Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Why Are Rotating Elliptical Galaxies Less Elliptical at X-ray
  Frequencies?   If mass and angular momentum were conserved in cooling flows associated with
luminous, slowly rotating elliptical galaxies, the inflowing hot gas would spin
up, resulting in disks of cold gas and X-ray images that are highly flattened
along the equatorial plane out to several effective radii. Such X-ray
flattening is not observed at the spatial resolution currently available to
X-ray observations. Evidently mass and angular momentum are not in fact
conserved. If cooling flows are depleted by localized radiative cooling at
numerous sites distributed throughout the flows, then disks of cooled gas do
not form and the X-ray images appear nearly circular. However, the distribution
of young stars formed from the cooled gas is still somewhat flattened relative
to the stellar light. X-ray images of galactic cooling flows can also be
circularized by the turbulent diffusion of angular momentum away from the axis
of rotation, but the effective viscosity of known processes -- stellar mass
loss, supernovae, cooling site evolution, etc. -- is insufficient to
appreciably circularize the X-ray images. Radial gradients in the interstellar
iron abundance are unaffected by the expected level of interstellar turbulence
since these gradients are continuously re-established by Type Ia supernovae.

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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
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The categories of this paper are: q-alg
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-th
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph