Determination of the Solar System contribution to the soft x-ray sky
Summary
Solar wind charged particles interact with diffuse gas within the heliosphere, producing soft x-rays. This solar wind charge exchange (SWCX) process produces foreground emission that complicates interpretation of x-ray observations. In this work, we analyze x-ray observations of the western Galactic hemisphere by the Extended Roentgen Survey with an Imaging Telescope Array (eROSITA) instrument on the Spectrum-Roentgen-Gamma (SRG) spacecraft. These data avoid contamination by Earth's geocor
Content
# Determination of the Solar System contribution to the soft x-ray sky
*Published: 2026 Apr 16*
Solar wind charged particles interact with diffuse gas within the heliosphere,
producing soft x-rays. This solar wind charge exchange (SWCX) process produces
foreground emission that complicates interpretation of x-ray observations. In
this work, we analyze x-ray observations of the western Galactic hemisphere by
the Extended Roentgen Survey with an Imaging Telescope Array (eROSITA)
instrument on the Spectrum-Roentgen-Gamma (SRG) spacecraft. These data avoid
contamination by Earth's geocorona and are derived from four surveys of the full
sky, including during the minimum of the Sun's activity cycle. We determine the
SWCX contribution and subtract it from the survey, providing a less contaminated
view of the diffuse soft x-ray sky. We also demonstrate that x-rays can be used
to map the flow of interstellar matter through the Solar System.
DOI: 10.1126/science.adt9147