Left panel: overlayed contours for dust continuum (gray, this work), and blue− and redshifted ¹³CO 2−1 outflow (blue and red, QZM11). Crosses mark the positions for dusty cores and red dots for IR sources. Right panel: schematic 3D cartoon of the proposed scenario for the NGC 7538 IRS 1−3 complex (Sect. 5.3). Yellow sphere represents MM1, blue and red cones represent the blue and red outflow lobes, and the gray structure represents the spiral arm. Faded colors represent the structures behind MM1 in the LOS direction.