JWST spots three black holes in one galaxy for first time

An international team of astronomers has discovered three actively accreting supermassive black holes coexisting in a single galaxy more than 12.5 billion light-years from Earth, marking the first time such a trio has been identified in the distant universe.

A Cosmic First

The findings, published Wednesday in the journal Astronomy & Astrophysics, are based on observations of the galaxy J0148-4214 made with the James Webb Space Telescope's Near-Infrared Spectrograph in its Integral Field Unit mode. The galaxy existed roughly 1.2 billion years after the Big Bang, at a redshift of about 5.02.mpg+1

"This is the first evidence of three active black holes in a single galaxy in the distant Universe," said Hannah Übler, research group leader at the Max Planck Institute for Extraterrestrial Physics (MPE) and lead author of the study.mpg

Two of the black holes sit near the galactic center, separated by only about 620 light-years, while a third lies roughly 5,500 light-years from the center. Their masses are approximately 80 million, 2 million, and 0.6 million times that of the Sun. The smallest of the three is accreting matter at a rate that exceeds the Eddington limit — the theoretical maximum predicted by standard models of black hole growth.miragenews+1

Detecting the Invisible

The team identified the black holes through spectral fingerprints of hydrogen atoms moving at high velocities in the gravitational pull of the black holes. To disentangle the two closely spaced central sources, the researchers employed spectro-astrometry, a technique that measures precise spatial shifts in line emission. Without the spatially resolved data provided by the JWST instrument, only one of the three black holes would likely have been detected.mpg

Alternative explanations — including supernovae, shocks, stellar winds, or very massive stars — were ruled out through additional spectral analysis.mpg

Implications for Black Hole Growth

The central pair is expected to merge within the next few hundred million years, as reported by the New York Times. "They suggest that black hole merging may be an additional, fast route for their rapid growth in the early Universe," said Roberto Maiolino, professor at the University of Cambridge and co-author of the study.nytimes+1

The third, off-center black hole may be the remnant of a prior galactic merger, displaced by a gravitational recoil kick, or it may be migrating inward toward the center. The total stellar mass of the host galaxy is about 1.3 billion solar masses — meaning the black holes represent a notable fraction of the system's overall mass.mpg

The researchers say the system is a potential precursor to black hole mergers that could one day be observed with upcoming gravitational wave facilities such as LISA, the space-based detector planned by the European Space Agency.miragenews+1