School of Physics Thesis Defense

Pranav Dave ; Time-Variability & Primordial Black Hole Evaporation: Astrophysical Neutrino Studies

Presenter: Pranav Dave
Title: Time-Variability & Primordial Black Hole Evaporation:  Astrophysical Neutrino Studies
Date: Tuesday, April 18, 2023
Time: 3:00 p.m.
Location: Howey N110
Via Zoom:

Dr. Ignacio Taboada, School of Physics, Georgia Institute of Technology (advisor)
Dr. David Ballantyne, School of Physics, Georgia Institute of Technology
Dr. Nepomuk Otte, School of Physics, Georgia Institute of Technology
Dr. John Wise, School of Physics, Georgia Institute of Technology
Dr. Carlos Argüelles-Delgado, Department of Physics, Harvard University

Our current understanding of the universe stems from observations across the electromagnetic spectrum as well as additional messengers, such as gravitational waves, cosmic rays, and neutrinos. Particularly, we have observed a high-energy astrophysical diffuse neutrino flux using the IceCube Neutrino Observatory at the South Pole for the past 10 years. However, the specific sources that contribute to this flux are not known. More recently, IceCube reported evidence of neutrino emission from the nearby AGN and Seyfert II galaxy NGC 1068. In this work, I present a new method to ask: Is NGC 1068 a time-variable neutrino source? By applying this method to an identical data sample that was used to report the evidence of emission, I conclude that the neutrino emission from NGC 1068 is consistent with a steady source. This new method can be applied to future candidate point sources observed by IceCube and serves as a source characterization tool.

Hawking radiation elegantly unifies quantum field theory, general relativity, and thermodynamics. Primordial Black Holes (PBHs) offer a way to directly observe Hawking radiation as the hole evaporates over the age of the universe. No evidence for Hawking radiation or PBHs has been reported yet and PBHs have been extensively studied as Dark Matter (DM) candidates in the past. In this work, I present a search for high-energy neutrino emission from an individual PBH that is evaporating in our local universe using data collected by IceCube. This is the first time high-energy neutrinos have been used to search for Hawking radiation from an evaporating PBH. Due to null detection in this search, I present an upper limit to the PBH evaporation density rate and compare it to existing limits from gamma-ray telescopes.


Event Details


  • Date: 
    Tuesday, April 18, 2023 - 3:00pm to 4:00pm

Howey N110 (and via ZOOM)