Graduate Program Events |
Events During the Week of August 17th through August 24th, 2025
Monday, August 18th, 2025
- Academic Calendar
- Faculty contract year begins
- Abstract: *Note: actual end time may vary.* CONTACT: admin@secfac.wisc.edu
- PhD Orientation
- Time: 9:00 am - 12:30 pm
- Place: 2241 Chamberlin
- Host: Sharon Kahn
- Preliminary Exam
- 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
- Qualifying Exam Study Hall
- Time: 1:00 pm - 2:30 pm
- Place: 3320 Chamberlin
- Host: Jim Reardon
Tuesday, August 19th, 2025
- Grad Professional Development
- Time: 10:00 am - 12:00 pm
- Place: 2241 Chamberlin
- Host: Sharon Kahn and Alice Kwok
- Qualifying Exam Study Hall
- Time: 1:00 pm - 2:30 pm
- Place: 3320 Chamberlin
- Host: Jim Reardon
Wednesday, August 20th, 2025
- Thesis Defense
- Searches for transient astrophysical neutrino sources in real time with the IceCube Neutrino Observatory
- Time: 10:30 am - 12:30 pm
- Place: B343 Sterling
- Speaker: Jessie Thwaites, Physics PhD Graduate Student
- Abstract: Multi-messenger astrophysics is a powerful tool for understanding the most energetic sources in the universe. Although IceCube has discovered a flux of extragalactic neutrinos, the sources of the vast majority of those neutrinos remain a mystery. Several classes of astrophysical transients are proposed sources of neutrino emission. By searching for neutrinos from these sources in realtime, we can identify multi-messenger sources rapidly to inform follow-up by other telescopes. In this thesis, a broad range of transients are analyzed, including gravitational wave transients, nearby supernovae, bright gamma-ray bursts, and novae. Compact object mergers, detected by the LIGO-Virgo-KAGRA detectors, may produce neutrinos alongside their gravitational wave emission. The hundreds of times smaller localization area of neutrino track events can inform follow-up by other observatories in realtime from these sources, increasing the probability of identifying the multi-messenger source. Another exciting transient event which occurred in October 2022 was the brightest gamma-ray burst ever recorded, GRB 221009A. We search for neutrinos from this GRB in realtime and in an archival search leveraging the full energy capabilities of the detector. We set the strongest constraints on neutrino emission from GRBs using this single burst, due to its bright electromagnetic flux and the IceCube non-detection. Finally, we search for sub-TeV neutrinos from nearby and bright novae in both archival data and in realtime. In archival data, we search for neutrinos from the nova RS Ophiuchi in its 2021 outburst, the only nova so far detected to TeV gamma-ray energies. This analysis can be applied to the upcoming eruption of nova T Coronae Borealis, which is both closer and brighter in optical flux than RS Oph, meaning the expected neutrino emission is several times higher than that of RS Oph. IceCube will be able to search for neutrino emission from this nova in realtime using two neutrino datasets spanning GeV-PeV neutrino energies.
- Host: Justin Vandenbroucke
- All Grad lunch/recess
- Time: 12:00 pm - 1:00 pm
- Place: Bascom Hall in front of Birge Hall
- Abstract: All Physics Grad students (new and continuing, PhD and MSPQC) are welcome to join for picnic lunch on Bascom Hill outside of Birge (or inside the Birge lobby if the weather doesn't cooperate).
- Host: Sharon Kahn
- Qualifying Exam Study Hall
- Time: 1:00 pm - 2:30 pm
- Place: 3320 Chamberlin
- Host: Jim Reardon
Thursday, August 21st, 2025
- Qualifying Exam Study Hall
- Time: 1:00 pm - 2:30 pm
- Place: 3320 Chamberlin
- Host: Jim Reardon
- Preliminary Exam
- 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
- Qualifying Exam Study Hall
- Time: 1:00 pm - 2:30 pm
- Place: 3320 Chamberlin
- Host: Jim Reardon
Saturday, August 23rd, 2025
- No events scheduled
Sunday, August 24th, 2025
- Academic Calendar
- Graduate School Summer 2025: Doctoral degree deadline
- Time: 11:55 pm - 12:55 am
- Abstract: CONTACT: 262-2433, gsacserv@grad.wisc.edu