Waveforms of compact binary inspiral gravitational radiation in screened modified gravity

Abstract

Scalar-tensor gravity, with the screening mechanisms to avoid the severe constraints of the fifth force in the Solar System, can be described with a unified theoretical framework, the so-called screened modified gravity (SMG). Within this framework, in this paper we calculate the waveforms of gravitational-waves (GWs) emitted by inspiral compact binaries, which include four polarization modes, the plus h+, cross h×, breathing h b , and longitudinal hL modes. The scalar polarizations h b and hL are both caused by the scalar field of SMG, and satisfy a simple linear relation. With the stationary phase approximations, we obtain their Fourier transforms, and derive the correction terms in the amplitude, phase, and polarizations of GWs, relative to the corresponding results in general relativity. The corresponding parametrized post-Einsteinian parameters in the general SMG are also identified. Imposing the noise level of the ground-based Einstein Telescope, we find that GW detections from inspiral compact binaries composed of a neutron star and a black hole can place stringent constraints on the sensitivities of neutron stars, and the bound is applicable to any SMG theory. Finally, we apply these results to some specific theories of SMG, including chameleon, symmetron, dilaton and f (R).

State Key Laboratory for Geomechanics and Deep Underground Engineering, School of Mechanics & Civil Engineering, China University of Mining & Technology, Xuzhou 221116, China

“…The sensitivity of a black hole in massive Brans-Dicke theory is s BH = 1 2 [22]. As a result, for a binary black hole system, Γ = S = 0 and the waveforms are identical to that of GR apart from the replacement M c → M c (1 − ξ) which are the same as that in the limit m s → ∞.…”

“…This is a result of the linearized scalar wave equation (16) [19,22]. Each of these two polarizations has two frequency modes.…”

Gravitational Waves in Scalar–Tensor–Vector Gravity Theory

“…The results are consistent with Einstein's gravity as the analysis indicated that the pure tensor polarizations are favored over the scenario of pure vector or scalar polarizations. Nonetheless, the properties of the modified gravity regarding GWs have recently become a topic of increasing interest [19][20][21][22][23]. On the theoretical side, several methods can be employed to analyze the polarization modes of gravity theory.…”

Angular momentum loss for eccentric compact binary in screened modified gravity

“…In previous work [32], we calculated the GWs energy flux in terms of derivatives of multipole moments in SMG, and derived the rate of the orbital energy loss for compact binaries in quasi-circular orbits. Based on it, in the literature [33], we calculated the waveforms of GWs emitted by inspiralling compact binaries. Recently, the eccentric GWs have been widely studied in the literature [34,35].…”