Astrophysics and Astronomy Commons^™

Thermal Conductance Of A Two-Channel Kondo Model, C P. Moca, A Roman, D C. Marinescu

Publications

A theory of thermal transport in a two-channel Kondo system, such as the one formed by a small quantum dot coupled to two leads and to a larger dot, is formulated. The interplay of the two screening constants allow an exploration of the Fermi liquid and non-Fermi liquid regimes. By using analytical, as well as numerical, renormalization group methods, we study the temperature dependence of the thermal conductance and the Lorentz number. We find that in the low-temperature limit, the Lorentz number attains its universal value, irrespective of the nature of the ground state.

Propagation Of Solar Energetic Particles In Three-Dimensional Interplanetary Magnetic Fields: In View Of Characteristics Of Sources, H. Q. He, Gang Qin, Ming Zhang

Aerospace, Physics, and Space Science Faculty Publications

In this paper, a model of solar energetic particle (SEP) propagation in the three-dimensional Parker interplanetary magnetic field is calculated numerically. We study the effects of the different aspects of particle sources on the solar surface, which include the source location, coverage of latitude and longitude, and spatial distribution of source particle intensity, on propagation of SEPs with both parallel and perpendicular diffusion. We compute the particle flux and anisotropy profiles at different observation locations in the heliosphere. From our calculations, we find that the observation location relative to the latitudinal and longitudinal coverage of particle source has the strongest …

Search For Gravitational Wave Bursts From Six Magnetars, J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, T. Accadia, F. Acernese, C. Adams, R. Adhikari, C. Affeldt, B. Allen, G. S. Allen, E. Amador Ceron, D. Amariutei, R. S. Amin, S. B. Anderson, W. G. Anderson, F. Antonucci, K. Arai, M. A. Arain, M. C. Araya, S. M. Aston, P. Astone, D. Atkinson, P. Aufmuth, C. Aulbert, B. E. Aylott, S. Babak, P. Baker, G. Ballardin, S. Ballmer, D. Barker, Tiffany Z. Summerscales

Faculty Publications

Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects are characterized by repeated and sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures and excitation of non-radial modes which would emit gravitational waves (GWs). We present the results of a search for GW bursts from six galactic magnetars that is sensitive to neutron star f-modes, thought to be the most efficient GW emitting oscillatory modes in compact stars. One of them, SGR 0501+4516, is likely 1kpc from Earth, an order of magnitude closer …

Search For Gravitational Wave Bursts From Six Magnetars, J. Abadie, B. P. Abbott, R. Abbott, M. Abernathy, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya D. Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects are characterized by repeated and sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures and excitation of non-radial modes which would emit gravitational waves (GWs). We present the results of a search for GW bursts from six galactic magnetars that is sensitive to neutron star f-modes, thought to be the most efficient GW emitting oscillatory modes in compact stars. One of them, SGR 0501+4516, is likely 1kpc from Earth, an order of magnitude closer …

The Cataclysmic Variable Sdss J1507+52: An Eclipsing Period Bouncer In The Galactic Halo, Helena Uthas, Christian Knigge, Knox S. Long, Joseph Patterson, John Thorstensen

Dartmouth Scholarship

SDSS J1507+52 is an eclipsing cataclysmic variable (CV) consisting of a cool, non-radially pulsating white dwarf and an unusually small substellar secondary. The system has a high space velocity and a very short orbital period of about 67 min, well below the usual minimum period for CVs. To explain the existence of this peculiar system, two theories have been proposed. One suggests that SDSS J1507+52 was formed from a detached white dwarf-brown dwarf binary. The other theory proposes that the system is a member of the Galactic halo population.

Here, we present the ultraviolet (UV) spectroscopy of SDSS J1507+52 obtained …

A Spitzer Transmission Spectrum For The Exoplanet Gj 436b, Evidence For Stellar Variability, And Constraints On Dayside Flux Variations, Heather Knutson, Nikku Madhusudhan, Nicolas B. Cowan, Jessie L. Christiansen, Eric Agol, Drake Deming, Jean-Michel Désert, David Charbonneau, Gregory W. Henry, Derek Homeier, Jonathan Langton, Gregory Laughlin, Sara Seager

Information Systems and Engineering Management Research Publications

In this paper, we describe a uniform analysis of eight transits and eleven secondary eclipses of the extrasolar planet GJ 436b obtained in the 3.6, 4.5, and 8.0 μm bands using the IRAC instrument on the Spitzer Space Telescope between UT 2007 June 29 and UT 2009 February 4. We find that the best-fit transit depths for visits in the same bandpass can vary by as much as 8% of the total (4.7σ significance) from one epoch to the next. Although we cannot entirely rule out residual detector effects or a time-varying, high-altitude cloud layer in the planet's atmosphere as …

Temporal And Spatial Aspects Of Gas Release During The 2010 Apparition Of Comet 103p/Hartley 2, M. Mumma, B. Bonev, G. Villanueva, L. Paganini, M. Disanti, E. Gibb, J. Keane, K. Meech, G. Blake, R. Ellis, M. Lippi, H. Boehnhardt, K. Magee-Sauer

Physics Faculty Works

We report measurements of eight primary volatiles (H2O, HCN, CH4, C2H6, CH3OH, C2H2, H2CO, and NH3) and two product species (OH and NH2) in comet 103P/Hartley 2 using high-dispersion infrared spectroscopy. We quantified the long- and short-term behavior of volatile release over a three-month interval that encompassed the comet's close approach to Earth, its perihelion passage, and flyby of the comet by the Deep Impact spacecraft during the EPOXI mission. We present production rates for individual species, their mixing ratios relative to water, and their spatial distributions in the coma on multiple dates. The production rates for water, ethane, HCN, …

Arcade 2 Observations Of Galactic Radio Emission, A. Kogut, D. J. Fixsen, S. M. Levin, M. Limon, P. M. Lubin, P. Mirel, M. Seiffert, Jack Singal, T. Villela, E. Wollack, C. A. Wuensche

Physics Faculty Publications

We use absolutely calibrated data from the ARCADE 2 flight in 2006 July to model Galactic emission at frequencies 3, 8, and 10 GHz. The spatial structure in the data is consistent with a superposition of free–free and synchrotron emission. Emission with spatial morphology traced by the Haslam 408 MHz survey has spectral index βsynch = −2.5±0.1, with free–free emission contributing 0.10±0.01 of the total Galactic plane emission in the lowest ARCADE 2 band at 3.15 GHz. We estimate the total Galactic emission toward the polar caps using either a simple plane-parallel model with csc |b| dependence or a model …

Interpretation Of The Arcade 2 Absolute Sky Brightness Measurement, M. Seiffert, D. J. Fixsen, A. Kogut, S. M. Levin, M. Limon, P. M. Lubin, P. Mirel, Jack Singal, T. Villela, E. Wollack, C. A. Wuensche

Physics Faculty Publications

We use absolutely calibrated data between 3 and 90 GHz from the 2006 balloon flight of the ARCADE 2 instrument, along with previous measurements at other frequencies, to constrain models of extragalactic emission. Such emission is a combination of the cosmic microwave background (CMB) monopole, Galactic foreground emission, the integrated contribution of radio emission from external galaxies, any spectral distortions present in the CMB, and any other extragalactic source. After removal of estimates of foreground emission from our own Galaxy, and an estimated contribution of external galaxies, we present fits to a combination of the flat-spectrum CMB and potential spectral …

Arcade 2 Measurement Of The Absolute Sky Brightness At 3-90 Ghz, D. J. Fixsen, A. Kogut, S. Levin, M. Limon, P. Lubin, P. Mirel, M. Seiffert, Jack Singal, E. Wollack, T. Villela, C. A. Wuensche

Physics Faculty Publications

The ARCADE 2 instrument has measured the absolute temperature of the sky at frequencies 3, 8, 10, 30, and 90 GHz, using an open-aperture cryogenic instrument observing at balloon altitudes with no emissive windows between the beam-forming optics and the sky. An external blackbody calibrator provides an in situ reference. Systematic errors were greatly reduced by using differential radiometers and cooling all critical components to physical temperatures approximating the cosmic microwave background (CMB) temperature. A linear model is used to compare the output of each radiometer to a set of thermometers on the instrument. Small corrections are made for the …

On The Origin Of Fluctuations In The Cusp Diamagnetic Cavity, K. Nykyri, A. Otto, E. Adamson, A. Tjulin

Publications

We have analyzed Cluster magnetic field and plasma data during high‐altitude cusp crossing on 14 February 2003. Cluster encountered a diamagnetic cavity (DMC) during northward interplanetary magnetic field (IMF) conditions, and as IMF rotated southward, the spacecraft reencountered the cavity more at the sunward side. The DMC is characterized by a high level of magnetic field fluctuations and high‐energy electrons and protons. Ultralow‐frequency turbulence has been suggested as a mechanism to accelerate particles in DMC. We demonstrate in this paper for the first time that many of the low‐frequency fluctuations in the cavity are back and forth motion of the …

Search For Gravitational Waves From Binary Black Hole Inspiral Merger And Ringdown, J. Abadie, B. P. Abbott, Matthew Benacquista, Teviet Creighton, Mario C. Diaz, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

