Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Neighboring Dwarf Irregular Galaxy Hidden by the Milky Way   We have obtained VLA and optical follow-up observations of the low-velocity H
I source HIZSS 3 discovered by Henning et al. (2000) and Rivers (2000) in a
survey for nearby galaxies hidden by the disk of the Milky Way. Its radio
characteristics are consistent with this being a nearby (~1.8 Mpc) low-mass
dwarf irregular galaxy (dIm). Our optical imaging failed to reveal a resolved
stellar population, but did detect an extended H-alpha emission region. The
location of the H-alpha source is coincident with a partially-resolved H I
cloud in the 21-cm map. Spectroscopy confirms that the H$\alpha$ source has a
similar radial velocity to that of the H I emission at this location, and thus
we have identified an optical counterpart. The H$\alpha$ emission (100 pc in
diameter and with a luminosity of $1.4\times10^{38}$ ergs s$^{-1}$) is
characteristic of a single H II region containing a modest population of OB
stars. The galaxy's radial velocity and distance from the solar apex suggests
that it is not a Local Group member, although a more accurate distance is
needed to be certain. The properties of HIZSS 3 are comparable to those of GR
8, a nearby dIm with a modest amount of current star formation. Further
observations are needed to characterize its stellar population, determine the
chemical abundances, and obtain a more reliable distance estimate.

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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: cs
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The categories of this paper are: math
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: bayes-an