The thin, extended planes of satellite galaxies detected around both the Milky Way and Andromeda are not a natural prediction of the LCDM paradigm. Galaxies in these distinct planes may have formed and evolved in a different way (e.g., tidally) to their off-plane neighbours. If this were the case, one would expect the on- and off-plane dwarf galaxies in Andromeda to have experienced different evolutionary histories, which should be reflected by the chemistries, dynamics, and star formation histories of the two populations. In this work, we present new, robust kinematic observations for 2 on-plane M31 dSphs (And XVI and XVII) and compile and compare all available observational metrics for the on- and off-plane dwarfs to search for a signal that would corroborate such a hypothesis. We find that, barring their spatial alignment, the on- and off-plane Andromeda dwarf galaxies are indistinguishable from one another, arguing against vastly different formative and evolutionary histories for these two populations.

翻译：在银河系和安卓美达周围探测到的卫星星系的细长、延伸的平面并不是对LCDM范式的自然预测,这些不同的平面上的星系可能以不同的方式(如潮汐)形成并进化到它们的飞机外邻邦。如果是这样的话,人们会期望安卓美达的机上和机外矮星系经历不同的进化史,这应该通过这两组人口的化学、动态和恒星形成史来反映出来。在这项工作中,我们为M31dSphs(十六和十七)上的2个平面上提出了新的、强有力的运动观测,并汇编和比较了所有现有的对机上和机外侏儒的观测指标,以寻找能够证实这种假设的信号。我们发现,不考虑它们的空间一致性,安卓美达星系的上和机外矮星系相互不易分辨,因此,我们反对这两个人群的形成和进化历史存在巨大的差异。