We determine the mass scale of Planck galaxy clusters using gravitational lensing mass measurements from the Cluster Lensing And Supernova survey with Hubble (CLASH). We have compared the lensing masses to the Planck Sunyaev-Zeldovich (SZ) mass proxy for 21 clusters in common, employing a Bayesian analysis to simultaneously fit an idealized CLASH selection function and the distribution between the measured observables and true cluster mass. We used a tiered analysis strategy to explicitly demonstrate the importance of priors on weak lensing mass accuracy. In the case of an assumed constant bias, b(SZ), between true cluster mass, M-500, and the Planck mass proxy, M-PL, our analysis constrains 1 - b(SZ) = 0.73 +/- 0.10 when moderate priors on weak lensing accuracy are used, including a zero-mean Gaussian with standard deviation of 8% to account for possible bias in lensing mass estimations. Our analysis explicitly accounts for possible selection bias effects in this calibration sourced by the CLASH selection function. Our constraint on the cluster mass scale is consistent with recent results from the Weighing the Giants program and the Canadian Cluster Comparison Project. It is also consistent, at 1.34 sigma, with the value needed to reconcile the Planck SZ cluster counts with Planck's base Lambda CDM model fit to the primary cosmic microwave background anisotropies.

In this paper I examine the existence of God through a focus on the cosmological argument as it ispresented here. My aim is to show that this argument provides support for the existence of God. To do this I examine that which I call the three steps of the cosmological argument: the first step being the accepting of the world as an ordered something, the second step being the ultimate question why this ordered something is there to begin with and the third step being that of God viewed as the only plausible answer. I argue that the ultimate question’s claim for an ultimate answer ought to be accepted due to the inability of individual things to explain the mere existence and order of things in general, which implies that the explanation for existence and order as such is to be searched beyond those things. Regarding the third step I argue that there has to be something rather than noting and that this something is to be viewed as something living due to the orderly nature of the world. From this I, finally, argue in favor of the explanatory value of a necessary being - i.e. God.

<p> In our search for an understanding of Old English cosmological conceptions we discover that the creation myth is central to the mysteries of the Christian faith, and that the Greek and Latin authors' interpretations of creation, known as "Hexaemera", provide much that is vital and influential to Old English poetic cosmology. My purpose in this dissertation is two-fold. The first is to provide for the Old English biblically-based poems an informing context of Greek and Latin hexaemeral writings drawn mainly from the Fathers of the Church. The second is to examine three Old English texts on creation and paradise as set against the background of the Mediterranean hexaemeral tradition. That a definite and complex accumulation of hexaemeral writings existed from the early patristic era through the Old English period (ca. A.D. 100-750) is confirmed by the wide variety of treatises, tractates, sermons, poems and hymns, assertive and didactic literary genres all revealing one major purpose -- the demonstration of intelligible order in the universe which is to be perceived through a vision of God's wisdom in creation.</p> <p> From this immense body of traditions about creation and paradise emerges a pattern which suggests to us the hypothesis that the Old English Christian poets, whose access to a broad range of such writings has been established, pondered and incorporated the hexaemeral features and conventions while adding their own variations to the creation theme. An important corollary to this hypothesis is that the Old English accounts of creation and paradise were influenced by an elaborate, lettered, and learned tradition which deserves special critical emphasis. Recent scholars have stressed the need for a comprehensive study of the potentialities of allusion in Old English poems to traditional Christian allegorical and tropological interpretations, as well as a study of the scholarly habits of perception which distinguished the monastic and ecclesiastical writings of the Middle Ages. This thesis is intended to fill a small aspect of this need in its exploration of the lettered traditions of creation which preceded and existed alongside Anglo-Saxon civilization.</p> <p> In order to develop this thesis I have categorized its two parts, respectively, as the patristic and poetic traditions. Part One offers an inquiry into the exegetical treatment of creation and paradise revealed in the Fathers, the Christian Latin poets, and related sources. The exploration is not intended to be comprehensive but representative in a critical mode directed towards illuminating our understanding of certain seminal concepts from which radiated further interpretations of creation in the Old English poetic canon. The figural levels of meaning perceived by patristic authors in such archetypal symbols as the primordial ocean, the green plain and golden groves of Eden, the luminaries of day and night, the fire and hail, snow and vapour of creation, contribute to our understanding of the Old English moulding of creation myths.