Super Gravity Brothers


The GW150914 blackhole merger event recorded by aLIGO, represented in a wavelet (morlet base) spectrogram. This spectrogram was based on the audio file released with the original announcment.

The data from the second detection, GW151226, is another beast entirely in that the signal is very much buried in the noise.

Raw data:


Wavelet Spectrogram: gw151226CWTspec

The LIGO Open Science Center makes these data available, along with signal processing tutorials.

Now to see how the professionals do it:

I used MATLAB’s wavelet toolbox for the visualisations, aided by this example

Gravitational wave observation GW150914 with black hole merger simulation

I couldn’t find anyone that had combined the gravitational wave chirp observed by LIGO with the simulated visualisation of the putative black hole merger by SXS, so I decided to give it a try myself. Consider it to be illustrative, rather than rigorous.

In the first run-through, the LIGO gravitational wave observation from 2015 Sept 14 (audio chirp) is speed and pitch adjusted to match the SXS visualisation. Mergers 2-5 adjust the SXS simulation to match the chirp, alternating between native and pitch-adjusted frequency to cater to human hearing.

LIGO observation:
Abbott, B. P. et al. Observation of Gravitational Waves from a Binary Black Hole Merger. Phys. Rev. Lett. 116, 61102 (2016).

Visualisation modified from Simulating eXtreme Spacetimes (SXS) Project
Source material used under CC-NC-BY licence ( Feel free to reuse and remix, but retain attributions.