Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High resolution optical and infrared spectroscopic observations of Cir
  X-1   We present new optical and infrared (IR) observations of Cir X-1 taken near
apastron. Both sets of spectra show asymmetric emission lines. Archival optical
observations show that an asymmetric H-alpha emission line has been in evidence
for the past twenty years, although the shape of the line has changed
significantly. We present an eccentric (e ~ 0.7-0.9) low mass binary model,
where the system consists of a neutron star orbiting around a (sub-)giant
companion star of 3-5 solar masses. We suggest that the broad components of the
emission lines arise in a high-velocity, optically thick flow near the neutron
star; while the narrow components of the optical and the IR lines arise near
the companion star and a heated ejecta-shell surrounding the binary
respectively. In this model, the velocity of the narrow component reflects the
space velocity of the binary; the implied radial velocity (+430 km/s after
correcting for Galactic rotation) is the highest velocity known for an X-ray
binary.

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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: solv-int
3
The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys
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The categories of this paper are: eess