</p> <p> In Part Two, the critical scope of the study focusses in three separate chapters on the creation :features of the Junius Genesis A and Christ and Satan, and the paradisal elements in the Exeter Phoenix. Equipped with a knowledge of the main features of the Mediterranean hexaemeral tradition, we are enabled to perceive the divergent treatment of creation themes in the relevant Old English texts. The intricacies of Christian exegesis can amplify our appreciation of the more concise Old English poetic hexaemeral in which the major emphasis is on tradition drawn from late classical antiquity, pagan Germanic concepts, and· biblical and patristic imagery. This assertion is not to imply that the Old English poetic texts merely present successive interpretations of creation and paradise without adding any new dimension. The hexaemeral tradition in the imaginations of the Old English poets loses the rigid character of dogma and develops into a vision of the world as cosmopoesy.</p> <p> The boundaries of investigation in this thesis are necessarily limited. I have selected a scope of study within the main documentable collection of traditions which aided in shaping Old English cosmogonic mythology. Throughout the study I argue for the significance of, and the indispensable need for, knowledge of Christian traditions in the area of Old English hexaemeral writings which constitute mythopoeic or imaginative literature in contrast to the homiletic character of influential patristic doctrine.</p> / Thesis / Doctor of Philosophy (PhD)

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Made available in DSpace on 2014-12-17T15:14:50Z (GMT). No. of bitstreams: 1 FranciscoES.pdf: 1953348 bytes, checksum: d700754d09d0b7966901ab6cbebb4085 (MD5) Previous issue date: 2008-11-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Recent astronomical observations (involving supernovae type Ia, cosmic background radiation anisotropy and galaxy clusters probes) have provided strong evidence that the observed universe is described by an accelerating, flat model whose space-time properties can be represented by the FriedmannRobertsonWalker (FRW) metric. However, the nature of the substance or mechanism behind the current cosmic acceleration remains unknown and its determination constitutes a challenging problem for modern cosmology. In the general relativistic description, an accelerat ing regime is usually obtained by assuming the existence of an exotic energy component endowed with negative pressure, called dark energy, which is usually represented by a cosmological constant ? associated to the vacuum energy density. All observational data available so far are in good agreement with the concordance cosmic ?CDM model. Nevertheless, such models are plagued with several problems thereby inspiring many authors to propose alternative candidates in the relativistic context. In this thesis, a new kind of accelerating flat model with no dark energy and fully dominated by cold dark matter (CDM) is proposed. The number of CDM particles is not conserved and the present accelerating stage is a consequence of the negative pressure describing the irreversible process of gravitational particle creation. In order to have a transition from a decelerating to an accelerating regime at low redshifts, the matter creation rate proposed here depends on 2 parameters (y and ??): the first one identifies a constant term of the order of H0 and the second one describes a time variation proportional to he Hubble parameter H(t). In this scenario, H0 does not need to be small in order to solve the age problem and the transition happens even if there is no matter creation during the radiation and part of the matter dominated phase (when the ? term is negligible). Like in flat ACDM scenarios, the dimming of distant type Ia supernovae can be fitted with just one free parameter, and the coincidence problem plaguing the models driven by the cosmological constant. ACDM is absent. The limits endowed with with the existence of the quasar APM 08279+5255, located at z = 3:91 and with an estimated ages between 2 and 3 Gyr are also investigated. In the simplest case (? = 0), the model is compatible with the existence of the quasar for y > 0:56 whether the age of the quasar is 2.0 Gyr. For 3 Gyr the limit derived is y > 0:72. New limits for the formation redshift of the quasar are also established / Observa?c~oes astron?micas recentes (envolvendo supernovas do tipo Ia, anisotropias da radia??o c?smica de fundo e aglomerados de gal?xias) sugerem fortemente que o Universo observado ? descrito por um modelo cosmol?gico plano e acelerado, cujas propriedades do espa?o-tempo podem ser representadas pela m?trica de Friedmann-Robertson-Walker (FRW). Entretanto, a natureza ou mecanismo respons?vel pela acelera??o permanece desconhecida e sua determina??o constitui o problema mais candente da Cosmologia moderna. Em cosmologias relativ?sticas, um regime acelerado ? usualmente obtido supondo a exist?ncia de uma componente