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Open Access research with a European policy impact...

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EPRC is a leading institute in Europe for comparative research on public policy, with a particular focus on regional development policies. Spanning 30 European countries, EPRC research programmes have a strong emphasis on applied research and knowledge exchange, including the provision of policy advice to EU institutions and national and sub-national government authorities throughout Europe.

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Beating the spin-down limit on gravitational wave emission from the Vela pulsar

Abadie, J. and Abbott, B. P. and Abbott, R. and Abernathy, M. and Lockerbie, N. A. and Tokmakov, K. V. and Collaboration, LIGO Sci and Collaboration, Virgo (2011) Beating the spin-down limit on gravitational wave emission from the Vela pulsar. Astrophysical Journal, 737 (2). ISSN 0004-637X

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Abstract

We present direct upper limits on continuous gravitational wave emission from the Vela pulsar using data from the Virgo detector's second science run. These upper limits have been obtained using three independent methods that assume the gravitational wave emission follows the radio timing. Two of the methods produce frequentist upper limits for an assumed known orientation of the star's spin axis and value of the wave polarization angle of, respectively, 1.9 x 10(-24) and 2.2 x 10(-24), with 95% confidence. The third method, under the same hypothesis, produces a Bayesian upper limit of 2.1 x 10(-24), with 95% degree of belief. These limits are below the indirect spin-down limit of 3.3 x 10(-24) for the Vela pulsar, defined by the energy loss rate inferred from observed decrease in Vela's spin frequency, and correspond to a limit on the star ellipticity of similar to 10(-3). Slightly less stringent results, but still well below the spin-down limit, are obtained assuming the star's spin axis inclination and the wave polarization angles are unknown.