Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A CS J=5-4 Mapping Survey Towards High-mass Star Forming Cores
  Associated with Water Masers   We have mapped 63 regions forming high-mass stars in CS J=5-4 using the CSO.
The CS peak position was observed in C34S J=5-4 towards 57 cores and in 13CS
J=5-4 towards the 9 brightest cores. The sample is a subset of a sample
originally selected toward water masers; the selection on maser sources should
favor sources in an early stage of evolution. The integrated intensity of CS
J=5-4 correlates very well with the dust continuum emission at 350 microns. The
distributions of size, virial mass, surface density, and luminosity are all
peaked with a few cores skewed towards much larger values than the mean. We
find a weak correlation between C34S linewidth and size, consistent with Dv ~
R^{0.3}. The linewidths are much higher than would be predicted by the usual
relations between linewidth and size determined from regions of lower mass.
These regions are very turbulent. The derived virial mass agrees within a
factor of 2 to 3 with mass estimates from dust emission at 350 microns after
corrections for the density structure are accounted for. The resulting
cumulative mass spectrum of cores above 1000 solar masses can be approximated
by a power law with a slope of about -0.9, steeper than that of clouds measured
with tracers of lower density gas and close to that for the total masses of
stars in OB associations. The median turbulent pressures are comparable to
those in UCHII regions, and the pressures at small radii are similar to those
in hypercompact-HII regions (P/k ~ 10^{10} K cm^{-3}). The filling factors for
dense gas are substantial, and the median abundance of CS is about 10^{-9}. The
ratio of bolometric luminosity to virial mass is much higher than the value
found for molecular clouds as a whole, and the correlation of luminosity with
mass is tighter. (Abridged).

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The categories of this paper are: cond-mat
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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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: nlin
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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph