An international team led by the University of Oxford has discovered one of the largest rotating structures in the universe, a thin chain of galaxies spinning in sync within a larger cosmic filament. Located about 140 million light years from Earth, this structure challenges models of galaxy formation. The findings, published in Monthly Notices of the Royal Astronomical Society, suggest that large-scale cosmic structures influence galaxy spin.
The discovery involves a razor-thin chain of 14 hydrogen-rich galaxies arranged in a line about 5.5 million light years long and 117,000 light years across. This chain sits inside a broader cosmic filament spanning roughly 50 million light years and containing more than 280 galaxies. Observations show that many galaxies in the chain rotate in the same direction as the filament, a pattern stronger than random chance would predict.
Researchers noted that galaxies on opposite sides of the filament's central spine move in opposing directions, indicating the entire structure rotates as one. Models estimate a rotation speed of 110 km/s, with the dense central region having a radius of about 50 kiloparsecs, or 163,000 light years.
Co-lead author Dr. Lyla Jung from the University of Oxford's Department of Physics described the structure: "What makes this structure exceptional is not just its size, but the combination of spin alignment and rotational motion. You can liken it to the teacups ride at a theme park. Each galaxy is like a spinning teacup, but the whole platform—the cosmic filament—is rotating too. This dual motion gives us rare insight into how galaxies gain their spin from the larger structures they live in."
The filament appears young and undisturbed, in a "dynamically cold" state with low internal motion. Its gas-rich galaxies, abundant in hydrogen—the fuel for star formation—offer clues to early galaxy evolution. Co-lead author Dr. Madalina Tudorache, from the Institute of Astronomy at the University of Cambridge and Oxford's Department of Physics, added: "This filament is a fossil record of cosmic flows. It helps us piece together how galaxies acquire their spin and grow over time."
The team used data from South Africa's MeerKAT radio telescope via the MIGHTEE survey, combined with optical observations from the Dark Energy Spectroscopic Instrument and the Sloan Digital Sky Survey. Professor Matt Jarvis, who leads the MIGHTEE survey at Oxford, highlighted the collaboration: "This really demonstrates the power of combining data from different observatories to obtain greater insights into how large structures and galaxies form in the Universe. Such studies can only be achieved by large groups with diverse skillsets."
The research, involving institutions like the University of Cambridge and the South African Radio Astronomy Observatory, was supported by grants including an ERC Advanced Grant and UKRI Frontiers Research Grant. It may refine models for galaxy alignments, aiding future surveys like those from the Euclid spacecraft and the Vera C. Rubin Observatory.