Dissertations / Theses on the topic 'The early history of astronomy and cosmology'

In this thesis, we present a new photometric catalogue of the local Coma galaxy cluster in the Johnson U- and V- bands. We cover an area of 3360arcmin(^2) of sky, to a depth of V = 20mag in a 13 arcsec diameter aperture, and produce magnitudes for ~ 1400 extended objects in metric apertures from 8.8 to 26arcsec diameters. The mean internal RMS scatter in the photometry is 0.014mag in V, and 0.026mag in U, for Via(_13) < 17mag. We use this photometric catalogue to place limits on the levels of scatter in the colour- magnitude relation (CMR) in the Coma cluster. We subdivide the galaxy population by morphology, luminosity and position on the sky, and analyse the CMR in each of them. The lowest levels of scatter are found in the elliptical galaxies, and the late type galaxies have the highest numbers of galaxies blue-wards of the CMR. We finds signs of decreased scatter and systematically bluer galaxy colours with increasing projected radius from the center of the cluster, and attribute it to a mean galactic age gradient. We find that the typical mass of galaxies within clusters can increase by a factor of two through dissipationless merging without destroying the CMR. We compare the spectral line indices of galaxies in the Coma cluster with their deviation from the mean colour-magnitude relation (CMR). We find that the CMR in Coma is driven primarily by a luminosity-metallicity correlation, however we cannot rule out a contribution from age effects. Colour deviations blue-ward of the mean relation are strongly correlated with the Hydrogen Baimer line series absorption, indicating the presence of a young stellar population in these blue galaxies. We use a wavelet code to suggest an association between X-ray cluster substructure and 'E+A' galaxy activity in high redshift clusters.

Thesis (Ph. D.)--University of Oregon, 2006.<br>Typescript. Includes vita and abstract. Includes bibliographical references (leaves 75-80). Also available for download via the World Wide Web; free to University of Oregon users.

In this thesis we discuss two key problems: the cosmological constant problem (CCP), an issue that primarily manifests itself in late universe cosmology; and the process of thermalisation during the post-inflationary reheating phase of the early universe. We start by giving a brief review of general relativity, discussing both its successes and failures, in particular, why one might consider modifications of it. We then delve into the aspects of early and late universe cosmology that we aim to address in the research discussed in this thesis. Starting with an overview of the inflationary paradigm, and the need to reheat the universe post-inflation, we give a review of previous research that has been conducted in this area. We then move on to discuss the CCP in detail, in particular, why it is such an issue. After setting the scene for this problem, we proceed to discuss how to approach finding a resolution to it, highlighting certain stumbling blocks that one needs to be mindful of. Having set the scene, we then present a potential solution to the CCP, involving a scalar-tensor modifed theory of gravity, so-called Horndeski theory. Building upon a class of Horndeski theories providing self-tuning solutions to the CCP, we provide a generalisation in which matter interacts with gravity via a disformal coupling to the spacetime metric. We establish the form of the disformally self-tuning Lagrangian on a cosmological Friedmann-Robertson-Walker background, and show that there exist non-trivial self-tuning solutions. In the latter half of this thesis, we move on to review the literature on the non-perturbative description of the early stages of reheating, so-called preheating. With the motivation to study the less well understood thermalisation process that must necessarily take place in this phase, we then present a toy model preheating theory, in which we account for the effects of thermalisation from its onset. Within the density matrix formalism, we derive a (self-consistent) set of quantum Boltzmann equations, which are able to describe the evolution of an ensemble of self-interacting scalar particles that are subject to an oscillating mass term. In particular, we apply this to the preheating scenario in order to study the evolution of scalar particle number densities throughout this process. We then conclude by discussing our numerical analysis of the Boltzmann equations, drawing attention to some important results and features that manifest using this approach, in particular, how the process differs from the standard analysis through the inclusion of thermalisation.

The paper aims to show that Andean myth, on one level, represents a technical language recording astronomical observations of precession and, at the same time, an historical record of simultaneous social and celestial transformations. Topographic and architectural terms of Andean myth are interpreted as a metaphor for the organisation of and locations on the celestial sphere. Via ethnoastronmical data, mythical animals are identified as stars and placed on the celestial sphere according to their "topographical " location. Tested in the planetarium, these "arrays" generate clusters of dates - 200 B.C. and 650. A. D. Analysis of the names of Wiraqocha and Manco Capac indicates they represent Saturn and Jupiter and that their mythical meeting represents their conjunction in 650 A.D. The astronomy of Andean myth is then used as an historical tool to examine how the Andean priest-astronomers recorded the simultaneous creation of the ayllu and of this distinctive astronomical system about 200 B.C. The idea that the agricultural ayllu, with its double descent system stressing the importance of paternity, represents a transformation of society from an earlier matrilineal/horticultural era is examined in light of the sexual imagery employed in myth. Wiraqocha’s androgyny and the division of the celestial sphere into male (ecliptic) and -female(celestial equator = “earth” ) are interpreted as cosmological validations of the new social structure.

This Thesis is written in three parts. The first part describes the analytic calculation of the unequal-time correlator of cosmic strings and superstrings. The first efficient constraint analysis of all string and superstring network parameters is performed. By studying the effect of cosmic strings on the cosmic microwave background (CMB) radiation it is discovered that cosmic strings must make up a vanishingly small proportion of the energy density of the universe. The constraints on string network parameters are all skewed toward reducing the magnitude of energy density arising from strings. Also in this Part, a better comprehension of the unconnected segment model (USM) was gained. In particular, a greater understanding of the string scaling parameter $L_f$ was garnered, as well as finding the reason why the USM tends to provide greater power than simulations of Nambu-Goto cosmic strings. The second part contains a detailed description of statistical cosmology and how differences between parameter constraints from different data sets can lead to misleading quantification of discordance. The majority of this part describes different methods of quantifying differences between probability distributions and how these can be interpreted. In particular, using the most up-to-date data possible, differences between parameter constraints using the CMB and probes of large scale structure (LSS) in the universe can be measured. With current data the discordance can be interpreted as a low level of disagreement, but the application of prior ranges on well known parameters can force the tension to be greater. Using data from earlier work, this issue is considered in greater detail, with extensions to the accepted LCDM model added to test if the discordance can be alleviated. These extensions include the addition of active or sterile neutrinos and even ad-hoc changes to the primordial power spectrum. Although there are slight hints that these may help, when considering only the new data it might be unwise to believe that the discordance between parameter distributions from different data sets exists to a degree where the modifications are necessary. Finally, application of deep learning to astrophysical observations is discussed. Using neural networks to learn about specific problems is de rigueur and their use in astronomy and cosmology is a promising field of study. In particular, applying raw data to neural networks can often outperform, or add enhanced features, to what is possible with current, non-empirical feature detection. The classification of supernovae from their light curves can be achieved using a specific machine learning architecture called a recurrent neural network (RNN). Using the raw data from supernova light curves, the RNN is able to learn about features in sequences which can be used to classify types of supernova. Although a large training set is needed to perform as well as current techniques, one major advantage the RNN method has is the possibility of early detection. Rather than needing the entire light curve to perform statistical fits to categorise the supernova type, relatively little information from the early observation data is needed to classify using the RNN. Installing RNN on machinery for observation would save a vast amount of time by early classification since only supernovae of interest can be concentrated on.

Gamma-ray bursts (GRBs) are still puzzling scientists even 40 years after their discovery. Questions concerning the nature of the progenitors, the connection with supernovae and the origin of the high-energy emission are still lacking clear answers. Today, it is known that there are two populations of GRBs: short and long. It is also known that long GRBs are connected to supernovae (SNe). The emission observed from GRBs can be divided into two phases: the prompt emission and the afterglow. This thesis presents spectral analysis of the early X-ray afterglow of GRBs observed by the {\it Swift} satellite. For the majority of GRBs the early X-ray afterglows are well described by an absorbed power-law model. However, there exists a number of cases where this power-law component fails in fully describing the observed spectra and an additional blackbody component is needed. In the paper at the end of this thesis, a time-resolved spectral analysis of 74 GRBs observed by the X-ray telescope on board {\it Swift} is presented. Each spectrum is fitted with a power-law and a power-law plus blackbody model. The significance of the added thermal component is then assessed using Monte Carlo simulations. Six new cases of GRBs with thermal components in their spectra are presented, alongside three previously reported cases. The results show that a cocoon surrounding the jet is the most likely explanation for the thermal emission observed in the majority of GRBs. In addition, the observed narrow span in radii points to these GRBs being produced in similar environments.<br><p>QC 20171031</p>

In recent years, the increasingly precise constraints on the value of the Hubble constant, H0, have highlighted a discrepancy between the results arising from early-time and late-time measurements. A potential solution to this so-called Hubble tension is the hypothesis that we reside in a cosmic void, i.e. an underdense cosmic neighbourhood characterized by a faster local expansion rate. In this thesis, we model this scenario through the Lemaître-Tolman-Bondi formalism for an isotropic but inhomogeneous universe containing matter, curvature and a cosmological constant, which we denote by ΛLTB. We numerically implement this framework with two different formulations for the local matter density profile, respectively based upon a more realistic Gaussian ansatz and the idealized scenario of the so-called Oppenheimer-Snyder model. We then constrain the background cosmology and the void parameters involved in each case through a Markov Chain Monte Carlo analysis with a combination of recent data sets: the Pantheon Sample of type Ia supernovae, a collection of baryon acoustic oscillations data points from different galaxy surveys and the distance priors extracted from the latest Planck data release. For both models, the resulting bounds on the investigated parameter space suggest a preference for a -13% density drop with a size of approximately 300 Mpc, interestingly matching the prediction for the so-called KBC void already identified on the basis of independent analyses using galaxy distributions. We quantify the level of improvement on the Hubble tension by analyzing the ΛLTB constraints on the B-band absolute magnitude of the supernovae, which provides the calibration for the local measurements of H0. Since no significant difference is observed with respect to an analogous fit performed with the standard ΛCDM model, we conclude that the potential presence of a local void does not resolve the tension.

We have measured central line strengths and line-strength gradients for a complete sample of early-type galaxies in the Fornax cluster, comprising 11 elliptical and 11 lenticular galaxies, more luminous than M(_B) = -17. We find that the centres of Fornax ellipticals follow the locus of galaxies of fixed age in Worthey's models and have metallicities varying roughly from half solar to 2.5 times solar. Line-strength gradients indicate that elliptical galaxies do not show age gradients with radius but do exhibit a decrease of ~ 0.4 dex in [Fe/H] between the centre and one effective radius. The centres of lenticular galaxies however exhibit a substantial spread to younger luminosity weighted ages indicating a more extended star formation history. Metallicity gradients are generally shallower than for ellipticals. Five of the faint S0s have experienced a central starburst on top of an underlying older stellar population. Our conclusions are based on several age/metallicity diagnostic diagrams in the Lick/IDS system comprising established indices such as [MgFe] and Hβ as well as new and more sensitive indices such as C4668, Fe3 and Hγ(_A). The inferred difference in the age distribution between lenticular and elliptical galaxies is a robust conclusion as the models generate consistent relative ages using different age and metallicity indicators even though the absolute ages remain uncertain. The absolute age uncertainty is caused by the effects of non-solar abundance ratios which are not accounted for in the stellar population models. We find that Es are generally overabundant in magnesium where the most luminous galaxies show stronger overabundances. The luminosity weighted stellar populations of young S0s are consistent with solar abundance ratios, however the bulges of the two large S0s in our sample have [Mg/Fe] > 0. We have analysed in detail the sources of scatter in the Mg-crg relation by investigating the effects of age, metallicity and [Mg/Fe] variations. We find that young stellar populations are responsible for most of the scatter towards weak Mg-absorption. However, for the roughly coeval ellipticals the scatter at a given ctq is correlated with [Mg/Fe variations; metallicity and age effects seem to be less important. The young luminosity weighted ages of the faint S0s in the Fornax cluster are consistent with the recent discovery that the fraction of S0 galaxies in intermediate redshift clusters is a factor of 2-3 lower than found locally, and suggests that a fraction of the cluster spiral galaxy population has evolved into these faint S0s in the 5 Gyrs interval from z = 0.5 to the present. One of the proposed transformation mechanisms is the galaxy harassment picture. The properties of young S0s with large bulge to disk ratios in our sample are remarkably similar to the proposed end-products of galaxy harassment. However, we note that there are young disky S0s which are unlikely to be the result of harassment. Two of the faintest lenticular galaxies in our sample have blue continua and extremely strong Balmer-line absorption suggesting starbursts < 2 Gyrs ago.

The gradual blending of classical science and epistemology with indigenous/traditional practices and modes of understanding (particularly magic and religion) in the early western Middle Ages tends to be misunderstood. The purpose of this study is to address the reason(s) why the early medieval West has been labeled an irrational, unscientific â Dark Ageâ in order to point out that this conceptionâ s existence has more to do with limited historical perspectives than with reality. The anachronistic superimposition of modern presuppositions and methodological expectations is a very old phenomenon. Ironically, however, it has crept into the history of science and extended to ostensibly objective â scientificâ historiography to such a degree that dismissiveness regarding the other ways of knowing that have informed our scientific and epistemological development frequently tends to obscure historical continuity. My goal in this undertaking is to firmly establish how we may understand that the intellectual revolution beginning in twelfth-century Europe was founded on a rich and multifarious tradition of knowledge and understanding; the preceding seven or eight centuries of the early Middle Ages was not one of intellectual â darknessâ and should not be discarded as such. The approach I have taken is intended to demonstrate, rather than simply state, this goal by roughly imitating of the process of intellectual transmission in the early Middle Ages. Therefore, primary sources are supplemented by numerous secondary interpretations from various academic disciplines in the hope that collecting and reforming ideas in this fashion will draw out the inherent connectivity of ideological thought structures and approaches to the natural world.<br>Master of Arts

<p> This dissertation is a series of textual case studies on nontraditional sources for <i>li</i>[special characters omitted]"calendro-astronomy" circa 250 BCE - 250 CE: (1) the silk manuscript guide to military planetary astronomy/astrology <i>Wuxing zhan</i>[special chracters omitted] (168 BCE), (2) excavated calendars and state <i>li</i> manuals, and (3) the <i>Jin shu</i>'s [special characters omitted] record of the debate surrounding a failed attempt at li reform in 226 CE. This selection affords us a number of unique cross sections through the astral sciences. Balancing transmitted with excavated sources, I emphasize realia and their perspective on era technical knowledge, the formats in which it was produced and consumed, and its transmission and practice beyond an elite court-centered context. In addition to the three elements of <i>li</i>--calendrics, eclipses, and planetary astronomy--my selection draws together the broad array of astral sciences, exploring distinctions in genre, sociology, and epistemology between, for example, mathematical astronomy, hemerology, and omenology, and the (tortuous) processes by which knowledge moved between them. Each chapter also juxtaposes the normative descriptions of manual literature with products of practice&mdash;tables, calendars, and test results&mdash;to reflect upon the distance between them and, thus, the limitations of the former as historical testimony. Across these cross sections, my study focuses on the question of empiricism and progress. I foreground these topics <i>not</i> because they define twentieth-century notions of science but because, as I argue, they define early imperial notions of <i>li</i>&mdash;a point that our twenty-first-century aversion to positivism and Whig history tends to obscure. To this end, I catalog the conceptual vocabulary of observation and testing, submit empirical practices to mathematical and sociological analysis, and, most importantly, explore the formation and function of legend&mdash;the histories of science that early imperial actors wrote and recounted in their own day. </p><p> As it stands, the dissertation has four body chapters. Chapter 1 provides a history and sociology of the astral sciences in the Han, covering the sources, legend, and conceptual vocabulary of <i>li</i>, the history of Han li from the perspective of both ideas and institutional reforms, and a survey of participants' backgrounds, motivations, education, and epistemological contentions. Chapter 2 examines how the Wuxing zhan manuscript segregates and conflates distinct genres of planetary models, then sketches the subsequent history of these genres, showing how, despite seemingly opposite orientations to reality, actors gradually rewrote and reassessed (crude) hemerology-based omenological (<i>tianwen</i>[special characters omitted]) models through the lens of progress made in mathematical (<i>li</i>) ones. Chapter 3 explores a similar gulf that opened between astronomy and calendrics in this period, as well as the gulf between imperial ideology&mdash;within which the calendar was the premier symbol of cosmo-ritual dominion&mdash;and the actualities of the production, distribution, and use of calendars in a manuscript culture. Lastly, chapter 4 analyzes the two epistemic strategies at the center of (the <i>Jin shu</i>'s take on) the circa 226 CE court debate on <i>li</i>: the quantitative determination of "tightness" (accuracy) of lunisolar and planetary models through competitive testing, and the contestation of claims through the deployment of precedence from the history of the field.</p>

This thesis uses theoretical studies, and numerical simulations to provide results of the experimental reach to detect the QCD axion as dark matter in a Non-standard cosmological background. Assuming that the QCD axion constitutes the full CDM abundance of the universe, this thesis elaborates on its potential detection from experimental setups for the mass window of the axion. The set of results that is obtained here are the relic CDM energy density of axions produced by the vacuum realignment mechanism and the CDM energy density of axions produced from the decay of a network of cosmic strings. This thesis provides results regarding the possibility to detect a primordial gravitational wave relic, which is possible within some favorable cosmological scenarios for the background.

Philosophiae Doctor - PhD<br>The standard model of cosmology (the ɅCDM model) has been very successful and is compatible with all observational data up to now. However, it remains an important task to develop and apply null tests of this model. These tests are based on observables that probe cosmic distances and cosmic evolution history. Supernovae observations use the so-called `standard candle' property of SNIa to probe cosmic distances D(z). The evolution of the expansion rate H(z) is probed by the baryon acoustic oscillation (BAO) feature in the galaxy distribution, which serves as an effective `standard ruler'. The observables D(z) and H(z) are used in various consistency tests of ɅCDM that have been developed. We review the consistency tests, also looking for possible new tests. Then the tests are applied, first using existing data, and then using mock data from future planned experiments. In particular we use data from the recently commissioned Dark Energy Survey (DES) for SNIa. Gaussian Processes, and possibly other non-parametric methods, used to reconstruct the derivatives of D (z) and H (z) that are needed to apply the null tests of the standard cosmological model. This allows us to estimate the current and future power of observations to probe the ɅCDM model, which is the foundation of modern cosmology. In addition, we present an improved model of the HI galaxy number counts and bias from semi-analytic simulations, and we use it to calculate the expected yield of HI galaxies from surveys with a variety of phase 1 and 2 SKA configurations. We illustrate the relative performance of the different surveys by forecasting errors on the radial and transverse scales of the BAO feature. We use the Fisher matrix method to estimate the error bars on the cosmological parameters from future SKA HI galaxy surveys. We find that the SKA phase 1 galaxy surveys will not contend with surveys such as the Baryon Oscillation Spectroscopic Survey (BOSS) whereas the full "billion galaxy survey" with SKA phase 2 will deliver the largest dark energy Figure of Merit of any current or future large-scale structure survey.<br>South African Square Kilometre Array Project (SKA) and German Academic Exchange Service (DAAD)

Astronomical images are found on monumental structures and decorative art, and metaphorically in seasonal myths, and are documented by calendars. In Israel and the southern Levant, images of the sun, the moon, and the stars were common decorating motifs. They were found on walls, pottery, and seals and date to as early as the Chalcolithic period; for example, the wall painting of a star at Teleilat Ghassul (North 1961). This dissertation establishes that the people of the Levant were aware of the apparent movement of the sun, and this will be discussed in Chapter 4. They began recording through representation drawings, astronomical phenomena no later than the Chalcolithic/Early Bronze Age and continued to do so late into the Middle Bronze Age. The argument moves beyond the simple use of symbols to the use of images to represent constellations, with the focus on the constellation Leo in Chapter 5. Furthermore, the use of astronomy as a power and political tool is also suggested in Chapter 6. Nonetheless, the primary purpose that is addressed here is the tendency in Syro-Palestinian archaeology has been to attribute technological evidence found in the northern and southern Levant as diffused from Egypt or Assyria, particularly astronomy. This dissertation firmly establishes that astronomy was used in the southern Levant before any significant contact with the civilizations of Egypt or Assyria.

Made available in DSpace on 2017-07-10T18:26:29Z (GMT). No. of bitstreams: 1 Luiz Antonio Brandt.pdf: 1067816 bytes, checksum: 69a6a677b5382a0454f7bbd9551ddd1f (MD5) Previous issue date: 2011-12-08<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>In this thesis, we aim to conduct a study and reconstruction of the criticism that Galileo undertakes to physics and cosmology of Aristotle, and works as an anchor Sidereus Nuncius and First Day of Dialogue Concerning the Two Chief World Systems. The arguments developed by Italian physicist these works, consolidating the Copernican theory and revolutionize the way we study nature. For centuries, the Western conception of the universe was supported by the assumptions of cosmology of Aristotle. Aristotelian cosmology had as fundamental points the idea of the incorruptibility of the heavens, the earth and the immobility of a hierarchy of elements. For the peripatetic, the cosmos was finite and heterogeneous, and was divided into two distinct regions: the sublunary (terrestrial) and above the Moon (heavenly). The telescopic observations made by Galileo in 1609, showing craters and mountains on the moon and Jupiter's satellites, were in evidence against the heaven-earth dichotomy proposed by Aristotle. For it revealed "imperfections" in the heavenly bodies, and showed that not all the stars had their revolutions as the center of the Earth, the idea of asking the same centrality in the cosmos. Moreover, the break with Aristotelian cosmology destabilizing the very physics of Aristotle, whose explanation of the movements of bodies depended on the cosmological structure, since there were three types of moves, straight toward the center, straight away from the center and circular around the center, which required a motionless earth occupying the center of the cosmos. The idea of centrality and immobility of the Earth is therefore fundamental point of Aristotelian physics and cosmology. Most of the work of Galileo Galilei seems to think about a central objective: the defense of the Copernican theory. Since his public adhesion to the Copernicanism in 1610, in Sidereus Nuncius, until Dialogue published in 1632, the Pisan Phisycist sought to break with the assumptions of the Aristotle s natural philosophy which supported the geocentric conception. As a result, it is in First Day of Dialogue that, certainly, we could find a more systematic and focused effort against the Aristotelic conception of world and its main characteristic: the dissociation of the cosmos into two distinct regions, the celestial and sublunary.<br>Nesta dissertação, temos como objetivo realizar um estudo e reconstrução das críticas que Galileu empreende à física e à cosmologia de Aristóteles, tendo como âncora as obras Sidereus Nuncius e Primeira Jornada do Diálogo sobre os dois máximos sistemas do mundo. Os argumentos desenvolvidos pelo físico pisano nestas obras, consolidam a teoria copernicana e revolucionam a maneira de se estudar a natureza. Durante séculos, a concepção ocidental de universo esteve apoiada nos pressupostos da cosmologia de Aristóteles. A cosmologia aristotélica tinha como pontos fundamentais a ideia de incorruptibilidade do céu, de imobilidade da Terra e de uma hierarquia dos elementos. Para o peripatético, o cosmos era finito e heterogêneo, e se encontrava dividido em duas regiões distintas: a sublunar (terrestre) e a supralunar (celeste). As observações telescópicas realizadas por Galileu em 1609, ao mostrar crateras e montanhas na Lua, e satélites em Júpiter, constituíram-se em evidências contrárias à dicotomia céu-Terra proposta por Aristóteles. Pois revelavam imperfeições nos corpos celestes, e mostravam que nem todos os astros tinham como centro de suas revoluções a Terra, questionando a ideia de centralidade da mesma no cosmos. Além disso, a ruptura com a cosmologia aristotélica desestabilizava a própria física de Aristóteles, cuja explicação dos movimentos dos corpos dependia da estrutura cosmológica, uma vez que existiam três tipos de movimentos: retilíneo em direção ao centro, retilíneo se afastando do centro e circular em torno do centro, o que requeria uma Terra imóvel ocupando o centro do cosmos. A ideia de centralidade e imobilidade da Terra é, portanto, ponto fundamental da física e da cosmologia aristotélicas. Grande parte da obra de Galileu parece girar em torno de um objetivo central: a defesa da teoria copernicana. Desde a sua adesão pública ao copernicanismo em 1610, no Sidereus Nuncius, até o Diálogo publicado em 1632, o físico pisano buscou romper com os pressupostos da filosofia natural de Aristóteles que sustentavam a concepção geocêntrica. Com efeito, é na Primeira Jornada do Diálogo que poderemos encontrar um esforço mais sistemático e concentrado contra a concepção aristotélica de mundo e sua principal característica: a dualidade do cosmos.

Due to the finite speed of light and a vast, expanding universe, telescopes are just now receiving the light emitted by galaxies as they were forming in the very early universe. The light from these galaxies has been redshifted (stretched to longer, redder wavelengths) as a result of its journey through expanding space. Using sophisticated techniques and exceptional multi-wavelength optical and infrared data, we isolate a population of 378 galaxies in the process of formation when the Universe was only two billion years old. By matching the distinctive properties of the light spectra of these galaxies to models, the redshift, age, dust content, star formation rate and total stellar mass of each galaxy are determined. Comparing our results to similar surveys of galaxy populations at other redshifts, a picture emerges of the growth and evolution of massive, star-forming galaxies over the course of billions of years.

