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The Laniakea supercluster of galaxies
R Brent Tully1, Hélène Courtois2, Yehuda Hoffman3
1Institute for Astronomy, University of Hawaii, Honolulu, Hawaii 96822, USA.
Nature
|September 5, 2014
Summary
Astronomers mapped galaxy peculiar velocities to define cosmic structures. They identified a new supercluster, Laniakea, based on divergent galaxy flows, revealing our home in the cosmic web.
Area of Science:
- Cosmology
- Astrophysics
- Galaxy Formation and Evolution
Background:
- Galaxies are organized into clusters, filaments, and voids, forming a large-scale cosmic web.
- Existing supercluster definitions lack precision and clear boundaries.
- Peculiar velocity, the deviation from cosmic expansion due to gravity, offers a new way to map matter distribution.
Purpose of the Study:
- To create a map of cosmic structure using peculiar velocities.
- To identify and define superclusters based on gravitational flow patterns.
- To delineate the boundaries of our home supercluster.
Main Methods:
- Utilized a catalogue of peculiar velocities derived from measured galaxy distances and velocities.
- Analyzed peculiar velocity fields to find points of divergence, analogous to watershed divides.
- Defined superclusters as volumes enclosed by surfaces of divergent peculiar velocity flows.
Main Results:
- Generated a novel map of cosmic structure based on peculiar velocities.
- Identified surfaces of divergent peculiar velocity flows surrounding our local region.
- Defined the extent of our home supercluster, named Laniakea, based on these divergent flows.
Conclusions:
- Peculiar velocity mapping provides a precise method for defining large-scale structures like superclusters.
- The identified Laniakea supercluster encompasses a significant volume of the local universe.
- This new definition of superclusters offers a clearer understanding of our place within the cosmic web.
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