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The search for the missing gravitational signal

27 March 2023
The study has been published in The Astrophysical Journal

Every year, hundreds of thousands of pairs of black holes merge in a cosmic dance that emits gravitational waves in every direction. Since 2015, the large ground-based LIGO, Virgo and KAGRA interferometers have made it possible to detect these signals, although only about a hundred such events, an infinitesimal fraction of the total, have been observed. Most of the waves remain 'indistinguishable', superimposed and added together, creating a flat, diffuse background signal that scientists call the 'stochastic gravitational wave background' (SGWB). New SISSA research, published in The Astrophysical Journal, proposes using a constellation of three or four space interferometers to map the flat and almost perfectly homogeneous background in a search for ripples. These small fluctuations, known to scientists as anisotropies, hold the information needed to understand the distribution of gravitational wave sources on the largest cosmological scale.



Image: Simon Barke (University of Florida)