The Oosterhoff phenomenon presents a challenge to the accretion model for the buildup of at least part of the Milky Way halo. The existence of the Oosterhoff gap among the globular clusters in the halo of the Milky Way, while globular clusters in satellite galaxies tend to fall in this gap, seems to contradict the idea that the halo was formed through the accretion of objects similar to these current satellite galaxies. This dissertation seeks to better understand the Oosterhoff phenomenon through a systematic study of RR Lyrae stars in globular clusters in the Large Magellanic Cloud (LMC). Similar studies have been carried out on a set of Milky Way globular clusters which fall in the Oosterhoff-I (Oo-I) and Oosterhoff-II (Oo-II) classes but few studies with the requisite level of detail have been carried out on extragalactic objects.This dissertation set out to study the differences between RR Lyrae stars in Oo-I/II clusters and those in Oo-int clusters. Answers for three specific questions were sought. 1.) How do the properties of double-mode RR Lyrae stars in Oo-int clusters compare to those in Oo-I/II clusters? 2.) How do the positions of RR Lyrae stars on the Bailey diagram differ between stars in Oo-int clusters and those in Oo-I/II clusters. 3.) How do the physical properties of RR Lyrae stars, obtained through the Fourier decomposition of their light curves, change when going from Oo-I/II clusters to Oo-int clusters? The implications that this study has on the nature of the Oosterhoff dichotomy are also discussed.
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