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Paper: Eigenvector 1: The Future HR Diagram for AGNs?
Volume: 360, AGN Variability from X-Rays to Radio Waves
Page: 281
Authors: Kajdic, P.; Dultzin-Hacyan, D.; Sulentic, J.W.; Marziani, P.
Abstract: High-quality spectra show striking differences among different types of active galactic nuclei (AGNs). Obvious differences appear between the radio-loud and radio-quiet sources and also between high and low ionization lines. A correlation space called Eigenvector 1 (E1) seems to optimally discriminate among different types of AGNs that show broad emission lines in their spectra, although the orientation of the sources interferes strongly with E1 parameters. Different surveys of quasar spectra made by our group in the past, which present the basis for E1, were selected on the basis of UV excess, which also implies an excess in soft X-rays. This could produce false correlations in the E1 correlation space. Just recently we have started a new survey for which we selected the objects from the Hamburg Quasar Survey and Hamburg/ESO Survey for Bright Quasars. These objects are not biased, so they will give us independent information on the distribution of AGNs in E1.
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