Axially symmetric gravitational radiation from isolated sources

1984 ◽  
Vol 25 (12) ◽  
pp. 3527-3537 ◽  
Author(s):  
David W. Hobill
Keyword(s):  
Gravitational Radiation ◽  
Axially Symmetric

CENTER OF MASS AND SPIN FOR AXIALLY SYMMETRIC SPACETIMES

2011 ◽  
Vol 20 (05) ◽  
pp. 717-728 ◽  
Author(s):  
CARLOS KOZAMEH ◽  
RAUL ORTEGA ◽  
TERESITA ROJAS
Keyword(s):  
Angular Momentum ◽  
Gravitational Radiation ◽  
Total Angular Momentum ◽  
Equations Of Motion ◽  
Center Of Mass ◽  
Axially Symmetric ◽  
Symmetric Spacetimes ◽  
Intrinsic Angular Momentum

We give equations of motion for the center of mass and intrinsic angular momentum of axially symmetric sources that emit gravitational radiation. This symmetry is used to uniquely define the notion of total angular momentum. The center of mass then singles out the intrinsic angular momentum of the system.

scholarly journals GRAVITATIONAL WAVES FROM COALESCING BINARY SOURCES

2010 ◽  
Vol 19 (14) ◽  
pp. 2295-2298 ◽  
Author(s):  
M. D. MAIA
Keyword(s):  
Gravitational Waves ◽  
Gravitational Radiation ◽  
Theoretical Basis ◽  
Binary Systems ◽  
Translational Symmetry ◽  
Axially Symmetric ◽  
Poincaré Symmetry ◽  
Group Of Isometries ◽  
Coalescing Binary Systems ◽  
Binary Sources

Coalescing binary systems (e.g. pulsars, neutron stars and black holes) are currently considered to be the most likely sources of gravitational radiation, yet to be detected on or near Earth, where the local gravitational field is negligible and the Poincaré symmetry rules. On the other hand, the general theory of gravitational waves emitted by axially symmetric rotating sources predicts the existence of a nonvanishing news function. The existence of such function implies that, for a distant observer, the asymptotic group of isometries, the BMS group, has a translational symmetry that depends on the orbit periodicity of the source, thus breaking the isotropy of the Poincaré translations. These results suggest that the asymptotic BMS-covariant wave equation should be applied to obtain a proper theoretical basis for the gravitational waves observations from those binary sources.

scholarly journals Axially symmetric dissipative fluids in the quasi-static approximation

2016 ◽  
Vol 25 (03) ◽  
pp. 1650036 ◽  
Author(s):  
L. Herrera ◽  
A. Di Prisco ◽  
J. Ospino ◽  
J. Carot
Keyword(s):  
Gravitational Radiation ◽  
A Priori ◽  
Boundary Surface ◽  
Fluid Distribution ◽  
Axially Symmetric ◽  
Static Approximation ◽  
Quasi Static Approximation ◽  
Static Regime ◽  
Definition Of ◽  
Dissipative Fluids

Using a framework based on the [Formula: see text] formalism, we carry out a study on axially and reflection symmetric dissipative fluids, in the quasi-static regime. We first derive a set of invariantly defined “velocities”, which allow for an inambiguous definition of the quasi-static approximation. Next, we rewrite all the relevant equations in this approximation and extract all the possible, physically relevant, consequences ensuing the adoption of such an approximation. In particular, we show how the vorticity, the shear and the dissipative flux, may lead to situations where different kind of “velocities” change their sign within the fluid distribution with respect to their sign on the boundary surface. It is shown that states of gravitational radiation are not a priori incompatible with the quasi-static regime. However, any such state must last for an infinite period of time, thereby diminishing its physical relevance.

The new formula for gravitational-radiation energy loss and the axially symmetric two-body problem

1986 ◽  
Vol 64 (2) ◽  
pp. 134-139 ◽  
Author(s):  
F. I. Cooperstock ◽  
P. H. Lim
Keyword(s):  
Equation Of State ◽  
Energy Loss ◽  
Gravitational Radiation ◽  
Body Problem ◽  
Radiation Energy ◽  
Axially Symmetric ◽  
Two Body Problem ◽  
Radiation Energy Loss ◽  
Order Of Magnitude ◽  
New Formula

We present the new formula for gravitational-radiation energy loss that replaces the familiar quadrupole formula. The new formula helps to clarify why the quadrupole formula works when it does. The origin of the correction tensor is discussed and then applied to the axially symmetric two-body problem. With the conventional equation of state, ε = ε(P), the correction tensor vanishes and the radiation is that of the bulk-motion quadrupole formula. This is to be compared with our earlier result with an unconventional equation of state giving more radiation and with that of critics claiming dominant radiation via internal motions with the quadrupole formula. An order-of-magnitude calculation is performed for a binary system, where it is found that there is the potential for contributions from nonlinear terms to be as significant as those from the linear terms after(Gm/α)−5/6 orbits. This occurs after ~102 years for the binary pulsar PSR1913 + 16.

Solar Internal Rotation and Dynamo Waves: A Two-Dimensional Asymptotic Solution in the Convection Zone

2000 ◽  
Vol 179 ◽  
pp. 379-380
Author(s):  
Gaetano Belvedere ◽  
Kirill Kuzanyan ◽  
Dmitry Sokoloff
Keyword(s):  
Magnetic Field ◽  
Asymptotic Solution ◽  
Internal Rotation ◽  
Convection Zone ◽  
General Idea ◽  
Dynamo Model ◽  
Axially Symmetric ◽  
Dynamo Action ◽  
Regeneration Rate ◽  
Dynamo Waves

Extended abstractHere we outline how asymptotic models may contribute to the investigation of mean field dynamos applied to the solar convective zone. We calculate here a spatial 2-D structure of the mean magnetic field, adopting real profiles of the solar internal rotation (the Ω-effect) and an extended prescription of the turbulent α-effect. In our model assumptions we do not prescribe any meridional flow that might seriously affect the resulting generated magnetic fields. We do not assume apriori any region or layer as a preferred site for the dynamo action (such as the overshoot zone), but the location of the α- and Ω-effects results in the propagation of dynamo waves deep in the convection zone. We consider an axially symmetric magnetic field dynamo model in a differentially rotating spherical shell. The main assumption, when using asymptotic WKB methods, is that the absolute value of the dynamo number (regeneration rate) |D| is large, i.e., the spatial scale of the solution is small. Following the general idea of an asymptotic solution for dynamo waves (e.g., Kuzanyan & Sokoloff 1995), we search for a solution in the form of a power series with respect to the small parameter |D|–1/3(short wavelength scale). This solution is of the order of magnitude of exp(i|D|1/3S), where S is a scalar function of position.

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