Emission lines from rotating proto-stellar jets with variable velocity profiles. I. Three-dimensio

Using the Yguazu-a three-dimensional hydrodynamic code, we have computed a set of numerical simulations of heavy, supersonic, radiatively cooling jets including var iabilities in both the ejection direction (precession) and the jet velocity (intermittence). In order to investigate the effects of jet rotation on the shape of the line profiles, we also i ntroduce an initial toroidal rotation velocity profile, in agreement with some r ecent observational evidence found in jets from T Tauri stars which seems to support the presence of a rotation velocity pattern inside the jet beam, near the jet production region. Since th e Yguazu- a code includes an atomic/ionic network, we are able to compute the emission coeffi cients for several emission lines, and we generate line profiles for the H �, (O I)�6300, (S II)�6716 and (N II)�6548 lines. Using initial parameters that are suitable for the DG Tau microjet, we show that the computed radial velocity shift for the medium-velocity component of the line profile as a function of distance from the jet axis is strikingly simi lar for rotating and non-rotating jet models. These findings lead us to put forward some caveats on the interpretation of the observed radial velocity distribution from a few outflows from yo ung stellar objects, and we claim that these data should not be di rectly used as a doubtless confirmation of the magnetocentri fugal wind acceleration models.

[1]  Dublin Institute for Advanced Studies,et al.  Jet rotation: Launching region, angular momentum balance and magnetic properties in the bipolar outflow from RW Aur , 2004, astro-ph/0411119.

[2]  N. Soker.  Interaction of young stellar object jets with their accretion disk , 2004, astro-ph/0410537.

[3]  Brazil.,et al.  3-D numerical simulations of rotating jets - The case of the DG Tau microjet , 2004, astro-ph/0409285.

[4]  A. Raga,et al.  Models for the Infrared Cavity of HH 46/47 , 2004 .

[5]  A. Raga,et al.  Numerical Modeling of η Carinae Bipolar Outflows , 2004, astro-ph/0408588.

[6]  A. Riera,et al.  Time-dependent ejection velocity model for the outflow of Hen 3-1475 , 2004, astro-ph/0403126.

[7]  S. Cabrit,et al.  Predicted rotation signatures in MHD disc winds and comparison to DG Tau observations , 2004, astro-ph/0403236.

[8]  A. Raga,et al.  Effects of Thermal Conduction on the X-Ray and Synchrotron Emission from Supernova Remnants , 2004 .

[9]  T. Ray,et al.  Rotation of Jets from Young Stars: New Clues from the Hubble Space Telescope Imaging Spectrograph , 2003, astro-ph/0312300.

[10]  A. Raga,et al.  Gasdynamical Simulations of the Large and Little Homunculus Nebulae of η Carinae , 2003, astro-ph/0310010.

[11]  M. Hayashi,et al.  Adaptive Optics Spectroscopy of the [Fe II] Outflow from DG Tauri , 2003 .

[12]  T. Ray,et al.  Hubble Space Telescope Space Telescope Imaging Spectrograph Observations of the Bipolar Jet from RW Aurigae: Tracing Outflow Asymmetries Close to the Source , 2002 .

[13]  L. Testi,et al.  The kinematic relationship between disk and jet in the DG Tauri system , 2002, astro-ph/0209464.

[14]  T. Ray,et al.  HST/STIS observations of the bipolar jet from RW Aurigae. , 2002, astro-ph/0207307.

[15]  A. Raga,et al.  Analytic and Numerical Models for the Knots along the HH 111 Jet , 2002 .

[16]  P. Mininni,et al.  Jet/cloud collision, 3D gasdynamic simulations of HH 110 , 2002, astro-ph/0206242.

[17]  T. Ray,et al.  HST/STIS Spectroscopy of the Optical Outflow from DG Tau: Indications for Rotation in the Initial Jet Channel , 2002, astro-ph/0206175.

[18]  A. Raga,et al.  Herbig-Haro Jets from Orbiting Sources , 2002 .

[19]  M. Rosado,et al.  A single explosion model for the supernova remnant 3C 400.2 , 2001 .

[20]  Elena Masciadri,et al.  Simulated X-Ray Images and Spectra of the Arches Cluster , 2001 .

[21]  A. Raga,et al.  A numerical and experimental study of the time-evolution of a low Mach number jet , 2001 .

[22]  S. Cabrit,et al.  A precessing, variable velocity jet model for DG Tauri , 2001 .

[23]  M. Villagrán-Muniz,et al.  Temporal evolution of the shock wave and hot core air in laser induced plasma , 2000 .

[24]  L. Hartmann,et al.  A new optical extinction law and distance estimate for the Taurus-Auriga molecular cloud , 1994 .

[25]  Eve C. Ostriker,et al.  Magnetocentrifugally driven flows from young stars and disks. 1: A generalized model , 1994 .

[26]  L. Hartmann,et al.  Protostellar Mass and Angular Momentum Loss , 1982 .

[27]  R. Blandford,et al.  Hydromagnetic flows from accretion discs and the production of radio jets , 1982 .

[28]  Claudio Mendoza,et al.  Recent advances in atomic calculations and experiments of interest in the study of planetary nebulae , 1983 .