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Physical Sciences and Mathematics Commons™
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Articles 1 - 5 of 5
Full-Text Articles in Physical Sciences and Mathematics
Wavelet Packet Power Spectrum Of The Sdss Lyman-Alpha Forest: A Tool For Large-Scale Structure Detection, Jason Pero
Wavelet Packet Power Spectrum Of The Sdss Lyman-Alpha Forest: A Tool For Large-Scale Structure Detection, Jason Pero
College of Science and Health Theses and Dissertations
One of the goals of astrophysics is to obtain a full understanding how the Universe is organized on large scales and how structure evolved. In this thesis we develop a method of detecting structure on Mpc scales by measuring the one-dimensional power spectrum of the transmitted ux in the Lyman- forest. The method is based on the wavelet packet transform (WPT), which has several advantages over the Fourier transform. This includes reduced noise, resulting in less data manipulation and scrubbing in the early stages of analysis. Another advantage is localization of outliers in the data, which allows the general trend …
Hierarchical Structure Formation In The Sdss Eboss Ly-Alpha Forests, Devin Becker
Hierarchical Structure Formation In The Sdss Eboss Ly-Alpha Forests, Devin Becker
DePaul Discoveries
In this study, we examine hierarchical structure at large redshifts utilizing Sloan Digital Sky Survey (SDSS) Lyman-alpha forest data. Lyman-alpha forests are absorption lines in the spectrum of quasars that serve as tracers for clouds of primordial hydrogen. These data serve as a 1-dimensional probe of the matter density field at high redshift. Using a measure sensitive to hierarchical structure formation assembled around a discrete wavelet transform, we were able to detect hierarchical structure formation in the spectrum of every quasar studied. The nature of the hierarchy seems to pertain to two forms: one that is constant across all scales, …
Better Together
DePaul Magazine
Faculty have taken full advantage of the university's innovative intercollegiate grant program, and the resulting research is as interesting and diverse as the collaborators themselves. What is resulting is research on "Patient and Primary Care Provider Perspectives on Recreational and Therapeutic Cannabis Use Within a Changing Socioculltural and Political Context;" a new minor in climate change science and policy; a new class, Communication, Coding and Entrepreneurship; brain inflammation research; and the project "Cosmology Meets Continental Philosophy: Natural Laws and Why There Is Something Rather Than Nothing"
Detection Of Baryonic Acoustic Oscillations In The Matter Power Spectrum, Spencer Everett, Ian Johnson, Jon Murphy, Mary Tarpley
Detection Of Baryonic Acoustic Oscillations In The Matter Power Spectrum, Spencer Everett, Ian Johnson, Jon Murphy, Mary Tarpley
DePaul Discoveries
Using the spectra of 22,923 high-redshift quasars from the Baryon Oscillation Spectrosocpic Survey (BOSS) subset of the Sloan Digital Sky Survey (SDSS), the authors detect evidence of the primordial baryonic acoustic oscillations (BAOs) in the matter power spectrum. The detection further endorses the currently accepted Lambda-CDM model of cosmology based upon the existence of dark energy (Lambda) and cold dark matter (CDM). Additionally, the use of the continuous wavelet transform to calculate the power spectrum has many advantages over traditional Fourier methods and independently corroborates previous detections.
Cosmic Sound In The Lyman Alpha Forest, Spencer Everett, Matt Kwiecien, Cordell Newmiller
Cosmic Sound In The Lyman Alpha Forest, Spencer Everett, Matt Kwiecien, Cordell Newmiller
DePaul Discoveries
Using the Baryon Oscillation Spectroscopic Survey (BOSS) from the Sloan Digital Sky Survey (SDSS), the authors attempt to detect the baryonic acoustic oscillations (BAOs) using the discrete wavelet transform. The wavelet transform is used to construct the power spectrum of intergalactic clouds of matter at large (Mpc) distance scales. It was found that the wavelet transform used here does not have high enough resolution to detect the BAOs. However, the techniques used in this study allow for future improvements in the transform that could potentially resolve the expected peak in the power spectrum and indicate the existence of BAOs.