Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Formation of Constellation III in the Large Magellanic Cloud   We present a detailed reconstruction of the star-formation history of the
Constellation III region in the Large Magellanic Cloud, to constrain the
formation mechanism of this enigmatic feature. Star formation in Constellation
III seems to have taken place during two distinct epochs: there is the 8-15 Myr
epoch that had previously been recognized, but we also see strong evidence for
a separate "burst" of star formation 25-30 Myr ago. The "super-supernova" or
GRB blast wave model for the formation of Constellation III is difficult to
reconcile with such an extended, two-epoch star formation history, because the
shock wave should have induced star formation throughout the structure
simultaneously, and any unconsumed gas would quickly be dissipated, leaving
nothing from which to form a subsequent burst of activity. We propose a "truly
stochastic" self-propagating star formation model, distinct from the canonical
model in which star formation proceeds in a radially-directed wave from the
center of Constellation III to its perimeter. As others have noted, and we now
confirm, the bulk age gradients demanded by such a model are simply not present
in Constellation III. In our scenario, the prestellar gas is somehow pushed
into these large-scale arc structures, without simultaneously triggering
immediate and violent star formation throughout the structure. Rather, star
formation proceeds in the arc according to the local physical conditions of the
gas. Self-propagating star formation is certainly possible, but in a truly
stochastic manner, without a directed, large scale pattern.

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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc