论文标题

模拟矮人的少年星形群的结构和旋转

Structure and rotation of young massive star clusters in a simulated dwarf starburst

论文作者

Lahén, Natalia, Naab, Thorsten, Johansson, Peter H., Elmegreen, Bruce, Hu, Chia-Yu, Walch, Stefanie

论文摘要

我们在高分辨率的格里芬项目模拟中,分析了年轻明星簇种群的三维形状和运动学,并分析了金属贫困矮星级星爆的高分辨率项目模拟。遵循幂律质量分布的恒星簇是从冷ISM相形成的,在亚比索的空间分辨率下,IMF用单个恒星采样至4个太阳能。大量的恒星及其重要的反馈机制详细建模。模拟群集遵循特定角动量和质量之间的惊人紧密关系,并指示两个子群。大量簇($ m_ \ mathrm {Cl} \ gtrsim 3 \ times 10^4 m _ {\ odot})$在低椭圆时($ε\ sim 0.2 $)具有最高的特定角动量($ε\ sim 0.2 $),并在其形状和旋转之间显示对齐。较低的质量簇具有较低的特异性动量,具有较大的散射,显示出较大的伸长范围,并且通常未对齐,表明它们不是由旋转形成的。 The most massive clusters $(M \gtrsim 10^5\,M_{\odot})$ accrete gas and proto-clusters from a $ \lesssim 100\,\rm pc$ scale local galactic environment on a $t \lesssim 10\,\rm Myr$ timescale, inheriting the ambient angular momentum properties.他们的二维运动图显示在形成时有序旋转,最高$ v \ sim 8.5 \,\ rm km s^{ - 1} $,与观察到的年轻大型群集和旧的球形簇一致,它们可能会演变成。大量簇具有角动量参数$λ_r\ Lessim 0.5 $,并显示高斯 - 热线系数$ H_3 $,它们与速度反相关,表明不对称的视线速度分布是散发性形成过程的签名。

We analyze the three-dimensional shapes and kinematics of the young star cluster population forming in a high-resolution GRIFFIN project simulation of a metal-poor dwarf galaxy starburst. The star clusters, which follow a power-law mass distribution, form from the cold ISM phase with an IMF sampled with individual stars down to 4 solar masses at sub-parsec spatial resolution. Massive stars and their important feedback mechanisms are modelled in detail. The simulated clusters follow a surprisingly tight relation between the specific angular momentum and mass with indications of two sub-populations. Massive clusters ($M_\mathrm{cl}\gtrsim 3\times 10^4 M_{\odot})$ have the highest specific angular momenta at low ellipticities ($ε\sim 0.2$) and show alignment between their shapes and rotation. Lower mass clusters have lower specific angular momenta with larger scatter, show a broader range of elongations, and are typically misaligned indicating that they are not shaped by rotation. The most massive clusters $(M \gtrsim 10^5\,M_{\odot})$ accrete gas and proto-clusters from a $ \lesssim 100\,\rm pc$ scale local galactic environment on a $t \lesssim 10\,\rm Myr$ timescale, inheriting the ambient angular momentum properties. Their two-dimensional kinematic maps show ordered rotation at formation, up to $v \sim 8.5\,\rm km s^{-1}$, consistent with observed young massive clusters and old globular clusters, which they might evolve into. The massive clusters have angular momentum parameters $λ_R\lesssim 0.5$ and show Gauss-Hermite coefficients $h_3$ that are anti-correlated with the velocity, indicating asymmetric line-of-sight velocity distributions as a signature of a dissipative formation process.

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