Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Search for Ionized Gas in the Draco and Ursa Minor Dwarf Spheroidal
  Galaxies   The Wisconsin H Alpha Mapper has been used to set the first deep upper limits
on the intensity of diffuse H alpha emission from warm ionized gas in the Local
Group dwarf spheroidal galaxies (dSphs) Draco and Ursa Minor. Assuming a
velocity dispersion of 15 km/s for the ionized gas, we set limits for the H
alpha intensity of less or equal to 0.024 Rayleighs and less or equal to 0.021
Rayleighs for the Draco and Ursa Minor dSphs, respectively, averaged over our 1
degree circular beam. Adopting a simple model for the ionized interstellar
medium, these limits translate to upper bounds on the mass of ionized gas of
approximately less than 10% of the stellar mass, or approximately 10 times the
upper limits for the mass of neutral hydrogen. Note that the Draco and Ursa
Minor dSphs could contain substantial amounts of interstellar gas, equivalent
to all of the gas injected by dying stars since the end of their main star
forming episodes more than 8 Gyr in the past, without violating these limits on
the mass of ionized gas.

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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc