Peak flux densities vs peak velocities of the Gaussian components fitted to the H₂O maser features detected in epochs 1998.40 (red triangles) and 2017.45 (black squares). The segments represent the Δv_L of the Gaussian components. The dashed and dotted lines indicate the mean velocities of the north (TXS.B03 and TXS.V04–V05) and the central (TXS.B01 and TXS.V01–V03) groups of the H₂O maser features, respectively, at the two different epochs. The two components (3 and 4) of TXS.B02 are considered part of the intermediate gas between the two groups, and therefore have been separated for the calculation of the mean velocities. The numbers correspond to the fitted Gaussian components, as reported in Tables 2 and 3 (see Sect. 5.1 for more details).