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University of Southampton Research Repository Eprints Soton University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk UNIVERSITY OF SOUTHAMPTON The epoch and environmental dependence of radio-loud active galaxy feedback by Judith Ineson Thesis for the degree of Doctor of Philosophy in the FACULTY OF PHYSICAL SCIENCES AND ENGINEERING Department of Physics and Astronomy June 2016 UNIVERSITY OF SOUTHAMPTON ABSTRACT FACULTY OF PHYSICAL SCIENCES AND ENGINEERING Department of Physics and Astronomy Doctor of Philosophy THE EPOCH AND ENVIRONMENTAL DEPENDENCE OF RADIO-LOUD ACTIVE GALAXY FEEDBACK by Judith Ineson This thesis contains the first systematic X-ray investigation of the relationships between the properties of different types of radio-loud AGN and their large-scale environments, using samples at two distinct redshifts to isolate the effects of evolution. I used X-ray ob- servations of the galaxy clusters hosting the radio galaxies to characterise the properties of the environments and compared them with the low-frequency radio properties of the AGN. I found a strong relationship between radio luminosity and ICM richness for low- excitation radio galaxies (LERGs) but not for high-excitation radio galaxies (HERGs), and tentative evidence of evolution of the environment for HERGs, but not for LERGs. I then used the X-ray emission from the lobes of the FRII galaxies in the samples to calculate their internal pressures, finding them to be at slightly higher pressures than predicted by equipartition and near pressure balance with their external environment at the lobe mid-points. I made the first estimates of lower limits for lobe-tip Mach numbers for a large sample of lobes; suggesting that about half the lobe tips were driving strong shocks. Finally I verified that the correlation between LERG radio luminosity and cluster X-ray luminosity is not caused by a common correlation with black hole mass, and also found no evidence that HERG properties are affected by ICM richness, adding evidence for theories of local fuelling for HERGs. I found evidence that HERGs should have a strong relationship between jet power and radio luminosity, but that LERG jet power must be subject to factors additional to black hole mass. I also found evidence that the same mass black hole is associated with lower radio luminosities in FRI morphology galaxies than in FRIIs, perhaps as a result of the higher proton content of FRI jets leading to lower radiative efficiency. Contents Abstract iii List of Contents iv List of Figures ix List of Tables xi Declaration of Authorship xiii Acknowledgements xiv 1 Introduction 1 1.1 Radio galaxies ................................. 1 1.1.1 General ................................. 1 1.1.2 Types of radio galaxy ......................... 5 1.1.2.1 Morphological classification ................. 5 1.1.2.2 Emission processes ...................... 7 1.1.2.3 Spectral classification .................... 14 1.1.2.4 Accretion physics ...................... 18 1.1.2.5 HERG and LERG accretion modes ............ 19 1.2 Galaxy groups and clusters .......................... 21 1.2.1 Galaxy content ............................. 21 1.2.2 Intra-cluster medium .......................... 23 1.3 Radio galaxy interactions with the environment ............... 27 1.3.1 The environments of radio-loud AGN ................ 28 1.3.2 Difficulties ................................ 30 1.3.3 Lobe interactions with the ICM .................... 31 1.3.3.1 Particle content ....................... 33 1.3.3.2 Filling factor ......................... 34 1.4 Thesis aims ................................... 34 2 Instrumental details and data analysis 37 2.1 Instrumental details .............................. 37 2.1.1 X-ray telescopes ............................ 37 v Contents vi 2.1.1.1 Chandra ........................... 38 2.1.1.2 XMM-Newton ........................ 38 2.1.1.3 Telescope compatibility ................... 40 2.1.2 Radio telescopes ............................ 42 2.2 Data analysis .................................. 43 2.2.1 Data preparation for the X-ray observations ............. 43 2.2.1.1 Calibrations ......................... 43 2.2.1.2 Particle background and flares ............... 44 2.2.1.3 Pile-up ............................ 45 2.2.1.4 External X-ray background ................. 45 2.2.1.5 Removal of extraneous emission .............. 