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Sample records for massive x-ray binary

  1. X-ray irradiation of the winds in binaries with massive components

    NASA Astrophysics Data System (ADS)

    Krtička, J.; Kubát, J.; Krtičková, I.

    2015-07-01

    Context. Binaries with hot massive components are strong X-ray sources. Besides the intrinsic X-ray emission of individual binary members originating in their winds, X-ray emission stems from the accretion on the compact companion or from wind collision. Since hot star winds are driven by the light absorption in the lines of heavier elements, wind acceleration is sensitive to the ionization state. Therefore, the over-ionization induced by external X-ray source strongly influences the winds of individual components. Aims: We studied the effect of external X-ray irradiation on hot star winds. Methods: We used our kinetic equilibrium (NLTE) wind models to estimate the influence of external X-ray ionization for different X-ray luminosities and source distances. The models are calculated for parameters typical of O stars. Results: The influence of X-rays is given by the X-ray luminosity, by the optical depth between a given point and the X-ray source, and by a distance to the X-ray source. Therefore, the results can be interpreted in the diagrams of X-ray luminosity vs. the optical depth parameter. X-rays are negligible in binaries with low X-ray luminosities or at large distances from the X-ray source. The influence of X-rays is stronger for higher X-ray luminosities and in closer proximity of the X-ray source. There is a forbidden area with high X-ray luminosities and low optical depth parameters, where the X-ray ionization leads to wind inhibition. There is excellent agreement between the positions of observed stars in these diagrams and our predictions. All wind-powered high-mass X-ray binary primaries lie outside the forbidden area. Many of them lie close to the border of the forbidden area, indicating that their X-ray luminosities are self-regulated. We discuss the implications of our work for other binary types. Conclusions: X-rays have a strong effect on the winds in binaries with hot components. The magnitude of the influence of X-rays can be estimated from the

  2. The x-ray and spectropolarimetric view of mass loss and transfer in massive binary stars

    NASA Astrophysics Data System (ADS)

    Lomax, Jamie R.

    2013-03-01

    The majority of massive stars are members of binary systems. In order to have a better understanding of their evolutionary pathways, the mass and angular momentum loss from massive binaries needs to be well understood. Self consistent explanations for their behavior need to be valid across many wavelength regimes in order to illuminate key phases of mass loss to completely determine how it affects their evolution. In this dissertation I present the results of X-ray and specropolarimetric studies on one Roche-lobe overflow binary (beta Lyr) and two colliding wind binaries (V444 Cyg and WR 140). In beta Lyr a repeatable discrepancy between the secondary eclipse in total and polarized light indicates that an accretion hot spot has formed on the edge of the disk in the system. This hot spot may also be the source of the bipolar outflows within the system. The existence of a hot spot and its relationship to bipolar outflows is important in understanding the mass transfer dynamics of Roche-lobe overflow binaries. The absorption of the 2.0 keV spectral fit component in V444 Cyg suggests that the shock has a large opening angle while analysis of the X-ray light curves places the stagnation point farther away from the O star than theoretically expected. Combining this with evidence of polarimetric variability in V444 Cyg's optical emission lines shows that the effects of radiative inhibition or braking are significant for this close binary and may be important in other colliding wind systems. Long term X-ray monitoring of the shock formed by the winds in WR 140 shows conflicting evidence for unexpected intrinsic hard X-ray emission. Spectral analysis shows that the low energy thermal tail is causing the observed higher energy emission. On the other hand, light curve analysis of the absorption feature near periastron passage suggests that there may be intrinsic hard X-ray emission from the system. WR 140's polarimetric behavior is consistent with the formation of dust near

  3. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  4. The X-ray and Spectropolarimetric View of Mass Loss and Transfer in Massive Binary Stars

    NASA Astrophysics Data System (ADS)

    Lomax, Jamie R.

    2014-01-01

    The majority of massive stars are members of binary systems. However, in order to understand their evolutionary pathways, mass and angular momentum loss from these systems needs to be well characterized. Self-consistent explanations for their behavior across many wavelength regimes need to be valid in order to illuminate key evolutionary phases. In this talk I will present the results of an X-ray and spectropolarimetric study of three key binaries: beta Lyrae, V444 Cyg, and WR 140. In beta Lyrae, I will show a repeatable discrepancy between secondary eclipse in the total and polarized light curves indicates an accretion hot spot has formed on the edge of the disk in the system. The existence of this hot spot and its relationship to bipolar outflows within the system is important in the understanding of mass transfer dynamics in Roche-lobe overflow binaries. For V444 Cyg, I will present the results of an X-ray and polarimetric monitoring campaign which indicate the effects of radiative inhibition or braking, and the Coriolis force can be significant contributors to the location and shape of the shock within colliding wind binaries. Additionally, I will present data from WR 140 that suggest unexpected intrinsic hard X-ray emission may be present at some and argue that better polarimetric monitoring of the system is needed. Continued work on these and additional objects will provide new and important constraints on the mass loss structures within binary systems. This research includes contributions from collaborators at the University of Denver, NASA/GSFC, The Universite de Liege, The University of Toledo, East Tennessee State University, The University of Leeds, ESA, Hokkai-Gakuen University, NRAO, The University of Delaware, and Vanderbilt University. Additionally, I acknowledge support from the NASA Harriett G. Jenkins Pre-doctoral Fellowship Program, Sigma Xi’s Grants-in-Aid of Research Program, and NASA ADAP award NNH12ZDA001N.

  5. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  6. A Broad-Band X-Ray Telescope spectrum of the massive X-ray binary X Persei

    NASA Technical Reports Server (NTRS)

    Schlegel, Eric M.; Serlemitsos, Peter J.; Jahoda, Keith; Marshall, Frank; Petre, Robert; Boldt, Elihu; Mushotzky, Richard; Swank, Jean; Szymkowiak, Andrew; Smale, Alan

    1993-01-01

    The Broad Band X-Ray Telescope, covering the 0.3-12 keV bandpass with moderate spectral resolution, observed the Be/X-ray binary X Per in 1990 December during the Astro-l mission on the Space Shuttle Columbia. The data obtained are the best to date to search for lines and edges. The data are well fitted by a power-law spectrum with a high-energy cutoff. A low value for the high-energy cutoff is found, implying a slightly weaker magnetic field strength for the X-ray pulsar. No iron line is present at about 6.5 keV with an equivalent width greater than 30-40 eV. The BBXRT observation corresponded to the 'off' state of X Per's recent 'phase change'.

  7. A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, Delta Orionis Aa. I. Overview of the X-Ray Spectrum

    NASA Technical Reports Server (NTRS)

    Corcoran, M. F.; Nicholas, J. S.; Pablo, H.; Shenar, T.; Pollock, A. M. T.; Waldron, W. L.; Moffat, A. F. J.; Richardson, N. D.; Russell, C. M. P.; Hamaguchi, K.; Leutenegger, M.; Gull, T. R.; Iping, R. C.

    2015-01-01

    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.

  8. A COORDINATED X-RAY AND OPTICAL CAMPAIGN OF THE NEAREST MASSIVE ECLIPSING BINARY, δ ORIONIS Aa. I. OVERVIEW OF THE X-RAY SPECTRUM

    SciTech Connect

    Corcoran, M. F.; Hamaguchi, K.; Pablo, H.; Moffat, A. F. J.; Richardson, N. D.; Shenar, T.; Oskinova, L.; Hamann, W.-R.; Waldron, W. L.; Russell, C. M. P.; Huenemoerder, D. P.; Nazé, Y.; Ignace, R.; and others

    2015-08-20

    We present an overview of four deep phase-constrained Chandra HETGS X-ray observations of δ Ori A. Delta Ori A is actually a triple system that includes the nearest massive eclipsing spectroscopic binary, δ Ori Aa, the only such object that can be observed with little phase-smearing with the Chandra gratings. Since the fainter star, δ Ori Aa2, has a much lower X-ray luminosity than the brighter primary (δ Ori Aa1), δ Ori Aa provides a unique system with which to test the spatial distribution of the X-ray emitting gas around δ 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.

  9. Stability of mass transfer from massive giants: double black hole binary formation and ultraluminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Pavlovskii, K.; Ivanova, N.; Belczynski, K.; Van, K. X.

    2017-02-01

    Mass transfer in binaries with massive donors and compact companions, when the donors rapidly evolve after their main sequence, determines the formation rates of merging double stellar-mass black hole (BH) binaries formed outside clusters. This mass transfer was previously postulated to be unstable and was expected to lead to a common envelope event. The common envelope event then ends with either the merger of the two stars or formation of a binary that eventually may become a merging double BH. We revisit the stability of this mass transfer and find an unanticipated third outcome: for a large range of binary orbital separations, this mass transfer is stable. This newly found stability allows us to reconcile the empirical rate obtained by LIGO, 9-240 Gpc-3 yr-1, with the theoretical rate for double BH binary mergers predicted by population synthesis studies by excluding a channel that predicts a merger rate above 1000 Gpc-3 yr-1. Furthermore, the stability of the mass transfer leads to the formation of ultraluminous X-ray sources. The theoretically predicted formation rates of bright ultraluminous X-ray sources powered by a stellar-mass BH are high enough to explain the number of observed bright ultraluminous X-ray sources.

  10. UV observations of x ray binaries

    NASA Technical Reports Server (NTRS)

    Raymond, John C.

    1990-01-01

    IUE (International Ultraviolet Explorer) has observed both high and low mass x ray binaries throughout its life. The UV spectra of high mass systems reveal the nature of the massive companion star and the effects of the x ray illumination of the stellar wind. In loss mass systems, the x ray illuminated disk or companion star dominates the UV light. System parameters and the characteristics of the accretion disk can be inferred.

  11. A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, Delta Orionis Aa. II. X-Ray Variability

    NASA Technical Reports Server (NTRS)

    Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Naze, Y.; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.; Hamaguchi, K.; Gull, T.

    2015-01-01

    We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the delta Ori Aa binary system. The four observations, obtained with Chandra ACIS (Advanced CCD Imaging Spectrometer) HETGS (High Energy Transmission Grating), have a total exposure time approximately equal to 479 kiloseconds and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5-25 angstroms is confirmed, with a maximum amplitude of about plus or minus15 percent within a single approximately equal to125 kiloseconds observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 kiloseconds contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S (sub XV), Si (sub XIII), and Ne (sub IX). For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at phi = 0.0 when the secondary delta Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind-wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability.

  12. A Coordinated X-Ray and Optical Campaign of the Nearby Massive Binary Sigma Orionis Aa. II; X-Ray Variability

    NASA Technical Reports Server (NTRS)

    Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Naze, Y; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.; Richardson, N. D.; Pablo, H.; Evans, N. R.; Hamaguchi, K.; Gull, T.; Hamann, W.-R.; Oskinova, L.; Ignace, R.; Hoffman, Jennifer L.; Hole, K. T.; Lomax, J. R.

    2015-01-01

    We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution gratings spectral dataset of the Sigma Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of approximately 479 kiloseconds and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range 5-25 angstroms is confirmed, with maximum amplitude of about plus or minus 15 percent within a single approximately 125 kiloseconds observation. Periods of 4.76 days and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in flux level throughout the 9-day observational campaign. Using 40 kiloseconds contiguous spectra derived from the original observations, we investigate variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S XV, Si XIII, and Ne IX. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at phi equals 0.0 when the secondary Aa2 is at inferior conjunction. We use the results of an SPH radiative transfer code model, customized for this project, to relate the presence of a low density cavity in the primary stellar wind embedded shock that is associated with the secondary star to the emission line width variability.

  13. Polarization from Scattering in X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Kallman, T.

    2009-01-01

    A paradox of X-ray binaries is that their strong X-ray flux ionizes much nearby low density gas, making it difficult to observe. Polarization can reveal gas which is fully ionized and can provide new insight into X-ray binary environments. In this talk I will present models for the scattering and polarization in X-ray binaries, adopting gas parameters which are chosen according to current ideas about these systems. These include stellar winds from a massive companion, X-ray induced disk winds, and the photospheres of a disk or binary companion.

  14. How Massive are the Heaviest Black Holes in X-ray Binaries? Exploring IC 10 X-1 and its Kind.

    NASA Astrophysics Data System (ADS)

    Laycock, Silas; Maccarone, Tom; Steiner, James F.; Christodoulou, Dimitris; Yang, Jun; Binder, Breanna A.; Cappallo, Rigel

    2016-01-01

    Black hole X-ray binaries represent a unique probe of stellar evolution and the most extreme physical conditions found in nature. The X-ray binary IC 10 X-1 occupies an important niche as a link between BH-XRBs and Ultra Luminous X-ray Sources (ULX) due to its intermediate luminosity (10^38 erg/s), and role as a central exemplar of the association of between low metallicity galaxies and maximum BH mass.The most secure and direct dynamical evidence for any BH mass comes from the radial velocity (RV) curve coupled with eclipse timing measurements. We phase-connected X-ray timing data accumulated over a decade with Chandra/XMM, with the optical RV curve, revealing a surprizing simultenaity of mid X-ray eclipse and the maximum blueshift velocity of He II emission lines. Our interpretation is that the optical emission lines originate in a shadowed sector of the WR star's stellar wind which escapes X-ray ionization by the compact object. The RV shifts are therefore a projection effect of the stellar wind, and unrelated to the system's mass function which becomes completely unknown. Chandra, XMM and NuStar datasets present a complex picture of radiative transfer through a photo-ionized wind. A search for the orbital period derivative (P-dot) by X-ray timing offers additonal insights, and we present a simulation for the feasibility of constraining P-dot via optical means.This is a substantial change to our understanding of IC 10 X-1, and with similar results reported for its "near twin" NGC 300 X-1, adds new a dimension to the facinating question of the maximum mass for stellar BHs.

  15. UNDERSTANDING THE UNUSUAL X-RAY EMISSION PROPERTIES OF THE MASSIVE, CLOSE BINARY WR 20a: A HIGH ENERGY WINDOW INTO THE STELLAR WIND INITIATION REGION

    SciTech Connect

    Montes, Gabriela; Ramirez-Ruiz, Enrico; De Colle, Fabio; Strickler, Rachel

    2013-11-10

    The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf-Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit.

  16. Understanding the Unusual X-Ray Emission Properties of the Massive, Close Binary WR 20a: A High Energy Window into the Stellar Wind Initiation Region

    NASA Astrophysics Data System (ADS)

    Montes, Gabriela; Ramirez-Ruiz, Enrico; De Colle, Fabio; Strickler, Rachel

    2013-11-01

    The problem of explaining the X-ray emission properties of the massive, close binary WR 20a is discussed. Located near the cluster core of Westerlund 2, WR 20a is composed of two nearly identical Wolf-Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days. Although Chandra observations were taken during the secondary optical eclipse, the X-ray light curve shows no signs of a flux decrement. In fact, WR 20a appears slightly more X-ray luminous and softer during the optical eclipse, opposite to what has been observed in other binary systems. To aid in our interpretation of the data, we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal which includes radiative cooling and a radiative acceleration force term. It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated. Consequently, WR 20a serves as a critical test-case for how radiatively driven stellar winds are initiated and how they interact. Our models not only procure a robust description of current Chandra data, which cover the orbital phases between 0.3 and 0.6, but also provide detailed predictions over the entire orbit.

  17. The X-ray light curve of the massive colliding wind Wolf-Rayet + O binary WR 21a

    NASA Astrophysics Data System (ADS)

    Gosset, Eric; Nazé, Yaël

    2016-05-01

    Our dedicated XMM-Newton monitoring, as well as archival Chandra and Swift datasets, were used to examine the behaviour of the WN5h+O3V binary WR 21a at high energies. For most of the orbit, the X-ray emission exhibits few variations. However, an increase in strength of the emission is seen before periastron, following a 1 /D relative trend, where D is the separation between both components. This increase is rapidly followed by a decline due to strong absorption as the Wolf-Rayet (WR) comes in front. The fitted local absorption value appears to be coherent with a mass-loss rate of about 1 × 10-5 M⊙ yr-1 for the WR component. However, absorption is not the only parameter affecting the X-ray emission at periastron as even the hard X-ray emission decreases, suggesting a possible collapse of the colliding wind region near to or onto the photosphere of the companion just before or at periastron. An eclipse may appear as another potential scenario, but it would be in apparent contradiction with several lines of evidence, notably the width of the dip in the X-ray light curve and the absence of variations in the UV light curve. Afterwards, the emission slowly recovers, with a strong hysteresis effect. The observed behaviour is compatible with predictions from general wind-wind collision models although the absorption increase is too shallow. Based on observations collected at ESO as well as with Swift, Chandra, and the ESA science mission XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).

  18. Thermal Disk Winds in X-Ray Binaries: Realistic Heating and Cooling Rates Give Rise to Slow, but Massive, Outflows

    NASA Astrophysics Data System (ADS)

    Higginbottom, N.; Proga, D.; Knigge, C.; Long, K. S.

    2017-02-01

    A number of X-ray binaries exhibit clear evidence for the presence of disk winds in the high/soft state. A promising driving mechanism for these outflows is mass loss driven by the thermal expansion of X-ray heated material in the outer disk atmosphere. Higginbottom & Proga recently demonstrated that the properties of thermally driven winds depend critically on the shape of the thermal equilibrium curve, since this determines the thermal stability of the irradiated material. For a given spectral energy distribution, the thermal equilibrium curve depends on an exact balance between the various heating and cooling mechanisms at work. Most previous work on thermally driven disk winds relied on an analytical approximation to these rates. Here, we use the photoionization code cloudy to generate realistic heating and cooling rates which we then use in a 2.5D hydrodynamic model computed in ZEUS to simulate thermal winds in a typical black hole X-ray binary. We find that these heating and cooling rates produce a significantly more complex thermal equilibrium curve, with dramatically different stability properties. The resulting flow, calculated in the optically thin limit, is qualitatively different from flows calculated using approximate analytical rates. Specifically, our thermal disk wind is much denser and slower, with a mass-loss rate that is a factor of two higher and characteristic velocities that are a factor of three lower. The low velocity of the flow—{v}\\max ≃ 200 km s‑1—may be difficult to reconcile with observations. However, the high mass-loss rate—15 × the accretion rate—is promising, since it has the potential to destabilize the disk. Thermally driven disk winds may therefore provide a mechanism for state changes.

  19. X-Ray Background from Early Binaries

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-11-01

    What impact did X-rays from the first binary star systems have on the universe around them? A new study suggests this radiation may have played an important role during the reionization of our universe.Ionizing the UniverseDuring the period of reionization, the universe reverted from being neutral (as it was during recombination, the previous period)to once again being ionized plasma a state it has remained in since then. This transition, which occurred between 150 million and one billion years after the Big Bang (redshift of 6 z 20), was caused by the formation of the first objects energetic enough to reionize the universes neutral hydrogen.ROSAT image of the soft X-ray background throughout the universe. The different colors represent different energy bands: 0.25 keV (red), 0.75 keV (green), 1.5 keV (blue). [NASA/ROSAT Project]Understanding this time period in particular, determining what sources caused the reionization, and what the properties were of the gas strewn throughout the universe during this time is necessary for us to be able to correctly interpret cosmological observations.Conveniently, the universe has provided us with an interesting clue: the large-scale, diffuse X-ray background we observe all around us. What produced these X-rays, and what impact did this radiation have on the intergalactic medium long ago?The First BinariesA team of scientists led by Hao Xu (UC San Diego) has suggested that the very first generation of stars might be an important contributor to these X-rays.This hypothetical first generation, Population III stars, are thought to have formed before and during reionization from large clouds of gas containing virtually no metals. Studies suggest that a large fraction of Pop III stars formed in binaries and when those stars ended their lives as black holes, ensuing accretion from their companions could produceX-ray radiation.The evolution with redshift of the mean X-ray background intensities. Each curve represents a different

  20. The X-ray binary, UW CMa

    NASA Technical Reports Server (NTRS)

    Heap, S. R.

    1982-01-01

    The UW CMa is a close, eclipsing binary composed of an O7f primary with a stron wind and a less luminous O-type companion. It was found that UW CMa a variable X-ray source, whose X-ray variations are in phase with its optical light curve. Since both components of the binary system are O stars, accretion by a compact object is ruled out as a mechanism for generating X-rays. The UW CMa represents a new class of X-ray binaries, in which X-rays result from the collision of a wind from one star with the surface or wind of the other star. It is hypothesised that the impact of a wind against a star generates a shock wave about 0.25 stellar radii above the stellar surface, and material behind the shock front, heated to bout 10 million degrees, radiates the X-ray apparent X-ray variability is due to its location between the two stars, where it undergoes eclipses. The high temperature region maintains an ionization cavity in the wind, as detected with IUE. The ionization cavity is the source of depletion of absorbing ions in the wind between the two stars.

  1. Evidence for a Neutron Star in the non-pulsating massive X-ray binary 4U2206+54

    NASA Astrophysics Data System (ADS)

    Torrejón, J. M.; Kreykenbohm, I.; Orr, A.; Titarchuk, L.; Negueruela, I.

    2004-08-01

    We present an analysis of archival RXTE and BeppoSAX data of the X-ray source 4U2206+54. For the first time, high energy data (≥30 keV) are analyzed for this source. The data are well described by comptonization models (CompTT and BMC) in which seed photons with temperatures between 1.1 keV and 1.5 keV are comptonized by a hot plasma at 50 keV thereby producing a hard tail which extends up to, at least, 100 keV. We offer a new method of identification of neutron star systems using a temperature - luminosity relation. If a given X-ray source is characterized by a low bolometric luminosity and a relatively high color blackbody temperature (>1 keV) it has necessarily to be a neutron star rather than a black hole. From these arguments it is shown that the area of the soft photon source must be small (r≈ 1 km) and that the accretion disk, if present, must be truncated very far from the compact object. Here we report on the possible existence of a cyclotron line around 30 keV. The presence of a neutron star in the system is strongly favored by the available data.

  2. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, Rosanne; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    This grant was for the study of Luminous Supersoft X-Ray Sources (SSSs). During the first year a number of projects were completed and new projects were started. The projects include: 1) Time variability of SSSs 2) SSSs in M31; 3) Binary evolution scenarios; and 4) Acquiring new data.

  3. Polarisation modulation in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ingram, Adam; Maccarone, Thomas

    2016-07-01

    X-ray polarimetry promises to provide a powerful new lever arm for studying accretion onto black holes with the next generation of X-ray telescopes. I will discuss how polarisation can be used to help constrain the physical origin of quasi-periodic oscillations (QPOs) observed in the X-ray light curves of accreting black holes. QPOs may be signatures of the frame dragging effect: in General Relativity, a spinning black hole twists up the surrounding space-time, causing vertical precession of nearby orbits. In the truncated disc / precessing inner flow model, the entire inner accretion flow precesses as a solid body causing a modulation in the X-ray flux through solid angle and Doppler effects. This model also predicts the observed polarisation of the X-ray signal to vary quasi-periodically. I will summarise our work to model the polarisation signal from a precessing accretion flow, starting with simple assumptions about the emission mechanism but taking General Relativity fully into account. We find that it should be possible to measure the predicted modulation in polarisation degree for a reasonable region of parameter space with a polarimeter capable of detecting ~60 counts per second from a bright black hole binary. I will also show that sensitivity can be greatly improved by correlating the signal with a high count rate reference band signal.

  4. Quasiperiodic Oscillations in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    van der Klis, M.; Murdin, P.

    2000-11-01

    The term quasiperiodic oscillation (QPO) is used in high-energy astrophysics for any type of non-periodic variability that is constrained to a relatively narrow range of variability frequencies. X-RAY BINARIES are systems in which a `compact object', either a BLACK HOLE or a NEUTRON STAR, orbits a normal star and captures matter from it. The matter spirals down to the compact object and heats up ...

  5. Masses and Luminosities of X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Quirrenbach, Andreas; Frink, Sabine; Tomsick, John

    2004-01-01

    Using SIM, we will perform narrow-angle observations of several X-ray binaries to determine their orbits, and we will observe about 50 X-ray binary systems in wide-angle mode to measure their distances and proper motions. Sources with mass estimates for the compact component of greater than 3 solar masses are generally called black hole candidates since this mass is above the theoretical neutron star limit. Narrow-angle observations of these sources provide a direct test of the dynamical mass estimates on which the black hole evidence is based. Better measurements of the black hole masses will provide constraints on possible evolutionary paths that lead to black hole formation. When combined with X-ray data, mass measurements may provide additional constraints on the black hole spin. Precise mass determinations of neutron star systems can address the question of whether neutron stars can be significantly more massive than 1.4 solar masses, which would eliminate soft models of the neutron star equations of state. The wide-angle observations will probe the Galactic distribution of X-ray binaries through parallaxes and proper motions. They will also eliminate the uncertainties in the luminosities of individual sources, which is currently up to a full order of magnitude. This will enable more detailed comparisons of X-ray observations to physical models such as advection-dominated accretion flows (ADAFs). We intend to carry out the following measurements: 1) Determine the orbits of two black hole candidates to measure the black hole masses; 2) Obtain precise mass measurements for two neutron star systems to constrain neutron star equations of state; 3) Determine the distances and thus luminosities of selected representatives of various classes of X-ray binaries (black hole candidates, neutron stars, jet sources); 4) In the process of distance determination, proper motions will also be measured, from which the age of the population can be estimated.

  6. Longterm lightcurves of X-ray binaries

    NASA Astrophysics Data System (ADS)

    Clarkson, William

    The X-ray Binaries (XRB) consist of a compact object and a stellar companion, which undergoes large-scale mass-loss to the compact object by virtue of the tight ( P orb usually hours-days) orbit, producing an accretion disk surrounding the compact object. The liberation of gravitational potential energy powers exotic high-energy phenomena, indeed the resulting accretion/ outflow process is among the most efficient energy-conversion machines in the universe. The Burst And Transient Source Experiment (BATSE) and RXTE All Sky Monitor (ASM) have provided remarkable X-ray lightcurves above 1.3keV for the entire sky, at near-continuous coverage, for intervals of 9 and 7 years respectively (with ~3 years' overlap). With an order of magnitude increase in sensitivity compared to previous survey instruments, these instruments have provided new insight into the high-energy behaviour of XRBs on timescales of tens to thousands of binary orbits. This thesis describes detailed examination of the long-term X-ray lightcurves of the neutron star XRB X2127+119, SMC X-1, Her X- 1, LMC X-4, Cyg X-2 and the as yet unclassified Circinus X-1, and for Cir X-1, complementary observations in the IR band. Chapters 1 & 2 introduce X-ray Binaries in general and longterm periodicities in particular. Chapter 3 introduces the longterm datasets around which this work is based, and the chosen methods of analysis of these datasets. Chapter 4 examines the burst history of the XRB X2127+119, suggesting three possible interpretations of the apparently contradictory X-ray emission from this system, including a possible confusion of two spatially distinct sources (which was later vindicated by high-resolution imaging). Chapters 5 and 6 describe the characterisation of accretion disk warping, providing observational verification of the prevailing theoretical framework for such disk-warps. Chapters 7 & 8 examine the enigmatic XRB Circinus X-1 with high-resolution IR spectroscopy (chapter 7) and the RXTE

  7. A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, δ Orionis Aa. IV. A Multiwavelength, Non-LTE Spectroscopic Analysis

    NASA Astrophysics Data System (ADS)

    Shenar, T.; Oskinova, L.; Hamann, W.-R.; Corcoran, M. F.; Moffat, A. F. J.; Pablo, H.; Richardson, N. D.; Waldron, W. L.; Huenemoerder, D. P.; Maíz Apellániz, J.; Nichols, J. S.; Todt, H.; Nazé, Y.; Hoffman, J. L.; Pollock, A. M. T.; Negueruela, I.

    2015-08-01

    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 δ 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 δ Ori lies at about twice the Hipparcos distance, in the vicinity of the σ-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 {{Δ }}V≈ 2\\buildrel{{m}}\\over{.} 8. The inferred parameters suggest that the secondary is an early B-type dwarf (≈B1 V), while the tertiary is an early B-type subgiant (≈B0 IV). We find evidence for rapid turbulent velocities (˜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 ({log}{L}{{X}}/{L}{Bol}≈ -6.85), initiating close to the stellar surface at {R}0˜ 1.1 {R}*. Accounting for clumping, the mass-loss rate of the primary is found to be {log}\\dot{M}≈ -6.4 ({M}⊙ {{yr}}-1), which agrees with hydrodynamic predictions, and provides a consistent picture along the X-ray, UV, optical, and radio spectral domains.

  8. Be/X-ray Binary Science for Future X-ray Timing Missions

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    For future missions, the Be/X-ray binary community needs to clearly define our science priorities for the future to advocate for their inclusion in future missions. In this talk, I will describe current designs for two potential future missions and Be X-ray binary science enabled by these designs. The Large Observatory For X-ray Timing (LOFT) is an X-ray timing mission selected in February 2011 for the assessment phase from the 2010 ESA M3 call for proposals. The Advanced X-ray Timing ARray (AXTAR) is a NASA explorer concept X-ray timing mission. This talk is intended to initiate discussions of our science priorities for the future.

  9. Supergiant X-Ray Binaries Observed by Suzaku

    NASA Technical Reports Server (NTRS)

    Bodaghee, A.; Tomsick, J. A.; Rodriquez, J.; Chaty, S.; Pottschmidt, K.; Walter, R.; Romano, P.

    2011-01-01

    Suzaku observations are presented for the high-mass X-ray binaries IGR 116207-5129 and IGR 117391-3021. For IGR 116207-5129, we provide the first X-ray broadband (0.5-60 keV) spectrum from which we confirm a large intrinsic column density (N(sub H) = 1.6 x 10(exp 23)/sq cm), and we constrain the cutoff energy for the first time (E(sub cut) = 19 keV). A prolonged (> 30 ks) attenuation of the X-ray flux was observed which we tentatively attribute to an eclipse of the probable neutron star by its massive companion, in a binary system with an orbital period between 4 and 9 days, and inclination angles> 50 degrees. For IGRJ17391-3021, we witnessed a transition from quiescence to a low-activity phase punctuated by weak flares whose peak luminosities in the 0.5-10keV band are only a factor of 5 times that of the pre-flare emission. These micro flares are accompanied by an increase in NH which suggests the accretion of obscuring clumps of wind. We now recognize that these low-activity epochs constitute the most common emission phase for this system, and perhaps in other supergiant fast X-ray transients (SFXTs) as well. We close with an overview of our upcoming program in which Suzaku will provide the first ever observation of an SFXT (IGRJ16479-4514) during a binary orbit enabling us to probe the accretion wind at every phase.

  10. An X-Ray Survey of Colliding Wind Binaries

    NASA Astrophysics Data System (ADS)

    Gagné, M.; Fehon, G.; Savoy, M. R.; Cartagena, C. A.; Cohen, D. H.; Owocki, S. P.

    2012-12-01

    We have compiled a list of 35 O + O binaries and 86 Wolf-Rayet (WR) binaries in the Milky Way and Magellanic clouds detected with the Chandra, XMM-Newton, and ROSAT satellites to probe the connection between their X-ray properties and their system characteristics. Of the WR binaries with published model parameters, all have log LX > 32, kT > 1 keV and log LX/Lbol > -7. The most X-ray luminous WR binaries are typically very long period systems. The WR binaries show a nearly four-order of magnitude spread in X-ray luminosity, even among among systems with very similar WR primaries. Among the O + O binaries, short-period systems have soft X-ray spectra and longer period systems show harder X-ray spectra again with a large spread in LX/Lbol.

  11. The superslow pulsation X-ray pulsars in high mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Wang, Wei

    2013-03-01

    There exists a special class of X-ray pulsars that exhibit very slow pulsation of P spin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (P spin ~ 5560 s with Ṗ spin ~ 4.9 × 10-7 s s-1) and long-term spin-up trend for 2S 0114+65 (P spin ~ 9600 s with Ṗ spin ~ -1 × 10-6 s s-1) in the last 20 years. A Be X-ray transient, SXP 1062 (P spin ~ 1062 s), also showed a fast spin-down rate of Ṗ spin ~ 3 × 10-6 s s-1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system - accreting magnetars.

  12. Discovery of X-ray pulsations from a massive star.

    PubMed

    Oskinova, Lidia M; Nazé, Yael; Todt, Helge; Huenemoerder, David P; Ignace, Richard; Hubrig, Swetlana; Hamann, Wolf-Rainer

    2014-06-03

    X-ray emission from stars much more massive than the Sun was discovered only 35 years ago. Such stars drive fast stellar winds where shocks can develop, and it is commonly assumed that the X-rays emerge from the shock-heated plasma. Many massive stars additionally pulsate. However, hitherto it was neither theoretically predicted nor observed that these pulsations would affect their X-ray emission. All X-ray pulsars known so far are associated with degenerate objects, either neutron stars or white dwarfs. Here we report the discovery of pulsating X-rays from a non-degenerate object, the massive B-type star ξ(1) CMa. This star is a variable of β Cep-type and has a strong magnetic field. Our observations with the X-ray Multi-Mirror (XMM-Newton) telescope reveal X-ray pulsations with the same period as the fundamental stellar oscillations. This discovery challenges our understanding of stellar winds from massive stars, their X-ray emission and their magnetism.

  13. Massively parallel X-ray holography

    SciTech Connect

    Spence, John C.H; Marchesini, Stefano; Boutet, Sebastien; Sakdinawat, Anne E.; Bogan, Michael J.; Bajt, Sasa; Barty, Anton; Chapman, Henry N.; Frank, Matthias; Hau-Riege, Stefan P.; Szöke, Abraham; Cui, Congwu; Shapiro, David A.; Howells, MAlcolm R.; Shaevitz, Joshua W; Lee, Joanna Y.; Hajdu, Janos; Seibert, Marvin M.

    2008-08-01

    Advances in the development of free-electron lasers offer the realistic prospect of nanoscale imaging on the timescale of atomic motions. We identify X-ray Fourier-transform holography1,2,3 as a promising but, so far, inefficient scheme to do this. We show that a uniformly redundant array4 placed next to the sample, multiplies the efficiency of X-ray Fourier transform holography by more than three orders of magnitude, approaching that of a perfect lens, and provides holographic images with both amplitude- and phase-contrast information. The experiments reported here demonstrate this concept by imaging a nano-fabricated object at a synchrotron source, and a bacterial cell with a soft-X-ray free-electron laser, where illumination by a single 15-fs pulse was successfully used in producing the holographic image. As X-ray lasers move to shorter wavelengths we expect to obtain higher spatial resolution ultrafast movies of transient states of matter

  14. Formation and Evolution of X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Fragkos, Anastasios

    X-ray binaries - mass-transferring binary stellar systems with compact object accretors - are unique astrophysical laboratories. They carry information about many complex physical processes such as star formation, compact object formation, and evolution of interacting binaries. My thesis work involves the study of the formation and evolution of Galactic and extra-galacticX-ray binaries using both detailed and realistic simulation tools, and population synthesis techniques. I applied an innovative analysis method that allows the reconstruction of the full evolutionary history of known black hole X-ray binaries back to the time of compact object formation. This analysis takes into account all the available observationally determined properties of a system, and models in detail four of its evolutionary evolutionary phases: mass transfer through the ongoing X-ray phase, tidal evolution before the onset of Roche-lobe overflow, motion through the Galactic potential after the formation of the black hole, and binary orbital dynamics at the time of core collapse. Motivated by deep extra-galactic Chandra survey observations, I worked on population synthesis models of low-mass X-ray binaries in the two elliptical galaxies NGC3379 and NGC4278. These simulations were targeted at understanding the origin of the shape and normalization of the observed X-ray luminosity functions. In a follow up study, I proposed a physically motivated prescription for the modeling of transient neutron star low-mass X-ray binary properties, such as duty cycle, outburst duration and recurrence time. This prescription enabled the direct comparison of transient low-mass X-ray binary population synthesis models to the Chandra X-ray survey of the two ellipticals NGC3379 and NGC4278. Finally, I worked on population synthesismodels of black holeX-ray binaries in the MilkyWay. This work was motivated by recent developments in observational techniques for the measurement of black hole spin magnitudes in

  15. New developments in studies of compact X-ray binaries

    NASA Technical Reports Server (NTRS)

    Grindlay, Jonathan E.

    1987-01-01

    Several recent developments, both observational and theoretical, on the study of X-ray binaries and the compact objects they contain are discussed. The recent discovery of the first binary periods for the globular cluster X-ray sources has stimulated a new model for their origin. As a variant of the 'standard' tidal capture origin model, this predicts an enhanced number of neutron stars in globular clusters. Long term timing studies of X-ray binaries may be consistent with many of these systems, primarily X-ray burst sources, being in fact hierarchical triple systems. Finally, the radio studies of Cyg X-3 and other X-ray binaries suggest that nonthermal processes are as important, energetically, as accretion processes in these systems.

  16. X-ray emission from massive stars with magnetic fields

    NASA Astrophysics Data System (ADS)

    Oskinova, L. M.; Hamann, W.-R.; Cassinelli, J. P.; Brown, J. C.; Todt, H.

    2011-12-01

    We investigate the connections between the magnetic fields and the X-ray emission from massive stars. Our study shows that the X-ray properties of known strongly magnetic stars are diverse: while some comply to the predictions of the magnetically confined wind model, others do not. We conclude that strong, hard, and variable X-ray emission may be a sufficient attribute of magnetic massive stars, but it is not a necessary one. We address the general properties of X-ray emission from ``normal'' massive stars, especially the long standing mystery about the correlations between the parameters of X-ray emission and fundamental stellar properties. The recent development in stellar structure modeling shows that small-scale surface magnetic fields may be common. We suggest a ``hybrid'' scenario which could explain the X-ray emission from massive stars by a combination of magnetic mechanisms on the surface and shocks in the stellar wind. The magnetic mechanisms and the wind shocks are triggered by convective motions in sub-photospheric layers. This scenario opens the door for a natural explanation of the well established correlation between bolometric and X-ray luminosities. Based on observations obtained with \\xmm and \\cxo.

  17. Unveiling the X-ray point source population of the Young Massive Cluster Westerlund 1

    NASA Astrophysics Data System (ADS)

    Clark, J. S.; Muno, M. P.; Negueruela, I.; Dougherty, S. M.; Crowther, P. A.; Goodwin, S. P.; de Grijs, R.

    2008-01-01

    Aims:We investigate the nature of the X-ray point source population within the Young Massive Cluster Westerlund 1. Methods: Chandra observations of 18 ks and 42 ks were used to determine the X-ray properties of emitters within Wd 1, while a comprehensive multiwavelength dataset was employed to constrain their nature. Results: We find X-ray emission from a multitude of different stellar sources within Wd 1, including both evolved high mass and low mass pre-MS stars. We attribute the X-ray emission from the high mass component to both single stars and colliding wind binaries on the basis of their observed flux and spectral properties, with binaries being systematically harder and more luminous than single stars. We are able to infer a high binary fraction for both WN (10/16) and WC stars (7/8), resulting in a combined Wolf Rayet binary fraction of ⪆70%. These represent the most stringent limits currently placed on the binary fraction of very massive (>45 M⊙) stars. We place the first observational constraints on X-ray emission from stars transitioning between the Main Sequence and Wolf Rayet phases, finding that both hot (B hypergiants) and cool (yellow hypergiants and red supergiants) spectral types appear to be intrinsically X-ray faint. The B[e] star W9 is found to be X-ray bright and shows similarities to both the X-ray binary SS433 and the Luminous Blue Variable η Carinae. Globally, we find the point source population to be systematically fainter than those found in younger massive star forming regions such as NGC 3603 and R136/30 Doradus, consistent with a loss of the most massive stars to SNe and a reduction in emissivity from the low mass pre-Main Sequence stars. No unambiguous evidence for X-ray emission due to accretion onto relativistic objects of any mass is found, although the current data do not exclude the presence of either a High Mass X-ray Binary or an Intermediate Mass Black Hole accreting at a low rate. Finally, we suggest the progenitor mass

  18. Mass transfer in binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Mccray, R.; Hatchett, S.

    1975-01-01

    The influence of X-ray heating on gas flows in binary X-ray systems is examined. A simple estimate is obtained for the evaporative wind flux from a stellar atmosphere due to X-ray heating which agrees with numerical calculations by Alme and Wilson (1974) but disagrees with calculations by Arons (1973) and by Basko and Sunyaev (1974) for the Her X-1/HZ Her system. The wind flux is sensitive to the soft X-ray spectrum. The self-excited wind mechanism does not work. Mass transfer in the Hercules system probably occurs by flow of the atmosphere of HZ Her through the gravitational saddle point of the system. The accretion gas stream is probably opaque with atomic density of not less than 10 to the 15th power per cu cm and is confined to a small fraction of 4(pi) steradians. Other binary X-ray systems are briefly discussed.

  19. X-rays From Centrifugal Magnetospheres in Massive Stars

    NASA Astrophysics Data System (ADS)

    Bard, Christopher; Townsend, Richard

    2015-01-01

    In the subset of massive OB stars with strong global magnetic fields, X-rays arise from magnetically confined wind shocks (Babel & Montmerle 1997). However, it is not yet clear what the effect of stellar rotation and mass-loss rate is on these wind shocks and resulting X-rays. Here, we present results from a grid of Arbitrary Rigid-Field Hydrodynamic simulations (ARFHD) of a B-star centrifugal magnetosphere with an eye towards quantifying the effect of stellar rotation and mass-loss rate on the level of X-ray emission. The results are also compared to a generalized XADM model for X-rays in dynamical magnetospheres (ud-Doula et al. 2014).

  20. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); DiStefano, Rosanne

    2003-01-01

    We have made remarkable progress in the study of luminous supersoft X-ray sources during the past year. We have begun to discover a population of ultraluminous SSSs (e.g., in NGC 300 [Kong & Di Stefano 20031 as well as in Ml0l [Di Stefano & Kong 2003]), which may be accreting intermediate-mass (50-100 solar mass) black holes. This work follows from an algorithm we have developed (Di Stefano & Kong 2003) to identify SSSs in external galaxies, selecting them from among each galaxy s total population of X-ray sources. We have applied the algorithm to approximately one dozen galaxies and will make it public after it has been published in its entirety. Through our own application of the algorithm, we have discovered SSSs in every galaxy, mapping their spatial distribution, to obtain important clues to their fundamental natures. We have discovered that there is a large population of X-ray sources which are slightly hotter (100-250 eV) than standard SSSs. Some of these may be accreting BHs with masses between roughly 50 anf 100 solar masses. To explore this possibility, we are working on theoretical models for the formation and evolution of such systems (Di Stefano 2003).

  1. X-RAY POLARIZATION FROM HIGH-MASS X-RAY BINARIES

    SciTech Connect

    Kallman, T.; Blondin, J.

    2015-12-10

    X-ray astronomy allows study of objects that may be associated with compact objects, i.e., neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically nonspherical, and likely noncircular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. Potential targets for future X-ray polarization observations are the high-mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early-type star. In this paper we show that X-ray polarization from HMXBs has a distinct signature that depends on the source inclination and orbital phase. The presence of the X-ray source displaced from the star creates linear polarization even if the primary wind is spherically symmetric whenever the system is viewed away from conjunction. Direct X-rays dilute this polarization whenever the X-ray source is not eclipsed; at mid-eclipse the net polarization is expected to be small or zero if the wind is circularly symmetric around the line of centers. Resonance line scattering increases the scattering fraction, often by large factors, over the energy band spanned by resonance lines. Real winds are not expected to be spherically symmetric, or circularly symmetric around the line of centers, owing to the combined effects of the compact object gravity and ionization on the wind hydrodynamics. A sample calculation shows that this creates polarization fractions ranging up to tens of percent at mid-eclipse.

  2. X-Ray Polarization from High Mass X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Dorodnitsyn, A.; Blondin, J.

    2015-01-01

    X-ray astronomy allows study of objects which may be associated with compact objects, i.e. neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically non-spherical, and likely non-circular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. A class of potential targets for future X-ray polarization observations is the high mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early type star. In this paper we show that X-ray polarization from HMXBs has a distinct signature which depends on the source inclination and orbital phase. The presence of the X-ray source displaced from the star creates linear polarization even if the primary wind is spherically symmetric whenever the system is viewed away from conjunction. Direct X-rays dilute this polarization whenever the X-ray source is not eclipsed; at mid-eclipse the net polarization is expected to be small or zero if the wind is circularly symmetric around the line of centers. Resonance line scattering increases the scattering fraction, often by large factors, over the energy band spanned by resonance lines. Real winds are not expected to be spherically symmetric, or circularly symmetric around the line of centers, owing to the combined effects of the compact object gravity and ionization on the wind hydrodynamics. A sample calculation shows that this creates polarization fractions ranging up to tens of percent at mid-eclipse.

  3. Applications of Indirect Imaging Techniques in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Harlaftis, E. T.

    A review is given on aspects of indirect imaging techniques in X-ray binaries which are used as diagnostics tools for probing the X-ray dominated accretion disc physics. These techniques utilize observed properties such as the emission line profile variability, the time delays between simultaneous optical/X-ray light curves, the light curves of eclipsing systems and the pulsed emission from the compact object in order to reconstruct the accretion disc's line emissivity (Doppler tomography), the irradiated disc and heated secondary (echo mapping), the outer disc structure (modified eclipse mapping) and the accreting regions onto the compact object, respectively.

  4. Recurrent X-ray Emission Variations of Eta Carinae and the Binary Hypothesis

    NASA Technical Reports Server (NTRS)

    Ishibashi, K.; Corcoran, M. F.; Davidson, K.; Swank, J. H.; Petre, R.; Drake, S. A.; Damineki, A.; White, S.

    1998-01-01

    Recent studies suggest that, the super-massive star eta Carinae may have a massive stellar companion (Damineli, Conti, and Lopes 1997), although the dense ejecta surrounding the star make this claim hard to test using conventional methods. Settling this question is critical for determining the current evolutionary state and future evolution of the star. We address this problem by an unconventional method: If eta Carinae is a binary, X-ray emission should be produced in shock waves generated by wind-wind collisions in the region between eta Carinae and its companion. Detailed X-ray monitoring of eta Carinae for more that) 2 years shows that the observed emission generally resembles colliding-wind X-ray emission, but with some significant discrepancies. Furthermore, periodic X-ray "flaring" may provide an additional clue to determine the presence of a companion star and for atmospheric pulsation in eta Carinae.

  5. Discovery of an X-Ray-emitting Contact Binary System 2MASS J11201034-2201340

    NASA Astrophysics Data System (ADS)

    Hu, Chin-Ping; Yang, Ting-Chang; Chou, Yi; Liu, L.; Qian, S.-B.; Hui, C. Y.; Kong, Albert K. H.; Lin, L. C. C.; Tam, P. H. T.; Li, K. L.; Ngeow, Chow-Choong; Chen, W. P.; Ip, Wing-Huen

    2016-06-01

    We report the detection of orbital modulation, a model solution, and the X-ray properties of a newly discovered contact binary, Two Micron All Sky Survey (2MASS) J11201034-2201340. We serendipitously found this X-ray point source outside the error ellipse when searching for possible X-ray counterparts of γ-ray millisecond pulsars among the unidentified objects detected by the Fermi Gamma-ray Space Telescope. The optical counterpart of the X-ray source (unrelated to the γ-ray source) was then identified using archival databases. The long-term Catalina Real-Time Transient Survey detected a precise signal with a period of P=0.28876208(56) days. A follow-up observation made by the Super Light Telescope of Lulin Observatory revealed the binary nature of the object. Utilizing archived photometric data of multi-band surveys, we construct the spectral energy distribution (SED), which is well fit by a K2V spectral template. The fitting result of the orbital profile using the Wilson-Devinney code suggests that 2MASS J11201034-2201340 is a short-period A-type contact binary and the more massive component has a cool spot. The X-ray emission was first noted in observations made by Swift, and then further confirmed and characterized by an XMM-Newton observation. The X-ray spectrum can be described by a power law or thermal Bremsstrahlung. Unfortunately, we could not observe significant X-ray orbital modulation. Finally, according to the SED, this system is estimated to be 690 pc from Earth with a calculated X-ray intensity of (0.7-1.5)× {10}30 erg s-1, which is in the expected range of an X-ray emitting contact binary.

  6. THE X-RAY SPECTRAL EVOLUTION OF GALACTIC BLACK HOLE X-RAY BINARIES TOWARD QUIESCENCE

    SciTech Connect

    Plotkin, Richard M.; Gallo, Elena; Jonker, Peter G.

    2013-08-10

    Most transient black hole X-ray binaries (BHXBs) spend the bulk of their time in a quiescent state, where they accrete matter from their companion star at highly sub-Eddington luminosities (we define quiescence here as a normalized Eddington ratio l{sub x} = L{sub 0.5-10{sub keV}}/L{sub Edd} < 10{sup -5}). Here, we present Chandra X-ray imaging spectroscopy for three BHXB systems (H 1743-322, MAXI J1659-152, and XTE J1752-223) as they fade into quiescence following an outburst. Multiple X-ray observations were taken within one month of each other, allowing us to track each individual system's X-ray spectral evolution during its decay. We compare these three systems to other BHXB systems. We confirm that quiescent BHXBs have softer X-ray spectra than low-hard-state BHXBs, and that quiescent BHXB spectral properties show no dependence on the binary system's orbital parameters. However, the observed anti-correlation between X-ray photon index ({Gamma}) and l{sub x} in the low-hard state does not continue once a BHXB enters quiescence. Instead, {Gamma} plateaus to an average ({Gamma}) = 2.08 {+-} 0.07 by the time l{sub x} reaches {approx}10{sup -5}. l{sub x} {approx} 10{sup -5} is thus an observationally motivated upper limit for the beginning of the quiescent spectral state. Our results are discussed in the context of different accretion flow models and across the black hole mass scale.

  7. THERMAL X-RAY EMISSION FROM THE SHOCKED STELLAR WIND OF PULSAR GAMMA-RAY BINARIES

    SciTech Connect

    Zabalza, V.; Paredes, J. M.; Bosch-Ramon, V.

    2011-12-10

    Gamma-ray-loud X-ray binaries are binary systems that show non-thermal broadband emission from radio to gamma rays. If the system comprises a massive star and a young non-accreting pulsar, their winds will collide producing broadband non-thermal emission, most likely originated in the shocked pulsar wind. Thermal X-ray emission is expected from the shocked stellar wind, but until now it has neither been detected nor studied in the context of gamma-ray binaries. We present a semi-analytic model of the thermal X-ray emission from the shocked stellar wind in pulsar gamma-ray binaries, and find that the thermal X-ray emission increases monotonically with the pulsar spin-down luminosity, reaching luminosities of the order of 10{sup 33} erg s{sup -1}. The lack of thermal features in the X-ray spectrum of gamma-ray binaries can then be used to constrain the properties of the pulsar and stellar winds. By fitting the observed X-ray spectra of gamma-ray binaries with a source model composed of an absorbed non-thermal power law and the computed thermal X-ray emission, we are able to derive upper limits on the spin-down luminosity of the putative pulsar. We applied this method to LS 5039, the only gamma-ray binary with a radial, powerful wind, and obtain an upper limit on the pulsar spin-down luminosity of {approx}6 Multiplication-Sign 10{sup 36} erg s{sup -1}. Given the energetic constraints from its high-energy gamma-ray emission, a non-thermal to spin-down luminosity ratio very close to unity may be required.

  8. Long-term optical variability of high-mass X-ray binaries. II. Spectroscopy

    NASA Astrophysics Data System (ADS)

    Reig, P.; Nersesian, A.; Zezas, A.; Gkouvelis, L.; Coe, M. J.

    2016-05-01

    Context. High-mass X-ray binaries are bright X-ray sources. The high-energy emission is caused by the accretion of matter from the massive companion onto a neutron star. The accreting material comes from either the strong stellar wind in binaries with supergiant companions or the cirscumstellar disk in Be/X-ray binaries. In either case, the Hα line stands out as the main source of information about the state of the accreting material. Aims: We present the results of our monitoring program to study the long-term variability of the Hα line in high-mass X-ray binaries. Our aim is to characterise the optical variability timescales and study the interaction between the neutron star and the accreting material. Methods: We fitted the Hα line with Gaussian profiles and obtained the line parameters and equivalent width. The peak separation in split profiles was used to determine the disk velocity law and estimate the disk radius. The relative intensity of the two peaks (V/R ratio) allowed us to investigate the distribution of gas particles in the disk. The equivalent width was used to characterise the degree of variability of the systems. We also studied the variability of the Hα line in correlation with the X-ray activity. Results: Our results can be summarised as follows: i) we find that Be/X-ray binaries with narrow orbits are more variable than systems with long orbital periods; ii) we show that a Keplerian distribution of gas particles provides a good description of the disks in Be/X-ray binaries, as it does in classical Be stars; iii) a decrease in the Hα equivalent width is generally observed after major X-ray outbursts; iv) we confirm that the Hα equivalent width correlates with disk radius; v) while systems with supergiant companions display multi-structured profiles, most of the Be/X-ray binaries show, at some epoch, double-peak asymmetric profiles, which indicates that density inhomogeneities is a common property in the disk of Be/X-ray binaries; vi) the

  9. High-mass X-ray binary populations. 1: Galactic modeling

    NASA Technical Reports Server (NTRS)

    Dalton, William W.; Sarazin, Craig L.

    1995-01-01

    Modern stellar evolutionary tracks are used to calculate the evolution of a very large number of massive binary star systems (M(sub tot) greater than or = 15 solar mass) which cover a wide range of total masses, mass ratios, and starting separations. Each binary is evolved accounting for mass and angular momentum loss through the supernova of the primary to the X-ray binary phase. Using the observed rate of star formation in our Galaxy and the properties of massive binaries, we calculate the expected high-mass X-ray binary (HMXRB) population in the Galaxy. We test various massive binary evolutionary scenarios by comparing the resulting HMXRB predictions with the X-ray observations. A major goal of this study is the determination of the fraction of matter lost from the system during the Roche lobe overflow phase. Curiously, we find that the total numbers of observable HMXRBs are nearly independent of this assumed mass-loss fraction, with any of the values tested here giving acceptable agreement between predicted and observed numbers. However, comparison of the period distribution of our HMXRB models with the observed period distribution does reveal a distinction among the various models. As a result of this comparison, we conclude that approximately 70% of the overflow matter is lost from a massive binary system during mass transfer in the Roche lobe overflow phase. We compare models constructed assuming that all X-ray emission is due to accretion onto the compact object from the donor star's wind with models that incorporate a simplified disk accretion scheme. By comparing the results of these models with observations, we conclude that the formation of disks in HMXRBs must be relatively common. We also calculate the rate of formation of double degenerate binaries, high velocity detached compact objects, and Thorne-Zytkow objects.

  10. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, Rosanne; Oliversen, Ronald J. (Technical Monitor)

    2004-01-01

    This has been a remarkably productive year. We have completed an algorithm to select SSSs in external galaxies which have been observed by Chandru or XMM-Newton. By applying this algorithm to new data, we have discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We have completed a study of SSSs in M31 and have also considered several other galaxies. From these studies, some population characteristics are beginning to emerge; these provide clues to the natures of the systems. We have considered ultraluminous SSSs in M1O1 and NGC 300. It is possible that these may correspond to accreting intermediate-mass black holes, rather than accreting white dwarfs. We have also studied individual systems, such as CAL 83, and have followed up on additional sources in fields we have studied, such as in the galaxy NGC 1313. NASA has released a press release on some of our work.

  11. IDENTIFICATION OF A POPULATION OF X-RAY-EMITTING MASSIVE STARS IN THE GALACTIC PLANE

    SciTech Connect

    Anderson, Gemma E.; Gaensler, B. M.; Kaplan, David L.; Posselt, Bettina; Slane, Patrick O.; Murray, Stephen S.; Drake, Jeremy J.; Grindlay, Jonathan E.; Hong, Jaesub; Lee, Julia C.; Mauerhan, Jon C.; Benjamin, Robert A.; Brogan, Crystal L.; Chakrabarty, Deepto; Drew, Janet E.; Lazio, T. Joseph W.; Steeghs, Danny T. H.; Van Kerkwijk, Marten H.

    2011-02-01

    We present X-ray, infrared, optical, and radio observations of four previously unidentified Galactic plane X-ray sources: AX J163252-4746, AX J184738-0156, AX J144701-5919, and AX J144547-5931. Detection of each source with the Chandra X-ray Observatory has provided sub-arcsecond localizations, which we use to identify bright infrared counterparts to all four objects. Infrared and optical spectroscopy of these counterparts demonstrate that all four X-ray sources are extremely massive stars, with spectral classifications: Ofpe/WN9 (AX J163252-4746), WN7 (AX J184738-0156 = WR121a), WN7-8h (AX J144701-5919), and OIf{sup +} (AX J144547-5931). AX J163252-4746 and AX J184738-0156 are both luminous, hard, X-ray emitters with strong Fe XXV emission lines in their X-ray spectra at {approx}6.7 keV. The multi-wavelength properties of AX J163252-4746 and AX J184738-0156 are not consistent with isolated massive stars or accretion onto a compact companion; we conclude that their X-ray emission is most likely generated in a colliding-wind binary (CWB) system. For both AX J144701-5919 and AX J144547-5931, the X-ray emission is an order of magnitude less luminous and with a softer spectrum. These properties are consistent with a CWB interpretation for these two sources also, but other mechanisms for the generation of X-rays cannot be excluded. There are many other as yet unidentified X-ray sources in the Galactic plane, with X-ray properties similar to those seen for AX J163252-4746, AX J184738-0156, AX J144701-5919, and AX J144547-5931. This may indicate a substantial population of X-ray-emitting massive stars and CWBs in the Milky Way.

  12. Luminous Binary Supersoft X-Ray Sources

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); DiStefano, Roseanne

    2005-01-01

    One of the key accomplishments of the two preceding years was our development of an algorithm to select SSSs in external galaxies which have been observed by Chandra or XMM-Newton. By applying this algorithm to data from a number of galaxies, we discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We call these new sources quasisoft sources (QSSs). During this past year, we have built on and extended this work. We have (1) continued to identify SSSs and QSSs in external galaxies, (2) worked on models for the sources and find that black hole models seem promising for a subset of them, and (3) have studied individual systems, especially M101-ULX1. This special system has been observed as an SSS in its high &ate, with a luminosity in excess of 10(exp 41) erg/s. It has also been observed as a QSS when it is less luminous, and as a hard source in its low state. It is one of the best candidates to be an accreting intermediate-mass black hole. We have several papers in preparation. Below we list papers which are complete, including only new work and papers whose status has changed (e.g., been accepted for publication) since our last report. In addition, our work on QSSs has received some publicity. It was the subject of a Chandra press release and was picked up by several media outlets.

  13. X-ray reverberation of the inner accretion disc in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Uttley, Phil; Cassatella, Pablo; Wilkinson, Tony; Wilms, Joern; Pottschmidt, Katja; Hanke, Manfred; Boeck, Moritz

    Rapid fluctuations in the Comptonised emission close to accreting compact objects should lead to reverberation of the accretion disc, both through X-ray heating of the disc (to produce a variable blackbody component) and also correlated changes in the disc reflection component, including the iron K line. If they can be detected, these reverberation signatures can provide powerful constraints on the geometry of the disc and Comptonising regions. The measure-ment of the reverberation delays will provide a natural 'yardstick' to measure the inner disc radius (in km, not R/M!) and so constrain the black hole spin or the neutron star equation of state. I will present new results from XMM-Newton and RXTE observations, which confirm the presence of X-ray reverberation in X-ray binary systems and allow the first measurement of reverberation delays. These results are a pathfinder which highlights the enormous po-tential of high-throughput spectral-timing with the proposed HTRS instrument on board the International X-ray Observatory.

  14. X-ray studies of three binary millisecond pulsars

    NASA Astrophysics Data System (ADS)

    Webb, N. A.; Olive, J.-F.; Barret, D.

    2005-10-01

    It is thought that millisecond pulsars with white dwarf companions are born from X-ray binaries. The majority of known systems have been studied uniquely in the radio domain, which limits our understanding of such systems. We present here the X-ray observations of the millisecond pulsar PSR J0218+4232 and the two faint millisecond pulsars PSR J0751+1807 and PSR J1012+5307, which we discuss in conjunction with radio observations. We confirm the previously detected X-ray pulsations of PSR J0218+4232 and we show that its folded lightcurve is strongly dependent on energy. We present evidence to suggest that the broad band X-ray spectrum for this pulsar may not be a simple power law, but that there is some evidence for an excess of soft thermal emission over the power law spectrum, in particular from the strongest pulse, in support of a heated polar cap model for this pulsar. We also present the X-ray spectra of the two faint millisecond pulsars as well as some evidence to suggest that both of these millisecond pulsars show pulsations in the X-ray band. We then discuss the implied nature of the magnetic field configuration as a means of discriminating between competing magnetic field evolution theories in millisecond pulsars.

  15. GIANT OUTBURSTS IN Be/X-RAY BINARIES

    SciTech Connect

    Martin, Rebecca G.; Nixon, Chris; Armitage, Philip J.; Lubow, Stephen H.; Price, Daniel J.

    2014-08-01

    Be/X-ray binary systems exhibit both periodic (Type I) X-ray outbursts and giant (Type II) outbursts, whose origins have remained elusive. We suggest that Type II X-ray outbursts occur when a highly misaligned decretion disk around the Be star becomes eccentric, allowing the compact object companion to capture a large amount of material at periastron. Using three-dimensional smoothed particle hydrodynamics simulations, we model the long-term evolution of a representative Be/X-ray binary system. We find that periodic (Type I) X-ray outbursts occur when the neutron star is close to periastron for all disk inclinations. Type II outbursts occur for large misalignment angles and are associated with eccentricity growth which occurs on a timescale of about 10 orbital periods. Mass capture from the eccentric decretion disk results in an accretion disk around the neutron star whose estimated viscous time is long enough to explain the extended duration of Type II outbursts. Previous studies suggested that the outbursts are caused by a warped disk but our results suggest that this is not sufficient; the disk must be both highly misaligned and eccentric to initiate a Type II accretion event.

  16. The nature of the X-ray pulsar in M 31: An intermediate-mass X-ray binary?

    NASA Astrophysics Data System (ADS)

    Karino, Shigeyuki

    2016-12-01

    The first finding of the spin period of an accreting neutron star in M 31 was recently reported. The observed spin period is 1.2 s, and it shows 1.27 d modulations due to orbital motion. From the orbital information, the mass donor could not be a giant massive star. On the other hand, its observed properties are very odd as those of typical low-mass X-ray binaries. In this study, we compare the observed binary parameters with theoretical models given by a stellar evolution track, and give a restriction on the possible mass range of the donor. According to the standard stellar evolution model, the donor star should be larger than 1.5 M⊙, which suggests that this system is a new member of a rare category, an intermediate-mass X-ray binary. The magnetic field strength of the neutron star suggested by the spin-up/down tendency in this system supports the possibility of an intermediate-mass donor.

  17. FORMATION OF MILLISECOND PULSARS FROM INTERMEDIATE- AND LOW-MASS X-RAY BINARIES

    SciTech Connect

    Shao Yong; Li Xiangdong

    2012-09-01

    We present a systematic study of the evolution of intermediate- and low-mass X-ray binaries consisting of an accreting neutron star of mass 1.0-1.8 M{sub Sun} and a donor star of mass 1.0-6.0 M{sub Sun }. In our calculations we take into account physical processes such as unstable disk accretion, radio ejection, bump-induced detachment, and outflow from the L{sub 2} point. Comparing the calculated results with the observations of binary radio pulsars, we report the following results. (1) The allowed parameter space for forming binary pulsars in the initial orbital period-donor mass plane increases with increasing neutron star mass. This may help explain why some millisecond pulsars with orbital periods longer than {approx}60 days seem to have less massive white dwarfs than expected. Alternatively, some of these wide binary pulsars may be formed through mass transfer driven by planet/brown-dwarf-involved common envelope evolution. (2) Some of the pulsars in compact binaries might have evolved from intermediate-mass X-ray binaries with anomalous magnetic braking. (3) The equilibrium spin periods of neutron stars in low-mass X-ray binaries are in general shorter than the observed spin periods of binary pulsars by more than one order of magnitude, suggesting that either the simple equilibrium spin model does not apply or there are other mechanisms/processes spinning down the neutron stars.

  18. Power colours: simple X-ray binary variability comparison

    NASA Astrophysics Data System (ADS)

    Heil, L. M.; Uttley, P.; Klein-Wolt, M.

    2015-04-01

    We demonstrate a new method of variability classification using observations of black hole X-ray binaries. Using `power colours' - ratios of integrated power in different Fourier frequency bands - we can clearly differentiate different canonical black hole states as the objects evolve during outburst. We analyse (˜2400) Rossi X-ray Timing Explorer observations of 12 transient low-mass black hole X-ray binaries and find that the path taken around the power colour-colour diagram as the sources evolve is highly consistent from object to object. We discuss how the consistency observed in the power colour-colour diagram between different objects allows for easy state classification based on only a few observations, and show how the power-spectral shapes can be simply classified using a single parameter, the power-spectral `hue'. To illustrate the benefits of our simple model-independent approach, we show that the persistent high-mass X-ray binary Cyg X-1 shows very similar power-spectral evolution to the transient black hole sources, with the main difference being caused by a combination of a lack of quasi-periodic oscillations and an excess of low-frequency power-law noise in the Cyg X-1 power spectra during the transitional state. We also compare the transient objects to the neutron star atoll source Aquila X-1, demonstrating that it traces a different path in the power colour-colour plot. Thus, power colours could be an effective method to classify newly discovered X-ray binaries.

  19. High ionisation absorption in low mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; De, K.; Fender, R.; Merloni, A.

    2016-05-01

    The advent of the new generation of X-ray telescopes yielded a significant step forward in our understanding of ionised absorption generated in the accretion discs of X-ray binaries. It has become evident that these relatively weak and narrow absorption features, sporadically present in the X-ray spectra of some systems, are actually the signature of equatorial outflows, which might carry away more matter than that being accreted. Therefore, they play a major role in the accretion phenomenon. These outflows (or ionised atmospheres) are ubiquitous during the softer states but absent during the power-law dominated, hard states, suggesting a strong link with the state of the inner accretion disc, presence of the radio-jet and the properties of the central source. Here, we discuss the current understanding of this field.

  20. Symbiotic X-ray binaries systems in the galaxy

    NASA Astrophysics Data System (ADS)

    Kuranov, A. G.; Postnov, K. A.

    2015-03-01

    The evolution of symbiotic X-ray binaries in the Galaxy is studied by the population synthesis method. We show that allowance for the nonstationarity of the regime of quasi-spherical subsonic accretion from the stellar wind of a giant onto slowly rotating neutron stars in these sources allows their observed positions on the neutron star spin period-X-ray luminosity diagramto be described in a wide range of stellar wind parameters. The derived distributions of sources in orbital periods, neutron star spin periods, and X-ray luminosities can be used to analyze the observations of Galactic sources in the range of luminosities ˜1032-1036 erg s-1 in the planned SRG/eROSITA all-sky survey.

  1. CLASSIFYING X-RAY BINARIES: A PROBABILISTIC APPROACH

    SciTech Connect

    Gopalan, Giri; Bornn, Luke; Vrtilek, Saeqa Dil

    2015-08-10

    In X-ray binary star systems consisting of a compact object that accretes material from an orbiting secondary star, there is no straightforward means to decide whether the compact object is a black hole or a neutron star. To assist in this process, we develop a Bayesian statistical model that makes use of the fact that X-ray binary systems appear to cluster based on their compact object type when viewed from a three-dimensional coordinate system derived from X-ray spectral data where the first coordinate is the ratio of counts in the mid- to low-energy band (color 1), the second coordinate is the ratio of counts in the high- to low-energy band (color 2), and the third coordinate is the sum of counts in all three bands. We use this model to estimate the probabilities of an X-ray binary system containing a black hole, non-pulsing neutron star, or pulsing neutron star. In particular, we utilize a latent variable model in which the latent variables follow a Gaussian process prior distribution, and hence we are able to induce the spatial correlation which we believe exists between systems of the same type. The utility of this approach is demonstrated by the accurate prediction of system types using Rossi X-ray Timing Explorer All Sky Monitor data, but it is not flawless. In particular, non-pulsing neutron systems containing “bursters” that are close to the boundary demarcating systems containing black holes tend to be classified as black hole systems. As a byproduct of our analyses, we provide the astronomer with the public R code which can be used to predict the compact object type of XRBs given training data.

  2. Classifying X-Ray Binaries: A Probabilistic Approach

    NASA Astrophysics Data System (ADS)

    Gopalan, Giri; Dil Vrtilek, Saeqa; Bornn, Luke

    2015-08-01

    In X-ray binary star systems consisting of a compact object that accretes material from an orbiting secondary star, there is no straightforward means to decide whether the compact object is a black hole or a neutron star. To assist in this process, we develop a Bayesian statistical model that makes use of the fact that X-ray binary systems appear to cluster based on their compact object type when viewed from a three-dimensional coordinate system derived from X-ray spectral data where the first coordinate is the ratio of counts in the mid- to low-energy band (color 1), the second coordinate is the ratio of counts in the high- to low-energy band (color 2), and the third coordinate is the sum of counts in all three bands. We use this model to estimate the probabilities of an X-ray binary system containing a black hole, non-pulsing neutron star, or pulsing neutron star. In particular, we utilize a latent variable model in which the latent variables follow a Gaussian process prior distribution, and hence we are able to induce the spatial correlation which we believe exists between systems of the same type. The utility of this approach is demonstrated by the accurate prediction of system types using Rossi X-ray Timing Explorer All Sky Monitor data, but it is not flawless. In particular, non-pulsing neutron systems containing “bursters” that are close to the boundary demarcating systems containing black holes tend to be classified as black hole systems. As a byproduct of our analyses, we provide the astronomer with the public R code which can be used to predict the compact object type of XRBs given training data.

  3. Blue Supergiant X-Ray Binaries in the Nearby Dwarf Galaxy IC 10

    NASA Astrophysics Data System (ADS)

    Laycock, Silas G. T.; Christodoulou, Dimitris M.; Williams, Benjamin F.; Binder, Breanna; Prestwich, Andrea

    2017-02-01

    In young starburst galaxies, the X-ray population is expected to be dominated by the relics of the most massive and short-lived stars, black hole and neutron-star high-mass X-ray binaries (XRBs). In the closest such galaxy, IC 10, we have made a multi-wavelength census of these objects. Employing a novel statistical correlation technique, we have matched our list of 110 X-ray point sources, derived from a decade of Chandra observations, against published photometric data. We report an 8σ correlation between the celestial coordinates of the two catalogs, with 42 X-ray sources having an optical counterpart. Applying an optical color–magnitude selection to isolate blue supergiant (SG) stars in IC 10, we find 16 matches. Both cases show a statistically significant overabundance versus the expectation value for chance alignments. The blue objects also exhibit systematically higher {f}x/{f}v ratios than other stars in the same magnitude range. Blue SG-XRBs include a major class of progenitors of double-degenerate binaries, hence their numbers are an important factor in modeling the rate of gravitational-wave sources. We suggest that the anomalous features of the IC 10 stellar population are explained if the age of the IC 10 starburst is close to the time of the peak of interaction for massive binaries.

  4. A radio pulsar/x-ray binary link.

    PubMed

    Archibald, Anne M; Stairs, Ingrid H; Ransom, Scott M; Kaspi, Victoria M; Kondratiev, Vladislav I; Lorimer, Duncan R; McLaughlin, Maura A; Boyles, Jason; Hessels, Jason W T; Lynch, Ryan; van Leeuwen, Joeri; Roberts, Mallory S E; Jenet, Frederick; Champion, David J; Rosen, Rachel; Barlow, Brad N; Dunlap, Bart H; Remillard, Ronald A

    2009-06-12

    Radio pulsars with millisecond spin periods are thought to have been spun up by the transfer of matter and angular momentum from a low-mass companion star during an x-ray-emitting phase. The spin periods of the neutron stars in several such low-mass x-ray binary (LMXB) systems have been shown to be in the millisecond regime, but no radio pulsations have been detected. Here we report on detection and follow-up observations of a nearby radio millisecond pulsar (MSP) in a circular binary orbit with an optically identified companion star. Optical observations indicate that an accretion disk was present in this system within the past decade. Our optical data show no evidence that one exists today, suggesting that the radio MSP has turned on after a recent LMXB phase.

  5. Modeling Broadband X-Ray Absorption of Massive Star Winds

    NASA Technical Reports Server (NTRS)

    Leutenegger, Maurice A.; Cohen,David H.; Zsargo, Janos; Martell, Erin M.; MacArthur, James P.; Owocki, Stanley P.; Gagne, Marc; Hillier, D. John

    2010-01-01

    We present a method for computing the net transition of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral ISM tabulation. Preliminary modeling of Chandra grating data indicates that the X-ray hardness trend of OB stars with spectral subtype cars largely be understood as a wind absorption effect.

  6. MODELING BROADBAND X-RAY ABSORPTION OF MASSIVE STAR WINDS

    SciTech Connect

    Leutenegger, Maurice A.; Zsargo, Janos; Martell, Erin M.; Owocki, Stanley P.; Gagne, Marc; Hillier, D. John

    2010-08-20

    We present a method for computing the net transmission of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming that the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes that all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength-dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral interstellar medium (ISM) tabulation. Preliminary modeling of Chandra grating data indicates that the X-ray hardness trend of OB stars with spectral subtype can largely be understood as a wind absorption effect.

  7. Formation and Destruction of Jets in X-ray Binaries

    NASA Technical Reports Server (NTRS)

    Kylafix, N. D.; Contopoulos, I.; Kazanas, D.; Christodoulou, D. M.

    2011-01-01

    Context. Neutron-star and black-hole X-ray binaries (XRBs) exhibit radio jets, whose properties depend on the X-ray spectral state e.nd history of the source. In particular, black-hole XRBs emit compact, 8teady radio jets when they are in the so-called hard state. These jets become eruptive as the sources move toward the soft state, disappear in the soft state, and then re-appear when the sources return to the hard state. The jets from neutron-star X-ray binaries are typically weaker radio emitters than the black-hole ones at the same X-ray luminosity and in some cases radio emission is detected in the soft state. Aims. Significant phenomenology has been developed to describe the spectral states of neutron-star and black-hole XRBs, and there is general agreement about the type of the accretion disk around the compact object in the various spectral states. We investigate whether the phenomenology describing the X-ray emission on one hand and the jet appearance and disappearance on the other can be put together in a consistent physical picture. Methods. We consider the so-called Poynting-Robertson cosmic battery (PRCB), which has been shown to explain in a natural way the formation of magnetic fields in the disks of AGNs and the ejection of jets. We investigate whether the PRCB can also explain the [ormation, destruction, and variability or jets in XRBs. Results. We find excellent agreement between the conditions under which the PRCB is efficient (i.e., the type of the accretion disk) and the emission or destruction of the r.adio jet. Conclusions. The disk-jet connection in XRBs can be explained in a natural way using the PRCB.

  8. Accretion and Outflows in X-ray Binaries: What's Really Going on During X-ray Quiescence

    NASA Astrophysics Data System (ADS)

    MacDonald, Rachel K. D.; Bailyn, Charles D.; Buxton, Michelle

    2015-01-01

    X-ray binaries, consisting of a star and a stellar-mass black hole, are wonderful laboratories for studying accretion and outflows. They evolve on timescales quite accessible to us, unlike their supermassive cousins, and allow the possibility of gaining a deeper understanding of these two common astrophysical processes. Different wavelength regimes reveal different aspects of the systems: radio emission is largely generated by outflows and jets, X-ray emission by inner accretion flows, and optical/infrared (OIR) emission by the outer disk and companion star. The search for relationships between these different wavelengths is thus an area of active research, aiming to reveal deeper connections between accretion and outflows.Initial evidence for a strong, tight correlation between radio and X-ray emission has weakened as further observations and newly-discovered sources have been obtained. This has led to discussions of multiple tracks or clusters, or the possibility that no overall relation exists for the currently-known population of X-ray binaries. Our ability to distinguish among these options is hampered by a relative lack of observations at lower luminosities, and especially of truly X-ray quiescent (non-outbursting) systems. Although X-ray binaries spend the bulk of their existence in quiescence, few quiescent sources have been observed and multiple observations of individual sources are largely nonexistent. Here we discuss new observations of the lowest-luminosity quiescent X-ray binary, A0620-00, and the place this object occupies in investigations of the radio/X-ray plane. For the first time, we also incorporate simultaneous OIR data with the radio and X-ray data.In December 2013 we took simultaneous observations of A0620-00 in the X-ray (Chandra), the radio (EVLA), and the OIR (SMARTS 1.3m). These X-ray and radio data allowed us to investigate similarities among quiescent X-ray binaries, and changes over time for this individual object, in the radio/X-ray

  9. X-Ray Properties of Black-Hole Binaries

    NASA Astrophysics Data System (ADS)

    Remillard, Ronald A.; McClintock, Jeffrey E.

    2006-09-01

    We review the properties and behavior of 20 X-ray binaries that contain a dynamically-confirmed black hole, 17 of which are transient systems. During the past decade, many of these transient sources were observed daily throughout the course of their typically year-long outburst cycles using the large-area timing detector aboard the Rossi X-Ray Timing Explorer. The evolution of these transient sources is complex. Nevertheless, there are behavior patterns common to all of them as we show in a comprehensive comparison of six selected systems. Central to this comparison are three X-ray states of accretion, which are reviewed and defined quantitatively. We discuss phenomena that arise in strong gravitational fields, including relativistically-broadened Fe lines, high-frequency quasi-periodic oscillations (100 450 Hz), and relativistic radio and X-ray jets. Such phenomena show us how a black hole interacts with its environment, thereby complementing the picture of black holes that gravitational wave detectors will provide. We sketch a scenario for the potential impact of timing/spectral studies of accreting black holes on physics and discuss a current frontier topic, namely, the measurement of black hole spin.

  10. X-ray Observations of Binary and Single Wolf-Rayet Stars with XMM-Newton and Chandra

    NASA Technical Reports Server (NTRS)

    Skinner, Stephen; Gudel, Manuel; Schmutz, Werner; Zhekov, Svetozar

    2006-01-01

    We present an overview of recent X-ray observations of Wolf-Rayet (WR) stars with XMM-Newton and Chandra. These observations are aimed at determining the differences in X-ray properties between massive WR + OB binary systems and putatively single WR stars. A new XMM spectrum of the nearby WN8 + OB binary WR 147 shows hard absorbed X-ray emission (including the Fe Ka line complex), characteristic of colliding wind shock sources. In contrast, sensitive observations of four of the closest known single WC (carbon-rich) WR stars have yielded only nondetections. These results tentatively suggest that single WC stars are X-ray quiet. The presence of a companion may thus be an essential factor in elevating the X-ray emission of WC + OB stars to detectable levels.

  11. The search for low-luminosity high-mass X-ray binaries and the study of X-ray populations in the Galactic disk

    NASA Astrophysics Data System (ADS)

    Fornasini, Francesca; Tomsick, John; Bodaghee, Arash; Rahoui, Farid; Krivonos, Roman; Corral-Santana, Jesus; An, Hongjun; Bauer, Franz E.; Gotthelf, Eric V.; Stern, Daniel; NuSTAR Galactic Plane Survey Team

    2016-01-01

    High-mass X-ray binaries (HMXBs), which consist of a neutron star (NS) or black hole (BH) accreting material from a massive stellar companion, provide valuable insights into the evolution of massive stars and the merger rates of NS/NS, NS/BH, and BH/BH binaries whose gravitational wave signatures will soon be detectable by facilities such as Advanced-LIGO. INTEGRAL discoveries of new classes of lower-luminosity HMXBs, some highly obscured and some showing extreme transient activity, as well as the recent discovery of the very quiescent and only known Be-BH binary, have considerably changed our understanding of clumping in massive stellar winds and the relative importance of different binary evolutionary channels. In order to better characterize the low-luminosity HMXB population, we have performed a survey of a square degree region in the direction of the Norma spiral arm with Chandra and NuSTAR. These surveys, combined with optical and infrared spectroscopic follow-up of the counterparts of hard X-ray sources, have yielded three HMXB candidates to date. Future radial-velocity follow-up of these candidates, as well as other Be HMXB candidates from the NuSTAR serendipitous survey, will help determine whether these sources truly are HMXBs and, if so, constrain the mass of the compact object in these systems. If confirmed, these HMXB candidates could extend our measurement of the HMXB luminosity function by about two orders of magnitude and provide important constraints on massive binary evolutionary models. In addition, the colliding wind binaries and pulsar wind nebulae discovered in the Norma X-ray survey will help shed light on other aspects of massive stellar evolution and massive stellar remnants. Finally, these surveys provide the opportunity to compare the hard X-ray populations in the Galactic disk and the Galactic Center. While the dominant hard X-ray populations in both of these Galactic regions appear to be cataclysmic variables (CVs), those in the Norma

  12. Different X-ray spectral evolution for black hole X-ray binaries in dual tracks of radio-X-ray correlation

    SciTech Connect

    Cao, Xiao-Feng; Wu, Qingwen; Dong, Ai-Jun

    2014-06-10

    Recently, an 'outlier' track of radio-X-ray correlation was found, which is much steeper than the former universal correlation, where dual tracks were speculated to be triggered by different accretion processes. In this work, we test this issue by exploring hard X-ray spectral evolution in four black-hole X-ray binaries with multiple, quasi-simultaneous radio and X-ray observations. First, we find that hard X-ray photon indices, Γ, are negatively and positively correlated with X-ray fluxes when the X-ray flux, F{sub 3-9} {sub keV}, is below and above a critical flux, F{sub X,} {sub crit}, which are consistent with predictions of the advection-dominated accretion flow and the disk-corona model, respectively. Second, and most importantly, we find that the radio-X-ray correlations are also clearly different when the X-ray fluxes are higher and lower than the critical flux as defined by X-ray spectral evolution. The data points with F{sub 3-9} {sub keV} ≳ F{sub X,} {sub crit} have a steeper radio-X-ray correlation (F{sub X}∝F{sub R}{sup b} and b ∼ 1.1-1.4), which roughly forms the ''outlier'' track. However, the data points with anti-correlation of Γ – F{sub 3-9} {sub keV} either stay in the universal track with b ∼ 0.61 or stay in the transition track (from the universal to 'outlier' tracks or vice versa). Therefore, our results support that the universal and ''outlier'' tracks of radio-X-ray correlations are regulated by radiatively inefficient and radiatively efficient accretion model, respectively.

  13. Discovery of a 3.6-hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Rappaport, Saul; Tennant, Allyn F.; Swartz, Douglas A.; Pooley, David; Madhusudhan, N.

    2006-01-01

    We report the discovery of an eclipsing X-ray binary with a 3.62-hr period within 24 arcsec of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the binary, and allows for a few very different interpretations. The most likely possibility is that the source lies within NGC 4214 and has an X-ray luminosity of up to 7e38. In this case the binary may well be comprised of a naked He-burning donor star with a neutron-star accretor, though a stellar-mass black-hole accretor cannot be completely excluded. There is no obvious evidence for a strong stellar wind in the X-ray orbital light curve that would be expected from a massive He star; thus, the mass of the He star should be <3-4 solar masses. If correct, this would represent a new class of very luminous X-ray binary----perhaps related to Cyg X-3. Other less likely possibilities include a conventional low-mass X-ray binary that somehow manages to produce such a high X-ray luminosity and is apparently persistent over an interval of years; or a foreground AM Her binary of much lower luminosity that fortuitously lies in the direction of NGC 4214. Any model for this system must accommodate the lack of an optical counterpart down to a limiting magnitude of 22.6 in the visible.

  14. The optical counterpart to the Be/X-ray binary SAX J2239.3+6116

    NASA Astrophysics Data System (ADS)

    Reig, P.; Blay, P.; Blinov, D.

    2017-01-01

    Context. Be/X-ray binaries represent the main group of high-mass X-ray binaries. The determination of the astrophysical parameters of the counterparts of these high-energy sources is important for the study of X-ray binary populations in our Galaxy. X-ray observations suggest that SAX J2239.3+6116 is a Be/X-ray binary. However, little is known about the astrophysical parameters of its massive companion. Aims: The main goal of this work is to perform a detailed study of the optical variability of the Be/X-ray binary SAX J2239.3+6116. Methods: We obtained multi-colour BVRI photometry and polarimetry and 4000-7000 Å spectroscopy. The 4000-5000 Å spectra allowed us to determine the spectral type and projected rotational velocity of the optical companion; the 6000-7000 Å spectra, together with the photometric magnitudes, were used to derive the colour excess E(B-V), estimate the distance, and to study the variability of the Hα line. Results: The optical counterpart to SAX J2239.3+6116 is a V = 14.8 B0Ve star located at a distance of 4.9 kpc. The interstellar reddening in the direction of the source is E(B-V) = 1.70 ± 0.03 mag. The monitoring of the Hα line reveals a slow long-term decline of its equivalent width since 2001. The line profile is characterized by a stable double-peak profile with no indication of large-scale distortions. We measured intrinsic optical polarization for the first time. Although somewhat higher than predicted by the models, the optical polarization is consistent with electron scattering in the circumstellar disk. Conclusions: We attribute the long-term decrease in the intensity of the Hα line to the dissipation of the circumstellar disk of the Be star. The longer variability timescales observed in SAX J2239.3+6116 compared to other Be/X-ray binaries may be explained by the wide orbit of the system.

  15. Relativistic model of neutron stars in X-ray binary

    NASA Astrophysics Data System (ADS)

    Kalam, Mehedi; Hossein, Sk Monowar; Islam, Rabiul; Molla, Sajahan

    2017-02-01

    In this paper, we study the inner structure of some neutron stars from theoretical as well as observational points of view. We calculate the probable radii, compactness (u) and surface redshift (Zs) of five neutron stars (X-ray binaries) namely 4U 1538-52, LMC X-4, 4U 1820-30, 4U 1608-52, EXO 1745-248. Here, we propose a stiff equation of state (EoS) of matter distribution which relates pressure with matter density. Finally, we check the stability of such kind of theoretical structure.

  16. AN X-RAY AND OPTICAL LIGHT CURVE MODEL OF THE ECLIPSING SYMBIOTIC BINARY SMC3

    SciTech Connect

    Kato, Mariko; Hachisu, Izumi; Mikolajewska, Joanna

    2013-01-20

    Some binary evolution scenarios for Type Ia supernovae (SNe Ia) include long-period binaries that evolve to symbiotic supersoft X-ray sources in their late stage of evolution. However, symbiotic stars with steady hydrogen burning on the white dwarf's (WD) surface are very rare, and the X-ray characteristics are not well known. SMC3 is one such rare example and a key object for understanding the evolution of symbiotic stars to SNe Ia. SMC3 is an eclipsing symbiotic binary, consisting of a massive WD and red giant (RG), with an orbital period of 4.5 years in the Small Magellanic Cloud. The long-term V light curve variations are reproduced as orbital variations in the irradiated RG, whose atmosphere fills its Roche lobe, thus supporting the idea that the RG supplies matter to the WD at rates high enough to maintain steady hydrogen burning on the WD. We also present an eclipse model in which an X-ray-emitting region around the WD is almost totally occulted by the RG swelling over the Roche lobe on the trailing side, although it is always partly obscured by a long spiral tail of neutral hydrogen surrounding the binary in the orbital plane.

  17. Connections between X-ray and optical variability in the low mass X-ray binary 1735-444

    NASA Technical Reports Server (NTRS)

    Corbet, R. H. D.; Smale, A. P.; Charles, P. A.; Lewin, W. H. G.; Menzies, J. W.

    1989-01-01

    The results of a long duration (4 day) simultaneous optical and X-ray observation of the low mass X-ray binary 1735-444 are presented. The observed X-ray and optical fluxes are correlated; the strength of this correlation is increased when allowance is made for the relatively large orbital modulation of the optical light. A simple interpretation of the optical radiation as reprocessed X-rays in a blackbody disk leads to an implausibly low disk temperature if the disk is assumed to have constant geometry. 1735-444 exhibits bimodal behavior having an X-ray spectral hardness ratio versus source intensity which is similar to that previously seen in sources such as Cyg X-2.

  18. Evidence for a massive stellar black hole in x ray Nova Muscae

    NASA Technical Reports Server (NTRS)

    Chen, Wan; Gehrels, Neil; Cheng, F. H.

    1992-01-01

    We present evidence that the X-ray Nova Muscae system contains a massive, greater than 10 M solarmass, black hole. A recently measured photometric binary mass function gives the black hole mass for this system as a function of orbital inclination angle. From the spectral redshift and width of the positron annihilation gamma-ray line observed by GRANAT/SIGMA, we find the accretion disk inclination angle to be 22 deg plus or minus 18 deg. Assuming the accretion disk lies in the orbital plane of the system, the black hole mass is found to have a lower limit of 14 M solar mass although statistics are poor. This is supported by spectral modeling of combined optical/UV/x-ray/gamma-ray data and by a new Nova Muscae distance limit we derive of greater than 3 kpc. The large mass for this black hole and the high binary mass ratio it implies (greater than 20) raise a serious challenge to theoretical models of the formation and evolution of massive binaries. The gamma-ray line technique introduced here can give tight constraints on orbital parameters when high-sensitivity line measurements are made by such missions as GRO.

  19. Magnetic Field in X-Ray Binary Cygnus X-1

    NASA Astrophysics Data System (ADS)

    Karitskaya, E. A.; Bochkarev, N. G.; Hubrig, S.; Gnedin, Yu. N.; Pogodin, M. A.; Yudin, R. V.; Agafonov, M. I.; Sharova, O. I.

    Our spectroscopic observations with FORS1 at 8.2-m VLT telescope (Paranal, Chile) lead to detection of magnetic field in the X-ray binary Cyg X-1. That is the first successful attempt of measuring magnetic field in a binary with a black hole. The value of the mean longitudinal magnetic field in optical component (O9.7 Iab supergiant) changes regularly with the orbital phase reaching its maximum of 130 G (σ≈20 G). The measurements based on Zeeman effect were carried through over all observed supergiant photosphere absorption spectral lines. Similar measurements over the emission line He II λ 4686 Å yielded a value of several hundreds Gauss of a smaller significance level. The system Doppler tomogram we build over the line profiles shows that He II λ 4686 Å originates in the outer regions of the accretion structure. The values measured correspond, in the frame of the disc accretion standard model, to a near-black-hole field of ˜ 10^8-10^9 G and may be responsible for the observed Cyg X-1 X-ray flickering. Also some consequences of such magnetic field existence in Cyg X-1 optical component photosphere were suggested.

  20. STATE TRANSITIONS IN LOW-MASS X-RAY BINARIES

    SciTech Connect

    Bradley, Charles K.; Frank, Juhan

    2009-10-10

    We investigate the model of disk/coronal accretion into a black hole. We show that the inner regions of an accretion disk in X-ray binaries can transform from a cool standard disk to an advection-dominated flow through the known properties of Coulomb interaction in a two-temperature plasma, viscous heating, radiative processes, and thermal conduction. A hot, diffuse corona covering the disk is powered by accretion, but it exchanges mass with the underlying cold disk. If the accretion rate in the system is low enough, we show that the corona evaporates the disk away, leaving an advective flow to continue toward the hole. In the soft/hard transition commonly seen in X-ray binaries, we show that this advective flow can recondense back onto the underlying disk if the change in the system's accretion rate is slow enough due to thermal conduction. Unabsorbed spectra are produced to test against observations as well as prediction of the location of truncation radii of the accretion disk.

  1. A New γ-Ray Loud, Eclipsing Low-mass X-Ray Binary

    NASA Astrophysics Data System (ADS)

    Strader, Jay; Li, Kwan-Lok; Chomiuk, Laura; Heinke, Craig O.; Udalski, Andrzej; Peacock, Mark; Shishkovsky, Laura; Tremou, Evangelia

    2016-11-01

    We report the discovery of an eclipsing low-mass X-ray binary at the center of the 3FGL error ellipse of the unassociated Fermi/Large Area Telescope γ-ray source 3FGL J0427.9-6704. Photometry from OGLE and the SMARTS 1.3 m telescope and spectroscopy from the SOAR telescope have allowed us to classify the system as an eclipsing low-mass X-ray binary (P = 8.8 hr) with a main-sequence donor and a neutron-star accretor. Broad double-peaked H and He emission lines suggest the ongoing presence of an accretion disk. Remarkably, the system shows separate sets of absorption lines associated with the accretion disk and the secondary, and we use their radial velocities to find evidence for a massive (˜1.8-1.9 M ⊙) neutron-star primary. In addition to a total X-ray eclipse with a duration of ˜2200 s observed with NuSTAR, the X-ray light curve also shows properties similar to those observed among known transitional millisecond pulsars: short-term variability, a hard power-law spectrum ({{Γ }}˜ 1.7), and a comparable 0.5-10 keV luminosity (˜ 2.4× {10}33 erg s-1). We find tentative evidence for a partial (˜ 60 % ) γ-ray eclipse at the same phase as the X-ray eclipse, suggesting the γ-ray emission may not be confined to the immediate region of the compact object. The favorable inclination of this binary is promising for future efforts to determine the origin of γ-rays among accreting neutron stars.

  2. Tugboat model for OB binaries, X-ray stars and pulsars.

    PubMed

    Helfand, D J; Tademaru, E

    1977-05-12

    An examination of the kinematical properties of binary OB stars, binary X-ray sources and pulsars suggests an evolutionary sequence linking an apparent low-velocity class of pulsars to the binary nature of their extreme Population I progenitors.

  3. A Unified Model of Low Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Balucinska-Church, M.; Church, M.

    2014-07-01

    We present a unified physical model of Low Mass X-ray Binaries explaining the basic Atoll and Z-track types of source. In all LMXB with luminosity above 1-2.10^{37} erg/s, we have a new fundamental result that the temperature of the Comptonizing ADC corona equals that of the neutron star, i.e. there is thermal equilibrium. This equilibrium explains the properties of the basic Banana State of Atoll sources. Below this luminosity, equilibrium breaks down, T_ADC rising towards 100 keV by an unknown heating mechanism, explaining the Island State. Above 5.10^{37} erg/s flaring begins in the GX-Atolls which we show is unstable nuclear burning. Above 1.10^{38} erg/s, LMXB are seen as Z-track sources. Flaring in these and the GX-Atolls occurs when the mass accretion rate to the neutron star falls to the critical value for unstable nuclear burning on the star. Below 2.10^{37} erg/s, a different unstable burning: X-ray bursting, takes over. We show that the Normal Branch of the Z-track consists simply of increasing mass accretion rate, as is the Banana State in Atolls. In the Horizontal Branch, a measured, strongly increasing radiation pressure of the neutron star disrupts the inner disk launching the relativistic jets seen on this branch.

  4. Evolution of Low-mass X-Ray Binaries: The Effect of Donor Evaporation

    NASA Astrophysics Data System (ADS)

    Jia, Kun; Li, Xiang-Dong

    2016-10-01

    Millisecond pulsars (MSPs) are thought to originate from low-mass X-ray binaries (LMXBs). The discovery of eclipsing radio MSPs, including redbacks and black widows, indicates that evaporation of the donor star by the MSP’s irradiation takes place during the LMXB evolution. In this work, we investigate the effect of donor evaporation on the secular evolution of LMXBs, considering different evaporation efficiencies and related angular momentum loss. We find that for widening LMXBs, the donor star leaves a less massive white dwarf than without evaporation; for contracting systems, evaporation can speed up the evolution, resulting in dynamically unstable mass transfer and possibly the formation of isolated MSPs.

  5. X-RAY OUTBURSTS OF LOW-MASS X-RAY BINARY TRANSIENTS OBSERVED IN THE RXTE ERA

    SciTech Connect

    Yan, Zhen; Yu, Wenfei E-mail: wenfei@shao.ac.cn

    2015-06-01

    We have performed a statistical study of the properties of 110 bright X-ray outbursts in 36 low-mass X-ray binary transients (LMXBTs) seen with the All-Sky Monitor (2–12 keV) on board the Rossi X-ray Timing Explorer (RXTE) in 1996–2011. We have measured a number of outburst properties, including peak X-ray luminosity, rate of change of luminosity on a daily timescale, e-folding rise and decay timescales, outburst duration, and total radiated energy. We found that the average properties, such as peak X-ray luminosity, rise and decay timescales, outburst duration, and total radiated energy of black hole LMXBTs, are at least two times larger than those of neutron star LMXBTs, implying that the measurements of these properties may provide preliminary clues to the nature of the compact object of a newly discovered LMXBT. We also found that the outburst peak X-ray luminosity is correlated with the rate of change of X-ray luminosity in both the rise and decay phases, which is consistent with our previous studies. Positive correlations between total radiated energy and peak X-ray luminosity, and between total radiated energy and the e-folding rise or decay timescale, are also found in the outbursts. These correlations suggest that the mass stored in the disk before an outburst is the primary initial condition that sets up the outburst properties seen later. We also found that the outbursts of two transient stellar-mass ultraluminous X-ray sources in M31 also roughly follow the correlations, which indicate that the same outburst mechanism works for the brighter outbursts of these two sources in M31 that reached the Eddington luminosity.

  6. Radiative efficiency of hot accretion flow and the radio/X-ray correlation in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Xie, Fu-Guo

    2016-02-01

    Significant progresses have been made since the discovery of hot accretion flow, a theory successfully applied to the low-luminosity active galactic nuclei (LLAGNs) and black hole (BH) X-ray binaries (BHBs) in their hard states. Motivated by these updates, we re-investigate the radiative efficiency of hot accretion flow. We find that, the brightest regime of hot accretion flow shows a distinctive property, i.e. it has a constant efficiency independent of accretion rates, similar to the standard thin disk. For less bright regime, the efficiency has a steep positive correlation with the accretion rate, while for faint regime typical of advection-dominated accretion flow, the correlation is shadower. This result can naturally explain the observed two distinctive correlations between radio and X-ray luminosities in black hole X-ray binaries. The key difference in systems with distinctive correlations could be the viscous parameter, which determines the critical luminosity of different accretion modes.

  7. Hot White Dwarf Donors in Ultracompact X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Bildsten, Lars

    2002-09-01

    The discovery of two accreting millisecond X-ray pulsars in binaries with ~43 minute orbital periods allows for a new probe of the donor's structure. For XTE J1751-305, only a hot white dwarf (WD) can fill the Roche lobe. A cold He WD is a possible solution for XTE J0929-314, although I will show that evolutionary arguments make a hot WD more likely. In addition to being larger than the T=0 models, these finite entropy, low-mass (Mc<0.03 Msolar) WDs have a minimum mass for a fixed core temperature. If they remain hot as they lose mass and expand, they can ``evaporate'' to leave an isolated millisecond radio pulsar. They also adiabatically expand upon mass loss at a rate faster than the growth of the Roche radius if the angular momentum deposited in the disk is not returned to the donor. If the timescale of the resulting runaway mass transfer is shorter than the viscous timescale in the outer disk, then the mass transfer instability of Ruderman & Shaham for He WDs would be realized. However, my estimates of these timescales still make the instability unlikely for adiabatic responses. I close by noting the possible impact of finite temperature WDs on our understanding of AM CVn binaries.

  8. Be/X-Ray Pulsar Binary Science with LOFT

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2011-01-01

    Accretion disks are ubiquitous in astronomical sources. Accretion powered pulsars are a good test bed for accretion disk physics, because unlike for other objects, the spin of the neutron star is directly observable allowing us to see the effects of angular momentum transfer onto the pulsar. The combination of a sensitive wide-field monitor and the large area detector on LOFT will enable new detailed studies of accretion powered pulsars which I will review. RXTE observations have shown an unusually high number of Be/X-ray pulsar binaries in the SMC. Unlike binaries in the Milky Way, these systems are all at the same distance, allowing detailed population studies using the sensitive LOFT WFM, potentially providing connections to star formation episodes. For Galactic accreting pulsar systems, LOFT will allow measurement of spectral variations within individual pulses, mapping the accretion column in detail for the first time. LOFT will also provide better constraints on magnetic fields in accreting pulsars, allowing measurements of cyclotron features, observations of transitions into the centrifugal inhibition regime, and monitoring of spin-up rate vs flux correlations. Coordinated multi-wavelength observations are crucial to extracting the best science from LOFT from these and numerous other objects.

  9. The donor star winds in High-Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Oskinova, Lida

    2014-10-01

    High-mass X-ray binaries (HMXBs) are essential astrophysical laboratories. These objects represent an advanced stage in the evolution of massive binary systems, after the initially more massive star has already collapsed in a supernova explosion, but its remnant, a neutron star or black hole, remains gravitationally bound. The stellar wind from the OB-type donor is partially accreted onto its compact companion powering its relatively high X-ray luminosity. Since HMXBs accrete from the stellar wind, parameters such as the donor's mass-loss rate, the velocity of the wind, and its clumpiness are of fundamental importance.This proposal takes advantage of the unique capabilities of HST/STIS for UV spectroscopy. We focus on the most populous in the Galaxy class of those HMXBs where the stellar wind of the OB donor is directly accreted onto a neutron star. Recently, a new sub-class of HMXBs - "supergiant fast X-ray transients" - was discovered. It has been proposed that these enigmatic objects can be explained by the specific properties of their donor-star winds. The only way to validate or disprove this hypothesis is by a studying the wind diagnostics lines in the UV spectra of donor stars. The observations proposed here will, for the first time, provide the UV spectra of this important new type of accreting binaries. Our state-of-the art non-LTE expanding stellar atmospheres and 3-D stellar wind simulations allow thorough exploitation of the STIS spectra. As a result we will obtain the wind parameters for a representative sample of six Galactic HMXBs, thus heightening our knowledge thereof considerably.

  10. Powerful jets from black hole X-ray binaries in low/hard X-ray states

    NASA Astrophysics Data System (ADS)

    Fender, R. P.

    2001-03-01

    Four persistent (Cygnus X-1, GX 339-4, GRS 1758-258 and 1E 1740.7-2942) and three transient (GS 2023+38, GRO J0422+32 and GS 1354-64) black hole X-ray binary systems have been extensively observed at radio wavelengths during extended periods in the low/hard X-ray state, which is characterized in X-rays by a hard power-law spectrum and strong variability. All seven systems show a persistent flat or inverted (in the sense that α>~0, where Sν~να) radio spectrum in this state, markedly different from the optically thin radio spectra exhibited by most X-ray transients within days of outburst. Furthermore, in none of the systems is a high-frequency cut-off to this spectral component detected, and there is evidence that it extends to near-infrared or optical regimes. Luminous persistent hard X-ray states in the black hole system GRS 1915+105 produce a comparable spectrum. This spectral component is considered to arise in synchrotron emission from a conical, partially self-absorbed jet, of the same genre as those originally considered for active galactic nuclei. Whatever the physical origin of the low/hard X-ray states, these self-similar outflows are an ever-present feature. The power in the jet component is likely to be a significant (>=5per cent) and approximately fixed fraction of the total accretion luminosity. The correlation between hard X-ray and synchrotron emission in all the sources implies that the jets are intimately related to the Comptonization process, and do not have very large bulk Lorentz factors, unless the hard X-ray emission is also beamed by the same factor.

  11. GALACTIC ULTRACOMPACT X-RAY BINARIES: DISK STABILITY AND EVOLUTION

    SciTech Connect

    Heinke, C. O.; Ivanova, N.; Engel, M. C.; Pavlovskii, K.; Sivakoff, G. R.; Gladstone, J. C.; Cartwright, T. F.

    2013-05-10

    We study the mass-transfer rates and disk stability conditions of ultracompact X-ray binaries (UCXBs) using empirical time-averaged X-ray luminosities from Paper I and compiled information from the literature. The majority of UCXBs are consistent with evolutionary tracks for white dwarf donors. Three UCXBs with orbital periods longer than 40 minutes have mass-transfer rates above 10{sup -10} M{sub Sun} yr{sup -1}, inconsistent with white dwarf donor tracks. We show that if helium star donors can retain their initial high entropy, they can explain the observed mass-transfer rates of these UCXBs. Several UCXBs show persistent luminosities apparently below the disk instability limit for irradiated He accretion disks. We point out that a predominantly C and/or O disk (as observed in the optical spectra of several) lowers the disk instability limit, explaining this disagreement. The orbital period and low time-averaged mass-transfer rate of 2S 0918-549 provide evidence that the donor star is a low-entropy C/O white dwarf, consistent with optical spectra. We combine existing information to constrain the masses of the donors in 4U 1916-053 (0.064 {+-} 0.010 M{sub Sun }) and 4U 1626-67 (<0.036 M{sub Sun} for a 1.4 M{sub Sun} neutron star). We show that 4U 1626-67 is indeed persistent, and not undergoing a transient outburst, leaving He star models as the best explanation for the donor.

  12. Catalogue of Be/X-ray binary systems in the Small Magellanic Cloud: X-ray, optical and IR properties

    NASA Astrophysics Data System (ADS)

    Coe, M. J.; Kirk, J.

