2004/03/01 by N. Pesenti, C. Dougados, S. Cabrit +7 · 4 citations
Mathematics · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Geodesy #Geology #Geometry #Geophysics #Ionosphere and magnetosphere dynamics #Magnetohydrodynamics #Mathematics #Mechanics #Nuclear physics #Physics #Plasma #Rotation (mathematics) #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.1051/0004-6361:20040033
published as Astron.Astrophys. 416 (2004) L9 · 4 Pages, 4 Figures, to be published in A&A
openalex publication_date 2004/03/01 · arxiv created 2004/03/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Motivated by the first detections of rotation signatures in the DG Tau jet (Bacciotti et al. [CITE]), we examine possible biases affecting the relation between detected rotation signatures and true azimuthal velocity for self-similar MHD disc winds, taking into account projection, convolution as well as excitation gradients effects. We find that computed velocity shifts are systematically smaller than the true underlying rotation curve. When outer slower streamlines dominate the emission, we predict observed shifts increasing with transverse distance to the jet axis, opposite to the true rotation profile. Determination of the full transverse rotation profile thus requires high angular resolution observations (<5 AU) on an object with dominant inner faster streamlines. Comparison of our predictions with HST/STIS observations of DG Tau clearly shows that self-similar, warm MHD disc wind models with and an outer radius of the disc 3 AU are able to reproduce detected velocity shifts, while cold disc wind models () are ruled out for the medium-velocity component in the DG Tau jet.