Self-Interacting Dark Matter and Small-Scale Gravitational Lenses in Galaxy Clusters

2021/02/28 by Daneng Yang, Hai-Bo Yu
Physics and Astronomy · #Astronomy #Astrophysics #Cluster (spacecraft) #Cold dark matter #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Dwarf galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy formation and evolution #Gravitation #Gravitational lens #Physics #Redshift #Strong gravitational lensing #Substructure #Weak gravitational lensing #astro-ph.CO #astro-ph.GA #hep-ph

paper · pdf · doi:10.1103/physrevd.104.103031

7 pages, 3 figures; minor updates on text, published version

openalex publication_date 2021/11/29 · openalex created_date 2021/12/06 · arxiv created 2022/02/23 · arxiv updated 2022/03/02 · openalex updated_date 2026/08/05

Abstract

Recently, Meneghetti et al. reported an excess of small-scale gravitational lenses in galaxy clusters. We study its implications for self-interacting dark matter (SIDM), compared with standard cold dark matter (CDM). We design controlled N-body simulations that incorporate observational constraints. The presence of early-type galaxies in cluster substructures can deepen gravitational potential and reduce tidal mass loss. Both scenarios require a relatively high baryon concentration in the substructure to accommodate the lensing measurements, and their tangential caustics are similar. The SIDM substructure can experience gravothermal collapse and produce a steeper density profile than its CDM counterpart, leading to a larger radial galaxy-galaxy strong lensing cross section, although this effect is hard to observe. Our results indicate SIDM can provide a unified explanation to small-scale lenses in galaxy clusters and stellar motions in dwarf galaxies.

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