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تسجيل مستخدم جديدEigenspectra of the SDSS DR1 quasars
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We construct eigenspectra from the DR1 quasars in the SDSS using the Karhunen-Lo`eve (KL) transform (or Principal Component Analysis, PCA) in different redshift and luminosity bins. We find that the quasar spectra can be classified, by the first two eigenspectra, into a continuous sequence in the variation of the spectral slope. We also find a dependence on redshift and luminosity in the eigencoefficients. The dominant redshift effect is the evolution of the blended Fe~II emission (optical) and the Balmer continuum (the ``small-bump, $lambda_{rest} approx 2000-4000$AA), while the luminosity effect is related to the Baldwin effect. Correlations among several major broad emission lines are found, including the well-known ``Eigenvector-1.
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