“ Accretion Disk Contributions to the Diffuse Neutrino Background ”
This work aims to present predictions for the detection of accretion disk relic neutrinos at both Super Kamiokande and the upcoming Hyper Kamiokande. The paper begins by introducing a slew of concepts related to the diffuse neutrino background for accretion disks. This is built upon by deriving the diffuse neutrino spectra, flux, and differential detection rates before arriving at annual event rates. Three source scenarios are used: NS-NS mergers, BH-NS mergers, and collapsars. Merger rates are taken from population synthesis simulations by Dominik et al. and cover a wide range of galactic evolution scenarios. Similarly, collapsar rates are from Yüksel et al. and are based upon Swift’s gamma ray burst data. These are combined with the steady Chen and Beloborodov model and the dynamic Just et al. disk models. Both models account for a variety of thermodynamical and relativistic factors while presenting both spinning and stationary black holes. The result is presented as bands defined by optimistic and pessmistic cases. As a result, a range of predicted event rates at both detectors is presented. It is found that collapsar accretion disks are generally larger relative to supernovae, while both merger scenarios are smaller. It is shown that the combination of various scenarios can beplaced in contrast to supernova diffuse neutrinos at higher MeV energies. From these results it is clear that the detection of accretion disk neutrinos is feasible with upcoming facilities. From this point, models may be refined or improved based upon detection results.
- Dr. Joanne O'Meara, Chair
- Dr. Liliana Caballero, Co-Advisor
- Dr. Carl Svensson, Co-Advisor
- Dr. Huan Yang