Centimeter continuum emission from NGC 7538IRS1. The left panel shows in color scale the new 1.2 cm continuum data imaged using only baselines between 10 and 37 km, achieving a spatial resolution of 0.06″ × 0.05″. The contours present for comparison the old VLA data from 1992 discussed previously in Gaume et al. (1995a), Sandell et al. (2009), Moscadelli & Goddi (2014), and Goddi et al. (2015) starting at the 4σ contour and continuing in 8σ intervals (1σ ~ 0.05 mJy beam^-1). The two stars indicate the CH₃OH maser positions by Moscadelli & Goddi (2014); see Sect. 3.1 for more details. The middle panel shows in color the spectral index map derived from the new full dataset with robust weighting −2 and the contours show the corresponding continuum image using all data at a resolution of 0.07″ × 0.05″. The contour levels start at a 4σ levels of 0.16 mJy beam^-1 and continue in coarser 32σ steps. The right panel again shows the new 0.06″ × 0.05″ data, now converted in the Rayleigh-Jeans approximation to brightness temperature.