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The initial results from the Durham/UKST Galaxy Redshift Survey are presented here. Using this redshift survey the luminosity, clustering and dynamical properties of galaxies in the Universe are investigated. The 3-D distribution of galaxies in the Durham/UKST survey appears "cellular” on 50-100h(^-1) Mpc scales (where h is Hubble's constant in units of 100 kms(^-1) Mpc(^-1)) and is clearly more complex than a simple 1-D periodic pattern. The optical galaxy luminosity function of the Durham/UKST survey is estimated and can be fit by a Schechter function. Comparison with other determinations of the luminosity function shows good agreement, favouring a flat faint end slope to M(_b J) ~ -14.The redshift space 2-point correlation function clustering statistic is estimated from the Durham/UKST survey. Comparison with previous estimates from other redshift surveys again shows good agreement and the Durham/UKST survey gives a detection of large scale power above and beyond that of the standard cold dark matter cosmological model on 10-40h(^-1)Mpc scales. The projected correlation function is also estimated from the Durham/UKST survey and is compared with models for the real space 2-point correlation function. To estimate this real space correlation function directly, a new application of the Richardson-Lucy inversion technique is developed, tested and then applied to the Durham/UKST survey. The effects of redshift space distortions on the 2-point correlation function are investigated and modelled in the non-linear and linear regimes. The 1-D pairwise velocity dispersion of galaxies is measured to be 416 ± 36 kms(^-1) which, while being consistent with the canonical value of ~ 350 kms(^-1) is slightly smaller than recently measured values. However, this value is inconsistent with the ~ 1000 kms(^-1) value as measured in the standard cold dark matter cosmological model at a high level of significance. The ratio of the mean mass density of the Universe, Ω, and the linear bias factor, b (relating the galaxy and light distributions), is then calculated to be Ω(^0.6)/b = 0.45 ± 0.38. This favours either an open (Ω < 1) and unbiased (b = 1) Universe or a flat (Ω = 1) and biased (b ~ 2) Universe.

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Massive stars play a key role in shaping the local Universe but their formation process remains enigmatic. Emission from the 6.67 GHz, class II masing transition of methanol has proven a powerful tracer of where massive star formation regions are at their earliest evolutionary stages. Presented here are multi-wavelength observations to investigate the molecularlionised gas and (proto) stellar populations in cores traced by methanol maser emission, with the aim of investigating the earliest evolutionary stages of massive star formation and the role of methanol masers as a diagnostic of the state that star formation has reached within a core. Observations of para-ammonia [NH3 (1,1) --- (5,5)] and 24 GHz continuum emission were taken with the Australia Telescope Compact Array towards 21 southern Galactic hot molecular cores traced by 6.7 GHz methanol maser emission. NH3 was detected toward every region. For each core we extract and fit characteristic NH3 spectra and calculate the continuum properties. We split the cores into four groups based on their observed association with NH3 , 24 GHz continuum and methanol maser emission. We find evidence based on the kinetic temperatures and gas kinematics that the cores in the groups are at different evolutionary stages. In addition, we find 24 GHz continuum emission towards some methanol masers which had no 8 GHz continuum counterparts. We posit these could be hyper-compact HII regions: more dense and younger ionised gas than the ultra-compact HII regions. The NH3 (4, 4) and (5, 5) emission is always unresolved and at the methanol maser location, suggesting the methanol masers are located at the warmest part of the core. The fact that several cold cores also contained methanol masers suggests they trace regions at stages shortly after a suitable powering source has formed, right through to relatively evolved UCHII regions. While remaining a good general tracer of young MSF regions, the presence of a methanol maser does not single out any particular evolutionary stage. High resolution (~0.36"), multiple-filter, mid-IR images using Michelle on Gemini North were taken toward three hot molecular cores signposted by methanol maser emission. We find each region contains multiple, very red, luminous (50-40,000 Leo) sources, some of which lie at extremely small angular separations corresponding to linear separations of ?1700AU. Assuming the MlR point sources are embedded stellar objects, and the observed gas mass provides the bulk of the reservoir from which the stars formed, it is difficult to generate the observed distributions for the most massive cluster members from the gas in the cores using standard forms of the IMF. Deep, wide-field J, Hand Ks images were taken with IRIS2 on the Anglo Australian Telescope, towards the massive star formation region G305.2+0.2 and combined with 3.6, 4.5, 5.8 and 8.0??m data from the GLIMPSE survey on the Spitzer Space Telescope. After removing contamination from foreground stars, sources were separated, based on their IR colour, to investigate the properties of the embedded stellar populations. While strong extended emission in the GLIMPSE images hampered investigation towards the known sites of massive star formation, a sizable population of IR excess sources are found in the surrounding region free from these completeness effects. Investigation reveals the recent star formation activity in the region is more widespread than previously known. The embedded cluster in the region, G305.24+0.204 may have played a role in triggering further sites of star formation. Finally, we investigate the distribution of IR excess sources towards the cluster, in particular their apparent lack towards the centre compared with its immediate environs.

Thesis (Ph.D. 1978) from the Department of Mathematical Physics, University of Adelaide.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Chicago, Dept. of Astronomy and Astrophysics. / Includes bibliographical references. Also available on the Internet.

Licentiatavhandling (sammanfattning) Karlstad : Karlstads universitet, 2009. / E-bok.

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Orientador: Rogério Rosenfeld / Banca: Bruto Max Pimentel Escobar / Banca: Rudnei de Oliveira Ramos / Resumo: O modelo cosmológico inflacionário postula uma rápida expansão do universo primordial, denominada inflação, que pode resolver certas diflculdades da cosmologia padrão. Em modelos inflacionários mais simples a expansão acelerada é causada pela densidade de energia armazenada em um campo escalar denominado inflaton. Após a fase inflacionária, o universo encontra-se em um estado frio e sem partículas. Deve haver um mecanismo responsável pelo reaquecimento do universo. Nesta dissertação, primeiramente fazemos uma revisão simples da cosmologia padrão e inflacionária. Posterior mente, realizamos um estudo detalhado de três diferentes processos de reaquecimento: ressonância paramétrica, instabilidades taquiônicas e reaquecimento perturbativo. Finalmente, fazemos uma análise deste processo para um modelo de inflação quintessencial usando o programa LATTICEEASY / Abstract: The inflationary cosmological model postulates a fast expansion of the eaxly universe, called inflation, which can solve some issues of the standard cosmological model. In simple inflationary models the accelerated expansion is caused by the energy density stored in a scalar field called inflaton. After the inflationary phase, the universe is in a cold state and without particles. There must be a mechanism responsable for its reheating. In this dissertation we flrstly review the standard and inflationary cosmologies. We then perform a detailed study of three different reheating processes: parametric ressonance, tachyonic instabilities and perturbative reheating. Finally, we mahe an analysis of this process for a quintessencial inflation model using the program LATTICEEASY / Mestre