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J/ApJS/194/7      X-ray properties of O and B stars in Carina      (Naze+, 2011)

Global X-ray properties of the O and B stars in Carina. Naze Y., Broos P.S., Oskinova L., Townsley L.K., Cohen D., Corcoran M.F., Evans N.R., Gagne M., Moffat A.F.J., Pittard J.M., Rauw G., ud-Doula A., Walborn N.R. <Astrophys. J. Suppl. Ser., 194, 7 (2011)> =2011ApJS..194....7N
ADC_Keywords: Stars, OB ; X-ray sources Keywords: ISM: individual objects (Carina nebula) - stars: massive; X-rays: stars Abstract: The key empirical property of the X-ray emission from O stars is a strong correlation between the bolometric and X-ray luminosities. In the framework of the Chandra Carina Complex Project, 129 O and B stars have been detected as X-ray sources; 78 of those, all with spectral type earlier than B3, have enough counts for at least a rough X-ray spectral characterization. This leads to an estimate of the LX-LBOL ratio for an exceptional number of 60 O stars belonging to the same region and triples the number of Carina massive stars studied spectroscopically in X-rays. The derived log(LX/LBOL) is 7.26 for single objects, with a dispersion of only 0.21dex. Using the properties of hot massive stars listed in the literature, we compare the X-ray luminosities of different types of objects. In the case of O stars, the LX-LBOL ratios are similar for bright and faint objects, as well as for stars of different luminosity classes or spectral types. Binaries appear only slightly harder and slightly more luminous in X-rays than single objects; the differences are not formally significant (at the 1% level), except for the LX-LBOL ratio in the medium (1.0-2.5keV) energy band. Weak-wind objects have similar X-ray luminosities but they display slightly softer spectra compared with "normal" O stars with the same bolometric luminosity. Discarding three overluminous objects, we find a very shallow trend of harder emission in brighter objects. The properties of the few B stars bright enough to yield some spectral information appear to be different overall (constant X-ray luminosities, harder spectra), hinting that another mechanism for producing X-rays, besides wind shocks, might be at work. However, it must be stressed that the earliest and X-ray brightest among these few detected objects are similar to the latest O stars, suggesting a possibly smooth transition between the two processes. Description: File ob78_2.dat contains 64 X-ray spectral parameters used for the 78 O- and early-B stars with determined spectral types and more than 50 net counts in the Chandra Carina Complex Project (Townsley+, 2011ApJS..194....1G). Lbol values are from Povich et al. (2011, Cat. J/ApJS/194/6). Spectral types from Gagne et al. (2001, Cat. J/ApJS/194/5). See also Broos et al, (2001, Cat. J/ApJS/194/2) File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 251 77 *Best-fit results for hot stars associated with X-ray sources with >50 counts table2.fits 2880 10 FITS version of table2 table3.dat 123 77 *Summary of sources' properties table3.fits 2880 9 FITS version of table3 table5.dat 104 51 Properties of X-ray sources with <50 counts table6.dat 94 71 Properties of the undetected OB stars ob78_2.dat 1021 78 Model properties ob78_2.fits 2880 28 FITS version of ob78_2.dat
Note on table2.dat: Source 104557.13-595643.1 (Cl* Trumpler 16 MJ 640), for which bolometric luminosity and its interstellar column could not be derived, was omitted in the table. Note on table3.dat : The X-ray luminosities have been corrected for the interstellar absorption only (see the text).
See also: B/chandra : The Chandra Archive Log (CXC, 1999-) J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011) J/ApJS/194/4 : A Naive Bayes source classifier for X-ray sources (Broos+ 2011) J/ApJS/194/5 : Carina OB stars in the CCCP project (Gagne+, 2011) J/ApJS/194/6 : Candidate X-ray emitting OB stars in Carina (Povich+, 2011) J/ApJS/194/9 : X-ray star clusters in the Carina complex (Feigelson+, 2011) J/ApJS/194/10 : NIR properties of YSO in the CCCP (Preibisch+, 2011) J/ApJS/194/11 : Chandra study of Trumpler 15 in Carina (Wang+, 2011) J/ApJS/194/12 : Trumpler 16 in the CCCP (Wolk+, 2011) J/ApJS/194/14 : A Pan-Carina YSO catalog (Povich+, 2011) J/ApJS/194/15 : CCCP: Carina's diffuse X-ray emission (Townsley+, 2011) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 18 A18 --- CXOGNC CXOGNCJ designation ( 20- 29 F10.6 deg RAdeg Right ascension in decimal degrees (J2000) 31- 40 F10.6 deg DEdeg Declination in decimal degrees (J2000) 43- 53 E11.6 ct Nct ? Net Counts in the 0.5-8keV band 56- 66 E11.6 ct b_Nct ? Lower 1-sigma limit for Nct (2) 69- 79 E11.6 ct B_Nct ? Upper 1-sigma limit for Nct (2) 82- 92 E11.6 ph/cm2/s Flux ? Photon flux (G1) 94-101 F8.6 --- chi2r ? Reduced chi2 103-105 I3 --- dof ? Degree Of Freedom 107-111 F5.3 10+22cm-2 NH(ISM) ? Interstellar hydrogen column density 113-119 F7.4 [cm-2] logNH1 ? Circumstellar Hydrogen column density 121-127 F7.4 [cm-2] b_logNH1 ? Lower 1-sigma limit for logNH1 (2) 129-135 F7.4 [cm-2] B_logNH1 ? Upper 1-sigma limit for logNH1 (2) 137-145 F9.6 keV kT1 ? First thermal component kT temperature 147-154 F8.6 keV b_kT1 ? Lower 1-sigma limit for kT1 (2) 156-163 F8.6 keV B_kT1 ? Upper 1-sigma limit for kT1 (2) 165-171 F7.4 [---] logEM1 ? First thermal component emission measure 173-179 F7.4 [---] b_logEM1 ? Lower 1-sigma limit for logEM1 (2) 181-187 F7.4 [---] B_logEM1 ? Upper 1-sigma limit for logEM1 (2) 189-197 F9.6 keV kT2 ? Second thermal component kT temperature 199-206 F8.6 keV b_kT2 ? Lower 1-sigma limit for kT2 (2) 208-214 F7.5 keV B_kT2 ? Upper 1-sigma limit for kT2 (2) 216-222 F7.4 [---] logEM2 ? Second thermal component emission measure 224-230 F7.4 [---] b_logEM2 ? Lower 1-sigma limit for logEM2 (2) 232-238 F7.4 [---] B_logEM2 ? Upper 1-sigma limit for logEM2 (2) 241-251 E11.6 mW/m2 FluxT ? Total band (0.5-10keV) observed flux
Note (2): Lower and upper limits of the confidence interval (with 68% confidence for counts and 90% confidence for the spectral parameters and fluxes).
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 18 A18 --- CXOGNC CXOGNCJ designation ( 20- 41 A22 --- Name Other name 43- 67 A25 --- SpType MK spectral type 69 A1 --- bin? [Y] Binarity status 71- 74 F4.2 [Lsun] log(Lbol) Bolometric luminosity 76- 80 F5.2 [10-7W] logLx Total (0.5-10keV) band X-ray luminosity 82- 86 F5.2 [10-7W] logLxS Soft (0.1-1keV) band X-ray luminosity 88- 92 F5.2 [10-7W] logLxM Medium (1-2.5keV) band X-ray luminosity 94- 98 F5.2 [10-7W] logLxH Hard (2.5-10keV) band X-ray luminosity 100-104 F5.2 [---] log(Lx/bol) Total X-ray band to bolometric luminosity ratio 106-110 F5.2 [---] log(LxS/bol) Soft X-ray band to bolometric luminosity ratio 112-116 F5.2 [---] log(LxM/bol) Medium X-ray band to bolometric luminosity ratio 118-123 F6.2 [---] log(LxH/bol) Hard X-ray band to bolometric luminosity ratio
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 18 A18 --- CXOGNC CXOGNCJ designation ( 20- 41 A22 --- Name Other name 43- 57 A15 --- SpType MK spectral type 59 A1 --- bin? [Y] Binarity status 61- 64 F4.2 [Lsun] logLbol Bolometric luminosity 66- 69 F4.1 ct Nct ? Net counts in the 0.5-8keV band 71- 74 F4.1 ct B_Nct ? Upper 68% confidence interval for Nct 76- 79 F4.1 ct b_Nct ? Lower 68% confidence interval for Nct 81- 87 E7.3 ph/cm2/s Flux ? Photon flux (net counts divided by the mean effective area and the exposure time) 89- 92 F4.2 keV Emed ? Median energy of the recorded counts 94- 98 F5.2 [10-7W] logLx Absorption-corrected total (0.5-10keV) X-ray band luminosity 100-104 F5.2 [---] log(Lx/bol) Total X-ray band to bolometric luminosity ratio
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Right ascension (J2000) 4- 5 I2 min RAm Right ascension (J2000) 7- 11 F5.2 s RAs Right ascension (J2000) 13 A1 --- DE- Declination sign (J2000) 14- 15 I2 deg DEd Declination (J2000) 17- 18 I2 arcmin DEm Declination (J2000) 20- 23 F4.1 arcsec DEs Declination (J2000) 25- 46 A22 --- Name Name 49- 61 A13 --- SpType MK spectral type 63 A1 --- bin? [Y] Binary status 65- 68 F4.2 [Lsun] logLbol Bolometric luminosity 70- 73 F4.1 ct Nct ? Upper Limit on net counts in 0.5-8keV band 75- 81 E7.3 ph/cm2/s Flux ? Upper Limit on photon flux (G1) 83- 87 F5.2 [10-7W] logLx ? Upper Limit on absorption-corrected X-ray luminosity 89- 94 F6.2 [---] log(Lx/bol) ? Upper Limit on total X-ray band to bolometric luminosity ratio
Byte-by-byte Description of file: ob78_2.dat
Bytes Format Units Label Explanations
1- 28 A28 --- SpModel AE XSPEC model name 30- 37 F8.6 --- chi2r ? Best-fit reduced chi squared 39- 47 F9.6 [cm-2] logNH1 Hydrogen column density from XSPEC 49- 56 F8.5 [cm-2] b_logNH1 ?=- lower 1-sigma bound for NH1 58- 66 F9.6 [cm-2] B_logNH1 ?=- upper 1-sigma bound for NH1 68- 72 F5.2 [cm-2] logNH1_CI ?=- Circumstellar hydrogen column density from XSPEC 74- 77 F4.2 [cm-2] ElogNH1CI ?=- Error on logNH1_CI (upper limit) 79- 82 F4.2 [cm-2] elogNH1CI ?=- Error on logNH1_CI (lower limit) 84- 93 A10 --- f_logNH1 NH1 flag from XSPEC 95-102 F8.6 keV kT1 ?=- First thermal component kT temperature from XSPEC 104-111 F8.6 keV b_kT1 ?=- lower 1-sigma bound for kT1 113-120 F8.6 keV B_kT1 ?=- upper 1-sigma bound for kT1 122-126 F5.2 keV kT1_CI ?=- Circumstellar first thermal component kT temperature from XSPEC 128-132 F5.2 keV EkT1CI ?=- Error on kT1_CI (upper limit) 134-137 F4.2 keV ekT1CI ?=- Error on kT1_CI (lower limit) 139-148 A10 --- f_kT1 kT1 flags from XSPEC 150-158 F9.6 keV kT2 ?=- Second thermal component kT temperature from XSPEC 160-167 F8.6 keV b_kT2 ?=- Lower 1-sigma bound for kT2 169-176 F8.6 keV B_kT2 ?=- Upper 1-sigma bound for kT2 178-182 F5.2 keV kT2_CI ?=- CI second kT value from XSPEC 184-187 F4.2 keV EkT2CI ?=- Error on kT2_CI (upper limit) 189-192 F4.2 keV ekT2CI ?=- Error on kT2_CI (lower limit) 194-203 A10 --- f_kT2 kT2 flags from XSPEC 205-213 F9.6 [cm-5] logNORM1 ?=- First thermal component NORM parameter from XSPEC 215-224 F10.6 [cm-5] b_logNORM1 ?=- lower 1-sigma bound for logNORM1 226-234 F9.6 [cm-5] B_logNORM1 ?=- upper 1-sigma bound for logNORM1 236-240 F5.2 [cm-5] logNORM1_CI ?=- Circumstellar first thermal component NORM parameter from XSPEC 242-245 F4.2 [cm-5] ElogNORM1CI ?=- Error on NORM1_CI (upper limit) 247-250 F4.2 [cm-5] elogNORM1CI ?=- Error on NORM1_CI (lower limit) 252-255 F4.1 [cm-5] logEM1_CI ?=- Circumstellar first thermal component emission measure from XSPEC 257-260 F4.2 [cm-5] ElogEM1CI ?=- Error on EM1_CI (upper limit) 262-265 F4.2 [cm-5] elogEM1CI ?=- Error on EM1_CI (lower limit) 267-276 A10 --- f_logNORM1 NORM1 flag from XSPEC 278-286 F9.6 [cm-5] logNORM2 ?=- Second thermal component NORM parameter from XSPEC 288-297 F10.6 [cm-5] b_logNORM2 ?=- Lower 1-sigma bound for logNORM2 299-307 F9.6 [cm-5] B_logNORM2 ?=- Upper 1-sigma bound for logNORM2 309-313 F5.2 [cm-5] logNORM2_CI ?=- Circumstellar second thermal component NORM parameter from XSPEC 315-318 F4.2 [cm-5] ElogNORM2CI ?=- Error on NORM2_CI (upper limit) 320-323 F4.2 [cm-5] elogNORM2CI ?=- Error on NORM2_CI (lower limit) 325-328 F4.1 [cm-5] logEM2_CI ?=- Circumstellar second thermal component emission measure from XSPEC 330-333 F4.2 [cm-5] ElogEM2CI ?=- Error on EM2_CI (upper limit) 335-338 F4.2 [cm-5] elogEM2CI ?=- Error on EM2_CI (lower limit) 340-349 A10 --- f_logNORM2 NORM2 flags from XSPEC 351-361 E11.6 mW/m2 FH2 ? Flux in 0.5-2.0keV 363-373 E11.6 mW/m2 E_FH2 ? Flux in 0.5-2.0keV, 90% 2-sided limit 375-385 E11.6 mW/m2 e_FH2 ? Flux in 0.5-2.0keV, 90% 2-sided limit 387-397 E11.6 mW/m2 F28 ? Flux in 2.0-8.0keV 399-409 E11.6 mW/m2 E_F28 ? Flux in 2.0-8.0keV; 90% 2-sided limit 411-421 E11.6 mW/m2 e_F28 ? Flux in 2.0-8.0keV; 90% 2-sided limit 423-433 E11.6 mW/m2 FH8 ? Flux in 0.5-8.0keV 435-445 E11.6 mW/m2 E_FH8 ? Flux in 0.5-8.0keV; 90% 2-sided limit 447-457 E11.6 mW/m2 e_FH8 ? Flux in 0.5-8.0keV; 90% 2-sided limit 459-469 E11.6 mW/m2 FSO ? Flux in 0.5-1.0keV 471-481 E11.6 mW/m2 E_FSO ? Flux in 0.5-1.0keV; 90% 2-sided limit 483-493 E11.6 mW/m2 e_FSO ? Flux in 0.5-1.0keV; 90% 2-sided limit 495-505 E11.6 mW/m2 FME ? Flux in 1.0-2.5keV 507-517 E11.6 mW/m2 E_FME ? Flux in 1.0-2.5keV; 90% 2-sided limit 519-529 E11.6 mW/m2 e_FME ? Flux in 1.0-2.5keV; 90% 2-sided limit 531-541 E11.6 mW/m2 FHA ? Flux in 2.5-10.0keV 543-553 E11.6 mW/m2 E_FHA ? Flux in 2.5-10.0keV; 90% 2-sided limit 555-565 E11.6 mW/m2 e_FHA ? Flux in 2.5-10.0keV; 90% 2-sided limit 567-577 E11.6 mW/m2 FTO ? Flux in 0.5-10.0keV 579-589 E11.6 mW/m2 E_FTO ? Flux in 0.5-10.0keV; 90% 2-sided limit 591-601 E11.6 mW/m2 e_FTO ? Flux in 0.5-10.0keV; 90% 2-sided limit 603-613 E11.6 mW/m2 F1H2 ? Flux in 0.5-2.0keV, norm2=0 615-625 E11.6 mW/m2 F128 ? Flux in 2.0-8.0keV, norm2=0 627-637 E11.6 mW/m2 F1H8 ? Flux in 0.5-8.0keV, norm2=0 639-649 E11.6 mW/m2 F1SO ? Flux in 0.5-1.0keV, norm2=0 651-661 E11.6 