Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

This thesis presents a multiwavelength analysis, from the infrared to the microwave, of the young, forming stars in the Auriga-California Molecular Cloud and a first look at the disks they host and their potential for forming planetary systems. At the beginning of this thesis, Auriga-Cal had only recently been identified as one contiguous cloud with its distance placing it within the Gould Belt of nearby star-forming regions (Lada et al. 2009). This thesis presents the largest body of work to date on Auriga-Cal's star formation and disk population. Auriga-Cal is one of two nearby giant molecular clouds (GMCs) in the Gould Belt, the other being the Orion A molecular cloud. These two GMCs have similar mass (~10^5 Msolar), spatial scale (~80 pc), distance (~450 pc), and filamentary morphology, yet the two clouds present very different star formation qualities and quantities. Namely, Auriga-Cal is forming far fewer stars and does not exhibit the high-mass star formation seen in Orion A. In this thesis, I present a census of the star forming objects in the infrared with the Spitzer Space Telescope showing that Auriga-Cal contains at least 166 young stellar objects (YSOs), 15-20x fewer stars than Orion A, the majority of which are located in the cluster around LkHalpha 101, NGC 1529, and the filament extending from it. I find the submillimetre census with the James Clerk Maxwell Telescope, sensitive to the youngest objects, arrives at a similar result showing the disparity between the two clouds observed in the infrared continues to the submillimetre. Therefore the relative star formation rate between the two clouds has remained constant in recent times. The final chapter introduces the first study targeted at the disk population to measure the formation potential of planetary systems around the young stars in Auriga-Cal. The dust thermal emission at cm wavelengths is observed to measure the relative amounts of cm-sized grains, indicative of the grain growth processes that take place in disks and are necessary for planet formation. For a subsample of our targets, we are able to measure the spectral slope in the cm to confirm the thermal nature of the observed emission that we detect and characterize the signature of grain growth. The sensitivity of our observations probes masses greater than the minimum mass solar nebula (MMSN), the disk mass required to form the Solar System. We detect 19 disks, representing almost a third of our sample, comparable to the numbers of disks in other nearby star-forming regions with disks masses exceeding the MMSN, suggesting that the disk population in Auriga-Cal possesses similar planet formation potential as populations in other clouds. Confirmation of this result requires future observations with mm interferometry, the wavelength regime where the majority of statistics of disks has been measured. / Graduate

We report contrast measurements of a sodium resonance guide star against the daylight sky when observed through a tuned magneto-optical filter (MOF). The guide star was created by projection of a laser beam at 589.16 nm into the mesospheric sodium layer and the observations were made with a collocated 1.5-m telescope. While MOFs are used with sodium light detecting and ranging systems during the day to improve the signalto- noise ratio of the measurements, they have not so far been employed with laser guide stars to drive adaptive optics (AO) systems to correct atmospherically induced image blur. We interpret our results in terms of the performance of AO systems for astronomy, with particular emphasis on thermal infrared observations at the next generation of extremely large telescopes now being built. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)

Hydrogen gas evaporating from the atmosphere of the hot-Neptune GJ436b absorbs over 50% of the stellar Lya emission during transit. Given the planet's atmospheric composition and energy-limited escape rate, this hydrogen outflow is expected to entrain heavier atoms such as C and O. We searched for C and Si in the escaping atmosphere of GJ436b using far-ultraviolet Hubble Space Telescope COS G130M observations made during the planet's extended H I transit. These observations show no transit absorption in the C II 1334,1335 angstrom and Si III 1206 angstrom lines integrated over [-100, 100] km s(-1), imposing 95% (2 sigma) upper limits of 14% (C II) and 60% (Si III) depth on the transit of an opaque disk and 22% (C II) and 49% (Si III) depth on an extended highly asymmetric transit similar to that of H I Ly alpha. C+ is likely present in the outflow according to a simulation we carried out using a spherically symmetric photochemical-hydrodynamical model. This simulation predicts an similar to 2% transit over the integrated bandpass, consistent with the data. At line center, we predict the C II transit depth to be as high as 19%. Our model predicts a neutral hydrogen escape rate of 1.6 x 10(9) g s(-1) (3.1 x 10(9) g s(-1) for all species) for an upper atmosphere composed of hydrogen and helium.

Approved for public release; distribution is unlimited / Design Center of the Naval Postgraduate School. The objective of this simulator is to provide on-the-ground simulation of the dynamics and control of spacecraft for high precision Acquisition, Tracking and Pointing applications associated with space based laser relay. The required initial attitude determination accuracy for the Bifocal Relay Mirror test-bed is 10 æ-radians. Normally, in laboratories where very high initial attitude knowledge is required, actual (space qualified) star trackers are incorporated into the testbed design. This is not possible at NPS as the laboratory does not have a skylight to allow visual access to the stars, and the photosensitive nature of many of the experiments would make such an opening inconvenient. Since it is critical to the operation of the testbed to provide accurate attitude knowledge, a substitute system was required. The present thesis documents the development of a new attitude sensor capable of providing attitude information within the required 10æ-radians (within a field of view of the order of 1 deg). The concepts leading up to the final design, the testing and selection of the equipment used in the final configuration, and a detailed explanation of how the final system calibration was performed are discussed in detail. / Lieutenant, United States Navy

Em 2005, Carolino e colaboradores isolaram uma fração neurotóxida de Averrhoa carambola (carambola) que foi capaz de apresentar sintomas em ratos e camundongos e foi chamada de AcTx. Acredita-se que o aminoácido denominado caramboxina esteja presente nesta fração e seja o metabólito secundário responsável por envenenamento pela ingestão da fruta em pacientes com insuficiência renal crônica. Apesar da estrutura da caramboxina ter sido elucidada por análises espectrométricas, a síntese deste composto visando caracterização estrutural e análise biológica ainda não havia sido realizada. Assim o objetivo deste trabalho foi investigar a síntese total da caramboxina visando sua caracterização estrutural e análise biológica dos compostos obtidos. Quatro rotas foram propostas, três das quais fizeram uso de reagentes organometálicos. Aquela que não fez uso de reagentes organometálicos foi a que se mostrou mais eficiente. / In 2005, Carolino and co-workers isolated a neurotoxic fraction of Averrhoa carambola (star fruit) that was able to cause seizures in rats and mice and was named AcTx. It is believed that the amino acid caramboxine, present in this fraction, is one of the secondary metabolites responsible for poisoning by fruit intake by patients with chronic renal failure. Despite its structure has been elucidated by spectrometric analysis, the synthesis of this compound aiming structural characterization and biological evaluation has not been still accomplished. Thus, the objective of this project was the total synthesis of caramboxina aiming their structural characterization and biological testing of the compounds obtained. Four routes have been proposed and investigated, three of them using organometallic reagents. The route that didn\'t use organometallic intermediates appeared to be the most efficient.

iPTF15dtg is a supernova (SN) Type Ic (lacking hydrogen and helium in its spectrum) with a light curve indicating that it is the result of a massive star explosion. Taddia et al. (2016) suggested that the progenitor star was a Wolf-Rayet (WR) star that previously suffered strong mass loss. More recent observations show that the SN light curve did not decline as expected, indicating the existence of an additional power source. One possibility is a magnetar, a hyper-magnetic neutron star capable of injecting its rotational energy into the light curve during relevant time scales. This bachelor thesis adds previously unpublished data to the iPTF15dtg light curve and compares simple semi-analytical models to rule out a radioactive scenario and discuss the possibility of a magnetar as the primary source of luminosity.

Religious elements are not uncommon in the field of popular culture, especially regarding movies, and the Star Wars series have implemented all sorts of different religious themes and religious symbolisms, almost as a sort of religious melting pot. This work, however, seeks to isolate and focus on a singular religious tradition. This essay aims to examine if, and what kinds of Christian elements are present in the first Star Wars trilogy. To determine what kind of religious and Christian elements that are present in the source material, which consist of the three original Star Wars films, episode IV through VI. The films were analyzed by using a hermeneutic theory and method, which would allow an interpretation of elements in the films which later could be considered religious and directly Christian, by connecting them to direct and indirect connotations in the Bible and Christian theology like that of Martin Luther. The results of the analysis show a few different kinds of Christian elements to be found in the first three movies. The results consist of: Names and symbols, Christian thematic in scenes and three overarching themes, salvation, Luke Skywalker as a messiah’s character, and different interpretations of the Force. An example of the results is regarding Martin Luther and sola fide and how that connection can be made to Star Wars. In the scene where this connection is made, we see our protagonist Luke Skywalker, using faith, and faith alone do destroy the Death Star, thereby redeeming not only himself but also the rebel alliance, which in turn can be likened as a symbol for the resurrection of Christ.

What drives the transition of galaxies from the disc dominated, star forming blue cloud to the elliptical dominated, quiescent red sequence? What role does the morphology, central supermassive black hole and galaxy environment play in this transition? I have attempted to answer these questions by using Bayesian statistics to infer a simple star formation history (SFH) describing the time, t_q, and exponential rate, τ, that quenching occurs in a galaxy. I use both the optical and NUV photometry of a galaxy in order to infer the posterior distribution of its SFH across the two dimensional [t_q, τ] parameter space. I then utilise the Galaxy Zoo 2 morphological classifications to obtain a morphology weighted, combined population distribution across each quenching parameter for a sample of galaxies. I apply this method across the blue cloud, green valley and red sequence of a sample of 126,316 galaxies and find a clear difference between the quenching timescales preferred by smooth and disc weighted populations, with three major routes through the green valley dominated by smooth (rapid rates, attributed to major mergers), intermediately classified (intermediate rates, attributed to galaxy interactions) and disc morphologies (slow rates, attributed to secular evolution). I hypothesise that morphological changes occur in systems which have undergone quenching with an exponential rate, τ < 1.5 Gyr, in order for the evolution of galaxies in the green valley to match the ratio of smooth to disc galaxies observed in the red sequence. I repeat this SFH analysis for a sample of 1,244 Type 2 AGN host galaxies and find statistical evidence for recent, rapid quenching, suggesting that this may be caused by AGN feedback. However I find that rapid quenching rates cannot account for all the quenching across the AGN host population; slow quenching rates, attributed to secular evolution, are also significant in the evolution of AGN host galaxies. I investigate this possible secular co-evolution of galaxies and black holes further by measuring the black hole masses of a sample of 101 bulgeless AGN host galaxies and compare them to typical black hole-galaxy scaling relations. I find that the measured black holes of the bulgeless galaxies are ~1-2 dex more massive than they should be, given their lack of bulges. This suggests that black hole-galaxy scaling relations may arise due to mutual correlations to the overall gravitational potential of the dark matter halo of the galaxy. I also considered the effect of the group environment on the time and rate that quenching occurs, with respect to the group-centric radius, for 4,629 satellite galaxies. I find that although mergers, mass quenching and morphological quenching are all occurring in groups, environmentally driven quenching mechanisms are also prevalent. However, I find that these environmentally driven quenching processes are not correlated with the velocity of a satellite within a group, ruling out ram pressure stripping as a possible mechanism. I discuss how all of these quenching mechanisms are likely to affect a galaxy across its lifetime, acting in concert to reduce the SFR, which in turn produces the wide distribution of quenching timescales seen across the colour-magnitude diagram. I discuss ideas for future work using the method employed in this work, including applying it to forthcoming data from large integral field unit surveys.

Many uncertainties remain as to how the most massive stars are formed and how they interact with their environment via radiative and mechanical processes. This feedback may affect future generations of star formation -- triggering it by compressing gas, or hindering it by dispersing reservoirs. These scenarios can be simulated by solving the equations of hydrodynamics and radiative transfer. However, the latter is usually simplified due to its computational expense, despite its importance in determining the dynamics. In this thesis, I describe how I increased the efficiency of the radiation hydrodynamics code, TORUS, which uses a Monte Carlo approach to solving the radiative transfer. Tens of millions of energy packets are propagated through a domain split over hundreds of processors running in parallel with Message Passing Interface (MPI). By re-examining and improving communication algorithms, I lowered the radiation run time by about a factor of ten, making it tractable to run three-dimensional simulations of massive star feedback in clusters. This includes both the stellar and diffuse radiation fields, with multiple atomic species and silicate dust grains. The full ionization states and temperatures can then be fed in to produce self-consistent synthetic observations. I applied this to clouds of 1000 and 10,000 solar masses with surface density 0.01 g/cm^2, containing a 34 solar mass star, with photoionization and radiation pressure feedback. Photoionization is efficient at shaping and dispersing clouds. The expanding ionization front forms dense, spherical knots with pillars pointing away from the emitting star. These resemble the Pillars of Creation in the Eagle Nebula, and the proplyds observed in the Orion Nebula. In the lower-mass model, almost all material is removed from the (15.5 pc)^3 grid within 1.6 Myr; the higher mass cloud is somewhat more resistant, with 25 per cent remaining inside (32.3 pc)^3 after 4.3 Myr. Radiation pressure has a negligible effect, but will be more important for denser clouds or higher luminosities.