    2015-09-01

    This is a catalogue of ˜70 X-ray emitting binary systems in the Small Magellanic Cloud (SMC) that contain a Be star as the mass donor in the system and a clear X-ray pulse signature from a neutron star. The systems are generally referred to as Be/X-ray binaries. It lists all their known binary characteristics (orbital period, eccentricity), the measured spin period of the compact object, plus the characteristics of the Be star (spectral type, size of the circumstellar disc, evidence for non-radial pulsations behaviour). For the first time data from the Spitzer Observatory are combined with ground-based data to provide a view of these systems out into the far-IR. Many of the observational parameters are presented as statistical distributions and compared to other similar populations (e.g. isolated Be & B stars) in the SMC, and to other Be/X-ray systems in the Milky Way. In addition, previous important results are re-investigated using this excellently homogenous sample. In particular, the evidence for a bimodality in the spin period distribution is shown to be even stronger than first proposed, and the correlation between orbital period and circumstellar disc size seen in galactic sources is shown to be clearly present in the SMC systems and quantized for the first time.

  13. The low-mass X-ray binary LMC X-2

    SciTech Connect

    Crampton, D.; Hutchings, J.B.; Cowley, A.P.; Schmidtke, P.C.; Thompson, I.B. Arizona State Univ., Tempe Mount Wilson and Las Campanas Observatories, Pasadena, CA )

    1990-06-01

    Spectroscopic and photometric observations of LMC X-2 reveal the source to be an X-ray binary with a relatively long orbital period, probably 12.5 days. It appears to be a partially eclipsing system. It is one of a small subclass of low-mass X-ray binaries with longer orbital periods and higher X-ray luminosity than average, which contain a compact object accreting material from an evolving giant companion. 26 refs.

  14. X-ray spectral diagnostics of activity in massive stars

    NASA Astrophysics Data System (ADS)

    Cohen, David H.; Wollman, Emma E.; Leutenegger, Maurice A.

    2011-07-01

    X-rays give direct evidence of instabilities, time-variable structure, and shock heating in the winds of O stars. The observed broad X-ray emission lines provide information about the kinematics of shock-heated wind plasma, enabling us to test wind-shock models. And their shapes provide information about wind absorption, and thus about the wind mass-loss rates. Mass-loss rates determined from X-ray line profiles are not sensitive to density-squared clumping effects, and indicate mass-loss rate reductions of factors of 3 to 6 over traditional diagnostics that suffer from density-squared effects. Broad-band X-ray spectral energy distributions also provide mass-loss rate information via soft X-ray absorption signatures. In some cases, the degree of wind absorption is so high, that the hardening of the X-ray SED can be quite significant. We discuss these results as applied to the early O stars ζ Pup (O4 If), 9 Sgr (O4 V((f))), and HD 93129A (O2 If*).

  15. The atmospheric structures of the companion stars of eclipsing binary x ray sources

    NASA Technical Reports Server (NTRS)

    Clark, George W.

    1992-01-01

    This investigation was aimed at determining structural features of the atmospheres of the massive early-type companion stars of eclipse x-ray pulsars by measurement of the attenuation of the x-ray spectrum during eclipse transitions and in deep eclipse. Several extended visits were made to ISAS in Japan by G. Clark and his graduate student, Jonathan Woo to coordinate the Ginga observations and preliminary data reduction, and to work with the Japanese host scientist, Fumiaki Nagase, in the interpretation of the data. At MIT extensive developments were made in software systems for data interpretation. In particular, a Monte Carlo code was developed for a 3-D simulation of the propagation of x-rays from the neutron star through the ionized atmosphere of the companion. With this code it was possible to determine the spectrum of Compton-scattered x-rays in deep eclipse and to subtract that component from the observed spectra, thereby isolating the software component that is attributable in large measure to x-rays that have been scattered by interstellar grains. This research has culminated in the submission of paper to the Astrophysical Journal on the determination of properties of the atmosphere of QV Nor, the BOI companion of 4U 1538-52, and the properties of interstellar dust grains along the line of sight from the source. The latter results were an unanticipated byproduct of the investigation. Data from Ginga observations of the Magellanic binaries SMC X-1 and LMC X-4 are currently under investigation as the PhD thesis project of Jonathan Woo who anticipated completion in the spring of 1993.

  16. The Mysterious sdO X-ray Binary BD+37°442

    NASA Astrophysics Data System (ADS)

    Heber, U.; Geier, S.; Irrgang, A.; Schneider, D.; Barbu-Barna, I.; Mereghetti, S.; La Palombara, N.

    2014-04-01

    Pulsed X-ray emission in the luminous, helium-rich sdO BD +37°442 has recently been discovered (La Palombara et al. 2012). It was suggested that the sdO star has a neutron star or white dwarf companion with a spin period of 19.2 s. After HD 49798, which has a massive white dwarf companion spinning at 13.2 s in an 1.55 day orbit, this is only the second O-type subdwarf from which X-ray emission has been detected. We report preliminary results of our ongoing campaign to obtain time-resolved high-resolution spectroscopy using the CAFE instrument at Calar Alto observatory and SARG at the Telescopio Nationale Galileo. Atmospheric parameters were derived via a quantitative NLTE spectral analysis. The line fits hint at an unusually large projected rotation velocity. Therefore it seemed likely that BD +37°442 is a binary similar to HD 49798 and that the orbital period is also similar. The level of X-ray emission from BD +37°442 could be explained by accretion from the sdO wind by a neutron star orbiting at a period of less than ten days. Hence, we embarked on radial velocity monitoring in order to derive the binary parameters of the BD+37°442 system and obtained 41 spectra spread out over several month in 2012. Unlike for HD 49798, no radial velocity variations were found and, hence, there is no dynamical evidence for the existence of a compact companion yet. The origin of the pulsed X-ray emission remains as a mystery.

  17. X-Ray Binary Populations in a Cosmological Context, Including NuSTAR Predictions

    NASA Technical Reports Server (NTRS)

    Cardiff, Ann Hornschemeier

    2011-01-01

    The new ultradeep 4 Ms Chandra Deep Field South has afforded the deepest view ever of X-ray binary populations. We report on the latest results on both LMXB and HMXB evolution out to redshifts of approximately four, including comparison with the latest theoretical models, using this deepest-ever view of the X-ray universe with Chandra. The upcoming NuSTAR mission will open up X-ray binary populations in the hard X-ray band, similar to the pioneering work of Fabbiano et al. in the Einstein era. We report on plans to study both Local Group and starburst galaxies as well as the implications those observations may have for X-ray binary populations in galaxies contributing to the Cosmic X-ray Background.

  18. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

    St.-Louis, Nicole; Moffat, Anthony F. J.

    Massive stars start their lives above a mass of ~8 time solar, finally exploding after a few million years as core-collapse or pair-production supernovae. Above ~15 solar masses, they also spend most of their lives driving especially strong, hot winds due to their extreme luminosities. All of these aspects dominate the ecology of the Universe, from element enrichment to stirring up and ionizing the interstellar medium. But when they occur in close pairs or groups separated by less than a parsec, the interaction of massive stars can lead to various exotic phenomena which would not be seen if there were no binaries. These depend on the actual separation, and going from wie to close including colliding winds (with non-thermal radio emission and Wolf-Rayet dust spirals), cluster dynamics, X-ray binaries, Roche-lobe overflow (with inverse mass-ratios and rapid spin up), collisions, merging, rejuventation and massive blue stragglers, black-hole formation, runaways and gamma-ray bursts. Also, one wonders whether the fact that a massive star is in a binary affects its parameters compared to its isolated equivalent. These proceedings deal with all of these phenomena, plus binary statistics and determination of general physical properties of massive stars, that would not be possible with their single cousins. The 77 articles published in these proceedings, all based on oral talks, vary from broad revies to the lates developments in the field. About a third of the time was spent in open discussion of all participants, both for ~5 minutes after each talk and 8 half-hour long general dialogues, all audio-recorded, transcribed and only moderately edited to yield a real flavour of the meeting. The candid information in these discussions is sometimes more revealing than the article(s) that preceded them and also provide entertaining reading. The book is suitable for researchers and graduate students interested in stellar astrophysics and in various physical processes involved when

  19. Compact Objects In Binary Systems: Formation and Evolution of X-ray Binaries and Tides in Double White Dwarfs

    NASA Astrophysics Data System (ADS)

    Valsecchi, Francesca

    Binary star systems hosting black holes, neutron stars, and white dwarfs are unique laboratories for investigating both extreme physical conditions, and stellar and binary evolution. Black holes and neutron stars are observed in X-ray binaries, where mass accretion from a stellar companion renders them X-ray bright. Although instruments like Chandra have revolutionized the field of X-ray binaries, our theoretical understanding of their origin and formation lags behind. Progress can be made by unravelling the evolutionary history of observed systems. As part of my thesis work, I have developed an analysis method that uses detailed stellar models and all the observational constraints of a system to reconstruct its evolutionary path. This analysis models the orbital evolution from compact-object formation to the present time, the binary orbital dynamics due to explosive mass loss and a possible kick at core collapse, and the evolution from the progenitor's Zero Age Main Sequence to compact-object formation. This method led to a theoretical model for M33 X-7, one of the most massive X-ray binaries known and originally marked as an evolutionary challenge. Compact objects are also expected gravitational wave (GW) sources. In particular, double white dwarfs are both guaranteed GW sources and observed electromagnetically. Although known systems show evidence of tidal deformation and a successful GW astronomy requires realistic models of the sources, detached double white dwarfs are generally approximated to point masses. For the first time, I used realistic models to study tidally-driven periastron precession in eccentric binaries. I demonstrated that its imprint on the GW signal yields constrains on the components' masses and that the source would be misclassified if tides are neglected. Beyond this adiabatic precession, tidal dissipation creates a sink of orbital angular momentum. Its efficiency is strongest when tides are dynamic and excite the components' free

  20. On the relationship between circumstellar disc size and X-ray outbursts in Be/X-ray binaries

    NASA Astrophysics Data System (ADS)

    Monageng, I. M.; McBride, V. A.; Coe, M. J.; Steele, I. A.; Reig, P.

    2017-01-01

    We present long-term Hα monitoring results of five Be/X-ray binaries to study the Be disc size variations and their influence on type II (giant) X-ray outbursts. The work is done in the context of the viscous decretion disc model which predicts that Be discs in binary systems are truncated by resonant torques induced by the neutron star in its orbit. Our observations show that type II outbursts are not correlated (nor anticorrelated) with the disc size, as they are seen to occur both at relatively small and large Be disc radii. We discuss these observations in context of alternate interpretation of Be disc behaviour, such as precession, elongation and density effects, and with cognisance of the limitations of our disc size estimates.

  1. New Results from Chandra on the X-ray Emission from the Massive Black Hole in the Compact Starburst Galaxy Henize 2-10

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Reynolds, Mark; Miller, Jon M.; Sivakoff, Gregory R.; Greene, Jenny E.; Hickox, Ryan C.; Johnson, Kelsey E.

    2017-01-01

    We present follow-up X-ray observations of the candidate massive black hole (BH) in the nucleus of the low-mass, compact starburst galaxy Henize 2-10. Using new high-resolution observations from the Chandra X-ray Observatory totaling 200 ks in duration, as well as archival Chandra observations from 2001, we demonstrate the presence of a previously unidentified X-ray point source that is spatially coincident with the known nuclear radio source in Henize 2-10 (i.e., the massive BH). We show that the hard X-ray emission previously identified in the 2001 observation is dominated by a source that is distinct from the nucleus, with the properties expected for a high-mass X-ray binary. The X-ray luminosity of the nuclear source suggests the massive BH is radiating significantly below its Eddington limit, and the soft spectrum resembles other weakly accreting massive BHs including Sagittarius A*. Analysis of the X-ray light curve of the nuclear source reveals the tentative detection of a ~9-hour periodicity, although additional observations are required to confirm this result. Our study highlights the need for sensitive high-resolution X-ray observations to probe low-level accretion, which is the dominant mode of BH activity throughout the Universe.

  2. Binary interaction dominates the evolution of massive stars.

    PubMed

    Sana, H; de Mink, S E; de Koter, A; Langer, N; Evans, C J; Gieles, M; Gosset, E; Izzard, R G; Le Bouquin, J-B; Schneider, F R N

    2012-07-27

    The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.

  3. X-ray emission from star-forming galaxies - I. High-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Mineo, S.; Gilfanov, M.; Sunyaev, R.

    2012-01-01

    Based on a homogeneous set of X-ray, infrared and ultraviolet observations from Chandra, Spitzer, GALEX and 2MASS archives, we study populations of high-mass X-ray binaries (HMXBs) in a sample of 29 nearby star-forming galaxies and their relation to the star-formation rate (SFR). In agreement with previous results, we find that HMXBs are a good tracer of the recent star-formation activity in the host galaxy and their collective luminosity and number scale with the SFR: in particular, ?. However, the scaling relations still bear a rather large dispersion of rms ˜ 0.4 dex, which we believe is of a physical origin. We present the catalogue of 1055 X-ray sources detected within the D25 ellipse for galaxies of our sample and construct the average X-ray luminosity function (XLF) of HMXBs with substantially improved statistical accuracy and better control of systematic effects than achieved in previous studies. The XLF follows a power law with a slope of 1.6 in the log (LX) ˜ 35-40 luminosity range with moderately significant evidence for a break or cut-off at LX˜ 1040 erg s-1. As before, we did not find any features at the Eddington limit for a neutron star or a stellar-mass black hole. We discuss the implications of our results for the theory of binary evolution. In particular we estimate the fraction of compact objects that once in their lifetime experienced an X-ray active phase powered by accretion from a high-mass companion and obtain a rather large number, fX˜ 0.2 × (0.1 Myr/τX), where τX is the lifetime of the X-ray active phase. This is ˜4 orders of magnitude more frequent than in low-mass X-ray binaries (LMXBs). We also derive constraints on the mass distribution of the secondary star in HMXBs.

  4. Optical/IR - X-ray variability in black hole and neutron star X-ray binaries

    NASA Astrophysics Data System (ADS)

    Gandhi, Poshak; Casella, Piergiorgio; Marsh, Tom; Malzac, Julien; Russell, David; Littlefair, Stuart; Dallilar, Yigit; Eikenberry, Steve; Dhillon, Vik; Hardy, Liam

    2016-07-01

    Following 50+ years of X-ray studies, we are at the threshold of a new era of fast multiwavelength timing studies of X-ray binaries. The optical and infrared regimes can directly measure the peak emission of the jet and hot flow in many accretion systems. When combined with simultaneous X-ray observations, they can be a powerful tool to probe the accretion/outflow connection in 'real-time' and to measure key physical parameters of the various binary components. This field has long been handicapped by the lack of suitable detectors and the difficulty of multiwavelength coordination of observations, but this is set to change with new dedicated observatories becoming operational almost continually over the next decade. I will review advances made in this field, concentrating on results from multiwavelength observations of black hole binaries in the hard state and contrasting them with (the few) studies of neutron stars. I will also discuss prospects from upcoming missions, and argue that a concerted effort by the community is needed to make the next leap forward.

  5. Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni during Quiescence

    NASA Astrophysics Data System (ADS)

    Rana, Vikram; Loh, Alan; Corbel, Stephane; Tomsick, John A.; Chakrabarty, Deepto; Walton, Dominic J.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William; Fuerst, Felix; Gandhi, Poshak; Grefenstette, Brian W.; Hailey, Charles; Harrison, Fiona A.; Madsen, Kristin K.; Rahoui, Farid; Stern, Daniel; Tendulkar, Shriharsh; Zhang, William W.

    2016-04-01

    We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg at energies above 10 keV. The unabsorbed broadband (0.3-30 keV) quiescent luminosity of the source is 8.9 × 1032 erg s-1 for a distance of 2.4 kpc. The source shows clear variability on short timescales (an hour to a couple of hours) in the radio, soft X-ray, and hard X-ray bands in the form of multiple flares. The broadband X-ray spectra obtained from XMM-Newton and NuSTAR can be characterized with a power-law model having a photon index of Γ = 2.12 ± 0.07 (90% confidence errors); however, residuals at high energies indicate spectral curvature significant at a 3σ confidence level with the e-folding energy of the cutoff as {20}-7+20 keV. Such curvature can be explained using synchrotron emission from the base of a jet outflow. Radio observations using the VLA reveal that the spectral index evolves on very fast timescales (as short as 10 minutes), switching between optically thick and thin synchrotron emission, possibly due to instabilities in the compact jet or stochastic instabilities in the accretion rate. We explore different scenarios to explain this very fast variability.

  6. High Mass X-ray Binaries and Star Clusters in Starburst Galaxies

    NASA Astrophysics Data System (ADS)

    Prestwich, Andrea H.; Chandar, R.; Rangelov, B.; Jackson, F.

    2011-09-01

    High Mass X-ray Binaries (HMXB) are formed in copious numbers in starburst galaxies. Is there any relationship between HMXBs and young star clusters? Do HMXBs form preferentially in star clusters? What can star clusters tell us about nearby HMXBs, even if they are not directly related? We have studied a variety of nearby starburst galaxies -- including the Antennae, NGC 4449 (a star-bursting dwarf) and NGC 922 (a collisional ring galaxy). In all these systems, we find evidence that a large fraction of (but not all) HMXBs are spatially coincident with (or very close to) a star cluster. Approximately 50 percent of the clusters hosting bright HMXBs are extremely young -- less than 6 Myr. Stellar evolutionary models predict that all stars with initial masses higher than ≈ 30 M⊙ will have completed their main-sequence lifetime after 6 Myr. While still somewhat uncertain, models predict that stars this massive will end their lives as black holes. We therefore conclude that HMXBs coincident with these very young clusters are most likely black hole binaries. We also find evidence for a population of young (30-50 Myr) and intermediate age X-ray sources (100-300 Myr) that are associated with older clusters. The implications of these results for models of HMXB formation and evolution will be briefly discussed.

  7. Chandra and XMM monitoring of the black hole X-ray binary IC 10 X-1

    NASA Astrophysics Data System (ADS)

    Laycock, Silas G. T.; Cappallo, Rigel C.; Moro, Matthew J.

    2015-01-01

    The massive black hole (BH)+Wolf-Rayet (WR) binary IC 10 X-1 was observed in a series of 10 Chandra and two XMM-Newton observations spanning 2003-2012, showing consistent variability around 7 × 1037 erg s-1, with a spectral hardening event in 2009. We phase connected the entire light curve by folding the photon arrival times on a series of trial periods spanning the known orbital period and its uncertainty, refining the X-ray period to P = 1.45175(1) d. The duration of minimum flux in the X-ray eclipse is ˜5 h which together with the optical radial velocity (RV) curve for the companion yields a radius for the eclipsing body of 8-10 R⊙ for the allowed range of masses. The orbital separation (a1 + a2) = 18.5-22 R⊙ then provides a limiting inclination i > 63° for total eclipses to occur. The eclipses are asymmetric (egress duration ˜0.9 h) and show energy dependence, suggestive of an accretion disc hotspot and corona. The eclipse is much (˜5×) wider than the 1.5-2 R⊙ WR star, pointing to absorption/scattering in the dense wind of the WR star. The same is true of the close analog NGC 300 X-1. RV measurements of the He II [λλ4686] line from the literature show a phase shift with respect to the X-ray ephemeris such that the velocity does not pass through zero at mid-eclipse. The X-ray eclipse leads inferior conjunction of the RV curve by ˜90°, so either the BH is being eclipsed by a trailing shock/plume, or the He II line does not directly trace the motion of the WR star and instead originates in a shadowed partially ionized region of the stellar wind.

  8. Stellar kinematics of X-ray bright massive elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Lyskova, N.; Churazov, E.; Moiseev, A.; Sil'chenko, O.; Zhuravleva, I.

    2014-07-01

    We discuss a simple and fast method for estimating masses of early-type galaxies from optical data and compare the results with X-ray derived masses. The optical method relies only on the most basic observables such as the surface brightness I(R) and the line-of-sight velocity dispersion σp(R) profiles and provides an anisotropy-independent estimate of the galaxy circular speed Vc. The mass-anisotropy degeneracy is effectively overcome by evaluating Vc at a characteristic radius Rsweet defined from local properties of observed profiles. The sweet radius Rsweet is expected to lie close to R2, where I(R) ∝ R-2, and not far from the effective radius Reff. We apply the method to a sample of five X-ray bright elliptical galaxies observed with the 6 m telescope BTA-6 in Russia. We then compare the optical Vc estimate with the X-ray derived value, and discuss possible constraints on the non-thermal pressure in the hot gas and configuration of stellar orbits. We find that the average ratio of the optical Vc estimate to the X-ray one is equal to ≈0.98 with 11 per cent scatter, i.e. there is no evidence for the large non-thermal pressure contribution in the gas at ˜Rsweet. From analysis of the Lick indices Hβ, Mgb, Fe5270 and Fe5335, we calculate the mass of the stellar component within the sweet radius. We conclude that a typical dark matter fraction inside Rsweet in the sample galaxies is ˜60 per cent for the Salpeter initial mass function (IMF) and ˜75 per cent for the Kroupa IMF.

  9. Recognition of binary x-ray systems utilizing the doppler effect

    NASA Technical Reports Server (NTRS)

    Novak, B. L.

    1980-01-01

    The possibility of recognizing the duality of a single class of X-ray systems utilizing the Doppler effect is studied. The procedure is based on the presence of a period which coincides with the orbital period at the intensity of the radiation in a fixed energy interval of the X-ray component of a binary system.

  10. A Chandra X-ray census of the interacting binaries in old open clusters - NGC 188

    NASA Astrophysics Data System (ADS)

    Vats, Smriti; Van Den Berg, Maureen

    2017-01-01

    We present a new X-ray study of NGC 188, one of the oldest open clusters known in the Milky Way (7 Gyr). Our X-ray observation using the Chandra X-ray Observatory is aimed at uncovering the population of close interacting binaries in the cluster. We detect 84 X-ray sources with a limiting X-ray luminosity, LX ~ 4×1029 erg s-1 (0.3-7 keV), of which 28 are within the half-mass radius. Of these, 13 are proper-motion or radial-velocity cluster members, wherein we identify a mix of active binaries (ABs) and blue straggler stars (BSSs). We also identify one tentative cataclysmic variable (CV) candidate which is a known short-period photometric variable, but whose membership to NGC 188 is unknown. We have compared the X-ray luminosity per unit of cluster mass (i.e. the X-ray emissivity) of NGC 188 with those of other old Galactic open clusters and dense globular clusters (47 Tuc, NGC 6397). Our findings confirm the earlier result that old open clusters have higher X-ray emissivities than the globular clusters (LX ≥1×1030 erg s-1). This may be explained by dynamical encounters in globulars, which could have a net effect of destroying binaries, or the typically higher metallicities of open clusters. We find one intriguing X-ray source in NGC 188 that is a BSS and cluster member, whose X-ray luminosity cannot be explained by its currently understood binary configuration. Its X-ray detection invokes the need for a third companion in the system.

  11. ON NEUTRAL ABSORPTION AND SPECTRAL EVOLUTION IN X-RAY BINARIES

    SciTech Connect

    Miller, J. M.; Cackett, E. M.; Reis, R. C.

    2009-12-10

    Current X-ray observatories make it possible to follow the evolution of transient and variable X-ray binaries across a broad range in luminosity and source behavior. In such studies, it can be unclear whether evolution in the low-energy portion of the spectrum should be attributed to evolution in the source, or instead to evolution in neutral photoelectric absorption. Dispersive spectrometers make it possible to address this problem. We have analyzed a small but diverse set of X-ray binaries observed with the Chandra High Energy Transmission Grating Spectrometer across a range in luminosity and different spectral states. The column density in individual photoelectric absorption edges remains constant with luminosity, both within and across source spectral states. This finding suggests that absorption in the interstellar medium strongly dominates the neutral column density observed in spectra of X-ray binaries. Consequently, evolution in the low-energy spectrum of X-ray binaries should properly be attributed to evolution in the source spectrum. We discuss our results in the context of X-ray binary spectroscopy with current and future X-ray missions.

  12. Centaurus X-3. [early x-ray binary star spectroscopy

    NASA Technical Reports Server (NTRS)

    Hutchings, J. B.; Cowley, A. P.; Crampton, D.; Van Paradus, J.; White, N. E.

    1979-01-01

    Spectroscopic observations of Krzeminski's star at dispersions 25-60 A/mm are described. The primary is an evolved star of type O6-O8(f) with peculiarities, some of which are attributable to X-ray heating. Broad emission lines at 4640A (N III), 4686 A(He II) and H-alpha show self-absorption and do not originate entirely from the region near the X-ray star. The primary is not highly luminous (bolometric magnitude about -9) and does not show signs of an abnormally strong stellar wind. The X-ray source was 'on' at the time of optical observations. Orbital parameters are presented for the primary, which yield masses of 17 + or - 2 and 1.0 + or - 3 solar masses for the stars. The optical star is undermassive for its luminosity, as are other OB-star X-ray primaries. The rotation is probably synchronized with the orbital motion. The distance to Cen X-3 is estimated to be 10 + or - 1 kpc. Basic data for 12 early-type X-ray primaries are discussed briefly

  13. An Infrared Search for Binary Companions to White Dwarfs with Hard X-Ray Emission

    NASA Astrophysics Data System (ADS)

    O'Dwyer, Ian J.; Gruendl, Robert; Chu, You-Hua; Guerrero, Martin A.

    2002-08-01

    A white dwarf (WD) can emit soft (≪ 0.4 keV) X-rays, if it is hot enough, i.e., T_eff > 30,000 K for a pure hydrogen atmosphere or T_eff > 100,000 K for a hydrogen and helium atmosphere. A WD can also emit harder (> 0.5 keV) X-rays, if it has a close binary companion and mass transfer takes place, e.g., dwarf novae, polars, and cataclysmic variables. We found a large number of hard X-ray emitting WDs by cross-correlating the McCook & Sion (1999) catalog of WDs with the ROSAT point source database. We have verified the position of the WD, analysed the ROSAT data and extracted X-ray spectra to confirm the hard X-ray component. Since the only current explanation for hard X-ray emission from a WD involves a stellar companion and only five of the ~40 WDs that exhibit hard X-ray emission are known binary systems, we wish to investigate whether hard X-ray emssion is a useful diagnostic for the presence of companions to WDs. We request KPNO 2.1m SQIID near infrared photometric observations of a sample of 34 WDs, 23 of which exhibit hard X-ray emission, to look for an infrared excess consistent with the presence of a stellar companion.

  14. The Peculiar Galactic Center Neutron Star X-Ray Binary XMM J174457-2850.3

    NASA Technical Reports Server (NTRS)

    Degenaar, N.; Wijnands, R.; Reynolds, M. T.; Miller, J. M.; Altamirano, D.; Kennea, J.; Gehrels, N.; Haggard, D.; Ponti, G.

    2014-01-01

    The recent discovery of a milli-second radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different neutron star manifestations. The remarkable X-ray variability and hard X-ray spectrum of this object can potentially serve as a template to search for other X-ray binary radio pulsar transitional objects. Here we demonstrate that the transient X-ray source XMM J174457-2850.3 near the Galactic center displays similar X-ray properties. We report on the detection of an energetic thermonuclear burst with an estimated duration of 2 hr and a radiated energy output of 5E40 erg, which unambiguously demonstrates that the source harbors an accreting neutron star. It has a quiescent X-ray luminosity of Lx5E32 ergs and exhibits occasional accretion outbursts during which it brightens to Lx1E35-1E36 ergs for a few weeks (2-10 keV). However, the source often lingers in between outburst and quiescence at Lx1E33-1E34 ergs. This unusual X-ray flux behavior and its relatively hard X-ray spectrum, a power law with an index of 1.4, could possibly be explained in terms of the interaction between the accretion flow and the magnetic field of the neutron star.

  15. Sigma observations of the low mass X-ray binaries of the galactic bulge

    NASA Technical Reports Server (NTRS)

    Goldwurm, A.; Denis, M.; Paul, J.; Faisse, S.; Roques, J. P.; Bouchet, L.; Vedrenne, G.; Mandrou, P.; Sunyaev, R.; Churazov, E.

    1995-01-01

    The soft gamma-ray telescope (35-1300 keV) SIGMA aboard the high energy GRANAT space observatory has been monitoring the Galactic Bulge region for more than 2000 h of effective time since March 1990. In the resulting average 35-75 keV image we detected ten sources at a level of greater than 5 standard deviations, 6 of which can be identified with low mass X-ray binaries (LMXB). Among them, one is the 1993 X-ray nova in Ophiuchus (GRS 1726-249), one is an X-ray pulsar (GX 1+4), two are associated with X-ray bursters (GX 354-0 and A 1742-294) and two with bursting X-ray binaries in the globular clusters Terzan 2 and Terzan 1. Their spectral and long term variability behavior as measured by SIGMMA are presented and discussed.

  16. The Fundamental Plane of Radio Loud Quasars and X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Zhang, H. J.; Zhang, X.

    2016-05-01

    Several X-ray binaries (X-ray binaries) in low/hard state that follow a track of radio-X-ray correlation have been found in recent years. Dong et al. also found this relation in RQQs (radio quiet quasars). Black hole accretion and jet formation are scale invariants which form the fundamental plane of black hole activity. It is a plane given in the space of the black hole mass and the radio/X-ray luminosities. In this paper, we compile a sample of radio loud active galactic nuclei and find that: (1) The hard X-ray photon indices and Eddington ratios of our sample are positively correlated, similar to XRBs. The Eddington-scaled radio-X-ray correlation of our sample also has that of outliers. A radiatively efficient accretion flow can regulate the positively correlated X-ray spectral evolution and the steep radio-X-ray correlation. (2) We can present a fundamental plane for XRBs. Several XRBs and radio-loud quasars (RLQs) have similarities in the relation formed by the black-hole mass, radio and X-ray luminosities. The fundamental plane is lg LR=0.998+0.045-0.045 lg LX+0.592+0.049-0.049 lg MBH -6.56+1.605-1.605, where LR is the radio luminosity, LX is the X-ray luminosity, and MBH is the black hole mass. (3) The plane can be suitable for the RLQ black hole sources. And the X-ray binaries also agree to the relation.

  17. Stellar feedback from high-mass X-ray binaries in cosmological hydrodynamical simulations

    NASA Astrophysics Data System (ADS)

    Artale, M. C.; Tissera, P. B.; Pellizza, L. J.

    2015-04-01

    We explored the role of X-ray binaries composed by a black hole and a massive stellar companion [black hole X-ray binaries (BHXs)] as sources of kinetic feedback by using hydrodynamical cosmological simulations. Following previous results, our BHX model selects metal-poor stars (Z = [0, 10-4]) as possible progenitors. The model that better reproduces observations assumes that an ˜20 per cent fraction of low-metallicity black holes are in binary systems which produces BHXs. These sources are estimated to deposit ˜1052 erg of kinetic energy per event. With these parameters and in the simulated volume, we find that the energy injected by BHXs represents ˜30 per cent of the total energy released by Type II supernova and BHX events at redshift z ˜ 7 and then decreases rapidly as baryons get chemically enriched. Haloes with virial masses smaller than ˜1010 M⊙ (or Tvir ≲ 105 K) are the most directly affected ones by BHX feedback. These haloes host galaxies with stellar masses in the range 107-108 M⊙. Our results show that BHX feedback is able to keep the interstellar medium warm, without removing a significant gas fraction, in agreement with previous analytical calculations. Consequently, the stellar-to-dark matter mass ratio is better reproduced at high redshift. Our model also predicts a stronger evolution of the number of galaxies as a function of the stellar mass with redshift when BHX feedback is considered. These findings support previous claims that the BHXs could be an effective source of feedback in early stages of galaxy evolution.

  18. An X-ray spectroscopic study of the SMC X-1/Sk 160 X-ray binary system

    NASA Astrophysics Data System (ADS)

    Wojdowski, Patrick Stephen

    1999-11-01

    In this thesis, the properties of the circumstellar environment of the high-mass X-ray binary system SMC X- 1/Sk 160 are explored using observational data from several satellite X-ray observatories. First, we have investigated the cause of the quasiperiodic ~60 day high-state low-state X-ray flux variation, previously suggested, and now clearly evident in extensive BATSE and RXTE monitoring data. Data from short-term pointed observations with the Ginga, ROSAT, ASCA, and RXTE observatories, show that while the uneclipsed flux varies by as much as a factor of 20 between high and low states, the eclipsed flux consists of approximately the same flux of reprocessed radiation in both states. From this we conclude that the high-low cycle is due to a quasi-periodic occultation of the source, most likely by a precessing tilted accretion disk around the neutron star. Next, we investigate the composition and distribution of the wind of Sk 160, the supergiant companion of the X-ray star SMC X-1, by comparing an X-ray spectrum of the source, obtained with the ASCA observatory during an eclipse with the computed spectra of reprocessed radiation from circumstellar matter with various density distributions. We show that the metal abundance in the wind of SMC X-1 is no greater than a few tenths of solar, as has been determined for other objects in the Magellanic Clouds. We also show that the observed spectrum is not consistent with the density distributions of circumstellar matter of the spherically symmetric form derived for line-driven winds, nor the density distribution from a hydrodynamic simulation of the X-ray perturbed and line-driven wind by Blondin & Woo (1995). Essential properties of a density distribution that would yield agreement with the observed spectrum are defined. Finally, we discuss prospects for future studies of this kind based on high-resolution spectroscopy data expected from the AXAF mission. (Copies available exclusively from MIT Libraries, Rm. 14

  19. CLUSTERING BETWEEN HIGH-MASS X-RAY BINARIES AND OB ASSOCIATIONS IN THE MILKY WAY

    SciTech Connect

    Bodaghee, A.; Tomsick, J. A.; Rodriguez, J.

    2012-01-10

    We present the first direct measurement of the spatial cross-correlation function of high-mass X-ray binaries (HMXBs) and active OB star-forming complexes in the Milky Way. This result relied on a sample containing 79 hard X-ray-selected HMXBs and 458 OB associations. Clustering between the two populations is detected with a significance above 7{sigma} for distances <1 kpc. Thus, HMXBs closely trace the underlying distribution of the massive star-forming regions that are expected to produce the progenitor stars of HMXBs. The average offset of 0.4 {+-} 0.2 kpc between HMXBs and OB associations is consistent with being due to natal kicks at velocities of the order of 100 {+-} 50 km s{sup -1}. The characteristic scale of the correlation function suggests an average kinematical age (since the supernova phase) of {approx}4 Myr for the HMXB population. Despite being derived from a global view of our Galaxy, these signatures of HMXB evolution are consistent with theoretical expectations as well as observations of individual objects.

  20. The Environment of X-Ray Binaries in the Dwarf Starburst Galaxy NGC 1569

    NASA Astrophysics Data System (ADS)

    Clark, David M.; Eikenberry, Stephen S.; Raines, Steven N.

    2008-05-01

    We use deep, J and Ks observations of NGC 1569 acquired with FLAMINGOS on the KPNO 4-m to search for star cluster counterparts to X-ray binaries identified in archived Chandra images of this dwarf starburst galaxy. Performing near-IR photometry on the star cluster counterparts, we determine their colors, luminosities and masses. Comparing these results to the properties for all clusters in this galaxy, we search for trends in clusters associated with X-ray sources. Combining this study with FISICA, near-IR spectral observations, we further characterize the surroundings to X-ray binaries in NGC 1569. Contrasting this work with findings from a similar study performed on the Antennae galaxies, a large, merging system, we investigate the differences in X-ray binary environments.

  1. The Black Hole X-ray Binary Population of M51 as seen by Chandra

    NASA Astrophysics Data System (ADS)

    Kilgard, Roy E.; Dorn-Wallenstein, Trevor; Kuntz, K. D.; Desjardins, Tyler D.

    2014-06-01

    We present an analysis of the black hole X-ray binary population of the interacting galaxy system M51 from new and archival observations by the Chandra X-ray Observatory with total exposure time of nearly 1 Ms. This dataset allows us to probe spectral and temporal variability of the X-ray source population on timescales ranging from tens of seconds to years. We examine both the ultraluminous X-ray source (ULX) population, which likely consists of black hole binaries based solely on luminosity, and the less luminous binaries that show evidence for harboring black holes. We further examine the environments of these sources within the host galaxy using new and archival Hubble Space Telescope observations to determine the probable mass donor stars in the system. We also present initial results from an effort to study the interaction of the luminous X-ray binaries with the interstellar medium of M51. This sample includes all of the historical ULXs as well as a new transient ULX which is a probable black hole low mass X-ray binary.

  2. Formation, disruption and energy output of Population III X-ray binaries

    NASA Astrophysics Data System (ADS)

    Ryu, Taeho; Tanaka, Takamitsu L.; Perna, Rosalba

    2016-02-01

    The first astrophysical objects shaped the cosmic environment by reionizing and heating the intergalactic medium (IGM). Particularly, X-rays are very efficient at heating the IGM before reionization is complete. High-mass X-ray binaries (HMXBs) in early stellar populations are prime candidates for driving the thermal evolution of the IGM at redshifts z ≳ 20; however, their formation efficiency is not well understood. Using N-body simulations, we estimate the HMXB formation rate via mutual gravitational interactions of nascent, small groups of the Population III stars. We run two sets of calculations: (i) stars formed in small groups of five in nearly Keplerian initial orbits and (ii) collision of two such groups (an expected outcome of mergers of host protogalaxies). We find that HMXBs form at a rate of one per ≳ 104 M⊙ in newly born stars, and that they emit with a power of ˜1041 erg s-1 in the 2-10 keV band per star formation rate. This value is a factor of ˜102 larger than what is observed in star-forming galaxies at lower redshifts; the X-ray production from early HMXBs would have been even more copious, if they also formed in situ or via migration in protostellar discs. Combining our results with earlier studies suggests that early HMXBs were highly effective at heating the IGM and leaving a strong 21-cm signature. We discuss broader implications of our results, such as the rate of long gamma-ray bursts from Population III stars and the direct collapse channel for massive black hole formation.

  3. Common envelope mechanisms: constraints from the X-ray luminosity function of high-mass X-ray binaries

    SciTech Connect

    Zuo, Zhao-Yu; Li, Xiang-Dong E-mail: lixd@nju.edu.cn

    2014-12-10

    We use the measured X-ray luminosity function (XLF) of high-mass X-ray binaries (HMXBs) in nearby star-forming galaxies to constrain the common envelope (CE) mechanisms, which play a key role in governing the binary evolution. We find that the XLF can be reproduced quite closely under both CE mechanisms usually adopted, i.e., the α{sub CE} formalism and the γ algorithm, with a reasonable range of parameters considered. Provided that the parameter combination is the same, the γ algorithm is likely to produce more HMXBs than the α{sub CE} formalism, by a factor of up to ∼10. In the framework of the α{sub CE} formalism, a high value of α{sub CE} is required to fit the observed XLF, though it does not significantly affect the global number of the HMXB populations. We present the detailed components of the HMXB populations under the γ algorithm and compare them with those in Zuo et al. and observations. We suggest the distinct observational properties, as well as period distributions of HMXBs, may provide further clues to discriminate between these two types of CE mechanisms.

  4. Studying X-Ray Binaries with High Energy Frequency Quasi-Periodic Oscillations

    NASA Technical Reports Server (NTRS)

    Kaaret, P.; West, Donald K. (Technical Monitor)

    2002-01-01

    The goal of this investigation is to further our understanding of the dynamics of secreting neutron stars and black holes in the hope of using these systems as probes of the physics of strong gravitational fetus. The main focus of this work has been a multi-year program of simultaneous millisecond X-ray timing and spectral observations carried out with the Rossi X-Ray Timing Explorer (RXTE) to perform the X-ray timing and one of the satellites Asca, BeppoSAX, or Chandra to perform X-ray spectral measurements. With the advent of Chandra, we have extended our work to incLude extragalactic X-ray binaries. We conducted a comprehensive study of the X-ray and radio behavior of the Black Hole Candidate (BHC) X-ray transient XTE J1550-564 using RXTE, Chandra, and the Australian Telescope Compact Array (ATCA). We showed that strong radio emission is associated with major X-ray outbursts involving an X-ray state transition, while a compact radio jet is seen in the low/hard X-ray state found in the outburst decay. Interesting, the total energy required to produce the compact jet may be a substantial fraction of the total accretion energy of the system in that state. We also performed a detailed study of the spectral and timing properties of the decay. In joint RXTE/BeppoSAX observations of the neutron-star X-ray binary Cyg X-2, we discovered a correlation between the timing properties (the frequency of the horizontal branch oscillations) and the properties of a soft, thermal component of the X-ray spectrum. d e showed that more detX- ray from accreting neutron stars. We have completed analysis of RXTE observations of the X-ray transient SAX J1750.8-2900 made after detection of X-ray bursts from the source with the BeppoSAX Wide-Field Camera. We discovered millisecond oscillations in both the persistent emission and in the X-ray bursts.

  5. A deep census of the X-ray binary populations in the SMC

    NASA Astrophysics Data System (ADS)

    Zezas, Andreas; Antoniou, Vallia; Hong, JaeSub; Wright, Nick; Drake, Jeremy J.; Haberl, Frank; SMC XVP Collaboration

    2016-04-01

    The analysis of the deep Chandra survey of the Small Magellanic Cloud (SMC) (a Chandra X-ray Visionary Program) yielded a wealth of discrete X-ray sources down to a limiting luminosity of a few times 1032 erg/s. The survey is designed to sample stellar populations of ages between ~10 up to ~100Myr, in order to study the evolution of the X-ray binary populations as a function of age. Based on the comparison of the detected X-ray sources with photometric catalogs of the SMC, we identify over 100 High Mass X-ray binaries (HMXBs) associated with the SMC, 21 of which exhibit pulsations. We measure the formation rate of HMXBs as a function of the age of their parent stellar populations, and we find that it shows a clear peak at ages of ~30-40Myr. In addition we measure the X-ray luminosity function of HMXBs which shows a clear break at a luminosity of ~5×1034 erg/s, indicative of the onset of the propeller effect. We discuss these results in the context of X-ray binary populations in environments of different ages and metallicities.

  6. X-Ray Emission from Massive Stars in Cyg OB2

    NASA Astrophysics Data System (ADS)

    Rauw, G.; Nazé, Y.; Wright, N. J.; Drake, J. J.; Guarcello, M. G.; Prinja, R. K.; Peck, L. W.; Albacete Colombo, J. F.; Herrero, A.; Kobulnicky, H. A.; Sciortino, S.; Vink, J. S.

