The Large and Small Scale Structures of Dust in the Star-Forming Perseus Molecular Cloud

We present an analysis of ∼3.5 square degrees of submillimetre continuum and extinction data of the Perseus molecular cloud. We identify 49 clumps in the submillimetre map and we identify 39 structures (‘cores’) and 11 associations of structures (‘super cores’) in the extinction map. The cumulative mass distributions of the submillimetre clumps and extinction cores have steep slopes (α ∼ 2 and 1.5 2 respectively), steeper than the Salpeter IMF (α = 1.35), while the distribution of extinction super cores has a shallow slope (α ∼ 1). Most of the submillimetre clumps are well fit by stable Bonnor-Ebert spheres with 10 K < T < 19 K and 5.5 < log10(Pext/k) < 6.0. The clumps are found only in the highest column density regions (AV > 5 7 mag), although Bonnor-Ebert models suggest that we should have been able to detect them at lower column densities if they exist. These observations provide a stronger case for an extinction threshold than that found in analysis of less sensitive observations of the Ophiuchus molecular cloud (Johnstone, Di Francesco, & Kirk 2004). The relationship between submillimetre clumps and their parent extinction core has been analyzed. The submillimetre clumps tend to lie offset from the larger extinction peaks, suggesting the clumps formed via an external triggering event, consistent with previous observations. Subject headings: infrared: ISM: continuum – ISM: individual (Perseus) – ISM: structure – stars: formation – submillimetre