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Gravitational waves

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Full-Text Articles in Physics

Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, Ligo Scientific Collaboration, Nelson Christensen, Jan 2008

Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, Ligo Scientific Collaboration, Nelson Christensen,

Faculty Work

We present direct upper limits on gravitational wave emission from the Crab pulsar using data from the first nine months of the fifth science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). These limits are based on two searches. In the first we assume that the gravitational wave emission follows the observed radio timing, giving an upper limit on gravitational wave emission that beats indirect limits inferred from the spin-down and braking index of the pulsar and the energetics of the nebula. In the second we allow for a small mismatch between the gravitational and radio signal frequencies and interpret …


Coherent Bayesian Inference On Compact Binary Inspirals Using A Network Of Interferometric Gravitational Wave Detectors, Christian R¨Over, Renate Meyer, Nelson Christensen Jan 2007

Coherent Bayesian Inference On Compact Binary Inspirals Using A Network Of Interferometric Gravitational Wave Detectors, Christian R¨Over, Renate Meyer, Nelson Christensen

Faculty Work

Presented in this paper is the description of a Markov chain Monte Carlo (MCMC) routine for conducting coherent parameter estimation for interferometric gravitational wave observations of an inspiral of binary compact objects using multiple detectors. Data from several interferometers are processed, and all nine parameters (ignoring spin) associated with the binary system are inferred, including the distance to the source, the masses, and the location on the sky. The data is matched with time-domain inspiral templates that are 2.5 post-Newtonian (PN) in phase and 2.0 PN in amplitude. We designed and tuned an MCMC sampler so that it is able …