We present the first modeled search for gravitational waves using the complete binary black-hole gravitational waveform from inspiral through the merger and ringdown for binaries with negligible component spin. We searched approximately 2 years of LIGO data, taken between November 2005 and September 2007, for systems with component masses of 1-99Mȯ and total masses of 25-100Mȯ. We did not detect any plausible gravitational-wave signals but we do place upper limits on the merger rate of binary black holes as a function of the component masses in this range. We constrain the rate of mergers for 19Mȯ≤m1, m 2≤28Mȯ binary black-hole …

Ro-Vibrational Co Detected In The Β Pictoris Circumstellar Disk, Matthew R. Troutman, Kenneth H. Hinkle, Joan R. Najita, Terrence W. Rettig, Sean D. Brittain

Publications

We present high-resolution near-infrared spectra of β Pictoris—a nearby young star with a debris disk. Fundamental low-J CO absorption lines are detected and strict upper limits are placed on the flux of v = 2–1 low-J CO emission lines. The limit on the UV fluorescent emission flux in the v = 2–1 lines is used to place a tight constraint on the inner extent of the CO gas. Assuming Hi is the primary collision partner, the sub-thermal population of the low-J v = 0 rotational levels constrains the density of the gas in the disk to nH = (2.5+7.1 −1.2)×105 …

The Vlt Lbg Redshift Survey I: Clustering And Dynamics Of ≈ 1000 Galaxies At Z ≈ 3⋆, R. M. Bielby, T. Shanks, P. M. Weilbacher, L. Infante, N. H.M. Crighton, C. Bornancini, N. Bouché, P. Héraudeau, D. G. Lambas, James D. Lowenthal, D. Minniti, N. Padilla, P. Petitjean, T. Theuns

Astronomy: Faculty Publications

We present the initial imaging and spectroscopic data acquired as part of the Very Large Telescope (VLT) VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five ≈36 × 36 arcmin fields centred on bright z > 3 quasi-stellar objects (QSOs), allowing ≈210002 < z < 3.5 galaxy candidates to be selected using the Lyman-break technique. We performed spectroscopic follow-up using VLT VIMOS, measuring redshifts for 1020 z > 2 Lyman-break galaxies and 10 z > 2 QSOs from a total of 19 VIMOS pointings. From the galaxy spectra, we observe a 625 ± 510kms velocity offset between the interstellar absorption and Lyman α emission-line redshifts, consistent with previous results. Using the photometric and spectroscopic catalogues, we have analysed the galaxy clustering at z≈ 3. The angular correlation …

A Layer Correlation Technique For Pion Energy Calibration At The 2004 Atlas Combined Beam Test, E. Abat, J M. Abdallah, T N. Addy, P Adragna, M Aharrouche, A Ahmad, T Pa Akesson, M Aleksa, C Alexa, K Anderson, A Andreazza, F Anghinolfi, A Antonaki, G Arabize, E Arik, T Atkinson, J Baines, O K. Baker, D Banfi, S Baron, Roberto Petti, Et. Al.

Faculty Publications

A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 …

Time-Dependent Behavior Of Linear Polarization In Unresolved Photospheres, With Applications For The Hanle Effect., Richard Ignace, K. Hole, J. Cassinelli, G. Henson

ETSU Faculty Works

Aims: This paper extends previous studies in modeling time varying linear polarization due to axisymmetric magnetic fields in rotating stars. We use the Hanle effect to predict variations in net line polarization, and use geometric arguments to generalize these results to linear polarization due to other mechanisms. Methods: Building on the work of Lopez Ariste et al., we use simple analytic models of rotating stars that are symmetric except for an axisymmetric magnetic field to predict the polarization lightcurve due to the Hanle effect. We highlight the effects for the variable line polarization as a function of viewing inclination and …

Analysis Of The 2008 Flare Of Markarian 421 Flare With Veritas, Casey Allard

Physics

A theoretical light curve model is fit to an observed short term flare of Markarian (Mrk) 421 in the very high energy spectrum. The flare is characterized by its measured light curve from the Very Energetic Radiation Imaging telescope Array System (VERITAS). The flare we analyzed occurred in May 2008. We successfully fit a theoretical model to the Mrk 421 data light curve. The data appears to agree with the Wagner [1] and Salvati [2] models. These models appear to fit both broad and sharp flaring regions found in the measured light curve. Furthermore the Wagner model is used to …

On Detection Of The Stochastic Gravitational-Wave Background Using The Parkes Pulsar Timing Array, D. R.B. Yardley, W. A. Coles, G. B. Hobbs, J. P.W. Verbiest, R. N. Manchester, W. Van Straten, Fredrick A. Jenet, M. Bailes, N. D.R. Bhat

Physics & Astronomy Faculty Publications

We search for the signature of an isotropic stochastic gravitational-wave background in pulsar timing observations using a frequency-domain correlation technique. These observations, which span roughly 12yr, were obtained with the 64-m Parkes radio telescope augmented by public domain observations from the Arecibo Observatory. A wide range of signal processing issues unique to pulsar timing and not previously presented in the literature are discussed. These include the effects of quadratic removal, irregular sampling and variable errors which exacerbate the spectral leakage inherent in estimating the steep red spectrum of the gravitational-wave background. These observations are found to be consistent with the …

Systematics Of Black Hole Binary Inspiral Kicks And The Slowness Approximation, Richard H. Price, Gaurav Khanna, Scott A. Hughes

Physics & Astronomy Faculty Publications

During the inspiral and merger of black holes, the interaction of gravitational wave multipoles carries linear momentum away, thereby providing an astrophysically important recoil, or “kick” to the system and to the final black hole remnant. It has been found that linear momentum during the last stage (quasinormal ringing) of the collapse tends to provide an “antikick” that in some cases cancels almost all the kick from the earlier (quasicircular inspiral) emission. We show here that this cancellation is not due to peculiarities of gravitational waves, black holes, or interacting multipoles, but simply to the fact that the rotating flux …

Ab Initio Description Of Nonlinear Dynamics Of Coupled Microdisk Resonators With Application To Self-Trapping Dynamics, Hamidreza Ramezani, Tsampikos Kottos, V. Shuvayev, L. Deych

Physics & Astronomy Faculty Publications

An ab initio approach is used to describe the time evolution of the amplitudes of whispering gallery modes in a system of coupled microdisk resonators with Kerr nonlinearity. It is shown that this system demonstrates a transition between Josephson-like nonlinear oscillations and self-trapping behavior. Manifestation of this transition in the dynamics of radiative losses is studied.

A Survey Of Molecular Hydrogen In The Crab Nebula, E. D. Loh, J. A. Baldwin, Z. K. Curtis, Gary J. Ferland, C. R. O'Dell, A. C. Fabian, Philippe Salomé

Physics and Astronomy Faculty Publications

We have carried out a near-infrared, narrowband imaging survey of the Crab Nebula, in the H₂ 2.12 μm and Brγ 2.17 μm lines, using the Spartan Infrared camera on the SOAR Telescope. Over a 2.8 × 5'.1 area that encompasses about 2/3 of the full visible extent of the Crab, we detect 55 knots that emit strongly in the H₂ line. We catalog the observed properties of these knots. We show that they are in or next to the filaments that are seen in optical-passband emission lines. Comparison to Hubble Space Telescope [S …

Generation Of Coherent Structures After Cosmic Inflation, Marcelo Gleiser, Noah Graham, Nikitas Stamatopoulos

Dartmouth Scholarship

We investigate the nonlinear dynamics of hybrid inflation models, which are characterized by two real scalar fields interacting quadratically. We start by solving numerically the coupled Klein-Gordon equations in static Minkowski spacetime, searching for possible coherent structures. We find long-lived, localized configurations, which we identify as a new kind of oscillon. We demonstrate that these two-field oscillons allow for “excited” states with much longer lifetimes than those found in previous studies of single-field oscillons. We then solve the coupled field equations in an expanding Friedmann-Robertson-Walker spacetime, finding that as the field responsible for inflating the Universe rolls down to oscillate …

The Effect Of Tidal Disruptions On Giant Stars In The Galactic Center, Brian B. Geiss

Undergraduate Honors Thesis Collection

Recent observational data suggest the depletion of late-type giant stars in the inner most region of the Galactive Nucleus. Using dynamically evolving Fokker-Planck models of the Galactic Nucleus, we have followed in detail the stellar distribution as it evolves through the postmain-sequence phases. Of particular interest was the effect of stellar collisions and tidal disruptions by the central massive black hole on post main sequence stars as they expand in size. B y modeling tidal disruptions and stellar collisions, we have found that there should be a significant depletion of the giant stars in the innermost regions of the nucleus. …

Broad Lyα Emission From Three Nearby Bl Lacertae Objects, John T. Stocke, Charles W. Danforth, Eric S. Perlman

Aerospace, Physics, and Space Science Faculty Publications

We present far-UV HST/COS spectra of four nearby BLLac objects. BLLac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Lyα emission in HST/COS spectra of Mrk421 (z = 0.030) and PKS2005-489 (z = 0.071) as well as an archival HST/GHRS observation of Mrk501 (z = 0.0337). Archival HST/STIS observations of PKS2155-304 (z = 0.116) show no Lyα emission to a very low upper limit. Using the assumption that the broad-line region …

Sdss J162520.29+120308.7 – A New Su Ursae Majoris Star In The Period Gap, A. Olech, E. De Miguel, M. Otulakowska, J. R. Thorstensen

Dartmouth Scholarship

We report results of an extensive world-wide observing campaign devoted to the recently discovered dwarf nova SDSS J162520.29+120308.7 (SDSS J1625). The data were obtained during the July 2010 eruption of the star and in August and September 2010 when the object was in quiescence.

