Dynamic cosmography of the local Universe: Laniakea and five more watershed superclusters

Abstract

This article delivers the dynamical cosmography of the Local Universe within z=0.1 (1 giga light-years). We exploit the gravitational velocity field computed using the CosmicFlows-4 catalog of galaxy distances to delineate superclusters as watersheds, publishing for the first time their size, shape, main streams of matter and the location of their central attractor. Laniakea, our home supercluster's size is confirmed to be 2 $\times 10^6$ (Mpc $h^{-1}$)${}^3$. Five more known superclusters are now dynamically defined in the same way: Apus, Hercules, Lepus, Perseus-Pisces and Shapley. Also, the central repellers of the Bootes and Sculptor voids are found and the Dipole and Cold Spot repellers now appear as a single gigantic entity. Interestingly the observed superclusters are an order of magnitude larger than the theoretical ones predicted by cosmological $\Lambda$CDM simulations.

8 pages, 4 figures, 1 table, accepted in A&A (AA/2023/46802)

References in corpus (13)

• The Laniakea supercluster of galaxies
• Galaxy Groups within 3500 km s${}^{-1}$
• The 6dF Galaxy Survey: Peculiar Velocity Field and Cosmography
• Galaxy Groups: A 2MASS Catalog
• Cosmicflows-4
• The Dipole Repeller
• Galaxies in voids assemble their stars slowly
• Multiscale cosmic web detachments, connectivity, and preprocessing in the supercluster SClA2142 cocoon
• Gravity in the Local Universe : density and velocity fields using CosmicFlows-4
• Cosmicflows-3: Cold Spot Repeller?
• Studying large-scale structure probes of modified gravity with COLA
• Segmenting the Universe into dynamically coherent basins
• Superclusters from velocity divergence fields

Cited by in corpus (13)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• An effective description of Laniakea: impact on cosmology and the local determination of the Hubble constant
• Identification of Basins of Attraction in the Local Universe
• Simulating the LOcal Web (SLOW) II: Properties of local galaxy clusters
• CHANCES, the Chilean Cluster Galaxy Evolution Survey: Selection and initial characterisation of clusters and superclusters
• A New Uncertainty Scheme for Galaxy Distances from Flow Models
• The multi-wavelength Tully-Fisher relation in the TNG50 cosmological simulation
• Galaxy Superclusters and Their Complexes in the Cosmic Web
• The subtle statistics of the distance ladder: On the distance prior and selection effects
• The need for a nonlocal expansion in general relativity
• Consistencies and inconsistencies in redshift-independent distances
• Effects of local cosmic inhomogeneities on the gravitational wave event rate
• Testing Weak Equivalence Principle with IceCube Event and Blazar