论文标题
银河系中央分子区域的模拟-II。星形形成
Simulations of the Milky Way's central molecular zone -- II. Star formation
论文作者
论文摘要
近年来,银河系的中央分子区(CMZ)成为恒星形成研究的独特实验室。在这里,我们使用Tress等人中提出的模拟。 2020研究CMZ中的恒星形成。这些模拟可以在亚比索分辨率下解决星际介质的结构,同时还包括嵌入CMZ的大规模流量。我们的主要发现如下。 (1)虽然大多数恒星形成发生在$ r \ gtrsim100 {\,\ rm pc} $的CMZ环中,但在$ r \ lyssim 10 {\,\ rm pc} $上也更接近sgra*。 (2)CMZ中的大多数恒星形成发生在启示中心的下游,与“弦上”场景一致,并且与pericentre通道触发的恒星形成的绝对进化时间表相反。 (3)在我们的仿真时间尺度($ \ sim100 $ myr)中,CMZ的耗竭时间在$ \ sim2 $的一倍以内。这表明,恒星形成率的变化主要是由CMZ质量的变化驱动的,例如,AGN反馈或外部诱导的条形驱动流入率变化引起的,而不是由耗竭时间的变化引起的。 (4)我们在模拟中研究了新出生的恒星的轨迹。我们发现了几个具有年龄和3D速度的示例与拱门和五胞胎簇的速度兼容。我们的模拟表明,这些突出的集群起源于碰撞地点附近,在该碰撞地点,在该碰撞地点,在那里,与银河系中心相对的位置,在该碰撞地点上积聚了cmz,并且它们已经与出生的气体脱离了。
The Milky Way's central molecular zone (CMZ) has emerged in recent years as a unique laboratory for the study of star formation. Here we use the simulations presented in Tress et al. 2020 to investigate star formation in the CMZ. These simulations resolve the structure of the interstellar medium at sub-parsec resolution while also including the large-scale flow in which the CMZ is embedded. Our main findings are as follows. (1) While most of the star formation happens in the CMZ ring at $R\gtrsim100 {\, \rm pc}$, a significant amount also occurs closer to SgrA* at $R \lesssim 10{\, \rm pc}$. (2) Most of the star formation in the CMZ happens downstream of the apocentres, consistent with the "pearls-on-a-string" scenario, and in contrast to the notion that an absolute evolutionary timeline of star formation is triggered by pericentre passage. (3) Within the timescale of our simulations ($\sim100$ Myr), the depletion time of the CMZ is constant within a factor of $\sim2$. This suggests that variations in the star formation rate are primarily driven by variations in the mass of the CMZ, caused for example by AGN feedback or externally-induced changes in the bar-driven inflow rate, and not by variations in the depletion time. (4) We study the trajectories of newly born stars in our simulations. We find several examples that have age and 3D velocity compatible with those of the Arches and Quintuplet clusters. Our simulations suggest that these prominent clusters originated near the collision sites where the bar-driven inflow accretes onto the CMZ, at symmetrical locations with respect to the Galactic centre, and that they have already decoupled from the gas in which they were born.