Dana, and other "supermassive" young cluster people,
Here is a very recent, comprehensive, and very long (80 pages!!) review paper about "Young Massive Clusters"/"Massive Compact Clusters"/"Super Star Clusters"/"Young Globular Clusters"
This paper is the following preprint: arXiv:1002.1961
This paper was also published, in its final form, in the Annual Review of Astronomy and Astrophysics:
Zwart et al., 2010, ARAA,
48, 431 (But the final version could cost you money!)
http://arxiv.org/abs/1002.1961
Have you got enough data yet, my fellow Star Cluster aficionados?
I hope this paper gives you a pleasant case of "data overload"!
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And here is
even more and more data......
http://iopscience.iop.org/1538-3881/140/1/75/fulltext
which is a recent study of the very-rich system of newly-formed Very Massive star clusters belonging to the "two galaxies collision" system NGC 4038/9
These authors find that the most massive of the newly-formed young clusters are well in excess of a million solar masses per each cluster; it is hard to avoid the conclusion that some of the most massive of the new clusters which were formed in this galaxy-collision will eventually turn into "old" globular clusters. (The most luminous of these newly-formed clusters are about absolute V magnitude -15)
Here is the beginning of this paper, formatted as a Word 2000 Format (.doc) document:
Whitmore et al 2010 paper on N4039-9.doc