arXiv subjects

Dan B. Sibandze

Publications and source records attributed to Dan B. Sibandze.

2 recordsLinked to original sources

arXiv2017

Echoes from the black holes: Evidence of higher order corrections to General Relativity in strong gravity regime

We show that the higher order curvature corrections to general relativity in the strong gravity regime of near horizon scales produce a rapidly oscillating and infalling Ricci scalar fireball just outside the horizon. This can generate the ringdown modes of gravitational waves having the same natural frequency as those which are generated by the black hole mergers. Our analysis provides a viable explanation to the echoes in the ringdown modes recently detected from the LIGO data, without invoking the existence of any exotic structures at the horizon.

gr-qc↗

arXiv2016

Scalar wave scattering from Schwarzschild black holes in modified gravity

We consider the scattering of gravitational waves off a Schwarzschild black hole in $f(R)$ gravity. We show that the reflection and transmission coefficients for tensor waves are the same as in General Relativity. While the scalar waves, which are not present in General Relativity, demonstrate interesting features. The equation that governs these scalar waves can be reduced to a Volterra integral equation. Analysis of this equation shows that a larger fraction of these waves are reflected compared to what one obtains for tensors. This may provide a novel observational signature for fourth order gravity.

gr-qc↗