On the nature of highly ionized gas in the circumgalactic environment of galaxies

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A thorough understanding of the distribution and physical nature of highly-ionized gas in the outer regions of galaxies is of crucial importance to characterize the matter exchange between the interstellar gas in galaxies and the intergalactic medium. In this project, we will use high-resolution smoothed particle hydrodynamic (SPH) cosmological simulations from the so-called OverWhelmingly Large Simulations (OWLS) project to study the properties of highly-ionized gas in the circumgalactic environment of low-redshift galaxies. We will generate synthetic absorption spectra of high ions such as OVI, Ne VIII, and others along sightlines passing through the large-scale environment of galaxies and study the absorption characteristics, filling factors, and physical conditions in the circumgalactic gas component. The statistical properties of the synthetic spectra then will be compared to quasar absorption-line data of low-redshift OVI absorbers from FUSE and HST. Our project is aiming at a better understanding of the physical nature of the highly-ionized gaseous envelopes of galaxies and their connection to the multi-phase, multi-scale interstellar medium and the cosmic web.