Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Intrinsic Shape of Galaxies in SDSS/Galaxy Zoo   By modelling the axis ratio distribution of SDSS DR8 galaxies we find the
intrinsic 3D shapes of spirals and ellipticals. We use morphological
information from the Galaxy Zoo project and assume a non-parametric
distribution intrinsic of shapes, while taking into account dust extinction.
  We measure the dust extinction of the full sample of spiral galaxies and find
a smaller value than previous estimations, with an edge-on extinction of $E_0 =
0.284^{+0.015}_{-0.026}$ in the SDSS r band. We also find that the distribution
of minor to major axis ratio has a mean value of $ 0.267 \pm 0.009 $, slightly
larger than previous estimates mainly due to the lower extinction used; the
same affects the circularity of galactic discs, which are found to be less
round in shape than in previous studies, with a mean ellipticity of $0.215 \pm
0.013$.
  For elliptical galaxies, we find that the minor to major axis ratio, with a
mean value of $0.584 \pm 0.006$, is larger than previous estimations due to the
removal of spiral interlopers present in samples with morphological information
from photometric profiles. These interlopers are removed when selecting
ellipticals using Galaxy Zoo data.
  We find that the intrinsic shapes of galaxies and their dust extinction vary
with absolute magnitude, colour and physical size. We find that bright
elliptical galaxies are more spherical than faint ones, a trend that is also
present with galaxy size, and that there is no dependence of elliptical galaxy
shape with colour. For spiral galaxies we find that the reddest ones have
higher dust extinction as expected, due to the fact that this reddening is
mainly due to dust. We also find that the thickness of discs increases with
luminosity and size, and that brighter, smaller and redder galaxies have less
round discs.

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The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
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The categories of this paper are: stat
20
The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
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The categories of this paper are: plasm-ph