New Probes of Galactic Outflows at the Peak Epoch of Star Formation

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Galaxy formation is regulated by feedback in the form of large-scale outflows of gas. The details of this process are poorly understood as it is difficult to observe the faint emission from the gas. Principal Investigator (PI) Jones has identified a sample of gravitationally lensed galaxies, where a foreground galaxy bends the light from the distant galaxy and magnifies its weak emission. The PI will observe these lensed galaxies using the Keck Cosmic Web Imager (KCWI) instrument at the W. M. Keck Observatory to study how galactic outflows shaped their formation ten billion years ago. As part of this program the PI will teach scientific research methods to high school students in the California State Summer School for Mathematics and Science (COSMOS), with lectures on galaxies and cosmology, and an introduction to observational astronomy techniques using a rooftop telescope facility at the University of California - Davis campus. This proposal will support the analysis of data already in hand and additional observations of a larger sample. Integral field spectroscopy with the KCWI instrument will map the spatial extent and kinematics of outflowing gas using fluorescent emission lines, which will improve estimates of the mass loss rates. The same data also enable maps of the outflowing gas in absorption, which probes outflow energetics and launching sites as well as the chemical composition. The non-refractory element sulfur provides a measurement of total alpha-element metallicity relative to neutral hydrogen, while other elements such as silicon and nickel are sensitive to dust content and abundance patterns. Collectively these results will address the physical properties of galactic outflows and their role in regulating galaxy assembly at redshifts z=2-3.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.