360 resultados para cosmologia


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Esta dissertação de mestrado analisará a expressão grega ta. stoicei/a tou/ ko,smou, “os elementos do mundo”, que ocorre na carta de Colossenses nos versículos 8 e 20 do segundo capítulo. Será feito um estudo exegético na perícope bíblica 2.8-3.4 da referida carta, bem como uma análise histórica especificamente do termo stoicei/a. O estudo desta expressão é importante para poder se compreender a filosofia colossense mencionada em Cl 2.8. A igreja cristã na cidade de Colossos estava inserida em um contexto social religioso sincrético. Esse sincretismo é percebido claramente em textos de magia como os Papiros Mágicos Gregos, muito comuns na região da Ásia Menor, a mesma onde a igreja colossense estava situada. O sincretismo religioso, envolvendo crenças judaicas e pagãs, reflete as bases dessa filosofia. O autor da carta aos Colossenses refuta a crença nos “elementos do mundo”, bem como a subserviência aos mesmos. Dentre outras crenças, acreditava-se que esses “elementos” poderiam influenciar os acontecimentos sobre a terra e o destino das pessoas. Questões que envolvem práticas acéticas, adoração a anjos e observância de calendário litúrgico, dão os contornos dessa filosofia. O autor da carta enfatiza o senhorio de Cristo, bem como as obras dele em favor dos cristãos colossenses, que proporcionavam a eles, segurança quanto a terem um bom destino. E, além disso, é assegurada uma liberdade aos cristãos colossenses que não podia lhes ser cerceada por quaisquer outras crenças religiosas. Então, as obras de Cristo, bem como o seu senhorio, são os principais argumentos utilizados pelo autor da carta, a fim de afirmar aos cristãos em Colossos que eles não precisam mais temer o destino e nem se submeter aos “elementos do mundo”.

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Index: vol. 10, pt. 1-2.

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Dark matter is a fundamental ingredient of the modern Cosmology. It is necessary in order to explain the process of structures formation in the Universe, rotation curves of galaxies and the mass discrepancy in clusters of galaxies. However, although many efforts, in both aspects, theoretical and experimental, have been made, the nature of dark matter is still unknown and the only convincing evidence for its existence is gravitational. This rises doubts about its existence and, in turn, opens the possibility that the Einstein’s gravity needs to be modified at some scale. We study, in this work, the possibility that the Eddington-Born-Infeld (EBI) modified gravity provides en alternative explanation for the mass discrepancy in clusters of galaxies. For this purpose we derive the modified Einstein field equations and find their solutions to a spherical system of identical and collisionless point particles. Then, we took into account the collisionless relativistic Boltzmann equation and using some approximations and assumptions for weak gravitational field, we derived the generalized virial theorem in the framework of EBI gravity. In order to compare the predictions of EBI gravity with astrophysical observations we estimated the order of magnitude of the geometric mass, showing that it is compatible with present observations. Finally, considering a power law for the density of galaxies in the cluster, we derived expressions for the radial velocity dispersion of the galaxies, which can be used for testing some features of the EBI gravity.

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Dark matter is a fundamental ingredient of the modern Cosmology. It is necessary in order to explain the process of structures formation in the Universe, rotation curves of galaxies and the mass discrepancy in clusters of galaxies. However, although many efforts, in both aspects, theoretical and experimental, have been made, the nature of dark matter is still unknown and the only convincing evidence for its existence is gravitational. This rises doubts about its existence and, in turn, opens the possibility that the Einstein’s gravity needs to be modified at some scale. We study, in this work, the possibility that the Eddington-Born-Infeld (EBI) modified gravity provides en alternative explanation for the mass discrepancy in clusters of galaxies. For this purpose we derive the modified Einstein field equations and find their solutions to a spherical system of identical and collisionless point particles. Then, we took into account the collisionless relativistic Boltzmann equation and using some approximations and assumptions for weak gravitational field, we derived the generalized virial theorem in the framework of EBI gravity. In order to compare the predictions of EBI gravity with astrophysical observations we estimated the order of magnitude of the geometric mass, showing that it is compatible with present observations. Finally, considering a power law for the density of galaxies in the cluster, we derived expressions for the radial velocity dispersion of the galaxies, which can be used for testing some features of the EBI gravity.

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Since long ago that the religious manifestations are considered important items in various social media. In this sense, we are interested in understanding the strong denominational plurality, and the emergence of new movements / events and forms of Christianity in Brazil, which therefore is a reflection of what happens in the rest of the globalized world. Such interest is covered by the assumption that religiosity and social media are built on mutual and interconnected way, which allows us to understand that social cosmology presents itself as a fertile space privileged and to verify the interactions pertaining to the binomial: religion and society. The Protestantism is divided into three main streams: Historical, Pentecostal and Neo-Pentecostal. Each current of Protestantism emerged to adapt to social cosmology of historical ages, from the Reformation to the present day, forming institutions with certain ethical and moral stances. In this sense, it is necessary to research and understand how the historical Protestant, Pentecostal and neo-Pentecostal were implanted in Brazil. From this we believe to be interesting problematize accurately the following: How have the processes of formation of strands / evangelical movements in Brazil? These movements are still holding their "classic robes" or hybreeding their borders? What are the modulations in the religious transit demonstrate that this probable hybridization? If there is, indeed, a hybridization between the Evangelical means, we can put it is provoked only by a logic of "market of symbolic goods of religion" in the world today? Nowadays, we are experiencing a period of change cosmological, from Modern to Postmodern (caosmológic). This last is therefore characterized by secularization, the fracture, the mutilation, the diversity of subjectivities. And thinking about is this "spirit of the times" we take as the main its theoretical references of this study, the Italian philosopher and thinker of postmodernity Gianni Vattimo featuring postmodernity with the cosmology of fragile / pensiero debole Thought and post-metaphysical, that is which enhances the appearance of more plural institutions and non-absolute. To do so, he makes use of the philosophies of German, Nietzsche and Heidegger. Finally, it must be said that this grounded theoretical framework, raise the hypothesis that the Protestantism tends to "injure anymore" by the influence of postmodern social episteme, providing thereby the emergence of a new hybrid framework has not yet nominated and can move between the three major currents of world Protestantism, with features in converged aspects of the same.

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Since long ago that the religious manifestations are considered important items in various social media. In this sense, we are interested in understanding the strong denominational plurality, and the emergence of new movements / events and forms of Christianity in Brazil, which therefore is a reflection of what happens in the rest of the globalized world. Such interest is covered by the assumption that religiosity and social media are built on mutual and interconnected way, which allows us to understand that social cosmology presents itself as a fertile space privileged and to verify the interactions pertaining to the binomial: religion and society. The Protestantism is divided into three main streams: Historical, Pentecostal and Neo-Pentecostal. Each current of Protestantism emerged to adapt to social cosmology of historical ages, from the Reformation to the present day, forming institutions with certain ethical and moral stances. In this sense, it is necessary to research and understand how the historical Protestant, Pentecostal and neo-Pentecostal were implanted in Brazil. From this we believe to be interesting problematize accurately the following: How have the processes of formation of strands / evangelical movements in Brazil? These movements are still holding their "classic robes" or hybreeding their borders? What are the modulations in the religious transit demonstrate that this probable hybridization? If there is, indeed, a hybridization between the Evangelical means, we can put it is provoked only by a logic of "market of symbolic goods of religion" in the world today? Nowadays, we are experiencing a period of change cosmological, from Modern to Postmodern (caosmológic). This last is therefore characterized by secularization, the fracture, the mutilation, the diversity of subjectivities. And thinking about is this "spirit of the times" we take as the main its theoretical references of this study, the Italian philosopher and thinker of postmodernity Gianni Vattimo featuring postmodernity with the cosmology of fragile / pensiero debole Thought and post-metaphysical, that is which enhances the appearance of more plural institutions and non-absolute. To do so, he makes use of the philosophies of German, Nietzsche and Heidegger. Finally, it must be said that this grounded theoretical framework, raise the hypothesis that the Protestantism tends to "injure anymore" by the influence of postmodern social episteme, providing thereby the emergence of a new hybrid framework has not yet nominated and can move between the three major currents of world Protestantism, with features in converged aspects of the same.

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The aim of this Thesis work is to study the multi-frequency properties of the Ultra Luminous Infrared Galaxy (ULIRG) IRAS 00183-7111 (I00183) at z = 0.327, connecting ALMA sub-mm/mm observations with those at high energies in order to place constraints on the properties of its central power source and verify whether the gas traced by the CO may be responsible for the obscuration observed in X-rays. I00183 was selected from the so-called Spoon diagnostic diagram (Spoon et al. 2007) for mid-infrared spectra of infrared galaxies based on the equivalent width of the 6.2 μm Polycyclic Aromatic Hydrocarbon (PAH) emission feature versus the 9.7 μm silicate strength. Such features are a powerful tool to investigate the contribution of star formation and AGN activity in this class of objects. I00183 was selected from the top-left region of the plot where the most obscured sources, characterized by a strong Si absorption feature, are located. To link the sub-mm/mm to the X-ray properties of I00183, ALMA archival Cycle 0 data in Band 3 (87 GHz) and Band 6 (270 GHz) have been calibrated and analyzed, using CASA software. ALMA Cycle 0 was the Early Science program for which data reprocessing is strongly suggested. The main work of this Thesis consisted in reprocessing raw data to provide an improvement with respect to the available archival products and results, which were obtained using standard procedures. The high-energy data consists of Chandra, XMM-Newton and NuSTAR observations which provide a broad coverage of the spectrum in the energy range 0.5 − 30 keV. Chandra and XMM archival data were used, with an exposure time of 22 and 22.2 ks, respectively; their reduction was carried out using CIAO and SAS software. The 100 ks NuSTAR are still private and the spectra were obtained by courtesy of the PI (K. Iwasawa). A detailed spectral analysis was done using XSPEC software; the spectral shape was reproduced starting from simple phenomenological models, and then more physical models were introduced to account for the complex mechanisms that involve this source. In Chapter 1, an overview of the scientific background is discussed, with a focus on the target, I00183, and the Spoon diagnostic diagram, from which it was originally selected. In Chapter 2, the basic principles of interferometry are briefly introduced, with a description of the calibration theory applied to interferometric observations. In Chapter 3, ALMA and its capabilities, both current and future, are shown, explaining also the complex structure of the ALMA archive. In Chapter 4, the calibration of ALMA data is presented and discussed, showing also the obtained imaging products. In Chapter 5, the analysis and discussion of the main results obtained from ALMA data is presented. In Chapter 6, the X-ray observations, data reduction and spectral analysis are reported, with a brief introduction to the basic principle of X-ray astronomy and the instruments from which the observations were carried out. Finally, the overall work is summarized, with particular emphasis on the main obtained results and the possible future perspectives.

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The aim of this thesis is to study the angular momentum of a sample of S0 galaxies. In the quest to understand whether the formation of S0 galaxies is more closely linked to that of ellipticals or that of spirals, our goal is to compare the amount of their specific angular momentum as a function of stellar mass with respect to spirals. Through kinematic comparison between these different classes of galaxies we aim to understand if a scenario of passive evolution, in which the galaxy’s gas is consumed and the star formation is quenched, can be considered as plausible mechanism to explain the transformation from spirals to S0s. In order to derive the structural and photometric parameters of galaxy sub-components we performed a bulge-disc decomposition of optical images using GALFIT. The stellar kinematic of the galaxies was measured using integral field spectroscopic data from CALIFA survey. The development of new original software, based on a Monte Carlo Markov Chain algorithm, allowed us to obtain the values of the line of sight velocity and velocity dispersion of disc and bulge components. The result that we obtained is that S0 discs have a distribution of stellar specific angular momentum that is in full agreement with that of spiral discs, so the mechanism of simple fading can be considered as one of the most important for transformation from spirals to S0s.

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Clusters of galaxies are the most massive and large gravitationally bounded systems in the whole Universe. Their study is of fundamental importance to constrain cosmological parameters and to obtain informations regarding various kind of emission in different wavebands. In particular, in the radio domain, beside the diffuse emission, the study is focused on the radio galaxies emission. Radio galaxies in clusters can have peculiar morphology, since they interact with the intracluster medium (ICM) in which they are embedded. Particularly, in this thesis we focused our attention on the so-called Narrow-Angle Tailed radio galaxies (NAT), which present radio jets that are bent at extreme angle, up to 90 degrees, from their original orientation. Some NAT show a narrow extended structure and the two radio tails are not resolved even with high resolution radio observations. An example is provided by the source IC310, in the Perseus Cluster, whose structure has been recently interpreted as due to Doppler boosting effects of a relativistic jet oriented at a small angle with respect to the line of sight. If the structure is due to relativistic effects, this implies that the jets are relativistic at about 400 kpc from the core, but this is in contrast with unified models, which predict that for low-power radio source (NAT are classified as FRI radio galaxies) the jets decelerate to sub-relativistic speed within a few kpc from the core. To investigate this scientific topic, in this thesis we have analyzed the innermost structure of a sample of eleven radio galaxies showing a very narrow NAT structure. We can conclude that the structure of these radio galaxies is different from that of IC310. These radio galaxies are indeed strongly influenced by environmental effects and are similar to classical NAT sources.

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Gli ammassi di galassie sono le strutture più grandi che possiamo osservare nell’Universo. La loro formazione deriva direttamente dalla crescita delle perturbazioni primordiali di densità e dal loro conseguente collasso gravitazionale indotto appunto dalla gravità. Gli ammassi di galassie sono molto importanti in Astrofisica in quanto possono essere considerati come dei laboratori per lo studio di molti aspetti fisici legati al gas, all’ICM e all’evoluzione delle galassie. Lo studio degli ammassi di galassie è molto importante anche per la Cosmologia in quanto è possibile effettuare delle stime sui parametri cosmologici ed ottenere dei vincoli sulla geometria dell’Universo andando a valutare la loro massa e la loro distribuzione nell’Universo. Diventa quindi fondamentale l’utilizzo di algoritmi che ci permettano di utilizzare i dati ottenuti dalle osservazioni per cercare ed individuare gli ammassi di galassie in modo tale da definire meglio la loro distribuzione nell’Universo. Le più recenti survey di galassie ci forniscono molteplici informazioni a riguardo delle galassie, come ad esempio la loro magnitudine in varie bande osservative, il loro colore, la loro velocità ecc. In questo lavoro abbiamo voluto testare la performance di un algoritmo Optimal Filtering nella ricerca degli ammassi di galassie utilizzando prima solo l’informazione della magnitudine delle galassie e successivamente anche l’informazione sul loro colore. Quello che abbiamo voluto fare, quindi, è stato valutare se l’utilizzo combinato della magnitudine delle galassie e del loro colore permette all’algoritmo di individuare più facilmente, e in numero maggiore, gli ammassi di galassie.

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The Standard Cosmological Model is generally accepted by the scientific community, there are still an amount of unresolved issues. From the observable characteristics of the structures in the Universe,it should be possible to impose constraints on the cosmological parameters. Cosmic Voids (CV) are a major component of the LSS and have been shown to possess great potential for constraining DE and testing theories of gravity. But a gap between CV observations and theory still persists. A theoretical model for void statistical distribution as a function of size exists (SvdW) However, the SvdW model has been unsuccesful in reproducing the results obtained from cosmological simulations. This undermines the possibility of using voids as cosmological probes. The goal of our thesis work is to cover the gap between theoretical predictions and measured distributions of cosmic voids. We develop an algorithm to identify voids in simulations,consistently with theory. We inspecting the possibilities offered by a recently proposed refinement of the SvdW (the Vdn model, Jennings et al., 2013). Comparing void catalogues to theory, we validate the Vdn model, finding that it is reliable over a large range of radii, at all the redshifts considered and for all the cosmological models inspected. We have then searched for a size function model for voids identified in a distribution of biased tracers. We find that, naively applying the same procedure used for the unbiased tracers to a halo mock distribution does not provide success- full results, suggesting that the Vdn model requires to be reconsidered when dealing with biased samples. Thus, we test two alternative exten- sions of the model and find that two scaling relations exist: both the Dark Matter void radii and the underlying Dark Matter density contrast scale with the halo-defined void radii. We use these findings to develop a semi-analytical model which gives promising results.

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Obscured AGN are a crucial ingredient to understand the full growth history of super massive black holes and the coevolution with their host galaxies, since they constitute the bulk of the BH accretion. In the distant Universe, many of them are hosted by submillimeter galaxies (SMGs), characterized by a high production of stars and a very fast consumption of gas. Therefore, the analysis of this class of objects is fundamental to investigate the role of the ISM in the early coevolution of galaxies and black holes. We present a multiwavelength study of a sample of six obscured X-ray selected AGN at z>2.5 in the CDF-S, detected in the far-IR/submm bands. We performed the X-ray spectral analysis based on the 7Ms Chandra dataset, which provides the best X-ray spectral information currently available for distant AGN. We were able to place constraints on the obscuring column densities and the intrinsic luminosities of our targets. Moreover, we built up the UV to FIR spectral energy distributions (SEDs) by combining the broad-band photometry from CANDELS and the Herschel catalogs, and analyzed them by means of an SED decomposition technique. Therefore, we derived important physical parameters of both the host galaxy and the AGN. In addition, we obtained, through an empirical calibration, the gas mass in the host galaxy and assessed the galaxy sizes in order to estimate the column density associated with the host ISM. The comparison of the ISM column densities with the values measured from the X-ray spectral analysis pointed out that the contribution of the host ISM to the obscuration of the AGN emission can be substantial, ranging from ~10% up to ~100% of the value derived from the X-ray spectra. The absorption may occur at different physical scales in these sources and, in particular, the medium in the host galaxy is an ingredient that should be taken into account, since it may have a relevant role in driving the early co-evolution of galaxies with their black holes.