Radio galaxies and quasars are among the largest and most powerful single objects known and are believed to have had a significant impact on the evolving Universe and its large scale structure. Their jets inject a significant amount of energy into the surrounding medium, hence they can provide useful information in the study of the density and evolution of the intergalactic and intracluster medium. The jet activity is also believed to regulate the growth of massive galaxies via the AGN feedback. In this thesis I explore the intrinsic and extrinsic physical properties of the population of Fanaroff-Riley II (FR II) objects, i.e. their kinetic luminosities, lifetimes, and central densities of their environments. In particular, the radio and kinetic luminosity functions of these powerful radio sources are investigated using the complete, flux limited radio catalogues of 3CRR and BRL. I construct multidimensional Monte Carlo simulations using semi-analytical models of FR II source time evolution to create artificial samples of radio galaxies. Unlike previous studies, I compare radio luminosity functions found with both the observed and simulated data to explore the best-fitting fundamental source parameters. The Monte Carlo method presented here allows one to: (i) set better limits on the predicted fundamental parameters of which confidence intervals estimated over broad ranges are presented, and (ii) generate the most plausible underlying parent populations of these radio sources. Moreover, I allow the source physical properties to co-evolve with redshift, and I find that all the investigated parameters most likely undergo cosmological evolution; however these parameters are strongly degenerate, and independent constraints are necessary to draw more precise conclusions. Furthermore, since it has been suggested that low luminosity FR IIs may be distinct from their powerful equivalents, I attempt to investigate fundamental properties of a sample of low redshift, low radio luminosity density radio galaxies. Based on SDSS-FIRST-NVSS radio sample I construct a low frequency (325 MHz) sample of radio galaxies and attempt to explore the fundamental properties of these low luminosity radio sources. The results are discussed through comparison with the results from the powerful radio sources of the 3CRR and BRL samples. Finally, I investigate the total power injected by populations of these powerful radio sources at various cosmological epochs and discuss the significance of the impact of these sources on the evolving Universe. Remarkably, sets of two degenerate fundamental parameters, the kinetic luminosity and maximum lifetimes of radio sources, despite the degeneracy provide particularly robust estimates of the total power produced by FR IIs during their lifetimes. This can be also used for robust estimations of the quenching of the cooling flows in cluster of galaxies.

A custom made five panel filter mosaic window was designed, installed and operated with the HiTIES (High Throughput Imaging Echelle Spectrograph) at the Nordlysstasjonen in Svalbard, Norway (78.2025N and 15.829E). The filter provides images of the resonant scattered spectra of N+ 2 1N (0,1), (1,2), (2,3) bands and a neutral N2 2P (0,3) band. Ab initio models were created for describing the populations of vibrational and rotational energy levels in both excited and ionised N2 molecules in the ionosphere. In the rotational profiles the species are treated to be in thermal equilibrium, whereas the vibrational levels assume a non-thermal steady state time independent model. Rotational temperatures were evaluated for different auroral forms for the N+ 2 (0,2) band from the magnetic zenith and along the meridian slit in HiTIES data from winter. A clear trend in neutral temperature is found, with higher values for times of lower energy precipitation. The relationship between resonant scattering of solar photons via N+ 2 and direct emission from electron impact on N2 was evaluated qualitatively and quantitatively with HiTIES data from January-March 2007. A relationship was found that clearly indicates the emission profiles are a function of primary electron energy and solar shadow height when auroral arcs are partially sunlit during events of electron precipitation.

High Mass X-ray Binaries (HMXBs) represent an important stage in the evolution of massive stars and are some of the brightest sources in the X-ray sky. In the first half of this thesis a detailed analysis of X-ray observations of two HMXBs, the Be/X-ray Binary (BeXRB) Swift J045106.8-694803 and the supergiant/X-ray Binary XTE J0421+560/CI Camelopardalis, is presented. Simulations of the X-ray spectrum of Swift J045106.8-694803 show that both the spectral and timing properties can be reproduced by a blackbody and power law pulsating ∼ pi out of phase with each other. The pulse profile of the blackbody is used to determine the angle between the rotation and magnetic axes of the neutron star and the angle between the rotation axis and line of sight. The apparently broad iron line of XTE J0421+560 is decomposed into three intrinsically narrow lines, FeI-Ka, FeIK b and FeXXIV-XXVKa. The light curve extracted in the energy range defined as the Fe-Ka line from the spectral fits shows marginal evidence for a lag when cross correlated with that of the continuum. The lag is interpreted as the light crossing time of the circumbinary torus and implies a radius of 10 AU. The second part of this thesis considers HMXBs as a population. I describe the search for XRBs in the Phoenix dwarf galaxy, a Local Group dwarf irregular galaxy which share many similarities with the Small Magellanic Cloud (SMC), which has an apparent overabundance of HMXBs. Finally, I discuss why the BeXRB population in the SMC is ideal for population studies and outline the work done to search for evidence for two different neutron star formation channels in their physical parameters

The X-ray emission from accreting black holes provides the perfect probe for testing the geometry, behaviour and conditions present in the innermost regions of the accretion flow. In this thesis I use X-ray spectral analysis to investigate the properties of accreting black holes that extend over several orders of magnitude in accretion rate (m˙ E) and black hole mass (MBH), from the stellar mass black holes in X-ray binary systems (XRBs)to the supermassive black holes in active galactic nuclei(AGN). Firstly, through a survey of X-ray emission in the nuclei of nearby galaxies I show that the usefulness of the X-ray to optical line ratios as a Compton-thick diagnostic does not extend to low luminosity AGN, and instead these ratios may have more practical use in distinguishing between AGN and non-AGN emission processes. Secondly, and more importantly, the main focus of this thesis is upon the variability of the Comptonised power-law X-ray spectral component, and more specifically an examination of how the photon index

A multiwavelength analysis of M31’s globular clusters and their low mass X-ray binaries by Mark B. Peacock Globular clusters (GCs) are dense groups of thousands to millions of stars. They are often very old systems with ages similar to those of their host galaxies and the early Universe. These clusters provide unique laboratories for astrophysical research and have been used by countless studies to improve our understanding of the Universe. In particular, they are ideal locations for studying stellar evolution and the formation and evolution of galaxies. They also provide unique locations for studying individual exotic objects, such as X-ray binaries. In this study, I investigate the properties of GCs in the nearby spiral galaxy, M31. This galaxy hosts the largest GC population in the Local Group. This, combined with its relative proximity to us, makes it an important bridge between studies of Galactic and extragalactic GCs. However, previous catalogues of these clusters have suffered from significant inhomogeneity and contamination from both stars and galaxies. In this contribution I present new, homogeneous, optical and near infra-red photometry of the M31 GC system. In addition to this, the structural parameters for over half of the known clusters are determined through fitting point spread function convolved King models to their density profiles. This photometry is used to remove significant contamination from non-cluster sources in previous cluster catalogues and to confirm a large population of young clusters in the M31 cluster system. Determining the properties of these clusters is very important in investigating both this, and other, GC systems. It is also of great benefit in investigating the exotic objects hosted by these clusters. I combine these data with archived XMM Newton observations, to study the low mass X-ray binaries (LMXBs) in M31’s clusters. LMXBs are known to be relatively common in GCs and, through studying the properties of the GCs which host them, it is possible to investigate the effects of cluster environment on the formation and evolution of these systems. From this work, I demonstrate that the presence of LMXBs is proportional to the stellar collision rate of a GC. This provides good observational evidence that these LMXBs are formed through dynamical interactions. These data are also used to consider the morphology of horizontal branch stars in M31’s GCs. Published GALEX ultraviolet observations of these clusters are used as a probe into their hot stellar populations. From this work, I propose a relationship between the core density of these clusters and their ultraviolet colour. This result suggests that the formation of (FUV bright) extreme horizontal branch stars may be enhanced in dense stellar environments through stellar interactions

A low energy gamma ray telescope, and the results of its observations are described. The telescope consisted of four sodium iodide crystals, each of 120 cm(2) area, occulted by lead discs. Charged particles are rejected using scintillation, anti-coincidence shields. The telescope was flown from Palestine, Texas in 1974. Gamma rays were observed from the Grab Nebula, the pulsar NP0 532, and the atmospheric background. No evidence for a gamma ray burst was found, giving an upper limit of less than 5.8 x 10(3) bursts per year of intensity greater than 1.6 x 10(-6) ergs cm(-2) Various types of existing, and planned, gamma ray detectors, and successful gamma ray observations are reviewed. Detailed calculations of the detection efficiency of a Double Compton telescope are presented and these results led to the development of the MISO low energy gamma ray telescope. Preliminary calculations of the detection efficiency of an Anticollimated Double Compton telescope are presented, which suggest that further, more detailed investigation of this type of detector would prove fruitful.

This thesis presents analyses of flickering aurora observed using the state-of-theart Auroral Structure and Kinetics (ASK) multi-monochromatic ground-based auroral imager. Flickering aurora is observed as rapid (typically 2–20 Hz) oscillations in auroral luminosity. There are several competing theories for the generation mechanism of flickering aurora, although all use electromagnetic ion cyclotron (EMIC) waves. The work presented in this thesis has shown that precipitating electrons producing flickering aurora are accelerated by Landau damping of the EMIC wave, and that the wave parallel phase velocity is the primary factor limiting the electron precipitation energy. In addition, evidence is presented supporting the theory that very small structures in flickering aurora are caused by interference between multiple EMIC waves. A combined electron transport and ion chemistry model (the Southampton Ionospheric Model) has been used in this work to allow quantitative estimates of the energy of precipitating electrons responsible for aurora observed with ASK. This thesis also presents a novel technique for intercalibrating optical and particle measurements of the aurora made by instruments onboard the Reimei satellite using the Southampton Ionospheric Model. This allows estimates of the flux of precipitating electrons at high energies above the detection limit of the Electron Spectrum Analyzer (ESA) particle detector. Optical images of the aurora obtained using the Multispectral Auroral Camera (MAC) instrument are also calibrated, allowing quantitative estimates of the auroral brightness without contamination from background light and auroral light reflected from the Earth. The technique has many possible applications in auroral studies using the Reimei satellite.

The known population of high-mass X-ray binaries in the Small Magellanic Cloud is continually growing and is now a similar size to that of the Milky Way, despite a significant mass difference between the two galaxies. In this thesis, I present multi-wavelength observations of Be/X-ray binaries that have undergone an outburst during the past three years, including the discovery of new systems and extended outbursts from previously known sources. The results are discussed in terms of both the underlying physics of individual outbursts and how the growing SMC population is helping our understanding of the formation and evolution of highmass X-ray binaries. In particular, I describe the orbital analysis of every extended X-ray outburst detected by the Rossi X-ray Timing Explorer and present the first significant sample of systems outside of the Milky Way for which a binary orbital solution is known.

The relationship between the X-ray and optical variability in Seyfert galaxies by Elm´e Breedt Lategan Seyfert galaxies have been known to vary since shortly after their discovery, but the origin of the optical variability and its relationship to the X-rays, have not been well established. Presented here is a comprehensive comparison between the long term X-ray and optical emission in a sample of seven Seyfert galaxies, to determine the relationship between the X-ray and optical variations. It is shown that the observed optical variability is the sum of several independent mechanisms: the short time-scale variability is dominated by X-ray reprocessing, but variations intrinsic to the disc, such as propagating accretion rate fluctuations, add considerable variability power on long time-scales. Cross-correlation analysis reveal a statistically significant correlation between the X-ray and optical emission of all the galaxies under investigation, with the optical variations following the X-rays by 1–2 days. This time-scale is consistent with the expected light travel time from the central X-ray source to the optically emitting region of the accretion disc. Although this is a strong indicator of X-ray reprocessing by the disc, it is also clear that reprocessing cannot account for all the optical variations observed. At least one source displays clear long time-scale (years) variations in the optical with no apparent counterpart in the X-rays, and in others the long term optical amplitude exceed that of the X-rays. It is shown that these long time-scale optical variations must originate from an independent variability mechanism, possibly variations in the accretion rate or the geometry of the system. There is also evidence that there may be a significant contribution to the optical emission from as far out as the dust torus. Finally it is shown that there may be a dependence of the strength of the X-ray/optical correlation on the disc temperature and black hole mass.

