a) Emission distribution of the HCO⁺J = 4−3 transition integrated between 37 and 40 km s^-1 (green contours) superimposed onto the H_α emission of the BRC. Contours levels go from 0.8 to 2.2 K km s^-1 in steps of 0.2 K kms^-1. b) Emission distribution of the CS J = 7−6 transition integrated between 37 and 40 km s^-1 (green contours) superimposed onto the H_α emission of the BRC. Contours levels are at 0.3, 0.4, 0.5, 0.6, and 0.7 K km s^-1.