A High Spectral Resolution Study of the Soft X-ray Background with the X-ray Quantum Calorimeter

TL;DR

This study uses high spectral resolution X-ray observations to analyze the diffuse X-ray background, identifying contributions from local hot gas, the galactic halo, and unresolved stars, while considering solar wind effects.

Contribution

First high spectral resolution analysis combining multiple observations of the diffuse X-ray background with detailed component identification.

Findings

Detection of a ~0.1 keV Local Hot Bubble.

Identification of a ~0.2 keV Hot Halo.

Observation of a ~0.9 keV component at low galactic latitudes explained by unresolved dM stars.

Abstract

We present here a combined analysis of four high spectral resolution observations of the Diffuse X-ray Background (DXRB), made using the University of Wisconsin-Madison/Goddard Space Flight Center X-ray Quantum Calorimeter (XQC) sounding rocket payload. The observed spectra support the existence of a $\sim0.1~$keV Local Hot Bubble and a $\sim0.2~$keV Hot Halo, with discrepancies between repeated observations compatible with expected contributions of time-variable emission from Solar Wind Charge Exchange (SWCX). An additional component of $\sim0.9~$keV emission observed only at low galactic latitudes can be consistently explained by unresolved dM stars.