Cores and cavities in NGC 1333

We present 1.3mm continuum and CS J = 5 → 4 maps at 12′′ resolution of the NGC1333 star forming region. The area covered is 8′ × 6′. The large-scale bolometer and CS maps delineate very nicely the large central cavity together with the cores situated in the surrounding compressed shell. In addition to the four dust cores IRAS4A-B, IRAS2 and SVS13, we discovered two fainter condensations, one of which is not associated with protostellar activity. All protostars are surrounded by extended low-emissivity envelopes and show indications of depletion of molecules onto grains. The continuum emission traces material entrained by the outflows powered by IRAS4A, IRAS2 and SVS13. The CS J = 5 → 4 is observed in all dust cores. Apart from IRAS4, the CS emission peak is shifted with respect to the dust continuum. The large-scale dust emission mostly comes from material compressed around two cavities, whose walls are detected in the H2 S(1) v= 1-0 line. These cavities seem to have been excavated by outflows from the neighboring protostars IRAS4 and SVS13, and are now expanding in the ambient medium. Taken together these new data suggest that the large cavity in NGC1333 grows by local action of stars forming in the compressed edge, each producing a local cavity which eventually overlap.