Simultaneous bounds on the gravitational dipole radiation and varying gravitational constant from compact binary inspirals

Compact binaries are an important class of gravitational-wave (GW) sources that can be detected by current and future GW observatories. They provide a testbed for general relativity (GR) in the highly dynamical strong-field regime. Here, we use GWs from inspiraling binary neutron stars and binary black holes to investigate dipolar gravitational radiation (DGR) and varying gravitational constant predicted by some alternative theories to GR, such as the scalar-tensor gravity. Within the parametrized post-Einsteinian framework, we introduce the parametrization of these two effects simultaneously into compact binaries' inspiral waveform and perform the Fisher-information-matrix analysis to estimate their simultaneous bounds. In general, the space-based GW detectors can give a tighter limit than ground-based ones. The tightest constraints can reach sigma(B) < 3 x 10(-11 )for the DGR parameter B and sigma((G)overdot)/G < 7 x 10(-9 )yr(-1) for the varying G, when the time to coalescence of the GW event is close to the lifetime of space-based detectors. In addition, we analyze the correlation between these two effects and highlight the importance of considering both effects in order to arrive at more realistic results. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

Compact binaries are important sources of gravitational waves that can be detected by current and future observatories. By studying gravitational waves from binary neutron stars and binary black holes, we can investigate alternative theories to general relativity. The parameterized analysis of the dipolar gravitational radiation and varying gravitational constant provides simultaneous bounds, with space-based detectors offering tighter constraints.