Extended HNCO, SiO, and HC$_{3}$N emission in 43 southern star-forming
  regions
  We have selected 43 southern massive star-forming regions to study the
spatial distribution of HNCO 4$_{04}$-3$_{03}$, SiO 2-1 and HC$_{3}$N 10-9 line
emission and to investigate their spatial association with the dust emission.
The morphology of HNCO 4$_{04}$-3$_{03}$ and HC$_{3}$N 10-9 agrees well with
the dust emission. HC$_{3}$N 10-9 tends to originate from more compact regions
than HNCO 4$_{04}$-3$_{03}$ and SiO 2-1. We divided our sources into three
groups: those in the Central Molecular Zone (CMZ), those associated with
bubbles (Bubble), and the remaining sources, which are termed 'normal star
forming regions' (NMSFR). These three groups, subdivided into three different
categories with respect to line widths, integrated intensities, and column
densities, hint at the presence of different physical and chemical processes.
We find that the dust temperature $T_{\rm d}$, and the abundance ratios of
$N_{\rm HNCO}/N_{\rm SiO}$ and $N_{\rm HNCO}/N_{\rm HC3N}$ show a decreasing
trend towards the central dense regions of CMZ sources, while $N_{\rm
HC3N}/N_{\rm SiO}$ moves into the opposite direction. Moreover, a better
agreement is found between $T_{\rm d}$ and $N_{\rm HC3N}/N_{\rm SiO}$ in Bubble
and NMSFR category sources. Both outflow and inflow activities have been found
in eight of the sixteen bubble and NMSFR sources. The low outflow detection
rate indicates that in these sources the SiO 2-1 line wing emission is either
below our sensitivity limit or that the bulk of the SiO emission may be
produced by the expansion of an H{\sc\,ii} region or supernova remnant, which
has pushed molecular gas away forming a shock and yielding SiO.
