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A xylophone detector in space

Massimo Tinto (1997)

Banach Center Publications

We discuss spacecraft Doppler tracking for detecting gravitational waves in which Doppler data recorded on the ground are linearly combined with Doppler measurements made on board a spacecraft. By using the four-link radio system first proposed by Vessot and Levine [1] we derive a new method for removing from the combined data the frequency fluctuations due to the Earth troposphere, ionosphere, and mechanical vibrations of the antenna on the ground. This method also reduces the frequency fluctuations...

Einstein-Euler equations for matter spacetimes with Gowdy symmetry

Philippe G. LeFloch (2008/2009)

Séminaire Équations aux dérivées partielles

We investigate the initial value problem for the Einstein-Euler equations of general relativity under the assumption of Gowdy symmetry on T 3 . Given an arbitrary initial data set, we establish the existence of a globally hyperbolic future development and we provide a global foliation of this spacetime in terms of a geometrically defined time-function coinciding with the area of the orbits of the symmetry group. This allows us to construct matter spacetimes with weak regularity which admit, both, impulsive...

Gravitational radiation from accreting neutron stars

Bernard Schutz (1997)

Banach Center Publications

Neutron stars may emit steady gravitational wave signals that will be among the first kinds of gravitational wave signals that the new generation of interferometric detectors will search for. I consider here the possibility that accreting neutron stars may be driven into the steady emission of gravitational waves. I estimate the amplitudes that the waves may have if the accretion takes place at the Eddington limit, such as may happen when a neutron star spirals inside a giant star in the endphase...

Gravitational waveforms from spinning objects

Theocharis Apostolatos (1997)

Banach Center Publications

According to general relativity, a binary consisting of spinning bodies will precess due to spin-orbit and spin-spin coupling. The corresponding modulation of its gravitational waves might be a serious problem for detecting such waves with simple post-Newtonian templates. A new family of templates that takes into account the complications arising from the orbital precession is proposed and its application and performance are discussed.

Gravitational waves from coalescing binaries: a hierarchical signal detection strategy

S. Mohanty, S. Dhurandhar (1997)

Banach Center Publications

The detection of gravitational waves from coalescing compact binaries would be a computationally intensive process if a single bank of template waveforms (i.e., a one step search) is used. We present, in this paper, an alternative method which is a hierarchical search strategy involving two template banks. We show that the computational power required by such a two step search, for an on-line detection of the one parameter family of Newtonian signals, is 1/8 of that required when an on-line one...

Inverse problem for networks of laser interferometers

Piotr Jaranowski (1997)

Banach Center Publications

Estimation of the parameters of the gravitational-wave signal from a coalescing binary by a network of laser interferometers is considered. A generalization of the solution of the inverse problem found previously for the network of 3 detectors to the network of N detectors is given. Maximum likelihood and least squares estimators are applied to obtain the solution. Accuracy of the estimation of the parameters is assessed from the inverse of the Fisher information matrix. The results of the Monte...

New Vacuum Solutions for Quadratic Metric-Affine Gravity - a Metric Affine Model for the Massless Neutrino?

Pasic, Vedad (2010)

Mathematica Balkanica New Series

AMS Subj. Classification: 83C15, 83C35In this paper we present an overview of our research that was presented at theMASSEE International Congress on Mathematics MICOM 2009 in Ohrid, Macedonia. We deal with quadratic metric–affine gravity, which is an alternative theory of gravity. We present new vacuum solutions for this theory and an attempt to give their physical interpretation on the basis of comparison with existing classical models. These new explicit vacuum solutions of quadratic metric–affine...

Post-Newtonian approximation in the test particle limit

Misao Sasaki (1997)

Banach Center Publications

Gravitational radiation from a small mass particle orbiting a massive black hole can be analytically studied to a very high order in the post-Newtonian expansion. Thus it gives us useful information on the evolution of a coalescing compact binary star. In this talk, I report on recent progress made in the black-hole perturbation approach.

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