Table 7: Final list of X-ray sources identified with stars attributed to cluster NGC 2451 A, yielding Williams number (W #), mean X-ray positions (J2000), offset ( $\Delta$ ) between X-ray and optical positions in arcsec, V magnitudes, measured B-V and de-reddened (B-V)₀ colour indices. An asterisk indicates values from the literature used for bright stars that are overexposed in our images. Where significant variations in the X-ray flux have been found an X is written into the Var column. Spectral types are given in parentheses if estimated from the colour index. The last column gives a common star designation.
X # W # RA DEC $\Delta$ V B-V (B-V)₀ Var log $L_{\rm x}$ log $\frac{L_{\rm x}}{L_{\rm bol}}$ Spec. Notes

X3 7 46 09 -37 24 45 48 10.66* 0.52* 0.51 28.88 -4.92 (F8V)

X11 256 7 45 28 -37 35 41 9 6.91* -0.05* -0.06 29.38 -6.01 B9V HD 63079

X22 7 46 54 -37 43 07 10 16.72 1.52 1.51 29.27 -2.78 (M2V)

X30 7 44 16 -37 45 59 34 13.15 1.06 1.05 29.04 -3.99 (K4V)

X31 68 7 45 38 -37 46 39 5 11.46 0.65 0.64 X 29.91 -3.65 (G3V) CD-37 3870

X32 7 43 55 -37 46 37 6 16.42 1.52 1.51 29.12 -3.05 (M2V)

X40 7 45 05 -37 48 07 1 15.49 1.38 1.37 28.99 -3.31 (K8V)

X59 7 46 29 -37 52 37 16 17.36 1.54 1.53 28.99 -2.82 (M2V)

X61 251 7 45 05 -37 53 16 1 6.53* -0.11* -0.12 - - B3IV HD 62991

X63 15 7 43 49 -37 53 46 1 10.57* 0.52* 0.51 29.19 -4.68 (F8V) CD-37 3823

X72 7 45 16 -37 54 39 2 12.38 0.76 0.75 X 29.74 -3.45 (G8V)

X80 267 7 46 10 -37 56 01 4 5.87* -0.09* -0.10 29.38 -6.54 B7V HD 63215

X83 7 45 05 -37 56 35 2 15.42 1.34 1.33 28.94 -3.34 (K8V)

X84 246 7 44 34 -37 56 36 3 5.89* -0.10* -0.11 - - B7V HD 62893

X97 7 47 42 -37 58 43 33 11.86* 0.73* 0.72 29.20 -4.22 (G8V)

X102 7 44 07 -37 59 24 1 16.43 1.51 1.50 29.30 -2.85 (M1V)

X103 244 7 44 28 -37 59 16 1 8.62* 0.12* 0.11 29.55 -5.06 A3V HD 62876

X106 7 43 54 -38 00 03 1 12.30 0.81 0.80 29.46 -3.77 (K0V)

X108 7 46 25 -38 00 09 20 14.57 1.37 1.36 28.82 -3.88 (K8V)

X109 46 7 44 56 -38 00 18 4 9.80* 0.54* 0.53 28.80 -5.29 (F8V) CD-37 3853

X114 7 46 24 -38 01 04 11 12.71 0.89 0.88 28.52 -4.65 (K1V)

X116 50 7 45 02 -38 02 24 4 10.01 0.42 0.41 28.82 -5.22 (F5V) CD-37 3859

X117 7 48 07 -38 02 10 9 12.54 0.86 0.85 30.06 -3.09 (K1V)

X128 7 45 05 -38 04 29 0 17.67 1.54 1.53 X 28.94 -2.79 (M2V)

