Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hubble Space Telescope Measurements of Vacuum Ultraviolet Lines of
  Interstellar CH   Three interstellar absorption lines near 1370 A seen toward zeta Oph have
been assigned by Watson to Rydberg transitions in the G-X (or 3d-X) band of CH.
Our survey of a dozen diffuse interstellar lines of sight shows that the three
absorption lines are consistent with the known column densities of CH, by
deriving the following oscillator strengths: f(1368.74) = 0.019 +/- 0.003,
f(1369.13) = 0.030 +/- 0.005, and f(1370.87) = 0.009 +/- 0.001. We also
determined intrinsic line widths that correspond to decay rates of (1.5 +/-
0.6) x 10^11 s^-1, (3.8 +/- 0.7) x 10^11 s^-1, and (1.1 +/- 0.6) x 10^10 s^-1
for lambdalambda 1368, 1369, and 1370, respectively. These rates are
significantly higher than those associated with radiative decays, and thus are
readily attributable to predissociation of the Rydberg state. A fourth
interstellar line near 1271 A has been conjectured by Watson to be the
strongest transition in the 4d-X Rydberg band of CH. We detected this line
along four sight lines and our spectrum syntheses show that with f(1271.02) =
0.007 +/- 0.002, it is also consistent with the known column densities of CH.
In addition, we conducted a search for the F-X band of CH near 1549 A, and
successfully discovered two of its absorption features along four sight lines.
The astronomical oscillator strengths derived for these features are f(1549.05)
= 0.021 +/- 0.006 and f(1549.62) = 0.013 +/- 0.003. Finally, the X Per sight
line provided us with an astronomical detection of another CH band, via two D-X
features near 1694 A. Comparisons with results of available theoretical
calculations for the four CH bands are presented.

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The categories of this paper are: eess
7
The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con