Abstract

The strong gravitational field around black holes provides a unique laboratory for investigating the behavior of matter and radiation under extreme conditions. As matter accretes, the interplay between the accretion disk, hot corona, and surrounding stellar environment produces complex spectral and polarimetric X-ray signatures. Thus, X-ray spectropolarimetry has become a powerful tool for constraining the accretion geometry. Building on these advances, this dissertation integrates theoretical modeling, observational data analysis, and instrumentation development to address open questions in high-energy astrophysics. On the theoretical side, relativistic ray-tracing simulations test the truncated disk-hot inner flow accretion geometry against observations of Cygnus X-1, identifying the physical conditions required to explain the data. On the observational side, a statistical framework is developed to disentangle geometric orbital modulation from spectral variability in IXPE polarimetry of Cygnus X-1, placing constraints on scattering off the stellar companion and its wind. On the instrumentation side, the challenge of background suppression for cryogenic X-ray and gamma-ray detectors is addressed through simulation and laboratory testing of active anti-coincidence shielding inside a dilution refrigerator, advancing the technology needed for next-generation high-energy observatories.

Committee Chair

Henric Krawczynski

Committee Members

Erik Henriksen; Jeremy Schnittman; Manel Errando; Yajie Yuan

Degree

Doctor of Philosophy (PhD)

Author's Department

Physics

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

4-27-2026

Language

English (en)

Author's ORCID

https://orcid.org/0009-0002-2488-5272

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