X132 47 7 44 60 -38 05 43 5 8.30* 0.15* 0.14 29.77 -4.96 A3V HD 62974

X134 3 7 42 46 -38 05 54 23 10.84* 0.56* 0.55 X 29.42 -4.34 (F8V) CPD-37 1499

X142 89 7 46 35 -38 06 43 4 10.01* 0.33* 0.32 29.69 -4.37 (F0V) CD-37 3897

X144 7 43 51 -38 07 06 5 15.92 1.49 1.48 29.36 -2.93 (M1V)

X149 94 7 46 49 -38 08 50 15 9.46* 0.43* 0.42 29.27 -5.04 (F5V) CD-37 3902

X151 7 43 06 -38 09 19 3 15.34 1.39 1.38 X 29.65 -2.73 (M0V)

X152 7 45 22 -38 09 51 39 13.21 0.98 0.97 28.52 -4.49 (K3V)

X156 57 7 45 15 -38 11 50 3 11.00 0.56 0.55 X 30.31 -3.38 (F8V) CD-37 3862

X157 233 7 43 43 -38 12 14 10 6.35* -0.09* -0.10 29.19 -6.51 B9Vsp HD 62712

X160 7 47 04 -38 12 31 10 16.32 1.56 1.55 29.38 -2.93 (M3V)

X173 7 43 52 -38 16 20 20 14.89 1.50 1.49 29.58 -3.15 (M1V)

X177 7 48 15 -38 22 35 48 11.29 0.61 0.60 30.27 -3.32 (G0V)

X181 7 43 58 -38 27 48 25 13.55 1.11 1.10 X 29.61 -3.21 (K4V)

X187 7 45 50 -38 33 55 38 12.58 0.84 0.83 29.81 -3.31 (K0V)

X188 7 44 25 -38 35 49 22 10.95* 0.61* 0.60 X 30.09 -3.64 (G0V)

Notes on individual objects:
X61: HRI detection only; UV contamination assumed.
X63: probably non-member due to lower metallicity (Hünsch et al. 2003).
X84: HRI detection only; UV contamination assumed.
X109: possibly foreground star; soft X-ray source, slightly above the main sequence, lower Li abundance (Hünsch et al. 2003).
X128: flare star; X-ray parameters given for quiescent state.
X151: flare star; X-ray parameters given for quiescent state.
X156: close visual binary, not resolved in X-rays.
X177: close visual binary, not resolved in X-rays.

