An international team of astrophysicists, including researchers from Penn State Abington, have used large radio telescopes to observe a collection of “cosmic clocks” in our galaxy to find evidence for gravitational waves that oscillate with periods of years to decades, according to a set of papers published in the Astrophysical Journal Letters.

The gravitational-wave signal was observed in 15 years of data acquired by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) Physics Frontiers Center (PFC), a collaboration of more than 190 scientists from the U.S. and Canada.

Ann Schmiedekamp and Carl Schmiedekamp, both physicists from Penn State Abington, have been a part of the NANOGrav collaboration for four years.

“This evidence of gravitational waves with oscillations of years to decades, opens a new window to our universe,” they said. “We have been only a small part of an immense effort with hundreds of outstanding scientists.”

While earlier results from NANOGrav uncovered an enigmatic timing signal common to all the pulsars they observed, they said, it was too faint to reveal its origin. The 15-year data release demonstrates that the signal is consistent with slowly undulating gravitational waves passing through our galaxy.

Ann and Carl Schmiedekamp have been primarily involved in NANOGrav’s outreach activities. NANOGrav has programs for high school students and undergraduates through the Pulsar Science Collaboration and the two researchers have been advisers to the PSC advanced group on giant pulses and helped with other PSC activities.

They have also run an ongoing undergraduate research program in pulsar astronomy at the Abington campus through the ACURA program.

Read more about the astrophysicists on Penn State Abington’s website.

More about the revelations from NANOGrav.