Are astronomers seeing a signal from giant black holes?

World-wide radio telescope network strengthens evidence for signal that may hint at ultra-low frequency gravitational waves

Artist’s impression of the IPTA experiment — an array of pulsars around the Earth embedded in a gravitational wave background from supermassive black hole binaries. The signals from the pulsars measured with a network of global radio telescopes are affected by the gravitational waves and allow for the study of the origin of the background. Image by Carl Knox (OxGrav).

An international team of astronomers has discovered what could be the early sign of a background signal arising from supermassive black holes, observed through low-frequency gravitational waves. These scientists are comparing data collected from several instruments, including the National Science Foundation’s Green Bank Telescope (GBT.)