Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The environment of low redshift quasar pairs   We investigate the properties of the galaxy environment of a sample of 14 low
redshift (z $<$ 0.85) quasar physical pairs extracted from SDSS DR10 archives.
The pairs have a systemic radial velocity difference $\Delta V_\parallel
\leqslant$ 600 $km \ s^{-1}$ (based on [OIII]5007 \AA \ line) and projected
distance $ R_\bot \leqslant$ 600 kpc. The physical association of the pairs is
statistically confirmed at a level of $\sim$ 90 %. For most of the images of
these quasars we are able to resolve their host galaxies that turn out to be on
average similar to those of quasars not in pairs. We also found that quasars in
a pair are on average in region of modest galaxy overdensity extending up 0.5
Mpc from the QSO. This galaxy overdensity is indistinguishable from that of a
homogeneous sample of isolated quasars at the same redshift and with similar
host galaxy luminosity. These results, albeit derived from a small (but
homogeneous) sample of objects, suggest that the rare activation of two quasars
with small physical separation does not require any extraordinary environment.

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The categories of this paper are: physics
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: nlin
28
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: bayes-an
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn