Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ISO Mid-Infrared Spectra of Reflection Nebulae   We present 5-15 micron imaging spectroscopy of the reflection nebulae vdB 17
(NGC 1333), vdB 59 (NGC 2068), vdB 101, vdB 111, vdB 133 and vdB 135, obtained
with the infrared camera and circular variable filter wheel on the Infrared
Space Observatory (ISO). These nebulae are illuminated by stars with Teff =
3,600-19,000 K, implying ultraviolet to total stellar flux ratios of F(< 400
nm)/F(tot) = 0.01-0.87. We detect the infrared emission features (IEFs) at 6.2,
7.7, 8.6, 11.3, and 12.7 microns, broad emission features at 6-9 microns and
11-13 microns, and 5-15 micron continuum emission, from the interstellar medium
in vdB 17, vdB 59, and vdB 133 (F(< 400 nm)/F(tot) = 0.22-0.87), and place
upper limits on the emission from the interstellar medium in vdB 101, vdB 111,
and vdB 135 (F(< 400 nm)/F(tot) = 0.01-0.20).
  We observe no spectroscopic differences with varying Teff. We analyze the
spectra of vdB 17 and vdB 59 as a function of distance from the star to see how
the spectra depend on Go within each source. The only quantitative difference
we find is a broadening of the 7.7 micron IEF at Go = 20-60 within vdB 17. We
observe only a 40% change in the 6-10 micron to 10-14 micron flux ratio over Go
= 20 to 60,000.

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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat