Abstract
Speaker: Andrew Fox
Title: Highly Ionized Plasma in High-Velocity Clouds
Abstract: Over the last 15 years a new window on the physics and structure of high-velocity clouds (HVCs) has been opened through UV absorption-line studies. Large samples of high-resolution FUSE and HST quasar spectra have been surveyed for HVC absorption in the ions OVI, CIII, and SiIII. These ions are detected in the large, 21-cm-emitting clouds (Complex C, Magellanic Stream) as well as in mysterious “highly ionized HVCs” with no 21-cm counterparts. I will review these surveys, mentioning their implications for the surrounding hot Galactic corona and for the global process of Galactic accretion. Finally I will highlight open questions, including the relationship between the high-ion-absorbing plasma and the Hα-emitting plasma.