Astrophysicists consider computer models to predict and see how often galaxies merge and form super massive hole binaries. These models are useful for simplifying assumptions about how black hole binaries evolve. Using this information, the scientists are able to improve their assumptions about black hole regarding the galaxy merges and constraints.

Ellis says, “After nine years of observing a collection of MSPs, we haven’t detected the stochastic background but we are beginning to rule out many predictions based on current models of galaxy evolution. We are now at a point where the non-detection of gravitational waves is actually improving our understanding of black hole binary evolution.”

“Pulsar timing arrays like NANOGrav are making novel observations of the evolution and nature of our Universe,” says Sarah Burke Spolaor, Jansky Fellow at the National Radio Astronomy Observatory (NRAO) in Soccoro, New Mexico, and a co-author on the paper.

The two possible interpretations of non-detection according to Spolaor is, “Some supermassive black hole binaries may not be in circular orbits or are significantly interacting with gas or stars. This would drive them to merge faster than simple models have assumed in the past.”

“These new results from NANOGrav have the most important astrophysical implications yet,” said Scott Ransom, an astronomer with NRAO in Charlottesville, Virginia. “As we improve our detection capabilities, we get closer and closer to that important threshold where the cosmic murmur begins to be heard. At that point, we’ll be able to perform entirely new types of physics experiments on cosmic scales and open up a new window on the Universe, just like LIGO just did for high-frequency gravitational waves.”

In 2015, NANO grav was awarded $14.5 million by the National Science Foundation. “The Physics Frontier Centers bring people together to address frontier science, and NANOGrav’s work in low-frequency gravitational wave physics is a great example,” said Jean Cottam Allen, the NSF program director