Dr Caroline Foster : Why do galaxies slow down as they age?, Monday 2 September, 6:30pm

Presented at Sydney Observatory and on-line.

Comparing the rotation and random motions of stars and gas in galaxies at different epochs/redshifts, astronomers have known for some time that, on average and as a population, galaxies loose rotational support with time in favour of more chaotic random motions. There is a higher proportion of older galaxies that do not show evidence of rotation compared to younger galaxies and this proportion has evolved over time.

Is this because older galaxies were born out of more turbulent materials in the early universe to begin with (the “born-hot” scenario) or is this a result of a longer history of merging (the “latent heating” scenario)? Is this just a false dichotomy? What is the role of environment vs. conditions at birth in determining the dynamical state of galaxies today?

In my talk, I will discuss what is known about the dynamical evolution of galaxies and discuss my own foray into trying to answer these questions and understand the physical drivers of the dynamical transformation of galaxies through cosmic time.

Bio

Dr Foster is an astronomer within the School of Physics at the University of New South Wales. She is originally from Quebec, Canada where she completed a BSc in physics and mathematics and an MSc in astrophysics. Caroline completed her PhD at Swinburne University (Melbourne, Australia) in 2011.

Dr Foster is currently an ARC Future Fellow and Scientia Senior Lecturer at UNSW. Her research interests have broadly focused on the formation and chemical enrichment of various structures in the universe. Her 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.

Dr Foster is a fierce diversity advocate and a keen outreach/public speaker/author.

Details: This presentation will be in person at Sydney Observatory and also by Zoom. Members are encouraged to attend on-site. All members will also be emailed the Zoom link. If you are not a member and want to attend this talk please email our secretary on: sydneycityskywatchers@gmail.com.

Prior to the keynote which commences at 6:50pm there are short presentations by members.