Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffuse Far-ultraviolet Observations of the Taurus Region   Diffuse far-ultraviolet (FUV: 1370-1670 A) flux from the Taurus molecular
cloud region has been observed with the SPEAR/FIMS imaging spectrograph. An FUV
continuum map of the Taurus region, similar to the visual extinction maps,
shows a distinct cloud core and halo region. The dense cloud core, where the
visual extinction is A_v > 1.5, obscures the background diffuse FUV radiation,
while a scattered FUV radiation is seen in and beyond the halo region where A_v
< 1.5. The total intensity of H2 fluorescence in the cloud halo is I_{H2} = 6.5
x 10^4 photons cm^{-2} s^{-1} sr^{-1} in the 1370-1670 A wavelength band. A
synthetic model of the H2 fluorescent emission fits the present observation
best with a hydrogen density n_H = 50 cm^{-3}, H2 column density N(H2) = 0.8 x
10^{20} cm^{-2}, and an incident FUV intensity I_{UV} = 0.2. H2 fluorescence is
not seen in the core presumably because the required radiation flux to induce
fluorescence is unable to penetrate the core region.

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The categories of this paper are: quant-ph
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The categories of this paper are: nlin
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
16
The categories of this paper are: stat
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con