The Molecular Gas Environment in the 20 km s$^{-1}$ Cloud in the Central
  Molecular Zone
  We recently reported a population of protostellar candidates in the 20 km
s$^{-1}$ cloud in the Central Molecular Zone of the Milky Way, traced by H$_2$O
masers in gravitationally bound dense cores. In this paper, we report
high-angular-resolution ($\sim$3'') molecular line studies of the environment
of star formation in this cloud. Maps of various molecular line transitions as
well as the continuum at 1.3 mm are obtained using the Submillimeter Array.
Five NH$_3$ inversion lines and the 1.3 cm continuum are observed with the Karl
G. Jansky Very Large Array. The interferometric observations are complemented
with single-dish data. We find that the CH$_3$OH, SO, and HNCO lines, which are
usually shock tracers, are better correlated spatially with the compact dust
emission from dense cores among the detected lines. These lines also show
enhancement in intensities with respect to SiO intensities toward the compact
dust emission, suggesting the presence of slow shocks or hot cores in these
regions. We find gas temperatures of $\gtrsim$100 K at 0.1-pc scales based on
RADEX modelling of the H$_2$CO and NH$_3$ lines. Although no strong
correlations between temperatures and linewidths/H$_2$O maser luminosities are
found, in high-angular-resolution maps we notice several candidate shock heated
regions offset from any dense cores, as well as signatures of localized heating
by protostars in several dense cores. Our findings suggest that at 0.1-pc
scales in this cloud star formation and strong turbulence may together affect
the chemistry and temperature of the molecular gas.
