\begin{table}%t1 \caption{\label{n4861hiparams}\HI\ properties as measured from the VLA data.} %\centerline {\small \begin{tabular}{lcc} \hline \hline \noalign{\smallskip} Parameters [Unit] & NGC~4861 & NGC~4861 B\\ \hline \noalign{\smallskip} optical centre$^a$: & &\\ ~~$\alpha$ (J2000.0) & 12$\rm ^h$59$\rm ^m$02.3$\rm ^s$ &\\ ~~$\delta$ (J2000.0) & +34\degr 51\arcmin 34\arcsec&\\ $D$ [Mpc]$^b$ & 7.5 &\\ \hline \noalign{\smallskip} dynamic centre$^c$: & &\\ ~~$\alpha$ (J2000.0) & 12$\rm ^h$59$\rm ^m$01.4$\rm ^s$ & 12$\rm ^h$59$\rm ^m$32.6$\rm ^s$\\ ~~$\delta$ (J2000.0) & +34\degr 51\arcmin 43\arcsec & +34\degr 51\arcmin 15\arcsec\\ \vsys\ [\kms]$^c$ & $835\pm 1$ & 791\\ $i$ [\degr]$^c$ & $65\pm 3$ & 65\\ PA [\degr]$^c$ & $16\pm 3$ & 244\\ \hline \noalign{\smallskip} \vrot\ [\kms]$^c$ & 46 & 4.4\\ $F_{\rm HI}$ [Jy \kms] & 36.08 & 0.30\\ $M_{\rm HI}$ [$\rm 10^8$~\Msun] & 4.79 & 0.04\\ \HI\ diameter [\arcmin] & 7.0 $\rm \times$ 4.9 & 1.6 $\rm \times$ 0.9\\ ~~~~~~~~~"~~~~~~~~~ [kpc] & 15.2 $\rm \times$ 10.7 & 3.6 $\rm \times$ 1.9\\ \HI\ / opt. ratio & 2.3 $\rm \times$ 5& ...\\ $\langle\sigma\rangle$ [\kms] & 14 & 7\\ $\sigma_{\rm Peak}$ [\kms] & 22.8 & 9.9\\ $r_{\rm HI,max}$ [kpc] & 10.9 & 2.7\\ $M_{\rm dyn}$ [$\rm 10^9$~\Msun] & 5.4 & 0.012\\ \hline \end{tabular}} \par \medskip $^a$~Data from NED; $^b$~distance from \citet{deVaucouleurs1991}; $^c$~derived by fitting a tilted-ring model to the \HI\ data. In case of NGC~4861, where all parameters were fitted iteratively, the error weighted mean values plus uncertainties are given. The errors of the dynamic centre position are far below one beam size. The parameters of NGC~4861~B were estimated from fitting ellipses to the \HI\ distribution. \end{table}