The XRISM Resolve High-Resolution X-Ray Spectrometer

The X-Ray Imaging and Spectroscopy Mission (XRISM) is an international collaboration led by JAXA with major participation and contributions from NASA and ESA to deploy an advanced X-ray observatory. It is designed to address some of the most timely questions in present-day astrophysics. It was successfully launched from Tanegashima, Japan on September 7, 2023. XRISM has two focal plane instruments, the Xtend X-ray camera with a relatively large field of view of 38 arcminutes and moderate spectral resolution, and the Resolve high-resolution X-ray spectrometer, with a 3 arcminute field of view but 5 eV spectral resolution over a large portion of the X-ray energy band. The observatory has been commissioned and has begun calibration and performance/verification observations of celestial sources. Resolve is a pioneering instrument, with a unique capability to provide high spectral resolution of extended sources and provide the highest resolving power of any astronomical spectrometer above ~ 1 keV. This makes it the instrument of choice for many celestial objects, including supernova remnants, galaxies and clusters of galaxies, and other sources that have strong emission lines associated with Fe that can yield sensitive diagnostic information, including velocity measurements. In this talk we will describe the Resolve instrument, how it works, what it can do, and give an overview of some of the observations and results that are likely to come from the XRISM observatory.