Identifying XMM-Newton observations affected by solar wind charge exchange - Part I

TL;DR

This paper introduces a method to identify XMM-Newton observations affected by Solar Wind Charge Exchange (SWCX) emission by analyzing temporal variability in X-ray background, revealing previously unidentified SWCX cases and exploring their origins.

Contribution

The paper presents a novel variability-based technique to detect SWCX contamination in XMM-Newton data, enhancing the identification of such events and their potential sources.

Findings

Identified new cases of SWCX contamination in XMM-Newton data.

Correlated SWCX events with solar wind data from ACE.

Analyzed the geometry and viewing angles to determine emission origins.

Abstract

We describe a method for identifying XMM-Newton observations that have been affected by Solar Wind Charge Exchange (SWCX) emission and present preliminary results of previously unidentified cases of such emission within the XMM-Newton Science Archive. The method is based on detecting temporal variability in the diffuse X-ray background. We judge the variability of a low energy band, taken to represent the key indicators of charge exchange emission. We compare this to the variability of a continuum band, which is expected to be non-varying, even in the case when SWCX enhancement has occurred. We discuss previously published results with SWCX contamination that have been tested with the above method. We present a selection of observations that we consider to show previously unpublished SWCX enhancements, and further investigate these observations for correlation with data from the solar wind observatory, ACE. We also consider the geometry and viewing angle of XMM-Newton at the time of the observation to examine the origin of the charge exchange emission, whether it be from interactions with geocoronal neutrals in Earth's magnetosheath or from the heliosphere and heliopause.