Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of OH and wide HI absorption toward B0218+357   We present deep GMRT OH and WSRT HI absorption spectra of the $z = 0.6846$
gravitational lens toward B0218+357. Both the 1665 MHz and 1667 MHz OH lines
are clearly detected for the first time while a new wide absorption component
was detected (at low significance) in the HI spectrum; the OH spectra yielded
an OH column density of $N_{OH} = 2.3 \times 10^{15}$ cm^{-2}. The ratio of
1667 and 1665 MHz equivalent widths is $\sim 1.8$ while the redshift of peak OH
absorption is $z = 0.68468 \pm 0.000008$ for both lines; this redshift agrees
with that obtained from the HI line. The velocity spread (between nulls) of the
HI absorption is $\sim 140$ km/s, while that of both OH lines is $\sim 100$
km/s; the HI and OH spectra are broadly similar in that they each have two
principal narrow components and a wide absorption trough. We argue that the
wide absorption is likely to arise from source components in the Einstein ring
and derive a rotation velocity of $\sim 150$ km/s at a distance of 1.5 kpc from
the centre of the $z \sim 0.6846$ galaxy.

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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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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: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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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: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn