Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The dynamics of the nebula M1-67 around the run-away Wolf-Rayet star WR
  124   A new point of view on the dynamics of the circumstellar nebula M1-67 around
the run-away Wolf-Rayet (WR) star WR 124 is presented. We found that it has
been interacting with the surrounding ISM and has formed a bow shock due to its
high velocity of about 180 km/s relative to the local ISM. The star is about
1.3 parsec away from the front of this bow shock. The outbursts that are
responsible for the nebula are assumed to be discrete outbursts that occurred
inside this bow shock. The ejecta collide with this bow shock shortly after the
outburst. After the collision, they are dragged away by the pressure of the
ISM, along the surface of the bow shock. The bow shock is oriented in such way
that we are looking from the rear into this paraboloid, almost along the main
axis. Evidence for this is given firstly by the fact that the far hemisphere is
much brighter than the near hemisphere, secondly by the fact that there is
hardly any emission found with radial velocities higher than the star's radial
velocity, thirdly by the fact that the star looks to be in the centre of the
nebula, as seen from Earth, and finally by the asymmetric overall velocity
distribution of the nebula, which indicates higher radial velocities in the
centre of the nebula, and lower velocities near the edges. We find evidence for
at least two discrete outbursts that occurred inside this bow shock. For these
outbursts, we find expansion velocities of about 150 km/s and dynamical
timescales of about 8 and 20 kyr, which are typical values for LBV outbursts.
We therefore conclude that M1-67 originates from several outbursts that
occurred inside the bow shock around WR 124, during an LBV phase that preceded
the current WR phase of the star.

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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat