From Star Clusters to Dwarf Galaxies and Galactic Nuclei

强烈的恒星形成爆发通常会产生大质量(超级)星团(SSCs)。在特别强烈的情况下，SSC被分组为星团或恒星超星系团，在一个仅跨越数百台PC的区域内包含从几十到数百个SSC。这种强烈的恒星形成事件可能在早期星系组装期间是典型的，当时富含气体的晚期类型的原始星系大量相互作用。超星系团的动力学演化最初由组成星系团的SSCs的形成机制主导，随后在几个超星系团的交叉时间内SSCs的连续合并。由此产生的物体成为卫星，可能是(1)被逐出宿主星系形成孤立的矮小星系，(2)围绕宿主形成低质量卫星，(3)继续在宿主盘内运行，或(4)向形成核的宿主中心坠落。上述可能性(I)和(Ii)是令人兴奋的，因为(A)最近有人提出，一些矮小不规则星系可能与潮汐矮星系有关，潮汐矮星系被观测到形成于相互作用星系的潮汐尾部，并包含SSC组合，以及(B)在Fornax星系团中最近发现了一类新的星系，即超致密矮星系(UCDs)。最近在两个透镜状星系的盘中发现了一类新的星团，即微弱的模糊星团(FF)，可能性很高(III)，这可能也与围绕银河系盘内运行的神秘球状星团wen有关。认识到许多晚类型的盘状星系具有由相对年轻的星团组成的核心，这使得可能性(IV)非常有趣。

Intense star formation bursts typically produce massive (super) star clusters (SSCs). In especially intense instances, the SSCs are grouped into clumps, or stellar superclusters, containing from a few-dozen to a few-hundred SSCs within a region spanning only a few hundred pc. Such intense star-formation events may have been typical during early galaxy assembly when gas-rich late-type proto-galaxies interactes profusely. The dynamical evolution of superclusters is dominated initially by the formation mechanism of the constituent SSCs, followed by the successive merging of the SSCs within a few supercluster crossing times. The resulting objects become satellites that may either (i) be expelled from the host galaxy forming isolated dwarf galaxies, (ii) orbit about the host forming low-mass satellites, (iii) continue to orbit within the disk of the host or (iv) fall towards the centre of the host forming a nucleus. The above possibilities (i) & (ii) are exciting in view of (a) recent suggestions that some dwarf irregular galaxies may be related to tidal dwarf galaxies which are observed to form in the tidal tails of interacting galaxies and contain assemblages of SSCs, and (b) the very recent finding of a new class of galaxy, namely the ultra-compact dwarf galaxies (UCDs), in the Fornax galaxy cluster. The very recent detection of a new class of star clusters, the faint fuzzies (FFs), in the disks of two lenticular galaxies is highly for possibility (iii), which is probably also relevant for the enigmatic w Cen globular cluster that orbits within the disk of the Milky Way. The realisation that many late-type disk galaxies have nuclei consisting of relatively young star clusters makes possibility (iv) highly interesting.