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 30 for “"spectral energy distribution"”.
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Spectral Energy Distribution Modelling of X-ray Selected AGNs and Their Host Galaxies
The nature of the relation between active galactic nuclei (AGN), and their host galaxies have been observed in detail throughout the Universe. Such work has found an intrinsic link between central supermassive black hole (SMBH) masses, and host galaxy properties such as the velocity dispersion of …
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Evolution of the Stellar Mass Density of Galaxies Since Redshift 1.0
… delivers an estimation of the redshift and the spectral energy distribution. The stellar mass-to-light ratio, that is known from the library for all types of spectral energy distribution, together with the flux measurement in one of the COMBO-17 filters in the optical regime delivers an …
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Determination of the far-infrared properties of galaxies in the Coma cluster
… of 68 of these galaxies were determined from spectral energy distribution fits across the full wavelength range. Finally, these galaxies were grouped by morphological type, resulting in 30 elliptical galaxies, 37 spiral galaxies and one with an unknown morphology. These results were then …
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Extending the depth of focus using digital image filtering
… is based on the intuitive concept that the spectral energy distribution of a focused object is biased towards lower frequencies after blurring. This approach requires digital image filtering in the spatial frequency domain. A comparison among methods of both types is made using a …
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The Determination of the Thermal Neutron Flux in a Research Reactor
… of the neutron flux, and of its spatial and spectral energy distribution is of great importance, not only for purposes of experimental reactor physics (e.g., determination of specific data with regard to a new reactor), and for reactor operation (e.g., determination of reactor power level) …
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The Andromeda Optical and Infrared Disk Survey
The spectral energy distributions of galaxies inform us about a galaxy’s stellar populations and interstellar medium, revealing stories of galaxy formation and evolution. How we interpret this light depends in part on our proximity to the galaxy. For nearby galaxies, detailed star formation …
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Probing diffuse galactic synchrotron emission using meerkat single dish data
… one way to probe said emission is to measure the spectral index of this power law. From the various results available in the literature, the average spectral index for frequencies that are between 0.408 and 3.8 GHz is ∼ −2.7. In this study, the MeerKLASS UHF-data (544-1087 MHz) was used alongside …
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Studies on the gamma-ray burst phenomenon and on its use to probe the high redshift universe
… The analysis of the X-ray to-optical spectral energy distribution of 22 GRBs shows that synchrotron emission works well for most afterglows as a simple spectral model, on the other hand the dynamical model of the expansion is difficult to reconcile with the observations. A low …
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Detecting episodes of star formation using Bayesian model selection.
… of star formation from the analysis of the Spectral Energy Distribution (SED) of galaxies. This method is validated by simulating galaxy catalogs modeled after 3D-HST galaxies at redshift z ∼ 1. The SED of galaxies are derived using multivariate kernel density estimates of the input …
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Tail estimation of the spectral density under fixed-domain asymptotics
… Gaussian random field on $mathbb{R}^d$ with the spectral density $f(ulambda)$ that satisfies $f(ulambda) ~sim~ c, |ulambda|^{-theta} $ as $|ulambda| ~rightarrow~ infty$, the parameters $c$ and $theta$ control the tail behavior of the spectral density where $theta$ is related to the smoothness of …
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Properties of the population of field galaxies at medium redshift
… they were classified according to redshift and spectral energy distribution. In this work we present analysis of the population of galaxies in the redshift range of 1.1 > z > 0.1. For late type galaxies no evidence for evolution in the B--band luminosity function can be found over the whole …
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Infrared excesses from accretion streams in pre-main-sequence binaries
… ratios and eccentricities and calculated the spectral energy distribution of the binary-disk system, for an optically thick disk. We focused on the variation of the excess in the N band (effective wavelength ∼11mum). The result of the mass streams is a considerable infrared excess that …
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The evolution of star-forming galaxies : analysis of infrared observations by AKARI
… atomic emission lines detected, and star-forming spectral energy distribution templates are fitted to these sources using the multi-wavelength data available. The majority of these galaxies are dominated by emission from star formation, and local sources show relatively low dust extinction. …
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Introducing the Texas Euclid Survey for Lyman Alpha (TESLA) survey : initial study correlating galaxy properties to Lyman-alpha emission
… on the Hobby-Eberly Telescope. We perform spectral energy distribution (SED) fitting to compute the galaxy properties of 43 LAEs, and study correlations between stellar mass, star formation rate (SFR), and dust, to the Lyα rest-frame equivalent width (W [subscript Lyα]). We uncover marginal …
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Probing Galaxy Evolution with AKARI
… models. These models are dependent on both the Spectral Energy Distribution (SED) templates and evolution of the galaxy types. The phenomenological backwards evolution model of Pearson 2005 appeared to be consistent with the number counts. To probe this, number counts were extracted from below …
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Early Stages of Massive Star Formation at High Spatial Resolution
… kinematics of UCHII regions at high spatial and spectral resolution. NIR-polarimetric maps of the reflection nebula that are generally found around these objects are used to rule out the presence of deeply embedded companions of a Young Stellar Object (S106) and to identify multiplicity in the …
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Observational Properties of Gigaelectronvolt-Teraelectronvolt Blazars and the Study of the Teraelectronvolt Blazar RBS 0413 with VERITAS
… jet is currently an essential question in high-energy astrophysics. A blazar spectral energy distribution (SED) has a typical double-peaked shape in the flux vs. energy representation. The low-energy component of the SED is well-studied and thought to be due to synchrotron emission from …
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Radio Observations of Discs around Young Stellar Objects
… dust in the disc of DG Tau B by looking at its spectral energy distribution (SED). We also analyse the proper motions of DG Tau B and the classical T Tauri star DG Tau A to determine if they are a binary. We fit a modified blackbody to the DG Tau B SED and model the dust using a temperature of …
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The influence of planetary and stellar companions on debris discs
… of these discs can be constrained through spectral energy distribution (SED) modelling or direct imaging of the dust. Gravitational perturbations in a system containing planets or multiple stars can influence the evolution of a disc and leave observable signatures in the disc’s structure, …
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Time-Domain Astrophysics with the Transiting Exoplanet Survey Satellite
… often observed contemporaneously with the high-energy emission from these bursts. Chapter 7, in particular, aims to connect the prompt optical flash to the high-energy spectral energy distribution (SED), and explains the suppression of the optical flash (compared to the extrapolation of the …
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