Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Oxygen lines in solar granulation. I. Testing 3D models against new
  observations with high spatial and spectral resolution   Aims: we seek to provide additional tests of the line formation of
theoretical 3D solar photosphere models. In particular, we set out to test the
spatially-resolved line formation at several viewing angles, from the solar
disk-centre to the limb and focusing on atomic oxygen lines. The purpose of
these tests is to provide additional information on whether the 3D model is
suitable to derive the solar oxygen abundance. We also aim to empirically
constrain the NLTE recipes for neutral hydrogen collisions, using the
spatially-resolved observations of the OI 777 nm lines. Methods: using the
Swedish 1-m Solar Telescope we obtained high-spatial-resolution observations of
five atomic oxygen lines (along with lines for other species) for five
positions on the solar disk. These observations have a high spatial and
spectral resolution, and a continuum intensity contrast up to 9% at 615 nm. The
theoretical line profiles were computed using the 3D model, with a full 3D NLTE
treatment for oxygen and LTE for the other lines. Results: at disk-centre we
find an excellent agreement between predicted and observed line shifts,
strengths, FWHM and asymmetries. At other viewing angles the agreement is also
good, but the smaller continuum intensity contrast makes a quantitative
comparison harder. We use the disk-centre observations we constrain S_H, the
scaling factor for the efficiency of collisions with neutral hydrogen. We find
that S_H=1 provides the best match to the observations. Conclusions: overall
there is a very good agreement between predicted and observed line properties
over the solar granulation. This further reinforces the view that the 3D model
is realistic and a reliable tool to derive the solar oxygen abundance.

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The categories of this paper are: patt-sol
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
7
The categories of this paper are: hep-th