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RISN are radio-infared supernebulae excited by young, deeply embedded star
clusters. They are to Extragalactic Super Star Clusters as Ultra-compact
HII regions are to Galactic OB stars, and, like UC HII regions, their
internal kinematics
are puzzling. The typical motion of ionized gas in RISN are too fast for
sound, too slow for stellar winds, and inconsistent with their deduced
lifetimes. We have measured the ionized gas in the RISN of several
well-known starburst galaxies with effective resolution*--including thermal
broadening--*of ~5 km/sec and can for the first time see their gas motions
in detail. These sources must be observed via metal lines--hydrogen lines
are too broad. We find many sources are undergoing bulk outflows, probably
pressure driven. These could be analogous to the 'champagne flow' model,
but for giant clusters instead of individual stars, and may explain RISN
lifetimes. Other remarkable kinematic features, including sub-clusters,
can be detected with these heavy metal lines. We argue that high spectral
resolution is worth the extra observational effort.
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