Optical and X-ray studies of Be/X-ray binaries in the Small Magellanic Cloud

High-mass X-ray binaries (HMXBs) have proved to be some of the most interesting X-ray sources in the sky. The growing opulation of Small Magellanic Cloud (SMC) Be/X-ray binaries is monitored weekly with two 15ks RXTE observations. My thesis focuses on presenting the analysis of the X-ray data and the optical follow-up that enhances it. I present detailed studies of the H emission features in several prominent Be/X-ray binaries in the SMC and examine their outbursting nature by combining the OGLE optical light curves with the RXTE light curves. This has culminated in an orbital solution for SXP18.3 as well as measured orbital periods for SXP2.37, SXP172 and SXP202B. Through detections of quasi-periodic variations in the optical light curves, the details of interactions taking place between the Be star’s circumstellar disk and the neutron star are being revealed. These data are providing the building blocks that may help explain the physical processes that produce the circumstellar disk. In addition, the optical counterpart to SXP15.3 is discussed in the light of recent XMM-Newton results, raising doubt over the true optical counterpart