Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The HST Key Project on the Extragalactic Distance Scale. XXII. The
  Discovery of Cepheids in NGC 1326-A   We report on the detection of Cepheids and the first distance measurement to
the spiral galaxy NGC 1326-A, a member of the Fornax cluster of galaxies. We
have employed data obtained with the Wide Field and Planetary Camera 2 on board
the Hubble Space Telescope. Over a 49 day interval, a total of twelve V-band
(F555W) and eight I-band (F814W) epochs of observation were obtained. Two
photometric reduction packages, ALLFRAME and DoPHOT, have been employed to
obtain photometry measures from the three Wide Field CCDs. Variability analysis
yields a total of 17 Cepheids in common with both photometry datasets, with
periods ranging between 10 and 50 days. Of these 14 Cepheids with high-quality
lightcurves are used to fit the V and I period-luminosity relations and derive
apparent distance moduli, assuming a Large Magellanic Cloud distance modulus
(m-M) (LMC) = 18.50 +- 0.10 mag and color excess E(B-V) = 0.10 mag. Assuming
A(V)/E(V-I) = 2.45, the DoPHOT data yield a true distance modulus to NGC 1326-A
of (m-M)_0 = 31.36 +- 0.17 (random) +- 0.13 (systematic) mag, corresponding to
a distance of 18.7 \pm 1.5 (random) \pm 1.2 (systematic) Mpc. The derived
distance to NGC 1326-A is in good agreement with the distance derived
previously to NGC 1365, another spiral galaxy member of the Fornax cluster.
However the distances to both galaxies are significantly lower than to NGC
1425, a third Cepheid calibrator in the outer parts of the cluster.

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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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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: solv-int
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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg