Adaptive optics holds a fundamental role in the era of thirty meter class telescopes; this technology has gained such import that is incorporated into all first light instruments of both the upcoming E-ELT and TMT telescopes. Moreover, each of these telescopes are planning to use advanced forms of adaptive optics to exploit unprecedented scientific niches, such as Multi-Conjugate Adaptive Optics and Multi-Object Adaptive Optics. The complexity of these systems requires careful preliminary considerations, such as demonstration of the technology on existing telescopes and effective calibration procedures. In this thesis I address these two considerations through two different approaches. First, I demonstrate the use of the Multi-Object Adaptive Op- tics demonstrator RAVEN to gather high-resolution spectroscopy for the first time with this technology, and I identify some of the most metal-poor stars in the Galactic bulge to date. Secondly, I develop two focal plane wavefront sensing techniques to calibrate the internal aberrations of RAVEN and explore their applications to other adaptive optics systems.  I analyze spectra of individual stars in two Globular Clusters to establish infrared techniques that can be used with the RAVEN instrument. Detailed chemical abundances for five stars in NGC 5466 and NGC 5024, are presented from high-resolution optical (from the Hobby-Eberley Telescope) and infrared spectra (from the SDSS- III APOGEE survey). I find [Fe/H] = -1.97 ± 0.13 dex for NGC 5466, and [Fe/H] = -2.06 ± 0.13 dex for NGC 5024, and the typical abundance pattern for globular clusters for the remaining elements, e.g. both show evidence for mixing in their light element abundance ratios (C, N), and asymptotic giant branch contributions in their heavy element abundances (Y, Ba, and Eu). These clusters were selected to examine chemical trends that may correlate them with the Sgr dwarf galaxy remnant, but at these low metallicities no obvious differences from the Galactic abundance pattern are found. Regardless, I compare my results from the optical and infrared analyses to find that oxygen and silicon abundances determined from the infrared spectral lines are in better agreement with the other α-element ratios and with smaller random errors. Using the aforementioned infrared techniques, I derive the chemical abundances for five metal-poor stars in and towards the Galactic bulge from the H-band spectroscopy taken with RAVEN at the Subaru 8.2-m telescope. Three of these stars are in the Galactic bulge and have metallicities between -2.1 < [Fe/H] < -1.5, and high [α/Fe] ∼ +0.3, typical of Galactic disc and bulge stars in this metallicity range; [Al/Fe] and [N/Fe] are also high, whereas [C/Fe] < +0.3. An examination of their orbits suggests that two of these stars may be confined to the Galactic bulge and one is a halo trespasser, though proper motion values used to calculate orbits are quite uncertain. An additional two stars in the globular cluster M22 show [Fe/H] values consistent to within 1σ , although one of these two stars has [Fe/H] = -2.01 ± 0.09, which is on the low end for this cluster. The [α/Fe] and [Ni/Fe] values differ by 2, with the most metal-poor star showing significantly higher values for these elements. M22 is known to show element abundance variations, consistent with a multipopulation scenario though our results cannot discriminate this clearly given our abundance uncertainties. This is the first science demonstration of multi-object adaptive optics with high-resolution infrared spectroscopy, and we also discuss the feasibility of this technique for use in the upcoming era of 30-m class telescope facilities. Lastly, I develop two focal plane wavefront sensing techniques to calibrate the non-common path aberrations (NCPA) in adaptive optics systems. I first demonstrate these techniques in a detailed simulation of the future TMT instrument NFIRAOS. I then validate these techniques on an experimental bench subject to NFIRAOS-like wavefront errors. The two techniques are subsequently used to identify and correct the NCPA on both RAVEN and the NFIRAOS test-bench knowns as HeNOS. The application of these techniques is also explored on the VLT/SPHERE system to identify what is known as the ‘Low Wind Effect’ (LWE). I first quantify the LWE in simulation and then validate the technique on an experimental bench. I then estimate the LWE from on-sky data taken with the VLT/SPHERE adaptive optics system. Lastly, I apply my focal plane wavefront sensing techniques to estimate residual mirror co-phasing errors seen on Keck with the NIRC2 adaptive optics system data. I first demonstrate the ability of my techniques to quantify these errors in a simulation of Keck/NIRC2 data. I then apply their capabilities to estimate the mirror co-phasing errors of Keck with on-sky data. / Graduate

Following the foundation of aberration theory for rotationally symmetric optical systems established by Seidel, Schwarzschild, Burch, Conrady, Buchdahl, and in its most useful form H.H. Hopkins, Shack, Buchroeder, Thompson, and Rogers developed a vectorial form of the wave aberration theory that enables addressing optical systems without symmetry. In this research, a vectorial theory is utilized and extended for the alignment of two- and three-mirror astronomical telescopes, including the effects of pointing changes and astigmatic figure errors. Importantly, it is demonstrated that the vectorial form of aberration theory, also referred to as nodal aberration theory, not only provides valuable insights but also facilitates a quantitative description of the aberrations in optical systems without symmetry. Specifically, nodal aberration theory has been utilized to establish key insights into the aberration field response of astronomical telescopes to misalignments. Important nodal properties have been derived and discussed and the theoretical predictions have been validated with optical design software. It has been demonstrated that the removal of on-axis coma in some of the most common astronomical telescopes in use today directly leads to a constraint for one of the nodes for astigmatism to be located at the field center, which is exactly true for Cassegrain or Gregorian telescopes, and approximately true for Ritchey-Chretien (or aplanatic Gregorian) telescopes. These observations led to important conclusions concerning the alignment of astronomical telescopes. First, the correction of these telescopes on-axis for zero coma removes all misalignment induced aberrations only on-axis. Secondly, given that the image quality at the field center remains stigmatic in the presence of misalignments, for these telescopes non-zero astigmatism measured at the field-center directly reveals astigmatic mirror figure errors. Importantly, the effects of misalignments and astigmatic figure error can be clearly distinguished if present in combination, even in the presence of significant boresight errors. Having the possibility to clearly distinguish between misalignment and astigmatic mirror figure error provides an important prerequisite for the optimal operation of active/adaptive optics systems that are becoming standard in observatory class telescopes. Subsequent work on TMA telescopes revealed that even though TMAs are limited by fifth order aberrations in their nominal alignment state, third order nodal aberration theory provides accurate image quality predictions for misalignments and astigmatic figure (third order) effects in these optical systems. It has been demonstrated for the first time that analytical expressions can be devised that describe the characteristic misalignment induced aberration fields of any TMA telescope, leading to two main image quality degrading aberrations, field-constant coma and field-linear, field-asymmetric astigmatism. These new insights can be strategically leveraged in the development of alignment strategies for TMAs. The final part of this work analyzed how third and fifth order nodal aberration fields can be utilized in the alignment of wide-angle telescopes, with the specific example of the Large Synoptic Survey Telescope (LSST). In cooperation with the National Optical Astronomy Observatory (NOAO) an alignment strategy has been developed for the LSST (without camera) to expedite the commissioning of the telescope, providing for the first time analytical expressions for the computation of misalignment parameters in three-mirror telescopes, taking into account fabrication tolerances for the alignment of the tertiary mirror on the primary mirror substrate. Even though the discussion has been focused primarily on alignment strategies of astronomical telescopes, the methods and algorithms developed in this work can be equally applied to any imaging system.

Detection of earth-size exoplanets using the astrometric signal of the host star requires sub-microarcsecond measurement precision. One major challenge in achieving this precision using a medium-size (< 2-m) space telescope is the calibration of dynamic distortions. A diffractive pupil can be used to generate polychromatic diffraction spikes in the focal plane, which encode the distortions in the optical system and may be used to calibrate astrometric measurements. The first half of this dissertation discusses the design and construction of a laboratory to test this concept. The main components of the system are a high stability star simulator, a diffraction limited off-axis optical system, and the data reduction algorithms to obtain the distortion map calibration. Currently, the laboratory is operational and first tests of distortion measurements have been done validating this concept to improve the astrometric accuracy of a telescope. The second part of this dissertation describes the use of the multi-laser guide star (LGS) system available at the 6.5 m MMT telescope to characterize GLAO performance and advance Laser Tomography Adaptive Optics (LTAO) technology. The system uses five range-gated and dynamically refocused Rayleigh laser beacons to sense the atmospheric wavefront aberration. Corrections are then applied to the wavefront using the 336-actuator adaptive secondary mirror of the telescope. So far, the system has demonstrated successful control of ground-layer aberration over a field of view (FoV) substantially wider than is delivered by conventional adaptive optics, yielding reduction in the width of the on-axis point-spread function from 1.07" to < 0.2" in H band. Both techniques can be combined to improve the astrometric accuracy of ground based telescopes, especially when using Multi-Conjugated Adaptive Optics (MCAO). A diffractive pupil can be used to calibrate the distortions induced by multiple Deformable Mirrors (DM), which is the main limitation to use this kind of AO system for high precision astrometric measurements.

L'observation du milieu interstellaire est très importante aux fréquences mm / (sub) mm / Thz pour comprendre comment se forment les étoiles et les planètes. De telles observations dépendent des récepteurs hétérodynes. Ces instruments atteignent une résolution spectrale très élevée en convertissant un signal haute fréquence à une fréquence plus basse. Dans un récepteur hétérodyne, le signal collecté est superposé sur un signal artificiel, bien connu, monochromatique, généré par l'oscillateur local (OL), donc ce signal artificiel est plus-ou-moins la fréquence du signal du ciel. Le mélangeur produit le signal de la fréquence du battement. Cette fréquence est équivalente à la différence entre le OL et la fréquence du signal du ciel. Ainsi, le signal du ciel est traduit à une fréquence plus basse, pour qu'il soit facile à amplifier et détecter. Habituellement, les récepteurs hétérodynes ont seulement un pixel spatial avec de nombreux canaux en fréquences. Notre objectif est de développer des réseaux de centaines de pixels. Pour faire cela, certains composants de l'hétérodyne doivent être repensés radicalement, tels que l'antenne de réception et le diviseur de faisceau OL. En effet, l'antenne réceptrice est généralement constituée d'une antenne à double fentes sur une lentille, ou d'une antenne cornet. Par contre, ces antennes ne sont pas les meilleurs choix pour des réseaux de nombreux pixels car elles doivent être usinées et montées individuellement. Au lieu de cela, il est commode de développer des structures planaires qui peuvent être facilement produites toutes ensembles. En particulier, nous avons conçu et simulé des réseaux d'antennes patch, de réseaux de transmission, et de plaques de zone. Le réseau d'antennes patch consiste d'un réseau de patchs métalliques reliés par une ligne microruban et séparés du plan de masse par un substrat diélectrique. Cette configuration profite du facteur du réseau pour réduire la largeur de faisceau du signal collecté. Cependant, nos simulations nous montrent que la bande RF des réseaux d'antennes patch est étroite. Pour cette raison, nous avons analysé la possibilité d'utiliser une autre solution : le réseau de transmission. C'est un réseau de plusieurs cellules qui déphase une onde afin de transformer son front de phase de forme planaire en forme sphérique. Le but de la matrice de transmission est de focaliser le faisceau collecté vers une antenne et mélangeur à double fentes. La thés démontre qu'un effet de focalisation satisfaisant est atteint sur une ligne. Nous avons fabriqué un tel réseau de transmission et l'avons testé en laboratoire. En raison des petites dimensions de quelques millimètres, ces tests sont difficiles à réaliser. Au sein de l'erreur de mesure, la conception et les simulations sont cohérentes. Une troisième option (d'une lentille planaire) a été étudiée dans la thèse : la plaque de zone. C'est un type particulier de réseau de transmission qui ne présente que deux déphasages de 0 ° et 180 °. Le plaque de zone focalise bien, mais est peu efficace. La dernière partie de la thèse introduit un type de diviseur de faisceau particulier qui permet une division du faisceau du signal OL vers un réseau de quatre mélangeurs très serrés. Diviser le faisceau avec des angles suffisamment petits est très difficile avec les réseaux de Fourier et Dammann classiques. Pour cette raison la méthode que nous avons proposée pour concevoir un tel diviseur est très novatrice. En effet, il permet la formation de motifs de faisceaux de forme arbitraire, qui ne sont pas limités par les ordres de diffraction. Les simulations montrent des efficacités allant jusqu'à 80% qui sont très bonnes en comparaison avec les réseaux classiques. En résumé, dans cette thèse, j'ai essayé plusieurs moyens radicalement différents pour simplifier les récepteurs hétérodynes et ouvrir la voie aux grandes matrices hétérodynes avec des centaines de pixels. / The observation of the interstellar medium is very important at mm/(sub)mm/THz frequencies to understand how stars and planets form. Generally such observations rely on heterodyne receivers. These are instruments that achieve very high spectral resolution by down converting a high frequency signal towards a lower frequency one. In a heterodyne receiver the incoming signal is superimposed onto an artificial, well-known, monochromatic signal generated by the local oscillator (LO), chosen to be close to the frequency of the sky signal. The mixer produces the beat frequency signal. It has a frequency equivalent to the difference between the LO and sky signal frequency. Thus the sky signal is translated to a lower frequency, and it is easier to amplify and detect. Usually heterodyne receivers have only one spatial pixel with many frequency channels. Some prototypes have been realized recently with few pixels. Our objective is to develop arrays of hundreds of pixels. In order to do that, some components which compose the heterodyne receiver must be radically rethought, such as the receiving antenna and the LO beam divider.Indeed the receiving antenna generally consists of a double slot antenna on a lens, or a horn antenna. Such antennas are not the best choice for arrays of many pixels since they have to be machined and mounted individually. Instead it is convenient to develop planar structures which can be easily produced in bulk in a single process. In particular we designed and simulated arrays of patch antennas, transmit-arrays and zone plates. The array of patch antennas consists of an array of metallic patches connected via a microstrip line and separated from the ground plane by a dielectric substrate. This configuration takes advantage of the array factor to reduce the beamwidth of the incoming signal in place of the lens. However our simulations showed the array of patch antennas to be quite narrowband for a general purpose application, and quite difficult to realize. For this reason we also analyzed the possibility to use another solution such as the transmit-array. It is an array of several cells which provide a certain phase shift to an incoming wave in order to transform its phase front from planar to spherical. The purpose of the transmit-array is to focus the incoming beam towards a double slot antenna and a mixer placed below it. The simulations showed that a good focusing effect can be reached on a line. We fabricated such a transmit-array and tested it in the laboratory. Because of the small dimensions of a few millimeters these tests are difficult to carry out. Within the measurement error design and simulations are consistent. A third option of a planar lens was studied in the thesis: the zone plate. This is a particular kind of transmit-array which presents only two phase shift of 0° and 180°. The zone plates focus well, but are unfortunately not very efficient.The final part of the thesis introduces a particular kind of beam divider which allows beam splitting of the LO signal towards an array of four very closely packed mixers. To split the beam with such small relative angles is very difficult with the classical Fourier and Dammann grating, for this reason the method we proposed to design such a beam divider is very innovative. Indeed it allows the forming of arbitrary shaped beam patterns, which are not limited by the diffraction orders. Simulations show efficiencies up to 80% which are very good in comparison with classical gratings.In summary in this thesis I have tried several radically different approaches to simplify heterodyne receivers and made a first step towards for large heterodyne arrays with hundreds of pixels.

Orientador: Cláudio Luiz Carvalho / Banca: Fernanda Catia Bozelli / Banca: Hermes Adolfo de Aquino / Resumo: De acordo com pesquisas em ensino de ciências, nos últimos tempos, os alunos de forma geral, não compreendem e não desenvolvem as tarefas sobre os conceitos básicos de ciências, como por exemplo, relacionar um tema de Física com os acontecimentos rotineiros do dia a dia, assim como relacioná-lo com a Química ou Geografia. Uma possível hipótese está no fato de que o ambiente escolar frequentado pelos alunos, atualmente, está desconexo com os interesses e curiosidades que eles possuem em aprender. Estes interesses estão ligados apenas a conceitos imediatistas. Esta geração de alunos que está se moldando é conhecida como "geração tecnológica". As simples experimentações em si realizadas em salas de aulas não refletem no real aprendizado para que os alunos desenvolvam competências e habilidades na elaboração de saberes científico. Os conteúdos são apenas direcionados para cumprir currículos em espaços de tempo cada vez mais reduzidos. Pela fundamentação teórica de David Ausubel, que relaciona a questão de materiais representativos e significativos no processo de ensino aprendizagem, foi proposta, nesta pesquisa, a discussão dos conceitos de Astronomia, em formatos de oficinas, na qual os alunos foram incentivados a criar o próprio conhecimento de forma construtivista por meio da metodologia mediadora na relação com os outros saberes como a Matemática, Geografia, História, Física incentivando a interdisciplinaridade. Os resultados obtidos nas oficinas foram gravados e transformado... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In agreement of recent science education research, recently, in general, students cannot understand and also can not develop their stuff about basic science concepts, such as make the relationship between Physics and something that happen day-by-day either relation with chemistry or geography. A possible hypothesis can be the fact of the scholar ambient could be disconnected from the interest and curiosities that they should be to learn. These interests are connected just only with immediatist concepts. The students generation that is coming is called "Technological generation". The experiments did in classroom have not been enough to improve their scientific skills. The subjects are just specifically used to fulfill curricula in a short period of time (and this time have been reduced constantly or periodically or frequently). By the theoretical basis of David Ausubel, that related representative and significative materials in the teaching/ learnt process was proposed, in this Project, the discussion of about Astronomy concepts using workshop format, In which students were encouraged to create their own knowledge in a constructivist way through the mediator methodology in relation to other knowledge such as Mathematics, Geography, History, Physics encouraging interdisciplinarity. The results obtained in the workshops were recorded and transformed in media material that it can be shared in web. This material is being used for reference source and studies, providing free access... (Complete abstract click electronic access below) / Mestre

The main focus of this thesis is the investigation of an interesting new population of massive passively evolving galaxies found at high redshifts. We use a sample of these galaxies at redshifts 1<z<2 drawn from the Gemini Deep Deep Survey sample and measure their structural parameters based on the Hubble Space Telescope imaging in the rest frame visible and ultraviolet wavelength range. Our analysis shows that a fraction of these systems are very compact, with effective radii of R_e<1 kpc, even when observed in rest frame visible light. The average size of these objects is 2-5 times smaller than the typical size of an early-type galaxy of similar mass found locally. We combine the results from our morphological analysis with data from published spectroscopic samples of quiescent systems with known structural parameters. Analysis of these data for galaxies over the redshift range 0<z<2.5 shows that passively evolving galaxies are continuously and gradually growing in size. We also find smooth evolution of the stellar mass density within the central kiloparsec of these systems. The stellar mass density grows by a factor of 3 from z=0 to z~2.5. None of the models proposed to drive the structural evolution of early-type objects can explain all the observed aspects of this process. Because these massive compact galaxies have such small angular sizes, future studies of these systems will benefit from adaptive optics. In order to compile a large statistical sample of these objects suitable for adaptive optics follow-up, we first need to find a large number of targets with nearby bright natural guide stars. As a first step in this process, we describe the properties of a set of one square degree regions of the sky we have located that have a rare combination of high stellar surface density and low levels of extinction. We demonstrate that the adaptive optics-related properties of these fields are in some cases orders of magnitude better than those of existing deep fields.

The main focus of this thesis is the investigation of an interesting new population of massive passively evolving galaxies found at high redshifts. We use a sample of these galaxies at redshifts 1<z<2 drawn from the Gemini Deep Deep Survey sample and measure their structural parameters based on the Hubble Space Telescope imaging in the rest frame visible and ultraviolet wavelength range. Our analysis shows that a fraction of these systems are very compact, with effective radii of R_e<1 kpc, even when observed in rest frame visible light. The average size of these objects is 2-5 times smaller than the typical size of an early-type galaxy of similar mass found locally. We combine the results from our morphological analysis with data from published spectroscopic samples of quiescent systems with known structural parameters. Analysis of these data for galaxies over the redshift range 0<z<2.5 shows that passively evolving galaxies are continuously and gradually growing in size. We also find smooth evolution of the stellar mass density within the central kiloparsec of these systems. The stellar mass density grows by a factor of 3 from z=0 to z~2.5. None of the models proposed to drive the structural evolution of early-type objects can explain all the observed aspects of this process. Because these massive compact galaxies have such small angular sizes, future studies of these systems will benefit from adaptive optics. In order to compile a large statistical sample of these objects suitable for adaptive optics follow-up, we first need to find a large number of targets with nearby bright natural guide stars. As a first step in this process, we describe the properties of a set of one square degree regions of the sky we have located that have a rare combination of high stellar surface density and low levels of extinction. We demonstrate that the adaptive optics-related properties of these fields are in some cases orders of magnitude better than those of existing deep fields.

This thesis presents an engineering project measuring the effective wavelength of the CHARA Classic beam combiner on the CHARA Array. Knowing the actual effective wavelength of light observed is very important because that value is necessary for determining astrophysical parameters of stars. Currently, the value used for CHARA Classic data comes from a model of the system and is based on numbers published by the manufacturer of the filter; it is not derived from measurements done on the system directly. We use two data collection methods to observe standard stars of different spectral types and calculate the wavelength of light recorded by the instrument for each star. We find the best estimate of the effective wavelength for the CHARA Classic K′-band configuration to be 2.138±0.003μm, a 0.56% decrease from the previously adopted value of 2.150μm. Our result establishes the first estimate of the uncertainty in the effective wavelength.

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