High-resolution observations of the molecular clouds in the NGC 1333 IRAS 4 region

The molecular outflows and the dense cores in the NGC 1333 IRAS 4 region were observed in several molecular lines and in the millimeter continuum with similar to4" angular resolution. The outflows were particularly well traced by the HCN line. The IRAS 4A northeast-southwestern outflow consists of several compact knots which are spaced regularly and have alternating position angles. This "wiggle" could be produced either by a "precessing " jet or by quasi-periodic outbursts of the driving source. In the former case, the binary separation causing either the precession or the "wobbling" of the protostellar disk should be smaller than the separation between IRAS 4A1 and 4A2. The HCN map shows yet another outflow to the south of IRAS 4A and a compact bipolar outflow driven by IRAS 4BI, but no outflow activity was found near IRAS 4BII. The central velocity of the IRAS 4A dense core is determined to be V-LSR = 6.7 km s(-1) using the (CO)-O-18 line. With this central velocity, the optically thick lines toward IRAS 4A are not significantly blue-skewed, and the double-peaked line profile may not be a signature of infall motion in this particular case. IRAS 4BII has a steeper spectral index from 3.4 to 2.7 mm than IRAS 4A/4BI, suggesting that IRAS 4BII may be more evolved than its companions.