Black line: intensity of the ¹²CO(2−1) line integrated between LSR velocities −25.5 and −27.5 km s^-1 observed along an EW strip at the declination of the star (Δδ = 0′′). Red line: the response of the telescope error beam to the ¹²CO(2−1) emission along the same strip. The error beam consists of 3 Gaussians of full width at half power (FWHP) 65′′, 250′′, and 860′′ and intensities 1.9 × 10^-3, 3.5 × 10^-4, and 2.2 × 10^-5 relative to the main beam, respectively. Blue line: the ¹²CO(2−1) line intensity after removal of the error beam response.