Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A spectroscopic study of blue supergiant stars in Local Group spiral
  galaxies: Andromeda and Triangulum   Low-resolution LAMOST and Keck spectra of blue supergiant stars distributed
over the disks of the Local Group spiral galaxies M 31 and M 33 are analyzed to
determine stellar effective temperatures, gravities, metallicities, and
reddening. Logarithmic metallicities at the center of the galaxies (in solar
units) of $0.30\pm0.09$ and $0.11\pm0.04$ and metallicity gradients of
$-0.37\pm0.13$ dex/$R_{25}$ and $-0.36\pm0.16$ dex/$R_{25}$ are measured for M
31 and M 33, respectively. For M 33 the 2-dimensional distribution of
metallicity indicates a deviation from azimutal symmetry with an off-centre
peak. The flux-weighted gravity-luminosity relationship of blue supergiant
stars is used to determine a distance modulus of 24.51$\pm$0.13 mag for M 31
and 24.93$\pm$0.07 mag for M 33. For M 31 the flux-weighted gravity--luminosity
relationship (FGLR) distance agrees well with other methods. For M 33 the
FGLR-based distance is larger than the distances from Cepheids studies but it
is in good agreement with work on eclipsing binaries, planetary nebulae ,
long-period variables, and the tip of the red giant branch.

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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
18
The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-th
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The categories of this paper are: stat