Probing Signals of Self-Interacting Dark Matter Core Collapse in HI-Rich Galaxies

Fuente: arXiv
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Main Authors: Kong, Demao, Yu, Hai-Bo
Format: Preprint
Published: 2025
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author Kong, Demao
Yu, Hai-Bo
author_facet Kong, Demao
Yu, Hai-Bo
contents We analyze rotation curves of five HI-rich galaxies recently discovered with MeerKAT. These galaxies exhibit sharply rising rotation curves, while their baryonic components are not dynamically dominant, suggesting that their dark matter halos have high inner densities. When fitting the standard Navarro-Frenk-White (NFW) halo model, four galaxies require extremely high halo concentrations, exceeding the cosmological median by $5σ$. In contrast, self-interacting dark matter (SIDM) halos in the core-collapse phase naturally account for the high densities in these galaxies. For halos with masses around $10^{11}~{\rm M_\odot}$, those in cosmic filaments exhibit concentrations consistent with the cosmological average, while halos in cosmic nodes show relatively higher concentrations that align with the SIDM fits but remain insufficient for the NFW fits. Our analysis indicates that these HI-rich galaxies may have formed in cosmic nodes of dark matter with significant self-interactions.
format Preprint
id arxiv_https___arxiv_org_abs_2501_06413
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probing Signals of Self-Interacting Dark Matter Core Collapse in HI-Rich Galaxies
Kong, Demao
Yu, Hai-Bo
Astrophysics of Galaxies
High Energy Physics - Phenomenology
We analyze rotation curves of five HI-rich galaxies recently discovered with MeerKAT. These galaxies exhibit sharply rising rotation curves, while their baryonic components are not dynamically dominant, suggesting that their dark matter halos have high inner densities. When fitting the standard Navarro-Frenk-White (NFW) halo model, four galaxies require extremely high halo concentrations, exceeding the cosmological median by $5σ$. In contrast, self-interacting dark matter (SIDM) halos in the core-collapse phase naturally account for the high densities in these galaxies. For halos with masses around $10^{11}~{\rm M_\odot}$, those in cosmic filaments exhibit concentrations consistent with the cosmological average, while halos in cosmic nodes show relatively higher concentrations that align with the SIDM fits but remain insufficient for the NFW fits. Our analysis indicates that these HI-rich galaxies may have formed in cosmic nodes of dark matter with significant self-interactions.
title Probing Signals of Self-Interacting Dark Matter Core Collapse in HI-Rich Galaxies
topic Astrophysics of Galaxies
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2501.06413