Cold Dust in Hot Regions
  We mapped five massive star forming regions with the SCUBA-2 camera on the
James Clerk Maxwell Telescope (JCMT). Temperature and column density maps are
obtained from the SCUBA-2 450 and 850 $\mu$m images. Most of the dense clumps
we find have central temperatures below 20 K with some as cold as 8 K,
suggesting that they have no internal heating due to the presence of embedded
protostars. This is surprising, because at the high densities inferred from
these images and at these low temperatures such clumps should be unstable,
collapsing to form stars and generating internal heating. The column densities
at the clump centres exceed 10$^{23}$ cm$^{-2}$, and the derived peak visual
extinction values are from 25-500 mag for $\beta$ = 1.5-2.5, indicating highly
opaque centres. The observed cloud gas masses range from $\sim$ 10 to 10$^{3}$
M$_{\odot}$. The outer regions of the clumps follow an $r^{-2.36\pm0.35}$
density distribution and this power-law structure is observed outside of
typically 10$^{4}$ AU. All these findings suggest that these clumps are
high-mass starless clumps and most likely contain high-mass starless cores.
