Maps of NH₃ kinetic temperature in units of Kelvin (left), the logarithm of the total-NH₃ column density in units of cm⁻² (middle), and the corresponding logarithm of the fractional abundance (right). The reference position is l = 28.59°, b = 3.55°. Contours of integrated NH₃ (1,1) intensity are the same as in Fig. 4 and cover the velocity range 4 < V_LSR < 10 km s⁻¹. Contours start at 0.23 K km s⁻¹ (5σ) on a main beam brightness temperature scale and go up in steps of 0.23 K km s⁻¹. Magenta stars show the locations of the OB association (OS1a, IRS1, IRS1a, IRS2, IRS2a, IRS2b, IRS3, and IRS3a) in W 40.