Gravitational Waveforms

The gravitational wavetrain from a compact binary system may be separated into three qualitatively different phases: the inspiral, merger, and ringdown. During the inspiral phase, which takes up most of the binary's lifetime, gravity wave emission gradually reduces the binary separation. When the black holes get close enough, they merge into one black hole. Finally, ringdown radiation is emitted as the distorted black hole settles down to Kerr-like equilibrium (Note: Only in the case of a vacuum spacetime does the spinning BH obey the exact Kerr solution. The BHs formed here are surrounded by gaseous disks with small, but nonnegligible, rest mass). Both polarization modes (h₊ and h_x) are shown.

Mass Ratio = 1:1

In the post-decoupling regime, we have two black holes with equal mass inspiraling towards each other surrounded by a gaseous disk. Shown below are h₊ and h_x in just the lower hemisphere. Waveforms are plotted in the region of $r/M \geq 40$. The evolution is followed through inspiral, merger, and ringdown. Peak wave amplitudes are generated just prior to the final plunge and merger of the black holes.

h₊ Polarization (Lower Hemisphere)

Fig. 3-1: t/M = 417	Fig. 3-2: t/M = 1606	Fig. 3-3: t/M = 1745
Fig. 3-4: t/M = 1832	Fig. 3-5: t/M = 1861	Fig. 3-6: t/M = 1907

h_x Polarization (Lower Hemisphere)

Fig. 3-1: t/M = 325	Fig. 3-2: t/M = 651	Fig. 3-3: t/M = 1264
Fig. 3-4: t/M = 1308	Fig. 3-5: t/M = 1635	Fig. 3-6: t/M = 1851