Astronomers are one step closer to observing gravitational waves from orbiting pairs of supermassive black holes in distant galaxies, all thanks to NASA's Fermi Gamma-ray Space Telescope - a powerful space-based observatory that detects gamma rays, the most energetic form of light.
An international team of scientists analysed over a decade of Fermi data collected from pulsars - rotating neutron stars, but they didn't find any waves. However, they believe that with more observations, these waves may be within Fermi's reach.
NASA defines gravitational waves as ripples in space-time travelling at light speed. They are created when massive objects accelerate.
"We kind of surprised ourselves when we discovered Fermi could help us hunt for long gravitational waves. It's new to the fray – radio studies have been doing similar searches for years. But Fermi and gamma rays have some special characteristics that together make them a very powerful tool in this investigation," says Matthew Kerr, a research physicist at the U.S. Naval Research Laboratory in Washington.
Kerr and his team are hunting for waves that are light-years, or trillions of miles, long and take years to pass Earth. To detect these waves, scientists need galaxy-sized detectors called pulsar timing arrays that perform long-term monitoring of millisecond pulsars at radio wavelengths.
As long gravitational waves pass between one of these pulsars and Earth, they delay or advance the light arrival time by billionths of a second. By looking for a specific pattern of pulse variations among pulsars of an array, scientists expect they can reveal gravitational waves rolling past them, NASA said in a release.
Unlike radio pulsar timing arrays, gamma-ray PTAs, don't suffer from interstellar effects, providing both a complementary probe and an independent confirmation of the radio results.
"The Fermi results are already 30% as good as the radio pulsar timing arrays when it comes to potentially detecting the gravitational wave background. With another five years of pulsar data collection and analysis, it'll be equally capable with the added bonus of not having to worry about all those stray electrons," says Aditya Parthasarathy, a researcher at the Max Planck Institute for Radio Astronomy in Bonn, Germany.
The findings of the study, co-led by Kerr and Parthasarathy, have been published in the journal Science.
https://news.google.com/__i/rss/rd/articles/CBMiiwFodHRwczovL3d3dy5kZXZkaXNjb3Vyc2UuY29tL2FydGljbGUvc2NpZW5jZS1lbnZpcm9ubWVudC8yMDA3MTg2LW5hc2EtdGVsZXNjb3BlLWh1bnRzLWZvci1sb25nLWdyYXZpdGF0aW9uYWwtd2F2ZXMtZnJvbS1tb25zdGVyLWJsYWNrLWhvbGVz0gEA?oc=5
2022-04-18 11:38:09Z
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