Preliminary Exam |
Events During the Week of August 17th through August 24th, 2025
Monday, August 18th, 2025
- Searches for astrophysical neutrinos from compact object mergers and gamma-ray active galactic nuclei with IceCube
- Time: 12:00 pm - 2:00 pm
- Place: 5310 Chamberlin
- Speaker: Sam Hori, Physics PhD Graduate Student
- Abstract: I will present my work using the IceCube Neutrino Observatory to search for astrophysical neutrino production. I will present an analysis of compact binary mergers detected by the LIGO-Virgo-KAGRA gravitational wave detectors with a cascade dataset. I will also present population constraints on the neutrino flux of GeV gamma-ray bright active galactic nuclei detected by the Fermi Large Area Telescope. In addition to the results of these analyses, I will discuss improvements to the IceCube real-time program, which will improve real-time searches for the sources of astrophysical neutrinos and the information IceCube provides to the multi-messenger community. The creation of posterior skymaps will enable improved follow-up by other telescopes by providing a probabilistic localization that accounts for both the IceCube neutrino information as well as the prior knowledge of a potential multi-messenger event obtained by other observatories. I will also discuss work towards enabling an improved cascade dataset to be used in real-time analyses, including the maintenance of IceCube filters as well as a pipeline to process events rapidly enough for real-time analyses.
- Host: Justin Vandenbroucke
Tuesday, August 19th, 2025
- No events scheduled
Wednesday, August 20th, 2025
- No events scheduled
Thursday, August 21st, 2025
- Search for the Highest Energy Neutrinos in IceCube
- Time: 4:00 pm - 6:00 pm
- Place: 5280 Chamberlin
- Speaker: Maxwell Nakos, Physics PhD Graduate Student
- Abstract: Recently, KM3Net has detected a neutrino candidate with a best fit neutrino energy of 220 (-110,+570) PeV, while the highest energy event from IceCube has a best fit neutrino energy of 11.4 (-2.53,+2.46) PeV. Due to the absorption from the Earth, neutrinos with energies greater than 10 PeV are likely to originate from the horizontal and downgoing directions, where there is a large, high energy atmospheric muon background from cosmic rays.
To address this, I develop neural networks to improve background rejection for downgoing tracks from the southern sky, recovering throughgoing neutrinos typically discarded due to high atmospheric muon contamination. These events enable a search for extremely high-energy neutrinos, which are incorporated into a diffuse combined fit - including cosmogenic, astrophysical, and atmospheric components - to probe the apparent tension between KM3NeT and IceCube observations at the highest energies.
In parallel, I am also developing a transient analysis looking for spatial and timing correlations between ultra-high-energy photon candidates detected by the Pierre Auger Observatory and multi-flavor neutrinos detected by the IceCube Neutrino Observatory, the first search for ultra-high-energy transient sources combining neutral particle information from UHE photons and neutrinos. - Host: Lu Lu
Friday, August 22nd, 2025
- No events scheduled