\begin{table}%t3
\caption{\label{tab3}Spatial and kinematic characteristics of the three pairs of parallel PdBI-only structures.}
\small%\centerline
 {
\begin{tabular}{lllllllll}
\hline\hline 
&&&&&&&& \\[-8pt]
Pair & $v_{1}$ & $v_{2}$ & $\delta v_{\rm LSR}$  & $\delta l_{\perp}$ $^a$ & $\delta v/\delta l_{\perp}$ & $a$ $^b$ & $\tau$ $^c$ & $l$ $^d$    \\
  & \kms\ & \kms\ & \kms\ & mpc & \kmspc\ & s$^{-1}$ & yr & mpc  \\
\hline
&&&&&&&& \\[-8pt]
\#3, \#8 & --5.0 & --1.5 &  3.5 & 4.5  & 777   & $1.3\times 10^{-11}$ & $2.5\times 10^3$ & 45  \\
\#1, \#5 & --5.4 & --3.0 &  2.4 & 9.0 & 267 & $4.5\times 10^{-12}$ & $4\times 10^3$ & 45   \\
\#6, \#7 & --3.0 & --3.1 &  0.1 & 16 & 6 & $10^{-13}$ & $3\times 10^5$ & 40   \\
\hline
\end{tabular}}
\medskip
$^a$~Averaged separation between the PdBI CO~peaks;
$^b$~$a= {1 \over 2} \delta v/\delta l_{\perp}$;
$^c$~$\tau=a^{-1}$;
$^d$~length over which the structures are parallel within~${\pm}10\deg$.
\end{table}