Superclusters of galaxiesMax Kämmerling & Joscha

Dutli

Contents

• What are superclusters of galaxies? • Historic background • Structure and geometry • The Laniakea Supercluster

What are superclusters of galaxies?

• Groups of galaxies – contain up to 50 galaxies – 1 to 2 Mpc (3.3 x 106 to 6.6 x 106 lyrs)

NGC 3190 Galaxy Group60 Mlyrs away

What are superclusters of galaxies?

• Clusters of galaxies – contain up to a thousand galaxies – 2 to 10 Mpc (6.6 x 106 to 33 x 107 lyrs)

Galaxy Cluster MACS J0152.5-2852 4.4 Glyrs away

What are superclusters of galaxies?

• Superclusters of galaxies – contain more than 105 galaxies – 33 Mpc or more (100 x 106 lyrs)

• Estimated 10 million superclusters in the observable universe

• Traditionally defined by distribution

Laniakea Superclusterhere

Structure and Geometry: The Traditional Approach

• Not bound by gravity

• Large voids of space in superclusters

• Subdivided into galaxy clouds

Old definition for superclusters not very precise!

Historic background

• George Abell (1927-1983) • 1958: Abell Catalogue of Galaxy Clusters

Virgo Supercluster

Virgo

Laniakea Supercluster

The Laniakea Supercluster

• Laniakea: Hawaiian for immeasurable heaven

• 153 Mpc in diameter (500 x 106 lyrs)

Velocity Flow Lines

Direction of Flows

https://youtu.be/No0omeHIxwo?t=347

The Laniakea Supercluster

• New definition of superclusters: – All galaxies are flowing towards a

gravitational attractor.

• The Great Attractor – Every galaxy in Laniakea drifting towards it at

a speed of several hundred kilometers per second (peculiar velocity)

Our position in Laniakea

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