Stefano Schmidt, PhD at Nikhef, will defend his thesis Tuesday 20 May 2025 at 12.15 at the Utrecht University.
Searching for Precessing Black Hole Binaries in Gravitational-wave Data (pdf)
When two black holes orbit each other and eventually collide, they can send out ripples in space called gravitational waves. If the black holes are spinning in different directions instead of neatly aligned, their orbits can wobble or precess—a bit like a spinning top. Studying these wobbling systems could help scientists learn more about how far away the collision happened and what the black holes were like before they merged.
However, spotting these signals in the data is very tricky. Most search methods assume the black holes are aligned, so they often miss or misinterpret precessing signals. In this study, we made improvements to a key search tool used in gravitational wave detection to better find these harder-to-detect precessing black hole signals.
After testing the new version of the tool, we searched for this special type of black hole collision in data from the LIGO and Virgo detectors. In the end, we picked up 30 gravitational wave events that had already been found by other studies, but we didn’t discover any new ones. This result helped us estimate how often these rare, wobbling black hole mergers might happen. Based on our findings, it seems unlikely that there’s a large hidden group of these precessing systems that other searches have missed.
The PhD defense will take place in the Academiegebouw, Domplein 29, 3512 JE Utrecht.
More information and a link to the livestream on the website of the Utrecht University.
Supervisor: prof. dr. C.F.F. Van Den Broeck
Co-supervisor: dr. S.E. Caudill
contact: Stefano Schmidt
