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arXiv 2103.12737astro-ph.GA
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动力学击败尘埃:揭示Milky Way扰动外盘的嵌套子结构

Kinematics beats dust: unveiling nested substructure in the perturbed outer disc of the Milky Way

Chervin F. P. Laporte, Sergey E. Koposov, Vasily Belokurov

摘要:

我们使用$Gaia$ eDR 3数据和传统的光谱调查,以绘制银河系盘子结构朝向银河系的Anticenter在日心距离$d\geq10\,\rm{kpc}$。我们报告发现了多个以前未被发现的新的细丝嵌入外盘在高度膨胀的地区。在这些密度过高的恒星有距离梯度,预计光盘材料和磁盘一样的轨道上移动与$v_ϕ\sim170-230\,\rm{km\,s^{-1}}$,显示出小的能量扩散。这种形态与静止生长的银河系薄盘相矛盾。其中一些结构被解释为受激的外盘物质,由卫星撞击产生,目前正在进行相位混合(“羽毛”)。由于外盘区域的时间尺度较长,这些结构可以在几个陀螺仪上保持位形空间的相干性。然而,我们注意到,这些结构中的一些也可能是从太阳位置投影中看到的扰动盘中的褶皱。一个完整的6D相空间特征和年龄测定这些结构应该有助于区分这两种可能的形态。

英文摘要:

We use $Gaia$ eDR3 data and legacy spectroscopic surveys to map the Milky Way disc substructure towards the Galactic Anticenter at heliocentric distances $d\geq10\,\rm{kpc}$. We report the discovery of multiple previously undetected new filaments embedded in the outer disc in highly extincted regions. Stars in these over-densities have distance gradients expected for disc material and move on disc-like orbits with $v_ϕ\sim170-230\,\rm{km\,s^{-1}}$, showing small spreads in energy. Such a morphology argues against a quiescently growing Galactic thin disc. Some of these structures are interpreted as excited outer disc material, kicked up by satellite impacts and currently undergoing phase-mixing ("feathers"). Due to the long timescale in the outer disc regions, these structures can stay coherent in configuration space over several Gyrs. We nevertheless note that some of these structures could also be folds in the perturbed disc seen in projection from the Sun's location. A full 6D phase-space characterization and age dating of these structure should help distinguish between the two possible morphologies.

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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