Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dusty Nuclear Disks and Filaments in Early Type Galaxies   We examine the dust properties of a nearby distance-limited sample of early
type galaxies using the WFPC2 of the Hubble Space Telescope. Dust is detected
in 29 out of 67 galaxies (43%), including 12 with small nuclear dusty disks. In
a separate sample of 40 galaxies biased for the detection of dust by virtue of
their detection in the IRAS 100 micron band, dust is found in ~78% of the
galaxies, 15 of which contain dusty disks. In those galaxies with detectable
dust, the apparent mass of the dust correlates with radio and far infrared
luminosity, becoming more significant for systems with filamentary dust. A
majority of IRAS and radio detections are also associated with dusty galaxies
rather than dustless galaxies. This indicates that thermal emission from
clumpy, filamentary dust is the main source of the far-IR radiation in early
type galaxies. Dust in small disk-like morphology tends to be well aligned with
the major axis of the host galaxies, while filamentary dust appears to be more
randomly distributed with no preference for alignment with any major galactic
structure. This suggests that, if the dusty disks and filaments have a common
origin, the dust originates externally and requires time to dynamically relax
and settle in the galaxy potential in the form of compact disks. More galaxies
with visible dust than without dust display emission lines, indicative of
ionized gas, although such nuclear activity does not show a preference for
dusty disk over filamentary dust. There appears to be a weak relationship
between the mass of the dusty disks and central velocity dispersion of the
galaxy, suggesting a connection with a similar recently recognized relationship
between the latter and the black hole mass.

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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: hep-ph
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The categories of this paper are: mtrl-th