Abstract

The X-Ray Imaging and Spectroscopy Mission (XRISM) is an international X-ray observatory developed by Japan Aerospace Exploration Agency (JAXA) and National Aeronautics and Space Administration (NASA) in collaboration with European Space Agency (ESA), successfully launched in September 2023. Since the early stage of the project, the XRISM science operations team (SOT) was organized independently of the spacecraft bus system and mission instrument development teams, having prepared for the in-orbit science operations to maximize the scientific outputs. During about half year for the initial operation phase after launch, operations for the mission instruments were started, and the quick-look and the pipeline processes were carried out by SOT in order to check the functions of the instruments. After transition to the nominal operation phase, we started the target observations in the performance verification phase, whose short and long-term observation plans are considered by SOT, including planning the target of opportunity observations. The information on the observation modes of the mission instruments and the status of the data processing is maintained collectively in database synchronized between JAXA and NASA. We also performed the performance verification and optimization activities which provide the well-calibrated data, appropriate tools, and analysis methods for the users and established a help desk that supports the XRISM data analysis. The publicly solicited observation for the guest observer will be started from August or September 2024. These daily science operations are being carried out by dedicated scientists belonging to JAXA in collaboration with the other SOT members, the mission operations team and the instrument teams. This paper will introduce the ground system for the XRISM science operations and report on the activities of the SOT from the launch to today and plans for future science operations.