Article image

Most distant black hole merger ever witnessed found by Webb

In an unprecedented feat of cosmic observation, the James Webb Space Telescope (JWST) has revealed the most distant black hole merger ever observed.

Astronomers utilized this advanced observatory to detect an ongoing merger of two galaxies, along with their central supermassive black holes, dating back to when the universe was a mere 740 million years old.

Spectacular black hole merger

Historically, supermassive black holes have been identified in the majority of the massive galaxies in the local universe, including our own Milky Way.

These astronomical phenomena are believed to have significantly influenced the development of their host galaxies. Despite our extensive knowledge, the rapid and early growth of these black holes remains a mystery.

The new findings, published in the Monthly Notices of the Royal Astronomical Society, suggest that these growth processes began much earlier and progressed much faster than previously believed.

The recent observations by the JWST provide a glimpse into the early universe, showcasing the merger of two galaxies identified as system ZS7.

This event is critical because it supports the theory that black holes experienced significant growth very early in the history of the universe.

Insights from the depths of space

The distinctive spectrographic features of massive, matter-accreting black holes have allowed astronomers to pinpoint them even in the distant universe.

“We found evidence for very dense gas with fast motions in the vicinity of the black hole, as well as hot and highly ionized gas illuminated by the energetic radiation typically produced by black holes in their accretion episodes,” said lead author Hannah Übler of the University of Cambridge in the UK.

She highlighted the role of Webb’s sharp imaging capabilities, which enabled the team to spatially separate the two black holes involved in the merger.

Roberto Maiolino, another team member, noted the challenges in measuring the masses of these distant objects. He explained that while one of the black holes has a confirmed mass of 50 million times that of the sun, estimating the mass of the second, which is shrouded in dense gas, is more complex.

Broader impact of early black hole mergers

These findings also hint at the role of mergers in the rapid growth of black holes during the cosmic dawn. “Our findings suggest that merging is an important route through which black holes can rapidly grow, even at cosmic dawn,” Übler explained.

This observation is supported by other discoveries of active, massive black holes in the distant universe, underscoring the significant impact these entities have had on galaxy evolution from the beginning.

Pablo G. Pérez-González, another key researcher on the team, compared the stellar mass of the studied system to that of the Large Magellanic Cloud, offering a perspective on the potential evolutionary paths of merging galaxies hosting supermassive black holes.

Hunting black holes with lasers

The study also anticipates the gravitational waves that will be produced once the black holes complete their merger.

Such events will be observable by future gravitational wave observatories, including the upcoming space-based Laser Interferometer Space Antenna (LISA).

“Webb’s results are telling us that lighter systems detectable by LISA should be far more frequent than previously assumed,” shared LISA Lead Project Scientist Nora Luetzgendorf of the European Space Agency. “It will most likely make us adjust our models for LISA rates in this mass range. This is just the tip of the iceberg.”

Webb’s Cycle 3 program

The team has recently been awarded a new Large Programme in Webb’s Cycle 3 of observations, to study in detail the relationship between massive black holes and their host galaxies in the first billion years.

An important component of this program will be to systematically search for and characterize black hole mergers. This effort will determine the rate at which black hole merging occurs at early cosmic epochs.

In addition, it will assess the role of merging in the early growth of black holes and the rate at which gravitational waves are produced from big bang.

Continuing the quest to understand black hole mergers

In summary, the discovery of the earliest known black hole merger, made possible by the Webb Telescope, marks a significant milestone in our understanding of the early Universe and the growth of supermassive black holes.

This fascinating find highlights the rapid evolution of these cosmic giants while paving the way for future research into the relationship between black holes and their host galaxies.

As astronomers continue to explore the mysteries of the cosmos, this discovery serves as a reminder of the incredible potential for new knowledge and the importance of pushing the boundaries of scientific inquiry.

With the promise of future gravitational wave observations and ongoing studies using cutting-edge technology like the JWST, we stand on the brink of a new era in our understanding of the Universe and its most enigmatic inhabitants.

The full study was published in the journal Monthly Notices of the Royal Astronomical Society.


Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and


News coming your way
The biggest news about our planet delivered to you each day