Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 180-192).

Thesis (Ph. D.)--Carleton University, 1988. / Also available in electronic format on the Internet.

Thesis (M.S.)--Ball State University, 2009. / Title from PDF t.p. (viewed on June 07, 2010). Includes bibliographical references (p. [46]).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 73-74).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 137-142).

Depuis la première détection d’une planète extrasolaire autour d’une étoile de type solaire par Mayor et Queloz (1995), plus de 3000 planètes ont été découvertes. La découverte de planètes de type terrestre et la recherche de biomarqueurs dans leur atmosphère sont parmi les principaux objectifs de l'astronomie du XXIeme siècle. Nous nous tournons vers la découverte et la caractérisation des planètes situées dans la zone habitable de leur étoile hôte.La méthode des vitesses radiales (VRs) consiste à mesurer le mouvement réflexe de l'étoile induit par des planètes en orbite. D'autre part, grâce à la photométrie, on peut mesurer la diminution de flux reçu lors du passage d'une planète entre l'étoile ciblée et notre télescope : Il s'agit alors d'un transit. Ces techniques sont complémentaires pour mieux comprendre les systèmes extrasolaires. Cependant, pour atteindre les précisions nécessaires à la détection de Terres ou super-Terres, il est nécessaire de concevoir des instruments très stables, de comprendre les effets systématiques dus à l'atmosphère et tenter de les corriger.La recherche de planètes orbitant autour des étoiles de faibles masses permet d’atteindre dès aujourd'hui des planètes telluriques dans la zone habitable. En effet, en gardant tout autre paramètre égal, le mouvement réflexe (et donc l’amplitude de la variation VR) sera plus grand. De même, un transit sera plus profond si l’étoile centrale est une naine M que pour une étoile de type solaire. De plus, ces étoiles ont une plus faible luminosité que les étoiles de type solaire. Il en résulte que les planètes dans la zone habitable ont des périodes orbitales plus courtes (~50 jours pour les naines M contre ~360 jours pour des étoiles de type solaire).Cette thèse s'inscrit dans une démarche de détections et de caractérisations de planètes en zone habitable de naines M. Pour cela, j'ai observé des naines M avec le spectrographe HARPS, permettant la découverte ou la caractérisation de 24 planètes, qui pourront servir à constituer ou préciser les catalogues de suivi photométriques.En particulier, le projet ExTrA vise à utiliser la photométrie pour détecter des transits en utilisant une nouvelle méthode : la spectrophotométrie différentielle. Elle permet d'améliorer la qualité des courbes de lumière en s'affranchissant d'effets systématiques causés par l'atmosphère. J'introduis l'un d'eux : l'extinction atmosphérique de second ordre, aussi appelé "effet de couleur" et le simule pour la première fois en fonction de divers paramètres d'observations (des conditions atmosphériques aux étoiles ciblés).Je formalise ensuite la technique de spectrophotométrie et simule le gain apporté par la résolution spectrale sur la précision photométrique. Ces simulations prennent en compte les conditions atmosphériques les plus impactantes pour l'effet de couleur (la masse d'air, la quantité de vapeur d'eau) mais également le type d'étoile ciblé (température, gravité, activité) et la résolution spectrale (R<4000).Enfin, il n'existait pas de méthodes numériques spécifiques au projet ExTrA pour traiter les données de spectrophotométrie. Avec l'objectif de corriger les effets systématiques restants dans les courbes de lumière tout en ajustant d'éventuels transits, j'ai développé un nouvel algorithme et j'en expose les premiers résultats. / Since the first detection of an extrasolar planet orbiting a Sun-like star by Mayor and Queloz (1995), more than 3000 have been discovered. Discovering telluric planets and searching for biomarkers in their atmospheres are among the main objectives of the 21st century. Hence, our interest is focused on finding and characterising planets located in the habitable zone of their host star.On one hand, the method known as radial velocities (RV) consists in the measure of the star’s reflex motion induced by orbiting planets. On the other hand, thanks to photometry, we can measure the drop of flux when a planet transits in front of its host star. These techniques are complementary to better understand extrasolar systems. However, in order to reach the precisions necessary to detect an Earth-like planet or a super-Earth, we need very stable instruments as well as the understanding and removal of earth’s atmosphere systematic effects.Searching planets orbiting low mass stars, we already have access to telluric planets in the habitable zone. Indeed, everything else being equal, a lower mass of the host star implies a larger reflex motion, and thus a larger RV amplitude. A transit will be deeper if the central star is a M dwarf compared to a Sun-like star. Moreover, the lower luminosity of M dwarfs implies shorter orbital periods from planets in the habitable zone (~50 days against ~360 days, for M dwarfs compared to solar-type stars, respectively).In this context, this thesis aims to improve the detection and caracterisation of planets in the habitable zone of M dwarfs. I observed some of these stars with the HARPS spectro- graph, leading to the discovery or the caracterisation of 24 planets, which helps us building or precising catalogues of photometric follow-up.In particular, the ExTrA project uses photometry to detect transits using a brand new method : differential spectrophotometry. It improves the light curves quality eliminating sys- tematic effets caused by earth’s atmosphere. I present one these systematics, second order atmospheric extinction also know as color effect, and simulate it for the first time in function of observations parameters (from atmosphere conditions to target and comparison stars).Then, I formalise the technique of spectrophotometry and simulate the gain brought by the addition of spectral resolution to photometric precision. These simulations take in account the atmospheric conditions affecting the color effet (airmass, precipitate water vapor) but also the type of the stars (temperature, gravity, spots), and the spectral resolution (R<4000).Lastly, there were no numerical methods for the treatment of ExTrA’s data at the be- ginning of this work. I developped a new algorithm aiming to correct systematics using the spectral dimension while finding and fitting transits in light curves. I expose the first results obtained from simulations and photometric tests of ExTrA.

The Jupiter Trojan asteroids are minor bodies that orbit 60 degrees before and 60 degrees behind Jupiter. Because these orbits are stable over the lifetime of the Solar System, the properties of these objects may inform us about the conditions under which the Solar System formed. We present BVRI photometry for 110 of the intrinsically brightest and presumably largest members of the L4 and L5 Jupiter Trojans. We use a new principal color component derived by Chatelain et al. (2016) that is indicative of taxonomic types relevant to the Jupiter Trojan asteroids. We find that 83% of the largest Jupiter Trojans are consistent with a D-type classification, while 17% show shallower slopes more consistent with X-type and C-type classifications. We show the L4 and L5 populations to be taxonomically indistinguishable at large sizes, as well as include findings about certain objects that have resulted from these data. Specifically, multi-filter light curves for twelve objects show signs of V-I color variation in as many as two thirds of these objects, and our richest datasets allow for the determination of phase curves and shapes for some asteroids including a new shape model and pole solution for (1173) Anchises. Our goal is to use this study to shed light on these fascinating objects and to place the Trojans in context in the larger Solar System.

The bulk of the stellar growth over cosmic time is dominated by IR-luminous galaxies at cosmic noon (z = 1-2), many of which harbor a hidden active galactic nucleus (AGN). We use state-of-the-art infrared color diagnostics, combining Spitzer and Herschel observations, to separate dust-obscured AGNs from dusty star-forming galaxies (SFGs) in the CANDELS and COSMOS surveys. We calculate 24 mu m counts of SFGs, AGN/star-forming "Composites," and AGNs. AGNs and Composites dominate the counts above 0.8 mJy at 24 mu m, and Composites form at least 25% of an IR sample even to faint detection limits. We develop methods to use the Mid-Infrared Instrument (MIRI) on JWST to identify dust-obscured AGNs and Composite galaxies from z similar to 1-2. With the sensitivity and spacing of MIRI filters, we will detect >4 times as many AGN hosts as with Spitzer/IRAC criteria. Any star formation rates based on the 7.7 mu m PAH feature (likely to be applied to MIRI photometry) must be corrected for the contribution of the AGN, or the star formation rate will be overestimated by similar to 35% for cases where the AGN provides half the IR luminosity and similar to 50% when the AGN accounts for 90% of the luminosity. Finally, we demonstrate that our MIRI color technique can select AGNs with an Eddington ratio of lambda(Edd) similar to 0.01 and will identify AGN hosts with a higher specific star formation rate than X-ray techniques alone. JWST/MIRI will enable critical steps forward in identifying and understanding dust-obscured AGNs and the link to their host galaxies.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1975. / Bibliography: leaves 69-70. / M.S.

For 20 years now, gravitational microlensing observations towards the Galactic bulge have provided us with a wealth of information about the stellar and planetary content of our Galaxy, which is inaccessible via other current methods. This thesis summarises work on two research topics that arose in the context of exoplanetary microlensing, but we take a step back and consider ways of increasing our understanding of more fundamental phenomena: firstly, stellar microlenses in our Galaxy that were stereoscopically observed and, secondly, the morphological variety of binary-lens light curves. In autumn 2008, the ESA Rosetta spacecraft surveyed the Galactic bulge for microlensing events. With a baseline of ∼1.6 AU between the spacecraft and ground observations, significant parallax effects can be expected. We develop a photometry pipeline to deal with a severely undersampled point spread function in the crowded fields of the Galactic bulge, making use of complementary ground observations. Comparison of Rosetta and OGLE light curves provides the microlens parallax π[subscript{E}] , which constrains the mass and distance of the observed lenses. The lens mass could be fully determined if future proper motion measurements were obtained, whereas the lens distance additionally requires the determination of the source distance. In the second project, we present a detailed study of microlensing light curve morphologies. We provide a complete morphological classification for the case of the equal-mass binary lens, which makes use of the realisation that any microlensing peak can be categorised as one of only four types: cusp-grazing, cusp-crossing, fold-crossing or fold-grazing. As a means for this classification, we develop a caustic feature notation, which can be universally applied to binary lens caustics. Ultimately, this study aims to refine light curve modelling approaches by providing an optimal choice of initial parameter sets, while ensuring complete coverage of the relevant parameter space.