Ibadan, 20 May 2024. – An international team of astronomers has used the NASA/ESA/CSA James Webb Space Telescope to find evidence for an ongoing merger of two galaxies and their massive black holes when the Universe was only 740 million years old. This marks the most distant detection of a black hole merger and the first time researchers have detected this phenomenon so early in the Universe.
Astronomers have found supermassive black holes with masses of millions to billions times that of the Sun in most massive galaxies in the local Universe. Furthermore, these black holes have likely had a major impact on the evolution of the galaxies they reside in. However, scientists still don’t fully understand how these objects became so massive. As a result, the finding of gargantuan black holes already in place in the first billion years after the Big Bang indicates that such growth must have happened rapidly, and very early.
The new Webb observations have consequently provided evidence for an ongoing merger of two galaxies and their massive black holes when the Universe was just 740 million years old. Massive black holes that are actively accreting matter have distinctive spectrographic features that allow astronomers to identify them. For very distant galaxies, like those in this study, these signatures are inaccessible from the ground and are only detectable with Webb.
Explaining the discovery, lead author Hannah Übler of the University of Cambridge in the United Kingdom, said, “Our findings suggest that merging is an important route through which black holes can rapidly grow, even at cosmic dawn. Together with other Webb findings 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.”
