X-rays from Warped Black Hole Accretion Disks

• Main Author: Abarr, Quincy
• Format: Text
• Language: English
• Published: Washington University Open Scholarship 2020
• Subjects: Astrophysics and Astronomy; Physics; Antarc*; Antarctica
• Online Access: https://openscholarship.wustl.edu/art_sci_etds/2301; https://openscholarship.wustl.edu/cgi/viewcontent.cgi?article=3352&context=art_sci_etds

In this thesis, I present the results from my research to better understand accretion onto black holes and neutron stars based on spectropolarimetric X-ray observations. I have developed a general relativistic ray-tracing code which simulates X-rays from warped accretion disks around black holes. I used this to predict the polarization of the thermal X-ray emission and the energy spectrum the reflected power law emission. Both of these can be used to measure properties of black hole systems, such as the spin parameter and the inclination of the observer to its spin axis. My results enable the measurement of these parameters with improved accuracies and with a different set of systematic errors. The methods discussed can be applied to the data of existing X-ray satellites, such as Chandra and XMM-Newton, and upcoming spaceborne missions, such as the Imaging X-ray Polarimetry Explorer (IXPE) and the X-ray Imaging and Spectroscopy Mission (XRISM). My work also included optimization and deployment of the balloon-borne X-Calibur experiment for its 2018/2019 long duration balloon flight from McMurdo, Antarctica. Results from this flight allowed me to study the light curve and polarization of the hard X-ray emission from the accreting pulsar GX 301-2. I have also contributed to the research and development for its successor, called XL-Calibur, which will observe pulsars and black holes during a northern hemisphere flight in the next few years.