SIXTE simulations of the center of Tycho’s SNR based on the parameter mapping presented in this study. Left panel: flux image of Tycho’s SNR as observed by Chandra, corrected by the exposure map. We overlay the fields of view of the instruments XRISM/Resolve and Athena/X-IFU. Right upper panel: corresponding SIXTE image and spectrum simulation with XRISM/Resolve for 150 ks and the gate valve closed. The spectrum in blue is extracted from a region of 4×4 Resolve pixels (large green square in the XRISM image). Right lower panel: SIXTE image and spectrum simulation with Athena/X-IFU for 50 ks. The spectrum in blue is extracted from a 4×4 X-IFU pixels region (small green square in the Athena image). The XRISM/Resolve and Athena/X-IFU spectra have an adaptive rebinning to have at least 5 photons in each energy bin. We compare them with Chandra spectra (observations of 2009, 734 ks in total) extracted from the respective green regions.