Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ALFALFA Discovery of the Nearby Gas-rich Dwarf Galaxy Leo P. V. Neutral
  Gas Dynamics and Kinematics   We present new HI spectral line imaging of the extremely metal-poor,
star-forming dwarf irregular galaxy Leo P. Our HI images probe the global
neutral gas properties and the local conditions of the interstellar medium
(ISM). The HI morphology is slightly elongated along the optical major-axis. We
do not find obvious signatures of interaction or infalling gas at large spatial
scales. The neutral gas disk shows obvious rotation, although the velocity
dispersion is comparable to the rotation velocity. The rotation amplitude is
estimated to be V_c = 15 +/- 5 km/s. Within the HI radius probed by these
observations, the mass ratio of gas to stars is roughly 2:1, while the ratio of
the total mass to the baryonic mass is ~15:1. We use this information to place
Leo P on the baryonic Tully-Fisher relation, testing the baryonic content of
cosmic structures in a sparsely populated portion of parameter space that has
hitherto been occupied primarily by dwarf spheroidal galaxies. We detect the
signature of two temperature components in the neutral ISM of Leo P; the cold
and warm components have characteristic velocity widths of 4.2 +/- 0.9 km/s and
10.1 +/- 1.2 km/s, corresponding to kinetic temperatures of ~1100 K and ~6200
K, respectively. The cold HI component is unresolved at a physical resolution
of 200 pc. The highest HI surface densities are observed in close physical
proximity to the single HII region. A comparison of the neutral gas properties
of Leo P with other extremely metal-deficient (XMD) galaxies reveals that Leo P
has the lowest neutral gas mass of any known XMD, and that the dynamical mass
of Leo P is more than two orders of magnitude smaller than any known XMD with
comparable metallicity.

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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: chem-ph
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The categories of this paper are: math
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: cond-mat
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th