THE IRAS 2 AND IRAS 4 OUTFLOWS AND STAR FORMATION IN NGC 1333

摘要

We report the first detection of the western bow shock component from IRAS 2 in NGC 1333 along with observations of previously detected shocks and outflow winds from this source and those from IRAS 4. We compare the shock and outflow distributions from these two young stellar objects (YSOs), and the locations of other YSOs, with the overall distribution of the dense molecular gas in the star-forming core using high spatial resolution observations of CS (J = 2 → 1, 3 → 2, and 5→4) emission made with the Institut de Radio Astronomic Millimetrique 30 m antenna. These comparisons provide a new picture of the morphology and dynamics of the star-forming core of NGC 1333. The CS maps show (1) a large cavity with many YSOs just at the inner edge of the cavity, (2) a dense, compressed shell at 8 km s~(-1); and (3) a gas layer at 7 km s~(-1) probably located inside the cavity. We find that the IRAS 2 and IRAS 4 outflows impact different gas layers as indicated by the spatial association of the red- and blueshifted lobes, and that IRAS 2 is located near the front edge of the CS shell. The burst of star formation that has shaped NGC 1333 is occurring in the compressed shell traced by CS and now appears to be in a late evolutionary stage.