Map of 621 GHz emission corresponding to dataset 2-H in Table A.1. The offsets from (RA[J2000], Dec[J2000]) are given in the upper left of each panel in seconds of arc. The horizontal and vertical axes bordering the entire set of 15 panels correspond roughly to these respective offsets for the positions at which the spectra shown in the individual panels were observed. The fine vertical scales on the individual panels, run from [− 0.2to2.5] degrees Kelvin; the width of the individual panels cover a V_lsr range of [− 60to80] km s^-1 roughly centred on the vertical line marking V_lsr = 12 km s^-1, the velocity of the narrow 621 GHz maser feature.