The state-of-the-art Webb Space Telescope has spotted the most distant black hole merger to date, which occurred when the universe was just 740 million years old. This is the first time that astronomers have witnessed a merger this early in the history of the universe, making it a record.
Black holes are massive objects scattered throughout our universe; their gravitational fields are so strong that even light cannot escape their event horizons. Black hole mergers are exactly what they sound like: slow, terrible dances between two objects, often at the centers of their respective galaxies, eventually merging into a single object.
The recent observation of the merger was made by an astronomy team in May 2023 using the NIRSpec-IFU instrument on the Webb telescope. The cosmic encounter of the holes occurred when the universe was about three-quarters of a billion years old (for reference, the universe is now 13 billion years older than that!), in a galactic system called ZS7.
The merger was spotted using spectrographic features of accreting black holes (those actively absorbing matter) that are not visible to ground-based telescopes. Fortunately, Webb is in L2, a region of space 1 million kilometers from Earth, where he can peer even deeper into the universe.
![From left to right: a field containing ZS7, a smaller region in the field, and ZS7.](https://i.kinja-img.com/image/upload/c_fit,q_60,w_645/9947a8e7a3318f75692d5364040f8d48.jpg)
“Our results suggest that merger is an important pathway by which black holes can grow rapidly, even at the cosmic dawn,” Hannah Übler, an astronomer at the University of Cambridge and lead author of the study, said in an ESA study. release. “Along with Webb's other discoveries of active, massive black holes in the distant Universe, our results also show that massive black holes have shaped the evolution of galaxies from the very beginning.”
Webb's vision is so sharp that the team was able to spatially separate the two black holes, revealing some of their physical characteristics. One of the holes is about 50 million times the mass of the Sun, while the other is obscured by a dense cloud of gas. The team's full document on the discovery was published today in the Monthly Notices of the Royal Astronomical Society.
When black holes merge, they send gravitational shock waves which compress and expand space-time over billions of light years. These waves are detected by observatories such as those managed by the LIGO-Virgo-KAGRA Collaboration, part of which The first gravitational waves were detected in 2015.
However, a brighter future is on the horizon for understanding the gravitational universe. The SEC is officially adopted the Laser Interferometer Space Antenna (LISA), a space gravitational wave observatory, in January, paving the way for the spacecraft's eventual launch and operation.
“Webb's results tell us that lighter systems detectable by LISA should be much more common than previously thought,” said Nora Luetzgendorf, lead LISA project scientist at the European Space Agency, in the same release. . “This will most likely require us to adjust our models for LISA rates in this mass range. This is just the tip of the iceberg. »
Together, the next generation of space telescopes reveals the first black holes, but also their frequency in the universe. Solving the puzzles of black holes – how they grow, interact with and shape surrounding regions – will help astrophysicists understand some of the most fundamental mysteries of the universe.