Journal article
The formation of cores in galaxies across cosmic time – the existence of cores is not in tension with the ΛCDM paradigm
- Abstract:
- The 'core-cusp' problem is considered a key challenge to the ΛCDM paradigm. Haloes in dark matter only simulations exhibit 'cuspy' profiles, where density continuously increases towards the centre. However, the dark matter profiles of many observed galaxies (particularly in the dwarf regime) deviate strongly from this prediction, with much flatter central regions ('cores'). We use NewHorizon (NH), a hydrodynamical cosmological simulation, to investigate core formation, using a statistically significant number of galaxies in a cosmological volume. Haloes containing galaxies in the upper (M⋆ ≥ 1010.2 M⊙) and lower (M⋆ ≤ 108 M⊙) ends of the stellar mass distribution contain cusps. However, Haloes containing galaxies with intermediate (108 M⊙ ≤ M⋆ ≤ 1010.2 M⊙) stellar masses are generally cored, with typical halo masses between 1010.2 M⊙ and 1011.5 M⊙. Cores form through supernova-driven gas removal from halo centres, which alters the central gravitational potential, inducing dark matter to migrate to larger radii. While all massive (M⋆ ≥ 109.5 M⊙) galaxies undergo a cored-phase, in some cases cores can be removed and cusps reformed. This happens if a galaxy undergoes sustained star formation at high redshift, which results in stars (which, unlike the gas, cannot be removed by baryonic feedback) dominating the central gravitational potential. After cosmic star formation peaks, the number of cores, and the mass of the Haloes they are formed in, remain constant, indicating that cores are being routinely formed over cosmic time after a threshold halo mass is reached. The existence of cores is, therefore, not in tension with the standard paradigm.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
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(Preview, Version of record, pdf, 2.0MB, Terms of use)
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- Publisher copy:
- 10.1093/mnras/stae056
Authors
- Publisher:
- Oxford University Press
- Journal:
- Monthly Notices of the Royal Astronomical Society More from this journal
- Volume:
- 528
- Issue:
- 2
- Pages:
- 1655-1667
- Publication date:
- 2024-01-11
- Acceptance date:
- 2024-01-05
- DOI:
- EISSN:
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1365-2966
- ISSN:
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0035-8711
- Language:
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English
- Keywords:
- Pubs id:
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1711762
- Local pid:
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pubs:1711762
- Deposit date:
-
2024-04-25
Terms of use
- Copyright holder:
- Jackson et al
- Copyright date:
- 2024
- Rights statement:
- © The Author(s) 2024. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
- Notes:
- For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission.
- Licence:
- CC Attribution (CC BY)
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