Astrophysics and Gravitation
Research activities in the astrophysics and gravitation group at the University of Guelph cover a broad range of subjects, including high-energy nuclear astrophysics, the physics and astrophysics of black holes and neutron stars, the dynamics of compact binaries, the design of future gravitational-wave detectors, and fundamental aspects of relativistic gravitation. Much of this work is carried out in the context of the emerging area of multi-messenger astronomy, which combines information carried by electromagnetic radiation (in all bands), neutrinos, and gravitational waves. The group enjoys close ties with Perimeter Institute (Yang has a joint appointments) and with the Canadian Institute for Astrophysics.
The research activities of Liliana Caballero focus on the role of nuclear reactions, neutrino interactions, and nuclear forces on the synthesis of elements and the evolution and mergers of compact objects (white dwarfs and neutron stars), as well as accretion disks around black holes. These stellar environments exhibit strong gravitational fields and extreme thermodynamic conditions, and constitute a unique extraterrestrial laboratory to probe our understanding of the fundamental forces of nature. Caballero's group provides detailed predictions of signals emerging from these systems, which will be observed by various telescopes, neutrino detectors, and gravitational-wave observatories.
from matter accreting into a rotating black hole. The color scale represents the local temperature.
Huan Yang's research work is also grounded in the fundamental processes associated with gravitational-wave and multi-band/multi-messenger astronomy. The work focuses on the dynamics and gravitational-wave emission of black-hole and neutron-star systems, with the goal to extract specific predictions that will be verified in observations by ground-based and space-based gravitational-wave detectors. The work also aims to exploit these observations to gather information about the population of black-hole and neutron-star binary systems in the Universe, their formation scenarios, and the fundamental physical processes involved during their mergers. Yang's group initiated and continues to perfect the design of high-frequency gravitational-wave detectors to probe neutron-star physics, in an effort to plan for the construction of third-generation detectors beyond LIGO and Virgo.
The orbit of the stellar-mass black hole is perturbed by another stellar-mass black hole nearby.
The research efforts of Eric Poisson cover a range of topics in general relativity, including the perturbation theory of black holes and neutron stars, the electromagnetic and gravitational self-force acting on particles moving in a curved spacetime, and the generation and propagation of gravitational waves. The main focus of Poisson's group is on tidal interactions of compact binaries in the context of gravitational-wave astronomy. The tidal interaction affects the orbital motion and the emission of gravitational waves, and the tidal imprint on the waves can thus be measured. Because the tidal deformation of a body is sensitive to the details of internal structure, gravitational-wave observations will eventually reveal intimate details of the physics of a neutron star, in particular the nature of its equation of state.
The compact star exerts tidal forces on the black hole, and vice versa.
Theorists
Liliana Caballero
Eric Poisson
Huan Yang