Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence of Star Formation in Local S0 Galaxies: Spitzer Observations of
  the SAURON Sample   We discuss infrared Spitzer observations of early type galaxies in the SAURON
sample at 24, 60 and 170 microns. When compared with 2MASS Ks band
luminosities, lenticular (S0) galaxies exhibit a much wider range of mid to
far-infrared luminosities then elliptical (E) galaxies. Mid and far-infrared
emission from E galaxies is a combination of circumstellar or interstellar
emission from local mass-losing red giant stars, dust buoyantly transported
from the galactic cores into distant hot interstellar gas and dust accreted
from the environment. The source of mid and far-IR emission in S0 galaxies is
quite different and is consistent with low levels of star formation, 0.02 - 0.2
Msol/yr, in cold, dusty gaseous disks. The infrared 24micron-70micron color is
systematically lower for (mostly S0) galaxies with known molecular disks. Our
observations support the conjecture that cold dusty gas in some S0 galaxies is
created by stellar mass loss at approximately the same rate that it is consumed
by star formation, so the mass depletion of these disks by star formation will
be slow. Unlike E galaxies, the infrared luminosities of S0 galaxies correlate
with both the mass of molecular gas and the stellar Hbeta spectral index, and
all are related to the recent star formation rate. However, star formation
rates estimated from the Hbeta emission line luminosities L_{Hbeta} in SAURON
S0 galaxies are generally much smaller. Since L_{Hbeta} does not correlate with
24 microns emission from dust heated by young stars, optical emission lines
appear to be a poor indicator of star formation rates in SAURON S0 galaxies.
The absence of Hbeta emission may be due to a relative absence of OB stars in
the initial mass function or to dust absorption of Hbeta emission lines.

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The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin