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X-ray observations of high redshift active galactic nuclei and galaxy clusters

Waskett, Timothy 2004. X-ray observations of high redshift active galactic nuclei and galaxy clusters. PhD Thesis, Cardiff University.

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X-ray surveys of three Canada-France Redshift Survey (CFRS) fields using XMM-Newton are presented, with the aim of studying the Active Galactic Nuclei (AGN) and galaxy cluster populations in these fields. The X-ray sources detected in these surveys resolve 51% of the X-ray background (XRB) in the 0.5 10 keV X-ray band. The relation between the X-ray and sub-mm extra-galactic backgrounds is investigated using a combination of X-ray data and sub-mm data. The X-ray properties of the sub-mm sources and visa versa indicate that the XRB is domi nated by accretion onto super-massive black holes, while the sub-mm background is dominated by dust-obscured star formation. X-ray sources are identified with optical objects using the Canada-France Deep Fields (CFDF) survey, which covers the majority of two fields. The redshift dis tribution of the AGN shows a clear peak at z 0.7. The 2-point angular correlation function, W(6), is calculated for the identified AGN but no significant clustering is detected. However, the results are consis tent with X-ray selected AGN being good tracers of the normal, inactive galaxy population. The environments of moderate luminosity AGN at z 0.5 are investigated, using the clustering amplitude measure Bgq and close pair counts. When compared to a control sample of equivalent inactive galaxies no difference is found between the respective environments. Minor mergers with low mass companions is therefore the most likely mechanism by which these AGN are fuelled. A new method for finding high redshift, optically selected, galaxy clusters is presented and is compared to X-ray selection. It is found that most optically selected clusters may have lower than expected X-ray luminosities suggesting that they are dynamically young compared to X-ray selected clusters.

Item Type: Thesis (PhD)
Status: Unpublished
Schools: Physics and Astronomy
Subjects: Q Science > QC Physics
ISBN: 9781303200366
Date of First Compliant Deposit: 30 March 2016
Last Modified: 12 Feb 2016 23:15

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