Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The young population of the Chamaeleon II dark cloud   We discuss the results of the optical spectroscopic follow-up of pre-main
sequence (PMS) objects and candidates selected in the Chamaeleon II dark cloud
based on data from the Spitzer Legacy survey "From Molecular Cores to Planet
Forming Disks" (c2d) and from previous surveys. Our sample includes both
objects with infrared excess selected according to c2d criteria and referred to
as Young Stellar Objects and other cloud members and candidates selected from
complementary optical and near-infrared data. We characterize the sample of
objects by deriving their physical parameters. The vast majority of objects
have masses < 1 solar mass and ages < 6 Myr. Several of the PMS objects and
candidates lie very close to or below the Hydrogen-burning limit. A first
estimate of the slope of the Initial Mass Function in Cha II is consistent with
that of other T associations. The star formation efficiency in the cloud (1-4%)
is consistent with our own estimates for Taurus and Lupus, but significantly
lower than for Cha I. This might mean that different star-formation activities
in the Chamaeleon clouds may reflect a different history of star formation. We
also find that the Cha II cloud is turning some 8 solar masses into stars every
Myr, which is less than the star formation rate in the other c2d clouds.
However, the star formation rate is not steady and evidence is found that the
star formation in Cha II might have occurred very rapidly. The H_alpha emission
of the Cha II PMS objects, as well as possible correlations between their
stellar and disk properties, are also investigated.

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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: math-ph