Caroline Foster

Welcome to my homepage. I am A/Prof Caroline Foster (most people just call me Caro) and I am an astronomer. I have spent hundreds of nights at remote astronomical sites under pristine skies. I collect data from the largest optical telescopes in the world to study the motions and chemistry of stars in galaxies and unravel the history of their formation. It was the harmony and beauty of physics and maths that I first fell in love with as a high school student. Physicists measure fundamental constants, derive physical laws from first principles and make solid predictions. Mathematics is the language and foundation of our understanding; it underpins the technological advances of our era. As a highly idealistic individual, I set out to solve the mysteries of the universe. I was enthralled by the possibility that the many unexplored secrets of deep space could hold the key to unlocking our understanding. After a BSc in physics and mathematics and an MSc in astrophysics from Bishop’s University (Quebec, Canada), I completed my PhD at Swinburne University (Melbourne, Australia) in 2011. I am currently an ARC Future Fellow, Scientia Associate Professor at the University of New South Wales. Who else am I? When I'm not busy resolving the mysteries of the universe, I enjoy spending time with my family, crochet, reading, traveling, clarinet, board games, camping and hiking. I am a Christian, neurodivergent and a diversity and inclusion advocate. Galaxy formation and evolution: Galaxy dynamics, Stellar populations and dynamics of extragalactic globular clusters, Discrete tracers of galaxy dynamics. Optical astronomy and telescope facilities: Observational techniques, Astronomical data reduction and analysis. Fields of Research (FoR): Cosmology and extragalactic astronomy. SEO tags: Expanding Knowledge in the Physical Sciences. My research interests have broadly focused on the formation and chemical enrichment of various structures in the universe. To this end, I have used a variety of techniques across a range of astronomical scales to better understand how the universe formed and how galaxies assembled. My research has led to the development of innovative techniques to exploit 3D spectroscopy data from the largest scales, cosmological voids, down to much smaller structures, globular clusters. While complex, the process of galaxy formation throughout cosmic time has led to recognisably distinct types of galaxy structures. I am currently using the MAGPI, Hector and SAMI survey data to understand the impact of various physical processes on the structural and dynamical evolution of galaxies. Current research focus: The spin of galaxies is slowing down and nobody really knows why. This dynamical transformation is predicted by theoretical simulations, but different simulations disagree on its exact causes and their relative importance. Until recently, the data required to map the gas and stars in galaxies during the transition and identify its root causes in galaxies around 3-4 billion years ago were critically lacking. My Future Fellowship project leverages on the Middle Age Galaxy Properties with Integral field spectroscopy (MAGPI) survey, a large programme on the European Southern Observatory's Very Large Telescope. This dataset is designed to directly detect and address this important unknown. By comparing MAGPI with local surveys (e.g. SAMI and Hector) and using redshift surveys such as GAMA and DEVILS, I am identifying the key physical drivers for the morphological and dynamical transformation of galaxies across cosmic time. Other research interests: My work on the assembly of the Umbrella Galaxy (see image above, Foster et al. 2014, MNRAS, 442, 3544) was the first to spectroscopically target bright tracers such as planetary nebulae, HII regions and globular clusters within the impossibly faint halo substructures in order to measure their kinematics. My research revealed the 3D structure of the shredded stars around NGC 4651. Combined with theoretical modeling, we were also able to identify the remnant nucleus of the infalling galaxy. My PhD research concentrated on globular clusters and the unresolved starlight around nearby early-type galaxies. I developed an innovative technique to measure the chemical content of unresolved globular clusters around nearby (within 60 Mpc) galaxies using the near-infrared calcium triplet (Foster et al. 2010, AJ, 139, 1566). Globular clusters come in two flavours: blue and red, for reasons that are subject to debate. We used data from the 10m Keck telescope on Mauna Kea in Hawaii to: (1) confirm that this `colour bimodality’ in globular clusters is related to a `metallicity bimodality’ (e.g. Foster et al. 2011, MNRAS, 415, 3393; Foster et al. 2010; Usher et al. 2015, MNRAS, 446, 369) and; (2) show that the blue and red globular clusters have distinct dynamics (e.g. Pota et al. 2013, MNRAS, 428, 389; Foster et al. 2011). These discoveries have led to new insights into and avenues for studying the total mass in galaxies (Cortesi et al. 2016, MNRAS, 457, 1242; Pota et al. 2015, MNRAS, 450, 3345), which is critical to our understanding of the distribution and amount of dark matter around galaxies. As a Masters student, I authored and developed an algorithm that identifies and quantifies the properties of cosmological voids in the universe (Foster & Nelson 2009, ApJ, 699, 1252). These regions devoid of visible matter are the largest structures observed in the universe. My void-finding algorithm has provided new constraints for cosmological models using data from the Sloan Digital Sky Survey (SDSS, Foster & Nelson 2009, Colberg et al. 2008, MNRAS, 387, 933) and is publicly available on this website.