Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mid-infrared interferometry of the massive young stellar object NGC 2264
  IRS 1   The optically invisible infrared-source NGC 2264 IRS 1 is thought to be a
massive young stellar object (~10 Msun). Although strong infrared excess
clearly shows that the central object is surrounded by large amounts of
circumstellar material, no information about the spatial distribution of this
circumstellar material has been available until now. We used the ESO Very Large
Telescope Interferometer to perform long-baseline interferometric observations
of NGC 2264 IRS 1 in the mid-infrared regime. Our observations resolve the
circumstellar material around NGC 2264 IRS 1, provide the first direct
measurement of the angular size of the mid-infrared emission, and yield direct
constraints on the spatial distribution of the dust. We use different
approaches (a geometrical model, a temperature-gradient model, and radiative
transfer models) to jointly model the observed interferometric visibilities and
the spectral energy distribution. The derived visibility values between ~0.02
and ~0.3 show that the mid-infrared emission is clearly resolved. The
characteristic size of the MIR-emission region is ~30-60 AU; this value is
typical for other YSOs with similar or somewhat lower luminosities. A
comparison of the sizes for the two position angles shows a significant
elongation of the dust distribution. Simple spherical envelope models are
therefore inconsistent with the data. The radiative transfer modeling of our
data suggests that we observe a geometrically thin and optically thick
circumstellar disk with a mass of about 0.1 Msun. Our modeling indicates that
NGC 2264 IRS 1 is surrounded by a flat circumstellar disk that has properties
similar to disks typically found around lower-mass young stellar objects. This
result supports the assumption that massive young stellar objects form via
accretion from circumstellar disks.

7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph