Table 4: X-ray spectral parameters of the Cygnus OB2  OB-type stars.
Src. Optical Parameters $\chi_\nu^2$ Pile-up $N_{\rm H}$[ $\times 10^{22}$] [cm-2] kT1 kT2 Abundance Flux [10-13]
# Hanson# S.T.   (%) WABS ABSORI [keV] [keV] [$Z_\odot$] [erg s-1 cm-2]
60b 304 B5 Ie 1.4 $\sim $18 2.15 $\pm$ 0.15 0.87 $\pm$ 0.12 0.63 $\pm$ 0.03 1.56 $\pm$ 0.11 0.43 $\pm$ 0.04 $\rm 235.4^{255.4}_{201.7}$
133 339 O8.5 V 1.1 no 0.24 $\pm$ 0.18 - 1.53 $\pm$ 0.68 - (0.3) $\rm0.11^{0.19}_{0.07}$
253 378 B0 V 1.0 no 3.57 $\pm$ 0.09 - 0.43 $\pm$ 0.15 - (0.3) $\rm 2.00^{2.21}_{1.42}$
315 390 O8 V 0.8 no 3.30 $\pm$ 0.08 - 0.44 $\pm$ 0.10 - 0.15 $\pm$ 0.09 $\rm0.64^{0.73}_{0.51}$
433 417 O4 III(f) 1.5 $\lesssim$2 2.30 $\pm$ 0.07 - 0.39 $\pm$ 0.06 1.94 $\pm$ 0.73 0.60 $\pm$ 0.34 $\rm 42.1^{45.3}_{34.6}$
456 421 O9.5 V 1.4 no 1.45 $\pm$ 0.08 - 1.71 $\pm$ 1.02 - (0.30) 1.06 0.881.09
488b 431 O5 If 1.3 $\sim $12 2.09 $\pm$ 0.07 - 0.79 $\pm$ 0.05 2.82 $\pm$ 0.61 0.65 $\pm$ 0.10 $\rm 72.6^{75.5}_{67.5}$
530 448 O6 V 1.4 no 1.97 $\pm$ 0.34 - 0.65 $\pm$ 0.20 - (0.1) $\rm 1.18^{1.39}_{0.96}$
537 455 O8 V 1.1 no 2.19 $\pm$ 0.07 - 0.61 $\pm$ 0.17 - (0.1) $\rm 1.20^{1.28}_{1.07}$
544 457 O3 If 1.3 $\lesssim$2 2.12 $\pm$ 0.06 0.56 $\pm$ 0.09 0.39 $\pm$ 0.14 1.32 $\pm$ 0.19 0.97 $\pm$ 0.3 $\rm 88.8^{98.6}_{77.5}$
562 462 O6.5 II 1.0 no 2.52 $\pm$ 0.48 - 0.40 $\pm$ 0.12 - 0.14 $\pm$ 0.1 $\rm 8.45^{9.1}_{6.4}$
568a 465 O6If + O5.5III(f) 1.4 $\sim $15 2.94 $\pm$ 1.25 - 0.91 $\pm$ 0.05 2.64 $\pm$ 0.07 0.52 $\pm$ 0.07 $\rm 61.3^{64.9}_{57.1}$
584 470 O9.5 V 0.8 no 1.85 $\pm$ 0.07 - 0.44 $\pm$ 0.18 - (0.3) $\rm 3.49^{3.98}_{2.89}$
597 473 O8.5 V 1.0 no 1.88 $\pm$ 0.09 - 0.30 $\pm$ 0.22 - 1.07 $\rm 3.00^{3.78}_{2.38}$
615 480 O7.5 V 1.0 no 2.73 $\pm$ 0.06 - 0.50 $\pm$ 0.17 - (0.1) $\rm 4.01^{4.43}_{3.42}$
625 483 O5 If 1.0 no 1.00 $\pm$ 0.08 - 0.55 $\pm$ 0.06 - 0.60 $\pm$ 0.21 $\rm 99.4^{107.3}_{86.4}$
626 485 O8 V 1.1 no 1.65 $\pm$ 0.04 - 0.88 $\pm$ 0.23 - (0.1) $\rm0.38^{0.53}_{0.21}$
686 507 O8.5 V 1.1 no 2.39 $\pm$ 0.08 - 0.35 $\pm$ 0.11 - (0.3) $\rm 4.16^{5.04}_{3.28}$
729a 516 O5.5 V(f) 1.1 $\lesssim$4 0.81 $\pm$ 0.05 0.51 $\pm$ 0.32 1.98 $\pm$ 0.12 - 0.38 $\pm$ 0.09 $\rm 11.7^{12.4}_{10.1}$
779 534 O7.5 V 1.2 no 1.16 $\pm$ 0.03 - 2.28 $\pm$ 0.55 - (0.1) $\rm 6.05^{7.74}_{4.91}$
817 556 B1 Ib 0.9 no 1.57 $\pm$ 0.08 - 0.18 $\pm$ 0.07 - (0.3) $\rm 1.20^{1.53}_{0.94}$
881 588 B0 V 0.9 no 1.84 $\pm$ 0.05 - 0.42 $\pm$ 0.20 - (0.3) $\rm0.81^{1.02}_{0.71}$
895 601 O9.5 III 1.0 no 1.98 $\pm$ 0.07 - 0.38 $\pm$ 0.21 - (0.3) $\rm0.72^{0.92}_{0.50}$
971 642 B1 III 0.9 no 1.73 $\pm$ 0.05 - 0.96 $\pm$ 0.45 - (0.3) $\rm0.14^{0.30}_{0.09}$
979 646 B1.5 V +? 1.5 no 2.90 $\pm$ 1.24 - 1.92 $\pm$ 1.01 - (0.3) $\rm0.22^{0.63}_{0.29}$
1001 696 O9.5 V 0.8 no 0.71 $\pm$ 0.02 - 0.54 $\pm$ 0.17 - (0.3) $\rm0.71^{0.83}_{0.42}$
Notes: (1) Abundance values in parenthesis indicate cases for which abundances were fixed in the spectral fit (see text), (2) Absorption-corrected fluxes are calculated in the 0.5-8.0 keV energy range (3) Three bright sources, #60, #488, and #568, suffer pile-up, and we extracted the spectra from annular rings (see Sect. 3.2) that exclude the central parts of the PSFs. a The 6.4+6.7 keV FeK$_\alpha $ complex is observed; b The Fe I 6.4 keV line is not detected, but the 6.7 keV seems to be present.

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