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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2504.09964 |
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| _version_ | 1866912325672370176 |
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| author | Xiao, Yun-Ao Zou, Hu Feng, Lu Guo, Wei-Jian Li, Niu Li, Wen-Xiong Liu, Shu-Fei Singh, Gaurav Sui, Ji-Peng Wang, Jia-Li Xue, Sui-Jian |
| author_facet | Xiao, Yun-Ao Zou, Hu Feng, Lu Guo, Wei-Jian Li, Niu Li, Wen-Xiong Liu, Shu-Fei Singh, Gaurav Sui, Ji-Peng Wang, Jia-Li Xue, Sui-Jian |
| contents | We utilize the DESI Legacy Imaging Surveys DR10 to investigate the previously undetected faint extension of the Palomar 5 stellar stream. By applying the HDBSCAN clustering algorithm, we identify stream members and successfully extend the leading arm of the stream to approximately $\mathrm{DEC} \sim -15^\circ$. Combining the fully detected stream with a suite of mock stream simulations, we conduct a detailed comparison to constrain both the intrinsic properties of the stream and the dynamical parameters of the Milky Way (MW) halo. Our analysis yields a best-fit model characterized by eight parameters: $M_{\mathrm{halo}} = 5.67\times10^{11}\ M_{\odot}$, $r_{s,\mathrm{halo}} = 28.94\ \mathrm{kpc}$, $q_z = 0.93$, $M_{\mathrm{gc}} = 4.31\times10^{3}\ M_{\odot}$, $dM_{\mathrm{gc}}/dt = 1.81\ M_{\odot}\ \mathrm{Myr}^{-1}$, $μ_α\cosδ= -2.28\ \mathrm{mas\ yr}^{-1}$, $μ_δ = -2.26\ \mathrm{mas\ yr}^{-1}$, and $D = 23.25\ \mathrm{kpc}$. Notably, our constraints on the halo shape indicate that the MW's dark matter halo exhibits a flattened potential, with a minor-to-major axis ratio of $q_z = 0.93$. This finding aligns well with theoretical expectations and previous observational estimates. Additionally, the best-fit model accurately reproduces the observed stream morphology and dynamics, providing a more precise understanding of both the evolution of the stream and the overall structure of the Galactic halo. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_09964 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Characterizing the Palomar 5 Stream: HDBSCAN Analysis and Galactic Halo Constraints Xiao, Yun-Ao Zou, Hu Feng, Lu Guo, Wei-Jian Li, Niu Li, Wen-Xiong Liu, Shu-Fei Singh, Gaurav Sui, Ji-Peng Wang, Jia-Li Xue, Sui-Jian Astrophysics of Galaxies We utilize the DESI Legacy Imaging Surveys DR10 to investigate the previously undetected faint extension of the Palomar 5 stellar stream. By applying the HDBSCAN clustering algorithm, we identify stream members and successfully extend the leading arm of the stream to approximately $\mathrm{DEC} \sim -15^\circ$. Combining the fully detected stream with a suite of mock stream simulations, we conduct a detailed comparison to constrain both the intrinsic properties of the stream and the dynamical parameters of the Milky Way (MW) halo. Our analysis yields a best-fit model characterized by eight parameters: $M_{\mathrm{halo}} = 5.67\times10^{11}\ M_{\odot}$, $r_{s,\mathrm{halo}} = 28.94\ \mathrm{kpc}$, $q_z = 0.93$, $M_{\mathrm{gc}} = 4.31\times10^{3}\ M_{\odot}$, $dM_{\mathrm{gc}}/dt = 1.81\ M_{\odot}\ \mathrm{Myr}^{-1}$, $μ_α\cosδ= -2.28\ \mathrm{mas\ yr}^{-1}$, $μ_δ = -2.26\ \mathrm{mas\ yr}^{-1}$, and $D = 23.25\ \mathrm{kpc}$. Notably, our constraints on the halo shape indicate that the MW's dark matter halo exhibits a flattened potential, with a minor-to-major axis ratio of $q_z = 0.93$. This finding aligns well with theoretical expectations and previous observational estimates. Additionally, the best-fit model accurately reproduces the observed stream morphology and dynamics, providing a more precise understanding of both the evolution of the stream and the overall structure of the Galactic halo. |
| title | Characterizing the Palomar 5 Stream: HDBSCAN Analysis and Galactic Halo Constraints |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2504.09964 |