\begin{table}%ta1 \caption{\label{taba1}X-ray sources detected in CMa R1 by {\it ROSAT}.} %\centerline \begin{tabular}{cccccccccccccc} \hline\hline CMaX & Err&Cnt/ks & $S/N$ & log$L_{\rm x}$ & RA & Dec & $R$ & $A_V$ & $J$ & $H$ & $K$ & Age & Mass \\ & ($''$) & & & & J2000 & J2000 & (mag) & (mag) & (mag) & (mag) & (mag) & (Myr) & ($M_{\odot}$) \\ \hline \noalign{\smallskip} 1 & 30 & 16.7 $\pm$ 1.6 & 10.4 & 31.25 & 6 57 52.6 & $-11$ 27 23 & 9.7 & 1.0 & 8.9 & 8.7 & 8.6 & $<$1 & 3.0--5.0 \\ 2 & 30 & 5.0 $\pm$ 0.8 & 6.3 & 30.72 & 6 58 17.6 & $-11$ 37 10 & 15.7 & 1.0 & 14.5 & 13.9 & 13.8 & 05--10 & 1.0--1.5 \\ 3$^a$ & 30 & 17.9 $\pm$ 1.6 & 11.2 & 31.28 & 6 58 42.6 & $-11$ 42 00 & 9.0 & 0.5 & 8.4 & 8.2 & 8.1 & $<$1 & 3.0--5.0 \\ 4$^b$ & 30 & 19.4 $\pm$ 1.4 & 13.9 & 31.31 & 6 59 02.0 & $-11$ 00 38 & 10.8 & 0.4 & 11.5 & 11.4 & 11.4 & 05--10 & 1.5--2.0 \\ 5$^c$ & 30 & 5.0 $\pm$ 0.9 & 5.6 & 30.72 & 6 59 10.7 & $-11$ 40 03 & 8.3 & 0.5 & 7.7 & 7.5 & 7.4 & $<$1? & $>$5 \\ 6 & 30 & 7.0 $\pm$ 0.9 & 7.8 & 30.87 & 6 59 10.7 & $-11$ 57 30 & 13.0 & 1.0 & 11.2 & 10.8 & 10.7 & 02--05 & 2.0--3.0 \\ 7 & 30 & 5.1 $\pm$ 0.8 & 6.4 & 30.73 & 6 59 31.0 & $-11$ 58 18 & 11.8 & 0.9 & 11.0 & 10.6 & 10.6 & 02--05 & 2.0--3.0 \\ 8 & 20 & 2.4 $\pm$ 0.6 & 4.0 & 30.40 & 6 59 51.1 & $-11$ 15 52 & 12.7 & 0.5 & 11.2 & 10.7 & 10.5 & 01--02 & 2.0--3.0 \\ 9 & 12 & 1.4 $\pm$ 0.4 & 3.5 & 30.17 & (7 00 00.5) & ($-11$ 14 09) & -- & -- & -- & -- & -- & -- & -- \\ 10 & 30 & 5.1 $\pm$ 0.7 & 7.3 & 30.73 & 7 00 03.4 & $-11$ 47 45 & -- & -- & 9.6 & 9.6 & 9.6 & $<$ 1 & 3.0--5.0 \\ 11 & 10 & 2.8 $\pm$ 0.5 & 5.6 & 30.47 & 7 00 03.8 & $-11$ 15 26 & 14.8 & 0.4 & 13.7 & 13.2 & 13.0 & 20--50 & 1.0--1.5 \\ 12 & 5 & 3.7 $\pm$ 0.6 & 6.2 & 30.59 & 7 00 05.2 & $-11$ 31 46 & 14.8 & 0.8 & 13.4 & 12.8 & 12.7 & 05--10 & 1.0--1.5 \\ 13 & 12 & 1.2 $\pm$ 0.3 & 4.0 & 30.10 & 7 00 08.0 & $-11$ 37 00 & 14.9 & 0.5 & 14.1 & 13.4 & 13.2 & 05--10 & 1.0--1.5 \\ 14 & 12 & 2.2 $\pm$ 0.4 & 5.5 & 30.36 & 7 00 12.5 & $-11$ 34 33 & 16.6 & 0.8 & 13.8 & 13.1 & 12.9 & 02--05 & 1.0--1.5 \\ 15 & 10 & 1.9 $\pm$ 0.4 & 