46 2.2.2 Spatial analysis ............................. 46 2.2.3 ICM spectral analysis ......................... 51 2.2.3.1 Single subtraction, source background ........... 52 2.2.3.2 Single subtraction, blank sky background ......... 53 2.2.3.3 Double subtraction ..................... 53 2.2.3.4 Temperature estimates ................... 54 2.2.3.5 FRII lobe X-ray flux ..................... 55 2.2.4 FRII lobe fields and pressures ..................... 55 2.2.5 FRII lobe Mach numbers ....................... 56 2.3 Summary .................................... 56 3 Environments of radio-loud AGN at redshift 0.5 59 3.1 Introduction ................................... 59 3.2 The sample ................................... 60 3.3 Observations and data preparation ...................... 62 3.3.1 X-ray data ............................... 62 3.3.2 Radio data ............................... 62 3.4 Analysis ..................................... 63 3.4.1 Imaging ................................. 63 3.4.2 Spatial analysis ............................. 64 3.4.3 Spectral analysis ............................ 66 3.5 Results and discussion ............................. 66 3.5.1 Radio galaxy environments ...................... 66 3.5.2 Comparison with general cluster environments ........... 68 3.5.3 Comparison with optical measures .................. 70 3.5.4 Implications ............................... 72 3.6 Conclusions ................................... 74 3.7 Images and surface brightness profiles .................... 75 4 Environments at redshift 0.1, and environment evolution 91 4.1 Introduction ................................... 91 4.2 The sample ................................... 92 4.3 Observations and data preparation ...................... 93 4.3.1 X-ray data ............................... 93 4.3.2 Radio data ............................... 94 4.4 Analysis ..................................... 94 Contents vii 4.4.1 Spatial analysis ............................. 94 4.4.2 Spectral analysis ............................ 98 4.5 Results and discussion ............................. 99 4.5.1 Radio galaxy environments ...................... 99 4.5.1.1 z0.1 sample results ...................... 99 4.5.1.2 Combined z0.1 and ERA samples .............100 4.5.1.3 Redshift evolution ......................101 4.5.1.4 Cluster morphology .....................102 4.5.1.5 Central density ........................103 4.5.2 Comparison with general cluster and group environments . 104 4.5.3 Comparison with optical measures ..................108 4.5.4 Implications ...............................108 4.5.4.1 LERG results .........................109 4.5.4.2 HERG results ........................109 4.6 Conclusions ...................................110 4.7 Notes on the z0.1 sources ...........................111 4.7.1 3CRR sources ..............................112 4.7.2 2Jy sources ...............................122 5 FRII galaxy lobes and the intra-cluster medium 145 5.1 Introduction ...................................145 5.2 Sample ......................................146 5.3 Analysis .....................................147 5.4 Results and discussion .............................149 5.4.1 Deviation from equipartition .....................149 5.4.2 Lobe pressure balance .........................149 5.4.3 Lobe tip Mach number .........................151 5.4.4 Systematic errors ............................155 5.4.4.1 Lobe volumes .........................155 5.4.4.2 Low frequency spectral index ................156 5.4.4.3 Maximum and minimum energies .............156 5.4.4.4 Radio observation properties ................157 5.4.4.5 Lobe viewing angle .....................157 5.4.4.6 Excluded lobes ........................158 5.4.4.7 Environment measurements .................159 5.4.4.8 Overall effect of systematics ................160 5.4.5 Implications ...............................160 5.5 Conclusions ...................................161 6 AGN central properties and the cluster environment 169 6.1 Introduction ...................................169 6.2 Sample ......................................170 6.3 Black hole mass .................................173 6.3.1 3.4 µm magnitude and redshift ....................173 6.3.2 3.4 µm and radio luminosities .....................175 6.3.3 3.4 µm and ICM luminosities .....................177 6.4 Accretion rate ..................................179 Contents viii
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