JVLA 1.6 cm continuum map of Sgr B2(N), shown by the gray shaded areas and black contours with levels of 5, 10, 30, and 50 × 0.2 mJy beam⁻¹. The reference position is , and , the peak position of the continuum source K2. The crosses, thin diamonds, diamonds, stars, and circles show the positions of NH₃ (6,3), (7,4), (8,5), (9,6), and (10,7) emissions. H₂O (McGrath et al. 2004), class II CH₃OH (Caswell 1996; Lu et al. 2019), H₂CO (Mehringer et al. 1994; Hoffman et al. 2007; Lu et al. 2019), and OH (Gaume & Claussen 1990) masers are presented as triangles, squares, pentagons, and hexagons, respectively. The color bar indicates the velocity range (V_LSR) of maser spots. Red crosses mark the positions of the hot cores Sgr B2(N1), N2, and N3, taken from the 3 mm imaging line survey “Exploring Molecular Complexity with ALMA” (EMoCA, Bonfand et al. 2017). The systemic velocities of the hot cores N1, N2, and N3 are V_LSR = 64 km s⁻¹, V_LSR = 74 km s⁻¹ and V_LSR = 74 km s⁻¹, respectively (Bonfand et al. 2017).