Orientador: Carlos Eduardo Ornelas Berriel<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem<br>Made available in DSpace on 2018-08-24T21:54:37Z (GMT). No. of bitstreams: 1 Caixeta_BrunaPereira_M.pdf: 41483159 bytes, checksum: 9da2fe0848c5c1d54ac61022e851cefe (MD5) Previous issue date: 2014<br>Resumo: Alguns anos antes da deflagração da Revolução Inglesa de 1640, que na Inglaterra deporia o regime monárquico e daria aos puritanos o controle de um regime pretensamente republicano, ocorreria uma série de erros políticos que contribuiriam para os conflitos que levaram à Guerra Civil. Boa parte deles adveio da política pró-Espanha assumida pelos dois primeiros reis Stuart, Jaime I e Carlos I, que, entre outras ações, não apoiaram as classes protestantes nas suas empresas de comercialização e colonização de mercados no exterior, deixando a situação econômica do país negativa. Diante do iminente fenecimento do regime monárquico, da Igreja Anglicana alicerçada no sistema episcopal e de aliança ao Estado, do perigo da Inglaterra se tornar domínio espanhol, Francis Godwin compõe por volta de 1629, publicado seu texto em 1638, a ficção utópica "The Man in the Moone". Sumarizando todo o conflito religioso e os deslizes do governo dos primeiros Stuart que caracterizou a Inglaterra nos 40 primeiros anos do século XVII, o presente estudo objetivará mostrar que essa ficção do espanhol Domingo Gonsales na sua viagem à lua, na passagem pela fictícia ilha de Santa Helena e pela China ocupada por jesuítas, debatendo as teorias de Copérnico, Galileu, Gilbert e Kepler na área da astronomia, se pretendeu uma defesa e proteção da Igreja Anglicana e do regime monárquico Tudor que aliava a Igreja ao Estado e favorecia a economia. Através do exemplo disciplinado e inovador dos jesuítas em missão na China no início do século XVII, Godwin intentará advertir os confusos reis, que a saída para os conflitos internos e externos ingleses estava no livre desenvolvimento da ciência, do comércio, e, agora diferente dos jesuítas, numa política adversária à Espanha e à mentalidade medieval e obsoleta católica<br>Abstract: Some years before the outbreak of the English Revolution of 1640, testifying that in England the monarchy and the Puritans would control an allegedly republican regime, there were a series of errors that contribute to political conflicts that led to the Civil War. Most of them came from the pro-Spanish political assumed by the first two Stuart kings, James I and Charles I, who, among other things, did not support the Protestant classes in their trading enterprises and colonization of overseas markets, leaving the economic situation of the country negative. Faced with the imminent withering of the monarchy, the Anglican Episcopal Church founded on the alliance with the State, the danger of Britain becoming a Spanish colony, Francis Godwin composed around 1629 and his text published in 1638, the utopian fiction "The Man in the Moone". Summarizing all the religious conflict and glides early Stuart England that characterized the first 40 years of the seventeenth century, this study will aim to show that this fiction of Spanish Domingo Gonsales on your trip to the moon, in his passage by the fictional island of Santa Helena and China populated by Jesuits, debating the theories of Copernicus, Galileo, Kepler and Gilbert in the field of astronomy, sought a defense and protection of the Anglican Church and the Tudor monarchy that allied the Church to the State and favored the economy. Through disciplined and innovative example of the Jesuit mission in China in the early seventeenth century, Godwin will bring and warn the confused kings, that the output for the English internal and external conflicts was the investment in science, commerce, and now different from the Jesuits, in opposition to Spain and the Catholic medieval mentality and obsolete policy<br>Mestrado<br>Historia e Historiografia Literaria<br>Mestra em Teoria e História Literária

