Universal Multistream Radial Structures of Cold Dark Matter Halos
Virialized halos of cold dark matter generically exhibit multistream structures of accreted dark matter within an outermost radial caustic known as the splashback radius. By tracking the particle trajectories that accrete onto the halos in cosmological N -body simulations, we count their number of a...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/acd7ee |
| _version_ | 1797698203186888704 |
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| author | Yohsuke Enomoto Takahiro Nishimichi Atsushi Taruya |
| author_facet | Yohsuke Enomoto Takahiro Nishimichi Atsushi Taruya |
| author_sort | Yohsuke Enomoto |
| collection | DOAJ |
| description | Virialized halos of cold dark matter generically exhibit multistream structures of accreted dark matter within an outermost radial caustic known as the splashback radius. By tracking the particle trajectories that accrete onto the halos in cosmological N -body simulations, we count their number of apocenter passages ( p ) and use them to characterize the multistream structure of dark matter particles. We find that the radial density profile for each stream, classified by the number of apocenter passages, exhibits universal features and can be described by a double power-law function comprising shallow inner slopes and steep outer slopes of indices of −1 and −8, respectively. Surprisingly, these properties hold over a wide range of halo masses. The double power-law feature is persistent when dividing the sample by concentration or accretion rate. The dependence of the characteristic scale and amplitude of the profile on p cannot be replicated by known self-similar solutions, requiring consideration of complexities such as the distribution of angular momentum or mergers. |
| first_indexed | 2024-03-12T03:50:51Z |
| format | Article |
| id | doaj.art-b92145dd9c6f4a1cbcff565ff75c165d |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-12T03:50:51Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj.art-b92145dd9c6f4a1cbcff565ff75c165d2023-09-03T12:22:42ZengIOP PublishingThe Astrophysical Journal Letters2041-82052023-01-019502L1310.3847/2041-8213/acd7eeUniversal Multistream Radial Structures of Cold Dark Matter HalosYohsuke Enomoto0Takahiro Nishimichi1https://orcid.org/0000-0002-9664-0760Atsushi Taruya2https://orcid.org/0000-0002-4016-1955Department of Physics, Kyoto University Kyoto 606-8502, JapanCenter for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University , Kyoto 606-8502, Japan; Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study , The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan; Department of Astrophysics and Atmospheric Sciences, Faculty of Science, Kyoto Sangyo University , Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555, JapanCenter for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University , Kyoto 606-8502, Japan; Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study , The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, JapanVirialized halos of cold dark matter generically exhibit multistream structures of accreted dark matter within an outermost radial caustic known as the splashback radius. By tracking the particle trajectories that accrete onto the halos in cosmological N -body simulations, we count their number of apocenter passages ( p ) and use them to characterize the multistream structure of dark matter particles. We find that the radial density profile for each stream, classified by the number of apocenter passages, exhibits universal features and can be described by a double power-law function comprising shallow inner slopes and steep outer slopes of indices of −1 and −8, respectively. Surprisingly, these properties hold over a wide range of halo masses. The double power-law feature is persistent when dividing the sample by concentration or accretion rate. The dependence of the characteristic scale and amplitude of the profile on p cannot be replicated by known self-similar solutions, requiring consideration of complexities such as the distribution of angular momentum or mergers.https://doi.org/10.3847/2041-8213/acd7eeGalaxy dark matter halosLarge-scale structure of the universe |
| spellingShingle | Yohsuke Enomoto Takahiro Nishimichi Atsushi Taruya Universal Multistream Radial Structures of Cold Dark Matter Halos The Astrophysical Journal Letters Galaxy dark matter halos Large-scale structure of the universe |
| title | Universal Multistream Radial Structures of Cold Dark Matter Halos |
| title_full | Universal Multistream Radial Structures of Cold Dark Matter Halos |
| title_fullStr | Universal Multistream Radial Structures of Cold Dark Matter Halos |
| title_full_unstemmed | Universal Multistream Radial Structures of Cold Dark Matter Halos |
| title_short | Universal Multistream Radial Structures of Cold Dark Matter Halos |
| title_sort | universal multistream radial structures of cold dark matter halos |
| topic | Galaxy dark matter halos Large-scale structure of the universe |
| url | https://doi.org/10.3847/2041-8213/acd7ee |
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