Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Palomar Transient Factory and RR Lyrae: Metallicity-Light Curve Relation
  Based on ab-Type RR Lyrae in Kepler Field   The wide-field synoptic sky surveys, known as the Palomar Transient Factory
(PTF) and the intermediate Palomar Transient Factory (iPTF), will accumulate a
large number of known and new RR Lyrae. These RR Lyrae are good tracers to
study the substructure of the Galactic halo if their distance, metallicity, and
galactocentric velocity can be measured. Candidates of halo RR Lyrae can be
identified from their distance and metallicity before requesting spectroscopic
observations for confirmation. This is because both quantities can be obtained
via their photometric light curves, because the absolute V-band magnitude for
RR Lyrae is correlated with metallicity, and the metallicity can be estimated
using a metallicity-light curve relation. To fully utilize the PTF and iPTF
light-curve data in related future work, it is necessary to derive the
metallicity-light curve relation in the native PTF/iPTF R-band photometric
system. In this work, we derived such a relation using the known ab-type RR
Lyrae located in the Kepler field, and it is found to be $[Fe/H]_{PTF} = -4.089
- 7.346 P + 1.280 \phi_{31}$ (where $P$ is pulsational period and $\phi_{31}$
is one of the Fourier parameters describing the shape of the light curve), with
a dispersion of 0.118 dex. We tested our metallicity-light curve relation with
new spectroscopic observations of a few RR Lyrae in the Kepler field, as well
as several data sets available in the literature. Our tests demonstrated that
the derived metallicity-light curve relation could be used to estimate
metallicities for the majority of the RR Lyrae, which are in agreement with the
published values.

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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: math
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga