\begin{table}%t2
%\centering
\par
\caption {\label{tab2}$u-r$ colour and  emission-line fluxes of the galaxies with ionised gas. The horizontal line divides \hi~detections from non-detections. For the objects not included in the SDSS spectroscopic sample, the fluxes have been taken from the values reported in the literature. The  references are indicated in the last column and they correspond to: 1.  SDSS \citep[]{2002AJ....124.1810S}; 2. \citet{2005ApJ...634..210G}; 3. \citet{1997ApJS..112..315H}; 4. \citet{2006ApJS..164...81M}.}
\begin{tabular}{lccrcccccc}
 \hline \hline
           ID  & & $u-r$ &&       H$\beta$ $\: $ &    O[III]$_{5007}$   &  H$\alpha$ $\: $ & N[II]$_{6583}$     & & Ref.\\
             & &     &&     $10^{-17}$~erg s$^{-1}$~cm$^{-2}$   & $10^{-17}$~erg s$^{-1}$~cm$^{-2}$   &$10^{-17}$~erg s$^{-1}$~cm$^{-2}$  &$10^{-17}$~erg s$^{-1}$~cm$^{-2}$  & &  \\
\hline  
                  MRK~0706  & & 1.62 && 2671 $\pm$ 37 &  5035 $\pm$ 62 &  10850 $\pm$ 125 &   1981 $\pm$ 30    & & 1\\
  SDSS~J093608.59+061525.4  & &  1.41 && 74 $\pm$  4 &    151 $\pm$  6 &    347  $\pm$  7 &   57  $\pm$ 4  & & 1 \\
                  NGC~2962  & & 2.85 && --       &   --           &    20       & 130   & & 2\\
  SDSS~J104926.70+121528.0  & & 1.02 && 260 $\pm$  8 &   892 $\pm$  14 &    857 $\pm$  14 &   40 $\pm$  4 & & 1\\
                  NGC~3489  & & 3.73 && 1488   &    4367    &     3235           &   4302         & & 3\\
                    IC~676  & & 2.00 && 589 $\pm$  17  &    175 $\pm$ 16 &   4071 $\pm$ 57 &  1921 $\pm$ 34 & & 1\\
  SDSS~J111445.02+123851.7  & & 1.27 && 1.5 $\pm$ 1.3   &    10 $\pm$ 3 &     19  $\pm$ 2  &    3.0  $\pm$ 2  & & 1\\
                    IC~692  & & 1.23 && 165 $\pm$  21  &   563 $\pm$  23 &    753 $\pm$  9  &  120 $\pm$  11  & & 1\\
   2MASX~J11434609+1342273  & & 1.89 && 832 $\pm$  14  &   641 $\pm$  11 &   4187 $\pm$ 53 &  1286 $\pm$  17 & & 1\\
                  NGC~3773  & & 1.13 && (271 $\pm$ 11)~$\times 10^2$    &   (355 $\pm$ 15)~$\times 10^2$   &     (879 $\pm$ 35)~$\times 10^2$        &  (157 $\pm$ 7)~$\times 10^2$     & & 4\\
                  UGC~6655  & & 1.28 && 1635 $\pm$ 31  &  5352 $\pm$ 96 &   5563 $\pm$ 67 &   515 $\pm$  12 & & 1\\
   2MASX~J11460404+1134529  & & 1.22 && 1135 $\pm$  20  &  3294 $\pm$ 43 &   4294 $\pm$ 47 &    424$\pm$  12 & & 1\\
                  NGC~5338  & & 1.91 && 407 $\pm$ 15  &   531 $\pm$  18 &    2742 $\pm$  19  &  893 $\pm$  21 & & 1\\
  SDSS~J144329.18+043153.4  & & 1.68 &&  9 $\pm$  2  &     16 $\pm$  2 &     41 $\pm$  2 &     5 $\pm$  1 & & 1\\
\hline
                  UGC~4590  & & 2.23 &&   48 $\pm$ 5  &     16 $\pm$  5 &   507  $\pm$ 11  &   176  $\pm$ 9   & & 1 \\
  SDSS~J095036.25+124832.7  & & 1.64 &&  9 $\pm$  5 &     25 $\pm$  5 &     92 $\pm$  3 &   17 $\pm$  3 & & 1 \\
              CGCG064-055  & & 1.34 && 200 $\pm$  11 &  2714 $\pm$  42 &   1810 $\pm$  17 &  1507 $\pm$ 34 & & 1\\
  SDSS~J102339.36+123725.6  & & 1.85 &&  17 $\pm$  3 &    33 $\pm$  4 &     94 $\pm$  3  &   18 $\pm$  3 & & 1\\
    MAPS-NGPO\_559\_1243538 & & 1.82 &&  28 $\pm$  4   &   72 $\pm$  5  &    124 $\pm$  3  &    11 $\pm$  3 & & 1 \\
 \hline
\end{tabular}
\end{table}