Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopy of Low Surface Brightness Galaxies with the Hobby-Eberly
  Telescope   We have obtained low resolution spectra of nineteen red and blue low surface
brightness galaxies, using the Marcario Low Resolution Spectrograph on the 9.2m
Hobby-Eberly Telescope. These galaxies form a very heterogeneous class, whose
spectra qualitatively resemble those of high surface brightness galaxies
covering the full range of spectra seen in galaxies of Hubble types from E to
Irr. We use a combination of emission line (EW(Halpha), NII/Halpha) and
absorption line (Mgb, Hbeta, <Fe>) based diagnostics to investigate the
star-formation and chemical enrichment histories of these galaxies. These are
diverse, with some galaxies having low metallicity and very young mean stellar
ages, and other galaxies showing old, super-solar metallicity stellar
populations. In contrast with some previous studies which found a strong trend
of decreasing metallicity with decreasing central surface brightness, we find a
population of galaxies with low surface brightness and near-solar metallicity.
Correlations between several of the gas phase and stellar population age and
metallicity indicators are used to place contraints on plausible evolutionary
scenarios for LSB galaxies. The redshift range spanned by these galaxies is
broad, with radial velocities from 3400 km/s to more than 65000 km/s. A subset
of the sample galaxies have published HI redshifts and gas masses based on
observations with the Arecibo 305m single-dish radio telescope, which place
these galaxies far off of the mean Tully-Fisher relation. Our new optical
redshifts do not agree with the published HI redshifts for these galaxies. Most
of the discrepancies can be explained by beam confusion in the Arecibo
observations, causing erroneous HI detections for some of the galaxies.

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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
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The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph
16
The categories of this paper are: stat
3
The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: atom-ph