Multiphase Gas in Elliptical Galaxies

Yuan Li (Berkeley) - September 10, 2018 at 12:10 pm

Abstract: Recent observations have found extended multiphase gas in a significant fraction of cool-core galaxy clusters and massive elliptical galaxies. In this talk, I will discuss the development of thermal instability and formation of multiphase structures in these massive systems. Using high-resolution 3D simulations of idealized galaxy clusters and elliptical galaxies, I study the interplay between radiative cooling, momentum-driven AGN feedback, star formation, and stellar feedback. In some elliptical galaxies, the entropy of the hot halo gas rises sharply as a function of radius. The hot halo is thermally stable and run-away cooling can only happen in the very center of the galaxy. In other elliptical galaxies and the center of cool-core galaxy clusters, the hot halo gas has a cooling to free-fall time ratio close to 10, and the non-linear perturbation driven by AGN feedback can cause the hot gas to frequently precipitate into extended multiphase filaments. In addition, the uneven heating from Type Ia Supernovae and the winds from AGB stars can also produce multiphase gas in massive galaxies, and these processes cannot be resolved in current cosmological simulations.

The seminar will be held in 131A Campbell Hall.

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