Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Visible and dark matter in M31 - I. Properties of stellar components   We construct a structural model of the Andromeda Galaxy, simultaneously
corresponding to observed photometrical and kinematical data and chemical
abundances. In this paper we present the observed surface brightness, colour
and metallicity distributions, and compare them to the model galaxy. In Paper
II (Tempel, Tamm & Tenjes 2007) we present similar data for the kinematics, and
derive the mass distribution of the galaxy. On the basis of U, B, V, R, I and L
luminosity distributions, we construct the model galaxy as a superposition of
four axially symmetric stellar components: a bulge, a disc, an inner halo and
an extended diffuse halo. By using far-infrared imaging data of M31 and a thin
dust disc assumption, we derive dust-free surface brightness and colour
distributions. We find the total absorption corrected luminosity of M31 to be
L_B = (3.3+/-0.7)x10^10 L_sun, corresponding to an absolute luminosity M_B =
-20.8+/-0.2 mag. Of the total luminosity, 41% (0.57 mag) is obscured from us by
the dust inside M31. Using chemical evolution models, we calculate
mass-to-light ratios of the components, correspoding to the colour indices and
metallicities. We find the total intrinsic mass-to-light ratio of the visible
matter to be M/L_B=3.1-5.8 M_sun/L_sun and the total mass of visible matter
M_vis =(10-19)x10^10 M_sun. The use of the model parameters for a dynamical
analysis and for determining dark matter distribution is presented in Paper II.

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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
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The categories of this paper are: solv-int
1
The categories of this paper are: cs
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex