Constraining gravity with eccentric gravitational waves: projected upper bounds and model selection
Year: 2020
Type: article
Abstract: Gravitational waves allow us to test general relativity in the highly dynamical regime. While current observations have been consistent with waves emitted by quasi-circular binaries, eccentric binaries may also produce detectable signals in the near future with ground- and space-based detectors. We here explore how tests of general relativity scale with the orbital eccentricity of the source during the inspiral of compact objects up to e ∼ 0.8. We use a new, third post-Newtonian-accurate, eccentric waveform model for the inspiral of compact objects, which is fast enough for Bayesian parameter estimation and model selection, and highly accurate for modeling moderately eccentric inspirals. We derive and incorporate the eccentric corrections to this model induced in Brans–Dicke theory and in Einstein–dilaton–Gauss–Bonnet gravity at leading post-Newtonian order, which suggest a straightforward eccentric extension of the parameterized post-Einsteinian formalism. We explore the upper limits that could be set on the coupling parameters of these modified theories through both a confidence-interval- and Bayes-factor-based approach, using a Markov-Chain Monte Carlo and a trans-dimensional, reversible-jump, Markov-Chain Monte Carlo method. We find projected constraints with signals from sources with e ∼ 0.4 that are one order of magnitude stronger than that those obtained with quasi-circular binaries in advanced LIGO. In particular, eccentric gravitational waves detected at design sensitivity should be able to constrain the Brans–Dicke coupling parameter ω ≳ 3300 and the Gauss–Bonnet coupling parameter α 1/2 ≲ 0.5 km at 90% confidence. Although the projected constraint on ω is weaker than other current constraints, the projected constraint on α 1/2 is 10 times stronger than the current gravitational wave bound.
Source: Classical and Quantum Gravity
Authors: Blake Moore, Nicolás Yunes
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: THIS PROPOSAL IS FOCUSED ON DEVELOPING THE EXPERIMENTAL-RELATIVITY SCIENCE CASE FOR THE LASER INTERFEROMETER SPACE ANTENNA (LISA). WE PROPOSE TO EXPLORE TESTS OF GENERAL RELATIVITY WITH LISA GRAVITATIONAL WAVE DATA USING DIFFERENT ASTROPHYSICAL POPULATION MODELS AND ASTROPHYSICAL SOURCES TO FORECAST WHAT WILL BE POSSIBLE IN THE ERA OF SPACE-BASED DETECTORS. WE WILL CREATE AND DEVELOP TOOLS TO CARRY OUT CONSISTENCY CHECKS OF EINSTEIN'S THEORY AND TO SEARCH FOR MODIFIED GRAVITY ANOMALIES WITH LISA DATA. WE WILL EXPLORE HOW THE STRENGTH OF THESE TESTS VARIES WITH POPULATION MODELS AND WITH ASTROPHYSICAL SOURCES MAPPING OUT THE THEORY SPACE THAT WILL BE CONSTRAINABLE WITH LISA. WE WILL ALSO EXPLORE THE STRENGTH OF COMBINING LISA DATA WITH GROUND-BASED GRAVITATIONAL WAVE OBSERVATIONS TO CARRY OUT TESTS OF EINSTEIN'S THEORY WITH MULTI-WAVELENGTH OBSERVATIONS. THE PROPOSED WORK IS OF DIRECT RELEVANCE TO NASA'S STRATEGIC MISSION TO BETTER UNDERSTAND THE UNIVERSE THROUGH OBSERVATION AND TO NASA'S MISSION OF DISCOVERY AND KNOWLEDGE. THE REGION OF THE UNIVERSE WHERE GRAVITY IS VERY STRONG AND DYNAMICALLY CHANGING (THE EXTREME GRAVITY UNIVERSE) IS ONE OF THE LAST UNTURNED STONES. THIS IS IN PART BECAUSE EXTREME GRAVITY OBJECTS LIKE BLACK HOLES ARE DIFFICULT TO RESOLVE DUE TO THEIR SIZE AND DISTANCE FROM EARTH. NASA'S INVESTMENT IN SPACE-BORNE GRAVITATIONAL WAVE ASTROPHYSICS AS A PARTNER TO ESA IS AIMED AT RESOLVING SUCH OBJECTS AND FOR THE FIRST TIME EXPLORING THE EXTREME GRAVITY UNIVERSE IN DETAIL. THE FOCUS OF THIS PROPOSAL IS TO AID IN THIS ENDEAVOR BY DEVELOPING THE UNDERSTANDING NEEDED TO EXTRACT THE MOST INFORMATION ABOUT THEORETICAL PHYSICS AND MODIFIED GRAVITY CONSTRAINTS FROM LISA DATA., G5995024112
OpenAlex ID: W3006148769