At UCC Dr Mark Kennedy studies compact objects in binary star systems. He is interested in what these systems can tell us about the nuclear equation of state and whether the observed mass gap between neutron stars and black holes in our Galaxy is real. LISA will be able to detect new neutron star and black hole binaries to further inform our understanding. As a member of the ULTRACAM team, Mark is involved in the precise timing of ultra compact binaries with periods in the range of minutes. These systems are losing a significant amount of their angular momentum through gravitational wave emission and can be used as verification binaries for LISA once it is operational.
Dr Michael Tremmel uses high resolution cosmological simulations to study the formation, growth, and dynamical evolution of massive black holes in galaxies. Using large-scale simulations like Romulus, his group predicts what the population of MBHs (and binary MBHs) is across different environments over cosmic time. His group also uses zoom-in simulations of individual galaxies to study MBHs at unprecedented detail. Such simulations are crucial in predicting and understanding the nature of the MBH binaries and mergers LISA will be detecting.
The image above shows a zoom-in simulation of an early merger between low mass galaxies resulting in a binary MBH (black holes shown as x’s). Mergers like these will likely make up the majority of events detected by LISA and can provide invaluable clues to the formation and early evolution of MBHs in the Universe.