Comparison of UV and the [C II] morphology obtained by simulating mock ALMA data for the galaxy image M1. Left panel: HST UV continuum data (background image) overlaid with the [C II] data obtained with natural weighting (contours). The cyan solid and dashed contours indicate respectively positive and negative levels of 3, 5, 7, 9 rms. The ALMA beam is reported as the cyan ellipse, while the HST PSF is reported as the white filled ellipse. Right panel: HST UV continuum data (background image) overlaid with the [C II] data obtained with robust weighting (contours). Contour levels are the same as in the left panel. Each stamp has a size of 3″ × 3″.