Integrated intensities (from left to right) of the HCO⁺, HNC 1–0 and HC₃N 10–9 line emission. The grayscale range is from 0 to 5.3, 0 to 3.3, and 0 to 1.0 Jy km s^-1 (beam)^-1 respectively. The contour levels are 0.26, 0.16, and 0.04 Jy km s^-1 (beam)^-1  ×  (1,3,5,7,9,11,13,15,17,19). (1′′ = 870 pc and and zero velocity was set to redshift z = 0.042170 for all lines). Cross refers to the center of the 85 GHz continuum. The maps are integrated over  ± 200 km s^-1 and exclude the line wings. Ellipse indicates beam size and orientation.