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 27 for “"galaxy surveys"”.
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Constraining dark energy using real and mock galaxy surveys
… measurements of large-scale clustering in future galaxy surveys, and through the imprint of a time-varying large-scale potential on the CMB (the integrated Sachs-Wolfe effect). We use semi-analytical galaxy formation models implemented in N-body simulations to build mock galaxy catalogues which …
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Tracing the Cosmos: Probing Cosmology with the Large Scale Structure of the Universe
… to isolate the information from this feature in galaxy surveys, demonstrate its robustness, and present an application to current data as well as forecasts for the next generation of cosmological surveys. Another widely discussed tension is between the amplitude of matter density fluctuations …
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Particle physics in the sky and astrophysics underground : connecting the universe's largest and smallest scales
… 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 angular masks defining the survey area on the sky. We added dramatically faster …
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Cosmological constraints using 2- and 3-point correlations with meerkat, the ska and other surveys
… intensity mapping experiments. Upcoming surveys by SKAO and HIRAX will undertake intensive line-intensity observations, complementing galaxy surveys. This study provides new forecasts on cosmological constraints derived from the combined analysis of the 21cm power spectrum and bispectrum. …
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Detecting the turnover of the power spectrum with SKAO and other surveys
… of the power spectrum with SKAO and other surveys. This thesis explores the potential of next-generation experiments, specifically the Square Kilometre Array and the Dark Energy Spectroscopic Instrument, to detect and constrain the power spectrum turnover, a key feature of the universe’s …
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Detecting the turnover of the power spectrum with SKAO and other surveys
… scales. Employing intensity mapping and galaxy surveys, we utilize Fisher forecasts and Markov Chain Monte Carlo simulations to model and analyze this subtle cosmological signature. Our findings reveal that SKA-MID Band 1 demonstrates the highest detection significance and Figure of …
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Reconstructing the Sky with CMB Lensing methods
Current and future high significance CMB lensing-galaxy cross-correlations will soon precisely probe the growth of structure and provide powerful tests for parameter tensions, non-Gaussianity, neutrino mass, and modifications to Λ−CDM and gravity. However, such cross-correlations are sensitive to …
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21 cm cosmology with optimized instrumentation and algorithms
… data from the Cosmic Microwave Background (CMB), galaxy surveys and other cosmological probes. However, most of our universe's volume, corresponding to the period between the CMB and when the first stars formed, remains unexplored. Since there were no luminous objects during that period, it is …
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The Nature of Emission-Line Galaxies in Hierarchical Cosmologies
We use a galaxy formation model to study the nature and evolution of emission line galaxies. In particular, we focus on the properties of Ly-alpha and H-alpha emitters, due to their many cosmological applications being considered for current and future observational studies. By combining a …
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Studying the Large Scale Structure and interstellar Medium of Galaxies During the Epochs of Peak Cosmic Star formation and Reionization With Infrared Fine Structure Lines
… The technique provides 3-D measurements of galaxy clustering and moments of the galaxy luminosity function. Furthermore, the linear portion of the power spectrum can be used to measure the total line emission intensity including all sources through cosmic time with redshift information …
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Regulating and Quenching Star Formation in Galaxies across the Cosmic Epochs
… identify an extremely rapidly “(mini-)quenched” galaxy at redshift z=7.3, when the universe was only 700 million years old. Its star-formation history (SFH) consists of a short and intense burst terminating only 10-40 million years before the epoch of observation. Its stellar mass is very low, …
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Early Seeds and Cosmic Skies: Quantum Origins of the Universe and Insights from Large-Scale Structure
… analyses, and advance our understanding of galaxy formation and the nature of dark energy. In Part II, we establish a technique to better understand cosmological correlators, the primary observable in the inflationary universe. Traditionally, cosmological correlators are computed with the …
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Advancing the Matter Bispectrum Estimation in Large-Scale Structure
… infancy. Additionally, information from future galaxy surveys such as LSST and Euclid will soon exceed that available from the CMB, demonstrating a pressing need for such tools. The theoretical modelling of non-linear gravitational interactions is difficult beyond the perturbative regime, …
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Topics in relativistic cosmology: Cosmology on the past lightcone and in modified gravitation
… We use the perturbed lightcone gauge in galaxy surveys and galaxy number density contrast. The significance of the new gauge is that by considering the null-like light propagations, the calculations are much simpler since angular deviations are not considered. Standard cosmology based on …
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Connecting simulations and observations in galaxy formation studies
… in order to obtain a consistent picture of galaxy formation and evolution. On the other hand, hydrodynamical simulations of galaxy formation in cosmological context are able to follow the evolution of a galaxy along cosmic time, taking into account both external processes such as mergers, …
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The inhomogeneous Universe : its average expansion and cosmic variance
… We find that the morphology of the luminous red galaxy data is marginally consistent with the one derived from simulations within the LCDM framework. In addition we illustrate, how the Minkowski functionals provide a description of clustering properties, and why this description goes beyond the …
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Design and Analysis for the DarkSide-10 Two-Phase Argon Time Projection Chamber
… for invisible "dark" matter has been found from galaxy clusters, cosmic and stellar gas motion, gravitational lensing studies, cosmic microwave background analysis, and large scale galaxy surveys. Although all studies indicate that there is a dominant presence of non-luminous matter in the …
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Projected Angular Statistics for Large-scale Structure Cosmology
… gravity and primordial non- Gaussianity. Galaxy surveys measure (sometimes approximate) redshifts and angular positions of galaxies, which trace the LSS. The natural observables are maps of the galaxy overdensity, projected in redshift bins. Similarly, line-intensity mapping (LIM) surveys …
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Probabilistic photometric redshifts in the era of petascale astronomy
With the growth of large photometric surveys, accurately estimating photometric redshifts, preferably as a probability density function (PDF), and fully understanding the implicit systematic uncertainties in this process has become increasingly important. These surveys are expected to obtain images …
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Cosmological signatures of fundamental physics
… models can be constrained in future cosmological surveys using their effect on various observables in these surveys, such as the clustering of galaxies, galaxy-galaxy lensing, and cosmic shear. Cosmological observables can also be used to constrain the properties of Dark Matter itself. While Dark …
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