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Relevant bibliographies by topics / Observational astronomy / Dissertations / Theses

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Dissertations / Theses on the topic 'Observational astronomy'

Author: Grafiati

Published: 4 June 2021

Last updated: 27 April 2022

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1

Widicus, Weaver Susanna Leigh Beauchamp Jesse L. "Rotational spectroscopy and observational astronomy of prebiotic molecules /." Diss., Pasadena, Calif. : California Institute of Technology, 2005. http://resolver.caltech.edu/CaltechETD:etd-05162005-153745.

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2

Corrigan, Ruth T. "Observational manifestations of gravitational lenses." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260611.

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3

Añez, López José Ignacio. "Observational and theoretical perspective of massive star formation." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/671784.

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In this thesis, we are aimed to better understand the massive star formation process paying special attention to the role of the magnetic field. To do this, we will carry out a multi-scale analysis with a double approach, theoretical and observational. a) The role of the magnetic field in the fragmentation process: the case of G14.225-0.506 In this first work, we study the fragmentation of an infrared dark cloud that has a filamentary structure and two hubs. We will pay special attention to the magnetic field present in the environment of the hubs and we will try to relate it to the di

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4

Kelly, Brandon Charles. "Observational Constraints on the Structure and Evolution of Quasars." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193633.

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I use X-ray and optical data to investigate the structure of quasars, and its dependence on luminosity, redshift, black hole mass, and Eddington ratio. In order to facilitate my work, I develop new statistical methods of accounting for measurement error, non-detections, and survey selection functions. The main results of this thesis follow. (1) The statistical uncertainty in the broad line mass estimates can lead to significant artificial broadening of the observed distribution of black hole mass. (2) The z = 0.2 broad line quasar black hole mass function falls off approximately as a power law

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5

Uthas, Helena. "Observational studies of highly evolved cataclysmic variables." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/202889/.

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Cataclysmic Variables (CV) are binary systems where a main-sequence star transfers mass onto a white dwarf (WD). According to standard evolutionary theory, angular momentum loss drives CVs to initially evolve from longer to shorter orbital periods until a minimum period is reached (≈ 80 minutes). At roughly this stage, the donors becomes degenerate, expand in size, and the systems move towards longer orbital periods. Theory predicts that 70% of all CVs should have passed their minimum period and have sub-stellar donors, but until recently, no such systems were known. I present one CV showing e

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6

Seigar, Marcus S. "Observational studies of the structure of spiral galaxies." Thesis, Liverpool John Moores University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242314.

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7

Nelson, Andrew Frederick. "Dynamics and observational appearance of circumstellar disks." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/288969.

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In my thesis I present a study of the dynamics and observational characteristics of massive circumstellar disks in two dimensions (r, φ) using two complimentary hydro-dynamic codes: a 'Smoothed Particle Hydrodynamic' (SPH) code and a 'Piecewise Parabolic Method' (PPM) code. I also study the detection limits available to radial velocity searches for low mass companions to main sequence stars. This thesis is organized as a series of published or submitted papers, connected by introductory and concluding material. I strongly recommend that readers of this abstract obtain the published versions of

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8

Stempels, Henricus Cornelis. "An Observational Study of Accretion Processes in T Tauri Stars." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3420.

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9

Endicott, Thomas G. "Effect of Observational Cadence on Orbit Determination for Synthetic Near-Earth Objects." Thesis, University of Massachusetts Boston, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10617372.

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<p> Near-Earth Objects (NEOs) are generally small, dark, and fast-moving. Multiple observations over time are necessary to constrain NEO orbits. Orbits based on observational data are inherently uncertain. Here we describe code written in Python and Fortran used to generate synthetic asteroids and compare calculated orbital fit based on noisy ephemeris using the a distance criteria, D-value. Observational sessions separated by more than one month produce very good orbital fits (low D-values) even at the highest noise level. Daily observational sessions show the highest D-values, as expected, s

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10

Moffat, Anthony F. J. "Observational overview of clumping in hot stellar winds." Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1763/.

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In the old days (pre ∼1990) hot stellar winds were assumed to be smooth, which made life fairly easy and bothered no one. Then after suspicious behaviour had been revealed, e.g. stochastic temporal variability in broadband polarimetry of single hot stars, it took the emerging CCD technology developed in the preceding decades (∼1970-80’s) to reveal that these winds were far from smooth. It was mainly high-S/N, time-dependent spectroscopy of strong optical recombination emission lines in WR, and also a few OB and other stars with strong hot winds, that indicated all hot stellar winds likely to b

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11

Leverington, David. "The cost and citation-based effectiveness of observational astronomical facilities since 1958." Thesis, Open University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363964.

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12

Shidatsu, Megumi. "Observational Studies of Accretion Disks in Black Hole X-ray Binaries." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199106.

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13

Ng, Shao-Chin Cindy. "Cosmological models with quintessence : dynamical properties and observational constraints." Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phn5758.pdf.

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Bibliography: leaves 100-106. Studies different models of "quintessence", in particular, a quintessence arising from an ultra-light pseudo Nambu-Goldstone boson. Overviews dynamical properties for these models using phase-space analyses to study attractor and tracker solutions. Studies high-redshift type Ia supernovae constraints on these models. Studies the impact of a simple phenomenological model for supernovae luminosity evolution on the PNGB models and the potentials of a future supernovae data set to discriminate the PNGB models over the other quintessence models. Studies gravitational l

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14

Harding, Paul. "The formation of the Galactic bulge and halo: Observational signatures." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/289743.

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The evolution of tidal debris within the Galactic halo has been simulated to determine its detectability within the constraints imposed by currently available telescopes and instrumentation. Observations of the simulations show that there is a very high probability of detecting and quantifying the presence of tidal debris with a pencil beam survey of 100 square degrees. The debris is readily detectable via the presence of kinematic substructure in the radial velocities. The detection probabilities show surprisingly little change with the age of the debris. Accretion events that occurred up to

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15

Charnock, Tom. "Early universe cosmology and its observational effects on the cosmic microwave background." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/42164/.

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This Thesis is written in three parts. The first part describes the analytic calculation of the unequal-time correlator of cosmic strings and superstrings. The first efficient constraint analysis of all string and superstring network parameters is performed. By studying the effect of cosmic strings on the cosmic microwave background (CMB) radiation it is discovered that cosmic strings must make up a vanishingly small proportion of the energy density of the universe. The constraints on string network parameters are all skewed toward reducing the magnitude of energy density arising from strings.

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16

Savage, Chandra Shannon. "Ions, isotopes, and metal cyanides: Observational and laboratory studies." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/290082.

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Chemistry in the interstellar medium is very different from the processes which take place in terrestrial settings. Environments such as circumstellar envelopes, molecular clouds, and comets contain diverse and complex chemical networks. The low temperatures (10-50 K) and densities (1-10⁶ cm⁻³) allow normally unstable molecules to exist in significant quantities. At these temperatures, the rotational energy levels of molecules are populated, and thus these species can be detected by millimeter-wave radio astronomy. The detection and quantification of interstellar molecules, including metal cya

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17

Davidson, James W. Jr. "A New Era of Observational Capability at Ritter Observatory: Spectropolarimetry from Exoplanets to Circumstellar Disks and Beyond." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1365171803.

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18

Trilling, David Eric. "A theoretical and observational study of the formation and evolution of planetary systems and extrasolar planets." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/288998.

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The recent discoveries of extrasolar giant planets (planets like Jupiter orbiting other stars like our Sun) at small distances from their central stars have revitalized the fields of planet and planetary system formation. The discoveries have overturned the former paradigm for planetary system formation which suggested that all planetary systems would look like our Solar System: these decidedly do not. The new view is that the early solar system was not nearly the quiescent place previously thought, but rather a dynamic environment in which planets are both easily created and easily destroyed.

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19

Friedman, Andrew. "Infrared Light Curves of Type Ia Supernovae." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10116.

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This thesis presents the CfAIR2 data set, which includes over 4000 near-Infrared (NIR) \(JHK_s\)-band measurements of 104 Type Ia Supernovae (SN Ia) observed from 2005-2011 using PAIRITEL, the 1.3-m Peters Automated InfraRed Imaging TELescope at the Fred Lawrence Whipple Observatory (FLWO) on Mount Hopkins, Arizona. While the discovery of dark energy and most subsequent supernova cosmology has been performed using optical and Ultraviolet wavelength observations of SN Ia, a growing body of evidence suggests that NIR SN Ia observations will be crucial for future cosmological studies. Whereas SN

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20

Kilpatrick, Charles Donald, and Charles Donald Kilpatrick. "New Observational Insight on Shock Interactions Toward Supernovae and Supernova Remnants." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621574.

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Supernovae (SNe) are energetic explosions that signal the end of a star's life. These events and the supernova remnants (SNRs) they leave behind play a central role in stellar feedback by adding energy and momentum and metals to the interstellar medium (ISM). Emission associated with these feedback processes, especially atomic and molecular line emission as well as thermal and nonthermal continuum emission is known to be enhanced in regions of high density, such as dense circumstellar matter (CSM) around SNe and molecular clouds (MCs). In this thesis, I begin with a brief overview of the physi

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21

Williams, Rik Jackson. "The warm-hot environment of the Milky Way." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1154972702.

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22

Sjöbom, Ludvig. "The ultraviolet spectral slope of high-redshift galaxies." Thesis, Uppsala universitet, Observationell astrofysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-310603.

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The slope of the ultraviolet continuum emissions from a galaxy between 1250 and 2600 Å provides insights about several facets of the galaxy. Mainly, it is well-correlated with the amount of dust. This work presents a search for objects whose UV-continuum slopes are excessively steep, as well as suggestions for follow-up. The method used is looking through existing data sets, and proposing follow-up of the outliers in the distribution of slopes. Close to fifteen objects with slopes beyond what is easily explained by theory are presented. Since these lie beyond the realm of current theories, con

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23

Zack, Lindsay Nicole. "Laboratory and Observational Studies of Transient Molecules at Microwave and Millimeter/Submillimeter Wavelengths." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/217089.

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In this dissertation, techniques of high-resolution rotational spectroscopy have been used to measure the spectra of molecules in both laboratory and astronomical settings. In the laboratory, small metal-bearing molecules containing zinc, iron, nickel, titanium, yttrium, and scandium have been studied at microwave and millimeter/submillimeter wavelengths in order to determine their rotational, fine, and hyperfine constants. These molecules were synthesized in situ in direct-absorption and Fourier-transform microwave spectrometers using Broida-type ovens and laser ablation methods. From the spe

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24

Namekata, Kousuke. "Observational Studies of Extreme Stellar Magnetic Activities: Spots, Flares, and Mass Ejections." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263473.

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25

Johnson, Elsa M. 1971. "Host stellar population properties and the observational selection function of type Ia supernovae." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/11297.

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xlix, 348 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.<br>Supernovae Ia are viable standard candles for measuring cosmological distances because of their enormous light output and similar intrinsic brightness. However, dispersion in intrinsic brightness casts doubt on the overall reliability of supernovae as cosmological distance indicators. Moreover, as shown in this thesis, the dependence of peak brightness on host galaxy properties significantly contributes to this dispersion. As a resu

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26

Kelvin, Lee Steven. "The structure of galaxies : the division of stellar mass by morphological type and structural component." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3689.

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The mechanisms which cause galaxies to form and evolve each leave behind distinct structural markers in their wake. Dynamically hot processes (e.g., monolithic collapse, hierarchical merging) give rise to pressure-supported spheroidal structures, including elliptical galaxies and classical bulges. By contrast, dynamically cold processes (e.g., gas accretion, AGN splashback) lead to flattened rotationally-supported disk-like structures, often found on their own or as part of a spiral galaxy. If left in isolation for a sufficient length of time, secular evolutionary processes cause the formation

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27

Zach, Juergen Johann. "Observational Signatures of the Macroscopic Formation of Strange Matter during Core Collapse Supernovae." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1053470113.

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28

Hamacher, Duane Willis Physics Faculty of Science UNSW. "A search for transiting extrasolar planets from the southern hemisphere." Publisher:University of New South Wales. Physics, 2008. http://handle.unsw.edu.au/1959.4/40943.

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To date, more than 300 planets orbiting stars other than our sun have been discovered using a range of observing techniques, with new discoveries occuring monthly. The work in this thesis focused on the detection of exoplanets using the transit method. Planets orbiting close to their host stars have a roughly 10 per cent chance of eclipsing (transiting) the star, with Jupiter?sized planets causing a one per cent dip in the flux of the star over a few hours. A wealth of orbital and physical information on the system can be extracted from these systems, including the planet density which is esse

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29

Donevski, Darko. "Identification et modélisation des galaxies distantes dans les relevés cosmologiques du satellite Herschel." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0323/document.

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La population de galaxies poussiéreuses ayant un fort taux de formation stellaire (Dusty Star Forming Galaxies, DSFGs) joue un rôle très important dans l’histoire de l’univers, avec des taux de formation d’étoiles allant de quelques centaines à quelques milliers de masses solaires par an. Les sondages infrarouges, comme ceux entrepris à l’aide du satellite Herschel, nous offrent l’opportunité de recenser de manière approfondie ces DSFGs jusqu’à de grands décalages spectraux. Cependant, jusqu’à présent seul un petit nombre de DSFG détecté par Herschel ont été confirmés pour être à des décalages

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30

Johnston, Katharine G. "Observational signatures of massive star formation : an investigation of the environments in which they form, and the applicability of the paradigm of low-mass star formation." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1895.

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This thesis presents both a study of the cluster-scale environments in which massive stars form, investigating in particular how the ionized gas in these regions relates to the molecular star-forming material, as well as detailed studies of two luminous forming stars, AFGL 2591 and IRAS 20126+4104, to determine whether they are forming similarly to their low-mass counterparts. The results of this work include the identification of 35 HII regions (20 newly discovered) via a radio continuum survey of ionized gas towards 31 molecular cluster-forming clumps. The observed ionized gas was found to b

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Abbas, Mohamad. "A search for Long-Period Variable Stars in the Globular Cluster NGC 6496." Bowling Green State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1308597257.

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32

Kager, Elisabeth. "Pulsation Properties of Long Period Variable Stars in Globular Cluster NGC 6553." Bowling Green State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1277148078.

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33

Suchyta, Eric Daniel. "Embrace the Dark Side: Advancing the Dark Energy Survey." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440098241.

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34

Court, A. J. "Hard X-ray astronomy from balloon altitudes." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377796.

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35

Zadrozny, Andrew. "Spectroscopic techniques and observations in infrared astronomy." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46625.

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36

Garcia, Garcia Carlos. "Theories of gravitation confronted with cosmological observations." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/670878.

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This thesis studies Dark Energy, a central topic of Modern Cosmology, from different points of view. It covers from models and parametrizations to likelihood approximations for the observations of the Large Scale Structure (LSS) of the Universe, which are vital for model constraining, as well as for our study of the S8 tension. The studied model is the α-attractors dark energy model, which reproduces current observations thanks to its capability to mimic a cosmological constant. It is inspired on the Planck-favored inflationary class of models α-attractors and links the inflationary and dar

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37

Alp, Dennis. "Core-collapse Supernovae : Theory vs. Observations." Licentiate thesis, KTH, Partikel- och astropartikelfysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-241431.

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A core-collapse supernova (CCSN) is an astronomical explosion that indicates the death of a massive star. The iron core of the star collapses into either a neutron star or a black hole while the rest of the material is expelled at high velocities. Supernovae (SNe) are important for the chemical evolution of the Universe because a large fraction of the heavier elements such as oxygen, silicon, and iron are liberated by CCSN explosions. Another important role of SNe is that the ejected material seed the next generation of stars and planets. From observations, it is clear that a large fraction of

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38

Zbinden, Jonas. "Planning Observations of Terrestrial ExoplanetsAround M Type Stars with CRIRES+." Thesis, Uppsala universitet, Observationell astrofysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-437673.

