The Age-velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars
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arXiv
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| Format: | Preprint |
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2024
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| author | Sun, Weixiang Shen, Han Jiang, Biwei Liu, Xiaowei |
| author_facet | Sun, Weixiang Shen, Han Jiang, Biwei Liu, Xiaowei |
| contents | Using nearly 230,000 red clump (RC) stars selected from LAMOST and Gaia, we conduct a comprehensive analysis of the stellar age-velocity dispersion relations (AVRs) for various disk populations, within 5.0 $\leq$ $R$ $\leq$ 15.0 kpc and $|Z|$ $\leq$ 3.0 kpc. The AVRs of the whole RC sample stars are accurately described as $σ_{v}$ = $σ_{v,0}$ ($τ$ + 0.1)$^{β_{v}}$, with $β_{R}$, $β_ϕ$ and $β_{Z}$ displaying a global exponential decreasing trend with $R$, which may point to the difference in spatial distributions of various disk heating mechanisms. The measurements of $β$ $-$ $R$ for various disks suggest that the thin disk exhibits a radial dependence, with a global exponential decreasing trend in $β_{R}$ $-$ $R$ and $β_{Z}$ $-$ $R$, while $β_ϕ$ remains a nearly constant value (around 0.20$\sim$0.25) within 8.5 $\leq$ $R$ $\leq$ 11.5 kpc. The thick disk displays a global increasing trend in $β_{R}$ $-$ $R$, $β_ϕ$ $-$ $R$ and $β_{Z}$ $-$ $R$. These results indicate that the thin disk stars are likely heated by long-term heating from GMCs and spiral arms, while thick disk stars are likely heated by some violent heating process from merger and accretion, and/or formed by the inside-out and upside-down star formation scenarios, and/or born in the chaotic mergers of gas-rich systems and/or turbulent ISM. Our results also suggest that the disk perturbation by a recent minor merger from Sagittarius may have occurred within 3.0 Gyr. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_07089 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | The Age-velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars Sun, Weixiang Shen, Han Jiang, Biwei Liu, Xiaowei Astrophysics of Galaxies Using nearly 230,000 red clump (RC) stars selected from LAMOST and Gaia, we conduct a comprehensive analysis of the stellar age-velocity dispersion relations (AVRs) for various disk populations, within 5.0 $\leq$ $R$ $\leq$ 15.0 kpc and $|Z|$ $\leq$ 3.0 kpc. The AVRs of the whole RC sample stars are accurately described as $σ_{v}$ = $σ_{v,0}$ ($τ$ + 0.1)$^{β_{v}}$, with $β_{R}$, $β_ϕ$ and $β_{Z}$ displaying a global exponential decreasing trend with $R$, which may point to the difference in spatial distributions of various disk heating mechanisms. The measurements of $β$ $-$ $R$ for various disks suggest that the thin disk exhibits a radial dependence, with a global exponential decreasing trend in $β_{R}$ $-$ $R$ and $β_{Z}$ $-$ $R$, while $β_ϕ$ remains a nearly constant value (around 0.20$\sim$0.25) within 8.5 $\leq$ $R$ $\leq$ 11.5 kpc. The thick disk displays a global increasing trend in $β_{R}$ $-$ $R$, $β_ϕ$ $-$ $R$ and $β_{Z}$ $-$ $R$. These results indicate that the thin disk stars are likely heated by long-term heating from GMCs and spiral arms, while thick disk stars are likely heated by some violent heating process from merger and accretion, and/or formed by the inside-out and upside-down star formation scenarios, and/or born in the chaotic mergers of gas-rich systems and/or turbulent ISM. Our results also suggest that the disk perturbation by a recent minor merger from Sagittarius may have occurred within 3.0 Gyr. |
| title | The Age-velocity Dispersion Relations of the Galactic Disk as Revealed by the LAMOST-Gaia Red Clump Stars |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2412.07089 |