Date of Award
Master of Science (MS)
Globular clusters are the oldest objects in the Milky Way, serving as probes of early galactic evolution due to their chemically uncontaminated history. Compact binaries act as an internal energy source through their dynamical interactions, and measuring the types of X-ray binaries within a cluster provides an understanding of its stellar population and dynamics, as stellar collisional frequencies have been correlated to the number of X-ray sources detected in globular clusters. Compact binaries can be found by correlating X-ray positional data with optical imaging data. In this project, optical fluxes of sources from archival HST images of NGC 5904 have been measured using a DOLPHOT PSF photometry in the optical and Hydrogen-alpha (H↵). A data analysis pipeline has been developed to process of tens of thousands of objects using Awk, Python and DOLPHOT. We identify potential optical counterparts of X-ray sources detected with the Chandra X-Ray Observatory based on their positions as outliers in color-color diagrams and color-magnitude diagrams. Seven out of nine Chandra X-ray sources within the field of view (FOV) of our HST images of NGC 5904 contain such outliers. Furthermore, X-ray fluxes of the sources in NGC 5904, along with DOLPHOT photometric fluxes are also used to determine the X-ray to optical flux ratio, which is used to identify the types of compact X-ray binaries in NGC 5904. We find four out of seven compact X-ray binaries to be Cataclysmic Variables, two to be Active Binaries, and one to be a Millisecond Pulsar. This provides details of the inner workings of NGC 5904, which has a high number of X-ray sources and a large collision rate. Support for this research from the Illinois Space Grant Consortium is gratefully acknowledged.
Bhalotia, Vanshree, "Optical and X-Ray Studies of Compact X-ray binaries in NGC 5904" (2018). College of Science and Health Theses and Dissertations. 279.