Date of Award
Doctor of Philosophy (PhD)
The current generation of gamma-ray instruments have produced a treasure trove of astrophysical discoveries. Among them are a new class of objects tentatively designated high-mass gamma-ray binaries (HMGBs). Thought to be systems containing the colliding wind of a massive star and a young pulsar, these objects are distinguished by emission >1 MeV dominating their spectral energy distributions. We present a multiwavelength study of a newly detected gamma-ray source, HESS J1844-030, utilizing Chandra, Fermi, and VERITAS to show that its spatial, spectral, and flux variability properties are compatible with a classification as a HMGB. The current generation of instruments have identified only 8 high-mass gamma-ray binaries. For progress in understanding HMGBs as a source class to continue, a future large-effective area GeV observatory is necessary. The Advanced Particle-astrophysics Telescope (APT) is a proposed instrument with broad energy coverage and large effective area, holding the potential to probe the population of all such sources to beyond the center of the Milky-Way. Over the course of its development at Washington University, prototype designs of the imaging calorimeter component have been tested in 2018 at the CERN North Area beam line and at altitude on-board the 2019 SuperTIGER-2.3 flight. Exposure to the 150 GeV/nuc A/Z = 2.2 CERN SPS beam shows charge resolution up to Z = 12 and linearity in the signal response up to lead. The 2019 SuperTIGER-2.3 flight demonstrates the successful integration of the electronics design, reconstruction of saturating pulses from the tail of the scintillation signal, and position localization within the imaging calorimeter plane to < 3 fiber widths. Using the simulated sensitivity of the full 3 m × 3 m APT instrument, the ability to extend the observational horizon for HMBGs performance is examined.
Chair and Committee
James H. Buckley Manel Errando
Jeremy Buhler, Ramanath Cowsik, Henric Krawczynski,
Hughes, Zachary Daniel, "Toward an Understanding of High-mass Gamma-ray Binaries: An Investigation Using Current Observatories and the Development of a Future GeV Instrument" (2021). Arts & Sciences Electronic Theses and Dissertations. 2368.