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A&A 397, 693-710 (2003)
DOI: 10.1051/0004-6361:20021545
Near-IR echelle spectroscopy of Class I protostars: Mapping Forbidden Emission-Line (FEL) regions in [FeII]
C. J. Davis1, E. Whelan2, T. P. Ray2 and A. Chrysostomou31 Joint Astronomy Centre, 660 North A'ohoku Place, University Park, Hilo, Hawaii 96720, USA
2 Dublin Institute for Advanced Studies, School of Cosmic Physics, 5 Merrion Square, Dublin 2, Ireland
3 Department of Physical Sciences, University of Hertfordshire, Hatfield, Herts AL10 9AB, UK
(Received 27 August 2002 / Accepted 22 October 2002 )
Abstract
Near-IR echelle spectra in [FeII] 1.644
m emission trace Forbidden
Emission Line (FEL) regions towards seven Class I HH energy sources
(SVS 13, B5-IRS1, IRAS 04239+2436, L1551-IRS5, HH 34-IRS,
HH 72-IRS and HH 379-IRS) and three classical T Tauri stars
(AS 353A, DG Tau and RW Aur). The parameters of these FEL regions
are compared to the characteristics of the Molecular Hydrogen Emission
Line (MHEL) regions recently discovered towards the same outflow
sources (Davis et al. 2001 - Paper I). The [FeII] and H
2 lines
both trace emission from the base of a large-scale collimated outflow,
although they clearly trace different flow components. We find that
the [FeII] is associated with higher-velocity gas than the H
2, and
that the [FeII] emission peaks further away from the embedded source
in each system. This is probably because the [FeII] is more closely
associated with HH-type shocks in the inner, on-axis jet regions,
while the H
2 may be excited along the boundary between the jet and
the near-stationary, dense ambient medium that envelopes the
protostar. Indeed, there is spatial and kinematic evidence that
[FeII] and the more typically-used optical emission lines, the red
[SII] doublet, do trace almost the same shock-excited regions in HH
jets and FEL regions alike.
Key words: ISM: jets and outflows -- stars: pre-main-sequence -- ISM: Herbig-Haro objects
Offprint request: C. J. Davis, c.davis@jach.hawaii.edu
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