3,823 research outputs found

    Eccentricities of Double Neutron Star Binaries

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    Recent pulsar surveys have increased the number of observed double neutron stars (DNS) in our galaxy enough so that observable trends in their properties are starting to emerge. In particular, it has been noted that the majority of DNS have eccentricities less than 0.3, which are surprisingly low for binaries that survive a supernova explosion that we believe imparts a significant kick to the neutron star. To investigate this trend, we generate many different theoretical distributions of DNS eccentricities using Monte Carlo population synthesis methods. We determine which eccentricity distributions are most consistent with the observed sample of DNS binaries. In agreement with Chaurasia & Bailes (2005), assuming all double neutron stars are equally as probable to be discovered as binary pulsars, we find that highly eccentric, coalescing DNS are less likely to be observed because of their accelerated orbital evolution due to gravitational wave emission and possible early mergers. Based on our results for coalescing DNS, we also find that models with vanishingly or moderately small kicks (sigma < about 50 km/s) are inconsistent with the current observed sample of such DNS. We discuss the implications of our conclusions for DNS merger rate estimates of interest to ground-based gravitational-wave interferometers. We find that, although orbital evolution due to gravitational radiation affects the eccentricity distribution of the observed sample, the associated upwards correction factor to merger rate estimates is rather small (typically 10-40%).Comment: 9 pages, 8 figures, accepted by ApJ. Figures reduced and some content changed, references adde

    Internet Governance : exploring the development link

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    This paper seeks to explore the issues of Internet governance from a development perspective. The WSIS process and the report of the UN Working group on Internet Governance provide an initial framework within which to develop the issues. These issues not only concern the equitable distribution of Internet resources and the ways in which a secure and reliable function of the Internet can be achieved, but also include issues of multi-lingualism and local content as well as the institutional setting of Internet governance mechanisms and participation. The paper observers that realising the contribution of the Internet to development goals requires a shift in policy focus away from supply side initiatives in the telecommunications sector to more co-ordinated approaches

    Internet Governance: exploring the development link

    Get PDF
    This paper seeks to explore the issues of Internet governance from a development perspective. The WSIS process and the report of the UN Working group on Internet Governance provide an initial framework within which to develop the issues. These issues not only concern the equitable distribution of Internet resources and the ways in which a secure and reliable function of the Internet can be achieved, but also include issues of multi-lingualism and local content as well as the institutional setting of Internet governance mechanisms and participation. The paper observers that realising the contribution of the Internet to development goals requires a shift in policy focus away from supply side initiatives in the telecommunications sector to more co-ordinated approaches.Internet governance; development; Internet resources; access
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