\begin{table}%t1
%%\centering
\par
\caption{The XMM-{\it Newton} fields used for the selection of the HBS28 sample.}
\label{fields}
%\footnotesize
%\centerline
 {\begin{tabular}{c c r r l |c c r r l }
\hline
          \hline
obsid & position (J2000) & $t$ & $r_{\rm i}$ & $r_{\rm o}$ & obsid & position (J2000) & $t$ & $r_{\rm i}$ & $r_{\rm o}$ \\ 
      &                  & (s)         & ($^\prime$)  &  ($^\prime$) &       &                  & (s)         & ($^\prime$)  &  ($^\prime$)\\
            \hline
0125310101 & 00 00 30.4 $-$25 06 43.4 &    19163.6 &          1 &         13   &  0067340101 & 18 55 37.1 $-$46 30 57.6 &    10653.3 &  	0 &	    11  \\
0101040101 & 00 06 19.7 +20 12 22.8 &    34046.5 &          8 &         13  	  &0081341001 & 19 31 21.7 $-$72 39 13.3 &    15288.1 &  	1 &	    13  \\
0127110201 & 00 10 31.2 +10 58 40.7 &     7558.3 &          2 &         13  	  &0081340501 & 20 13 30.0 $-$41 47 25.7 &    19196.8 &  	0 &	    13  \\
0111000101 & 00 18 33.0 +16 26 08.0 &    31363.7 &          3 &         13  	  &0111180201 & 20 40 10.0 $-$00 52 14.7 &    16495.8 &  	8 &	    13  \\
0001930101 & 00 26 06.8 +10 41 12.5 &    18033.7 &          1 &         13  	  &0111510101 & 20 41 50.9 $-$32 26 19.8 &    15046.1 &  	8 &	    13  \\
0050140201 & 00 26 35.9 +17 09 37.8 &    50383.0 &          3 &         13  	  &0130720201 & 20 44 09.0 $-$10 43 11.2 &     5312.0 &  	8 &	    13  \\
0065770101 & 00 32 47.0 +39 34 33.3 &     7360.3 &          1 &         13  	  &0111420101 & 20 45 09.4 $-$31 20 36.6 &    43323.5 &  	8 &	    13  \\
0125320701 & 00 50 03.0 $-$52 07 36.7 &    16525.7 &          1 &         13   &  0112600501 & 20 46 20.0 $-$02 48 48.4 &    10550.3 &  	8 &	    13  \\
0110890401 & 00 57 20.0 $-$22 23 04.1 &    29743.3 &          8 &         13   &  0083210101 & 20 54 18.8 $-$15 55 38.2 &    10435.5 &  	2 &	    13  \\
0112650401 & 01 04 24.0 $-$06 24 10.6 &    23697.1 &          0 &         13   &  0112190601 & 20 56 21.6 $-$04 37 59.4 &    16639.4 &  	2 &	    13  \\
0103861601 & 01 05 16.4 $-$58 26 10.4 &     7127.5 &          8 &         13   &  0081340401 & 20 58 27.1 $-$42 38 56.9 &    15002.3 &  	1 &	    13  \\
0101040201 & 01 23 46.0 $-$58 48 25.8 &    28995.6 &          8 &         13   &  0041150101 & 21 04 11.1 $-$11 21 40.0 &    38736.2 &  	1 &	    13  \\
0109860101 & 01 25 33.4 +01 45 38.2 &    38535.6 &          4 &         13  	  &0038540301 & 21 04 40.2 $-$12 20 05.6 &    14698.6 &  	2 &	    13  \\
0112600601 & 01 27 32.1 +19 10 32.3 &     3994.4 &          8 &         13  	  &0088020201 & 21 27 38.1 $-$44 48 38.5 &    16094.7 &  	1 &	    13  \\
0084230301 & 01 31 53.7 $-$13 36 56.4 &    20447.4 &          8 &         13   &  0103060101 & 21 29 12.2 $-$15 38 34.7 &    22042.9 &  	3 &	    13  \\
0032140401 & 01 40 12.1 $-$67 48 40.3 &     7611.1 &          0 &         13   &  0109463501 & 21 37 56.5 $-$43 42 19.8 &     7577.7 &  	2 &	    13  \\
0093641001 & 01 43 01.7 +13 38 24.4 &     9329.0 &          4 &         13  	  &0061940201 & 21 38 07.9 $-$42 36 06.6 &     4868.2 &  	1 &	    13  \\
0101640201 & 01 59 50.2 +00 23 46.8 &     7543.7 &          8 &         13  	  &0008830101 & 21 40 15.5 $-$23 39 32.1 &    13986.7 &  	2 &	    13  \\
0084140101 & 02 08 38.2 +35 23 00.2 &    38003.5 &          2 &         13  	  &0103060401 & 21 51 55.9 $-$30 27 43.5 &    24072.9 &  	3 &	    13  \\
0112371701 & 02 17 12.4 $-$04 39 04.2 &    20002.1 &          0 &         11   &  0124930201 & 21 58 52.9 $-$30 13 28.8 &    36246.3 &  	8 &	    13  \\
