银河系中心势场中 circumnuclear 气体盘的旋转与稳定性研究——基于ALMA CMZ探索调查（ACES）
Rotation and stability of the circumnuclear gas disk in the Galactic Center potential by the ALMA CMZ Exploration Survey (ACES)
AI总结：
通过分析ALMA CMZ数据，研究银河系中心circumnuclear气体盘的旋转与稳定性，发现其质量分布呈尖峰型并具有自引力收缩的临界半径。
摘要：
我们通过分析来自ALMA CMZ探索调查（ACES）的分子线数据，研究了银河系中心的引力势场和质量分布。通过考察circumnuclear气体盘的形态和运动学特征，我们估计了在中心约20 pc范围内势场的形状，以重现观测到的circumnuclear气体盘（CND）的性质。通过模拟不同轴比下测试粒子的运动，我们证明势场近似为球形。我们通过应用终端速度法到位置-速度图中，构建了旋转曲线，并计算了银河系中心的质量分布。发现质量密度分布为尖峰型，近似为ρ_mass ∼ 1.56×10⁵(R/1 pc)⁻¹·⁹ M☉ pc⁻³，其中R是距离核的距离。我们讨论了由引力势场产生旋转曲线所引起的潮汐效应，并证明气体盘在临界半径R_T≈14 (ρ_gas/10⁵ H₂ cm⁻³)⁻¹/² pc内对自引力收缩是稳定的。这表明在circumnuclear区域抑制了恒星形成，并存在高质量的恒星形成效率。
英文摘要：
We investigated the gravitational potential and mass distribution in the Galactic Center by examining the morphology and kinematics of the circumnuclear gaseous disk revealed by the molecular line data from the ALMA CMZ Exploration Survey (ACES). We obtain an estimate of the shape of the potential {within the central $\sim 20$ pc} to reproduce the observed properties of the circumnuclear gas disk (CND) by simulating the motion of test particles for various axial ratios and show that the potential is approximately spherical. We construct a rotation curve by applying the terminal velocity method to the position-velocity diagrams, and calculate the mass distribution in the Galactic Center. The distribution of mass density is found to be of cusp type, approximated by $ρ_{\rm mass} \sim 1.56\times 10^5(R/1 {\rm pc})^{-1.9}~M_{\odot} {\rm pc}^{-3}$, where $R$ is the distance from the nucleus. We discuss the tidal effect caused by the gravitational potential that produces the rotation curve and show that the gas disk is stable against self-gravitational contraction within a critical radius of $ R_{\rm T}\sim 14 ~(ρ_{\rm gas}/10^5 {\rm H_2~cm^{-3}})^{-1/2}~{\rm pc}$. This suggests suppression of star formation and a top-heavy IMF in the circmunuclear region.
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