Gravitational Waves student research projects

Lensing of gravitational waves and precision localization of binary black hole mergers

Since a few years, the LIGO-Virgo network of gravitational wave detectors has been observing gravitational waves on a regular basis, including at least one signal from a binary neutron star merger, but most of them coming from binary black holes. Just like electromagnetic waves, gravitational waves can undergo gravitational wave lensing, whereby a galaxy or galaxy cluster in the line of sight between source and observer produces multiple "images" of the same source. In the case of gravitational waves, the images undergo time delay, arriving at the detectors with time lags of days to months. In the intervening time, the Earth will have rotated, causing the detectors to have different orientations when a second image is received. This effectively doubles the number of detectors in the network, which in turn allows for accurate localization in space of a binary black hole merger, possibly to the point that the host galaxy of the event can be identified. With expected upgrades of the LIGO and Virgo detectors, it is likely that towards the middle of this decade, one or more lensed events per year will be seen. In anticipation of this, the aim of the project is to set up a data analysis framework that would identify such events in a robust way, taking into account various potential causes of measurement bias. (contact: C. Van Den Broeck)

Searches for gravitational waves from compact binary coalescence

Searches for gravitational waves from the mergers of black holes and neutron stars have been extraordinarily successful in the last four years. We are now beginning to study a population of heavy stellar-mass black holes in detail, including understanding how these systems came to form and whether they are consistent with general relativity. Additionally, the detection of binary neutron star mergers is allowing us to probe their extreme matter. However, we’ve only just scratched the surface of possible signals and the new physics they’d allow us to study. The detection of highly spinning and precessing systems would allow us to perform black hole population statistics to an extraordinary degree of accuracy. Detection of sub-solar mass systems would provide evidence of dark matter. However, these searches are difficult because they require us to work in high-dimensional spaces and develop new statistical methods. There are possibilities for several projects that involve the development and implementation of these new searches as well as the interpretation of the results, particularly in terms of the physics describing compact binary mergers. (contact: S. Caudill)