Line profiles of inversion transitions of ammonia from W33 A. These are shown on (Δα, Δδ) axes. The zero point is at the position of W33 A, R.A. : 18:14:39.10, DEC. : -17:52:03.0 (J2000). The X and Y axes indicate Right Ascension Offset (arcsec) and Declination Offset (arcsec), respectively. The main beam temperature scale for the NH₃ lines was obtained from continuum cross scans of 3C 286 (see Sect. 2). All radial velocities are on a V_LSR scale. At the assumed distance to the complex, ~2.4 kpc, 40′′ is equivalent to 0.5 pc. The individual spectra cover a velocity range of 32 to 38 km s⁻¹ and the ordinate provides main beam brightness temperatures in the range – 0.1 to 5.2 K (left panel), – 0.1 to 0.5 K (middle panel), and – 0.1 to 0.5 K (right panel).