Astrophysics Seminar: Prof. Sean Johnson, University of Michigan


Location: 184 Nieuwland Science Hall (View on map )

Directly tracing the CGM gas flows that govern galaxy evolution using non-resonant optical emission lines

Prof. Sean Johnson
Department of Astronomy
University of Michigan

The circum-galactic medium (CGM) is at the nexus of the gas inflows and outflows that regulate galaxy evolution. Consequently, the CGM provides an ideal laboratory for studying galaxy fueling, feedback, and interactions. Historically, studies of the CGM primarily relied on background absorption spectroscopy which provides a uniquely sensitive probe of intervening gas but lacks the spatial information needed to differentiate the origins of CGM gas flows unambiguously. Recently, the advent of wide-field optical integral field spectrographs enabled the discovery of giant (>50 kpc) scale CGM nebulae around quasars in non-resonant, rest-optical emission lines, providing unique 3D (2 spatial + velocity) maps of the CGM. In this talk, I will present results from recent and ongoing surveys that enable simultaneous observations of the CGM in absorption around foreground galaxies and emission studies of the CGM around quasar hosts at z<1. I will focus on a newly discovered system that enables us to trace cool accretion over 100 kpc from halo scales and into the ISM of a quasar host. Finally, I will conclude with a summary of future prospects, including upcoming instrumentation on Magellan and the European Extremely Large Telescope.

Hosted by Prof. Lehner

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