TAPIR Seminar

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https://caltech.zoom.us/j/92271559087?pwd=TFQ2YVk2N0FpSzhlR3JvZlFENTUyQT09

A detailed physical understanding of the high-energy interactions between black holes, stars, and neutron stars, combined with the context of their galactic birthplaces, will allow us to use these events as tools to better understand black holes at all masses, the lives and deaths of stars, and the dynamical mechanisms operating in galactic centers. I will start with tidal disruptions of stars by supermassive black holes. I will present the STARS library of interpolated tidal disruption event simulations and I will show that all of our simulations can be reduced to a single relationship that depends only on stellar structure. I will also present simulations of the chemical structure of a tidal disruption event disk—a key step in understanding the spectra of these events. Zooming in in scale to focus on interactions between stars and neutron stars, I will present the first 3D hydrodynamics simulations of common-envelope ejection and binary neutron star formation. The new theoretical framework developed with this work will allow for the modeling of virtually any binary star system. Finally, zooming out to connect these AU-scale phenomena to galaxy-scale physics, I will present a systematic study of tidal disruption event host galaxies in the context of galaxies in the local Universe, and in particular our finding that these galaxies are highly centrally concentrated. This galaxy-matching framework can be applied to any type of galaxy and we have recently applied it to changing-look AGN. I will also present a self-consistent physical model of the structure of AGN accretion disks with embedded stars, accounting for momentum and energy feedback from stars, supernovae, white dwarfs, neutron stars, and black holes.