Tracking the precession of compact binaries from their gravitational-wave signal

Dec, 2010
11 pages
Published in:
  • Phys.Rev.D 84 (2011) 024046
e-Print:

Citations per year

2011201520192023202505101520
Abstract: (arXiv)
We present a simple method to track the precession of a black-hole-binary system, using only information from the gravitational-wave (GW) signal. Our method consists of locating the frame from which the magnitude of the (=2,m=2)(\ell=2,|m|=2) modes is maximized, which we denote the 'quadrupole-aligned' frame. We demonstrate the efficacy of this method when applied to waveforms from numerical simulations. In the test case of an equal-mass nonspinning binary, our method locates the direction of the orbital angular momentum to within (Δθ,Δϕ)=(0.05,0.2)(\Delta \theta, \Delta \phi) = (0.05^{\circ},0.2^{\circ}). We then apply the method to a q=M2/M1=3q = M_2/M_1 = 3 binary that exhibits significant precession. In general a spinning binary's orbital angular momentum L\mathbf{L} is \emph{not} orthogonal to the orbital plane. Evidence that our method locates the direction of L\mathbf{L} rather than the normal of the orbital plane is provided by comparison with post-Newtonian (PN) results. Also, we observe that it accurately reproduces similar higher-mode amplitudes to a comparable non-spinning (and therefore non-precessing) binary, and that the frequency of the (=2,m=2)(\ell=2,|m|=2) modes is consistent with the 'total frequency' of the binary's motion. The simple form of the quadrupole-aligned waveform will be useful in attempts to analytically model the inspiral-merger-ringdown (IMR) signal of precessing binaries, and in standardizing the representation of waveforms for studies of accuracy and consistency of source modelling efforts, both numerical and analytical.
  • 04.25.Nx
  • 04.70.Bw
  • 04.30.Db
  • 04.25.dg
  • black hole: binary
  • spin: precession
  • gravitational radiation
  • angular momentum
  • numerical calculations
  • tracks