Self-Interacting Dark Matter, Core Collapse and the Galaxy-Galaxy Strong Lensing Discrepancy

Fuente: arXiv
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Autores principales: Dutra, Isaque, Natarajan, Priyamvada, Gilman, Daniel
Formato: Preprint
Publicado: 2024
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author Dutra, Isaque
Natarajan, Priyamvada
Gilman, Daniel
author_facet Dutra, Isaque
Natarajan, Priyamvada
Gilman, Daniel
contents Gravitational lensing by galaxy clusters has emerged as a powerful tool to probe the standard Cold Dark Matter (CDM) paradigm of structure formation in the Universe. Despite the remarkable explanatory power of CDM on large scales, tensions with observations on small scales have been reported. Recent studies find that the observational cross-section for Galaxy-Galaxy Strong Lensing (GGSL) in clusters exceeds the CDM prediction by more than an order of magnitude, and persists even after rigorous examination of various possible systematics. We investigate the impact of modifying the internal structure of cluster dark matter sub-halos on GGSL and report that altering the inner density profile, given by $r^γ$, to steeper slopes with $γ> 2.5$ can alleviate the GGSL discrepancy. Deviating from the $γ\sim 1.0$ cusps that CDM predicts, these steeper slopes could arise in models of self-interacting dark matter undergoing core collapse. Our results motivate additional study of sub-halo core collapse in dense cluster environments.
format Preprint
id arxiv_https___arxiv_org_abs_2406_17024
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Self-Interacting Dark Matter, Core Collapse and the Galaxy-Galaxy Strong Lensing Discrepancy
Dutra, Isaque
Natarajan, Priyamvada
Gilman, Daniel
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
Gravitational lensing by galaxy clusters has emerged as a powerful tool to probe the standard Cold Dark Matter (CDM) paradigm of structure formation in the Universe. Despite the remarkable explanatory power of CDM on large scales, tensions with observations on small scales have been reported. Recent studies find that the observational cross-section for Galaxy-Galaxy Strong Lensing (GGSL) in clusters exceeds the CDM prediction by more than an order of magnitude, and persists even after rigorous examination of various possible systematics. We investigate the impact of modifying the internal structure of cluster dark matter sub-halos on GGSL and report that altering the inner density profile, given by $r^γ$, to steeper slopes with $γ> 2.5$ can alleviate the GGSL discrepancy. Deviating from the $γ\sim 1.0$ cusps that CDM predicts, these steeper slopes could arise in models of self-interacting dark matter undergoing core collapse. Our results motivate additional study of sub-halo core collapse in dense cluster environments.
title Self-Interacting Dark Matter, Core Collapse and the Galaxy-Galaxy Strong Lensing Discrepancy
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2406.17024