IGFAE leads a proposal to redefine the analysis of gravitational waves

Juan Calderón Bustillo, ‘La Caixa Junior Leader’ researcher and ‘Marie Curie Fellow’ at the Galician Institute of High Energy Physics (IGFAE), a member of the CIGUS Network, an initiative launched by the regional government (Xunta de Galicia) that groups together centres of accredited scientific excellence within the Galician university system, has published an article addressing more than 50 years of study in one of astrophysics’ most promising fields: gravitational waves. In an article published in Physical Review X, the authors ‘flip over’ the complex calculations involved in obtaining information about these events. The work is the result of a collaboration agreement between IGFAE, the University of Valencia and the Chinese University of Hong Kong.

What are gravitational waves and how are they detected?

Gravitational waves are ripples in the fabric of spacetime that travel at the speed of light and are produced during some of the most violent events in the Universe, such as black-hole mergers or explosions of stars (supernovae). They were predicted by Albert Einstein more than a hundred years ago, but it was not until 2015 that they were directly observed thanks to the LIGO (in which IGFAE was involved) and Virgo experiments.

These events are measured with a combination of two tools: data collected by the LIGO and Virgo detectors are used and compared with templates or theoretical models that describe the expected waves for each possible source of these waves, which can be simulated with supercomputers. Essentially, it all works in a manner similar to the apps that guess which song we are listening to by activating the microphone on our cell phone.

Integrals, derivatives, theoretical simulations and detector information

“One of the problems of the entire process is that most of the simulations that are performed are not able to give us directly the space-time ‘jitter’ that the detectors read. Instead, they give us something equivalent to their acceleration, which forces scientists to calculate two integrals for the simulations,” explained Juan Calderón, who has recently received the prestigious Ramón y Cajal scholarship from Spain’s State Research Agency.

Dr Isaac Wong, from the Chinese University of Hong Kong and co-leader of the study added, “Although calculating integrals may seem a simple operation, it can lead to errors that we are only capable of controlling in relatively simple cases, such as the black hole mergers that LIGO and Virgo have detected to date”.