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(ed.). Gravitational waves (IOP, 2001)(422s).

(ed.). Gravitational waves (IOP, 2001)(422s).

(ed.). Gravitational waves (IOP, 2001)(422s).

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Newtonian binary polarization waveforms 345around the direction of the total angular momentum, and angle ξ varies). Thus,the gravitational wave h(t) depends on time only through the two polarizationwaveforms h + (t) and h × (t). In turn, these waveforms depend on time throughthe binary’s orbital phase φ(t) and the orbital frequency ω(t) = dφ(t)/dt. Theorbital phase is defin<strong>ed</strong> as the angle, orient<strong>ed</strong> in the sense of motion, between theascending node N and the direction of one of the particles, conventionally particle1 (thus φ = 0 modulo 2π when the two particles lie along p, with particle 1 at theascending node). In the absence of any radiation reaction, the orbital frequencywould be constant, and so the phase would evolve linearly with time. Becauseof the radiation reaction forces, the actual variation of φ(t) is nonlinear, and theorbit spirals in and shrinks to zero-size to account, via the Kepler third law, forthe gravitational-radiation energy loss. The main problem of the constructionof accurate templates for the detection of inspiralling compact binaries is thepr<strong>ed</strong>iction of the time variation of the phase φ(t). Inde<strong>ed</strong>, because of theaccumulation of cycles, most of the accessible information allowing accuratemeasurements of the binary’s intrinsic parameters (such as the two masses) iscontain<strong>ed</strong> within the phase, and rather less accurate information is available in thewave amplitude itself. For instance, the relative precision in the determination ofthe distance R to the source, which affects the wave amplitude, is less than forthe masses, which strongly affect the phase evolution [6, 7]. Hence, we can oftenneglect the higher-order contributions to the amplitude, which means retainingonly the dominant harmonics in the waveform, which corresponds to a frequencyat twice the orbital frequency.Once the functions φ(t) and ω(t) are known they must be insert<strong>ed</strong> into thepolarization waveforms comput<strong>ed</strong> by means of some wave-generation formalism.For instance, using the quadrupole formalism, which neglects all the harmonicsbut the dominant one, we findh + =− 2Gµc 2 Rh × =− 2Gµc 2 R( ) Gmω 2/3c 3 (1 + cos 2 i) cos 2φ, (17.31)( ) Gmω 2/3c 3 (2 cos i) sin 2φ (17.32)where R denotes the absolute luminosity distance of the binary’s centre of mass;the mass parameters are given bym = m 1 + m 2 ; µ = m 1m 2m ; ν = µ m . (17.33)This last parameter ν, introduc<strong>ed</strong> for later convenience, is the ratio between ther<strong>ed</strong>uc<strong>ed</strong> mass and the total mass, and is such that 0

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