Special Astrophysics Seminar

Resolving the Origins of the Soft X-ray Background:
A Spectral Approach

Dallas Wulf

University of Wisconsin

The Soft X-ray Background (SXRB) gives us an observational handle on hot, ionized gas in our Galaxy and the nearby Universe, and may hold the keys to answering important questions about feedback, metal transport, and the baryon budget. However, disentangling the multiple origins of the SXRB poses a significant challenge, pushing the limits of current instrument resolution, both spectral and spatial. I will present recent advancements made in the former, focusing on the University of Wisconsin-Madison/Goddard Space Flight Center X-ray Quantum Calorimeter (XQC), a soft X-ray microcalorimeter spectrometer. At energies below 1 keV, the SXRB is dominated by line emission from highly-charged ions. Energy-dispersive microcalorimeters like XQC offer the best option for resolving these lines, as the spectral resolution of ionization detectors is fundamentally limited and most wavelength-dispersive spectrometers are unable to resolve extended sources. Utilizing a combination of sounding rocket observations and laboratory measurements, this research aims to identify the spectral signatures of different emission mechanisms contributing to the SXRB, with the ultimate goal of better understanding its origins.