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Title: The cosmological evolution of supermassive black holes
Author: Yi, Qiang
ISNI:       0000 0004 2728 1148
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2011
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In this thesis we investigate selection effects in astrophysical observations. We demonstrate that the determination of the quasar black hole mass function and Eddington ratio distribution via observations are biased. By modelling the quasar selection function and the black hole mass measurement process we show that one is able to infer the true distribution of physical quantities from observations. We present the intrinsic accretion rates of AGN, the intrinsic accretion rates and the black hole mass function for optically selected quasars up to redshift of two. The results show that the Eddington limit continues to be a real physical limit to black hole accretion. We present a new upper limit of black hole masses from the inferred intrinsic black hole mass function and demonstrate the need of a mass dependent accretion rate in accordance with down sizing. Finally we investigate correlations between radio luminosity and observed black hole mass for optically selected quasars. We first show that mixing of fiat and steep spectrum quasars leads to results that are dependent on the observing frequency, and therefore should be treated with caution. We demonstrate that beaming of the radio core together with an orientation dependent optical selection effect can give rise to a bimodal distribution in the radio luminosities of optically selected quasars.
Supervisor: Miller, Lance Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Black holes (Astronomy) ; Dark matter (Astronomy) ; Galaxies