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2/27/20: SO/NSF's OIR Lab Joint Colloquium Series: CANCELED Elisabeth Mills, University of Kansas


Title: Journey to the Center of the Galaxy: Following the Gas to Understand the Past and Future Activity of Galaxy Nuclei

Centers of galaxies are some of the most extreme objects in our universe: hosting starbursts and active supermassive black holes that can launch jets and winds far outside the compact galaxy nucleus. The effects of the unique interactions between stars, gas, and black holes that occur here don’t just stay confined to these small regions: they have an outsized influence on the overall evolution of galaxies as a whole. At just 8.1 kpc away, the center of the Milky way is unparalleled in its proximity, making it the best laboratory for detailed studies of the processes that govern and define galaxy nuclei. However, the Galactic center also presents a big challenge for these studies: it is a relatively quiet environment. Few stars are forming in this region, and the black hole is not active. Clearly, it hasn’t always been this way: from the Fermi Bubbles to hundred-year old echoes of X-ray bursts there are many relics of an active past in the center of our own Milky Way. We also know our Galaxy center likely won’t stay quiet for long: it contains a sizable reservoir of molecular gas that is the fuel for future star formation and black hole accretion. In this talk I will present the results of research following the gas and its properties from kiloparsec to sub-parsec scales to understand why the Galactic center is so quiet right now and what the future holds. Finally, I will discuss ongoing work to double and triple the sample size of galaxy nuclei with sub-parsec scale gas measurements, and what this means for putting the Galactic center in context with its more active neighbors.