Panoramic NIR surveys of the first generation of galaxies with Nancy Roman Space Telescope, Subaru/ULTIMATE and G-REX

Subaru/ULTIMATE, a future wide-field near-infrared imager with GLAO, can perform a sufficiently wide and deep K-band imaging survey in a part of the high latitude survey by NGRST in late 2020s. The K-band data will provide ~10/deg^2 z>12 objects, including non-zero z>14 objects, in an optimistic case. We recall that Subaru Telescope secured 100-nights of observing time for NGRST-Subaru 'synergistic' observations in the middle-late 2020s - supplying deep and wide K-band imaging data coordinated with NGRST deep fields can be an excellent use of this NGRST-Subaru synergistic program. We also have a plan of a new space-based wide-field imager focusing on the wavelengths longer than 2 micron, called G-REX, in 2030s. G-REX will detect many galaxies at z>15, dropping-out in NGRST filters.