ARC Centre of Excellence in All Sky Astrophysics (ASTRO 3D)
via Science in Public (SIP) | 2019 Nov 15
Sky survey provides clues to how they change over time.
The direction in which a galaxy spins depends on its mass, researchers have found.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.
Credit: Tiamat simulation, Greg Poole
A team of astrophysicists analysed 1418 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 galaxy’s closest “cosmic filament” – the largest structures in the universe.
Filaments are massive thread-like formations, comprising huge amounts of matter – including galaxies, gas and, modelling implies, dark matter. They can be 500 million light years long but just 20 million light years wide. At their largest scale, the filaments divide the universe into a vast gravitationally linked lattice interspersed with enormous dark matter voids.
“It’s worth noticing that the spine of cosmic filaments is pretty much the highway of galactic migration, with many galaxies encountering and merging along the way,” says lead researcher Charlotte Welker ...
They found that smaller ones tended to rotate in direct alignment to the filaments, while larger ones turned at right angles. 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. ...
The SAMI Galaxy Survey: First Detection of a Transition in Spin Orientation
with Respect to Cosmic Filaments in the Stellar Kinematics of Galaxies ~ C. Welker et al
- Monthly Notices of the RAS (online 12 Oct 2019) DOI: 10.1093/mnras/stz2860
- arXiv.org > astro-ph > arXiv:1909.12371 > 26 Sep 2019
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