Jet rotation: Launching region, angular momentum balance and magnetic properties in the bipolar outflow from RW Aur

• DOI: 10.1051/0004-6361:20034439
• Publication Date: 2005-02-22T13:04:24Z
• Authors: J. Woitas; F. Bacciotti; T. P. Ray; A. Marconi; D. Coffey; J. Eislöffel
• Keywords: Outflow; Bipolar outflow; Clockwise

Using STIS on board the HST we have obtained a spectroscopic map of bipolar jet from RW Aur with slit parallel to axis and moved across in steps . After applying velocity correction due uneven illumination find signatures rotation within first 300 AU (15 at distance Aur). Both lobes rotate same direction (i.e. different helicities), toroidal velocities range 5–30 km s-1 20 30 symmetry blueshifted redshifted lobes, respectively. The sense is anti-clockwise looking tip blue lobe (PA 130° north east) down star. Rotation more evident [OI] [NII] lines largest sampled axis. These results are consistent other observations carried out perpendicular axis, theoretical simulations. current magneto-hydrodynamic models for launch jets, that mass ejected observed part outflow accelerated region disk about 0.5 star lobe, 1.6 red lobe. also previous estimate upper lower limits angular momentum transport rate jet. We this can be large fraction (two thirds or more) estimated transported through relevant portion disk. magnetic lever arm (defined as ratio between Alfvèn footpoint radii) 3.5–4.6 (with an accuracy 20–25%), or, alternatively, ejection index 0.025–0.046 similar uncertainties). derived values predicted by models, but they suggest some heating must provided base flow. Finally, using general wind theory derive poloidal components field location 80–100 above disk). quantity (assuming cylindrical coordinates centred positive z along lobe). component appears dominant, which would collimation tightly wrapped side.