WFC3/UVIS Photometric Transformations

We provide photometric transformation coefficients for converting magnitudes from the native WFC3/UVIS filter passbands to Johnson/Cousins UBVRI passbands in ABMAG, STMAG and VEGAMAG system. The transformation coefficients have been calculated both for UVIS1 and UVIS2 chips, for stars of various spectral types and a range blackbody temperatures using synthetic stellar/black-body models. We also provide a recipe which can be used to derive transformation coefficients using SYNPHOT. Our recommendation, however, is that the users should refer to WFC3 photometric results in a system based on the WFC3 filters themselves, and we warn that the transformations should be used with extreme caution since they can have limited precision.