Laniakea Supercluster

Laniakea Supercluster
Andrew Z. Colvin · CC BY-SA 4.0 · source
Name	Laniakea Supercluster
Caption	Map of the local velocity flow defining the supercluster
Type	Supercluster
Location	Local Universe
Discovered	2014
Discoverers	Brent Tully, R. Brent Tully, Hélène Courtois, Yehuda Hoffman, Daniel Pomarède
Distance	~100 million light-years (scale varies)
Major components	Virgo Cluster, Hydra Cluster, Centaurus Cluster, Norma Cluster, Perseus–Pisces complex

Laniakea Supercluster Laniakea Supercluster is a vast gravitationally defined assembly of galaxies in the nearby Universe, encompassing the Milky Way and thousands of galaxy groups and clusters. It was delineated in 2014 using peculiar velocity flow mapping and redefined the local cosmic neighborhood by linking disparate concentrations such as the Virgo Cluster and the Hydra–Centaurus region. The concept reframes the Milky Way's location relative to large-scale features like the Shapley Concentration and the Great Attractor.

Discovery and Naming

The recognition of this structure resulted from work by astronomers associated with University of Hawaii researchers including Brent Tully and collaborators who used data and methods developed at institutions like University of Lyon and Hebrew University of Jerusalem. Initial observational programs such as the 2MASS Redshift Survey and redshift compilations from teams at Johns Hopkins University and University of California, Berkeley provided distance and velocity constraints feeding into reconstructions by groups at University of Strasbourg and Polish Academy of Sciences. The Hawaiian-derived name combines Hawaiian language tradition with astronomical naming practices akin to earlier labels like Local Group, Virgo Supercluster, and Shapley Supercluster.

Definition and Boundaries

Laniakea was defined using a velocity-flow criterion tied to the gravitational basin of attraction centered near the region of the Great Attractor and the Norma Cluster (Abell 3627). Boundaries were drawn where galaxy peculiar velocities converge toward common flow lines, using techniques employed in studies at Max Planck Institute for Astrophysics and Princeton University. This approach differs from purely density-based definitions used in catalogues from Sloan Digital Sky Survey teams or the Two-degree Field Galaxy Redshift Survey, making the supercluster a kinematic entity analogous to definitions applied by researchers at Harvard–Smithsonian Center for Astrophysics and Observatoire de Paris.

Structure and Components

The supercluster encompasses well-known concentrations such as the Virgo Cluster, Centaurus Cluster, Hydra Cluster, and links to the Perseus–Pisces Supercluster, along with less prominent groups catalogued in compilations by George Abell and surveys by Arecibo Observatory. Major filaments and walls identified by scientists at California Institute of Technology and University of Arizona thread between clusters, resembling features mapped in studies involving Hubble Space Telescope distance indicators, Spitzer Space Telescope photometry, and radio observations from National Radio Astronomy Observatory. Multiple galaxy catalogues from institutions like European Southern Observatory and Kavli Institute for Cosmology enumerate thousands of member galaxies, including the Milky Way's host, the Local Group, and nearby systems such as Messier 31 and Messier 81.

Dynamics and Kinematics

Peculiar velocity reconstructions driving the supercluster definition relied on methods developed by teams at Rutgers University and Tel Aviv University and numerical inversion techniques akin to those used in studies by Yehuda Hoffman. Flow toward the Great Attractor and motion relative to the Cosmic Microwave Background rest frame were quantified similarly to analyses coming from Wilkinson Microwave Anisotropy Probe and Planck (spacecraft) teams. Kinematic maps show coherent inflow patterns and shear across the supercluster comparable to bulk flows reported by groups at University of Oxford and University of Cambridge, with typical velocities of several hundred kilometres per second in regional basins.

Formation and Evolution

Formation scenarios draw on hierarchical clustering theory developed by researchers at Los Alamos National Laboratory and Institute for Advanced Study, using cosmological simulations from groups at Illustris and Millennium Simulation teams. Over cosmic time, small density fluctuations seeded in the era probed by Wilkinson Microwave Anisotropy Probe and Planck (spacecraft) grew via gravity into filaments and nodes identified within Laniakea, following physics studied by investigators at Lawrence Berkeley National Laboratory and Fermi National Accelerator Laboratory. Mergers of groups and accretion along filaments mirror processes observed in cluster studies by Chandra X-ray Observatory and XMM-Newton teams, shaping present-day mass distribution and intracluster medium properties catalogued by NASA and European Space Agency programs.

Relationship to Nearby Large-Scale Structures

Laniakea sits in a complex neighborhood including the Shapley Supercluster, the Sloan Great Wall, and the Hercules–Corona Borealis Great Wall at larger scales; interactions among these structures have been topics of study for researchers at University of Chicago and Columbia University. The supercluster's gravitational influence contributes to flows toward the Shapley Concentration and affects observed anisotropies measured by teams at Max Planck Institute for Astrophysics and University of Toronto. Comparative analyses reference historical frameworks such as the Catalog of Nearby Galaxies and modern reconstructions by the Cosmicflows collaboration.

Observational Evidence and Methods

Evidence for the supercluster combines galaxy redshift surveys, distance indicators like Cepheid variables, Type Ia supernovae, and surface brightness fluctuation work performed by groups at Carnegie Institution for Science and Space Telescope Science Institute. Peculiar velocities were extracted using methodologies refined by researchers at Instituto de Astrofísica de Canarias and Observatoire de Paris, while reconstruction algorithms were implemented by teams including Hélène Courtois and colleagues. Multiwavelength observations from facilities such as Subaru Telescope, Keck Observatory, and Very Large Array complement X-ray studies from Chandra X-ray Observatory, enabling mass estimates and flow mapping that underpin the kinematic boundary assignment used to delineate the supercluster.

Category:Superclusters