The inner workings of early-type galaxies: the relation between nuclear star clusters, cores, and supermassive black holes

近年来，对星系核心和核性质的研究取得了巨大进展。星系的动力学中心被发现能够容纳两个看似不同的物体：超大质量黑洞（SBH）和紧凑的核星星团（NSC）。与先前的信念截然不同的是，人们发现这两种结构都很常见：缺乏SBH和/或NSC的星系是例外，而不是常态。此外，SBH和NSC之间的联系比人们预期的要深：两者都通过相似的标度关系与全球星系性质联系在一起;两者都包含相同的分数，约0.3%，总星系质量。

Recent years have seen dramatic progress in the study of the core and nuclear properties of galaxies. The dynamical centers of galaxies have been found capable of hosting two seemingly disparate objects: supermassive black holes (SBHs) and compact nuclear star clusters (NSCs). In a drastic departure from previous beliefs, it has been discovered that both structures are common: galaxies lacking SBHs and/or NSCs are the exception, rather than the norm. Furthermore, the connection between SBHs and NSCs is deeper than one might have expected: both are linked to the global galactic properties by similar scaling relations; both contain the same fraction, ~0.3%, of the total galactic mass.