We present a new analysis of the properties of star-forming cores in the Perseus molecular cloud , identified in SCUBA 850 µm data originally presented by Hatchell et al .
( 26 ) .
Our goal is to determine which core properties can be robustly identified and which depend on the extraction technique .
Four regions in the cloud are examined : NGC 1333 , IC348/HH211 , L1448 and L1455 .
We identify clumps of dust emission using two popular automated algorithms , clfind and gaussclumps , finding 85 and 122 clumps in total respectively .
Using the catalogues of Hatchell et al .
( 25 ) , we separate these clumps into starless , Class 0 and Class I cores .
Some trends are true for both populations : clumps become increasingly elongated over time ; clumps are consistent with constant surface brightness objects ( i.e . M \propto R ^ { 2 } ) , with an average brightness \approx 4 –10 times larger than the surrounding molecular cloud ; the clump mass distribution ( CMD ) resembles the stellar intial mass function , with a slope \alpha = -2.0 \pm 0.1 for clfind and \alpha = -3.15 \pm 0.08 for gaussclumps , which straddle the Salpeter value ( \alpha = -2.35 ) .
The mass at which the slope shallows ( similar for both algorithms at M \approx 6 M _ { \odot } ) implies a star-forming efficiency of between 10 and 20 per cent .
Other trends reported elsewhere depend critically on the clump-finding technique : we find protostellar clumps are both smaller ( for gaussclumps ) and larger ( for clfind ) than their starless counterparts ; the functional form , best-fitting to the CMD , is different for the two algorithms .
The gaussclumps CMD is best-fitted with a log-normal distribution , whereas a broken power law is best for clfind ; the reported lack of massive starless cores in previous studies ( e.g . Hatchell et al . 25 ; Hatchell & Fuller 24 ) can be seen in the clfind but not the gaussclumps data .
Our approach , exploiting two extraction techniques , highlights similarities and differences between the clump populations , illustrating the caution that must be exercised when comparing results from different studies and interpreting the properties of samples of continuum cores .