Universal Dark-matter Density Profiles of Cosmic Filaments
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arXiv
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| Autores principales: | , , , , , , , |
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| Formato: | Preprint |
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2026
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| _version_ | 1866910107229487104 |
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| author | Xu, Peng Jiang, Fangzhou Hasan, Farhanul Woo, Joanna Hellinger, Douglas Primack, Joel R. Faber, Sandra M. Koo, David |
| author_facet | Xu, Peng Jiang, Fangzhou Hasan, Farhanul Woo, Joanna Hellinger, Douglas Primack, Joel R. Faber, Sandra M. Koo, David |
| contents | We present a comprehensive analysis of the radial dark-matter (DM) density profiles of cosmic filaments in the hydrodynamical simulation TNG50. The cosmic web is extracted from high-resolution density grids at redshifts $z =$ 0, 0.5, 1, 2 and 3 using the DisPerSE algorithm. We show that the filament spine locations returned directly by DisPerSE do not accurately reflect the true density ridges. To address this issue, we introduce a "shrinking-cylinder" re-centering algorithm, which significantly increases the inferred central densities and restores the inner power-law behavior of the profiles. When the radial coordinate is scaled by the virial radii of the terminal nodes, the filament density profiles exhibit a nearly universal form that depends only weakly on redshift, node mass, and filament length. This result suggests that cosmic filaments, much like dark-matter halos, obey a form of structural self-similarity once an appropriate characteristic scale is introduced. By repeating the measurement using only smoothly distributed, unbound DM particles, we find that the apparent central cusp of the full profile is primarily produced by low-mass halos embedded along the filament spines, while the smooth component develops a flat core within $R/R_{\rm vir}\lesssim0.1$. The redshift evolution of this smooth component further suggests a transition from predominantly smooth filamentary accretion at high redshift to increasingly clumpy accretion at late times. Finally, we show that the universal filament profile is accurately described by a generalized triple-power-law model. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_05033 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Universal Dark-matter Density Profiles of Cosmic Filaments Xu, Peng Jiang, Fangzhou Hasan, Farhanul Woo, Joanna Hellinger, Douglas Primack, Joel R. Faber, Sandra M. Koo, David Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies We present a comprehensive analysis of the radial dark-matter (DM) density profiles of cosmic filaments in the hydrodynamical simulation TNG50. The cosmic web is extracted from high-resolution density grids at redshifts $z =$ 0, 0.5, 1, 2 and 3 using the DisPerSE algorithm. We show that the filament spine locations returned directly by DisPerSE do not accurately reflect the true density ridges. To address this issue, we introduce a "shrinking-cylinder" re-centering algorithm, which significantly increases the inferred central densities and restores the inner power-law behavior of the profiles. When the radial coordinate is scaled by the virial radii of the terminal nodes, the filament density profiles exhibit a nearly universal form that depends only weakly on redshift, node mass, and filament length. This result suggests that cosmic filaments, much like dark-matter halos, obey a form of structural self-similarity once an appropriate characteristic scale is introduced. By repeating the measurement using only smoothly distributed, unbound DM particles, we find that the apparent central cusp of the full profile is primarily produced by low-mass halos embedded along the filament spines, while the smooth component develops a flat core within $R/R_{\rm vir}\lesssim0.1$. The redshift evolution of this smooth component further suggests a transition from predominantly smooth filamentary accretion at high redshift to increasingly clumpy accretion at late times. Finally, we show that the universal filament profile is accurately described by a generalized triple-power-law model. |
| title | Universal Dark-matter Density Profiles of Cosmic Filaments |
| topic | Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2604.05033 |