HAL : in2p3-00414345, version 1
 DOI : 10.1038/nature08278
 Nature 460, 7258 (2009) 990-994
 An upper limit on the stochastic gravitational-wave background of cosmological origin
 VIRGO Collaboration(s)
 (2009)
 A stochastic background of gravitational waves is expected to arise from a superposition of a large number of unresolved gravitational-wave sources of astrophysical and cosmological origin. It should carry unique signatures from the earliest epochs in the evolution of the Universe, inaccessible to standard astrophysical observations. Direct measurements of the amplitude of this background are therefore of fundamental importance for understanding the evolution of the Universe when it was younger than one minute. Here we report limits on the amplitude of the stochastic gravitational-wave background using the data from a two-year science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). Our result constrains the energy density of the stochastic gravitational-wave background normalized by the critical energy density of the Universe, in the frequency band around 100 Hz, to be <6.9 times 10-6 at 95% confidence. The data rule out models of early Universe evolution with relatively large equation-of-state parameter, as well as cosmic (super)string models with relatively small string tension that are favoured in some string theory models. This search for the stochastic background improves on the indirect limits from Big Bang nucleosynthesis and cosmic microwave background at 100 Hz.
 équipe(s) de recherche : APC - Cosmologie et GravitationAPC - ADAMISvirgo
 Thème(s) : Physique/Relativité Générale et Cosmologie Quantique
 in2p3-00414345, version 1 http://hal.in2p3.fr/in2p3-00414345 oai:hal.in2p3.fr:in2p3-00414345 Contributeur : Nicole Berger <> Soumis le : Mardi 8 Septembre 2009, 17:15:42 Dernière modification le : Dimanche 17 Juin 2012, 23:37:58
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