Work

Searching for signatures of self-interacting dark matter in halos from full physics simulations: From 3D structure to projected observables

Year: 2026

Type: article

Abstract: In this work we explore the imprints of self-interacting dark matter (SIDM) on the structure of simulated galaxy groups and clusters in view of future optical surveys. We find that baryonic and projection effects both lead to a significant reduction of the SIDM core-forming behavior in the mass and density profiles, resulting in very small (≲5%) deviations from the profiles of standard collisionless dark matter. The opposite trend emerged for our most massive halos, where SIDM significantly enhances the central density instead. We compared these halos with the observed dark matter profiles of two galaxy clusters, MACS J1206 and Abell S1063, finding that SIDM may leave potentially detectable imprints on cluster cores when considering the small observational uncertainty of current kinematic mass measurements. Finally, we find that weak lensing observations provide a promising tool for testing SIDM on cluster scales. In an idealized scenario where systematics are under control, weak lensing shear profiles exhibit deviations of up to ∼20% for M 200 ≳ 10 13 M ⊙ halos. Conversely, the projected concentration–mass relation is only slightly modified by our SIDM models. We discuss the limitations of our analysis and the impact of the simulation resolution as well as possible extension of this work. Overall, our results provide a baseline for future SIDM studies. Although line-of-sight projection and baryonic effects significantly reduce SIDM imprints on halo mass profiles, weak lensing and kinematic analyses in galaxy clusters may potentially allow for robust detection and constraining of dark matter self-interactions in massive structures from megaparsec down to kiloparsec scales.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202661789

Authors: G. Y. Ferron, A. Ragagnin, L. Pizzuti, M. S. Fischer

Institutions: University of Milano-Bicocca, Trieste Astronomical Observatory, National Institute for Astrophysics, Donostia International Physics Center

Language: English

Topic: Dark Matter and Cosmic Phenomena

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865

Funders: European High Performance Computing Joint Undertaking, Alexander von Humboldt-Stiftung, Dipartimenti di Eccellenza, China Scholarship Council