Macquarie University NSW 2109
Generating models that can be tested with observations
These research projects are looking at models of stellar evolution, planet formation, galactic centre magnetic fields and black holes.
Learn more about the projects we are undertaking, the researchers engaged in them and who you can contact to get involved.
Physical black holes: Role of the horizons
Astrophysical black-hole candidates are observed as dark, massive, ultra-compact objects and their key feature is taken to be a horizon. However, having a horizon is not just a label: it requires a light-trapping boundary to form under specific conditions on geometry, matter and quantum effects. Physical black holes (ΦBHs) take this requirement literally by asking what it takes for an apparent horizon to have formed by now for a distant observer and what consequences follow for collapse, semiclassical physics and observable signals.
Project 1: Axially symmetric models
Realistic astrophysical black holes rotate, so the ΦBH framework must be extended beyond spherical symmetry. This project will investigate which axially symmetric ΦBH geometries are consistent with finite formation time, regularity and constraints from quantum field theory, especially quantum energy inequalities. The goal is to classify viable spinning ΦBH models and determine how their near-horizon structure differs from conventional Kerr black holes and horizonless compact objects.
Project 2: Collapse and quantum effects
This project will ask whether ΦBHs can form under known physics. The focus will be semiclassical gravity, where spacetime geometry is classical but matter is described by quantum field theory. Key issues include Hawking radiation, backreaction, negative energy densities and the constraints imposed by quantum energy inequalities. The project may also use low-dimensional quantum-gravity models as controlled settings for testing whether ΦBH analogues can form and evaporate consistently. Exotic objects, like wormholes, are a possibility.
Project 3: Observable signatures of physical black holes
This project will investigate whether ΦBHs produce observable signals that distinguish them from conventional black holes and horizonless compact objects. Possible signatures include changes in quasinormal modes, late-time tails, light rings, shadows and binary dynamics. The project will use interpolation and perturbation methods to connect near-horizon ΦBH structure to distant observables, with gravitational-wave and black-hole-shadow measurements providing the main motivation.
To get involved in this project, contact: Daniel Terno
Stellar collisions
Powerful telescopes have recently begun monitoring the sky every night, creating the first detailed ‘movie’ of the night sky and revealing short-timescale ‘flashes’.
Some of these are due to stellar pairs interacting with one another, creating energetic explosions now finally observed.
Yet explaining what goes on during these interactions is not so easy and many mysteries remain unsolved, including the understanding of supernovae, gamma ray bursts and the emission of detectable gravitational waves.
Choose from sub-projects spanning the interaction of planets with their mother star to the interaction of massive stars on eccentric orbits. See more information about this project.
To get involved in this project, contact: Orsola De Marco
The structure and evolution of disks around evolved binary stars and its implications on binary evolution
This study involves the intertwined stories of stellar and binary evolution.
We have established that stable circumbinary disks exist around dying binary stars. However, the role played by the circumbinary disk during the evolution of the star remains elusive.
This project is aimed at investigating these second-generation protoplanetary disks around evolved binaries. We are using high-angular-resolution imaging with the state-of-the-art Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument on the European Southern Observatory’s Very Large Telescope in Chile.
The ultimate goal of this research is to understand disk evolution and quantify the impact of these disks on the binary evolution of the central objects.
To get involved in this project, contact: Devika Kamath