\begin{table}%td1
  \caption{\label{tab:diag1}Diagnostic line ratios, see text for the columns definitions.} 
%\centering
\par
  \begin{tabular}{lrrr}
    \hline    \hline
    \multicolumn{1}{c}{\textbf{I}} 
    & \multicolumn{1}{c}{\textbf{II}}
    & \multicolumn{1}{c}{\textbf{III}}
    & \multicolumn{1}{c}{\textbf{IV}}\\
    \hline
R  O  2 2471/7325+     & {\bf     0.7635}&    0.7635&{\it      --0.00}\\
 Ne S  2 6731/6716      & {\bf     2.1250}&    2.0641&{\it      --0.12}\\
 Ne S  2 6731/6716 HAF  & {\bf     1.8914}&    2.0693&{\it       0.25}\\
 Ne S  2 6731/6716 GCM  & {\bf     2.0431}&    2.0588&{\it       0.02}\\
 Ne O  2 3726/3729      & {\bf     2.3653}&    2.5433&{\it       0.55}\\
 Ne O  2 3726/3729 HAF  & {\bf     2.4000}&    2.5500&{\it       0.24}\\
 Ne S  3 18.7/33.5      & {\bf     5.8102}&    6.1838&{\it       0.15}\\
 Ne Cl 3 5538/5518      & {\bf     1.9560}&    1.9852&{\it       0.04}\\
 Ne Cl 3 5538/5518 HAF  & {\bf     2.0000}&    2.0465&{\it       0.05}\\
 Ne Cl 3 5538/5518 GCM  & {\bf     2.2222}&    1.9420&{\it      --0.30}\\
 Ne O  3 51.9/88.4      & {\bf     6.3413}&    7.2426&{\it       0.33}\\
 Ne Ar 4 4740/4711      & {\bf     1.2000}&    1.7769&{\it       1.11}\\
 Te S  2 4068+/6731+    & {\bf     0.3915}&    0.5367&{\it       1.56}\\
 Te S  2 4068+/6731+HAF & {\bf     0.3198}&    0.5540&{\it       1.92}\\
 Te Cl 2 6162/9124+     & {\bf     0.0108}&    0.0182&{\it       1.60}\\
 Te O  2 7320+/3727+    & {\bf     0.1433}&    0.1949&{\it       3.10}\\
 Te O  2 7320+/3727+HAF & {\bf     0.2266}&    0.2042&{\it      --0.55}\\
 Te N  2 5755/6584+     & {\bf     0.0127}&    0.0124&{\it      --0.15}\\
 Te N  2 5755/6584+ HAF & {\bf     0.0141}&    0.0128&{\it      --0.32}\\
 Te S  3 6312/9531+     & {\bf     0.0143}&    0.0133&{\it      --0.25}\\
 Te S  3 6312/9531+ HAF & {\bf     0.0179}&    0.0141&{\it      --0.67}\\
 Te S  3 6312/18.7      & {\bf     0.0564}&    0.0543&{\it      --0.11}\\
 Te Ar 3 7136/8.99      & {\bf     1.1262}&    0.9620&{\it      --0.43}\\
 Te Ar 3 5192/7136+     & {\bf     0.0037}&    0.0036&{\it      --0.10}\\
 Te Ar 3 5192/7136+ HAF & {\bf     0.0043}&    0.0037&{\it      --0.39}\\
 Te N  3 1750/57.4      & {\bf     0.1757}&    0.2336&{\it       0.58}\\
 Te O  3 4363/5007+     & {\bf     0.0033}&    0.0027&{\it      --0.68}\\
 Te O  3 4363/5007+ HAF & {\bf     0.0045}&    0.0028&{\it      --1.32}\\
 Te O  3 4363/5007+ GCM & {\bf     0.0045}&    0.0027&{\it      --1.40}\\
 Te O  3 5007+/88.3     & {\bf   119.1307}&  140.8424&{\it       0.49}\\
 Te O  3 5007+/88.3 HAF & {\bf    47.9473}&   80.5872&{\it       1.45}\\
 Te Ne 3 3869+/15.5     & {\bf     0.4268}&    0.3934&{\it      --0.23}\\
 Te Ne 3 3869+/15.5 HAF & {\bf     0.2828}&    0.1607&{\it      --1.47}\\
    \hline
  \end{tabular}
\end{table}