A Spectral Study of the Soft X-Ray Background with the X-Ray Quantum Calorimeter
Abstract
High spectral resolution observations in the soft X-rays are necessary for understanding the hot-ionized component of the interstellar medium and its contribution to the Diffuse X-ray Background (DXRB). This extended source emission cannot be resolved with most wavelength dispersive spectrometers, making energy dispersive microcalorimeters (with 20-100x better spectral resolution than solid state detectors) the ideal choice for these observations. I present here a combined analysis of four sounding rocket observations of the DXRB, using the University of Wisconsin-Madison/Goddard Space Flight Center X-ray Quantum Calorimeter (XQC). XQC is a large area silicon thermistor microcalorimeter with energy resolution of 6-9 eV FWHM below 1 keV. The spectra support the existence of a ∼0.095 keV Local Hot Bubble and a ∼0.2 keV Hot Halo. At low galactic latitudes, an additional component of 3/4 keV emission can be consistently explained by unresolved dM stars. Discrepancies between repeated observations are compatible with expected contributions of time-variable emission from Solar Wind Charge Exchange (SWCX). Additionally, I present an algorithm for processing microcalorimeter data which was used for three of the sounding rocket flights. I demonstrate that this technique can significantly increase detector throughput without sacrificing energy resolution relative to conventional processing techniques. A considerable effort has been made to generalize the implementation of this algorithm in software, which makes it easily adaptable to other microcalorimter data sets.
- Publication:
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Ph.D. Thesis
- Pub Date:
- September 2018
- Bibcode:
- 2018PhDT........80W
- Keywords:
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- Astrophysics;Astronomy;Low temperature physics