Relating the Structure of Dark Matter Halos to Their Assembly and Environment
We use a large N -body simulation to study the relation of the structural properties of dark matter halos to their assembly history and environment. The complexity of individual halo assembly histories can be well described by a small number of principal components (PCs), which, compared to formatio...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2020-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/aba597 |
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| author | Yangyao Chen H. J. Mo Cheng Li Huiyuan Wang Xiaohu Yang Youcai Zhang Kai Wang |
| author_facet | Yangyao Chen H. J. Mo Cheng Li Huiyuan Wang Xiaohu Yang Youcai Zhang Kai Wang |
| author_sort | Yangyao Chen |
| collection | DOAJ |
| description | We use a large N -body simulation to study the relation of the structural properties of dark matter halos to their assembly history and environment. The complexity of individual halo assembly histories can be well described by a small number of principal components (PCs), which, compared to formation times, provide a more complete description of halo assembly histories and have a stronger correlation with halo structural properties. Using decision trees built with the random ensemble method, we find that about 60%, 10%, and 20% of the variances in halo concentration, axis ratio, and spin, respectively, can be explained by combining four dominating predictors: the first PC of the assembly history, halo mass, and two environment parameters. Halo concentration is dominated by halo assembly. The local environment is found to be important for the axis ratio and spin but is degenerate with halo assembly. The small percentages of the variance in the axis ratio and spin that are explained by known assembly and environmental factors suggest that the variance is produced by many nuanced factors and should be modeled as such. The relations between halo intrinsic properties and environment are weak compared to their variances, with the anisotropy of the local tidal field having the strongest correlation with halo properties. Our method of dimension reduction and regression can help simplify the characterization of the halo population and clarify the degeneracy among halo properties. |
| format | Article |
| id | doaj-art-96fef88dc18d414ba736b657174c80cc |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-96fef88dc18d414ba736b657174c80cc2025-08-20T03:41:26ZengIOP PublishingThe Astrophysical Journal1538-43572020-01-0189918110.3847/1538-4357/aba597Relating the Structure of Dark Matter Halos to Their Assembly and EnvironmentYangyao Chen0https://orcid.org/0000-0002-4597-5798H. J. Mo1https://orcid.org/0000-0001-5356-2419Cheng Li2https://orcid.org/0000-0002-8711-8970Huiyuan Wang3https://orcid.org/0000-0002-4911-6990Xiaohu Yang4https://orcid.org/0000-0003-3997-4606Youcai Zhang5https://orcid.org/0000-0003-1967-4091Kai Wang6https://orcid.org/0000-0002-3775-0484Department of Astronomy, Tsinghua University , Beijing 100084, People’s Republic of China ; yangyao-17@mails.tsinghua.edu.cn; Department of Astronomy, University of Massachusetts , Amherst, MA 01003-9305, USADepartment of Astronomy, University of Massachusetts , Amherst, MA 01003-9305, USADepartment of Astronomy, Tsinghua University , Beijing 100084, People’s Republic of China ; yangyao-17@mails.tsinghua.edu.cnKey Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China , Hefei, Anhui 230026, People’s Republic of China; School of Astronomy and Space Science, University of Science and Technology of China , Hefei, Anhui 230026, People’s Republic of ChinaDepartment of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University , Shanghai, 200240, People’s Republic of China; Tsung-Dao Lee Institute, and Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai Jiao Tong University , Shanghai, 200240, People’s Republic of ChinaKey Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030, People’s Republic of ChinaDepartment of Astronomy, Tsinghua University , Beijing 100084, People’s Republic of China ; yangyao-17@mails.tsinghua.edu.cn; Department of Astronomy, University of Massachusetts , Amherst, MA 01003-9305, USAWe use a large N -body simulation to study the relation of the structural properties of dark matter halos to their assembly history and environment. The complexity of individual halo assembly histories can be well described by a small number of principal components (PCs), which, compared to formation times, provide a more complete description of halo assembly histories and have a stronger correlation with halo structural properties. Using decision trees built with the random ensemble method, we find that about 60%, 10%, and 20% of the variances in halo concentration, axis ratio, and spin, respectively, can be explained by combining four dominating predictors: the first PC of the assembly history, halo mass, and two environment parameters. Halo concentration is dominated by halo assembly. The local environment is found to be important for the axis ratio and spin but is degenerate with halo assembly. The small percentages of the variance in the axis ratio and spin that are explained by known assembly and environmental factors suggest that the variance is produced by many nuanced factors and should be modeled as such. The relations between halo intrinsic properties and environment are weak compared to their variances, with the anisotropy of the local tidal field having the strongest correlation with halo properties. Our method of dimension reduction and regression can help simplify the characterization of the halo population and clarify the degeneracy among halo properties.https://doi.org/10.3847/1538-4357/aba597Galaxy dark matter halos |
| spellingShingle | Yangyao Chen H. J. Mo Cheng Li Huiyuan Wang Xiaohu Yang Youcai Zhang Kai Wang Relating the Structure of Dark Matter Halos to Their Assembly and Environment The Astrophysical Journal Galaxy dark matter halos |
| title | Relating the Structure of Dark Matter Halos to Their Assembly and Environment |
| title_full | Relating the Structure of Dark Matter Halos to Their Assembly and Environment |
| title_fullStr | Relating the Structure of Dark Matter Halos to Their Assembly and Environment |
| title_full_unstemmed | Relating the Structure of Dark Matter Halos to Their Assembly and Environment |
| title_short | Relating the Structure of Dark Matter Halos to Their Assembly and Environment |
| title_sort | relating the structure of dark matter halos to their assembly and environment |
| topic | Galaxy dark matter halos |
| url | https://doi.org/10.3847/1538-4357/aba597 |
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