3 days after GW170814...

Here is my way to celebrate the Nobel Prize in Physics 2017!

I try to show below the challenge LIGO and Virgo collaborations face to find out a gravitational wave signal originating from the coalescence of not large stellar black holes (like the recent GW170814)) but a neutron star-black hole pair with fiducial mass and spin parameters (like the ones studied to build the templates used in data analysis and not too far from the ones expected to make the final black hole surrounded by a disk of matter the potential progenitor of a short gamma ray burst like GRB170817A, an already reported event possibly located in NGC4993 at a distance of roughly 40 Mpc).  

Computed* Fourier amplitude of the gravitational wave from the coalescence of the two non-precessing spinning black holes at the origin of GW170814. The inspiral region is shown in red, the merger is shown in green, and the ringdown is shown in blue. The amplitude spectral density for the two LIGO detectors (Livingston and Hanford) and Virgo are also shown (as a dot-dashed line, dot line and dashed line respectively).

Computed and estimated** Fourier amplitude of the gravitational wave from the coalescence of a neutron star and a spinning black hole as the one that could be at the origin of a short gamma ray burst like GRB170814A. The inspiral region (red line) would be the same as for two black holes with identical parameters but there would be no merger signal (shown in green) due to the neutron star tidal disruption, and the ringdown would be redshifted (arrow) compared to the signal (in blue) with two black holes. The (smoothed) amplitude spectral density for the two LIGO detectors (Livingston and Hanford) and Virgo are also shown (as dot-dashed line, dot line and dashed line respectively).

* Computation proceeded with the Wolfram demonstration project (contributed by: Satya Mohapatra): Gravitational Waves from Non-precessing Spinning Binary Black Hole Coalescence

** (Crude!) Estimation based on fig. 1 from: Aligned spin neutron star-black hole mergers: a gravitational waveform amplitude model