AAS 199th meeting, Washington, DC, January 2002
Session 76. Disks and Outflows of Young Stellar Objects
Oral, Tuesday, January 8, 2002, 2:00-3:30pm, International Ballroom East

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[76.03] Subaru Telescope NIR Echelle Spectroscopy of L1551 IRS 5: A Partially Ionized Disk Wind under Collimation around an Ionized Fast Jet

T.-S. Pyo, M. Hayashi, N. Kobayashi, H. Terada, M. Goto, T. Yamashita (NAOJ), A. T. Tokunaga (UH IfA), Y. Itoh (Kobe U.)

We present a new [Fe~II] \lambda~1.644~\micron line image of the L1551 IRS~5 jets and its velocity resolved spectrum. The continuum subtracted [Fe~II] emission line image shows clearly separated two jet like features. A strong and spatially wide [Fe~II] emission feature was found elongated along the northern jet at its base. The echelle spectrum taken along the elongated feature shows two prominent velocity components and pedestal and wing emissions with the entire emission range blueshifted with respect to the systemic velocity. The high velocity component (HVC) at VLSR=-300~km~s-1 consistently shows narrow line width of ~40~km~s-1 along the northern jet. The HVC has a corresponding H\alpha emission. The low velocity component (LVC) at VLSR=-100~km~s-1 is located spatially closer to the IRS~5~(VLA) than is the HVC. The LVC shows broad line widths of 130--160~km~s-1 (FWHM) with flat topped line profiles in the region within 0\rlap.''8 from IRS~5~(VLA), while the line width decreases with increasing distance from it. The LVC has no corresponding H\alpha emission. We interpreted the velocity components as follows. The HVC is a narrow and well-collimated ionized stellar jet. The LVC is a widely opened and partially-ionized disk wind under collimation process. The pedestal and red wing features may represent the LVC gas entrained and accelerated by the HVC. The high velocity molecular and neutral atomic outflows in the literature may be entrained and accelerated by the LVC. Finally, we point out the possibility that the two apparently parallel jets seen more than 6'' away from IRS~5~(VLA) might be the brightened edges of the partially ionized wind.

The author(s) of this abstract have provided an email address for comments about the abstract: pyo@subaru.naoj.org

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