ar X iv : a st ro - p h / 06 11 86 5 v 1 2 8 N ov 2 00 6 The Structure of the Inner HH 34 Jet from Optical Integral Field Spectroscopy

We present high spatial resolution optical integral field spectroscopy of a collimated Herbig-Haro jet viewed nearly edge-on. Maps of the line emission, velocity centroid, and velocity dispersion were generated for the Hα and [S II] emission features from the inner collimated jet and exciting source region of the HH 34 outflow. The kinematic structure of the jet shows several maxima and minima in both velocity centroid value and velocity dispersion along the jet axis. Perpendicular to the flow direction the velocity decreases outward from the axis to the limb of the jet, but the velocity dispersion increases. Maps of the electron density structure were derived from the line ratio of [S II] 6731/6716 emission. We have found that the jet exhibits a pronounced “striped” pattern in electron density; the high ne regions are at the leading side of each of the emission knots in the collimated jet, and low ne regions in the down-flow direction. On average, the measured electron density decreases outward from the inner regions of the jet, but the highest ne found in the outflow is spatially offset from the nominal position Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina). Gemini Observatory, Northern Operations, 670 N. A’ohoku Pl., Hilo, HI, 96720 Departament de F́ısica i Enginyeria Nuclear, Universitat Politécnica de Catalunya, Av. Vı́ctor Balaguers/n E-08800 Vilanova i La Geltrú, Spain Departament d’Astronomia i Meteorologia, Universitat de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Spain Instituto de Ciencias Nucleares, UNAM, Ap. 70-543, 04510 D.F., México Institute for Astronomy, University of Hawaii, 640 N. A’ohoku Pl. Hilo, HI 96720