In-orbit performance of the XMA for XRISM/Resolve

The in-orbit performance verification and calibration of the X-ray Mirror Assembly (XMA) on the XRISM satellite are ongoing. The optical performance of the XMA is being measured with bright point-like or bright small enough sources in orbit. This paper reports the preliminary results for the XMA of Resolve (Resolve- XMA). The in-orbit on-axis and off-axis (1.8′–9′ away from the aimpoint) Point Spread Function (PSF) of the Resolve-XMA were measured using 3C 273 and Cyg X-2, respectively. No significant changes were found in the PSF compared to on-ground results, indicating that the Resolve-XMA is functioning as expected (HPD ∼ 1.3′). For the Effective Area (EA) calibration, XRISM observed 3C 273 alongside other satellites. The Resolve spectrum of 3C 273 is well reproduced by an absorbed power law. While the best-fit photon index is consistent with that measured by NuSTAR, the flux is 5% higher than the NuSTAR measurement. In-orbit stray light observation was conducted with Crab at 60′ off from the aimpoint, and a signature of stray light on Resolve was detected. The observation of Resolve optical search has not yet been performed, and GX 3+1 has been proposed as the target.