Radial distribution of the observed SiO(5–4)/SiO(6–5) intensity ratio (left). The band between 0.5 and 0.6 shows the prediction of a simple LTE model. The red line shows the value measured by ALMA/ACA. The blue curve uses the 2023 A-configuration observations, which suffer from a small maximal recoverable scale. The B- and A+B-configuration histograms, shown in magenta and black respectively, combine 2023 and 2024 observations and therefore suffer from a possible variability between the two years. Centre and right panels show the Doppler velocity spectra measured using ALMA/ACA compared with the present NOEMA observations integrated over R<1.5 arcsec.