Predicted rotation signatures in MHD disc winds and comparison to DG Tau observations

• Type: Article in International Scientific Journal
• Date: 2004

Authors

N. Pesenti (Author) Other; C. Dougados (Author) Other; S. Cabrit (Author) Other; J. Ferreira (Author) Other; F. Casse (Author) Other; Paulo Garcia (Author) FEUP; D. O'Brien (Author) Other

Journal

Title: Astronomy and Astrophysics

Vol. 416 No. 3

Pages: L9-L12

ISSN: 0004-6361

Publisher: EDP Sciences

Indexing

ISI Web of Knowledge - 61 Citations

ISI Web of Science

Scopus - 64 Citations

Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Authenticus ID: P-000-B9W

DOI: 10.1051/0004-6361:20040033

Abstract (EN): Motivated by the first detections of rotation signatures in the DG Tau jet (Bacciotti et al. 2002), 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 λ = 13 and an outer radius of the disc &SIME;3 AU are able to reproduce detected velocity shifts, while cold disc wind models (λ > 50) are ruled out for the medium-velocity component in the DG Tau jet.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4