Herschel's view of the large-scale structure in the Chamaeleon dark
  clouds
  The Chamaeleon molecular cloud complex is one of the nearest star-forming
sites encompassing three molecular clouds with a different star-formation
history, from quiescent (Cha III) to actively forming stars (Cha II), and
reaching the end of star-formation (Cha I). To charactize its large-scale
structure, we derived column density and temperature maps using PACS and SPIRE
observations from the Herschel Gould Belt Survey, and applied several tools,
such as filament tracing, power-spectra, \Delta-variance, and probability
distribution functions of column density (PDFs), to derive physical properties.
The column density maps reveal a different morphological appearance for the
three clouds, with a ridge-like structure for Cha I, a clump-dominated regime
for Cha II, and an intricate filamentary network for Cha III. The filament
width is measured to be around 0.12\pm0.04 pc in the three clouds, and the
filaments found to be gravitationally unstable in Cha I and II, but mostly
subcritical in Cha III. Faint filaments (striations) are prominent in Cha I
showing a preferred alignment with the large-scale magnetic field. The PDFs of
all regions show a lognormal distribution at low column densities. For higher
densities, the PDF of Cha I shows a turnover indicative of an extended higher
density component, culminating with a power-law tail. Cha II shows a power-law
tail with a slope characteristic of gravity. The PDF of Cha III can be best fit
by a single lognormal. The turbulence properties of the three regions are found
to be similar, pointing towards a scenario where the clouds are impacted by
large-scale processes. The magnetic field could possibly play an important role
for the star-formation efficiency in the Chamaeleon clouds if proven that it
can effectively channel material on Cha I, and possibly Cha II, but probably
less efficiently on the quiescent Cha III cloud.
