James Webb Space Telescope Feed Post
Hidden giants in JWST's PEARLS: An ultra-massive z = 4.26 sub-millimeter galaxy that is invisible to HST
6" x 6" thumbnails of 850.1 and 850.2 showing the JWST F200W and F444W images along with the pixel-based MAGPHYS estimates of the log-scaled stellar mass and AV . The stellar-mass surface density is per 0."18x 0."18 pixel, corresponding to ~ 0.6 × 0.6 kpc in the source plane for 850.1 and ~ 0.5 × 0.5 kpc for 850.2. B1 was excluded from the map for 850.1 due to the poor quality of the SED fits at z = 4.26, supporting its likely lower redshift. B2 has much lower AV and stellar-mass surface density compared to the bulk of the massive and dusty remainder of 850.1. These very distinct properties motivate the decision to fit B2 and the bulk of 850.1 separately and then sum the results. In contrast, 850.2 exhibits a smaller variation in AV and stellar-mass surface density across the source.