A holistic review of a galactic interaction
A holistic review of a galactic interaction
复制标题
DOI：
10.1093/mnras/stab2398
复制
发表时间：
2020-12
影响因子：
4.8
通讯作者：
Douglas Grion Filho-Douglas-Grion Filho-2128815973;K. Johnston;E. Poggio;C. Laporte;R. Drimmel;E. D’Onghia
中科院分区：
文献类型：
--
作者：
Douglas Grion Filho-Douglas-Grion Filho-2128815973;K. Johnston;E. Poggio;C. Laporte;R. Drimmel;E. D’Onghia
我们作为银河系（MW）星系的居住者，受到人马座矮星系的轰击，提供了一个可以导致星系盘动态加热的物理过程的亲密视角。虽然这种演变是由人马座煽动的，但它也受到暗物质晕和圆盘本身交织在一起的影响。我们分析了一个N体模拟后，人马座星系与MW类主机相互作用，解开这些不同的影响，在一个小合并的阶段。在模拟中，对于每个快照计算每个分量在盘平面内的加速度，然后将其分解成环上的傅里叶级数。分析图量化和比较了空间和时间上的各个贡献的尺度：（i）由于卫星的加速度只在盘通道周围是重要的;（ii）这些通道周围的影响通过暗物质晕的扭曲而增强和扩展;（iii）相互作用驱动盘在平面内和垂直于平面的不对称性，这些扭曲的重力随着时间的推移而增加，最终导致形成条。这些结果对于识别我们银河系中的不同影响具有有趣的意义。目前，人马座足够接近一个平面交叉，以寻找其在中间半径的影响的局部签名，MW的暗物质晕的扭曲应该在外盘上留下印记，而盘自身的自洽反应正在雕刻中间和内盘。
Our situation as occupants of the Milky Way (MW) Galaxy, bombarded by the Sagittarius dwarf galaxy, provides an intimate view of physical processes that can lead to the dynamical heating of a galactic disc. While this evolution is instigated by Sagittarius, it is also driven by the intertwined influences of the dark matter halo and the disc itself. We analyse an N-body simulation following a Sagittarius-like galaxy interacting with a MW-like host to disentangle these different influences during the stages of a minor merger. The accelerations in the disc plane from each component are calculated for each snapshot in the simulation, and then decomposed into Fourier series on annuli. The analysis maps quantify and compare the scales of the individual contributions over space and through time: (i) accelerations due to the satellite are only important around disc passages; (ii) the influence around these passages is enhanced and extended by the distortion of the dark matter halo; (iii) the interaction drives disc asymmetries within and perpendicular to the plane and the self-gravity of these distortions increase in importance with time eventually leading to the formation of a bar. These results have interesting implications for identifying different influences within our own Galaxy. Currently, Sagittarius is close enough to a plane crossing to search for localized signatures of its effect at intermediate radii, the distortion of the MW’s dark matter halo should leave its imprint in the outer disc and the disc’s own self-consistent response is sculpting the intermediate and inner disc.