mW/m2 F1ME ? Flux in 1.0-2.5keV, norm2=0 663-673 E11.6 mW/m2 F1HA ? Flux in 2.5-10.0keV, norm2=0 675-685 E11.6 mW/m2 F1TO ? Flux in 0.5-10.0keV, norm2=0 687-697 E11.6 mW/m2 F1CH2 ? Flux in 0.5-2.0keV, norm2=0,NHISM=0 699-709 E11.6 mW/m2 F1C28 ? Flux in 2.0-8.0keV, norm2=0,NHISM=0 711-721 E11.6 mW/m2 F1CH8 ? Flux in 0.5-8.0keV, norm2=0,NHISM=0 723-733 E11.6 mW/m2 F1CSO ? Flux in 0.5-1.0keV, norm2=0,NHISM=0 735-745 E11.6 mW/m2 F1CME ? Flux in 1.0-2.5keV, norm2=0,NHISM=0 747-757 E11.6 mW/m2 F1CHA ? Flux in 2.5-10.0keV, norm2=0,NHISM=0 759-769 E11.6 mW/m2 F1CTO ? Flux in 0.5-10.0keV, norm2=0,NHISM=0 771-781 E11.6 mW/m2 F2H2 ? Flux in 0.5-2.0keV, norm1=0 783-793 E11.6 mW/m2 F228 ? Flux in 2.0-8.0keV, norm1=0 795-805 E11.6 mW/m2 F2H8 ? Flux in 0.5-8.0keV, norm1=0 807-817 E11.6 mW/m2 F2SO ? Flux in 0.5-1.0keV, norm1=0 819-829 E11.6 mW/m2 F2ME ? Flux in 1.0-2.5keV, norm1=0 831-841 E11.6 mW/m2 F2HA ? Flux in 2.5-10.0keV, norm1=0 843-853 E11.6 mW/m2 F2TO ? Flux in 0.5-10.0keV, norm1=0 855-865 E11.6 mW/m2 F2CH2 ? Flux in 0.5-2.0keV, norm1=0,NHISM=0 867-877 E11.6 mW/m2 F2C28 ? Flux in 2.0-8.0keV, norm1=0,NHISM=0 879-889 E11.6 mW/m2 F2CH8 ? Flux in 0.5-8.0keV, norm1=0,NHISM=0 891-901 E11.6 mW/m2 F2CSO ? Flux in 0.5-1.0keV, norm1=0,NHISM=0 903-913 E11.6 mW/m2 F2CME ? Flux in 1.0-2.5keV, norm1=0,NHISM=0 915-925 E11.6 mW/m2 F2CHA ? Flux in 2.5-10.0keV, norm1=0,NHISM=0 927-937 E11.6 mW/m2 F2CTO ? Flux in 0.5-10.0keV, norm1=0,NHISM=0 939-949 E11.6 mW/m2 FCH2 ? Flux in 0.5-2.0keV, NHISM=0 951-961 E11.6 mW/m2 FC28 ? Flux in 2.0-8.0keV, NHISM=0 963-973 E11.6 mW/m2 FCH8 ? Flux in 0.5-8.0keV, NHISM=0 975-985 E11.6 mW/m2 FCSO ? Flux in 0.5-1.0keV, NHISM=0 987-997 E11.6 mW/m2 FCME ? Flux in 1.0-2.5keV, NHISM=0 999-1009 E11.6 mW/m2 FCHA ? Flux in 2.5-10.0keV, NHISM=0 1011-1021 E11.6 mW/m2 FCTO ? Flux in 0.5-10.0keV, NHISM=0
Global notes: Note (G1): net counts divided by the mean effective area and the exposure time.
Acknowledgements: Marc Gagne, mgagne(at) Leisa Townsley, townsley(at) Pat Broos, patb(at) Matt Povich, povich(at) Yael Naze, naze(at) References: Townsley et al. CCCP introduction 2011ApJS..194....1T Broos et al. CCCP catalog Cat. J/ApJS/194/2 Getman et al. Contamination in X-ray studies 2011ApJS..194....3G Broos et al. Source classifier Cat. J/ApJS/194/4 Gagne et al. O and B stars Cat. J/ApJS/194/5 Povich et al. Cand. X-ray emitting OB stars Cat. J/ApJS/194/6 Naze et al. O and B stars X-ray properties Cat. J/ApJS/194/7 Parkin et al. QZ Car (HD 93206) 2011ApJS..194....8P Feigelson et al. X-ray star clusters Cat. J/ApJS/194/9 Preibisch et al. NIR properties of YSO Cat. J/ApJS/194/10 Wang et al. Trumpler 15 Cat. J/ApJS/194/11 Wolk et al. Trumpler 16 Cat. J/ApJS/194/12 Povich et al. Pan-Carina YSO catalog Cat. J/ApJS/194/14 Evans et al. Companions of B stars in Tr 16 2011ApJS..194...13E Townsley et al. Diffuse X-ray emission Cat. J/ApJS/194/15 Townsley et al. Comparison of diffuse emission 2011ApJS..194...16T
(End) Marc Gagne [West Chester Univ., USA], Patricia Vannier [CDS] 05-May-2011
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