WVU professor, Green Bank Telescope plays key role in observing forces acting in spacetime – WV MetroNews

A West Virginia University professor and the Green Bank Telescope have played a major role in a 15-year effort producing evidence of low-frequency gravitational waves that push and pull the universe.

In essence, for many years, study has focused on how gravitational forces in space affect pulsars. It’s a study of the wobbly, wobbly things about the universe.

Einstein’s theory of general relativity predicts exactly how gravitational waves should affect pulsar signals. By stretching and compressing the fabric of space, gravitational waves affect the timing of each pulse in small but predictable ways, delaying some while advancing others.

These shifts are related for all pulsar pairs in a way that depends on the distance between the two stars in the sky.

Maura McLaughlin

One of the researchers testing this is Dr. Maura McLaughlin, the Eberly Family Distinguished Professor of Physics and Astronomy and director of the WVU Center for Gravitational Waves and Cosmology.

He clarified that the long-term research has provided “significant evidence,” but it’s not definitive. Much more work is yet to come.

“We are not reporting a detection,” McLaughlin said during a press event this week. “Let’s be very careful with our language and call this evidence for gravitational waves.”

McLaughlin was part of an international collaboration dedicated to exploring the low-frequency gravitational-wave universe through the timing of radio pulsars.

“Pulsars are actually very faint radio sources, so we need thousands of hours a year on the world’s largest telescopes to perform this experiment,” McLaughlin said.

The team’s findings were published today in the Astrophysical Journal Letters.

The 15 years of observations came from the Arecibo Observatory in Puerto Rico, the Green Bank Telescope in West Virginia and the Very Large Array in New Mexico.

The millisecond pulsars, the focus of the research, are remnants of extinct massive stars. As they rotate hundreds of times per second, their “lighthouse-like” radio beams are seen as very regular pulses.

Gravitational waves stretch and compress space and time in a characteristic pattern, causing changes in the intervals between pulses that are correlated in all observed pulsars.

Related changes are the specific signal detected by the North American Nanohertz Observatory for Gravitational Waves, founded in 2007. NANOGrav’s most recent dataset offers compelling evidence for gravitational waves with swings over years or decades.

The waves monitored by the observatory are thought to come from orbiting pairs of the most massive black holes in the universe: billions of times more massive than the sun, with dimensions greater than the distance between the sun and the earth.

Future studies of the signals will allow researchers to see the gravitational-wave universe through a new window, providing insight into titanic black holes merging at the hearts of distant galaxies and potentially other exotic sources of low-frequency gravitational waves.

“We will become even more sensitive if we can add more pulsars to the array and, more importantly, if we can gain access to even larger new radio telescopes,” McLaughlin said.

Further research “will tell us a great deal about how galaxies merged and evolved over cosmic time. For example, we think you know, most galaxies are the products and mergers of smaller galaxies. what are the time scales? What’s the astrophysics involved, you know they’re going to be able to answer a lot of these questions, which is really exciting.

McLaughlin was a lead investigator at the start of the collaborative effort, NANOGrav. “We were quite small,” he said, “about a dozen scientists. We have grown a lot since then. We now have 194 members in over 80 institutions in the United States, Canada and 12 other countries.

He said the volume of research is growing slowly, recently growing to the point where scientists could draw conclusions.

“In our last dataset, we saw this common noise source that we were pretty sure was gravitational waves, but we didn’t see the spatial correlations,” he said. “And then we predicted that we should see it in the next dataset, you know, if the spatial correlations were there.”

About three years ago, that evidence became clearer in a preliminary version of the data.

“It was a bit of a strange time, because it was during Covid,” he said. “So everyone was like at home on zoom and I’m embarrassed to say I don’t remember where I was sitting or what I was doing at that exact moment. when I saw it, but I remember being completely blown away.

“Even though we knew it should have been in this data based on the statistics from the last detection and the additional sensitivity we knew we had, we knew it had to be there. Seeing those points like equalizing that corner for the first time was truly a magical moment, honestly. It was so special. And it is the result of a lot of work by many people. so that was really, really wonderful to see.

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