Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cluster Density and the IMF   Observed variations in the IMF are reviewed with an emphasis on environmental
density. The remote field IMF studied in the LMC by several authors is clearly
steeper than most cluster IMFs, which have slopes close to the Salpeter value.
Local field regions of star formation, like Taurus, may have relatively steep
IMFs too. Very dense and massive clusters, like super star clusters, could have
flatter IMFs, or inner-truncated IMFs. We propose that these variations are the
result of three distinct processes during star formation that affect the mass
function in different ways depending on mass range. At solar to intermediate
stellar masses, gas processes involving thermal pressure and supersonic
turbulence determine the basic scale for stellar mass, starting with the
observed pre-stellar condensations, and they define the mass function from
several tenths to several solar masses. Brown dwarfs require extraordinarily
high pressures for fragmentation from the gas, and presumably form inside the
pre-stellar condensations during mutual collisions, secondary fragmentations,
or in disks. High mass stars form in excess of the numbers expected from pure
turbulent fragmentation as pre-stellar condensations coalesce and accrete with
an enhanced gravitational cross section. Variations in the interaction rate,
interaction strength, and accretion rate among the primary fragments formed by
turbulence lead to variations in the relative proportions of brown dwarfs,
solar to intermediate mass stars, and high mass stars.

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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: cs
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat