Highly Eccentric Black Hole Merger Detected for the First Time

For the first time, scientists from the Rochester Institute of Technology (RIT) and the University of Florida believe they have detected a merger of two black holes with eccentric orbits.

According to a paper published in Nature Astronomy, this may help explain how some of the black hole mergers detected by the LIGO Science Collaboration and the Virgo Collaboration are much heavier than previously thought.

Eccentric orbits are a sign that black holes could repeatedly engulf each other in chance encounters in areas densely populated by black holes, such as galactic nuclei. Scientists studied the most massive binary gravitational wave observed to date, GW190521, to determine if the merger had eccentric orbits.

“The estimated masses of the black holes are each more than 70 times the size of our sun, which places them well above the maximum estimated mass currently predicted by the theory of stellar evolution,” said Carlos Lousto, professor of the Faculty of Mathematical Sciences. and member of the CCRG (Center for Computational Relativity and Gravitation) of Rochester. “This is an interesting case to study as a second-generation binary black hole system and opens up new possibilities for black hole formation scenarios in dense star clusters.”

The new research wanted to examine the available data to see if the black holes had highly eccentric orbits before they merged. They found that the merger is best explained by a high-eccentricity precession model. To accomplish this, the team ran hundreds of new full numerical simulations on supercomputers in local and national labs.

“This represents a major advance in our understanding of how black holes merge,” with the amount of new data provided by the fast LIGO and Virgo detectors, we are making new discoveries about the universe at an astonishing rate.”

An extension of this analysis by the same RIT and UFL team used a possible electromagnetic counterpart observed by the Zwicky Transient Facility observing instrument to independently calculate the Hubble cosmological constant with GW150521 as an eccentric binary black hole merger. They found an excellent agreement with the expected values and recently published the work in the Astrophysical Journal