Tuesday, June 18, 2013

1306.3865 (Yan Wang et al.)

Octahedron configuration for a displacement noise-cancelling gravitational wave detector in space    [PDF]

Yan Wang, Stanislav Babak, Antoine Petiteau, David Keitel, Markus Otto, Simon Barke, Fumiko Kawazoe, Alexander Khalaidovski, Vitali Müller, Daniel Schütze, Holger Wittel, Karsten Danzmann, Bernard F. Schutz
We study for the first time a 3-dimensional octahedron constellation for a space-based gravitational wave detector, which we call OGO: the Octahedral Gravitational Observatory. With six spacecraft the constellation is able to remove laser frequency noise and acceleration disturbances from the gravitational wave signal without needing LISA-like drag-free control, thereby simplifying the payloads and placing less stringent demands on the thrusters. We generalize LISA's time-delay interferometry (TDI) to displacement-noise free interferometry (DFI) by deriving a set of generators for those combinations of the data streams which cancel laser and acceleration noise. Orbit dynamical considerations suggest a halo orbit near the Lagrangian point L1, allowing only relatively short arms. For these orbits, we derive the sensitivity curve of this detector concept, which has a peak sensitivity near 100 Hz. We compare this version of OGO to the present generation of ground-based detectors and to some future detectors. Since the sensitivity of OGO is limited mainly by shot noise, we discuss how the overall sensitivity could be improved by using advanced technologies that reduce just this noise source. We also investigate the scientific potentials of such a detector, which include observing gravitational waves from compact binary coalescences, the stochastic background and pulsars as well as the possibility to test alternative theories of gravity. Finding alternative orbits that allow longer arms for the octahedron constellation might further improve its sensitivity and science output.
View original: http://arxiv.org/abs/1306.3865

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