Biography

Research interests: supernova Cosmology, redshift accuracy, systematic errors and their effects on cosmological parameters

I am a PhD student working with Professor Tamara Davis (UQ) and Assistant Professor Daniel Scolnic (Duke University) on the redshifts used in supernova cosmology. Supernovae are so bright that we can see them out to billions of light years away which is useful for probing how the universe has expanded over time, and what components it is likely made of to cause such expansion. My work mostly revolves around how to most accurately measure and use the recession velocity of the galaxies that host supernovae, which we observe via their redshift (their velocity away causes any emitted light to become redder).

I am a member of the Dark Energy Survey (DES), Australian Dark Energy Survey (OzDES), and the Dark Energy Spectroscopic Instrument (DESI) survey. I am also currently in charge of the ‘Global Redshift Catalogue’ which is a collection of all spectroscopic redshifts in the DES/OzDES supernova monitoring fields.

As part of my research I have led two observing programs using the 2.3 metre telescope and the Anglo Australian Telescope at Siding Spring Observatory, NSW. With the 2.3m telescope, we used the Wide Field Spectrograph (WiFeS) instrument specifically to measure a swathe of sky/target instead of a single point. We were able to measure the redshifts of over 200 nearby supernova hosts. An example observation of the famous Antennae Galaxies, which hosted a supernova in 2007, is shown below. Each pixel in the inset is a separate spectrum from which we can measure an individual redshift.

Another example below is a galaxy that hosted a supernova in 2005. This galaxy is not entirely face-on, so we can see its rotation through the slight difference in recession velocity of each individual pixel in the gif. The gif steps through wavelength around a particular bright emission line, showing that the top left of our aperture is more redshifted than the bottom right. The region we can see appears to be rotating at roughly 70 km/s.