College of Science and Health Theses and Dissertations

Date of Award

Summer 8-21-2016

Degree Type


Degree Name

Master of Science (MS)



First Advisor

Jesus Pando, PhD

Second Advisor

Anuj Sarma, PhD

Third Advisor

Bernhard Beck-Winchatz, PhD


We use the method of wavelet transforms to investigate the clustering of matter on galactic scales in search of Baryon Acoustic Oscillations (BAOs). In particular, we develop a method of wavelet packet analysis to measure the power spectrum of a galaxy distribution and apply this method to the CMASS galaxy catalogue from the Sloan Digital Sky Survey (SDSS) Baryon Oscillation Spectroscopic Survey (BOSS) collaboration. Using a variant of HEALPix, we project the data from the celestial sphere onto a square signal matrix, and take the two-dimensional Wavelet Packet Transform of this signal. We use this transform and techniques of spectrum estimation to estimate the power spectrum, and extract the BAO signature from this measured power spectrum. Using fitting methods, we compare our results to a fiducial ΛCDM flat cosmological model and previous results from the BOSS collaboration, and we detect a BAO signature in the power spectrum comparable to the previous consensus results of the BOSS collaboration. In reproducing these results, our method of spectrum estimation is an improvement on established methods insofar as it requires no free nuisance parameters, other secondary manipulations, or mock catalogues. In particular, we calculate two parameters that determine how well our results fit previous studies and models, where a value of 1 for a given parameter indicates a perfect fit. For the parameter α, which measures how well our data fits a fiduciary concordance ΛCDM model, we find α ≈ 0.94. For the parameter β, which measures how well our BAO matches the results from the SDSS collaboration, we find that β ≈1. In both parameters there are slight variations depending on the particular wavelet used and the resolution of the signal.

SLP Collection


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Physics Commons