Doctor of Philosophy (PhD)


Department of Physics & Astronomy

Document Type



The Galactic Bulge Survey (GBS) is a broad and shallow X-ray survey designed to detect quiescent X-ray binary systems in the direction of the Milky Way bulge, which include objects such as low-mass X-ray binaries, cataclysmic variables, and symbiotic binaries. LMXBs can provide constraints to the neutron star equation of state and symbiotic systems and are likely progenitors of double white dwarf systems which are themselves candidate progenitors to type Ia supernova. We seek to improve identification and classification of optical counterparts to GBS in several ways. By improving upon the original GBS, an updated catalog was created to help pinpoint candidate systems of these kinds by better localizing targets. With an improved catalog, we analyzed two symbiotic systems with CXB3 being classified as a possible symbiotic X-ray binary (SyXB) which could host a neutron star. We then observed other candidate symbiotics which had optical spectra taken to look for key emission seen in typical symbiotic systems. Some of these systems were lacking Hα emission while still exhibited X-ray emission, which suggest they could be part of a possible hidden population of symbiotics that have been left unnoticed. We also looked at the optical spectra taken of the counterpart star in CX44, a candidate LMXB with an ~ 8 hour orbital period, and create radial velocity curves of the counterpart star. The radial velocity and orbital period were used to estimate the mass of the accretor, which was identified as being a white dwarf, making CX44 a cataclysmic variable system.



Committee Chair

Hynes, Robert