Theocharis A. Apostolatos

How to observe a non-Kerr spacetime (2009)

Apostolatos, Theocharis A., Lukes-Gerakopoulos, Georgios, Contopoulos, George

We present a generic criterion which can be used in gravitational-wave data analysis to distinguish an extreme-mass-ratio inspiral into a Kerr background spacetime from one into a non-Kerr background...

Relativistic reactions visualized through right triangles in space (2009)

Apostolatos, Theocharis A.

In this article we exploit the fact that the special relativistic formula which relates the energy and the 3-momentum of an elementary particle with its rest mass, resembles the pythagorean theorem...

Minimizing the kinematical effects on LISA's performance (2008)

Deligiannis, Ioannis, Apostolatos, Theocharis A.

Proper tuning of the orbital characteristics of the three spacecrafts that constitute the usual triangular configuration of the space-borne gravitational-wave detector LISA, could minimize the...

Multipole moments as a tool to infer from gravitational waves the geometry around an axisymmetric body (2006)

Sotiriou, Thomas P., Apostolatos, Theocharis A.

A binary system, composed of a compact object orbiting around a massive central body, will emit gravitational waves which will depend on the central body's spacetime geometry. We expect that the...

The inverse problem for pulsating neutron stars: a `fingerprint analysis' for the supranuclear equation of state (2006)

Kokkotas, Kostas D., Andersson, Nils, Apostolatos, Theocharis A.

We study the problem of detecting, and inferring astrophysical information from, gravitational waves from a pulsating neutron star. We show that the fluid f and p modes, as well as the...

Non-linear pulsations in differentially rotating neutron stars: mass-shedding-induced damping and splitting of the fundamental mode (2006)

Stergioulas, Nickolaos Athanassion, Apostolatos, Theocharis A., Font, Jose A.

We study small-amplitude, non-linear pulsations of uniformly and differentially rotating neutron stars employing a two-dimensional evolution code for general-relativistic hydrodynamics. Using Fourier...

Measuring mass moments and electromagnetic moments of a massive, axisymmetric body, through gravitational waves (2006)

Apostolatos, Theocharis A., Sotiriou, Thomas P.

The electrovacuum around a rotating massive body with electric charge density is described by its multipole moments (mass moments, mass-current moments, electric moments, and magnetic moments). A...

Non-linear pulsations in differentially rotating neutron stars: mass-shedding-induced damping and splitting of the fundamental mode (2006)

Stergioulas, Nickolaos Athanassion, Apostolatos, Theocharis A., Font, Jose A.

We study small-amplitude, non-linear pulsations of uniformly and differentially rotating neutron stars employing a two-dimensional evolution code for general-relativistic hydrodynamics. Using Fourier...

Corrections and Comments on the Multipole Moments of Axisymmetric Electrovacuum Spacetimes (2004)

Sotiriou, Thomas P., Apostolatos, Theocharis A.

Following the method of Hoenselaers and Perj\'{e}s we present a new corrected and dimensionally consistent set of multipole gravitational and electromagnetic moments for stationary axisymmetric...

Nonlinear Pulsations in Differentially Rotating Neutron Stars: Mass-Shedding-Induced Damping and Splitting of the Fundamental Mode (2003)

Stergioulas, Nikolaos, Apostolatos, Theocharis A., Font, Jose A.

We study small-amplitude, nonlinear pulsations of uniformly and differentially rotating neutron stars employing a two-dimensional evolution code for general-relativistic hydrodynamics. Using Fourier...

Spin-induced orbital precession and its modulation of the gravitational waveforms from merging binaries (1994)

Apostolatos, Theocharis A., Cutler, Curt, Sussman, Gerald J., Thorne, Kip S.

Merging compact binaries are currently regarded as the most promising source of gravitational waves for the planned Earth-based LIGO/VIRGO laser-interferometer detector system, and will be an...

The last three minutes: Issues in gravitational-wave measurements of coalescing compact binaries (1993)

Cutler, Curt, Apostolatos, Theocharis A., Bildsten, Lars, Finn, Lee Samuel, Flanagan, Eanna E., Kennefick, Daniel, ...

Gravitational-wave interferometers are expected to monitor the last three minutes of inspiral and final coalescence of neutron star and black hole binaries at distances approaching cosmological,...

Rotation halts cylindrical, relativistic gravitational collapse (1992)

Apostolatos, Theocharis A., Thorne, Kip S.

It is shown, in a simple analytic example, that an infinitesimal amount of rotation can halt the general relativistic gravitational collapse of a pressure-free cylindrical body. The example is a thin...

The Last Three Minutes: Issues in Gravitational Wave Measurements of Coalescing Compact Binaries (1992)

Cutler, Curt, Apostolatos, Theocharis A., Bildsten, Lars, Finn, Lee Samuel, Flanagan, Eanna E., Kennefick, Daniel, ...

Gravitational-wave interferometers are expected to monitor the last three minutes of inspiral and final coalescence of neutron star and black hole binaries at distances approaching cosmological,...