Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HST WFPC-2 Imaging of UGC 12695: A Remarkably Unevolved Galaxy at Low
  Redshift   Utilizing the F814W and F300W filters, short exposure HST WFPC-2 images were
taken of UGC 12695 a nearby (z ~ 0.021) low surface brightness disk galaxy. UGC
12695 has an unusual morphology, consisting of a Y-shaped nucleus surrounded by
a faint spiral arm with a number of bright H II regions interspersed throughout
the galaxy. Surface photometry indicates the majority of recent star formation
in this galaxy occurred in these very localized regions, most of which have a
radius of < 2''. This uneven stellar distribution combined with the galaxy's
overall extremely blue color and low metallicity indicates UGC 12695 is an
unevolved galaxy.
  Some of the structural peculiarities of this galaxy arise because a number of
background galaxies, previously thought to be morphological components of this
galaxy, are showing through both the outer nucleus and spiral arms of UGC
12695. Surface photometry of these galaxies shows them to be fairly small
(alpha < 1.8'') disk galaxies with total magnitudes ranging from 19.6 through
24.2, and central surface brightnesses between 20.2 mag/arcsec^2 < mu(0) < 23.1
mag/arcsec^2. When possible, the U, B, V, and I colors of these galaxies were
measured using ground-based images, which show the galaxies to be fairly red
indicatingthey are likely at redshifts z > 0.5.Inclusion of them in the
photometry of UGC 12695 makes the galaxyappear significantly redder. When these
galaxies are masked out, the resultant U-I color of UGC 12695 is -0.2 +/- 0.1,
making it perhaps the bluest galaxy every measured in this color system and
confirming its nature as a very unevolved galaxy at low redshift.Spectroscopy
of these background galaxies, through the transparent disk of UGC 12695, may
help to clarify its chemical evolution and current heavy element content.

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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: math-ph
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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: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg