Candidate super star cluster progenitor gas clouds possibly triggered by
  close passage to Sgr A*
  Super star clusters are the end product of star formation under the most
extreme conditions. As such, studying how their final stellar populations are
assembled from their natal progenitor gas clouds can provide strong constraints
on star formation theories. An obvious place to look for the initial conditions
of such extreme stellar clusters are gas clouds of comparable mass and density,
with no star formation activity. We present a method to identify such
progenitor gas clouds and demonstrate the technique for the gas in the inner
few hundred pc of our Galaxy. The method highlights three clouds in the region
with similar global physical properties to the previously identified extreme
cloud, G0.253+0.016, as potential young massive cluster (YMC) precursors. The
fact that four potential YMC progenitor clouds have been identified in the
inner 100 pc of the Galaxy, but no clouds with similar properties have been
found in the whole first quadrant despite extensive observational efforts, has
implications for cluster formation/destruction rates across the Galaxy. We put
forward a scenario to explain how such dense gas clouds can arise in the
Galactic centre environment, in which YMC formation is triggered by gas streams
passing close to the minimum of the global Galactic gravitational potential at
the location of the central supermassive black hole, Sgr A*. If this triggering
mechanism can be verified, we can use the known time interval since closest
approach to Sgr A* to study the physics of stellar mass assembly in an extreme
environment as a function of absolute time.
