From 13 billion light-years across the gulf of space and time, we’ve caught a glimpse of the most distant black hole merger ever discovered.
Using JWSTJust 740 million years after the Big Bang, an international team of astronomers has detected two supermassive black holes and their companion galaxies merging in a colossal cosmic collision.
The discovery is a clue that could help piece together where supermassive black holes came from, early in the universe’s history, and how they grew so large.
„Our findings suggest that coalescence is an important pathway by which black holes can grow rapidly, even at the cosmic dawn.” Astronomer Hannah Abler says of the University of Cambridge in England.
„Along with other web discoveries of active, massive black holes in the distant Universe, our results also show that massive black holes have been shaping the evolution of galaxies from the very beginning.”
Black holes are full of mysteries, and the appearance of massive ones is one of the most fascinating. Small ones, up to 65 times the mass of the Sun, can be explained by supernovae and core collapse of massive stars; The slightly larger ones can be explained by collisions and mergers of these collapsed galactic cores.
Supermassive black holes, millions to billions of times the mass of the Sun, could theoretically grow this way through hierarchical collisions between supermassive and supermassive black holes, but the process takes a long time.
One problem is that we’ve seen supermassive black holes at the beginning of the universe, and they wouldn’t have had time to grow on this slow path.
One possible solution is that the initial „seeds” from which black holes formed were massive to begin with. But even if this is the case (which seems more likely), collisions and mergers played a role in growing these black holes to even larger sizes.
One of JWST’s missions is to use its powerful infrared capabilities to see the cosmic dawn (the first billion years after the universe blinked) with extremely high resolution to discover how the universe formed after the Big Bang. . One of the things astronomers and cosmologists are particularly looking for are supermassive black holes.
During one of its surveys, it picked up a pair of galaxies on a collision course, a system now known as ZS7. At the center of every galaxy is a supermassive black hole. Both black holes are actively growing, a process that causes the dust and gas around them to burn with light.
frameborder=”0″ permission=”accelerometer; automatic; clipboard-write; encrypted-media; Gyroscope; picture-picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” allowfullscreen>
„We found evidence of very dense gas with fast motion in the vicinity of the black hole, as well as hot and highly ionized gas glowing with energetic radiation typically produced by black holes during their accretion episodes.” Übler says.
„Thanks to the unprecedented sharpness of its imaging capabilities, WEBB allowed our team to spatially separate the two black holes.”
The researchers were able to determine that one of the black holes clocks in at about 50 million solar masses. The other was less quantifiable because the surrounding gas and dust was incredibly dense, but probably had a similar mass.
We have seen other such merger systems in the late universe; In fact, mergers are considered to be the most important part of a galaxy’s development. But such an early detection shows that a model that includes both mergers and massive black hole seeds is actually more plausible.
Such massive mergers are thought to create a steady hum of gravitational waves that reverberate throughout the universe.
The wavelengths of these hums are too large to be detected by current gravitational wave instruments (although we have detected them using pulsars), but by detecting mergers that are ongoing at different cosmological epochs, scientists can better estimate the rate at which they occur. Contribution to Universal Hum.
„Our observations provide clear and strong evidence for a supermassive black hole involved in a merger with another galaxy at z = 7.15, 740 million years after the Big Bang.” The researchers write.
„Overall, our results seem to support the scenario of instantaneous black hole mergers in the early Universe, highlighting this as an additional important channel for the early growth of black holes. Together with other recent findings in the literature, this indicates that massive. black hole mergers are common in the distant Universe.”
Published in thesis Monthly Notices of the Royal Astronomical Society.