Associate Professor Jeff Cooke
I am currently leading research in the areas of high redshift galaxies (in emission and absorption), high redshift supernovae, and fast transients. The fast transient work includes the search for electromagnetic counterparts to gravitational waves as part of the Centre of Excellence for Gravitational Wave Discovery (OzGrav), in which I am a Chief Investigator.
I conduct and collaborate on large, deep imaging and spectroscopic surveys to detect and study galaxies and supernovae at high redshift. The surveys aim to better understand galaxy evolution, their properties and environments, the supernovae within them, and the impact galaxies had on cosmic reionisation. Some highlights of the many programs I am leading are that we have identified a previously overlooked population of galaxies (the Lyman continuum galaxies) that may have been responsible for the bulk of ionising photons in the early Universe, we have uncovered surprising relationships between the spectral features of galaxies and a number of internal and environmental properties, and we have observed absorption systems illuminated by background galaxies that have provided the first measurements of their most fundamental properties (size and mass) which have remained elusive in the 40 years since their first discovery. In addition, I pioneered a technique to detect supernovae in high redshift galaxies and at distances far greater than has been previously achieved, including super-luminous supernovae, some of which, may be observational examples of a long-theorised third type of supernova based on the pair-instability process. Our most distant discoveries occurred when the universe was only about 10% its current age. Because many of the first generation of stars (Population III stars) are believed to result in pair-instability supernovae, we now have the capability and may be detecting the deaths of the very first stars.
I developed the Deeper, Wider, Faster (DWF) program to search for fast transients, such as supernova shock breakouts, kilonovae, counterparts to fast radio bursts (FRBs), and other events with seconds-to-hours durations that have remained elusive largely due to instrument and technological barriers. Many of these events are predicted to generate gravitational waves. DWF is a new approach that overcomes previous obstacles by coordinating simultaneous, fast-cadenced, deep, multi-wavelength observations using major facilities (e.g., Parkes, Molonglo, Swift space telescope, CTIO DECam), processing the data in seconds using the Swinburne supercomputer, and identifying fast transients in real-time using advanced software, machine learning, and visualisation technology. The real-time analysis enables deep, rapid ToO spectroscopy of the events and their host galaxies acquired within minutes of detection using 8m-class telescopes (e.g., Gemini-South and potentially Keck and VLT). Finally, DWF employs a network of 1-10m facilities for hours-to-days later follow-up imaging and deep spectroscopy, that includes the SALT, AAT, ATCA, SkyMapper, AST3 in the Antarctic, and the Zadko telescopes. DWF aims to resolve the FRB mystery with its multi-wavelength, fast real-time analysis approach and is a key OzGrav program to search for electromagnetic counterparts to gravitational waves.