Constraining black hole mimickers with gravitational wave observations

TL;DR

This paper explores how gravitational wave observations can distinguish black hole mimickers from true black holes by constraining their tidal deformabilities and equations of state, using Bayesian analysis.

Contribution

It introduces a Bayesian framework to constrain the properties of black hole mimickers with gravitational wave data, focusing on tidal deformability measurements.

Findings

Tidal deformability measurements can differentiate black hole mimickers from true black holes.

Constraints on the equation of state can rule out certain models of exotic compact objects.

Bayesian analysis effectively limits the parameter space of potential black hole mimickers.

Abstract

LIGO and Virgo have recently observed a number of gravitational wave (GW) signals that are fully consistent with being emitted by binary black holes described by general relativity. However, there are theoretical proposals of exotic objects that can be massive and compact enough to be easily confused with black holes. Nevertheless, these objects differ from black holes in having nonzero tidal deformabilities, which can allow one to distinguish binaries containing such objects from binary black holes using GW observations. Using full Bayesian parameter estimation, we investigate the possibility of constraining the parameter space of such "black hole mimickers" with upcoming GW observations. Employing perfect fluid stars with a polytropic equation of state as a simple model that can encompass a variety of possible black hole mimickers, we show how the observed masses and tidal deformabilities of a binary constrain the equation of state. We also show how such constraints can be used to rule out some simple models of boson stars.