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arXiv 2102.05671astro-ph.GAastro-ph.CO
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z $\sim 4.5$尘埃成星星系的动力学性质及其与局域早型星系的联系

Dynamical properties of z $\sim 4.5$ dusty star-forming galaxies and their connection with local early type galaxies

Francesca Rizzo, Simona Vegetti, Filippo Fraternali, Hannah Stacey, Devon Powell

摘要:

有一个很大的共识,在高$z$星系的气体是高度动荡的,因为合并和气体吸积驱动的恒星反馈过程和引力不稳定性的组合。在本文中,我们介绍了在$4 \lesssim z\lesssim 5$的五个尘埃星形成星系(DSFG)的样本的分析。利用强引力透镜的放大能力,我们从ALMA观测到的[CII]发射线中量化了它们的运动学和动力学性质。我们结合这些星系的动力学测量与以前的研究中获得的高质量的数据和sub-kpc的空间分辨率,到目前为止,建立最大的样本$z \sim 4.5$星系。我们发现样本中的所有星系都是动态冷的,旋转与随机运动的比值$V/σ$在7到15之间。它们的速度色散和恒星形成率之间的关系表明,恒星反馈足以维持这些星系内的湍流,不需要进一步的机制。此外,我们进行了旋转曲线分解,以推断重子(气体,恒星)和暗物质成分的相对贡献的总引力势。这种分析使我们能够比较所研究的DSFG与它们的后代,当地的早期类型星系的结构特性。特别是,我们发现样本的六个星系中有五个显示出隆起的动力学特征,表明球状分量已经在$z \sim 4.5$中就位。

英文摘要:

There is a large consensus that gas in high-$z$ galaxies is highly turbulent, because of a combination of stellar feedback processes and gravitational instabilities driven by mergers and gas accretion. In this paper, we present the analysis of a sample of five Dusty Star Forming Galaxies (DSFGs) at $4 \lesssim z\lesssim 5$. Taking advantage of the magnifying power of strong gravitational lensing, we quantified their kinematic and dynamical properties from ALMA observations of their [CII] emission line. We combined the dynamical measurements obtained for these galaxies with those obtained from previous studies to build the largest sample of $z \sim 4.5$ galaxies with high-quality data and sub-kpc spatial resolutions, so far. We found that all galaxies in the sample are dynamically cold, with rotation-to-random motion ratios, $V/σ$, between 7 to 15. The relation between their velocity dispersions and their star-formation rates indicates that stellar feedback is sufficient to sustain the turbulence within these galaxies and no further mechanisms are needed. In addition, we performed a rotation curve decomposition to infer the relative contribution of the baryonic (gas, stars) and dark matter components to the total gravitational potentials. This analysis allowed us to compare the structural properties of the studied DSFGs with those of their descendants, the local early type galaxies. In particular, we found that five out of six galaxies of the sample show the dynamical signature of a bulge, indicating that the spheroidal component is already in place at $z \sim 4.5$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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