Infall and outflow detections in a massive core JCMT 18354-0649S

We present a high-resolution study of a massive dense core JCMT 18354-0649S with the Submillimeter Array. The core is mapped with continuum emission at 1.3 mm, and molecular lines including CH${}_3$OH ($5_{23}$-$4_{13}$) and HCN (3-2). The dust core detected in the compact configuration has a mass of $47 M_{\odot}$andadiameterof$2\arcsec$ (0.06 pc), which is further resolved into three condensations with a total mass of $42M_{\odot }$ under higher spatial resolution. The HCN (3-2) line exhibits asymmetric profile consistent with infall signature. The infall rate is estimated to be $2.0\times10^{-3} M_{\odot}\cdot$yr$^{-1}$. The high velocity HCN (3-2) line wings present an outflow with three lobes. Their total mass is $12M_{\odot }$ and total momentum is $121M_{\odot }\cdot$km s${}^{-1}$, respectively. Analysis shows that the N-bearing molecules especially HCN can trace both inflow and outflow.