Overview of the detected masers colored by velocity. The positional errors on the SiO and CH₃OH7₀−6₁⁺ measurements are much larger than for the other data sets because the measurements are low signal-to-noise from single-dish observations, yet they are still likely to be underestimated (see Sect. 3). The gray boxes show the pixel size from the Mopra observations of these lines. b) is a zoomed-in version of a) focusing on the interferometer observations. The large X marks the centroid location of the SMA-detected “core” (Walker et al., in prep.).