Overtones, mirror modes, and mode-mixing in binary black hole mergers

Abstract

Gravitational waves emitted in the aftermath of a black hole binary coalescence have characteristic complex frequencies called quasinormal modes (QNMs). These can be used to test the nature of the merger remnant, e.g. a test of the black hole "no-hair" theorem. The relative excitation amplitudes of the QNMs contain information about the progenitor system and can be employed to test the consistency between the pre- and post-merger signals. The post-merger signal from numerical relativity (NR) simulations of binary black holes exhibit a rich structure that has to be understood to fully exploit the information contained therein. In this study, we examine the importance of \emph{overtones} and \emph{mirror} modes for a set of mass ratios of non-spinning black hole binaries and a host of multipole modes corresponding to spherical harmonic indices $l\le 4$ and $m\le 3.$ We find that the first overtone is most important in the leading mode for a given $m$ and decreases for sub-dominant modes. The contribution of the fundamental mirror mode is most significant for $m=1$ and increases with mass ratio, although the model systematics are not affected significantly by mirror modes. Mode-mixing is the dominant effect for the sub-leading modes of a given $m$ and minimally affects the leading mode.

Cited by in corpus (6)

• Analysis of Ringdown Overtones in GW150914
• High Precision Ringdown Modeling: Multimode Fits and BMS Frames
• Possible Causes of False General Relativity Violations in Gravitational Wave Observations
• High-overtone fits to numerical relativity ringdowns: beyond the dismissed n=8 special tone
• Thermal Ringdown of a Kerr Black Hole: Overtone Excitation, Fermi-Dirac Statistics and Greybody Factor
• Black hole spectroscopy horizons for current and future gravitational wave detectors