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We present results from a sample of XMM-Newton and Suzaku observations of interstellar clouds that cast shadows in the soft X-ray background (SXRB) - the first uniform analysis of such a sample from these missions. By fitting to the on- and off-shadow spectra, we separated the foreground and Galactic halo components of the SXRB. We tested different foreground models - two solar wind charge exchange (SWCX) models and a Local Bubble (LB) model. We also examined different abundance tables. We found that Anders & Grevesse (1989) abundances, commonly used in previous SXRB studies, may result in overestimated foreground brightnesses and halo temperatures. We also found that assuming a single solar wind ionization temperature for a SWCX model can lead to unreliable results. We compared our measurements of the foreground emission with predictions of the SWCX emission from a smooth solar wind, finding only partial agreement. Using available observation-specific SWCX predictions and various plausible assumptions, we placed an upper limit on the LBs OVII intensity of ~0.8 photons/cm^2/s/sr (90% confidence). Comparing the halo results obtained with SWCX and LB foreground models implies that, if the foreground is dominated by SWCX and is brighter than ~1.5e-12 erg/cm^2/s/deg^2 (0.4-1.0 keV), then using an LB foreground model may bias the halo temperature upward and the 0.5-2.0 keV surface brightness downward by ~(0.2-0.3)e6 K and ~(1-2)e-12 erg/cm^2/s/deg^2, respectively. Similarly, comparing results from different observatories implies that there may be uncertainties in the halo temperature and surface brightness of up to ~0.2e6 K and ~25%, respectively, in addition to the statistical uncertainties. These uncertainties or biases may limit the ability of X-ray measurements to discriminate between Galactic halo models.
Observations of interstellar clouds that cast shadows in the soft X-ray background can be used to separate the background Galactic halo emission from the local emission due to solar wind charge exchange (SWCX) and/or the Local Bubble (LB). We present
We present measurements of the Galactic halos X-ray emission for 110 XMM-Newton sight lines, selected to minimize contamination from solar wind charge exchange emission. We detect emission from few million degree gas on ~4/5 of our sight lines. The t
The hot Local Bubble surrounding the solar neighborhood has been primarily studied through observations of its soft X-ray emission. The measurements were obtained by attributing all of the observed local soft X-rays to the bubble. However, mounting e
Aims. We study the soft X-ray emission induced by charge exchange (CX) collisions between solar-wind, highly charged ions and neutral atoms of the Martian exosphere. Methods. A 3D multi species hybrid simulation model with improved spatial resolution
It has been proposed that the charge exchange (CX) process at the interface between hot and cool interstellar gases could contribute significantly to the observed soft X-ray emission in star forming galaxies. We analyze the XMM-Newton/RGS spectrum of