Astrophysics Brown Bag Lunch Talk 2/7/2022: Speakers: Ben Keller (Heidelberg University) And Roan Haggar (University Of Nottingham)

Monday February 7, 2022 12:00 pm
via Zoom

Monday, February 7, 2022

12:00 – 12:30pm
Ben Keller, Heidelberg University
Stellar feedback in galaxies: from the dense interstellar medium to circumgalactic gas

Abstract: Galaxies like our own, with halo masses ~1012 Msun, live in an interesting part of parameter space. Not only are they the “turnover” in the galaxy mass Schecter function, they also have the highest stellar mass (and baryon) fraction, very low bulge-to-disk ratios, and dominate the star formation of the epoch they live in.  Historically, simulations of these galaxies have struggled to regulate the total stellar mass of the galaxy and produce disc-dominated systems.  More recently, tensions have been identified between observations of the diffuse stellar halo and those seen in simulations.  All of these effects are deeply tied to how the formation of massive stars inject energy and momentum into the galaxies which they are born in. Modelling this physics is challenging, as it involves many decades in scale across space and time, with many physical processes in play.  In this talk, I will present results from a handful of recent papers that examines how we might model these processes, and how observational measurements can help us constrain our theories of how energy released by stars shapes the assembly of galaxies, their ISM, and the hot, diffuse CGM that surrounds them.

Bio: I am a postdoctoral researcher in the MUSTANG group at Universität Heidelberg’s Astronomisches Rechen-Institut. I obtained my PhD at McMaster University in 2017, after a BSc in Physics with a minor in Computer Science from the University of Calgary.  My research has been broadly focused on feedback processes in galaxies, studied through numerical simulations.  I’ve also worked on studies examining the formation and evolution of globular clusters, the demographics of planetary systems, polarized emission from radio galaxies, and cosmology.  In the last few years, I’ve also gotten in to woodworking and furniture making :).



12:30 – 1:00

Roan Haggar, University of Nottingham

Backsplash galaxies and galaxy groups in the outskirts of clusters

Abstract: The cosmic environment of a galaxy strongly affects its evolution. For example, galaxies within a galaxy cluster are heavily influenced by this environment, but can also be impacted by “pre-processing”, which includes the environments that they have previous passed through, such as galaxy groups. Using hydrodynamical simulations of galaxy clusters, we investigate galaxies with different environmental histories, such as “backsplash galaxies” and galaxies that have been accreted as members of groups. We quantify the prevalence of these different galaxy classes, how their prevalence depends on cluster properties, and how we can use simulations to better inform future observational studies of cosmic environment.

Bio: I’m in the final year of my PhD at the University of Nottingham, where my research focuses on galaxy evolution, galaxy clusters, and investigating how simulations can aid observational studies. Most of my work is based around using hydrodynamical simulations, and I am currently in the process of searching for postdoctoral positions that would allow me to continue working in this area.


Event Contact

Josh Borrow