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Feb. 23, 2023 - Research conducted by Dr. Dirk Grupe, 91���� associate professor and chair of the Department of Physics, Geology and Engineering Technology, and colleagues at the Max-Planck-Institute for Radio Astronomy in Germany, has been accepted in the Monthly Notices of The Royal Astronomical Society and the Astrophysical Journal. 

The research shows that one of the universe’s most massive black holes, located at the center of galaxy OJ 287 nearly 5.1 billion light years away, is the size of 100 million solar masses instead of the previously believed 10 billion solar masses. 

"I'm incredibly proud that the collaboration between 91���� and Max-Planck-Institute for Radio Astronomy has led to these significant findings that will alter the way we look at this binary black hole system now,” Dr. Grupe said. 

The international research group, led by Stefanie Komossa from the Max Planck Institute for Radio Astronomy in Bonn, Germany, and including Dr. Grupe, was able to test crucial binary model predictions using multiple observing tools including the Effelsberg radio telescope and the Neil Gehrels Swift Observatory. There were also collaborators from institutions in China, Chile, Canada and Spain. For the first time, an independent black hole mass determination of the system was performed and the amount of matter in a disk surrounding the black hole could be estimated. 

The results show that an exceptionally massive black hole exceeding 10 billion solar masses is no longer needed. Instead, the results favor models with a smaller black hole mass of 100 million solar masses. Several outstanding mysteries, including the apparent absence of the latest big outburst of OJ 287 (which has now been identified) and the much-discussed emission mechanism during the main outbursts, can be solved this way. 

Findings of this research have strong implications for the theoretical modeling of supermassive black hole binary systems and their evolution. There are also implications for understanding the physics of accretion and jet launching near supermassive black holes, for future pulsar timing vs. space-based gravitational wave detection from this system, and a direct spatial resolution of this system with the Event Horizon Telescope or the future SKA Observatory. The findings are presented in two papers published in MNRAS Letters and the Astrophysical Journal.

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