2001ApJ...558..204R

Observations of the HH 7-11 outflow were carried out in multiple lines of CS and NH₃ in order to trace the structure of the outflow and its interaction with the surrounding medium. The lower-J CS observations show evidence for a low-velocity (few km.s^–1) CS bipolar flow in the same sense as the CO outflow. A dense (≳10⁶ cm^–3) CS and NH₃ ridge perpendicular to the outflow is seen around SVS 13 (the driving source of the outflow), VLA 3 (a recently detected 6 cm source), and SVS 13B (a class 0 protostar that is placed ∼15" southwest of SVS 13–see the 1998 work by Bachiller and colleagues). The CS observations at ambient velocities clearly show an evacuated cavity to the southeast of SVS 13, surrounding HH 10 and 11, and ending at a wide ridge of gas just downwind of HH 8. The NH₃ observations show evidence of gas heated to temperatures ≳40 K in at least three distinct regions: in the vicinity of SVS 13 and VLA 3, just downwind of HH 8, and near SVS 13B. In the case of the circumstellar material, either heating by the embedded star(s) or shock heating from wind-cloud interactions could be responsible; the gas downwind of HH 8 is either directly shock heated or is radiatively heated by the shock traced by HH 8.