a) Grand average of all CO (2–1) spectra, in T_mb vs. υ_LSR, of the 5′ × 5′ map toward α Centauri. Strong emission features at several lsr-velocities are evident in this direction of the Galaxy (ℓ^II = 31573, b^II = −068), with the strongest line at υ_LSR = −50 km s^-1. b) Integrated intensity map of the CO (2–1) line at υ_LSR = −50 km s^-1, i.e. ∫ T_-50 dυ, in the direction of α Centauri (for APEX and at ν = 230 GHz, ∫ T dυ (K km s^-1) = 6 × 10¹⁵ ∫ F_ν dν (erg cm^-2 s^-1)). The origin of the map is at the J2000 equatorial coordinates of α Cen B, i.e RA = 14^h39^m3506 and Dec = −60° 50′ 151, and read-out positions are marked by crosses. At the time of observation (16 August 2012), the star is located at the centre of the white ring. The bright feature south of the map centre is also prominent in the continuum observations longward of 100 μm (cf. Fig. 2) and is the dominating source at 870 μm (Fig. 5).