Dark matter haloes from dwarf to massive galaxies: no systematic inner-density tension with ΛCDM hydrodynamical simulations
Abstract
Two of the most prominent small-scale challenges to the cold dark matter (CDM) paradigm are the cusp-core and diversity-of-rotation-curves problems. The former concerns the shallow inner DM density profiles inferred for many galaxies compared with the cusps predicted by collisionless CDM, while the latter concerns the wider range of inner DM densities and rotation curve shapes inferred observationally than hydrodynamical simulations traditionally reproduce. Robust observational constraints on DM core sizes and halo densities are therefore essential for testing both the nature of DM and the impact of galaxy formation processes. We analyse the inner DM distribution of a curated sample of 48 gas-rich galaxies and 8 Milky Way gas-poor satellites, spanning 6 orders of magnitude in M∗. We find substantial scatter in DM core sizes and degrees of coreness, with both cuspy and cored haloes occurring over a broad M∗ range. The cores are energetically consistent with stellar feedback, requiring modest supernova energy coupling efficiencies of order 0.1−1%. Comparisons with the NIHAO, FIRE-2, and EDGE simulations reveal broad agreement in the inner DM densities and logarithmic slopes of observed and simulated galaxies. The main residual differences concern the steep slopes of some massive simulated galaxies and differences in SHMRs. Using a rotation-curve diversity diagnostic from previous work, we find that extreme discrepancies with simulations are absent from our curated sample and largely attributable to uncertain kinematics or baryonic mass distributions. Within the scope of our analysis, we find no evidence of a systematic inner-density tension between our galaxy sample and current ΛCDM hydrodynamical simulations. Together with the modest energetic requirements for core formation, this substantially alleviates the cusp-core and diversity-of-rotation-curves problems.
Versions
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BibTeX
@misc{pina2026dark,
title = {{Dark matter haloes from dwarf to massive galaxies: no systematic inner-density tension with ΛCDM hydrodynamical simulations}},
author = {Pavel E. Mancera Piña and Justin I. Read and Jorge Sarrato-Alós and Claudia Muni},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.25220},
eprint = {2609.25220},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25220},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Dark matter haloes from dwarf to massive galaxies: no systematic inner-density tension with ΛCDM hydrodynamical simulations
AU - Pavel E. Mancera Piña
AU - Justin I. Read
AU - Jorge Sarrato-Alós
AU - Claudia Muni
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2609.25220
UR - https://arxiv.org/abs/2609.25220
AB - Two of the most prominent small-scale challenges to the cold dark matter (CDM) paradigm are the cusp-core and diversity-of-rotation-curves problems. The former concerns the shallow inner DM density profiles inferred for many galaxies compared with the cusps predicted by collisionless CDM, while the latter concerns the wider range of inner DM densities and rotation curve shapes inferred observationally than hydrodynamical simulations traditionally reproduce. Robust observational constraints on DM core sizes and halo densities are therefore essential for testing both the nature of DM and the impact of galaxy formation processes. We analyse the inner DM distribution of a curated sample of 48 gas-rich galaxies and 8 Milky Way gas-poor satellites, spanning 6 orders of magnitude in M_∗. We find substantial scatter in DM core sizes and degrees of coreness, with both cuspy and cored haloes occurring over a broad M_∗ range. The cores are energetically consistent with stellar feedback, requiring modest supernova energy coupling efficiencies of order 0.1−1%. Comparisons with the NIHAO, FIRE-2, and EDGE simulations reveal broad agreement in the inner DM densities and logarithmic slopes of observed and simulated galaxies. The main residual differences concern the steep slopes of some massive simulated galaxies and differences in SHMRs. Using a rotation-curve diversity diagnostic from previous work, we find that extreme discrepancies with simulations are absent from our curated sample and largely attributable to uncertain kinematics or baryonic mass distributions. Within the scope of our analysis, we find no evidence of a systematic inner-density tension between our galaxy sample and current ΛCDM hydrodynamical simulations. Together with the modest energetic requirements for core formation, this substantially alleviates the cusp-core and diversity-of-rotation-curves problems.
ER -