0112371001 & 02 18 00.3 $-$04 59 47.8 &    50802.9 &          0 &         11   &  0130920101 & 22 03 09.3 +18 52 27.9 &    16491.3 &	      1 &	  13  \\
0112371501 & 02 18 48.3 $-$04 39 02.9 &     6684.6 &          0 &         11   &  0012440301 & 22 05 10.1 $-$01 55 11.2 &    30937.5 &  	2 &	    13  \\
0112370301 & 02 19 36.3 $-$04 59 47.7 &    50386.7 &          0 &         11   &  0106660101 & 22 15 31.9 $-$17 44 02.6 &    56911.8 &  	1 &	    13  \\
0098810101 & 02 36 12.3 $-$52 19 55.6 &    23451.5 &          2 &         13   &  0009650201 & 22 17 55.4 $-$08 20 58.0 &    21027.5 &  	8 &	    13  \\
0075940301 & 02 36 57.9 +24 38 53.7 &    47428.9 &          8 &         13  	  &0049340201 & 22 20 45.1 $-$24 40 58.1 &    26842.3 &  	6 &	    13  \\
0067190101 & 02 38 19.4 $-$52 11 34.1 &    25628.7 &          3 &         10   &  0018741701 & 22 34 32.9 $-$37 43 48.1 &     7080.3 &  	4 &	    13  \\
0111200101 & 02 42 41.1 $-$00 00 53.7 &    35486.8 &          8 &         13   &  0111790101 & 22 35 45.9 $-$26 03 00.4 &    41304.4 &  	4 &	    13  \\
0111490401 & 02 48 43.8 +31 06 59.2 &    31030.1 &          8 &         13  	  &0103860201 & 22 36 55.9 $-$22 13 10.1 &     8489.9 &  	8 &	    13  \\
0056020301 & 02 56 32.8 +00 06 01.7 &    17251.4 &          2 &         13  	  &0006810101 & 22 42 39.5 +29 43 35.6 &     7009.4 &	      8 &	  13  \\
0041170101 & 03 02 38.5 +00 07 31.9 &    47278.1 &          0 &         13  	  &0109070401 & 22 48 41.5 $-$51 09 57.9 &    14722.6 &  	8 &	    13  \\
0042340501 & 03 07 03.8 $-$28 40 24.1 &    13285.7 &          4 &         13   &  0112240101 & 22 49 48.3 $-$64 23 11.2 &    30608.4 &  	8 &	    13  \\
0122520201 & 03 11 59.3 $-$76 51 53.0 &    28296.4 &          2 &         13   &  0081340901 & 22 51 49.4 $-$17 52 17.0 &    22398.6 &  	1 &	    13  \\
0110970101 & 03 13 09.6 $-$55 03 48.4 &    10240.0 &          0 &         13   &  0112910301 & 22 53 58.8 $-$17 33 55.8 &     5301.3 &  	8 &	    13  \\
0105660101 & 03 17 56.0 $-$44 14 15.1 &    23151.9 &          6 &         13   &  0112170301 & 23 03 15.8 +08 52 25.9 &    23349.6 &	      4 &	  13  \\
0108060501 & 03 32 29.1 $-$27 48 27.1 &    46835.8 &          0 &         13   &  0109130701 & 23 04 43.6 $-$08 41 14.5 &    10615.6 &  	8 &	    13  \\
0099010101 & 03 35 27.6 $-$25 44 54.5 &    18777.9 &          8 &         13   &  0033541001 & 23 04 45.0 +03 11 35.6 &    12461.5 &	      2 &	  13  \\
0055140101 & 03 39 35.0 $-$35 25 58.1 &    47637.0 &          1 &         11   &  0123900101 & 23 13 58.9 $-$42 43 28.3 &    37401.3 &  	6 &	    13  \\
0111970301 & 04 09 07.2 $-$71 17 43.9 &    18741.3 &          8 &         13   &  0109463601 & 23 15 18.7 $-$59 10 31.7 &     5403.6 &  	8 &	    13  \\
0112600401 & 04 25 44.2 $-$57 13 34.4 &     7627.3 &          8 &         13   &  0112880301 & 23 31 49.9 +19 56 28.5 &    14318.0 &	      3 &	  13  \\
0103861701 & 04 35 17.1 $-$78 01 54.3 &     8010.9 &          8 &         13   &  0093550401 & 23 33 40.0 $-$15 17 12.2 &    22258.0 &  	1 &	    13  \\
0112880401 & 04 59 35.4 +01 47 16.0 &    18915.3 &          2 &         13  	  &0100241001 & 23 49 40.6 +36 25 30.6 &     8739.0 &	      3 &	  13  \\
                      \hline
\end{tabular}}
Column 1: observation ID; Col. 2: sky position of the center of the field; Col. 3: MOS2 exposure time 
(after having removed  the time intervals characterized 
by a high background);
Col. 4: inner radius (see text for details); 
Col. 5: outer radius (see text for details).
\end{table}