In my PhD, I advanced the scientific exploration of the Next Generation Transit Survey (NGTS), a ground-based wide-field survey operating at ESO’s Paranal Observatory in Chile since 2016. My original contribution to knowledge is the development of novel methods to 1) estimate NGTS’ yield of planets and false positives; 2) disentangle planets from false positives; and 3) accurately characterise planets. If an exoplanet passes (transits) in front of its host star, we can measure a periodic decrease in brightness. The study of transiting exoplanets gives insight into their size, formation, bulk composition and atmospheric properties. Transit surveys are limited by their ability to identify false positives, which can mimic planets and out-number them by a hundredfold. First, I designed a novel yield simulator to optimise NGTS’ observing strategy and identification of false positives (published in Günther et al., 2017a). This showed that NGTS’ prime targets, Neptune- and Earth-sized signals, are frequently mimicked by blended eclipsing binaries, allowing me to quantify and prepare strategies for candidate vetting and follow-up. Second, I developed a centroiding algorithm for NGTS, achieving a precision of 0.25 milli-pixel in a CCD image (published in Günther et al., 2017b). With this, one can measure a shift of light during an eclipse, readily identifying unresolved blended objects. Third, I innovated a joint Bayesian fitting framework for photometry, centroids, and radial velocity cross-correlation function profiles. This allows to disentangle which object (target or blend) is causing the signal and to characterise the system. My method has already unmasked numerous false positives. Most importantly, I confirmed that a signal which was almost erroneously rejected, is in fact an exoplanet (published in Günther et al., 2018). The presented achievements minimise the contamination with blended false positives in NGTS candidates by 80%, and show a new approach for unmasking hidden exoplanets. This research enhanced the success of NGTS, and can provide guidance for future missions.

Made available in DSpace on 2016-04-28T20:39:56Z (GMT). No. of bitstreams: 1 Peggy Coelho Carvalho.pdf: 501518 bytes, checksum: 6149c62f1458e0b29d66c0c53c49c3ac (MD5) Previous issue date: 2008-12-19 / This work aims to investigate some functions of silence on the psychoanalytic pratice. In his psychoanalytic space, where the core of the work is talking, dialoguing, the silent experiences can upset the analyst s capacity of observation and apprehension of the psychic reality, since some observable elements become unavailable. The adopted method is my own poetic style and, through the poetic bond established with the reader, I propose to expand the knowledge, reflections and comprehension of silent situations. I make an analogy with the musical technique of counterpoint using trhee principal and simultaneous events, or voices: Beethoven s, John Milton s and my own, interrelated around the theme of silence during all the narrative. My hypothesis is that it is possible that the being/not being can reveal and/or hide itself through silence, pregnant of mental pain. In this trajectory, I did not come across the silence by itself, but with the process of silence and, at the end, I found the silence as mental pain and pleasure / O objetivo deste trabalho é investigar algumas funções do silenciar na clínica psicanalítica. Neste espaço psicanalítico, no qual o cerne do trabalho é o conversar, o dialogar, as experiências silenciosas podem dificultar a capacidade de observação e apreensão da realidade psíquica por parte do analista, uma vez que alguns elementos observáveis ficam indisponíveis. O método adotado é o meu próprio estilo poético e, através do vínculo poético estabelecido com o leitor, proponho expandir nossos conhecimentos, nossas reflexões e compreensão sobre as situações silenciosas. Faço analogia com a técnica contrapontística musical no sentido de que utilizo três principais acontecimentos simultâneos, ou, vozes: de Beethoven, de John Milton e a minha própria voz que se inter-relacionam em torno do tema do silenciar durante toda a narrativa. Minha hipótese é a de que seja possível que o ser/não ser possa revelar-se e/ou ocultar-se através do silêncio, pregnante de dor mental. Nesta trajetória, fui deparando não com o silêncio, coisa-em-si, mas com o processo de silenciar e, ao final, encontrei o silenciar como dor e prazer mentais