Molecular Hydrogen Kinematics in Cepheus A

We present the radial velocity structure of the molecular hydrogen outflows associated with the star-forming region Cepheus A. This structure is derived from the Doppler shift of the H2 v = 1–0 S(1) emission line obtained by Fabry-Pérot spectroscopy. The east and west regions of emission, called Cep A (E) and Cep A (W), show radial velocities in the range of -20 to 0 km s-1 with respect to the molecular cloud. Cep A (W) shows an increasing velocity with position offset from the core, indicating the existence of a possible accelerating mechanism. Cep A (E) has an almost constant mean radial velocity of -18 km s-1 along the region, although with a large dispersion in velocity, indicating the possibility of a turbulent outflow. A detailed analysis of the Cep A (E) region shows evidence for the presence of a Mach disk on that outflow. In addition, we argue that the presence of a velocity gradient in Cep A (W) is indicative of a C-shock in this region. Following Riera and coworkers, we analyzed the data using wavelet analysis to study the line width and central radial velocity distributions. We found that both outflows have complex spatial and velocity structure characteristic of a turbulent flow.