Young stellar clusters and star formation throughout the Galaxy
  Most stars are born in rich young stellar clusters (YSCs) embedded in giant
molecular clouds. The most massive stars live out their short lives there,
profoundly influencing their natal environments by ionizing HII regions,
inflating wind-blown bubbles, and soon exploding as supernovae. Thousands of
lower-mass pre-main sequence stars accompany the massive stars, and the
expanding HII regions paradoxically trigger new star formation as they destroy
their natal clouds. While this schematic picture is established, our
understanding of the complex astrophysical processes involved in clustered star
formation have only just begun to be elucidated. The technologies are
challenging, requiring both high spatial resolution and wide fields at
wavelengths that penetrate obscuring molecular material and remove
contaminating Galactic field stars. We outline several important projects for
the coming decade: the IMFs and structures of YSCs; triggered star formation
around YSC; the fate of OB winds; the stellar populations of Infrared Dark
Clouds; the most massive star clusters in the Galaxy; tracing star formation
throughout the Galactic Disk; the Galactic Center region and YSCs in the
Magellanic Clouds. Programmatic recommendations include: developing a 30m-class
adaptive optics infrared telescope; support for high-resolution and wide field
X-ray telescopes; large-aperture sub-millimeter and far-infrared telescopes;
multi-object infrared spectrographs; and both numerical and analytical theory.