ex?tica de energia com press?o negativa, denominada energia escura, cuja representa??o te?rica mais simples ? uma constante cosmol?gica ?, usualmente associada com a densidade de energia do v?cuo. Todas as observa??es conhecidas est?o de acordo com o chamado modelo de concordancia c?smica (ACDM). No entanto, tais modelos apresentam v?rios problemas te?ricos e tem inspirado muitos autores a proporem candidatos alternativos para representar a energia escura no contexto relativ?stico. Nesta tese, propomos um novo tipo de modelo plano, acelerado e sem energia escura, que ? completamente dominado pela mat?ria escura fria (CDM). O n?mero de part?culas de mat?ria escura n?o ? conservado e o atual est?gio acelerado ? uma consequ?ncia da press?o negativa descrevendo o processo irrevers?vel de cria??o gravitacional de mat?ria. Para ocorrer uma transi??o de um regime desacelerado para outro acelerado em baixos redshifts, a taxa de cria??o de mat?ria proposta aqui depende de 2 par?metros (y e ?): o primeiro deles identifca um termo constante da ordem de H0 enquanto o segundo especifica uma varia??o proporcional ao parametro de Hubble H(t). Neste cen?rio, H0 n?o precisa ser pequeno para resolver o problema da idade e a transi??o ocorre mesmo quando n?o existe cria??o de mat?ria durante a era da radia??o e parte da era da mat?ria (quando o termo ? ? desprez?vel). Tal como nos modelos ?CDM planos, os dados de supernovas tipo Ia distantes podem ser ajustados com um ?nico par?mero livre. Al?m disso, neste cen?rio n?o h? o problema da coincid?ncia c?smica existente nos modelos dirigidos pela constante cosmol?gica. Os limites oriundos da exist?ncia do quasar APM 08279+5255, localizado em z = 3:91, e com idade estimada entre 2 e 3 bilh?es de anos s?o tamb?m investigados. No caso mais simples (? = 0), o modelo ? compat?vel com a exist?ncia do quasar para y > 0; 56 se a idade do quasar for 2 bilh?es de anos. Para 3 bilh?es de anos o limite obtido ? y > 0; 72. Novos limites para o redshift de forma??o do quasar s?o tamb?m estabelecidos

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-12T14:56:03Z No. of bitstreams: 1 thiagomorallesdeabreu.pdf: 433339 bytes, checksum: dc2019985b911c7c131a86a07cac34de (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-15T13:36:51Z (GMT) No. of bitstreams: 1 thiagomorallesdeabreu.pdf: 433339 bytes, checksum: dc2019985b911c7c131a86a07cac34de (MD5) / Made available in DSpace on 2016-08-15T13:36:51Z (GMT). No. of bitstreams: 1 thiagomorallesdeabreu.pdf: 433339 bytes, checksum: dc2019985b911c7c131a86a07cac34de (MD5) Previous issue date: 2016-06-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Na presente dissertação é apresentada uma revisão detalhada de modelos cosmológicos, incluindo a dinâmica de perturbações cosmológicas lineares para dois modelos que desempenham interesse do ponto de vista de possíveis aplicações. Todo material discutido é oriundo da literatura recente e não se apresenta elementos originais. Entretanto, o conhecimento desses modelos abre uma possibilidade de extensões que estão agora sob discussão e desenvolvimento. De início é feita uma sucinta exposição do Modelo Cosmológico Padrão, que pode ser associado com o modelo FLRW (Friedmann-Lemaître-Robertson-Walker). Este último descreve um Universo em expansão marcado pela homogeneidade e isotropia em grande escala. Após isso discute-se o modelo com fluido cósmico composto por gás relativístico reduzido, mais conhecido pela sigla RRG, do inglês "reduced relativistic gas". A equação de estado do modelo RRG tem uma correspondência bem próxima ao modelo de gás de partículas massivas com energias cinéticas relativísticas. Considera-se ainda as perturbações cosmológicas em torno do modelo RRG de fundo plano, homogêneo e isotrópico. Por fim, segue-se a discussão sobre a possibilidade de incluir perturbações na constante gravitacional G e na constante cosmológica Λ, no ramo do modelo motivado por correções semiclássicas. / In this thesis we present a detailed review of some cosmological models, including the theory of linear cosmological perturbations for two distinct models which represent certain interest from the point of view of possible applications. All presented material comes from the recent literature and does not include original elements. However, the knowledge of these models opens a possibility of extensions which are now under discussion and development. At first it is presented a brief review of the Standard Cosmological Model, which can be associated with FLRW model (Friedmann-Lemaître-Robertson-Walker). The latter describes an expanding Universe marked by homogeneity and isotropy on a large scale. After that we discuss the model composite by a cosmic fluid described by reduced relativisticgas,betterknownbytheacronymRRG(reducedrelativisticgas). Theequation of state of the RRG model has a very close match to the model of gas of massive particles with relativistic kinetic energies. We consider the cosmological perturbations around the background of flat, homogeneous and isotropic RRG-based model. After that follows the discussion of the possibility of including perturbations of the gravitational constant G and the cosmological constant Λ within the model motivated by semiclassical corrections.

This thesis contributes to the field of dark energy and observational cosmology. We have investigated possible direction dependent systematic signal and non-Gaussian features in the supernovae (SNe) Type Ia data. To detect these effects we propose a new method of analysis. Although We have used this technique on SNe Ia data, it is quite general and can be applied to other data sets as well. SNe Ia are the most precise known distance indicators at the cosmological distances. Their constant peak luminosity(after correction) makesthem standard candles and hence one can measure the distances in the universe using SNe Ia. This distance measurement can determine various cosmological parameters such as the Hubble constant, various components of matter density and dark energy from, the SNe Ia observations. Recent SNe Ia observations have shown that the expansion of the universe is currently accelerating. This recent acceleration is explained by invoking a component in the universe having negative pressure and is termed as dark energy. It can be described by a homogeneous and isotropic fluid with the equation of state P = wρ, where w is allowed to be negative. A constant(Λ) in the Einstein equation(known as cosmological constant) can explain the acceleration, in the fluid model it can be modeled with w = -1. Other models of dark energy with w = -1 can also explain the acceleration, however the precise nature of this mysterious component remains unknown. Although there exist a wide range of dark energy models, cosmological constant provides the simplest explanation to the acceleration of the expansion of the Universe. The equation of state parameter w has been investigated by recent surveys but the results are still consistent with a wide range of dark energy models. In order to discriminate among various cosmological models we need an even more precise measurement of distance and error bars in the SNe Ia data. From the central limit theorem we expect Gaussian errors in any experiment that is free from systematic noise. However in astronomy we do not have a control over the observed phenomena and thus can not control the systematic errors (due to some physical processes in the Universe) in the observed data. The only possible way to deal with such data is by using appropriate statistical techniques. Among these systematic features the direction dependent features are more dangerous ones since they may indicate a preferred direction in the Universe. To address the issue of direction dependent features we have developed a new technique(Δ statistic henceforth) which is based on the extreme value theory. We have applied this technique to the available high-z SNe Ia data from Riess et al.(2004)and Riess et al.(2007). In addition we have applied it to the HST data from HST key project for H0 measurement. Below we summarize the material presented in the thesis. Chapter wise summary of the thesis In the first chapter we present an introductory discussion of the various basic cosmological notions eg. Cosmological Principle (CP), observational evidence in support of CP and departures from it, distance measures and large scale structure. The observed departures from the CP could be present due to the systematic errors and/or non-Gaussian error bars in the data. We discuss the errors involved in the measurement process Basics of statistical techniques : In the next two chapters we discuss basics of the statistical techniques used in this thesis and extreme value theory. Extreme value theory describes how to calculate the distribution of extreme events. The simplest of the distributions of the extremes is known as the Gumbel distribution. We discuss features of the Gumbel distribution since it is used extensively in our analysis. Δ statistic and features in the SNe data : In the fourth chapter we derive Δ statistic and apply it to the SNe Ia data sets. An outline of the Δ statistic is as follows : a) We define a plane which cuts the sky into hemispheres. This plane will divide the data into two subsets, one in each hemisphere. b) Now we calculate the χ2 in each hemisphere for an FRW universe assuming a flat geometry. c) The difference of χ2 in the two hemisphere is calculated and maximized by rotating the plane. This maximum should follow the Gumbel distribution. Since it is difficult to calculate the analytic form of Gumbel distribution we calculate it numerically assuming Gaussian error bars. This gives the theoretical distribution for the above calculated maximum of difference of χ2 . The results indicate that GD04 shows systematic effects as well non-Gaussian features while the set GD07 is better in terms of systematic effects and non-Gaussian features. Non-Gaussian features in the H0 data : HST key project measures the value of Hubble constant at the level of 10% accuracy, which requires precise measurement of the distances. It uses various methods to measure distance for instance SNe Ia, Tully-Fisher relation, surface-brightness fluctuations etc. In the fifth chapter we apply Δ statistic to the HST Key Project data in order to check the presence of non-Gaussian and direction dependent features. Our results show that although this data set seems to be free of direction dependent features, it is inconsistent with the Gaussian errors. Analytic Marginalization : The quantities of real interest in cosmology are ΩM and ΩΛ, Hubble constant could in principle be treated as a nuisance parameter. It would be useful to marginalize over the nuisance parameter. Although it can be done numerically using Bayesian method, Δ statistic does not allow it. In chapter six we propose a method to marginalize over H0 analytically. The χ2 in this case is a complicated function of errors in the data. We compare this analytic method with the Bayesian marginalization method and results show that the two methods are quite consistent. We apply the Δ statistic to the SNe data after the analytic marginalization. Results do not change much indicating the insensitivity of the direction de-pendent features to the Hubble constant. A variation to the Δ statistic: As has been discussed earlier that, it is difficult to calculate the theoretical distribution of Δ in general. However if the parent distribution follows certain conditions it is possible to derive the analytic form for the Gumbel distribution for Δ. In the seventh chapter we derive a variation to the Δ statistic in a way that allows us to calculate the analytic distribution. The results in this case are different from those presented earlier, but they confirm the same direction dependence and non-Gaussian features in the data.

During the 1980s, it was frequently claimed that spatial patterns of archaeological and contemporary settlements were closely related to the social nature of the societies which had created and modelled them (Hietala 1984; Hillier & Hanson 1984). Despite a decade of alternative claims, such theories are still widely accepted although in many cases the emphasis has shifted from economic factors to symbolic or social ones. The presence of a class-based social system is one of the major characteristics of Iranian society during the Sasanian era (224-651 CE). This social system was based upon the official religion of Sasanians - Zoroastrianism - and had a major impact on most aspects of Iranian society during this period. The far-reaching impact of this social system on architectural space and urban infrastructure is clearly representative of a class-based society. The collapse of the Sasanian world, accelerated by Arab invasions (641 CE), severely reduced the dominance of Zoroastrianism within Iran, heralding a fundamental change in the social life of its people. These changes, accompanied by the acceptance of a new religion, have been the focus of several researchers over the last decades (Kennedy 2001). In contrast to Sasanian society, Early Islamic social structure was characterised as one of equality and its urban forms as ones with little differentiation as typified by Medina (Zarrinkub 1993). The aim of this dissertation is to test the above assumptions and models with reference to a single urban site - the city of Barn. Selected due to its Pre-Islamic and Islamic occupations, its excellent state of preservation allows a full testing of the above assumptions through archaeological analysis. The results of this research indicate a continuation of patterns of Sasanian space and society into the Islamic period. In addition, the space and society of Bam, documented in this research, provides an important step towards a further understanding of the social and spatial organisation of Sasanian and Early-Islamic cities, as well as providing a foundation for additional research in this field.

<p>Type Ia supernovae can be used as distance indicators for probing the expansion history of the Universe. The method has proved to be an efficient tool in cosmology and played a decisive role in the discovery of a yet unknown energy form, dark energy, that drives the accelerated expansion of the Universe. The work in this thesis addresses the nature of dark energy, both by presenting existing data, and by predicting opportunities and difficulties related to possible future data.</p><p>Optical and infrared measurements of type Ia supernovae for different epochs in the cosmic expansion history are presented along with a discussion of the systematic errors. The data have been obtained with several instruments, and an optimal method for measuring the lightcurve of a background contaminated source has been used. The procedure was also tested by applying it on simulated images.</p><p>The future of supernova cosmology, and the target precision of cosmological parameters for the proposed SNAP satellite are discussed. In particular, the limits that can be set on various dark energy scenarios are investigated. The possibility of distinguishing between different inverse power-law quintessence models is also studied. The predictions are based on calculations made with the Supernova Observation Calculator, a software package, introduced in the thesis, for simulating the light propagation from distant objects. This tool has also been used for investigating how SNAP observations could be biased by gravitational lensing, and to what extent this would affect cosmology fitting. An alternative approach for estimating cosmological parameters, where lensing effects are taken into account, is also suggested. Finally, it is investigated to what extent strongly lensed core-collapse supernovae could be used as an alternative approach for determining cosmological parameters.</p>