3,823 research outputs found
Eccentricities of Double Neutron Star Binaries
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
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
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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