We present submillimeter continuum maps at 450 \mu m and 850 \mu m of a 12′ \times 8′ region of the NGC 7538 high-mass star-forming region , made using the Submillimeter Common-User Bolometer Array ( SCUBA ) on the James Clerk Maxwell Telescope .
We used an automated clump-finding algorithm to identify 67 clumps in the 450 \mu m image and 77 in the 850 \mu m image .
Contrary to previous studies , we find a positive correlation between high spectral index , \alpha , and high submillimeter flux , with the difference being accounted for by different treatments of the error beam .
We interpret the higher spectral index at submillimeter peaks as a reflection of elevated dust temperature , particularly when there is an embedded infrared source , though it may also reflect changing dust properties .
The clump mass-radius relationship is well-fit by a power law of the form M \propto R ^ { - x } with x = 1.5–2.1 , consistent with theories of turbulently-supported clumps .
According to our most reliable analysis , the high-mass end ( \sim 100–2700 M _ { \odot } ) of the submillimeter clump mass function in NGC 7538 follows a Salpeter-like power law with index 2.0 \pm 0.3 .
This result agrees well with similar studies of lower-mass regions \rho Oph and Orion B .
We interpret the apparent invariance of the shape of the clump mass function over a broad range of parent cloud masses as evidence for the self-similarity of the physical processes which determine it .
This result is consistent with models which suggest that turbulent fragmentation , acting at early times , is sufficient to set the clump mass function .