@article{ShenarOskinovaHamannetal.2015, author = {Shenar, Tomer and Oskinova, Lida and Hamann, Wolf-Rainer and Corcoran, Michael F. and Moffat, Anthony F. J. and Pablo, Herbert and Richardson, Noel D. and Waldron, Wayne L. and Huenemoerder, David P. and Maiz Apellaniz, Jesus and Nichols, Joy S. and Todt, Helge Tobias and Naze, Yael and Hoffman, Jennifer L. and Pollock, Andy M. T. and Negueruela, Ignacio}, title = {A coordinated X-Ray and optical campaign of the nearest massive eclipsing binary, delta ORIONIS Aa. IV. A multiwavelength, non-lte spectroscopic analysis}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {809}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/809/2/135}, pages = {20}, year = {2015}, abstract = {Eclipsing systems of massive stars allow one to explore the properties of their components in great detail. We perform a multi-wavelength, non-LTE analysis of the three components of the massive multiple system delta Ori A, focusing on the fundamental stellar properties, stellar winds, and X-ray characteristics of the system. The primary's distance-independent parameters turn out to be characteristic for its spectral type (O9.5 II), but usage of the Hipparcos parallax yields surprisingly low values for the mass, radius, and luminosity. Consistent values follow only if delta Ori lies at about twice the Hipparcos distance, in the vicinity of the sigma-Orionis cluster. The primary and tertiary dominate the spectrum and leave the secondary only marginally detectable. We estimate the V-band magnitude difference between primary and secondary to be Delta V approximate to 2.(m)8. The inferred parameters suggest that the secondary is an early B-type dwarf (approximate to B1 V), while the tertiary is an early B-type subgiant (approximate to B0 IV). We find evidence for rapid turbulent velocities (similar to 200 km s(-1)) and wind inhomogeneities, partially optically thick, in the primary's wind. The bulk of the X-ray emission likely emerges from the primary's stellar wind (logL(X)/L-Bol approximate to -6.85), initiating close to the stellar surface at R-0 similar to 1.1 R-*. Accounting for clumping, the mass-loss rate of the primary is found to be log (M) over dot approximate to -6.4 (M-circle dot yr(-1))., which agrees with hydrodynamic predictions, and provides a consistent picture along the X-ray, UV, optical, and radio spectral domains.}, language = {en} } @article{CorcoranNicholsPabloetal.2015, author = {Corcoran, Michael F. and Nichols, Joy S. and Pablo, Herbert and Shenar, Tomer and Pollock, Andy M. T. and Waldron, Wayne L. and Moffat, Anthony F. J. and Richardson, Noel D. and Russell, Christopher M. P. and Hamaguchi, Kenji and Huenemoerder, David P. and Oskinova, Lida and Hamann, Wolf-Rainer and Naze, Yael and Ignace, Richard and Evans, Nancy Remage and Lomax, Jamie R. and Hoffman, Jennifer L. and Gayley, Kenneth and Owocki, Stanley P. and Leutenegger, Maurice and Gull, Theodore R. and Hole, Karen Tabetha and Lauer, Jennifer and Iping, Rosina C.}, title = {A coordinated X-Ray and optical campaign of the nearest massive eclipsing binary, delta ORIONIS Aa. I. Overview of thr X-Ray spectrum}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {809}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/809/2/132}, pages = {15}, year = {2015}, abstract = {We present an overview of four deep phase-constrained Chandra HETGS X-ray observations of delta Ori A. Delta Ori A is actually a triple system that includes the nearest massive eclipsing spectroscopic binary, delta Ori Aa, the only such object that can be observed with little phase-smearing with the Chandra gratings. Since the fainter star, delta Ori Aa2, has a much lower X-ray luminosity than the brighter primary (delta Ori Aa1), delta Ori Aa provides a unique system with which to test the spatial distribution of the X-ray emitting gas around delta Ori Aa1 via occultation by the photosphere of, and wind cavity around, the X-ray dark secondary. Here we discuss the X-ray spectrum and X-ray line profiles for the combined observation, having an exposure time of nearly 500 ks and covering nearly the entire binary orbit. The companion papers discuss the X-ray variability seen in the Chandra spectra, present new space-based photometry and ground-based radial velocities obtained simultaneously with the X-ray data to better constrain the system parameters, and model the effects of X-rays on the optical and UV spectra. We find that the X-ray emission is dominated by embedded wind shock emission from star Aa1, with little contribution from the tertiary star Ab or the shocked gas produced by the collision of the wind of Aa1 against the surface of Aa2. We find a similar temperature distribution to previous X-ray spectrum analyses. We also show that the line half-widths are about 0.3-0.5 times the terminal velocity of the wind of star Aa1. We find a strong anti-correlation between line widths and the line excitation energy, which suggests that longer-wavelength, lower-temperature lines form farther out in the wind. Our analysis also indicates that the ratio of the intensities of the strong and weak lines of Fe XVII and Ne X are inconsistent with model predictions, which may be an effect of resonance scattering.}, language = {en} } @article{TownsleyBroosCorcoranetal.2011, author = {Townsley, Leisa K. and Broos, Patrick S. and Corcoran, Michael F. and Feigelson, Eric D. and Gagne, Marc and Montmerle, Thierry and Oey, M. S. and Smith, Nathan and Garmire, Gordon P. and Getman, Konstantin V. and Povich, Matthew S. and Evans, Nancy Remage and Naze, Yael and Parkin, E. R. and Preibisch, Thomas and Wang, Junfeng and Wou, Scott J. and Chu, You-Hua and Cohen, David H. and Gruendl, Robert A. and Hamaguchi, Kenji and King, Robert R. and Mac Low, Mordecai-Mark and McCaughrean, Mark J. and Moffat, Anthony F. J. and Oskinova, Lida and Pittard, Julian M. and Stassun, Keivan G. and Ud-Doula, Asif and Walborn, Nolan R. and Waldron, Wayne L. and Churchwell, Ed and Nictiols, J. S. and Owocki, Stanley P. and Schulz, Norbert S.}, title = {An introduction to the chandra carina complex project}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series}, volume = {194}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0067-0049}, doi = {10.1088/0067-0049/194/1/1}, pages = {28}, year = {2011}, abstract = {The Great Nebula in Carina provides an exceptional view into the violent massive star formation and feedback that typifies giant H II regions and starburst galaxies. We have mapped the Carina star-forming complex in X-rays, using archival Chandra data and a mosaic of 20 new 60 ks pointings using the Chandra X-ray Observatory's Advanced CCD Imaging Spectrometer, as a testbed for understanding recent and ongoing star formation and to probe Carina's regions of bright diffuse X-ray emission. This study has yielded a catalog of properties of > 14,000 X-ray point sources;> 9800 of them have multiwavelength counterparts. Using Chandra's unsurpassed X-ray spatial resolution, we have separated these point sources from the extensive, spatially-complex diffuse emission that pervades the region; X-ray properties of this diffuse emission suggest that it traces feedback from Carina's massive stars. In this introductory paper, we motivate the survey design, describe the Chandra observations, and present some simple results, providing a foundation for the 15 papers that follow in this special issue and that present detailed catalogs, methods, and science results.}, language = {en} } @article{ParkinBroosTownsleyetal.2011, author = {Parkin, E. R. and Broos, Patrick S. and Townsley, L. K. and Pittard, J. M. and Moffat, Anthony F. J. and Naze, Y. and Rauw, G. and Oskinova, Lida and Waldron, W. L.}, title = {X-RAY EMISSION FROM THE DOUBLE-BINARY OB-STAR SYSTEM QZ CAR (HD 93206)}, series = {ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES}, volume = {194}, journal = {ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES}, number = {1}, publisher = {IOP PUBLISHING LTD}, address = {BRISTOL}, issn = {0067-0049}, doi = {10.1088/0067-0049/194/1/8}, pages = {11}, year = {2011}, abstract = {X-ray observations of the double-binary OB-star system QZ Car (HD 93206) obtained with the Chandra X-ray Observatory over a period of roughly 2 years are presented. The respective orbits of systems A (O9.7 I+b2 v, P-A = 21 days) and B (O8 III+o9 v, P-B = 6 days) are reasonably well sampled by the observations, allowing the origin of the X-ray emission to be examined in detail. The X-ray spectra can be well fitted by an attenuated three-temperature thermal plasma model, characterized by cool, moderate, and hot plasma components at kT similar or equal to 0.2, 0.7, and 2 keV, respectively, and a circumstellar absorption of similar or equal to 0.2 x 10(22) cm(-2). Although the hot plasma component could be indicating the presence of wind-wind collision shocks in the system, the model fluxes calculated from spectral fits, with an average value of similar or equal to 7x10(-13) erg s(-1) cm(-2), do not show a clear correlation with the orbits of the two constituent binaries. A semi-analytical model of QZ Car reveals that a stable momentum balance may not be established in either system A or B. Yet, despite this, system B is expected to produce an observed X-ray flux well in excess of the observations. If one considers the wind of the O8 III star to be disrupted by mass transfer, the model and observations are in far better agreement, which lends support to the previous suggestion of mass transfer in the O8 III+o9 v binary. We conclude that the X-ray emission from QZ Car can be reasonably well accounted for by a combination of contributions mainly from the single stars and the mutual wind-wind collision between systems A and B.}, language = {en} } @article{NazeBroosOskinovaetal.2011, author = {Naze, Y. and Broos, Patrick S. and Oskinova, Lida and Townsley, L. K. and Cohen, David H. and Corcoran, M. F. and Evans, N. R. and Gagne, M. and Moffat, Anthony F. J. and Pittard, J. M. and Rauw, G. and Ud-Doula, A. and Walborn, N. R.}, title = {GLOBAL X-RAY PROPERTIES OF THE O AND B STARS IN CARINA}, series = {ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES}, volume = {194}, journal = {ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES}, number = {1}, publisher = {IOP PUBLISHING LTD}, address = {BRISTOL}, issn = {0067-0049}, doi = {10.1088/0067-0049/194/1/7}, pages = {20}, year = {2011}, 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 L-X-L-BOL 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(L-X/L-BOL) is -7.26 for single objects, with a dispersion of only 0.21 dex. 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 L-X-L-BOL 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 L-X-L-BOL ratio in the medium (1.0-2.5 keV) 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.}, language = {en} } @article{GagneFehonSavoyetal.2011, author = {Gagne, Marc and Fehon, Garrett and Savoy, Michael R. and Cohen, David H. and Townsley, Leisa K. and Broos, Patrick S. and Povich, Matthew S. and Corcoran, Michael F. and Walborn, Nolan R. and Evans, Nancy Remage and Moffat, Anthony F. J. and Naze, Yael and Oskinova, Lida}, title = {Carina ob stars: x-ray signatures of wind shocks and magnetic FIELDS}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series}, volume = {194}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Supplement series}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0067-0049}, doi = {10.1088/0067-0049/194/1/5}, pages = {26}, year = {2011}, abstract = {The Chandra Carina Complex contains 200 known O- and B-type stars. The Chandra survey detected 68 of the 70 O stars and 61 of 127 known B0-B3 stars. We have assembled a publicly available optical/X-ray database to identify OB stars that depart from the canonical L-X/L-bol relation or whose average X-ray temperatures exceed 1 keV. Among the single O stars with high kT we identify two candidate magnetically confined wind shock sources: Tr16-22, O8.5 V, and LS 1865, O8.5 V((f)). The O4 III(fc) star HD 93250 exhibits strong, hard, variable X-rays, suggesting that it may be a massive binary with a period of > 30 days. The visual O2 If* binary HD 93129A shows soft 0.6 keV and hard 1.9 keV emission components, suggesting embedded wind shocks close to the O2 If* Aa primary and colliding wind shocks between Aa and Ab. Of the 11 known O-type spectroscopic binaries, the long orbital-period systems HD 93343, HD 93403, and QZ Car have higher shock temperatures than short-period systems such as HD 93205 and FO 15. Although the X-rays from most B stars may be produced in the coronae of unseen, low-mass pre-main-sequence companions, a dozen B stars with high L-X cannot be explained by a distribution of unseen companions. One of these, SS73 24 in the Treasure Chest cluster, is a new candidate Herbig Be star.}, language = {en} }