4.8 & 30.30 & (7 00 14.5) & ($-11$ 18 51) & -- & -- & -- & -- & -- & -- & -- \\ 16 & 10 & 2.0 $\pm$ 0.5 & 4.0 & 30.32 & 7 00 17.0 & $-11$ 08 03 & 13.7 & 0.4 & 12.6 & 12.4 & 12.3 & $>$50 & 1.5--2.0 \\ 17 & 9 & 1.3 $\pm$ 0.3 & 4.3 & 30.14 & (7 00 19.8) & ($-11$ 23 20) & -- & -- & - - & -- & -- & -- & -- \\ 18 & 8 & 1.1 $\pm$ 0.3 & 3.7 & 30.06 & 7 00 26.5 & $-11$ 26 33 & 14.9 & 0.8 & 13.1 & 12.4 & 12.2 & 02--05 & 1.0--1.5 \\ 19 & 30 & 4.6 $\pm$ 0.8 & 5.8 & 30.69 & 7 00 27.1 & $-11$ 51 26 & 13.4 & 0.8 & 12.4 & 12.1 & 12.0 & 10--20 & 1.5--2.0 \\ 20$^d$ & 5 & 62.7 $\pm$ 1.9 & 33.0 & 31.82 & 7 00 37.6 & $-11$ 14 45 & 7.8 & 0.7 & 6.6 & 6.0 & 5.9 & $<$1? & $>$5 \\ 21 & 30 & 41.6 $\pm$ 1.9 & 21.9 & 31.64 & 7 00 40.4 & $-11$ 04 35 & 12.3 & 0.9 & 10.6 & 9.9 & 9.7 & $<$1 & 1.0--1.5 \\ 22 & 6 & 2.0 $\pm$ 0.4 & 5.0 & 30.32 & (7 00 41.3) & ($-11$ 34 50) & -- & -- & -- & -- & -- & -- & -- \\ 23 & 5 & 3.4 $\pm$ 0.5 & 6.8 & 30.55 & 7 00 43.4 & $-11$ 17 14 & 14.3 & 0.5 & 12.9 & 12.3 & 12.2 & 02--05 & 1.5--2.0 \\ 24$^*$ & 8 & 1.1 $\pm$ 0.4 & 2.8 & 30.06 & 7 00 45.4 & $-11$ 31 00 & 16.9 & 0.5 & 15.9 & 15.6 & 15.0 & ?? & ?? \\ 25 & 8 & 0.4 $\pm$ 0.2 & 2.0 & 29.62 & 7 00 45.5 & $-11$ 20 29 & 17.0 & 0.8 & 16.0 & 15.7 & 15.6 & ?? & ?? \\ 26 & 12 & 1.2 $\pm$ 0.3 & 4.0 & 30.10 & 7 00 54.6 & $-11$ 34 12 & 14.0 & 0.8 & 13.2 & 12.8 & 12.7 & 20--50 & 1.0--1.5 \\ 27$^*$ & 10 & 2.2 $\pm$ 0.5 & 4.4 & 30.36 & 7 00 55.5 & $-11$ 21 45 & 15.7 & 0.7 & 14.6 & 14.3 & 14.1 & 01--02 & 0.1--0.5 \\ 28 & 8 & 0.9 $\pm$ 0.3 & 3.0 & 29.98 & 7 00 55.8 & $-11$ 26 25 & 15.8 & 0.8 & 13.6 & 12.8 & 12.6 & ?? & ?? \\ 29 & 5 & 2.5 $\pm$ 0.4 & 6.3 & 30.42 & 7 01 00.8 & $-11$ 19 29 & 15.4 & 1.0 & 12.8 & 12.1 & 11.9 & $<$1 & 0.5--1.0 \\ 30 & 12 & 2.1 $\pm$ 0.5 & 4.2 & 30.34 & 7 01 04.1 & $-11$ 39 48 & 16.4 & 0.7 & 15.2 & 14.4 & 14.2 & 05--10 & 0.1--0.5 \\ 31 & 9 & 0.8 $\pm$ 0.3 & 2.7 & 29.93 & 7 01 06.9 & $-11$ 31 23 & 10.6 & 0.7 & 9.4 & 9.0 & 8.8 & $<$1 & 3.0--5.0 \\ 32 & 8 & 2.1 $\pm$ 0.4 & 5.3 & 30.34 & 7 01 11.2 & $-11$ 27 50 & 11.4 & 0.9 & 10.8 & 10.6 & 10.5 & 02--05 & 2.0--3.0 \\ 33 & 15 & 0.9 $\pm$ 0.3 & 3.0 & 29.98 & 7 01 13.1 & $-11$ 21 01 & 16.4 & 1.0 & 14.9 & 14.4 & 14.3 & ?? & ?? \\ 34 & 8 & 1.3 $\pm$ 0.3 & 4.3 & 30.14 & 7 01 16.3 & $-11$ 25 58 & 15.2 & 1.0 & 13.7 & 13.0 & 12.9 & 05--10 & 1.0--1.5 \\ 35 & 8 & 0.7 $\pm$ 0.3 & 2.3 & 29.87 & 7 01 20.1 & $-11$ 17 44 & 15.6 & 0.7 & 13.3 & 12.9 & 12.8 & 20--50 & 1.0--1.5 \\ 36 & 15 & 1.1 $\pm$ 0.3 & 3.7 & 30.06 & 7 01 24.4 & $-11$ 09 06 & 16.2 & 0.5 & 14.8 & 14.2 & 14.1 & 20--50 & 0.5--1.0 \\ 37 & 15 & 2.1 $\pm$ 0.4 & 5.3 & 30.34 & (7 01 25.0) & ($-11$ 08 50) & -- & -- & -- & -- & -- & -- & -- \\ 38 & 5 & 3.5 $\pm$ 0.4 & 8.8 & 30.57 & 7 01 26.8 & $-11$ 28 21 & 13.5 & 0.8 & 12.3 & 12.0 & 11.9 & 10--20 & 1.5--2.0 \\ 39 & 8 & 0.8 $\pm$ 0.3 & 2.7 & 29.93 & 7 01 29.2 & $-11$ 21 30 & 15.4 & 0.8 & 14.1 & 13.5 & 13.5 & 10--20 & 1.0--1.5 \\ 40 & 10 & 2.0 $\pm$ 0.4 & 5.0 & 30.32 & 7 01 30.4 & $-11$ 22 29 & 16.9 & 1.2 & 15.4 & 14.8 & 14.8 & ?? & ?? \\ 41 & 8 & 1.6 $\pm$ 0.4 & 4.0 & 30.23 & 7 01 34.0 & $-11$ 25 33 & 15.3 & 0.8 & 13.8 & 13.2 & 13.1 & 10--20 & 1.0--1.5 \\ 42 & 10 & 1.8 $\pm$ 0.4 & 4.5 & 30.28 & (7 01 34.3) & ($-11$ 11 16) & -- & -- & -- & --& -- & -- & -- \\ 43 & 15 & 0.6 $\pm$ 0.3 & 2.0 & 29.80 & 07 01 35.1 & $-11$ 36 38 & 14.3 & 1.3 & 12.1 & 11.8 & 11.7 & 10--20 & 1.5--2.0 \\ 44 & 8 & 1.2 $\pm$ 0.3 & 4.0 & 30.10 & 7 01 35.8 & $-11$ 17 36 & 13.6 & 0.8 & 12.8 & 12.5 & 12.4 & 10--20 & 1.0--1.5 \\ 45 & 10 & 1.2 $\pm$ 0.4 & 3.0 & 30.10 & 7 01 41.1 & $-11$ 32 57 & 12.9 & 1.0 & 12.2 & 11.9 & 11.9 & 10--20 & 1.5--2.0 \\ 46 & 15 & 1.4 $\pm$ 0.4 & 3.5 & 30.17 & (7 01 43.0) & ($-11$ 10 20) & -- & -- & -- & -- & -- & -- & -- \\ 47 & 8 & 2.1 $\pm$ 0.4 & 5.3 & 30.34 & 7 01 45.9 & $-11$ 30 33 & 15.4 & 0.7 & 13.4 & 12.7 & 12.5 & 01--02 & 0.5--1.0 \\ 48$^e$ & 15 & 2.7 $\pm$ 0.4 & 6.8 & 30.45 & 7 01 49.3 & $-11$ 18 07 & 7.5 & 1.7 & 6.3 & 6.2 & 6.0 & ?? & ?? \\ 49 & 9 & 1.5 $\pm$ 0.4 & 3.8 & 30.20 & 7 01 49.5 & $-11$ 16 41 & 12.2 & 1.7 & 10.8 & 10.3 & 10.2 & 02--05 & 2.0--3.0 \\ 50 & 12 & 1.1 $\pm$ 0.3 & 3.7 & 30.06 & 7 01 52.4 & $-11$ 20 18 & 13.4 & 1.3 & 12.1 & 11.7 & 11.5 & 05--10 & 1.5--2.0 \\ 51 & 8 & 1.3 $\pm$ 0.4 & 3.3 & 30.14 & 7 01 56.3 & $-11$ 24 07 & 16.5 & 1.2 & 14.3 & 13.6 & 13.4 & 10--20 & 1.0--1.5 \\ 52 & 8 & 2.3 $\pm$ 0.4 & 5.8 & 30.38 & 7 01 58.7 & $-11$ 15 45 & 13.5 & 1.7 & 12.3 & 11.6 & 11.5 & 01--02 & 2.0--3.0 \\ 53 & 14 & 1.5 $\pm$ 0.4 & 3.8 & 30.20 & 7 02 04.4 & $-11$ 19 44 & 14.1 & 1.2 & 13.4 & 13.0 & 12.9 & $>$50 & 05--1.0 \\ 54 & 15 & 0.5 $\pm$ 0.3 & 1.7 & 29.72 & (7 02 05.5) & ($-11$ 26 50) & -- & -- & -- & -- & -- & -- & -- \\ 55 & 30 & 0.6 $\pm$ 0.3 & 2.0 & 29.80 & (7 02 07.4) & ($-11$ 17 11) & -- & -- & -- & -- & -- & -- & -- \\ 56 & 30 & 5.3 $\pm$ 0.8 & 6.6 & 30.75 & 7 02 38.9 & $-11$ 30 39 & 12.8 & 0.9 & 9.9 & 8.9 & 8.6 & ?? & ?? \\ 57$^f$ & 30 & 2.3 $\pm$ 1.0 & 2.3 & 30.40 & 7 02 42.6 & $-11$ 27 12 & 8.0 & 1.6 & 7.8 & 7.8 & 7.7 & $<$1? & $>$5 \\ 58 & 30 & 2.0 $\pm$ 1.0 & 2.0 & 30.32 & 7 02 47.3 & $-11$ 28 08 & 16.6 & 1.6 & 14.9 & 14.3 & 14.1 & $>$50 & 1.0--1.5 \\ 59 & 30 & 1.9 $\pm$ 1.0 & 2.0 & 30.31 & 7 02 51.3 & $-11$ 24 03 & 17.5 & 4.0 & 14.6 & 13.7 & 13.4 & 05--10 & 1.0--1.5 \\ \hline \end{tabular} \smallskip \par Columns description: (1) Source name: CMaX~1 to 56 (Field~1), CMaX~62 to 98 (Field~2), CMaX~57 to 61 (both fields); (2--5) X-ray data; (6,~7)~Coordinates of the optical counterpart, when available; (8, 9) $R$ magnitude and visual extinction ($A_V$), obtained from available catalogues; (10--12)~Near-IR magnitudes from the 2MASS catalogue; (13, 14) The estimation of age and mass is based on near-IR. \par Notes: Stars previously identified (Clari\'a 1974, indicated by ``C and Shevchenko et~al. \cite{Shevchenko1999}, indicated by ``SEI''): (a) HD~51896 (F5), (b) SS~75, (c)~HD~52014 (F5), (d) HD~52385 (K0), (e) GU~CMa, HD~52721 (B2V), C~63 , SEI~158; (f) FZ ~CMa (B2.5), C~67, SEI~159; (g) Z~CMa (Bpe), C~76, SEI~161; (h) BD~-111762 (B2), C~77, SEI~92; (i) C~14, SEI~94. Members of clusters: (j) vdB-RN92, (k) BRC~27. Objects detected by {\it XMM-Newton} and/or {\it Chandra} are indicated by ``x''. Relevant sources: (*) $H-K$ excess. \end{table}