Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New Results on the Helium Stars in the Galactic Center Using BEAR
  Spectro-Imagery   Integral field spectroscopy of the central parsec of the Galactic Center was
obtained at 2.06 microns using BEAR, an imaging Fourier Transform Spectrometer,
at a spectral resolution of 74 km/s. Sixteen stars were confirmed as helium
stars by detecting the He I 2.058 microns line in emission, providing a
homogeneous set of fully resolved line profiles.
  These observations allow us to discard some of the earlier detections of such
stars in the central cluster and to add three new stars. The sources detected
in the BEAR data were compared with adaptive optics images in the K band to
determine whether the emission was due to single stars. Two sub-classes of
almost equal number are clearly identified from the width of their line
profiles, and from the brightness of their continuum.
  Most of the emission lines show a P Cygni profile. From these results, we
propose that the latter group is formed of stars in or near the LBV phase, and
the other one of stars at the WR stage. The division into two groups is also
shown by their spatial distribution, with the narrow-line stars in a compact
central cluster (IRS 16) and the other group distributed at the periphery of
the central cluster of hot stars. In the same data cube, streamers of
interstellar helium gas are also detected.
  The helium emission traces the densest parts of the SgrA West Mini-Spiral.
Several helium stars have a radial velocity comparable to the velocity of the
interstellar gas in which they are embedded. In the final discussion, all these
findings are examined to present a possible scenario for the formation of very
massive stars in the exceptional conditions of the vicinity of the central
Black Hole.

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The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th