Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Far-Ultraviolet Observations of RR Lyrae Stars in the Core of NGC 1851   There are extraordinarily few far ultraviolet observations of RR Lyrae stars
in the literature. We present Hubble Space Telescope FUV (~1600 A) imaging of
the core of the globular cluster NGC 1851. Eleven new variables whose light
curves are consistent with those of RR Lyr stars are discovered, increasing the
total number of RR Lyr known in this cluster by a substantial amount. In
agreement with basic physical theory, the observed amplitude of the variables
in the FUV is enormous compared with the century of past optical observations,
ranging up to 4 mag. HST STIS FUV observations of cluster cores may prove an
especially effective means of obtaining a near-complete census of RR Lyr stars,
combining high angular resolution, suppression of luminous red stars, and data
where the stellar pulsation amplitudes are greatly enhanced. Attention is also
drawn to a peculiar blue object in the cluster that is most probably a low mass
x-ray binary system in quiescence.

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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
3
The categories of this paper are: physics
1
The categories of this paper are: cs
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The categories of this paper are: eess
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio