Molecular line mapping of the giant molecular cloud associated with RCW
  106 - IV. Ammonia towards dust emission
  Here we report observations of the two lowest inversion transitions of
ammonia with the 70-m Tidbinbilla radio telescope. They were conducted to
determine the kinetic temperatures in the dense clumps of the G333 giant
molecular cloud associated with RCW 106 and to examine the effect that accurate
temperatures have on the calculation of derived quantities such as mass. This
project is part of a larger investigation to understand the timescales and
evolutionary sequence associated with high-mass star formation, particularly
its earliest stages. Assuming that the initial chemical composition of a giant
molecular cloud is uniform, any abundance variations within will be due to
evolutionary state.
  We have identified 63 clumps using SIMBA 1.2-mm dust continuum maps and have
calculated gas temperatures for most (78 per cent) of these dense clumps. After
using Spitzer GLIMPSE 8.0 $\mu$m emission to separate the sample into IR-bright
and IR-faint clumps, we use statistical tests to examine whether our
classification shows different populations in terms of mass and temperature. We
find that clump mass and column density show no significant population
difference, and that kinetic temperature is the best parameter to distinguish
between the gravitationally bound state of each clump. The kinetic temperature
was the only parameter found to have a significantly low probability of being
drawn from the same population. This suggests that clump radii does not have a
large effect on the temperature of a clump, so clumps of similar radii may have
different internal heating mechanisms. We also find that while the IR-bright
clumps have a higher median virial mass, both samples have a similar range for
both virial mass and FWHM. There are 87 per cent (40 of 46) of the clumps with
masses larger than the virial mass, suggesting that they will form stars or are
already undergoing star formation.
