标题： 湍流为高压环境中的恒星形成设定了初始条件 显示英文标题

标题： Turbulence sets the initial conditions for star formation in high-pressure environments

摘要： 尽管超音速湍流等温介质的理论模型简单，但它们的预测成功地匹配了太阳邻域低压（P/k < 10^5 K cm^-3）分子云中的观测气体结构和恒星形成活动。 然而，这些理论是否适用于高压（P/k > 10^7 K cm^-3）环境中的云，例如银河系内部200 pc中心分子区（CMZ）和早期宇宙中的云，尚不清楚。 在这里，我们展示了位于CMZ高压环境中的云G0.253+0.016中的ALMA 3mm尘埃连续谱发射。 虽然其柱密度概率分布函数（PDF）的对数正态形状和离散度与太阳邻域云非常相似，但有一个重要的定量差异：其平均柱密度高1到2个数量级。 与太阳邻域云得出的PDF相比，这种相似性和差异性符合在CMZ高压环境下湍流云模型的预测。 PDF在高柱密度处显示出轻微的偏离对数正态，证实了G0.253+0.016的年轻特性。 它缺乏恒星形成，这与理论上预测的、环境依赖的体积密度恒星形成阈值一致，该阈值比太阳邻域云的高几个数量级。 我们的结果提供了首个实证证据，表明从太阳邻域获得的分子云结构当前理论理解也适用于高压环境。 因此，我们认为这些理论可能适用于理解早期宇宙中的恒星形成。 显示英文摘要

摘要： Despite the simplicity of theoretical models of supersonically turbulent, isothermal media, their predictions successfully match the observed gas structure and star formation activity within low-pressure (P/k < 10^5 K cm^-3) molecular clouds in the solar neighbourhood. However, it is unknown if these theories extend to clouds in high-pressure (P/k > 10^7 K cm^-3) environments, like those in the Galaxy's inner 200 pc Central Molecular Zone (CMZ) and in the early Universe. Here we present ALMA 3mm dust continuum emission within a cloud, G0.253+0.016, which is immersed in the high-pressure environment of the CMZ. While the log-normal shape and dispersion of its column density PDF is strikingly similar to those of solar neighbourhood clouds, there is one important quantitative difference: its mean column density is 1--2 orders of magnitude higher. Both the similarity and difference in the PDF compared to those derived from solar neighbourhood clouds match predictions of turbulent cloud models given the high-pressure environment of the CMZ. The PDF shows a small deviation from log-normal at high column densities confirming the youth of G0.253+0.016. Its lack of star formation is consistent with the theoretically predicted, environmentally dependent volume density threshold for star formation which is orders of magnitude higher than that derived for solar neighbourhood clouds. Our results provide the first empirical evidence that the current theoretical understanding of molecular cloud structure derived from the solar neighbourhood also holds in high-pressure environments. We therefore suggest that these theories may be applicable to understand star formation in the early Universe.