An archival search for white dwarf pulsars

  • Author / Creator
    Ridder, Margaret
  • AR Sco is the first known white dwarf pulsar and currently there is no definitive model for its emission or evolution. This type of binary system could be a critical step in the formation of magnetic cataclysmic variables, a type of accreting white dwarf/M dwarf binary system. In this thesis, I outline a new method of finding AR Sco twins. Since AR Sco was originally classified as a δ Scuti pulsating variable star, I examine catalogs of these stars from optical surveys. In these catalogs, I find possible candidates that are more blue in color and are dim compared to the rest of the sample since these qualities mimic those of AR Sco. We apply these selection criteria to catalogs from the All-sky Automated Survey for Supernovae, the Zwicky Transient Facility, and Rodriguez et al. 2000. In addition, I analyze Gaia data using a similar method, but this was limited by the relative lack of time-series data. I also try to identify X-ray and radio counterparts to our possible candidates. Modeling the distribution of δ Scutis in the Galaxy, I find that our catalogs are the most complete for high-amplitude variables. Using the high-amplitude subset of our possible candidates, I calculate an upper and lower limit on the number of δ Scutis in the Galaxy that could be misidentified AR Sco twins. In the future, I will ask for follow-up time on Chandra X-ray Observatory, Very Large Array, and Gemini to study possible candidate twins.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.