NIR Filter Transformations Across the HR Diagram: JWST, Roman, and Euclid

Abstract We present new color transformations between select near-infrared filters on JWST/NIRCam, Euclid/NISP, Roman/WFI, HST, and ground-based izY + IJHK S , for a total of 105 unique filter combinations. Additionally, we apply these transformations to predict the color–magnitude relation of the tip of the red giant branch as seen with JWST, Euclid, and Roman based on theoretical results for Hubble Space Telescope and Two Micron All Sky Survey filters; for JWST we find good agreement with empirical results in the literature. We also find typical residual dispersion around these transformations of 0.01 mag for Cepheid and RR Lyrae variables and RGB stars, but up to 0.1 mag for O- and C-rich TP-AGB stars.