This week's PhD colloquia are highlighted.
| Date | Time | Title/Abstract | Speaker | Affil. |
|---|---|---|---|---|
| 15/01 Wednesday BW.0.32 | 14:15 | Big simulations for big problems In this colloquium I investigate cosmology and the large scale structure of the Universe using cosmological simulations. The fields of cosmology, numerical cosmology, structure formation and galaxy clusters are introduced. Then I discus a machine learning method to set up subgrid models in numerical simulations, which I use to set up the FLAMINGO simulation suite. With this method I can calibrate our models directly to the observational data, without the needed of running thousands of hydrodynamical simulations. I then investigate selection effects on galaxy clusters and their impact on cosmology. Finding that for upcoming surveys the careful modeling of your selection effects is very important, and current models do not have the degree of accuracy required to make clear statements about the inferred cosmology. In the final part I will investigate the large scale flows of the universe, and their origin. I find that the mass contained in filaments is the main driver of cosmic dynamics. However for the smaller scale structures, voids also provide an important contribution. | Roi Kugel | Leiden Observatory |
| 05/02 Wednesday BW.0.32 | 14:15 | Gas physics in simulated galaxy clusters Galaxy clusters are the behemoths sitting at the nodes of the cosmic web. They are powerful tracers of the evolution of the Universe, and are often assumed to be simple, well-behaved systems. In this talk I will focus on the gas physics within the clusters, which I probe using both idealized simulations, and the new FLAMINGO simulations. I will show how the choice of hydrodynamic solver influences the survival of cold clouds entrained within a hot wind, a scenario commonly encountered on scales ranging from the ISM to the IGM. Following those idealized simulations, I will introduce FLAMINGO and results to prove that the galaxy groups and clusters reproduce observations. Obtaining accurate masses for these massive haloes is extremely challenging observationally, and in the remainder of the talk I will show where biases in the mass estimate originate, and what we can learn from correlated scatter between different observables from the same object. | Joey Braspenning | Leiden Observatory |
| 03/03 Monday BW.0.32 | 15:15 | The Evolutionary Tale of Gaseous Exoplanets The evolution and fate of gaseous exoplanets are continuously shaped by stellar activity across both short and long timescales. Short-term events, such as stellar flares, produce intense bursts of high-energy radiation that break apart molecules in the upper atmosphere of the exoplanet, driving significant chemical changes. Over longer periods, prolonged exposure to strong stellar irradiation gradually heats the planet, leading to atmospheric escape and potential transformation in its structure and composition. To better understand these processes, we employ (photo)chemical disequilibrium modelling, radiative transfer simulations, and planetary evolution codes to analyse the interiors and atmospheres of gaseous exoplanets. By doing so, we aim to determine how these external influences shape their composition, structure, and observable characteristics, shedding light on their long-term atmospheric evolution. Depending on the type of planet, star, and chemistry considered, these impacts can alter exoplanetary atmospheres significantly over both short- and long timescales. | Amy Louca | Leiden Observatory |
| 22/04 BW.0.31 | TBA TBA | Claudia Giese | Leiden Observatory | |
| 29/04 BW0.32 | TBA TBA | Joshua Butterworth |
For questions and/or suggestions concerning the colloquium series. Please contact Andrew Sellek (e-mail ).