Polarization Of The Charge-Exchange X-Rays Induced In The Heliosphere, M. Gacesa, H.-R. Müller, R. Côté, V. Kharchenko

Dartmouth Scholarship

We report results of a theoretical investigation of polarization of the X-ray emissions induced in charge-exchange collisions of fully stripped solar wind ions C6+and O8+ with the heliospheric hydrogen atoms. The polarization of X-ray emissions has been computed for line-of-sight observations within the ecliptic plane as a function of solar wind ion velocities, including a range of velocities corresponding to the slow and fast solar wind, and Coronal Mass Ejections. To determine the variability of polarization of heliospheric X-ray emissions, the polarization has been computed for solar minimum conditions with self-consistent parameters of the solar wind plasma and heliospheric gas …

Uv, Optical, And Infrared Imaging Of The Interacting Galaxy Arp 107 And Its Star Forming Regions., Ryen C. Lapham

Undergraduate Honors Theses

In this study we present GALEX UV, Sloan Digital Sky Survey, and Spitzer infrared imaging, along with an optical Hα map of the interacting galaxy pair Arp 107. IRAF photometry was used to analyze 29 star forming regions identified in previous work done with Spitzer colors. In this paper further analysis of the clumps of newly formed stars was done by creating Spectral Energy Distribution plots to sort the clumps as quiescent or starbursts. Color - color plots were used to estimate the ages and extinctions of the clumps by comparing magnitudes to stellar population synthesis models. Results seem to …

Grips - Gamma-Ray Imaging, Polarimetry And Spectroscopy, Jochen Greiner, Karl Mannheim, Felix Aharonian, Marco Ajello, Lajos G. Balaz, Guido Barbiellini, Ronaldo Bellazzini, Shawn Bishop, Gennady S. Bisnoyatij-Kogan, Steven Boggs, Andrej Bykov, Guido Dicocco, Roland Diehl, Dominik Elsasser, Suzanne Foley, Claes Fransson, Neil Gehrels, Lorraine Hanlon, Dieter H. Hartmann

Publications

We propose to perform a continuously scanning all-sky survey from 200 keV to 80 MeV achieving a sensitivity which is better by a factor of 40 or more compared to the previous missions in this energy range (COMPTEL, INTEGRAL; see Fig. 1). The Gamma-Ray Imaging, Polarimetry and Spectroscopy (“GRIPS”) mission addresses fundamental questions in ESA’s Cosmic Vision plan. Among the major themes of the strategic plan, GRIPS has its focus on the evolving, vio-lent Universe, exploring a unique energy window. We propose to investigate γ-ray bursts and blazars, the mechanisms behind supernova explosions, nucleosynthesis and spallation, the enigmatic origin of …

An Introduction To The Chandra Carina Complex Project, L. K. Townsley, P. S. Broos, M. F. Corcoran, E. D. Feigelson, M. Gagné, T. Montmerle, M. S. Oey, N. Smith, G. P. Garmire, K. V. Getman, M. S. Povich, N. R. Evans, Y. Nazé, E. R. Parkin, T. Preibisch, J. Wang, S. J. Wou, Y.-H. Chu, David H. Cohen, R. A. Gruendl, K. Hamaguchi, R. R. King, M.-M. M. Low, M. J. Mccaughrean, A. F.J. Moffat, L. M. Oskinova, J. M. Pittard, K. G. Stassun, A. Ud-Doula, N. R. Walborn, W. L. Waldron, E. Churchwell, J. S. Nictiols, S. P. Owocki, N. S. Schulz

Physics & Astronomy Faculty Works

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 …

Global X-Ray Properties Of The O And B Stars In Carina, Y. Nazé, P. S. Broos, L. M. Oskinova, L. K. Townsley, David H. Cohen, M. F. Corcoran, N. R. Evans, M. Gagné, A. F.J. Moffat, J. M. Pittard, G. Rauw, A. Ud-Doula, N. R. Walborn

Physics & Astronomy Faculty Works

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 …