Astrophysics & Space Physics (301 VAN) – Chase Fuller; University of Iowa | Physics and

The Orion OB Association as a Generator for the Hot Circumgalactic Medium

Chase Fuller; University of Iowa

The Hot Circumgalactic Medium (CGM) surrounds galaxies. It is diffuse, X-ray emitting gas at temperatures in excess of a million Kelvin. It likely comes from both virialized material falling into the galaxies’ gravitational wells and by feedback from energetic processes from within the galaxy. OB associations, clusters of newly formed massive, hot stars, are a powerful feedback mode. In fact, the combination of their extreme stellar winds and localized Type-II supernovae sculpt so-called superbubbles out of the interstellar medium. Superbubbles are characterized by a dense supershell of swept up dust and neutral gas, and an interior filled with several million Kelvin gas. We used HaloSat, a CubeSat X-ray observatory built here at the University of Iowa, to observe the interior gas of the nearest superbubble to us: the Orion-Eridanus Superbubble (OES). We found that the properties of the interior gas are best explained by interpreting the Orion OB association as a generator that energizes the hot circumgalactic medium.