Ayatri Singha, PhD at Nikhef, will defend her thesis Thursday 4 April 2024 at 10.00 at Maastricht University.
“Gravitational Wave Astronomy With Current and Future Generation Detectors”
Gravitational waves are created when massive objects, such as neutron stars or black holes, accelerate and alter the fabric of space-time. In binary systems, where these objects orbit each other, their interaction sends ripples of space-time through space as gravitational waves. These waves are difficult to detect because they interact very weakly with matter. It is like trying to catch a whisper in a noisy room. Scientists use special detectors to listen for these whispers, but they have to deal with a lot of background noise that makes it hard to hear the gravitational waves. It’s a bit like trying to pick out a single voice in a crowded room.
The first half of the dissertation looked at a specific type of noise called seismic Newtonian noise. This noise occurs when seismic waves cause local variations in soil density, resulting in additional gravitational forces on the detector’s test masses, causing them to move. This noise can be a problem for detectors designed to pick up very faint signals, especially those from things like pulsars and massive black hole mergers. To overcome this challenge, methods to reduce Newtonian noise have been explored. One approach investigated in this dissertation is to create a recess around the test mass. This technique has significant implications for the design of future surface detectors so that Newtonian noise can be minimized. To reduce unwanted noise at specific locations, we need to understand where it’s coming from. This work includes detailed analyses of seismic activity that reveal important features of the seismic field.
Third-generation detectors like the Einstein telescope and Cosmic Explorer will be better at detecting gravitational waves than the ones we have now. For the Einstein telescope, we are trying to decide between two shapes: one shaped like the letter “L” and the other shaped like a triangle. Figuring out which shape is best is really important for doing good science. In the second part of the dissertation, the effects of the geometry of the detectors was studied. The triangular detector setup is advantageous because it includes an additional detector that helps cancel out the actual signal from the background noise. The ability to cancel out signals from background noise can improve our understanding and calibration of the detector. This capability has been demonstrated in this dissertation.
“Gravitational Wave Astronomy With Current and Future Generation Detectors” (pdf)
The PhD defense will take place at the administrative office of Maastricht University, Minderbroedersberg 4-6, 6211 LK Maastricht.
More information on the website of the Maastricht University.
Supervisor: prof. dr. Stefan Hild
Co-supervisor: dr. Stefan Danilishin
Contact: Ayatri Singha