Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral mapping of the spiral structures in IP Pegasi on the decline
  from an outburst   (abridged) We report eclipse mapping of time resolved spectroscopy of the
dwarf nova IP Pegasi on the late decline from the May 1993 outburst. The spiral
arms are still visible some 8 days after the onset of the outburst. Their
fractional contribution to the continuum emission is similar to that measured
close to outburst maximum, whereas their orientation is rotated by 58 degrees
with respect to the spirals seen in the eclipse map at outburst maximum.
Velocity-resolved light curves across the Halpha and the HeI lines show the
classical rotational disturbance, with the blue side of the line being eclipsed
earlier than the red side. The differences between the Halpha and the HeI maps
are significant. The spiral arms are clearly seen in the HeI maps, with the
receding arm being stronger in the red side while the approaching arm is
stronger in the blue side of the line. The analysis of the Halpha maps suggests
that this emission arises mainly from a large and vertically-extended region
which we interpret as an outflowing (and spiraling) disc wind. The spectrum of
the uneclipsed light is dominated by a strong, blueshifted and narrow Halpha
emission line superimposed on a red continuum and can be understood as a
combination of emission from an M5V secondary star plus optically thin emission
from the outer parts of the vertically-extended disc wind. The inner disc
regions show an emission line spectrum with a strong and broad Halpha component
superimposed on a flat continuum. This is in marked contrast with the results
from the spectral mapping of nova-like variables of comparable inclination and
mass ratio and suggests that intrinsically different physical conditions hold
in the inner disc regions of outbursting dwarf novae and nova-like systems.

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The categories of this paper are: physics
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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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: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: patt-sol