EDP Sciences
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Volume 372, Number 3, June IV 2001
Page(s) L41 - L44
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20010543

A&A 372, L41-L44 (2001)
DOI: 10.1051/0004-6361:20010543

A SCUBA survey of the NGC 2068/2071 protoclusters

F. Motte1, P. André2, D. Ward-Thompson3 and S. Bontemps4

1  Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
2  CEA/DSM/DAPNIA, Service d'Astrophysique, CE Saclay, 91191 Gif-sur-Yvette Cedex, France
3  Department of Physics & Astronomy, University of Cardiff, PO Box 913, Cardiff, UK
4  Observatoire de Bordeaux, BP 89, 33270 Floirac, France

(Received 18 January 2001 / Accepted 11 April 2001 )

We report the results of a submillimeter dust continuum survey of the protoclusters NGC 2068 and NGC 2071 in Orion B carried out at $850 \mu$m and $450 \mu$m with SCUBA on JCMT. The mapped region is ~ $32\arcmin \times 18\arcmin$ in size (~4 pc $\times$ 2 pc) and consists of filamentary dense cores which break up into small-scale (~5 000 AU) fragments, including 70 starless condensations and 5 circumstellar envelopes/disks. The starless condensations, seen on the same spatial scales as protostellar envelopes, are likely to be gravitationally bound and pre-stellar in nature. Their mass spectrum, ranging from ~0.3 $M_\odot$ to ~5 $M_\odot$, is reminiscent of the stellar initial mass function (IMF). Their mass-size relation suggests that they originate from gravitationally-driven fragmentation. We thus argue that pre-collapse cloud fragmentation plays a major role in shaping the IMF.

Key words: ISM: clouds -- ISM: structure -- dust -- stars: formation -- stars: initial mass function -- submillimeter

Offprint request: F. Motte or P. André, motte@submm.caltech.edu; pandre@cea.fr

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