A molecular line study of the HH 7-11 outflow

Observations of the HH 7-11 outflow were carried out in multiple lines of C S and NH, in order to trace the structure of the outflow and its interactio n with the surrounding medium. The lower-J CS observations show evidence fo r a low-velocity (few km s(-1)) CS bipolar flow in the same sense as the CO outflow. A dense (greater than or similar to 10(6) cm(-3)) CS and NH3 ridg e 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 clas s 0 protostar that is placed similar to 15 " southwest of SVS 13-see the 19 98 work by Bachiller and colleagues). The CS observations at ambient veloci ties clearly show an evacuated cavity to the southeast of SVS 13, surroundi ng HH 10 and 11, and ending at a wide ridge of gas just downwind of HH 8. T he NH3 observations show evidence of gas heated to temperatures; greater th an or similar to 40 K in at least three distinct regions: in the vicinity o f 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 shoc k heating from wind-cloud interactions could be responsible; the gas downwi nd of HH 8 is either directly shock heated or is radiatively heated by the shock traced by HH 8.