Spitzer false-colour image using 3.6, 4.5, and 8 μm, as blue, green, and red, respectively (Stolovy et al. 2006). The white boxes indicate the position of Sgr C and Sgr B1, as well as the control field and the central NSD region. The black shaded area shows an avoided region in the analysis of the central NSD region in Nogueras-Lara et al. (2020a), corresponding to the nuclear star cluster. The small dashed rectangles indicate regions of particular interest within the Sgr C and Sgr B1 fields. The zoomed-in image corresponds to a GALACTICNUCLEUS JHK_s false-colour image of the Sgr C field (see Sect. 4.1 for details). The white circles correspond to two WCL stars (Clark et al. 2021) and the dotted ellipse outlines a region where H₂CO and CH₃OH masers have been identified (Caswell 1996; Lu et al. 2019a). The compass indicates Galactic coordinates.