Cette dissertation a pour objectif de fournir un éclairage nouveau sur la cosmologie philonienne à la lumière de la littérature apocalyptique judéo-chrétienne. Il s'agit reposer la question du lien entre Philon d’Alexandrie et la tradition apocalyptique judéo-chrétienne dans une optique qui se veut à la croisée de l’histoire des religions et de l’histoire de la philosophie. Après délimitation du corpus, on y aborde la question du rapport au mythe et à la théologie. La place est ensuite faite à la question des intermédiaires célestes (Anges, Logos, Esprit), ainsi qu’à la liturgie. Ce point nous mène à la figure du messie et aux raisons du silence de Philon à ce sujet. Cette étude entend ainsi porter un regard nouveau sur la pensée d’un auteur majeur de l’Antiquité qui accomplit la première grande synthèse entre le judaïsme et l’hellénisme, anticipant ainsi l’émergence des conditions métaphysiques du christianisme.<br>Doctorat en Philosophie<br>info:eu-repo/semantics/nonPublished

Understanding the formation and evolution of galaxies is a crucially important task in modern astronomy. It is well known that galaxy formation is strongly affected by the environments they reside in. Galaxy clusters, as the densest large-scale structures in the Universe, thus serve as ideal laboratories to study how galaxy formation proceeds in dense environments. Clusters already began to form at $z>2$, therefore to directly witness the early stage of galaxy formation in dense environments, it is necessary to identify progenitors of clusters (`protoclusters') and study their galaxy constituents within. In this thesis, I present two observational studies on high-redshift protoclusters at $z>3$. Utilizing multiwavelength data and different galaxy selection techniques, significant galaxy overdensities are found in the two protoclusters, which are predicted to evolve into Coma-like clusters by present day. Various types of galaxies are identified in the protocluster, such as normal star-forming galaxies, massive quiescent galaxies and post-starburst galaxies. Together with extreme and rare sources such as giant Lyman-alpha nebulae and brighest cluster galaxy, they paint a picture of how different galaxy populations trace the underlying dark matter halos. Finally, the environmental impact on galaxy properties appears to be a subtle one for these protoclusters, which might depend on the galaxy population one chooses to study.

Gravitational waves are truly transparent to matter in the Universe and carry the information of the very early epoch. We show that the energy density spectrum of the primordial gravitational waves has characteristic features due to the successive changes in the relativistic degrees of freedom during the radiation era. Our calculations are solely based on the standard model of cosmology and particle physics, and therefore these features must exist. Our calculations significantly improve the previous ones which ignored these effects and predicted a smooth, featureless spectrum. Going back in time to the beginning of the radiation era, reheating of the Universe must have taken place after inflation for primordial nucleosynthesis to begin. We show that reheating occurs spontaneously in a broad class of inflation models with [scientific symbols] gravity (Ø is inflaton). The model does not require explicit couplings between Ø and bosonic or fermionic matter fields. The couplings arise spontaneously when Ø settles in the vacuum expectation value (vev) and oscillates. This mechanism allows inflaton quanta to decay into any fields which are not conformally invariant in [scientific symbols] gravity theories. Applying the above method, we study implications of the large-N species solution to the hierarchy problem, proposed by G. Dvali, for reheating after inflation. We show that, in this scenario, the decay rates of inflaton fields through gravitational decay channels are enhanced by a factor of N, and thus they decay into N species of the quantum fields very efficiently. Without violating energy conservation, cosmological consideration places non-trivial constraints on Dvali's solution to the hierarchy problem. Going back in time still further, we study the period just before the beginning of reheating, the era of coherent oscillation of scalar fields. We show that non-Gaussian primordial curvature perturbations appear temporarily in the coherent oscillation phase after multi-field inflation. We directly solve the evolution equation of non-Gaussianity on super-horizon scales caused by the non-linear influence of entropy perturbations on the curvature perturbations during this phase. We show that our approach precisely matches with the so-called "separate universe approach" or "δN formalism" by studying a simple quadratic two-field potential.<br>text

This thesis considers the anonymously published Epistola de terrae motu and the question of its authorship. The authorship of this treatise was attributed to G. J. Rheticus by Reijer Hooykaas in a publication released in 1984; however, that attribution is not decisive. The first chapter introduces De terrae motu and is followed by a second chapter that contains a review of the relevant historiography relating to scholarship on Rheticus. The third chapter presents Rheticus’ biography. The fourth chapter considers the inconclusive reasoning for the attribution of authorship to Rheticus. The fifth and sixth chapters consider the environment of scriptural hermeneutics in the early modern period, both theoretically and with recourse to specific texts, respectively. The seventh chapter concludes this thesis with a synthesis of the arguments herein which ultimately indicate that it is conceivable that Rheticus wrote De terrae motu but an early seventeenth-century Catholic author is more likely.