Astronomers Discover Triple Supermassive Black Holes in Ancient Galaxy via Webb Telescope

Two years ago, a team of astronomers embarked on a mission to map the early cosmos, specifically searching for galaxies containing dual black holes. Their findings exceeded expectations: they discovered a galaxy hosting three.

According to a study published Wednesday in Astronomy & Astrophysics, this marks the first time scientists have identified a young galaxy containing a trio of active supermassive black holes. Two of these black holes are positioned so closely that they appear to be on the brink of a merger.

Lead author Hannah Ubler of the Max Planck Institute for Extraterrestrial Physics noted that while nearly all massive galaxies studied contain central black holes, and some pairs or triplets have been seen in nearby galaxies, this is the first such triplet observed at such a vast distance. Located more than 12.5 billion light-years away, these black holes date back to approximately one billion years after the Big Bang.

This observation provides critical evidence that black holes have been actively growing by consuming gas and stars since the dawn of the universe. “The assumption has always been that these black holes started to grow in the early universe,” Dr. Ubler remarked. “Now we are seeing them in action.”

Such a breakthrough was made possible by the James Webb Space Telescope, which began capturing light from the distant reaches of the universe about four years ago.

Steven Finkelstein, an astronomer at the University of Texas at Austin who was not involved in the study, noted that the Hubble Space Telescope lacked the sensitivity and analytical capabilities of Webb. At Hubble’s resolution, this specific galaxy would have appeared as only a few pixels, making it impossible to discern the three distinct black holes.

To identify the trio, researchers utilized a highly specialized mode of Webb’s near-infrared spectrograph to analyze individual light wavelengths. This allowed them to observe broad hydrogen lines moving at thousands of kilometers per second—a phenomenon caused exclusively by the gravitational pull of a growing supermassive black hole.

The team measured the distances between the three objects and determined that the gravitational pull between two of them is driving them toward a collision. Regarding the third black hole, Julie Comerford, an astrophysics professor at the University of Colorado Boulder, suggested it may eventually join the merger or may have been ejected by a previous merger event.

The mechanism behind how black holes reach such immense sizes remains a central question in astrophysics. While stellar-mass black holes form from collapsing stars, supermassive black holes—like the one in the Milky Way—can reach masses equivalent to millions or billions of suns.

The discovered black holes range from 600,000 to 80 million solar masses. The Webb telescope continues to uncover more of these objects in the early universe than previously anticipated.

Co-author Giovanni Mazzolari, a postdoctoral researcher at Max Planck, stated that several theories exist regarding how these massive objects formed so rapidly. Hypotheses include them being born with high mass, consuming matter at extreme rates, or the frequency of black hole mergers contributing to their growth.

Dr. Ubler calculates that the merger of the two closest black holes could occur in approximately 700 million years.

Source link