Probing Gravity with Spacetime Sirens

TL;DR

This paper discusses how future gravitational wave observations from space-based detectors like LISA can serve as probes for modified gravity theories and dark energy by analyzing luminosity distances and potential signatures in cosmological-scale signals.

Contribution

It introduces the concept of using spacetime sirens as a novel method to test large-scale modifications of gravity and dark energy models through gravitational wave measurements.

Findings

Potential to detect extra-dimensional leakage of gravity

Gravitational Hubble diagram can reveal deviations from standard cosmology

Various signatures in gravitational signals over cosmological distances

Abstract

A gravitational observatory such as LISA will detect coalescing pairs of massive black holes, accurately measure their luminosity distance and help identify a host galaxy or an electromagnetic counterpart. If dark energy is a manifestation of modified gravity on large scales, gravitational waves from cosmologically-distant spacetime sirens are direct probes of this new physics. For example, a gravitational Hubble diagram based on black hole pair luminosity distances and host galaxy redshifts could reveal a large distance extra-dimensional leakage of gravity. Various additional signatures may be expected in a gravitational signal propagated over cosmological scales.