Senior Research Fellowship: Astroparticle Physics with the IceCube Neutrino Observatory at the South Pole and a High-Energy Extension - 3rd term

Cosmic explosions produce high-energy particles, dubbed cosmic rays, that are detected on Earth and may provide insight in the physical processes underlying these cataclysmic events. Neutrinos are the only messengers that can provide information about the central cores of cosmic accelerators like Gamma Ray Bursts (GRBs) and Active Galactic Nuclei (AGN), which are believed to be the most powerful cosmic phenomena and the sources of the most energetic cosmic rays, known as UHECR. Analysis of the data from the IceCube detector has provided a flux upper limit for high-energy neutrinos from GRBs which is well below theoretical expectations, indicating that the underlying processes are currently not well understood and that GRBs are not the only sources of the observed UHECR. Furthermore, in 2013 IceCube discovered a flux of high-energy cosmic neutrinos, but their sources are yet unknown, apart from a single observation in september 2017 of a flaring Blazar.
New IceCube data and foreseen detector extensions will enable a more detailed investigation to resolve these mysteries. In view of this, innovative analysis methods are being developed at the VUB to study both GRBs and AGN with unprecedented sensitivity. In addition to this, new radio detection techniques are being explored to increase the detection volume, which allows a detailed investigation of the cosmic neutrino spectrum and reach out to higher neutrino energies. It is expected that these new approaches will reveal the nature of these mysterious phenomena and the
sources of the cosmic high-energy neutrinos, while also the extension to higher energies will allow us to explore new, unknown, territory.