KFPA Examinations of Young STellar Object Natal Environments (KEYSTONE):
  Hierarchical Ammonia Structures in Galactic Giant Molecular Clouds
  We present initial results from the K-band focal plane array Examinations of
Young STellar Object Natal Environments (KEYSTONE) survey, a large project on
the 100-m Green Bank Telescope mapping ammonia emission across eleven giant
molecular clouds at distances of $0.9-3.0$ kpc (Cygnus X North, Cygnus X South,
M16, M17, MonR1, MonR2, NGC2264, NGC7538, Rosette, W3, and W48). This data
release includes the NH$_3$ (1,1) and (2,2) maps for each cloud, which are
modeled to produce maps of kinetic temperature, centroid velocity, velocity
dispersion, and ammonia column density. Median cloud kinetic temperatures range
from $11.4\pm2.2$ K in the coldest cloud (MonR1) to $23.0\pm6.5$ K in the
warmest cloud (M17). Using dendrograms on the NH$_3$ (1,1) integrated intensity
maps, we identify 856 dense gas clumps across the eleven clouds. Depending on
the cloud observed, $40-100\%$ of the clumps are aligned spatially with
filaments identified in H$_2$ column density maps derived from SED-fitting of
dust continuum emission. A virial analysis reveals that 523 of the 835 clumps
($\sim63\%$) with mass estimates are bound by gravity alone. We find no
significant difference between the virial parameter distributions for clumps
aligned with the dust-continuum filaments and those unaligned with filaments.
In some clouds, however, hubs or ridges of dense gas with unusually high mass
and low virial parameters are located within a single filament or at the
intersection of multiple filaments. These hubs and ridges tend to host water
maser emission, multiple 70$\mu$m-detected protostars, and have masses and
radii above an empirical threshold for forming massive stars.
