Queen's 2015 Nobel Prize in PhysicsPatrick Hatch has successfully defended his PhD defence. His thesis鈥檚 title is 鈥淣eutrino emission from extreme high-energy peaked BL Lac objects". He carried out his research under the supervision of Prof. Kenneth Clark and Prof. Nahee Park.
This thesis makes contributions across three high-energy astrophysics projects centred on high-energy neutrino detection and research. The first project examines bioluminescent background noise for P-ONE, a proposed neutrino telescope in the Cascadia Basin in Canada, and finds that bioluminescent flashes significantly elevated photon rates above baseline for nearly a third of the observation period. The second project develops a machine-learning-based event splitter for IceCube, a cubic-kilometre neutrino telescope located at the South Pole, to isolate individual muon signals from the ~10% of events that contain multiple simultaneous cosmic-ray muons. The third project uses 12.3 years of IceCube data to search for neutrino emission from extreme high-energy peaked BL Lac objects (eHBLs), a blazar subclass whose emission hints at hadronic processes; assuming proton-proton interactions drive all gamma-ray output, IceCube can constrain those interactions at 90% confidence for five TeV-detected eHBLs, with sensitivities reported for a broader sample of 167 sources lacking TeV measurements.
The selected plot shows the exclusion curves representing the spectral constraints on the high-energy neutrino flux from eHBL 1ES 0229+200 based on IceCube sensitivity. The constraints are estimated assuming that the observed gamma-ray flux is 100% hadronic and arises from proton-proton inelastic interactions (pp model).
