The newly-discovered galaxy filament spans at least 50 million light-years and resides 140 million light-years away. The galaxies are orbiting around the spine of the filament, making this one of the largest rotating structures discovered thus far.
A figure illustrating the rotation of neutral hydrogen (right) in galaxies residing in an extended filament (middle), where the galaxies exhibit a coherent bulk rotational motion tracing the large-scale cosmic web (left). Image credit: Lyla Jung.
Cosmic filaments are the largest known structures in the Universe: vast, thread-like formations of galaxies and dark matter that form a cosmic scaffolding.
They also act as ‘highways’ along which matter and momentum flow into galaxies.
Nearby filaments containing many galaxies spinning in the same direction- and where the whole structure appears to be rotating — are ideal systems to explore how galaxies gained the spin and gas they have today.
They can also provide a way to test theories about how cosmic rotation builds up over tens of millions of light-years.
In a new study, University of Oxford astronomer Lyla Jung and colleagues found 14 nearby galaxies rich in hydrogen gas, arranged in a thin, stretched-out line about 5.5 million light-years long and 117,000 light-years wide.
This structure sits inside a much larger cosmic filament containing over 280 other galaxies, and roughly 50 million light-years long.
Remarkably, many of these galaxies appear to be spinning in the same direction as the filament itself- far more than if the pattern of galaxy spins was random.
This challenges current models and suggests that cosmic structures may influence galaxy rotation more strongly or for longer than previously thought.
The astronomers found that the galaxies on either side of the filament’s spine are moving in opposite directions, suggesting that the entire structure is rotating.
Using models of filament dynamics, they inferred the rotation velocity of 110 km/s and estimated the radius of the filament’s dense central region at approximately 163,000 light-years.
“What makes this structure exceptional is not just its size, but the combination of spin alignment and rotational motion,” Dr. Jung said.
“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 to be a young, relatively undisturbed structure.
Its large number of gas-rich galaxies and low internal motion — a so-called dynamically cold state — suggest it’s still in an early stage of development.
Since hydrogen is the raw material for star formation, galaxies that contain much hydrogen gas are actively gathering or retaining fuel to form stars.
Studying these galaxies can therefore give a window into early or ongoing stages of galaxy evolution.
Hydrogen-rich galaxies are also excellent tracers of gas flow along cosmic filaments.
Because atomic hydrogen is more easily disturbed by motion, its presence helps reveal how gas is funnelled through filaments into galaxies, offering clues about how angular momentum flows through the cosmic web to influence galaxy morphology, spin, and star formation.
“This filament is a fossil record of cosmic flows,” said Dr. Madalina Tudorache, an astronomer at the University of Cambridge and the University of Oxford.
“It helps us piece together how galaxies acquire their spin and grow over time.”
The researchers used data from South Africa’s MeerKAT radio telescope, one of the world’s most powerful telescopes, comprising an array of 64 interlinked satellite dishes.
This spinning filament was discovered using a deep survey of the sky called MIGHTEE.
This was combined with optical observations from DESI and SDSS surveys to reveal a cosmic filament exhibiting both coherent galaxy spin alignment and bulk rotation.
“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,” said University of Oxford’s Professor Matt Jarvis.
The discovery is reported in a paper in the Monthly Notices of the Royal Astronomical Society.
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Madalina N. Tudorache et al. 2025. A 15 Mpc rotating galaxy filament at redshift z = 0.032 Available for Purchase. MNRAS 544 (4): 4306-4316; doi: 10.1093/mnras/staf2005
