High-resolution observations of the molecular clouds in the NGC 1333 IRAS 4 region.
Abstract (from CDS):
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 ∼4'' 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 VLSR=6.7 km.s–1 using the C18O 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.