**Table 7:** Final list of X-ray sources identified with stars attributed to cluster NGC 2451 A, yielding Williams number (W #), mean X-ray positions (J2000), offset ( $\Delta$ ) between X-ray and optical positions in arcsec, V magnitudes, measured B-V and de-reddened (B-V)₀ colour indices. An asterisk indicates values from the literature used for bright stars that are overexposed in our images. Where significant variations in the X-ray flux have been found an X is written into the Var column. Spectral types are given in parentheses if estimated from the colour index. The last column gives a common star designation.
X #	W #	RA	DEC	$\Delta$	V	B-V	(B-V)₀	Var	log $L_{\rm x}$	log $\frac{L_{\rm x}}{L_{\rm bol}}$	Spec.	Notes
X3		7 46 09	-37 24 45	48	10.66*	0.52*	0.51		28.88	-4.92	(F8V)
X11	256	7 45 28	-37 35 41	9	6.91*	-0.05*	-0.06		29.38	-6.01	B9V	HD 63079
X22		7 46 54	-37 43 07	10	16.72	1.52	1.51		29.27	-2.78	(M2V)
X30		7 44 16	-37 45 59	34	13.15	1.06	1.05		29.04	-3.99	(K4V)
X31	68	7 45 38	-37 46 39	5	11.46	0.65	0.64	X	29.91	-3.65	(G3V)	CD-37 3870
X32		7 43 55	-37 46 37	6	16.42	1.52	1.51		29.12	-3.05	(M2V)
X40		7 45 05	-37 48 07	1	15.49	1.38	1.37		28.99	-3.31	(K8V)
X59		7 46 29	-37 52 37	16	17.36	1.54	1.53		28.99	-2.82	(M2V)
X61	251	7 45 05	-37 53 16	1	6.53*	-0.11*	-0.12		-	-	B3IV	HD 62991
X63	15	7 43 49	-37 53 46	1	10.57*	0.52*	0.51		29.19	-4.68	(F8V)	CD-37 3823
X72		7 45 16	-37 54 39	2	12.38	0.76	0.75	X	29.74	-3.45	(G8V)
X80	267	7 46 10	-37 56 01	4	5.87*	-0.09*	-0.10		29.38	-6.54	B7V	HD 63215
X83		7 45 05	-37 56 35	2	15.42	1.34	1.33		28.94	-3.34	(K8V)
X84	246	7 44 34	-37 56 36	3	5.89*	-0.10*	-0.11		-	-	B7V	HD 62893
X97		7 47 42	-37 58 43	33	11.86*	0.73*	0.72		29.20	-4.22	(G8V)
X102		7 44 07	-37 59 24	1	16.43	1.51	1.50		29.30	-2.85	(M1V)
X103	244	7 44 28	-37 59 16	1	8.62*	0.12*	0.11		29.55	-5.06	A3V	HD 62876
X106		7 43 54	-38 00 03	1	12.30	0.81	0.80		29.46	-3.77	(K0V)
X108		7 46 25	-38 00 09	20	14.57	1.37	1.36		28.82	-3.88	(K8V)
X109	46	7 44 56	-38 00 18	4	9.80*	0.54*	0.53		28.80	-5.29	(F8V)	CD-37 3853
X114		7 46 24	-38 01 04	11	12.71	0.89	0.88		28.52	-4.65	(K1V)
X116	50	7 45 02	-38 02 24	4	10.01	0.42	0.41		28.82	-5.22	(F5V)	CD-37 3859
X117		7 48 07	-38 02 10	9	12.54	0.86	0.85		30.06	-3.09	(K1V)
X128		7 45 05	-38 04 29	0	17.67	1.54	1.53	X	28.94	-2.79	(M2V)
X132	47	7 44 60	-38 05 43	5	8.30*	0.15*	0.14		29.77	-4.96	A3V	HD 62974
X134	3	7 42 46	-38 05 54	23	10.84*	0.56*	0.55	X	29.42	-4.34	(F8V)	CPD-37 1499
X142	89	7 46 35	-38 06 43	4	10.01*	0.33*	0.32		29.69	-4.37	(F0V)	CD-37 3897
X144		7 43 51	-38 07 06	5	15.92	1.49	1.48		29.36	-2.93	(M1V)
X149	94	7 46 49	-38 08 50	15	9.46*	0.43*	0.42		29.27	-5.04	(F5V)	CD-37 3902
X151		7 43 06	-38 09 19	3	15.34	1.39	1.38	X	29.65	-2.73	(M0V)
X152		7 45 22	-38 09 51	39	13.21	0.98	0.97		28.52	-4.49	(K3V)
X156	57	7 45 15	-38 11 50	3	11.00	0.56	0.55	X	30.31	-3.38	(F8V)	CD-37 3862
X157	233	7 43 43	-38 12 14	10	6.35*	-0.09*	-0.10		29.19	-6.51	B9Vsp	HD 62712
X160		7 47 04	-38 12 31	10	16.32	1.56	1.55		29.38	-2.93	(M3V)
X173		7 43 52	-38 16 20	20	14.89	1.50	1.49		29.58	-3.15	(M1V)
X177		7 48 15	-38 22 35	48	11.29	0.61	0.60		30.27	-3.32	(G0V)
X181		7 43 58	-38 27 48	25	13.55	1.11	1.10	X	29.61	-3.21	(K4V)
X187		7 45 50	-38 33 55	38	12.58	0.84	0.83		29.81	-3.31	(K0V)
X188		7 44 25	-38 35 49	22	10.95*	0.61*	0.60	X	30.09	-3.64	(G0V)

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