论文标题
射手座矮人对银河系星形成历史的反复影响
The recurrent impact of the Sagittarius dwarf on the Milky Way star formation history
论文作者
论文摘要
旋转圆盘星系的卫星可以诱导相位空间特征，例如圆盘中的螺旋，垂直加热和相结合。在我们自己的银河系中也观察到了此类功能，但是由于Gaia DR2数据，银河系光盘的复杂性直到最近才完全映射。这种复杂的行为主要归因于沿其轨道的射手座矮星银河（SGR）引起的重复扰动，指出该卫星是银河系圆盘的主要动力架构。在这里，我们对Gaia DR2进行了建模，观察到颜色刻度图，以获取围绕太阳周围的〜2 kpc气泡的第一个详细的星形形成历史。它揭示了增强恒星形成的三个显着和狭窄的发作，我们可以准确地记录到发生的5.7、1.9和1 Gyr。有趣的是，这些情节的时机与根据i）轨道模拟的拟议的SGR Percentre通道一致，ii）银河盘中的相位空间特征，以及iii）SGR恒星含量。这些发现很可能表明，SGR也是银河系圆盘出色质量的重要演员，其扰动反复触发了恒星形成的主要事件。
Satellites orbiting disc galaxies can induce phase space features such as spirality, vertical heating and phase-mixing in their discs. Such features have also been observed in our own Galaxy, but the complexity of the Milky Way disc has only recently been fully mapped thanks to Gaia DR2 data. This complex behaviour is mainly ascribed to repeated perturbations induced by the Sagittarius dwarf galaxy (Sgr) along its orbit, pointing to this satellite as the main dynamical architect of the Milky Way disc. Here, we model Gaia DR2 observed colour-magnitude diagrams to obtain the first detailed star formation history of the ~ 2-kpc bubble around the Sun. It reveals three conspicuous and narrow episodes of enhanced star formation that we can precisely date as having occurred 5.7, 1.9 and 1 Gyr ago. Interestingly, the timing of these episodes coincides with proposed Sgr pericentre passages according to i) orbit simulations, ii) phase space features in the Galactic disc, and iii) Sgr stellar content. These findings most likely suggest that Sgr has also been an important actor in the build-up of the Milky Way disc stellar mass, with its perturbations repeatedly triggering major episodes of star formation.
