Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatially Resolved Millimeter Spectroscopy of the Gravitational Lens PKS
  1830-211   This paper presents data from the BIMA interferometer showing spatially
resolved absorption spectra of the gravitationally lensed quasar PKS 1830-211.
High-resolution (1.2 km/s) spectra were taken in two spectral windows centered
on the redshifted frequencies of the HCO+(2-1) and HCN(2-1) molecular
transitions. There is no molecular absorption in the northeast image but the
southwest image reveals optically thick absorbing gas at these transition
frequencies. Further analyses conclude that the spectra are consistent with
completely saturated absorption in the southwest image and the line profiles
suggest that the absorbing medium is complex, perhaps containing multiple
components and small scale structure. The absorption occurs along a pencil beam
through the lensing galaxy which is thought to be a late type spiral oriented
almost face on. However, the spectra show absorption spanning more than 60 km/s
which is difficult to explain for this scenario.

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The categories of this paper are: physics
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The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org