Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing 3-D matter distribution at z~2 with QSO multiple lines of sight   We investigate the 3-D matter distribution at z~2 with high resolution (R ~
40000) spectra of QSO pairs and groups obtained with the UVES spectrograph at
ESO VLT. Our sample is unique for the number density of objects and the variety
of separations, between 0.5 and 7 proper Mpc. We compute the real space
cross-correlation function of the Lyman-alpha forest transmitted fluxes. There
is a significant clustering signal up to ~2 proper Mpc, which is still present
when absorption lines with high column density (log N > 13.8) are excluded.

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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: plasm-ph
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: funct-an