Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infrared spectroscopy of intermediate mass young stellar objects   In this paper we present Spitzer Infrared Spectrograph spectroscopy for 14
intermediate-mass young stellar objects. We use Spitzer spectroscopy to
investigate the physical properties of these sources and their environments.
Our sample can be divided into two types of objects: young isolated, embedded
objects with spectra that are dominated by ice and silicate absorption bands,
and more evolved objects that are dominated by extended emission from
polycyclic aromatic hydrocarbons (PAHs) and pure H2 rotational lines. We are
able to constrain the illuminating FUV fields by classifying the PAH bands
below 9micron. For most of the sources we are able to detect several atomic
fine structure lines. In particular, the [NeII] line appearing in two regions
could originate from unresolved photodissociation regions (PDRs) or J-shocks.
We relate the identified spectral features to observations obtained from NIR
through submillimeter imaging. The spatial extent of several H2 and PAH bands
is matched with morphologies identified in previous Spitzer/IRAC observations.
This also allows us to distinguish between the different H2 excitation
mechanisms. In addition, we calculate the optical extinction from the silicate
bands and use this to constrain the spectral energy distribution fit, allowing
us to estimate the masses of these YSOs.

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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol