Are gravitational wave ringdown echoes always equal-interval ?

TL;DR

This paper challenges the common assumption that gravitational wave ringdown echoes have constant intervals, showing that in certain scenarios like wormhole collapse, the intervals increase over time, affecting detection strategies.

Contribution

It introduces the idea that GW echoes may have non-constant intervals, especially in wormhole-to-black hole transitions, expanding the understanding of potential GW signals.

Findings

Echo intervals can increase over time in wormhole collapse scenarios.

Detection of non-constant interval echoes requires different analysis methods.

Implications for LIGO/Virgo detection strategies are discussed.

Abstract

Gravitational wave (GW) ringdown waveforms may contain "echoes" that encode new physics in the strong gravity regime. It is commonly assumed that the new physics gives rise to the GW echoes whose intervals are constant. We point out that this assumption is not always applicable. In particular, if the post-merger object is initially a wormhole, which slowly pinches off and eventually collapses into a black hole, the late-time ringdown waveform exhibit a series of echoes whose intervals are increasing with time. We also assess how this affects the ability of Advanced LIGO/Virgo to detect these new signals.