A diagnostic to trace shocked ejecta in SN 1987A using XRISM - Resolve

Supernova (SN) 1987A is one of the best candidates to exploit the capabilities of the upcoming XRISM satellite, offering the unique opportunity to observe the rapid evolution of the non-equilibrium ionisation (NEI) plasma in a very early stagesupernova remnant. Recent studies provide compelling evidence that in the forthcoming years, the X-ray emission from SN 1987A will increasingly stem from the ejecta. Our aim is to assess the proficiency of XRISM-Resolve high resolution spectrometer in pinpointing signatures of the shocked ejecta in SN 1987A. Taking advantage of a self consistent state-of-art magneto-hydrodynamic simulation, we synthesized the XRISM-Resolve spectrum, simulating the allocated observation during the performance verification (PV) phase, which is expected to occur in 2024. Our forecast suggests that the bulk motion Doppler broadening from the fast moving ejecta will dominate over thermal broadening in all the visible ion emission lines. Therefore we can strongly link the broadened line emission to the freshly shocked ejecta, using it as a diagnostic tool to retrieve the ejecta dynamics from the X-ray emission.