Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Herschel study of YSO evolutionary stages and formation timelines in
  two fields of the Hi-GAL survey   We present a first study of the star-forming compact dust condensations
revealed by Herschel in the two 2 \times 2 \degr Galactic Plane fields centered
at [l;b] = [30\degr; 0 \degr] and [l;b] = [59\degr; 0 \degr], respectively, and
observed during the Science Demonstration Phase for the Herschel infrared
Galactic Plane survey (Hi-GAL) Key-Project. Compact source catalogs extracted
for the two fields in the five Hi-GAL bands (70, 160, 250, 350 and 500 $\mu$m)
were merged based on simple criteria of positional association and spectral
energy distribution (SED) consistency into a final catalog which contains only
coherent SEDs with counterparts in at least three adjacent Herschel bands.
These final source lists contain 528 entries for the l = 30\degr field, and 444
entries for the l = 59\degr field. The SED coverage has been augmented with
ancillary data at 24 $\mu$m and 1.1 mm. SED modeling for the subset of 318 and
101 sources (in the two fields, respectively) for which the distance is known
was carried out using both a structured star/disk/envelope radiative transfer
model and a simple isothermal grey-body. Global parameters like mass,
luminosity, temperature and dust properties have been estimated. The Lbol/Menv
ratio spans four orders of magnitudes from values compatible with the
pre-protostellar phase to embedded massive zero-age main sequence stars.
Sources in the l = 59\degr field have on average lower L/M, possibly outlining
an overall earlier evolutionary stage with respect to the sources in the l =
30\degr field. Many of these cores are actively forming high-mass stars,
although the estimated core surface densities appear to be an order of
magnitude below the 1 g cm$^{-2}$ critical threshold for high-mass star
formation.

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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
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The categories of this paper are: cs
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: q-bio