Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Super-Solar Metallicity in Weak Mg II Absorption Systems at z ~ 1.7   Through photoionization modeling, constraints on the physical conditions of
three z ~ 1.7 single-cloud weak Mg II systems (W_r(2796) < 0.3A) are derived.
Constraints are provided by high resolution R = 45,000, high signal-to-noise
spectra of the three quasars HE0141-3932, HE0429-4091, and HE2243-6031 which we
have obtained from the ESO archive of VLT/UVES. Results are as follows:
  (1) The single-cloud weak Mg II absorption in the three z ~ 1.7 systems is
produced by clouds with ionization parameters of -3.8 < logU < -2.0 and sizes
of 1-100 pc.
  (2) In addition to the low-ionization phase Mg II clouds, all systems need an
additional 1-3 high-ionization phase C IV clouds within 100 km/s of the Mg II
component. The ionization parameters of the C IV phases range from -1.9 < logU
< -1.0, with sizes of tens of parsecs to kiloparsecs.
  (3) Two of the three single-cloud weak Mg II absorbers have near-solar or
super-solar metallicities, if we assume a solar abundance pattern. Although
such large metallicities have been found for z < 1 weak Mg II absorbers, these
are the first high metallicities derived for such systems at higher redshifts.
  (4) Two of the three weak Mg II systems also need additional low-metallicity,
broad Lya absorption lines, offset in velocity from the metal-line absorption,
in order to reproduce the full Lya profile.
  (5) Metallicity in single-cloud weak Mg II systems are more than an order of
magnitude larger than those in Damped Lya systems at z ~ 1.7. In fact, there
appears to be a gradual decrease in metallicity with increasing N(HI), from
these, the most metal-rich Lya forest clouds, to Lyman limit systems, to
sub-DLAs, and finally to the DLAs.

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The categories of this paper are: stat
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The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: cs
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int