\begin{table}%t3 \caption{\label{met_tab}\label{tab3}Parameters of EVN 6.7~GHz methanol maser features.} \small%\centering \par \begin{tabular}{ccrrcrrcrrr} \hline \hline\noalign{\smallskip} Feature & $V_{\rm LSR}$ & \multicolumn{1}{c}{$F_{\rm peak}$} & Var.\tablefootmark{a} & & \multicolumn{1}{c}{$\Delta x$} & \multicolumn{1}{c}{$\Delta y$} & & \multicolumn{1}{c}{$V_{x}$} & \multicolumn{1}{c}{$V_{y}$} & \multicolumn{1}{c}{$\Delta|V|/|V| $} \\ & (km s$^{-1}$) & \multicolumn{1}{c}{(Jy beam$^{-1}$)} & & & \multicolumn{1}{c}{(mas)} & \multicolumn{1}{c}{(mas)} & & \multicolumn{1}{c}{(km s$^{-1}$)} & \multicolumn{1}{c}{(km s$^{-1}$)} & \\ \hline \par 1 & 62.11 & 20.62 & 20\% & & $ -106.27\pm0.09 $ & $ 205.81\pm0.13 $ & & ... & ... & ... \\ 2 & 59.47 & 12.90 & 8\% & & $ 0 $ & $ 0 $ & & $ -3.2 \pm 1.0 $ & $ -4.0 \pm 1.4 $ & 25\% \\ 3 & 64.13 & 7.88 & 20\% & & $ -72.93\pm0.09 $ & $ 175.07\pm0.13 $ & & ... & ... & ... \\ 4 & 58.42 & 7.60 & 3\% & & $ 40.35\pm0.09 $ & $ -18.67\pm0.13 $ & & $ -1.7 \pm 1.0 $ & $ -6.1 \pm 1.4 $ & 22\% \\ 5 & 63.78 & 7.15 & 35\% & & $ -158.52\pm0.09 $ & $ 135.34\pm0.13 $ & & $ -0.6 \pm 1.0 $ & $ -3.5 \pm 1.4 $ & 40\% \\ 6 & 66.06 & 4.15 & 9\% & & $ -206.96\pm0.09 $ & $ 113.62\pm0.13 $ & & $ 1.8 \pm 1.1 $ & $ 11.0 \pm 1.5 $ & 14\% \\ 7 & 67.81 & 2.98 & 18\% & & $ -200.44\pm0.08 $ & $ 120.97\pm0.12 $ & & $ 0.7 \pm 1.0 $ & $ 4.1 \pm 1.4 $ & 35\% \\ 8 & 68.52 & 2.42 & 18\% & & $ -198.32\pm0.10 $ & $ 120.56\pm0.14 $ & & $ 5.4 \pm 1.2 $ & $ 3.3 \pm 1.7 $ & 22\% \\ 9 & 63.95 & 2.03 & 17\% & & $ -58.07\pm0.10 $ & $ 177.76\pm0.17 $ & & ... & ... & ... \\ 10 & 59.91 & 1.77 & 45\% & & $ 37.02\pm0.10 $ & $ 3.00\pm0.15 $ & & $ -4.2 \pm 1.2 $ & $ -6.1 \pm 1.8 $ & 22\% \\ 11 & 64.74 & 1.60 & 32\% & & $ -212.91\pm0.10 $ & $ 125.86\pm0.16 $ & & ... & ... & ... \\ 12 & 57.02 & 1.20 & 21\% & & $ 44.19\pm0.09 $ & $ -24.65\pm0.16 $ & & $ -1.3 \pm 1.2 $ & $ -4.6 \pm 2.0 $ & 41\% \\ 13 & 58.42 & 1.16 & 8\% & & $ 20.18\pm0.18 $ & $ -18.57\pm0.46 $ & & ... & ... & ... \\ 14 & 64.30 & 1.13 & 30\% & & $ -85.95\pm0.10 $ & $ 168.74\pm0.17 $ & & ... & ... & ... \\ 15 & 57.45 & 0.99 & 10\% & & $ -100.07\pm0.10 $ & $ -52.87\pm0.16 $ & & ... & ... & ... \\ 16 & 56.84 & 0.87 & 2\% & & $ -82.83\pm0.11 $ & $ -55.85\pm0.18 $ & & $ -6.3 \pm 1.6 $ & $ -2.4 \pm 2.6 $ & 27\% \\ 17 & 62.55 & 0.72 & 44\% & & $ -210.41\pm0.13 $ & $ 101.17\pm0.27 $ & & ... & ... & ... \\ 18 & 58.51 & 0.56 &... & & $ -15.95\pm0.22 $ & $ 0.44\pm0.33 $ & & ... & ... & ... \\ 19 & 58.60 & 0.49 &... & & $ 69.45\pm0.19 $ & $ -77.32\pm0.31 $ & & ... & ... & ... \\ 20 & 61.84 & 0.41 & 25\% & & $ -102.92\pm0.15 $ & $ 189.05\pm0.30 $ & & ... & ... & ... \\ 21 & 61.76 & 0.40 & 45\% & & $ -81.04\pm0.19 $ & $ 112.36\pm0.46 $ & & ... & ... & ... \\ 22 & 58.86 & 0.28 & 34\% & & $ -6.48\pm0.18 $ & $ -30.55\pm0.39 $ & & ... & ... & ... \\ 23 & 64.04 & 0.18 &... & & $ -68.46\pm0.42 $ & $ 103.02\pm0.58 $ & & ... & ... & ... \\ 24 & 59.12 & 0.17 &... & & $ 84.43\pm0.39 $ & $ -78.86\pm0.66 $ & & ... & ... & ... \\ 25 & 60.09 & 0.17 & 10\% & & $ -11.76\pm0.22 $ & $ -25.28\pm0.50 $ & & ... & ... & ... \\ 26 & 58.68 & 0.16 &... & & $ -17.03\pm0.63 $ & $ -94.58\pm0.91 $ & & ... & ... & ... \\ 27 & 59.12 & 0.16 & 17\% & & $ 26.70\pm0.24 $ & $ -18.15\pm0.63 $ & & ... & ... & ... \\ 28 & 58.07 & 0.14 & 19\% & & $ -396.02\pm0.25 $ & $ -39.64\pm0.64 $ & & ... & ... & ... \\ 29 & 63.07 & 0.13 & 44\% & & $ -213.83\pm0.28 $ & $ 195.95\pm0.63 $ & & ... & ... & ... \\ 30 & 57.63 & 0.12 &... & & $ -62.37\pm0.30 $ & $ -57.29\pm0.58 $ & & ... & ... & ... \\ 31 & 61.76 & 0.12 &... & & $ -68.25\pm0.42 $ & $ 93.82\pm0.77 $ & & ... & ... & ... \\ 32 & 60.70 & 0.11 &... & & $ -287.88\pm0.56 $ & $ -43.17\pm0.80 $ & & ... & ... & ... \\ 33 & 58.77 & 0.09 &... & & $ -7.14\pm0.97 $ & $ 68.86\pm1.10 $ & & ... & ... & ... \\ 34 & 61.32 & 0.09 & 15\% & & $ -68.81\pm0.33 $ & $ 122.23\pm0.80 $ & & ... & ... & ... \\ 35 & 63.25 & 0.08 &... & & $ -157.22\pm0.65 $ & $ 33.89\pm1.01 $ & & ... & ... & ... \\ 36 & 63.51 & 0.08 &... & & $ -209.00\pm0.54 $ & $ 104.94\pm1.03 $ & & ... & ... & ... \\ 37 & 63.69 & 0.08 &... & & $ -149.29\pm0.55 $ & $ 90.60\pm0.57 $ & & ... & ... & ... \\ 38 & 52.89 & 0.07 &... & & $ -407.11\pm0.65 $ & $ 669.44\pm1.07 $ & & ... & ... & ... \\ 39 & 56.84 & 0.06 &... & & $ -91.01\pm0.95 $ & $-124.54\pm1.31 $ & & ... & ... & ... \\ \par & & & & & & & & & &\\ 0 & & & & & $ -84.71 \pm 0.06$ & $ 67.90 \pm 0.10$ & & $ 0 $ & $ 0 $ & \\ \hline \multicolumn{10}{c}{Reference Feature: Absolute position}\\ \hline \noalign{\smallskip} Feature & \multicolumn{4}{c}{RA(J2000)} & \multicolumn{4}{c}{ Dec(J2000) } & & \\ & \multicolumn{4}{c}{(h m s)} & \multicolumn{4}{c}{(\degr $'$ $''$)} & & \\ \hline 2 &\multicolumn{4}{c}{18:21:09.13711~$\pm$~0.00023}&\multicolumn{4}{c}{$-$14:31:48.6853~$\pm$~0.0036} & & \\ \hline \end{tabular} \tablefoot{For each identified feature, the label (given in Col.~1) increases with decreasing brightness. Columns~2,~3, and~4 report the LSR velocity and brightness of the brightest spot and its percent brightness variability. Columns~5 and~6 give the position offset relative to the feature~\#~2, in the east and north directions, respectively. Columns~7 and~8 report the projected components of the feature proper motion relative to the center of motion (as defined in Sect.~\ref{ch3oh_results}, and identified with label~\#~0), along the east and north directions, respectively. Column~9 shows the relative error of the proper motion amplitude. The absolute position of the reference feature~\#~2 is reported at the bottom of the table.\\%[-1.5mm] \tablefoottext{a}{Variability (\%) = ($F_{\rm MAX} - F_{\rm MIN}$ of the brightest spot) / (($F_{\rm MAX} + F _{\rm MIN}$)/2.0)}.} \end{table}