A Rømer time-delay determination of the gravitational-wave propagation speed

Abstract

In 1676 Olaus Rømer presented the first observational evidence for a finite light velocity $\cem$. He formed his estimate by attributing the periodically varying discrepancy between the observed and expected occultation times of the Galilean satellite Io by its planetary host Jupiter to the time it takes light to cross Earth's orbital diameter. Given a stable celestial clock that can be observed in gravitational waves the same principle can be used to measure the propagation speed $\cgw$ of gravitational radiation. Space-based "LISA"-like detectors will, and terrestrial LIGO-like detectors may, observe such clocks and thus be capable of directly measuring the propagation velocity of gravitational waves. In the case of space-based detectors the clocks will be galactic close white dwarf binary systems; in the case of terrestrial detectors, the most likely candidate clock is the periodic gravitational radiation from a rapidly rotating non-axisymmetric neutron star. Here we evaluate the accuracy that may be expected of such a Rømer-type measurement of $\cgw$ by foreseeable future space-based and terrestrial detectors. For space-based, LISA-like detectors, periodic sources are plentiful: by the end of the first year of scientific operations a LISA-like detector will have measured $\cgw$ to better than a part in a thousand. Periodic sources may not be accessible in terrestrial detectors available to us in the foreseeable future; however, if such a source is detected then with a year of observations we could measure $\cgw$ to better than a part in a million.

12 pages, 1 figure, submitted to PRD

References in corpus (3)

• Detector configuration of KAGRA - the Japanese cryogenic gravitational-wave detector
• Use and Abuse of the Fisher Information Matrix in the Assessment of Gravitational-Wave Parameter-Estimation Prospects
• The LISA verification binaries

Cited by in corpus (9)

• Testing modified gravity at cosmological distances with LISA standard sirens
• Speed of Gravitational Waves and the Fate of Scalar-Tensor Gravity
• Dark Energy in light of Multi-Messenger Gravitational-Wave astronomy
• Measuring Speed of Gravitational Waves by Observations of Photons and Neutrinos from Compact Binary Mergers and Supernovae
• Measuring the propagation speed of gravitational waves with LISA
• First all-sky search for continuous gravitational-wave signals from unknown neutron stars in binary systems using Advanced LIGO data
• Apparent Superluminality of Lensed Gravitational Waves
• Probing cosmological fields with gravitational wave oscillations
• Constraining the propagation speed of gravitational waves with compact binaries at cosmological distances