Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigating the transport of angular momentum from young stellar
  objects: do H2 jets from Class I YSOs rotate?   In this pilot study, we examine molecular jets from the embedded Class I
sources, HH 26 and HH 72, to search, for the first time, for kinematic
signatures of jet rotation from young embedded sources.High resolution
long-slit spectroscopy of the H2 1-0 S(1) transition was obtained using
VLT/ISAAC, position-velocity (PV) diagrams constructed and intensity-weighted
radial velocities transverse to the jet flow measured. Mean intensity-weighted
velocities vary between vLSR ~ -90 and -65 km/s for HH 26, and -60 and -10 km/s
for HH 72; maxima occur close to the intensity peak and decrease toward the jet
borders. Velocity dispersions are ~ 45 and ~ 80 km/s for HH 26 and HH 72,
respectively, with gas motions as fast as -100 km/s present. Asymmetric PV
diagrams are seen for both objects which a simple empirical model of a
cylindrical jet section shows could in principle be reproduced by jet rotation
alone. Assuming magneto-centrifugal launching, the observed HH 26 flow may
originate at a disk radius of 2-4 AU from the star with the toroidal component
of the magnetic field dominant at the observed location, in agreement with
magnetic collimation models. We estimate that the kinetic angular momentum
transported by the HH 26 jet is ~ 2E5 M_sun/yr AU km/s. This value (a lower
limit to the total angular momentum transported by the flow) already amounts to
70% of the angular momentum that has to be extracted from the disk for the
accretion to proceed at the observed rate.
  The results of this pilot study suggest that jet rotation may also be present
at early evolutionary phases and supports the hypothesis that they carry away
excess angular momentum, thus allowing the central protostar to increase its
mass.

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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: math
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The categories of this paper are: econ
5
The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: nlin