A HaloSat Analysis of the Eridanus X-ray Enhancement

HaloSat was a CubeSat operative between October 2018 and January 2021 with three collimated silicon drift detectors sensitive to X-rays in the energy range 0.4-7.0 keV. Its near 100 square degree field-of-view was ideal for resolving the energy spectra of large scale X-ray continuum emitters. The hot interior (~10⁶ K) of the nearby (~400 pc) Orion-Eridanus Superbubble is one such source of X-rays. We fit models of thermal plasma emission to several observation fields with combined coverage of the extent of the Eridanus X-ray Enhancement. Some fields required multiple plasma components of different temperatures to be well-fit, indicating interplay between physical processes. We present the physical interpretation of our results and accurate measurements of the Superbubble's interior temperature.