Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The relationship between Mg II broad emission and quasar inclination
  angle   Several observed spectral properties of quasars are believed to be influenced
by quasar orientation. In this investigation we examine the effect of
orientation on the Mg II line located at 2798 {\AA} in a sample of 36
radio-loud quasars, with orientation angles having been obtained in a previous
study using radio observations. We find no significant relationship between
orientation angle and either Mg II line full-width at half-maximum or
equivalent width. The lack of correlation with inclination angle contradicts
previous studies which also use radio data as a proxy for inclination angle and
suggests the Mg II emission region does not occupy a disk-like geometry. The
lack of correlation with Mg II equivalent width, however, is reported in at
least one previous study. Although the significance is not very strong (86
percent), there is a possible negative relationship between inclination angle
and Fe II strength which, if true, could explain the Fe II anti-correlation
with [O III ] strength associated with Eigenvector 1. Interestingly, there are
objects having almost edge-on inclinations while still exhibiting broad lines.
This could be explained by a torus which is either clumpy (allowing sight lines
to the central engine) or mis-aligned with the accretion disk.

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The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
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The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat