Made available in DSpace on 2016-04-28T14:16:32Z (GMT). No. of bitstreams: 1 Fumikazu Saito.pdf: 10989609 bytes, checksum: 339ee2687abdfdc808fbb99663c1ebfb (MD5) Previous issue date: 2008-05-19 / Fundação de Amparo a Pesquisa do Estado de São Paulo / This work discusses the relationship between instrument and sensorial or perceptive experience in the light of Giambattista della Porta s natural magic and the 17th century natural philosophy. It points out to factors that made of the telescope a natural magic device, by approaching to the design of Galileo Galilei s instrument. Analysis is centered on De telescopio, De refractione optices parte libri novem and Magiae naturalis libri XX by Della Porta and Sidereus nuncius by Galileu, as primary sources. This study allowed to realize that the expansion of the visual capacity achieved through instruments and devices was not merely related to philosophical strategies that would lead to mistrust naked-eye observation or mathematization of seeing by 15th century linear perspective. Among other features involved in the change of views regarding the observation of nature, the recognition of the sharper visual perception achieved through instruments was also associated to natural magic s manipulation of seeing / Este estudo discute a relação do instrumento com a experiência sensória ou perceptiva sob a perspectiva da magia natural de Giambattista della Porta e da filosofia natural do século XVII. Aponta-se, desse modo, para os indícios que fizeram do telescópio um aparato de magia natural, dialogando com a concepção do instrumento de Galileu Galilei. Foram selecionados para análise o De telescopio, o De refractione optices parte libri novem e a Magiae naturalis libri XX de Della Porta e o Sidereus nuncius de Galileu, como fontes primárias. Por meio deste estudo, observou-se que a ampliação da capacidade visual, por meio de aparatos e instrumentos, não estava apenas relacionada a certas estratégias de natureza filosófica, que fizeram desacreditar na observação a olho nu, nem à matematização do olhar proposta pela perspectiva linear do século XV. Além de outros aspectos relacionados à mudança de atitude em relação à observação da natureza, o reconhecimento de uma percepção visual mais aguda, por meio de instrumentos, estava também relacionado com a proposta da magia natural de manipular o olhar

Submitted by Biblioteca do Instituto de Física (bif@ndc.uff.br) on 2017-07-14T19:20:36Z No. of bitstreams: 1 Marcel N Oliveira_Mestrado_UFF.pdf: 4519413 bytes, checksum: c433d3349c9b78949e508a919bf89ad8 (MD5) / Made available in DSpace on 2017-07-14T19:20:36Z (GMT). No. of bitstreams: 1 Marcel N Oliveira_Mestrado_UFF.pdf: 4519413 bytes, checksum: c433d3349c9b78949e508a919bf89ad8 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Um filamento solar entrou em erupção no dia 1 de Novembro de 2014, com início às 04:44 UT e uma duração de cerca de três horas, resultando em uma explosão solar (flare) do de classe C2.7. O flare foi associado com o desaparecimento súbito de um grande filamento. O filamento foi ejetado para o espaço, formando um núcleo de uma emissão de massa coronal (CME). A localização da explosão foi na região sudeste do sol (perto da borda oriental do sol), isto significa que a região não é geoefetiva. Uma tempestade de radiação, isto é, partículas energéticas solares (SEP) começaram a chegar à Terra em torno de 14:00 UT, atingindo a condição do nível S1 (menor) na escala NOAA de tempestades de radiação, em 2 de Novembro. Em coincidência com o início da tempestade de radiação S1 (SEP acima de 5 MeV), os telescópios Tupi localizados no IF-UFF, em Niterói – RJ, região que está localizada dentro da Anomalia do Atlântico Sul (SAA) detectou um excesso de múons, originados por partículas (prótons) relativísticas emitidas na explosão solar. Além disso, também foi encontrado em um aumento na intensidade de partículas observado no monitor de nêutrons localizado no Polo Sul. Isto significa que houve uma propagação transversal ao campo magnético interplanetário de partículas energéticas solares. No entanto, mostra-se que a difusão perpendicular sozinha não pode explicar estas observações, é necessária uma combinação com outros processos como uma velocidade muito alta, pelo menos de uma fração dos choques CME, perto do plano da eclíptica. / A solar filament erupted on November the 1st, 2014, started at 04:44 UT with a duration of about 3 hours, resulting in a solar flare of the type C2-7. The flare was associated with the sudden disappearance of a big filament. The filament was ejected to the space, forming the nucleus of a coronal mass ejection (CME). The explosion was localized in the southeast region of the sun (near sun’s oriental border), this means that the region is not geoeffective. A radiation storm i.e solar energetic particles (SEP) started to arrive on Earth around 14:00 UT, reaching the level S1 (minor) condition on the NOAA scale of radiation storms, on November the 2nd. Coinciding with the start of the S1 radiation storm (SEP above 5 MeV), the Tupi telescopes localized in IF-UFF, Niterói – RJ, region that is localized within the South Atlantic Anomaly (SAA) detected an excess of muons, originated from relativistic particles (protons) emitted on the solar explosion. Furthermore, an increase of the intensity of particles observed on the neutron monitor localized on the south pole. This means that a transversal, to the interplanetary magnetic field, propagation of solar energetic particles occurred. Nonetheless, is shown that the perpendicular diffusion alone can not explain this observations, a combination with other processes is necessary like a very high speed, of at least a fraction of the CME shocks, around the ecliptic plane.

