Astronomers have measured the rotation of 1,418 galaxies and found that small ones are likely to spin on a different axis to large ones. The rotation was measured in relation to each galaxys closest cosmic filament.<\/p>\n
This is a simulation showing a section of the Universe at its broadest scale; a web of cosmic filaments forms a lattice of matter, enclosing vast voids. Image credit: Greg Poole \/ Tiamat Simulation.<\/p>\n
Cosmic filaments are massive thread-like formations, comprising huge amounts of matter, including galaxies, gas and dark matter.<\/p>\n
They can be 500 million light-years long but just 20 million light-years wide.<\/p>\n
At their largest scale, they divide the Universe into a vast gravitationally linked lattice interspersed with enormous dark matter voids.<\/p>\n
The spine of cosmic filaments is pretty much the highway of galactic migration, with many galaxies encountering and merging along the way, said Dr. Charlotte Welker, a researcher at McMaster University, the ARC Centre of Excellence for Astrophysics in 3 Dimensions (ASTRO 3D) and ICRAR.<\/p>\n
Using data gathered by the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) at the Anglo-Australian Telescope, Dr. Welker and colleagues studied each of the target galaxies and measured its spin in relation to its nearest filament.<\/p>\n
They found that smaller ones tended to rotate in direct alignment to the filaments, while larger ones turned at right angles.<\/p>\n
The alignment changes from the first to the second as galaxies, drawn by gravity towards the spine of a filament, collide and merge with others, thus gaining mass.<\/p>\n
The flip can be sudden. Merging with another galaxy can be all it takes, Dr. Welker said.<\/p>\n
The result offers insight into the deep structure of the Universe, said Dr. Scott Croom, an ASTRO 3D principal investigator from the University of Sydney.<\/p>\n
Virtually all galaxies rotate, and this rotation is fundamental to how galaxies form.<\/p>\n
For example, most galaxies are in flat rotating disks, like our Milky Way. Our result is helping us to understand how that galactic rotation builds up across cosmic time.<\/p>\n
The Milky Way, by the way, has a spin well aligned with its nearest cosmic filament, but belongs to a class of intermediate size galaxies that, over all, show no clear tendency towards parallel or perpendicular spins.<\/p>\n
The findings were published in the Monthly Notices of the Royal Astronomical Society.<\/p>\n
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C. Welker et al. The SAMI Galaxy Survey: First detection of a transition in spin orientation with respect to cosmic filaments in the stellar kinematics of galaxies. MNRAS, published online October 12, 2019; doi: 10.1093\/mnras\/stz2860<\/p>\n
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Study: Direction in Which Galaxies Spin Depends on Their Mass | Astronomy - Sci-News.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" Astronomers have measured the rotation of 1,418 galaxies and found that small ones are likely to spin on a different axis to large ones. The rotation was measured in relation to each galaxys closest cosmic filament Continue reading