Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of Low z Absorbers in the QSO Spectra   We present the results of reanalysis of low z Mg II absorption line sample
compiled by SS92. The conditions on cloud parameters to produce N(Fe II)>N(Mg
II) are obtained using photoionization models and curve of growth. Properties
of Mg II absorbers with W(Fe II)/W(MgII) (definded as R) >and< 0.5 are analysed
separately. Contrary to the whole Mg II sample, the clouds with R<0.5 show a
steep increase in number density (N(z)) with z. These systems also show clear
increase in W(Mg II) and doublet ratio(dr) of Mg II with z. However there is no
correlation between W(Mg II) and dr. In the case of R>0.5 clouds W(Mg II) and
dr are not correlated with z. However there is a clear anticorrelation between
dr and W(Mg II). We find a clear decrease in the ratio of W(Fe II) and W(Mg II)
with z. The N(z) as well as average N(Fe II) of Fe II lines selected absorbers
are not evolving with z. The available data of LLS, are not showing any
dependence of (tau_{LLS}) on z. We collected the LLS information for 53 QSO
sight lines, for which details of Mg II absorption are available. There are 4
Mg II absorption systems which are not LLS at z which are lower than the mean z
of the sample (z=1.1). In the higher z, where one expect to see 2.5\pm1.4 such
absorbers, we do not find any nonLLS Mg II absorbers. Individual systems with
tau_{LLS}<3.0 are analysed. Our results imply some of the absorbers at z=0.6
have reached metallicity roughly around solar value. The required ionization
parameters for these systems are less than 0.001 in most cases. Our results
together with results obtained for high z absorbers confirm that mean
ionization state of metal rich absorbing clouds falls with z.

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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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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: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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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: q-bio
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The categories of this paper are: adap-org