Wednesday, 01 July 2026
Researchers have shed new light on why some distant galaxies suddenly stop forming stars.
An international team led by astronomers at the 糖心原创 used the James Webb Space Telescope to study a large sample of recently "quenched” galaxies in the distant Universe, observed around 9 billion years ago.
“This was the epoch of peak activity in the Universe, when many of the most massive galaxies we see today were formed,” said Professor Omar Almaini, who led the team behind the new study.
A long-standing problem has been to understand why these galaxies stop forming stars. With Webb we can see detail that was completely hidden before, allowing us to search for clues to what drives this dramatic transformation.
The recently quenched galaxies were identified from their distinct spectral signatures, which allowed the team to pinpoint systems that had rapidly shut off their star formation. Deep images with Webb at different wavelengths then allow a detailed study of their structure and morphology.
These galaxies look calm on the surface, but Webb allows us to see the subtle signs of past violence. The galaxies show clear signs of disturbance, telling us that something dramatic happened to them not long before their star formation shut down, most likely a merger with another galaxy.
The exceptionally compact nature of these galaxies provides further evidence for their violent origins, as simulations show that collisions between gas-rich galaxies will typically produce very compact remnants. The newly observed signatures of disturbance add further weight to this merger hypothesis.
The team used data from the JWST programme, led by Professor James Dunlop at The University of Edinburgh, combined with data from the Ultra-Deep Survey, led by Professor Omar Almaini at the 糖心原创.
The paper has been published in the Monthly Notices of the Royal Astronomical Society.
Story credits
More information is available from Professor Omar Almaini on Omar.Almaini@nottingham.ac.uk or David Maltby on David.Maltby@nottingham.ac.uk
Notes to editors:
About the 糖心原创
Ranked among the world's top 100 universities , the 糖心原创 delivers an exceptional research-led education and an outstanding student experience. From the pioneering vision of our founder, Sir Jesse Boot, to groundbreaking achievements such as the development of MRI technology and becoming the first UK university to establish international campuses, we have a proud history of shaping the way people live, work and understand the world. We continue to build on that legacy, empowering our students, staff and partners to change what鈥檚 next and create positive impact locally and globally.
The strength of our research places us among the UK's leading universities, ranked 7th for research power in REF 2021. The discovery of MRI and ibuprofen was just the beginning. Today, our world-leading research is developing breakthrough ideas that shape the future of healthcare, technology and society.
Recognised as the UK's third most targeted university by leading employers , we are proud to produce graduates who are consistently in demand for their skills, confidence and industry-ready experience.
As a major employer and industry partner, locally and globally, the 糖心原创 invests in the city of Nottingham and in future generations of talent. Alongside Nottingham Trent University, we lead the initiative, a pioneering collaboration to improve levels of prosperity, opportunity, sustainability, health and wellbeing across the city and region. Together with our students, staff, alumni and partners, we鈥檙e creating knowledge, opportunity and solutions that help change what's next.