Scalar gravitational wave from Oppenheimer-Snyder collapse in scalar- tensor theories of gravity

TL;DR

This paper numerically investigates scalar gravitational waves generated by spherically symmetric dust collapse in scalar-tensor theories, revealing how wave features depend on initial conditions and theory parameters, and how observations can inform these parameters.

Contribution

It provides a numerical analysis of scalar gravitational wave generation from dust collapse in scalar-tensor theories, highlighting potential observational signatures for theory parameters.

Findings

Scalar waves depend on initial radius and mass of dust.

Waveform reveals information about the coupling function's derivatives.

Observation can determine initial conditions and theory parameters.

Abstract

Unlike general relativity, scalar-tensor theories of gravity predict scalar gravitational waves even from a spherically symmetric gravitational collapse. We solve numerically the generation and propagation of the scalar gravitational wave from a spherically symmetric and homogeneous dust collapse under the approximation that we can neglect the back reaction of the scalar wave on the space-time, and examine how the amplitude, characteristic frequency and wave form of the observed scalar gravitational wave depend on the initial radius and mass of the dust and parameters contained in the theory. In the Brans-Dicke theory, through the observation of the scalar gravitational wave, it is possible to determine the initial radius and mass and a parameter contained in the theory. In the scalar-tensor theories, it would be possible to get the information of the first derivative of the coupling function contained in the theory because the wave form of the scalar gravitational wave greatly depends on it.