IN a discovery that challenges standard understanding of galaxy evolution, astronomers have identified one of the largest and most cohesive rotating structures in the universe.
This structure, which is a giant filament of matter 50 million light years long, contains rows of galaxies that not only align but also rotate in synchrony with their parent filament.
The research, led by Lyla Jung and Madalina Tudorache of the University of Oxford, was published on December 4 in the journal Monthly Notices of the Royal Astronomical Society.
Filaments and the Cosmic Web
Filaments are threads in the Cosmic Web, a large-scale structure consisting of dark matter mixed with ordinary matter, stretching across the universe. The discovered filaments are located 140 million light years from Earth and have an extraordinary nesting structure.
At its core, there is a row of 14 galaxies rich in hydrogen gas (the fuel for star formation), stretching 5.5 million light years. These arrays are then embedded in larger filaments that are home to around 300 galaxies in total.
Shocking Double Rotation
What makes this structure special is the combination of alignment and rotational motion of the galaxies within it. Imagine if each galaxy rotated around its own axis, but surprisingly, all the galaxies also rotate around the long axis of the filament at a speed of about 110 kilometers per second in the direction of their individual rotation.
“You could liken it to the teacup ride at an amusement park,” explains Lyla Jung.
“Each galaxy is like a spinning teacup, but its entire platform of cosmic filaments is also spinning. This dual motion gives us rare insight into how galaxies get their spin from the larger structures in which they reside,” he continued.
Challenging the Theory of Galactic Evolution
This discovery surprised astronomers because it challenged old models of galaxy formation.
The rotation of galaxies, such as our Milky Way Galaxy, is usually thought to be the legacy of the rotating gas clouds that formed them billions of years ago. However, since then, collisions and mergers with other galaxies should have disrupted that rotation.
This new discovery shows that the rotation of these giant filaments clearly dominates how the galaxies within them rotate.
The filaments may funnel hydrogen gas along their paths, forcing the galaxy to spin and providing new fuel for star formation.
“These filaments are a fossil record of cosmic flows,” says Madalina Tudorache. “These filaments help us understand how galaxies acquire their spin and evolve over time.”
The scientists noted that the galaxies in these filaments appear relatively young and are at an early stage of development. This suggests that the flow of material along filaments can influence the properties of galaxies to a fundamental level, a finding that will lead to important modifications in models of cosmology and galaxy evolution.
This research was carried out using 64 parabolic antennas from the MeerKAT radio telescope in South Africa, combined with optical data from the Dark Energy Spectroscopic Instrument and the Sloan Digital Sky Survey.
The findings are also important for improving the accuracy of future weak lens surveys, such as those to be conducted by the Vera C. Rubin Observatory, which rely on mapping distortions caused by dark matter in the cosmic web.
Source: Space
