CAREER: The Disk/Halo Link: Synthesizing Gaseous Tracer Samples in the Milky Way

University Of Washington, Seattle WA

Investigators

Abstract

The Milky Way’s gaseous circumgalactic medium is a fossil record of the formation of our Galaxy and a large reservoir of material for future star formation. Only 5% of the volume of this gaseous halo is currently mapped. Dr. Werk and her team will map the full extent of the warm ionized halo gas. The observations will further our understanding of the chemical composition and flow of gas in the halo. Dr. Werk will expand her successful community college transfer program at Seattle Central College to include five additional colleges across Washington State. The transfer program provides mentorship for students as they successfully transition to a 4-year STEM program at the University of Washington. In addition, the program provides full programmatic support to astronomy undergraduates with student-focused research opportunities and learning initiatives. Dr. Werk and her team will map the full extent of the warm ionized halo gas using observations of halo stars, distant quasi-stellar objects (QSOs), pulsars, and fast radio bursts (FRBs). The metallicity of the ionized CGM will be measured using 40 lines of sight towards UV-bright stars in the Galactic halo that lie within close proximity to a known pulsar. The low velocity, ionized, extended MWCGM (Milky Way gaseous circumgalactic medium) will be characterized by subtracting measurements of unsaturated Si IV and C IV absorption profiles toward halo blue horizontal branch stars from the same measurements toward distant QSOs nearby in projection. A line profile analysis will quantify the contribution of non-thermal processes to the MWCGM energetics. Approximately 150 pairs of QSOs and stars will be analyzed including new UV-bright QSO targets at low Galactic latitudes. 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.