Black hole ringdown echoes and howls

Hiroyuki Nakano,Hideyuki Tagoshi,Norichika Sago,Takahiro Tanaka

doi:10.1093/ptep/ptx093

Abstract

Recently the possibility of detecting echoes of ringdown gravitational waves from binary black hole mergers was shown. The presence of echoes is expected if the black hole is surrounded by a mirror that reflects gravitational waves near the horizon. Here, we present slightly more sophisticated templates motivated by a waveform which is obtained by solving the linear perturbation equation around a Kerr black hole with a complete reflecting boundary condition in the stationary traveling wave approximation. We estimate that the proposed template can bring about a |$10\%$| improvement in the signal-to-noise ratio.

Highlights

Direct gravitational wave (GW) detections [1, 2] give us various opportunities to discuss the nature of black holes (BHs)
In the analysis of Ref. [3], a simple template has been used for the analysis of GW echoes in the matched filtering method [see a similar template shown in Eq (24)]
We find that the reflection rate depends on the frequency while the rate adopted in Ref. [3] is independent of the GW frequency

Summary

Introduction

Direct gravitational wave (GW) detections [1, 2] give us various opportunities to discuss the nature of black holes (BHs). We consider a Kerr BH [12] with mass M and spin parameter a, and calculate echo waveforms by solving the linear perturbation equation with a complete reflecting boundary condition in Sect.

Results

Conclusion