Kelsie Taylor Qualifying Exam

Abstract: Pulsar Timing Arrays (PTAs) are well-known in searches for a stochastic gravitational wave background (SGWB), as an SGWB induces specific angular correlations in pulsar timing residuals, known as the Hellings-Downs curve. However, the science of PTAs is extendable past this single application. We first discuss intersections between PTAs and relative astrometry for the purposes of SGWB detection, focusing on current developments in astrometric mock data and the future goals of a joint analysis between PTAs and astrometry. We then examine PTAs as a probe of 1e−24 eV – 1e−20 eV mass ultralight scalar dark matter (ULDM), discussing progress on extending previous analyses for both linear and non-linear couplings.