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A West Virginia University researcher at the Center for Gravitational Waves and Cosmology is unveiling an invisible universe of gravitational radiation distorting the spacetime continuum.

Emmanuel Fonseca, assistant professor of astronomy at the WVU Eberly College of Arts and Sciences, uses precisely timed signals from stars called “radio pulsars” to detect gravitational waves generated when massive objects like stars or black holes accelerate. Gravitational waves contain information about phenomena and objects in distant galaxies and could reveal how matter behaves inside neutron stars.

National Science Foundation funding of $416,000 supports the study.

“Gravitational waves permeate everything — the solar system, Earth, us — but only in the past five to eight years have we been able to detect them,” Fonseca said. “They’re a unique window into the universe, distinct from electromagnetic radiation like light, X-rays, ultraviolet. Those forms of radiation are generated by charged particles, while gravitational waves are caused by objects accelerating in space and perturbing space-time.”

According to Fonseca, “all the supermassive black holes in binary systems in the universe are throwing waves at us. The sum impact of those signals is a wobbly, seemingly random pattern called ‘gravitational-wave background.’ As this research improves our sensitivity to that background, we’ll become more sensitive to gravitational waves emanating from galaxies nearby. Once we’ve found local sources of gravitational waves, we can point electromagnetic telescopes toward them and begin to make sense of things, and that will really be fun.”

Einstein theorized gravitational waves in 1916, but it was only last spring that the international research collaboration NANOGrav announced unambiguous evidence of their existence.

“NANOGrav is a team of researchers, including myself, who have been using data from the Green Bank Telescope in Pocahontas County to detect gravitational waves,” Fonseca said. “For years, we worked so hard to find evidence of gravitational waves. Now suddenly we’re not just detecting them but making sense of them.”

The study will merge Green Bank data with data from the CHIME radio telescope in Canada, which Fonseca helped build. The observatories record similar information at different intervals and frequencies.

“Combining the data means we can achieve full coverage of each wave. We can ‘see’ from one trough over the peak and down to the next trough,” he said.

Gravitational waves can stretch across galaxies. They exist in the low-frequency spectrum; thus a year or two could elapse between a radio telescope registering the first peak of a gravitational wave and its second peak. As these waves oscillate through space-time they ripple through cosmos slightly dislodging whatever they encounter.

Pulsars — pairs of rotating neutron stars — allow Fonseca to detect these ripples as they emit radio pulses reaching Earth at precise intervals.

“We use pulsars as detectors; lighthouses in distance,” Fonseca said. “When we see correlated deviations affecting timing across an array it’s sign gravity has passed shrinking squeezing observatory instruments.”

Using pulsars requires understanding both pulsars themselves phenomena like scintillation which affects signal path towards Earth.

“Scintillation seems random historically considered nuisance,” he said adding believes encodes information improving detection accuracy."

Fonseca emphasized integrating Green Bank CHIME pulsar data means astronomers learn more than just about gravity but also calculate masses neutron stars."

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