First compelling evidence for the gravitational wave background: unprecedented discovery published in The Astrophysical Journal Letters
29 Jun 2023 by Kate Giles
Artist’s interpretation of an array of pulsars being affected by gravitational ripples produced by a supermassive black hole binary in a distant galaxy. Credit: Aurore Simonnet for the NANOGrav Collaboration
New research that could fundamentally change our understanding of the universe has been published in the American Astronomical Society’s (AAS) Astrophysical Journal Letters, which is published in partnership with IOP Publishing.
Astrophysicists using large radio telescopes to observe pulsars in our Galaxy have found evidence for gravitational waves that oscillate with periods of years to decades. The gravitational-wave signal was observed in 15 years of data acquired by a collaboration of more than 190 scientists from the US and Canada known as NANOGrav, who use pulsars to search for gravitational waves. International collaborations using telescopes in Europe, India, Australia and China have independently reported similar results.
While earlier results from NANOGrav uncovered an enigmatic timing signal common to all the pulsars they observed, it was too faint to reveal its origin. The 15-year data release demonstrates that the signal is consistent with slowly undulating gravitational waves passing through our Galaxy.
Physics World have reported on the discovery saying, “…..the amount of background gravitational waves suggests a huge population of binary supermassive black holes in the universe, with hundreds of thousands of pairs, if not millions. This is powerful evidence for models of the hierarchical formation of galaxies, whereby galaxies grow by merging with other galaxies..”
Read NANOGrav’s press release on their website
The findings from NANOGrav are published in a collection of papers in The Astrophysical Journal Letters.
“The NANOGrav 15-year Data Set: Observations and Timing of 68 Millisecond Pulsars,” Joseph Swiggum et al 2023 ApJL 951 L9. doi:10.3847/2041-8213/acda9a
“The NANOGrav 15-Year Data Set: Detector Characterization and Noise Budget,” Jeffrey Hazboun et al 2023 ApJL 951 L10. doi:10.3847/2041-8213/acda88
“The NANOGrav 15-year Data Set: Evidence for a Gravitational-Wave Background,” Sarah Vigeland et al 2023 ApJL 951 L8. doi:10.3847/2041-8213/acdac6
“The NANOGrav 15-year Data Set: Search for Signals from New Physics,” Andrea Mitridate et al 2023 ApJL 951 L11. doi:10.3847/2041-8213/acdc91