Unexpected clustering pattern in dwarf galaxies challenges formation models

Abstract

The galaxy correlation function serves as a fundamental tool for studying cosmology, galaxy formation, and the nature of dark matter. It is well established that more massive, redder and more compact galaxies tend to have stronger clustering in space. These results can be understood in terms of galaxy formation in Cold Dark Matter (CDM) halos of different mass and assembly history. Here, we report an unexpectedly strong large-scale clustering for isolated, diffuse and blue dwarf galaxies, comparable to that seen for massive galaxy groups but much stronger than that expected from their halo mass. Our analysis indicates that the strong clustering aligns with the halo assembly bias seen in simulations with the standard $\Lambda$CDM cosmology only if more diffuse dwarfs formed in low-mass halos of older ages. This pattern is not reproduced by existing models of galaxy evolution in a $\Lambda$CDM framework, and our finding provides new clues for the search of more viable models. Our results can be explained well by assuming self-interacting dark matter, suggesting that such a scenario should be considered seriously.

Accepted for publication in Nature. 45 pages, 12 figures, 2 tables

References in corpus (20)

• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties
• Forty-Seven Milky Way-Sized, Extremely Diffuse Galaxies in the Coma Cluster
• Properties of Dark Matter Haloes in Clusters, Filaments, Sheets and Voids
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• NIHAO XI: Formation of Ultra-Diffuse Galaxies by outflows
• A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra Diffuse Galaxy Dragonfly 44
• The dependence of dark halo clustering on the formation epoch and the concentration parameter
• On Halo Formation Times and Assembly Bias
• ELUCID - Exploring the Local Universe with reConstructed Initial Density field I: Hamiltonian Markov Chain Monte Carlo Method with Particle Mesh Dynamics
• ELUCID - Exploring the Local Universe with reConstructed Initial Density field III: Constrained Simulation in the SDSS Volume
• A trail of dark matter-free galaxies from a bullet dwarf collision
• Relations Between the Sizes of Galaxies and their Dark Matter Halos at Redshifts $0<z<3$
• Ultra-diffuse galaxies without dark matter
• The Dark Matter Distributions in Low-Mass Disk Galaxies. II. The Inner Density Profiles
• A cuspy dark matter halo
• The Fate of Gas rich Satellites in Clusters
• Global dynamic scaling relations of HI-rich ultra-diffuse galaxies
• Gas-rich Ultra-diffuse Galaxies Are Originated from High Specific Angular Momentum
• VLA Imaging of HI-bearing Ultra-Diffuse Galaxies from the ALFALFA Survey