Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"Sloan Digital Sky Survey (SDSS)"”.
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The Origins and Environments of Quasar Absorption Lines in the Sloan Digital Sky Survey
Owing to the advent of large spectroscopic surveys such as the Sloan Digital Sky Survey (SDSS), tens of thousands of quasar absorption line (QAL) systems have been identified to date. QAL catalogs currently extend to z ∼ 4.6 and provide unique probes of the large scale structure of baryonic …
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Missing channel reconstruction for sloan digital sky survey images using linear models and generative adversarial networks
The Sloan Digital Sky Survey (SDSS) dataset, one of the largest astronomical surveys, suffers from noise and missing information in some of the image channels. This thesis implements two methods—the linear model and the deep learning model—on 12,730 SDSS images for missing channel re- construction. …
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Classification of Stars from Redshifted Stellar Spectra utilizing Machine Learning
… of stellar spectra but few that involve the Sloan Digital Sky Survey (SDSS). Stellar spectra from the SDSS are applied to standard classification methods such as K-Nearest Neighbors, Random Forest, and Support Vector Machine to automatically classify the spectra. Stellar spectra are high …
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Quantitative analysis of 3-arm spiral galaxies
… Most of our work involved images taken from the Sloan Digital Sky Survey (SDSS), supplemented with high-resolution Hubble Space Telescope (HST) observations. This allowed us to study the morphological demographics of our sample, for both the internal structure and arm symmetry. The HST images …
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The Optical Variability of Quasars as Seen by SDSS
… confirmed quasars recently assembled by the Sloan Digital Sky Survey (SDSS). This database is an excellent data set to study quasar variability, and includes 9,000 well-sampled light curves from Stripe 82 and a 25,000-object two-epoch sample from the northern Galactic sky. I show that the …
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Lenticular galaxies - the one in the middle
… A sample of lenticular galaxies from the Spitzer Survey of Stellar Structure in Galaxies (S4G) using the Spitzer Space Telescope along with Sloan Digital Sky Survey (SDSS) was used for this project to study molecular gas properties as well morphologies associated with dust where molecular gas is …
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Constraints on early-type galaxy structure from spectroscopically selected gravitational lenses
… describes all aspects of a unique spectroscopic survey for strong galaxy-galaxy gravitational lenses: motivation, candidate selection, ground-based spectroscopic follow-up, Hubble Space Telescope imaging, data analysis, and results on the radial density profile of the lens galaxies. The lens …
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Activity and kinematics of low mass stars
… of approximately 70000 M dwarfs from the Sloan digital Sky Survey (SDSS) Data Release 7. This new analysis explores the spatial distribution of these M dwarf properties as a function of vertical distance from the Galactic plane (Z) and distance from the Galactic center (R). We confirm the …
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The complete universe: probing magnitude completeness and evolution in galaxy redshift surveys
… characterise the study of magnitude-redshift surveys for the estimation of galaxy luminosity functions (LF). Estimating LFs, either parametrically or non-parametrically, generally requires the assumption of separability between the LF, and the density function. The work carried out initially …
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Large Quasar Groups at Redshift ~ 2
… investigating Large Quasar Groups (LQGs) are the Sloan Digital Sky Survey (SDSS) and the 2dF Quasar Redshift Survey (2QZ). These have been used: to investigate stripe 82 of the SDSS; to discover large scale structures, specifically LQGs in the early universe; to investigate the expectation of …
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Star formation and environment of galaxies
… photometric and spectroscopic data from the Sloan Digital Sky survey (SDSS) we show how common observables, such as colour, SFR, and SFR/M* are influenced when galaxies are assembled into clusters via large-scale filaments. We discover that complex galaxy populations (e.g. blue passive …
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GALAXY-HALO CONNECTION AND CLUSTERING IN THE PRESENCE OF DYNAMICAL DARK ENERGY AND MASSIVE NEUTRINOS
… neutrinos, considering the datasets from the Sloan Digital Sky Survey (SDSS) for redshifts z < 0.2, and from the Cosmological Evolution Survey (COSMOS 2020) for 0.2 < z < 2. Implementing such a method, the author has populated with galaxies the dark matter structures in the DEMNUni simulations …
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Bulges and Disks in the Nearby Universe: Applications to Evolution and Formation of Galaxies
… selected galaxies drawn from the Sloan Digital Sky Survey (SDSS) Data Release 7. Fits are performed for the SDSS r-band utilizing the fitting routine Galfit and analysis pipeline PyMorph. Simulations are used to test the two-dimensional decompositions of SDSS galaxies. We compare …
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Measurements and implications of the SDSS DR7 galaxy angular power spectrum
… power spectrum of galaxies selected from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) by using a quadratic estimation method with KL-compression. The primary data sample includes over 18 million galaxies covering more than 5,700 square degrees after masking areas with bright …
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Particle physics in the sky and astrophysics underground : connecting the universe's largest and smallest scales
… laboratories. The "Particle Physics in the Sky" portion of this thesis focuses on extracting cosmological information from galaxy surveys. To overcome technical challenges faced by the latest galaxy surveys, we produced a comprehensive upgrade to mangle, a software package that processes the …
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Galaxy Formation in the Lambda-Cold Dark Matter Cosmology
… model predictions using observations from the Sloan Digital Sky Survey (SDSS). I use two different variants of the model, Baugh et al (2005), which assumes a top-heavy initial mass function (IMF) in starbursts and superwind feedback, and Bower et al (2006), which incorporates AGN feedback with …
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Identifying intervening absorption systems for use as cosmological probes
… being one of the most luminous objects in the sky can act as cosmological probes for analyzing not only the large-scale structures (LSSs) in the universe, but also to trace the metal absorption systems by probing the gas content (Zibetti et at., 2005; Ménard et at., 2005) that lie on the …
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Multi-versioned Data Storage and Iterative Processing in a Parallel Array Database Engine
… an unprecedented scale and rate. For example the Sloan Digital Sky Survey (SDSS) generates 200GB of data containing millions of objects on each night on its routine operation. The large hadron collider is producing even more data today which is approximately 30PB annually. The Large Synoptic …
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Insights into the nature of dust attenuation in relation to galaxy evolution from local to cosmic noon galaxies
… sample of local star-forming galaxies from the Sloan Digital Sky Survey (SDSS). We use machine learning and advanced statistical techniques to study which galaxy physical parameter is the most important in determining the dust attenuation. We find that the stellar mass leads over all other …
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Studying the environmental dependence of star formation properties of galaxies in the Abell 1437 galaxy cluster and its surrounding large scale structure
… a seeing matched photometric catalogue from Sloan Digital Sky Survey (SDSS) and UKIRT Deep Sky Survey (UKIDSS) imaging data. The photometric dataset is complemented by a near uniformly sampled spectroscopic dataset from the SDSS and Two Degree Field (2dF) survey. Stellar masses and star …
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