Not quite black holes at LIGO

TL;DR

This paper presents evidence suggesting that some gravitational wave signals from LIGO may originate from objects that are not quite black holes, based on a resonance spectrum analysis and consistency checks across multiple events.

Contribution

It introduces an updated search strategy targeting the resonance spectrum of not quite black holes and applies it to multiple LIGO events, providing new evidence for their possible existence.

Findings

Indications of signals consistent with not quite black holes across multiple events

Support from the GW170729 event with largest mass and spin

Self-consistent resonance patterns observed in the data

Abstract

We provide more evidence of not quite black holes at LIGO. We update and streamline our previous search strategy and apply it to the ten black hole merger events and the one neutron star merger event. The strategy is aimed at the evenly spaced resonance spectrum expected from not quite black holes, given that at low frequencies the radial wave equation describes the modes of a stretched 1D cavity. We describe various indications of the self-consistency of the apparent signals across all events in the context of a simple theoretical model. The merger with the largest final mass, spin and redshift, GW170729, provides additional interesting support.