Date:
Tue, 02/12/202512:30-13:30
Speaker: Manuel Behrendt (Racah Institute of Physics, HUJI)
Title: AVALON: Complete Multiphase ISM in Galaxy Simulations and Applications to Milky Way Structure
Abstract: I will present the AVALON simulation project, which achieves a complete multiphase interstellar medium in galaxy formation simulations, including the thermally unstable neutral medium (UNM)—a phase that has been challenging to capture in many galaxy simulations.Our approach combines two core elements: (1) an exact thermal integration scheme following Townsend (2009) that eliminates timestep-dependent discretization errors through piecewise integration of cooling and heating rates, and (2) cooling/heating physics calibrated to the photochemistry model of Kim et al. (2023), which reproduces realistic ISM equilibrium conditions.The simulations reveal that UNM maintains a quasi-stable gas mass fraction (~23%) in the full galaxy context. Individual local regions transition rapidly between stable phases while maintaining statistical equilibrium—previously achieved only in highly resolved local patch simulations. All phase properties (volume fractions, temperatures, densities, velocity dispersions) match Milky Way observations using straightforward thermal feedback.As an application of the AVALON simulation, I will present a new interpretation of the Milky Way's eROSITA X-ray bubbles: clustered supernova-driven galactic winds at 4–5 kpc from the Galactic Center can reproduce the observed morphology, angular extent (~80°), and X-ray flux with bubble heights of ~7 kpc—half the commonly assumed scale—without requiring recent AGN activity. I will conclude with my research plans at the Racah Institute on cosmic dawn galaxies and high-redshift galaxy formation.
Zoom: https://huji.zoom.us/j/84347178812?pwd=O5pq5eIDVgQe2PYjb1wWDAeChFbM3r.1
Meeting ID: 843 4717 8812
Passcode: 575367
Contact: Zhiyuan Yao
Title: AVALON: Complete Multiphase ISM in Galaxy Simulations and Applications to Milky Way Structure
Abstract: I will present the AVALON simulation project, which achieves a complete multiphase interstellar medium in galaxy formation simulations, including the thermally unstable neutral medium (UNM)—a phase that has been challenging to capture in many galaxy simulations.Our approach combines two core elements: (1) an exact thermal integration scheme following Townsend (2009) that eliminates timestep-dependent discretization errors through piecewise integration of cooling and heating rates, and (2) cooling/heating physics calibrated to the photochemistry model of Kim et al. (2023), which reproduces realistic ISM equilibrium conditions.The simulations reveal that UNM maintains a quasi-stable gas mass fraction (~23%) in the full galaxy context. Individual local regions transition rapidly between stable phases while maintaining statistical equilibrium—previously achieved only in highly resolved local patch simulations. All phase properties (volume fractions, temperatures, densities, velocity dispersions) match Milky Way observations using straightforward thermal feedback.As an application of the AVALON simulation, I will present a new interpretation of the Milky Way's eROSITA X-ray bubbles: clustered supernova-driven galactic winds at 4–5 kpc from the Galactic Center can reproduce the observed morphology, angular extent (~80°), and X-ray flux with bubble heights of ~7 kpc—half the commonly assumed scale—without requiring recent AGN activity. I will conclude with my research plans at the Racah Institute on cosmic dawn galaxies and high-redshift galaxy formation.
Zoom: https://huji.zoom.us/j/84347178812?pwd=O5pq5eIDVgQe2PYjb1wWDAeChFbM3r.1
Meeting ID: 843 4717 8812
Passcode: 575367
Contact: Zhiyuan Yao