Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spitzer IRAC Observations of Star Formation in N159 in the LMC   We present observations of the giant HII region complex N159 in the LMC using
IRAC on the {\it Spitzer Space Telescope}. One of the two objects previously
identified as protostars in N159 has an SED consistent with classification as a
Class I young stellar object (YSO) and the other is probably a Class I YSO as
well, making these two stars the youngest stars known outside the Milky Way. We
identify two other sources that may also be Class I YSOs. One component,
N159AN, is completely hidden at optical wavelengths, but is very prominent in
the infrared. The integrated luminosity of the entire complex is L $\approx
9\times10^6$L$_{\odot}$, consistent with the observed radio emission assuming a
normal Galactic initial mass function (IMF). There is no evidence for a red
supergiant population indicative of an older burst of star formation. The N159
complex is 50 pc in diameter, larger in physical size than typical HII regions
in the Milky Way with comparable luminosity. We argue that all of the
individual components are related in their star formation history. The
morphology of the region is consistent with a wind blown bubble $\approx
1-2Myr-old that has initiated star formation now taking place at the rim. Other
than its large physical size, star formation in N159 appears to be
indistinguishable from star formation in the Milky Way.

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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th