Growing in the Wind: Emission-Line Imaging of OVI in the Circumgalactic Medium

          @misc{ pirsa_PIRSA:25070039,
            doi = {10.48660/25070039},
            url = {https://pirsa.org/25070039},
            author = {},
            keywords = {},
            language = {en},
            title = {Growing in the Wind: Emission-Line Imaging of OVI in the Circumgalactic Medium},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {jul},
            note = {PIRSA:25070039 see, \url{https://pirsa.org}}
          }
          

Abstract

The baryon cycle of a galaxy involves a dynamic interplay between its star-forming disk and the environment of its virial halo, or circumgalatic medium. Simulations and observations agree that winds are a key seeding mechanism for the CGM, which serves as a reservoir for metals produced in disks. Cool clouds are predicted to form in the CGM from cooling halo gas, and are observed in absorbing sightlines to background quasars. This cloud growth may be accelerated by the action of winds. However, directly imaging the cold-hot interaction is extremely challenging, as most of the cooling channels lie in the UV and X-ray. I will present a deep image of OVI 1032, 1038 A and Lyman-alpha in the footprint of a prominent galactic wind. The OVI-emitting gas follows the morphology observed in lines at optical wavelengths. This represents only the second image of OVI in the halo or CGM of a galaxy, and is a signpost of cloud growth at large radii as the wind and CGM interact. This detection will help motivate further attempts to image the CGM-in-formation with existing or future facilities. It will also help inform models and simulations of the wind-CGM interaction.