Galactic mergers like those that formed the Milky Way are violent, high-energy events that can be difficult to study. But these collisions determine the shape and composition of galaxies and trigger the formation of stars and new black holes, so untangling how they play out helps scientists understand the forces that shape the universe.
A recent analysis of a super-bright region of the sky 800 million light years from Earth reveals a merger involving three different types of galaxies, including two that likely contain supermassive black holes called active galactic nuclei (AGN).
This new finding was led by University of Maryland astronomy graduate student Jonathan Williams, who is scheduled to present the analysis of this three-galaxy system today at the 238th meeting of the American Astronomical Society.
In addition to providing insight into what happens when galaxies collide, the finding provides a rare glimpse into a merger involving at least one, and possibly two, AGN. In recent years, astronomers have been able to observe black hole mergers with increasing frequency. But most often, such observations have involved smaller black holes, not the supermassive AGN found at the center of galaxies.
“This find can reveal details about how active galaxies might be triggered and serve as a guide to understanding how supermassive black holes might come together and merge,” said UMD Astronomy Professor Richard Mushotzky, a co-author of the study.
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