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In recent decades, thousands of exoplanets have been discovered. The next step is to characterize theobserved planets in terms of their radii, masses, density, physical conditions and composition of theiratmospheres. Several space-based observatories such as TESS and CHEOPS have started determiningthe first three observables but characterization of exoplanetary atmospheres is waiting for observationcampaigns with instruments like CRIRES+ at the VLT and NIRSpec on the JWST. To ensure the efficiencyof data acquisition, careful planning of observations is necessary. In this project we developeda

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39

Myers, Richard Michael. "High spectral resolution gamma ray astronomy in the energy region 50keV to l0MeV." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6413/.

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Observations of the Crab nebula region and of the unusual active galaxy NGC1275 made during a balloon flight of the Durham high spectral resolution gamma ray telescope are described. From the Crab, spectral line fluxes were detected at 79 keV (transient), 405 keV, and at 1050 keV. The first two are possible confirmation of previous results. From NGC1275, evidence of two-photon electron-positron annihilation radiation with the expected redshifted energy of 502 keV was observed. Possible interpretations are suggested.

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Warell, Johan. "Regolith Properties of Mercury Derived from Observations and Modelling." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://publications.uu.se/theses/91-554-5535-2/.

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41

Hill, David T. "The optical and NIR luminous energy output of the Universe : the creation and utilisation of a 9 waveband consistent sample of galaxies using UKIDSS and SDSS observations with the GAMA and MGC spectroscopic datasets." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1696.

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Theories of how galaxies form and evolve depend greatly on constraints provided by observations. However, when those observations come from different datasets, systematic offsets may occur. This causes difficulties measuring variations in parameters between filters. In this thesis I present the variation in total luminosity density with wavelength in the nearby Universe (z<0.1), produced from a consistent reanalysis of NIR and optical observations, taken from the MGC, UKIDSS and SDSS surveys. I derive luminosity distributions, best-fitting Schechter function parameterisations and total luminos

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Turner, James Edmund Henry. "Astronomy with integral field spectroscopy : observation, data analysis and results." Thesis, Durham University, 2001. http://etheses.dur.ac.uk/3765/.

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With a new generation of facility instruments being commissioned for 8 metre telescopes, integral field spectroscopy will soon be a standard tool in astronomy, opening a range of exciting new research opportunities. It is clear, however, that reducing and analyzing integral field data is a complex problem, which will need considerable attention before the full potential of the hardware can be realized. The purpose of this thesis is therefore to explore some of the scientific capabilities of integral field spectroscopy, developing the techniques needed to produce astrophysical results from the

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Tan, Boon Kok. "Development of coherent detector technologies for sub-millimetre wave astronomy observations." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:398fda64-e486-4917-b2e4-8e1dfe5d5c83.

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Superconductor-Insulator-Superconductor (SIS) mixers are now used regularly in sub- millimetre astronomical receivers. They have already achieved sensitivity approaching the quantum limit at frequencies below the superconducting gap of niobium (~680 GHz). Above that, the mixer performance is compromised by losses, unless materials with higher superconducting gap are employed in conjunction with the niobium tunnel junction. In this thesis, we present the development of 700 GHz niobium SIS mixers, employing a unilateral finline taper on a thin Silicon-On-Insulator (SOI) substrate. These mixers a

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Paley, Elizabeth Sara 1967. "An infrared and optical study of bright IRAS point sources of minimum apparent temperature." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277118.

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A sample of 170 sources from the IRAS Point Source Catalog (PSC) having<br>b<br>≥ 40°, 100μm flux F₄ ≥ 2.5 Jy, and upper limit fluxes at 12, 25 and 60μm was studied on POSS and ESO photographic plates. 151 of these sources are identified as 'infrared cirrus,' thirteen as galaxies, and one as a planetary nebula; four sources lie in the Small Magellanic Cloud (SMC), and the remaining source is Saturn. Accurate infrared fluxes were obtained for 29 cirrus sources, the galaxies, and the planetary nebula. The colors of the cirrus sources support the hypothesis that the radiation is coming from a mix

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de, la Cruz Rodríguez Jaime. "Measuring the solar atmosphere." Doctoral thesis, Stockholms universitet, Institutionen för astronomi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-43646.

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The new CRISP filter at the Swedish 1-m Solar Telescope provides opportunities for observing the solar atmosphere with unprecedented spatial resolution and cadence. In order to benefit from the high quality of observational data from this instrument, we have developed methods for calibrating and restoring polarized Stokes images, obtained at optical and near infrared wavelengths, taking into account field-of-view variations of the filter properties. In order to facilitate velocity measurements, a time series from a 3D hydrodynamical granulation simulation is used to compute quiet Sun spectral

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Devogèle, Maxime. "Propriétés des astéroïdes de type L : un lien avec le Système Solaire primordial ?" Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4069/document.

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En 2006, Il a été observé que l'astéroïde (234)~Barbara possède une valeur anormalement élevée d’angle d’inversion polarimétrie. Par la suite, d'autres astéroïdes possédant la même caractéristique que Barbara ont été découverts et nommés ``Barbarians'' en référence à (234) Barbara. L'étude de ces astéroïdes constitue le sujet principal de cette thèse ayant pour but de mieux comprendre la raison de cet angle d'inversion plus élevé que la normale. La première hypothèse formulée afin d’expliquer cette anomalie polarimétrique suppose que les astéroïdes Barbarians possèdent une forme fortement irré

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Moldón, Vara Francisco Javier. "Structure and nature of gamma-ray binaries by means of VLBI observations." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/96996.

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Gamma-ray binaries are extreme systems that produce non-thermal emission from radio to very-high-energy (above TeV) gamma rays, with the energy output in the spectral energy distribution (SED) dominated by the MeV–GeV photons. Their broadband emission is usually modulated by the orbital cycle of the system, which suggests that the physical conditions are also periodic and reproducible. The diversity of systems, together with the reproducibility of the conditions within each system, makes gamma-ray binaries excellent physical laboratories in which high energy particle acceleration, diffusion, a

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Hewitt, Danté Michael. "MeerKAT observations of novalike cataclysmic variables." Master's thesis, Faculty of Science, 2020. http://hdl.handle.net/11427/32726.

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I have conducted a systematic survey of eleven nearby novalike cataclysmic variables in the radio band, using the MeerKAT radio interferometer. Radio emission is detected from four out of the eleven systems: IM Eri, RW Sex, V3885 Sgr and V603 Aql. While RW Sex, V3885 Sgr and V603 Aql had been previously detected, this is the first reported radio detection of IM Eri. These observations have doubled the sample of non-magnetic cataclysmic varaibles with sensitive radio data. I observe that at these radio detection limits, a specific optical luminosity & 2.2 × 1018 erg s−1 Hz−1 (corresponding

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49

Stevens, Jason Anthony. "Multifrequency observations of blazars." Thesis, University of Central Lancashire, 1995. http://clok.uclan.ac.uk/20140/.

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Blazars are a class of active galactic nuclei (AGN). Active galaxies are those that host compact sources of non-thermal radiation in their nuclear regions and are usually classified as being radio-loud or radio-quiet. The nature of the central source is ullcertain, but arguments based on energy budget suggest that accretion onto a supermassive black hole is the most probable scenario (Rees 1984). At present, there is no satisfactory theory that can explain the difference between radio-loud and radio-quiet AGN. The emission from radio-quiet AGN is regarded as being thermal in origin. Thermal re

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Baubock, Michael, and Michael Baubock. "Effects of Spin on Neutron-Star Observations." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621065.

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Measurements of neutron-star properties provide a natural way to test models of cold dense matter and theories of gravity. In order to correctly interpret these measurements, accurate models taking into account the special and general relativistic effects arising from the strong gravity and fast spin of these sources are necessary. Moreover, for some observables the effects of the rapid spin can dominate the measurement. In this thesis, I develop a ray-tracing algorithm using the Hartle-Thorne metric that allows me to determine the effects of gravity on several observables. I use this algorith

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