Cosmic filaments are cylindrical tendrils of matter hundreds of millions of light-years across. In new research, published in the journal Nature Astronomy, astronomers investigated the possibility that these enormous structures are spinning.
An artist’s impression of cosmic filaments. Image credit: A. Khalatyan/ J. Fohlmeister / Leibniz-Institut für Astrophysik Potsdam.
Although structures in the Universe form on a wide variety of scales, from small dwarf galaxies to large super clusters, the generation of angular momentum across these scales is poorly understood.
“Motivated by the suggestion from the theorist Mark Neyrinck that filaments may spin, we examined the observed galaxy distribution, looking for filament rotation,” said Dr. Noam Libeskind, an astronomer at the Leibniz-Institut für Astrophysik Potsdam and the University of Lyon.
“It’s fantastic to see this confirmation that intergalactic filaments rotate in the real Universe, as well as in computer simulation.”
By stacking thousands of cosmic filaments together and examining the velocity of galaxies perpendicular to the filament’s axis (via their redshift and blueshift), Dr. Libeskind and colleagues found that these structures display motion consistent with rotation, making them the largest objects known to have angular momentum.
“By mapping the motion of galaxies in these huge cosmic superhighways using the Sloan Digital Sky survey, we found a remarkable property of these filaments: they spin,” said Dr. Peng Wang, an astronomer at the Leibniz-Institut für Astrophysik Potsdam.
“Despite being thin cylinders hundreds of millions of light-years long, but just a few million light-years in diameter, these fantastic tendrils of matter rotate,” Dr. Libeskind added.
“On these scales the galaxies within them are themselves just specs of dust.”
“They move on helixes or corkscrew like orbits, circling around the middle of the filament while traveling along it.”
“Such a spin has never been seen before on such enormous scales, and the implication is that there must be an as yet unknown physical mechanism responsible for torquing these objects.”
P. Wang et al. Possible observational evidence for cosmic filament spin. Nat Astron, published online June 14, 2021; doi: 10.1038/s41550-021-01380-6