We discuss in detail the reliability of the mass spectra derived by studying their dependence on the control parameters of the decomposition algorithm.
All clump mass spectra found are consistent with a power law,
, with 
between 1.6 and 1.8. Due
to the different resolution of the observations and the different
distances of the clouds, the clump masses range from several 
M 
in NGC 7538 down to 
M , less than the mass of
Jupiter, in the nearby cloud L1457. The large dynamic range covered
by the observations is reflected by the high number of clumps found
in each cloud, which lie between 100 and 1300. The spectral index of
the clump mass distributions thus is independent of the wide range
of physical properties of the clouds studied. In particular, there
are no indications of a turnover of the clump mass power law index
at a characteristic clump mass such as the Jeans mass, below which
the clumps become gravitationally unbound. This is particularly
emphasized by the clump properties in L1457 most of which are
clearly sub stellar and which are far from being gravitationally
bound objects (Fig 4).
Figure 4: Clump mass spectra of the eight data sets analyzed. All
spectra are fitted by a power law function . The straight lines represent the best linear fit over
the range of masses spanned by the line. The resulting indices
lie in the range 1.59 to 1.79. .
Accepted by Astronomy & Astrophysics
Preprint available at:
http://www.ph1.uni-koeln.de/~kramer/publications.html