Spacetime is the new matter / vibe

How a 1.3 M neutron star and 4 M⊙  spinning black hole pair gets its groove on... 

... according to state of the art relativistic magnetohydrodynamics simulations and numerical general relativity by the Illinois Relativity group




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. The merger phase of the gravitational wavetrain is characterized by tidal disruption of the neutron star. 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 Black Hole obey the exact Kerr solution. The BHs formed here are surrounded by gaseous disks with small, but nonnegligible, rest mass). Only one polarization mode (hx) is shown. 

In the case {above}, a magnetized neutron star is orbiting a black hole with spin (SBH/MBH2)=0.75 oriented parallel the binary orbital angular momentum. Shown is hx in both hemispheres. Waveforms are plotted in the region of r/M ≥ 60. The evolution is followed through tidal disruption, merger, and ringdown. The matter is evolved by solving the relativistic MagnetoHydroDynamics equations and the gravitational field is evolved by solving the BSSN form of the Einstein field equations. 
Zachariah B. Etienne, Vasileios Paschalidis, Stuart L. Shapiro
University of Illinois at Urbana-Champaign


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