Dissecting the High Energy Plasma Environment of Sagittarius A

The crowded central parsecs of our Galaxy offer a unique environment to study accretion physics, plasma dynamics, star formation, and more. Within arcseconds of central supermassive black hole Sagittarius A (Sgr A), colliding stellar winds from Wolf-Rayet stars in the nuclear star cluster generate a hot plasma reservoir from which Sgr A accretes. Given this abundance of accretion material, the SMBH radiates at a lower luminosity than expected. At larger angular scales, the extended Sgr A plasma environment overlaps in our line of sight with the supernova remnant Sgr A East. Through Chandra spectroscopy and imaging, I examine the extended X-ray plasma at multiple scales. To investigate the spectrum of the accretion flow, I perform forward-modeling of High Energy Transmission Grating-Spectrometer (HETG-S) data, accounting for the accretion geometry and instrumental effects. We found that a Radiatively Inefficient Accretion Flow (RIAF) model fit to the quiescent HETG-S spectrum indicates an outflow balancing inflowing material and a sub-solar iron abundance. Synthetic spectra from smoothed particle hydrodynamic simulations of the stellar‐wind plasma fit equally well, but the two scenarios will only be distinguishable with future microcalorimeters that have high spatial resolution. Lastly, I use data-driven signal separation techniques to analyze Chandra imaging data of the extended emission around Sgr A . In particular, the supernova remnant Sgr A East may yield insight into the recent history of star formation, dust physics, and feedback in the Galactic Center. In this work, I separate Sgr A East from the cooler plasma around Sgr A. Through comparison with a wide range of multiwavelength datasets, we assess the spatial and spectral relationships among the observed structures and discuss the physical implications.