution. Though the method is intended for elaborate applications (especially the dynamical evolution of rich star clusters) it is illustrated here in the context of three-body scattering, i.e. interactions between a binary star and a field of single stars. We describe the interface between the dynamics and the two independent packages which describe the internal evolution of single stars and binaries. We also give an example application, and introduce a stand alone utility for the visual presentation of simulation results.Comment: 16 pages, Accepted for publication in New Astronomy. Source codes available at: http://manybody.org/manybody/McScatter.html and http://www.manybody.org/manybody/roche.htm

    Feasibility study of an Integrated Program for Aerospace-vehicle Design (IPAD) system. Volume 1: Summary

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    An overview is provided of the Ipad System, including its goals and objectives, organization, capabilities and future usefulness. The systems implementation is also presented with operational cost summaries

    The Ulysses Supplement to the BATSE 4Br Catalog of Cosmic Gamma-Ray Bursts

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    We present Interplanetary Network localization information for 147 gamma-ray bursts observed by the Burst and Transient Source Experiment between the end of the 3rd BATSE catalog and the end of the 4th BATSE catalog, obtained by analyzing the arrival times of these bursts at the Ulysses and Compton Gamma-Ray Observatory (CGRO) spacecraft. For any given burst observed by these two spacecraft, arrival time analysis (or "triangulation") results in an annulus of possible arrival directions whose half-width varies between 7 arcseconds and 2.3 degrees, depending on the intensity and time history of the burst, and the distance of the Ulysses spacecraft from Earth. This annulus generally intersects the BATSE error circle, resulting in an average reduction of the error box area of a factor of 25.Comment: Accepted for publication in the Astrophysical Journal Supplemen

    Psycho-social effects of a brain-training program among healthy older adults

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    Grounded in cognitive neuroscience and social exchange theory, this research evaluated the relationship between changes in cognitive functioning and two psycho-social dimensions of life among healthy adults over the age of 70 (N=12). Specific psycho-social dimensions examined were social interaction and depression. Six females and six males participated in the study. All were white, college-educated individuals residing in a life-care residential retirement community. The participants used the Posit Science¼ Brain Fitness Programℱ, an auditory-based computer training program that improves memory and speed of processing, for forty hours over an eight-week period. Pre- and post-tests related to social interaction and depressive symptoms indicated that improvement in cognitive functioning was related to improvement in psychosocial dimensions in later life

    Shackleton’s enduring legacy

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    Sir Ernest Shackleton’s name is one forever associated with the Antarctic Heroic Era (1895–1922), the latter year being that of his death. Shackleton was an intrepid explorer, voyaging to Antarctica four times and is often compared to contemporary explorers Roald Amundsen, Douglas Mawson and Robert Falcon Scott. Shackleton’s achievements are a result of a combination of natural leadership and finely-tuned management skills, assisted by a strong element of luck. This paper explores Shackleton’s enduring legacy through the contemporary lens of scientific discovery and exploration, modern leadership training methods and management techniques, and observations of his influence upon Antarctic tourism, particularly “adventure” tourism

    No Evidence for Gamma-Ray Burst/Abell Cluster or Gamma- Ray Burst/Radio-Quiet Quasar Correlations

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    We examine the recent claims that cosmic gamma-ray bursts are associated with either radio-quiet quasars or Abell clusters. These associations were based on positional coincidences between cataloged quasars or Abell clusters, and selected events from the BATSE 3B catalog of gamma-ray bursts. We use a larger sample of gamma-ray bursts with more accurate positions, obtained by the 3rd Interplanetary Network, to re-evaluate these possible associations. We find no evidence for either.Comment: Accepted for publication in the Astrophysical Journa
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