The galaxy stellar mass function (GSMF) has been well measured by the Galaxy And Mass Assembly (GAMA) survey down to a mass of $\mstar = 10^{8}\,\msun$. Below this mass the values produced so far can only be taken as lower limits on the distribution. One source of this incompleteness is failing to account for undetected low-surface-brightness galaxies (LSBGs) within the fields observed. These galaxies have been known about for some time, however, taking a true census of their population is difficult because of the biases associated with their detection in large surveys. The focus of this thesis is to improve the census of these objects and to try and apply those results to the low-mass end of the GSMF. First the SDSS data used to create the original GAMA catalogues is re-examined for low-surface brightness galaxies (LSBGs). To accomplish this SDSS DR7 imaging was used and a specialised detection algorithm created. This was based on masking sources detected with SDSS \textsc{photo}, combining the {\it gri} images with a weighting that maximises the signal-to-noise (SNR), and smoothing the images. These were then run through a detection algorithm which finds all pixels above a set threshold and groups them based on their proximity to one another. The list of detections is cleaned of contaminants such as diffraction spikes and the faint wings of masked objects. This produces a final list of 343 newly discovered LSBGs. Measuring their $g-i$ and $J-K$ colours shows that most are likely to be at redshifts less than 0.15. The photometry is carried out using a flexible auto aperture for each detection giving surface brightness measurements of $\mu_{r} > 23.7$\,mag arcsec$^{-2}$ and $r$-band magnitudes of $r_{AUTO} \gtrsim 20$\, mag. Through this method we show there are at least 343 new LSBGs within the GAMA fields, however none of these galaxies are bright enough to be within the GAMA main survey limit. It was noticed during the previous work that the detected LSBGs were all visible in VIKING $Z$-band data, and so it was decided to run a more traditional detection algorithm over these data to increase the number of LSBGs detected. This could then be used to create a new GSMF based on the deeper $Z$-band imaging. By using this imaging it will be possible to detect many more faint galaxies than previously and also increase the depth to which surface brightness can be effectively probed. The three GAMA equatorial regions have had mosaics created from the $Z$-band imaging which are searched using \textsc{Source Extractor} (\textsc{SExtractor}) and catalogues of detections are made. These are then compared to the original GAMA catalogues to remove duplicate detections and identify any possible new ones. Criteria are then applied to the source lists to remove any stars or objects which are either not galaxies or artefacts. This then leaves only likely galaxies in the catalogue to be used. The next stage is to create the GSMF based on the data collected, through applying corrections for the volume searched, and the spectroscopic completeness of the objects after they have been binned in $g-i$, $J-K$, and apparent magnitude. The GSMF created is compared to previous versions, namely that from \cite{Baldry+2012}, and a rise in the number density at masses of $\mstar \le 10^{8}\,\msun$ is shown. These can still only be thought of as lower limits however as improvement to the imaging can still be made in future surveys. With a full catalogue obtained using the VIKING Z-band it was decided to revisit the detection algorithm developed in Chapter 2. A pilot study was undertaken to both test the validity of the method, and the suitability of the VIKING images for further study. Whilst applying the detection algorithm to the data improved the ability to detect low surface brightness features within the images, no new galaxies were discovered over the pilot study area of $0.75$ deg$^{2}$. This method applied to the Z-band data, even over the full area, is unlikely to lead to large numbers of new LSBGs. This work has shown that there are still LSBGs in the field to be discovered. The result of finding new LSBGs has been to raise the measurement of the GSMF at low masses, further constraining the number of low mass galaxies in the Universe.