Reconciling the Diversity and Uniformity of Galactic Rotation Curves with Self-Interacting Dark Matter

• Published in: Physical review. X Vol. 9; no. 3; p. 031020
• Main Authors: Ren, Tao, Kwa, Anna, Kaplinghat, Manoj, Yu, Hai-Bo
• Format: Journal Article
• Language: English
• Published: College Park American Physical Society 07.08.2019; American Physical Society (APS)
• Subjects: Astronomical models; Celestial bodies; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Cold dark matter; Cosmology; Dark matter; Galactic halos; Galactic rotation; Large scale structure of the universe; Phenomenology; Physicists; Physics; Rotating matter; Spiral galaxies; Stars; Stars & galaxies; Stellar mass; Structural hierarchy
• ISSN: 2160-3308; 2160-3308
• DOI: 10.1103/PhysRevX.9.031020

Galactic rotation curves exhibit diverse behavior in the inner regions while obeying an organizing principle; i.e., they can be approximately described by a radial acceleration relation or the modified Newtonian dynamics phenomenology. We analyze the rotation curve data from the SPARC sample and explicitly demonstrate that both the diversity and uniformity are naturally reproduced in a hierarchical structure formation model with the addition of dark matter self-interactions. The required concentrations of the dark matter halos are fully consistent with the concentration-mass relation predicted by the Planck cosmological model. The inferred stellar mass-to-light (3.6μm) ratios scatter around0.5M⊙/L⊙, as expected from population synthesis models, leading to a tight radial acceleration relation and a baryonic Tully-Fisher relation. The inferred stellar-halo mass relation is consistent with the expectations from abundance matching. These results provide compelling arguments in favor of the idea that the inner halos of galaxies are thermalized due to dark matter self-interactions.