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Quasar evolution: black hole mass and accretion rate determination

Published online by Cambridge University Press:  01 August 2006

Deborah Dultzin-Hacyan ,
Paola Marziani ,
C. Alenka Negrete  and
Jack W. Sulentic
Deborah Dultzin-Hacyan
Affiliation:
Instituto de Astronomía, UNAM, Apdo. Postal 70-264, 04510 Mexico D.F., Mexico email: deborah@astroscu.unam.mx
Paola Marziani
Affiliation:
INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italypaola.marziani@oapd.inaf.it
C. Alenka Negrete
Affiliation:
Instituto de Astronomía, UNAM, Apdo. Postal 70-264, 04510 Mexico D.F., Mexico email: deborah@astroscu.unam.mx
Jack W. Sulentic
Affiliation:
Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USAgiacomo@merlot.astr.ua.edu
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Abstract

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Accurate measurements of emission line properties are crucial to understand the physics of the broad line region in quasars. This region consists of warm gas that is closest to the quasar central engine and has not been spatially resolved for almost all sources. We present here an analysis of optical and IR data for a large sample of quasars, covering the Hi Hβ spectral region in the redshift range 0 ≲ z ≲ 2.5. Spectra were interpreted within the framework of the the so-called “eigenvector 1” parameter space, which can be viewed as a tentative H-R diagram for quasars. We stress the lack of spectral evolution in the low ionization lines of quasars, with prominent Fe ii emission also at z ≳ 2. We also show how selection effects influence the ability to find quasars radiating at low Eddington ratio in flux-limited surveys. The quasar similarity at different redshift is probably due to the absence of super-Eddington radiators (at least within the caveats of black hole mass and Eddington ratio determination discussed in this paper) as well as to the limited Eddington ratio range within which quasars seem to radiate.

Keywords

Quasars: general – quasars: emission lines
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 2 , Symposium S238: Black Holes from Stars to Galaxies – Across the Range of Masses , August 2006 , pp. 83 - 86
Copyright
Copyright © International Astronomical Union 2007

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