An international collaboration of European astronomers, together with Indian and Japanese colleagues, including scientists from the Westerbork Synthesis Radio Telescope (WSRT), Max Planck Institute for Radio Astronomy (MPIfR), Gravitational Physics (Albert Einstein Institute, AEI) and others have published the results of more than 25 years of observations from six of the World's most sensitive radio telescopes in Europe and India.
Along with other international collaborations, the European and Indian Pulsar Timing Arrays have independently found evidence for ultra-low-frequency gravitational waves, expected to come from pairs of supermassive black holes found in the centres of merging galaxies.
These results are a crucial milestone in opening a new, astrophysically rich window in the gravitational wave spectrum.
Read more in an Astron article Pulsar clocks open new window on gravitational waves, in the MPIfR article A new view of the Universe and in the INAF article "Pulsars reveal the breathing of space-time".
Image: © Daniëlle Futselaar (artsource.nl) / MPIfR; A cosmic population of binary supermassive black holes generates a background of gravitational waves. Pulsars are rapidly rotating neutron stars and are the most precise clocks in the Universe. When a gravitational wave passes the Pulsar Timing Array, the arrival time of the pulses on Earth is affected by a tiny amount of less than 100 nanoseconds. The largest telescopes on Earth are used to precisely monitor the rotating ticks of these pulsars over decades to reveal the faint echoes of distant black holes.
