We present a fully relativistic computation of the torques due to Lindblad resonances from perturbers on circular, equatorial orbits on discs around Schwarzschild and Kerr black holes. The computation proceeds by establishing a relation between the Lindblad torques and the gravitational waveforms emitted by the perturber and a test particle in a slightly eccentric orbit at the radius of the Lin...

We consider the formation of double white dwarfs (DWDs) through dynamical interactions in globular clusters. Such interactions can give rise to eccentric DWDs, in contrast to the exclusively circular population expected to form in the Galactic disk. We show that for a 5 yr Laser Interferometer Space Antenna (LISA) mission and distances as far as the Large Magellanic Cloud, multiple harmonics fr...

The circular grating is used as the measurement standard component in the robot joint-angle test system, however the measurement error is inevitable due to the installation eccentricity. In order to correct the measurement error, both the compensation model and eccentric detection test are needed to be investigated. Firstly, the compensation model about angular error is deduced according to the...

Vacuum perturbations of the Kerr metric can be reconstructed from the corresponding perturbation in either of the two Weyl scalars ψ0 or ψ4, using a procedure described by Chrzanowski and others in the 1970s. More recent work, motivated within the context of self-force physics, extends the procedure to metric perturbations sourced by a particle in a bound geodesic orbit. However, the existing p...

Observations of the Galactic Centre show evidence of disc-like structures of very young stars orbiting the central super-massive black hole within a distance of a few 0.1 pc. While it is widely accepted that about half of the stars form a relatively flat disc rotating clockwise on the sky, there is a substantial ongoing debate on whether there is a second, counter-clockwise disc of stars. By me...

If the stellar population of the bulge contains black holes formed in the final core collapse of ordinary stars with M ∼> 30M⊙, then about 25,000 stellar mass black holes should have migrated by dynamical friction into the central parsec of the Milky Way, forming a black hole cluster around the central supermassive black hole. These black holes can be captured by the central black hole when the...

In this study, the analysis of transverse vibrations of rectangular plate with circular central hole with different boundary conditions is studied and the natural frequencies and natural modes of a rectangular plate with circular hole have been obtained. To solve the problem, it is necessary to use both Cartesian and polar coordinate system. The complexity of the method is to apply an appropria...

Stress concentration factors have been examined in a functionally graded material (FGM) plate with central holes in different shapes in this essay. The material properties change along the thickness of plate. ABAQUS software has been utilized for modeling of problem in which subroutine of ABAQUS sub-program was used for modeling of the targeted material. The considering shapes for hole in plate...

ABSTRACT In this paper, I develop a non-linear theory of tightly wound (highly twisted) eccentric waves in astrophysical discs, based on the averaged Lagrangian method Whitham. Viscous dissipation is included by use pseudo-Lagrangian. This work an extension developed Lee & Goodman to 3D with addition viscosity. confirm that linear are overstable and excited presence shear viscosity show per...