Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Determination of astrophysical parameters of quasars within the Gaia
  mission   We describe methods designed to determine the astrophysical parameters of
quasars based on spectra coming from the red and blue spectrophotometers of the
Gaia satellite. These methods principally rely on two already published
algorithms that are the weighted principal component analysis and the weighted
phase correlation. The presented approach benefits from a fast implementation;
an intuitive interpretation as well as strong diagnostic tools on the potential
errors that may arise during predictions. The production of a semi-empirical
library of spectra as they will be observed by Gaia is also covered and
subsequently used for validation purpose. We detail the pre-processing that is
necessary in order for these spectra to be fully exploitable by our algorithms
along with the procedures that are used in order to predict the redshifts of
the quasars; their continuum slopes; the total equivalent width of their
emission lines and whether these are broad absorption line (BAL) quasars or
not. Performances of these procedures were assessed in comparison with the
Extremely Randomized Trees learning method and were proven to provide better
results on the redshift predictions and on the ratio of correctly classified
observations though the probability of detection of BAL quasars remains
restricted by the low resolution of these spectra as well as by their limited
signal-to-noise ratio. Finally, the triggering of some warning flags allows us
to obtain an extremely pure subset of redshift predictions where approximately
99% of the observations come along with absolute errors that are below 0.1.

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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
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The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