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The Environments of Optically-Selected QSOs

Published online by Cambridge University Press:  03 August 2017

B. J. Boyle
Affiliation:
Department of Astronomy, University of Edinburgh, U.K.
T. Shanks
Affiliation:
Department of Physics, University of Durham, U.K.
H. Yee
Affiliation:
Department of Physics, University of Montreal, Canada

Extract

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In recent years much attention has been focussed on the environments of low redshift QSOs. In particular, Yee and Green (1987) have found that the average environment of radio-loud QSOs at z ≃ 0.6, as measured by the QSO-galaxy spatial covarience function, is over three times richer than that of radio-loud QSOs at z ≃ 0.4. This strongly indicates that there has been a steep evolution in the numbers of QSOs in rich clusters over a period of 109 years. This observation is therefore inconsistent with pure luminosity evolution models, which preserves QSO number with epoch, currently employed by a number of authors (see e.g. Boyle et al. 1987) to explain the observed redshift dependence of the QSO luminosity function. However, since over 90% of QSOs are radio-quiet, the main test concerning the validity of pure luminosity evolution is to look for similar evolutionary effects in the preferred environments of optically-selected QSOs.

Type
Appendix 1: Poster Papers
Copyright
Copyright © Reidel 1988 

References

Boyle, B.J., Fong, R., Shanks, T. and Peterson, B.A. 1987, MNRAS, in the press.Google Scholar
Yee, H.K.C. and Green, R.F. 1987, Ap. J., in the press.Google Scholar