Energy resolution characteristics of silicon surface barrier detector signals amplified by different preamplifiers and spectroscopic amplifiers have been studied. The characterization has been done using alpha particles from an 241Am source and spontaneous fission fragments from two Cf sources. The alpha and spontaneous fission activities of the sources have been measured and the isotopic compositions, ages, and initial activities of the two Cf sources have been calculated using the results from the activity measurements. 82.3% and 82.5% of the spontaneous fission activity of the two sources is found to originate from 252Cf. Heavy ion detection properties of two Si detector setups have been determined by measuring spontaneous fission fragments from one of the Cf sources in coincidence. The mass distribution of fission fragments is derived from the pulse spectra of the coincidence measurements. The conditions for future time resolution measurements have been established. Inquiries on commercially available ultra-thin Si detectors have been made. The purpose is to upgrade detector telescopes to lower the energy threshold of ΔE-ΔE-E identification of particles from neutroninduced nuclear reactions. Three manufacturers of Si detectors with thickness 20-25 µm and active area around 450 mm2 have been listed together with properties of the three offered detectors.

The BRIght Target Explorer (BRITE) constellation is revolutionary in the sense that the same scientific objectives can be achieved smaller (cm3 versus m3 ) and lighter (< 10kg versus 1, 000kg). It is a space astronomy mission, observing the variations in the apparent brightness of stars. The work presented herein focuses on the assembly, integration and test of the instrument used on-board six nanosatellites that form the constellation. The instrument is composed of an optical telescope equipped with a Charge Coupled Device (CCD) imager and a dedicated computer. This thesis provides a particular in-depth look into the inner workings of CCD. Methods used to characterize the instrument CCD in terms of its bias level stability, gain factor determination, saturation, dark current and readout noise level evaluation are provided. These methodologies are not limited to CCDs and they provide the basis for anyone who wishes to characterize any type of imager for scientic applications.

The BRIght Target Explorer (BRITE) constellation is revolutionary in the sense that the same scientific objectives can be achieved smaller (cm3 versus m3 ) and lighter (< 10kg versus 1, 000kg). It is a space astronomy mission, observing the variations in the apparent brightness of stars. The work presented herein focuses on the assembly, integration and test of the instrument used on-board six nanosatellites that form the constellation. The instrument is composed of an optical telescope equipped with a Charge Coupled Device (CCD) imager and a dedicated computer. This thesis provides a particular in-depth look into the inner workings of CCD. Methods used to characterize the instrument CCD in terms of its bias level stability, gain factor determination, saturation, dark current and readout noise level evaluation are provided. These methodologies are not limited to CCDs and they provide the basis for anyone who wishes to characterize any type of imager for scientic applications.

This report describes simulations of observations with the near-infrared high-resolution spectrometer SIMPLE that is proposed to the ESO telescope E-ELT. We simulate M4 and G2 stars with transiting Earth-like planets and the goal is to distinguish spectral features originating from the atmosphere of the exoplanet. Noise levels of different magnitudes are added to the simulations and the minimal signal-to-noise required for detection of the atmosphere is estimated. Our conclusion is that detection of atmospheric features looks promising using this setup.

This thesis provides background information on the Hobby-Eberly Telescope (HET), HET Dark Energy Experiment (HETDEX), Gough-Stewart platforms (GSP), the Prime Focus Instrument Package (PFIP) support structure, and the design methodology used to design said support structure. Each component is analyzed from the point of view of Professor Alex Slocum’s FRDPARRC design methodology. Each aspect of the design is shown to have been derived by following the steps of Slocum’s design method. Material selection, manufacturing techniques, and integration of off-the-shelf components into the support system are also discussed in reference to FRDPARRC. The assembly procedure for the PFIP structure is outlined. Finally, using specific examples from the detailed design, the FRDPARRC method itself is analyzed and its ability to drive innovation in design is evaluated. / text

Le LAT est l'instrument principal du satellite Fermi et permet d'étudier le ciel en rayons gamma de 20 MeV à plus de 300 GeV. Sa sensibilité accrue a permis l'augmentation du nombre de sources détectées dans le domaine des hautes énergies. Une partie importante de celles-ci n'a pas de contrepartie connue et une étude multi-longueur d'onde est nécessaire afin de comprendre l'origine du signal observé. Dans un premier temps, cette thèse présente l'étude morphologique et spectrale détaillée de la source non-identifiée HESS J1745--303, qui a été découverte dans le domaine gamma par l'expérience H.E.S.S. en 2006 puis analysée spécifiquement dans un article de 2008, à l'aide des données du LAT. Deux sources ponctuelles situées à une localisation proche de HESS J1745--303 sont présentes dans le catalogue à deux ans de données de Fermi (2FGL) mais une analyse dédiée de cette région est néanmoins nécessaire vu sa complexité. Elle est en effet localisée à ~1° du Centre Galactique et à moins de 0.5° du pulsar de la Souris, les deux sources les plus brillantes en gamma dans cette région. Les différents processus d'émission de photons sont présentés dans un second temps. Leurs simulations permettent d'effectuer une étude approfondie de l'origine de l'émission détectée aux hautes et très hautes énergies par le LAT et par H.E.S.S. L'émission de cette source reste en effet encore énigmatique de nos jours et une étude multi-longueur d'onde est effectuée afin de contraindre les modèles d'émission.

Receiver systems utilising planar technologies are prevalent in telescopes observing at radio to sub-millimetre wavelengths. Receiver components using planar technologies are generally smaller, have reduced mass and are cheaper to manufacture than waveguide-based alternatives. Given that modern-day detectors are capable of reaching the fundamental photon noise limit, increases in the sensitivity of telescopes are frequently attained by increasing the total number of detectors in the receivers. The development of components utilising planar technologies facilitates the demand for large numbers of detectors, whilst minimising the size, mass and manufacturing cost of the receiver. After a review and study of existing concepts in radio to sub-mm telescopes and their receivers, this thesis develops planar components that couple the radiation from the telescope's optics onto the focal plane. Two components are developed; a W- band (75-110 GHz) planar antenna-coupled flat mesh lens designed for the receiver of a Cosmic Microwave Background (CMB) B-mode experiment, and an L-band (1- 2 GHz) horn-coupled planar orthomode transducer designed for the receiver of the FAST telescope. The first developments of a planar antenna-coupled flat mesh lens are presented. The design is driven by the requirement to mitigate beam systematics to prevent pollution of the CMB B-mode signal. In the first instance, a waveguide-coupled mesh lens is characterised. The radiation patterns of the waveguide-coupled mesh lens have -3 dB beam widths between 26 and 19 degrees, beam ellipticity &lt;10%, and cross-polarisation.

Les sursauts gamma (GRBs pour "Gamma-Ray Bursts" en anglais) sont de brèves bouffées très énergétiques de rayonnement de haute énergie qui sont émises sur de courtes échelles de temps (fraction de seconde à plusieurs minutes). L'émission intense des sursauts gamma à haute énergie est supposée provenir d'un trou noir de masse stellaire nouvellement formé, accompagné d'un vent collimaté (i.e. un jet) se propageant à vitesse relativiste. L'émission est observée suivant deux phases successives, la phase prompte très erratique, et la phase de rémanence, moins lumineuse. Les deux instruments embarqués sur le satellite Fermi, le "Gamma-ray Burst Monitor" (GBM) et le "Large Area Telescope" (LAT), permettent d'étudier l'émission prompte des sursauts gamma sur une grande plage d'énergie (de ~10 keV à ~100 GeV). L'objectif principal de ma thèse est l'analyse et l'interprétation des propriétés spectrales et temporelles de l'émission prompte des GRBs observés par Fermi, en particulier avec les nouvelles données du LAT (Pass 8) qui ont été rendues publiques en juin 2015.La première partie de mon travail est une analyse spectrale résolue en temps de la phase prompte du sursaut GRB 090926A avec les données du GBM et du LAT. Mes résultats confirment avec un meilleur niveau de confiance la présence d'une cassure spectrale à ~400 MeV, qui est observée en coincidence avec un pic d'émission très court. Ils révèlent que cette atténuation spectrale est présente durant toute l'émission prompte du sursaut, et que l'énergie de cassure augmente jusqu'au GeV. L'interprétation de la cassure spectrale en termes d'absorption gamma ou de courbure naturelle du spectre d'émission Compton inverse (CI) dans le régime Klein-Nishina fournit des contraintes fortes sur le facteur de Lorentz du jet. Mes résultats conduisent en outre à des rayons d'émission R ∼10^14 cm qui sont compatibles avec une origine interne de l'émission du keV au GeV au-dessus de la photosphère du jet.La seconde partie de mon travail est une exploration du modèle de chocs internes développé par des collaborateurs à l'Institut d'Astrophysique de Paris (IAP). Ce modèle simule la dynamique du jet et les processus d'émission (synchrotron et CI) d'une population d'électrons accélérés aux chocs. J'ai simulé la réponse instrumentale de Fermi à un sursaut synthétique fourni par ce code numérique, et j'ai construit une fonction paramétrique qui peut être utilisée pour ajuster le modèle aux spectres de sursauts du keV au MeV. J'ai appliqué cette fonction avec succès à un échantillon de 64 sursauts brillants détectés par le GBM. J'ai aussi confronté le modèle de l'IAP au spectre d'émission prompte de GRB 090926A. Mes résultats montrent un bon accord, et j'ai identifié quelques pistes pour les améliorer. Les spectres synthétiques sont plus larges que tous les spectres dans l'échantillon du GBM. En conséquence, je discute brièvement quelques pistes de développements théoriques qui pourraient améliorer l'accord du modèle avec les observations, ainsi que des avancées observationnelles attendues dans le futur. / Gamma-Ray Bursts (GRBs) are very energetic and brief flashes of high-energy radiations which are emitted in a short time scale (fraction of a second to several minutes). The GRB bright emission is thought to be powered by a newly formed stellar-mass black hole that is accompanied by a collimated outflow (i.e. a jet) moving at a relativistic speed. The emission is observed as two successive phases: the highly variable “prompt” phase and the late and less luminous “afterglow” phase. The two instruments on board the Fermi space telescope, the Gamma-ray Burst Monitor (GBM) and the Large Area Telescope (LAT), allow the study of GRB prompt emission over a broad energy range (from ~10 keV to ~100 GeV). In June 2015, a new set of LAT data (Pass 8) was publicly released, which were generated using improved algorithms of reconstruction and classification of gamma-ray events. The main goal of my thesis is the analysis and interpretation of the spectral and temporal properties of the prompt emission phase of the GRBs observed by Fermi, especially using LAT Pass8 data.In the first part of my work, I performed a detailed time-resolved spectral analysis of the prompt phase of GRB 090926A with GBM and LAT data. My results confirm with a greater significance the spectral break at ∼400 MeV that is observed during a fast variability pulse, and they also reveal the presence of a spectral attenuation throughout the GRB prompt emission, as well as an increase of the break energy up to the GeV domain. I interpreted the spectral break in terms of gamma-ray absorption or as a natural curvature of the inverse Compton (IC) emission in the Klein-Nishina regime. Strong constraints on the jet Lorentz factor were obtained in both scenarios. My results lead also to emission radii R ∼10^14 cm, which are consistent with an internal origin of both the keV-MeV and GeV prompt emissions above the jet photosphere.The second part of my work is an exploration of the internal shock model that has been developed by collaborators at the "Institut d'Astrophysique de Paris" (IAP). This model simulates the GRB jet dynamics and the radiations (synchrotron and IC processes) from a population of shock-accelerated electrons. I simulated the response of the Fermi instruments to the synthetic GRB spectra provided by this numerical code. From these simulations, I built a new parametric function that can be used to fit the keV-MeV spectra of GRBs with the model. I applied successfully this function to a sample of 64 GBM bright GRBs. I confronted also the IAP model to the prompt emission spectrum of GRB 090926A. I obtained a relatively good agreement and I identified a couple of solutions that may improve it. The synthetic spectra are wider than any GRB spectra in the GBM sample. I present some theoretical developments that could improve the data-model agreement in the future, and I discuss possible advances from future GRB missions as well.