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The Evolution of QSO Spectra: Evidence for Microlensing?

Published online by Cambridge University Press:  25 May 2016

Paul J. Francis  and
Anuradha Koratkar
Paul J. Francis
Affiliation:
School of Physics, University of Melbourne Parkville, Victoria 3054, Australia E-mail: pjf@physics.unimelb.edu.au
Anuradha Koratkar
Affiliation:
Space Telescope Science Institute 3700 San Martin Drive, Baltimore, MD 21218, USA E-mail: koratkar@stsci.edu

Abstract

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We find that the spectra of QSOs evolve: high redshift QSOs (z > 1.5) have lower equivalent width emission lines than low redshift QSOs (z < 0.5) with the same luminosities and radio properties.

We propose that microlensing by compact objects may account for the apparent evolution. If Ω ∼ 0.05 in compact objects, the continuum emission from many high redshift QSOs will be amplified, but not the line emission, leading to the observed decrease in the apparent equivalent widths.

Type
Chapter 8: Quasar Structure & Microlensing
Information
Symposium - International Astronomical Union , Volume 173: Astrophysical Applications of Gravitational Lensing , 1996 , pp. 289 - 290
Copyright
Copyright © Kluwer 1996 

References

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