    2015-11-01

    We report on the analysis of the Chandra-ACIS data of O, B, and WR stars in the young association Cyg OB2. X-ray spectra of 49 O-stars, 54 B-stars, and 3 WR-stars are analyzed and for the brighter sources, the epoch dependence of the X-ray fluxes is investigated. The O-stars in Cyg OB2 follow a well-defined scaling relation between their X-ray and bolometric luminosities: {log}\\\\frac{{L}{{X}}}{{L}{bol}}=-7.2+/- 0.2. This relation is in excellent agreement with the one previously derived for the Carina OB1 association. Except for the brightest O-star binaries, there is no general X-ray overluminosity due to colliding winds in O-star binaries. Roughly half of the known B-stars in the surveyed field are detected, but they fail to display a clear relationship between LX and Lbol. Out of the three WR stars in Cyg OB2, probably only WR 144 is itself responsible for the observed level of X-ray emission, at a very low {log}\\\\frac{{L}{{X}}}{{L}{bol}}=-8.8+/- 0.2. The X-ray emission of the other two WR-stars (WR 145 and 146) is most probably due to their O-type companion along with a moderate contribution from a wind-wind interaction zone.

  7. Evidence For Quasi-Periodic X-ray Dips From An Ultraluminous X-ray Source: Implications for the Binary Motion

    NASA Technical Reports Server (NTRS)

    Pasham, Dheeraj R.; Strohmayer, Tod E.

    2013-01-01

    We report results from long-term (approx.1240 days) X-ray (0.3-8.0 keV) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the Swift/X-Ray Telescope. Here we expand on earlier work by Strohmayer (2009) who used only a part of the present data set. Our primary results are: (1) the discovery of sharp, quasi-periodic, energy-independent dips in the X-ray intensity that recur on average every 243 days, (2) the detection of an energy dependent (variability amplitude decreases with increasing energy), quasi-sinusoidal X-ray modulation with a period of 112.6 +/- 4 days, the amplitude of which weakens during the second half of the light curve, and (3) spectral evidence for an increase in photoelectric absorption during the last continuous segment of the data. We interpret the X-ray modulations within the context of binary motion in analogy to that seen in high-inclination accreting X-ray binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an orbital period of 243 +/- 23 days, in contrast to the 115.5 day quasi-sinusoidal period previously reported by Strohmayer (2009). We discuss the overall X-ray modulation within the framework of accretion via Roche-lobe overflow of the donor star. In addition, if the X-ray modulation is caused by vertically structured obscuring material in the accretion disk, this would imply a high value for the inclination of the orbit. A comparison with estimates from accreting X-ray binaries suggests an inclination > or approx.70deg. We note that, in principle, a precessing accretion disk could also produce the observed X-ray modulations.

  8. Spectral and Timing Nature of the Symbiotic X-Ray Binary 4U 1954+319: The Slowest Rotating Neutron Star in AN X-Ray Binary System

    NASA Technical Reports Server (NTRS)

    Enoto, Teruaki; Sasano, Makoto; Yamada, Shin'Ya; Tamagawa, Toru; Makishima, Kazuo; Pottschmidt, Katja; Marcu, Diana; Corbet, Robin H. D.; Fuerst, Felix; Wilms, Jorn

    2014-01-01

    The symbiotic X-ray binary (SyXB) 4U 1954+319 is a rare system hosting a peculiar neutron star (NS) and an M-type optical companion. Its approx. 5.4 hr NS spin period is the longest among all known accretion-powered pulsars and exhibited large (is approx. 7%) fluctuations over 8 yr. A spin trend transition was detected with Swift/BAT around an X-ray brightening in 2012. The source was in quiescent and bright states before and after this outburst based on 60 ks Suzaku observations in 2011 and 2012. The observed continuum is well described by a Comptonized model with the addition of a narrow 6.4 keV Fe-K alpha line during the outburst. Spectral similarities to slowly rotating pulsars in high-mass X-ray binaries, its high pulsed fraction (approx. 60%-80%), and the location in the Corbet diagram favor high B-field (approx. greater than 10(exp12) G) over a weak field as in low-mass X-ray binaries. The observed low X-ray luminosity (10(exp33)-10(exp35) erg s(exp-1)), probable wide orbit, and a slow stellar wind of this SyXB make quasi-spherical accretion in the subsonic settling regime a plausible model. Assuming a approx. 10(exp13) G NS, this scheme can explain the approx. 5.4 hr equilibrium rotation without employing the magnetar-like field (approx. 10(exp16) G) required in the disk accretion case. The timescales of multiple irregular flares (approx. 50 s) can also be attributed to the free-fall time from the Alfv´en shell for a approx. 10(exp13) G field. A physical interpretation of SyXBs beyond the canonical binary classifications is discussed.

  9. Spectral and Timing Nature of the Symbiotic X-Ray Binary 4U 1954+319: The Slowest Rotating Neutron Star in an X-Ray Binary System

    NASA Astrophysics Data System (ADS)

    Enoto, Teruaki; Sasano, Makoto; Yamada, Shin'ya; Tamagawa, Toru; Makishima, Kazuo; Pottschmidt, Katja; Marcu, Diana; Corbet, Robin H. D.; Fuerst, Felix; Wilms, Jörn

    2014-05-01

    The symbiotic X-ray binary (SyXB) 4U 1954+319 is a rare system hosting a peculiar neutron star (NS) and an M-type optical companion. Its ~5.4 hr NS spin period is the longest among all known accretion-powered pulsars and exhibited large (~7%) fluctuations over 8 yr. A spin trend transition was detected with Swift/BAT around an X-ray brightening in 2012. The source was in quiescent and bright states before and after this outburst based on 60 ks Suzaku observations in 2011 and 2012. The observed continuum is well described by a Comptonized model with the addition of a narrow 6.4 keV Fe-Kα line during the outburst. Spectral similarities to slowly rotating pulsars in high-mass X-ray binaries, its high pulsed fraction (~60%-80%), and the location in the Corbet diagram favor high B-field (gsim 1012 G) over a weak field as in low-mass X-ray binaries. The observed low X-ray luminosity (1033-1035 erg s-1), probable wide orbit, and a slow stellar wind of this SyXB make quasi-spherical accretion in the subsonic settling regime a plausible model. Assuming a ~1013 G NS, this scheme can explain the ~5.4 hr equilibrium rotation without employing the magnetar-like field (~1016 G) required in the disk accretion case. The timescales of multiple irregular flares (~50 s) can also be attributed to the free-fall time from the Alfvén shell for a ~1013 G field. A physical interpretation of SyXBs beyond the canonical binary classifications is discussed.

  10. ON THE APPARENT LACK OF Be X-RAY BINARIES WITH BLACK HOLES

    SciTech Connect

    Belczynski, Krzysztof; Ziolkowski, Janusz E-mail: jz@camk.edu.p

    2009-12-20

    In our Galaxy there are 64 Be X-ray binaries known to date. Out of these, 42 host a neutron star (NS), and for the remainder the nature of the companion is unknown. None, so far, are known to host a black hole (BH). There seems to be no apparent mechanism that would prevent formation or detection of Be stars with BHs. This disparity is referred to as a missing Be-BH X-ray binary problem. We point out that current evolutionary scenarios that lead to the formation of Be X-ray binaries predict that the ratio of binaries with NSs to the ones with BHs is rather high, F{sub NStoBH} approx 10-50, with the more likely formation models providing the values at the high end. The ratio is a natural outcome of (1) the stellar initial mass function that produces more NSs than BHs and (2) common envelope evolution (i.e., a major mechanism involved in the formation of interacting binaries) that naturally selects progenitors of Be X-ray binaries with NSs (binaries with comparable mass components have more likely survival probabilities) over ones with BHs (which are much more likely to be common envelope mergers). A comparison of this ratio (i.e., F{sub NStoBH} approx 30) with the number of confirmed Be-NS X-ray binaries (42) indicates that the expected number of Be-BH X-ray binaries is of the order of only approx0-2. This is entirely consistent with the observed Galactic sample.

  11. FORMATION AND EVOLUTION OF GALACTIC INTERMEDIATE/LOW-MASS X-RAY BINARIES

    SciTech Connect

    Shao, Yong; Li, Xiang-Dong

    2015-08-10

    We investigate the formation and evolutionary sequences of Galactic intermediate- and low-mass X-ray binaries (I/LMXBs) by combining binary population synthesis (BPS) and detailed stellar evolutionary calculations. Using an updated BPS code we compute the evolution of massive binaries that leads to the formation of incipient I/LMXBs and present their distribution in the initial donor mass versus initial orbital period diagram. We then follow the evolution of the I/LMXBs until the formation of binary millisecond pulsars (BMSPs). We find that the birthrate of the I/LMXB population is in the range of 9 × 10{sup −6}–3.4 × 10{sup −5} yr{sup −1}, compatible with that of BMSPs that are thought to descend from I/LMXBs. We show that during the evolution of I/LMXBs they are likely to be observed as relatively compact binaries with orbital periods ≲1 day and donor masses ≲0.3M{sub ⊙}. The resultant BMSPs have orbital periods ranging from less than 1 day to a few hundred days. These features are consistent with observations of LMXBs and BMSPs. We also confirm the discrepancies between theoretical predictions and observations mentioned in the literature, that is, the theoretical average mass transfer rates (∼10{sup −10} M{sub ⊙} yr{sup −1}) of LMXBs are considerably lower than observed, and the number of BMSPs with orbital periods ∼0.1–10 days is severely underestimated. These discrepancies imply that something is missing in the modeling of LMXBs, which is likely to be related to the mechanisms of the orbital angular momentum loss.

  12. Gas flow and generation of x ray emission in WR+OB binaries

    NASA Technical Reports Server (NTRS)

    Usov, V. V.

    1991-01-01

    The supersonic flow of the ionized gas in WR+OB binaries and X-ray generation are considered. X-ray emission is caused by gas heating up to temperatures of 10(exp 7) to 10(exp 8) K behind the front of shock waves. These are found in the collision of gas flowing out from the WR star with either the OB star's surface or the gas of the OB star's wind. The distribution of temperature and concentration behind the shock front are obtained. Using these distributions, the spectral power of bremsstrahlung X-ray emission of hot gas is calculated. Possible reasons that lead to a considerable difference between the observed parameters of X-ray emission of the WR binary of V 444 Cygni and the theoretically expected are discussed.

  13. Low-mass X-ray Binaries with RXTE

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Below are the publications which directly and indirectly evolved from this very successful program: 1) 'Search for millisecond periodicities in type I X-ray bursts of the Rapid Burster'; 2) 'High-Frequency QPOs in the 2000 Outburst of the Galactic Microquasar XTE J1550-564'; 3) 'Chandra and RXTE Spectroscopy of Galactic Microquasar XTE 51550-564 in Outburst'; 4) 'GX 339-4: back to life'; 5) 'Evidence for black hole spin in GX 339-4: XMM-Newton EPIC-PN and RXTE spectroscopy of the very high state'.

  14. X-ray observations of the accreting Be/X-ray binary pulsar A 0535+26 in outburst

    NASA Astrophysics Data System (ADS)

    Caballero, I.

    2009-04-01

    Neutron stars are compact objects, characterized by R~10-14 km radius, M~1.4Msun and extremely high central densities ~10e15 g/cm^3. If they are part of a binary system, a flow of matter can take place from the companion star onto the neutron star. The accretion of matter onto neutron stars is one of the most powerful sources of energy in the universe. The accretion of matter takes place under extreme physical conditions, with magnetic fields in the range B~10^(8-15)G, which are impossible to reproduce on terrestrial laboratories. Therefore, accreting neutron stars are unique laboratories to study the matter under extreme conditions. In this thesis, X-ray observations of the accreting Be/X-ray binary A 0535+26 during a normal (type I) outburst are presented. In this system, the neutron star orbits around the optical companion HDE 245770 in an eccentric orbit, and sometimes presents X-ray outbursts (giant or normal) associated with the passage of the neutron star through the periastron. After more than eleven years of quiescence, A 0535+26 showed outbursting activity in 2005. The normal outburst analyzed in this work took place in August/September 2005, and reached a maximum X-ray flux of ~400 mCrab in the 5-100 kev range. The outburst, which lasted for ~30 days, was observed with the RXTE and INTEGRAL observatories. We have measured the spectrum of the source. In particular, two absorption-like features, interpreted as fundamental and first harmonic cyclotron resonant scattering features, have been detected at E~46 kev and E~102 kev with INTEGRAL and RXTE. Cyclotron lines are the only direct way to measure the magnetic field of a neutron star. Our observations have allowed to confirm the magnetic field of A 0535+26 at the site of the X-ray emission to be B~5x10^12 G. We studied the luminosity dependence of the cyclotron line in A 0535+26, and contrary to other sources, we found no significant variation of the cyclotron line energy with the luminosity. Changes of

  15. Monte Carlo Simulator to Study High Mass X-Ray Binary System

    SciTech Connect

    Watanabe, Shin; Nagase, Fumiaki; Takahashi, Tadayuki; Sako, Masao; Kahn, Steve M.; Ishida, Manabu; Ishisaki, Yoshitaka; Paerels, Frederik; /Columbia U.

    2005-07-08

    We have developed a Monte Carlo simulator for astrophysical objects, which incorporate the transportation of X-ray photons in photoionized plasma. We applied the code to X-ray spectra of high mass X-ray binaries, Vela X-1 and GX 301-2, obtained with Chandra HETGS. By utilizing the simulator, we have successfully reproduced many emission lines observed from Vela X-1. The ionization structure and the matter distribution in the Vela X-1 system are deduced. For GX 301-2, we have derived the physical parameters of material surrounding the neutron star from fully resolved shape of the Compton shoulder in the iron K{alpha} line.

  16. The noncompact binary X-ray source 4U 2129+47

    NASA Technical Reports Server (NTRS)

    Mcclintock, J. E.; London, R. A.; Bond, H. E.; Grauer, A. D.

    1982-01-01

    The 5.2 hr X-ray binary 4U 2129+47 was observed for a full orbital cycle using the imaging proportional counter detector and the monitor proportional counter detector aboard the Einstein Observatory, as well as a 0.9 m reflector for 5 hrs continuous optical photometry. The X-ray and optical light curves, the X-ray spectrum, and the times of optical and X-ray minimum were determined. The shape of the 5.2 hr X-ray light curve is independent of energy. A partial X-ray eclipse occurred which was centered on the time of optical minimum and which lasted 20 percent of the orbital period. During this interval the X-ray intensity varied smoothly by a factor of three, and the light curve was symmetric relative to the time of minimum. These findings argue that the X-ray emitting region is extended and highly ionized. A model is presented in which an accretion disk corona scatters radiation from a central accreting neutron star.

  17. Towards a Unified View of Inhomogeneous Stellar Winds in Isolated Supergiant Stars and Supergiant High Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Martínez-Núñez, Silvia; Kretschmar, Peter; Bozzo, Enrico; Oskinova, Lidia M.; Puls, Joachim; Sidoli, Lara; Sundqvist, Jon Olof; Blay, Pere; Falanga, Maurizio; Fürst, Felix; Gímenez-García, Angel; Kreykenbohm, Ingo; Kühnel, Matthias; Sander, Andreas; Torrejón, José Miguel; Wilms, Jörn

    2017-03-01

    Massive stars, at least ˜10 times more massive than the Sun, have two key properties that make them the main drivers of evolution of star clusters, galaxies, and the Universe as a whole. On the one hand, the outer layers of massive stars are so hot that they produce most of the ionizing ultraviolet radiation of galaxies; in fact, the first massive stars helped to re-ionize the Universe after its Dark Ages. Another important property of massive stars are the strong stellar winds and outflows they produce. This mass loss, and finally the explosion of a massive star as a supernova or a gamma-ray burst, provide a significant input of mechanical and radiative energy into the interstellar space. These two properties together make massive stars one of the most important cosmic engines: they trigger the star formation and enrich the interstellar medium with heavy elements, that ultimately leads to formation of Earth-like rocky planets and the development of complex life. The study of massive star winds is thus a truly multidisciplinary field and has a wide impact on different areas of astronomy. In recent years observational and theoretical evidences have been growing that these winds are not smooth and homogeneous as previously assumed, but rather populated by dense "clumps". The presence of these structures dramatically affects the mass loss rates derived from the study of stellar winds. Clump properties in isolated stars are nowadays inferred mostly through indirect methods (i.e., spectroscopic observations of line profiles in various wavelength regimes, and their analysis based on tailored, inhomogeneous wind models). The limited characterization of the clump physical properties (mass, size) obtained so far have led to large uncertainties in the mass loss rates from massive stars. Such uncertainties limit our understanding of the role of massive star winds in galactic and cosmic evolution. Supergiant high mass X-ray binaries (SgXBs) are among the brightest X-ray

  18. Spectroscopy of Low Mass X-Ray Binaries: New Insights into Accretion

    NASA Technical Reports Server (NTRS)

    DilVrtilek, Saeqa; Mushotsky, Richard (Technical Monitor)

    2004-01-01

    This project is to observe two low mass X-ray binaries, chosen for their X-ray brightness, low column density, and diversity of accretion behavior. The high spectral resolution of the RGS, the broad energy range and tremendous collecting power of EPIC, and simultaneous optical monitoring with the OM are particularly well-suited to these studies. The second of two objects was observed on September of 2002. Data analysis for both observation has been completed: an investigation of the physical conditions of the emitting gas using emission and recombination line diagnostics to determine temperatures, densities, elemental abundances, and ionization structure. A study of behavior of the emission features as a function of binary orbit shows modulated behavior in one of the systems. A paper on "High-resolution observations of low-mass X-ray binaries" is near completion. The paper includes observations with the Chandra HETG that are not yet completed.

  19. A study of low mass x-ray binaries

    NASA Technical Reports Server (NTRS)

    Catura, Richard C.

    1994-01-01

    The entire effort under this contract during the period through January 1992 was devoted to a study of the cost and schedule required to put an upgraded Aries payload on the ASTRO-SPAS carrier provided by the German space agency, DARA. The ASTRO-SPAS is flown on the Space Shuttle, deployed by the crew for 5 to 7 days of free-flying observations and then recovered and returned to Earth. The spectrograph was to be provided by a collaboration involving the Lockheed Palo Alto Research Laboratory (LPARL), the Center for Astrophysics and Space Astronomy (CASA) at the U. of Colorado and the Mullard Space Science Laboratory (MSSL) in England. The payload for the ASTRO-SPAS mission included our own spectrograph and an instrument provided by Dr. Joachim Trumper of the Max Planck Institute (MPI) in Garching, Germany. A meeting was held in late July, 1991 with German scientists, DARA representatives and MBB, the ASTRO-SPAS spacecraft contractor. Sufficient information was exchanged to allow us to complete the study and the name LEXSA (Low Energy X-ray Spectrograph on ASTRO-SPAS) was given to our instrument and HERTA (High Energy x-Ray Telescope on ASTR0-SPAS) to the German instrument. The combination was called SPECTRO-SPAS. On October 1, 1991 CASA and LPARL submitted a cost and brief technical proposal to NASA on results of the study. The total cost over 4 fiscal years was 6.16 M dollars including CASA costs. NASA Headquarters was briefed on 3 October on details of the proposal. They found our costs reasonable, but indicated that the NASA FY '92 budget is extremely tight, they could not readily identify where the -S2.3M for LEXSA could be found and it was not clear that FY '93 would improve.

  20. FORMATION OF BLACK HOLE X-RAY BINARIES IN GLOBULAR CLUSTERS

    SciTech Connect

    Ivanova, N.; Heinke, C. O.; Woods, T. E.; Chaichenets, S.; Fregeau, J.; Lombardi, J. C.

    2010-07-10

    Inspired by the recent identification in extragalactic globular clusters of the first candidate black hole-white dwarf (BH-WD) X-ray binaries, where the compact accretors may be stellar-mass black holes (BHs), we explore how such binaries could be formed in a dynamical environment. We provide analyses of the formation rates via well-known formation channels like binary exchange and physical collisions and propose that the only possibility of forming BH-WD binaries is via coupling these usual formation channels with subsequent hardening and/or triple formation. In particular, we find that the most important mechanism for the creation of a BH-WD X-ray binary from an initially dynamically formed BH-WD binary is mass transfer induced in a triple system via the Kozai mechanism. Furthermore, we find that BH-WD binaries that evolve into X-ray sources can be formed by exchanges of a BH into a WD-WD binary or possibly by collisions of a BH and a giant star. If BHs undergo significant evaporation from the cluster or form a completely detached subcluster of BHs, then we cannot match the observationally inferred production rates even using the most optimistic estimates of formation rates. To explain the observations with stellar-mass BH-WD binaries, at least 1% of all formed BHs, or presumably 10% of the BHs present in the core now, must be involved in interactions with the rest of the core stellar population.

  1. The Peculiar Galactic Center Neutron Star X-Ray Binary XMM J174457-2850.3

    NASA Astrophysics Data System (ADS)

    Degenaar, N.; Wijnands, R.; Reynolds, M. T.; Miller, J. M.; Altamirano, D.; Kennea, J.; Gehrels, N.; Haggard, D.; Ponti, G.

    2014-09-01

    The recent discovery of a millisecond radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different neutron star manifestations. The remarkable X-ray variability and hard X-ray spectrum of this object can potentially serve as a template to search for other X-ray binary/radio pulsar transitional objects. Here we demonstrate that the transient X-ray source XMM J174457-2850.3 near the Galactic center displays similar X-ray properties. We report on the detection of an energetic thermonuclear burst with an estimated duration of sime2 hr and a radiated energy output of ~= 5 × 1040 erg, which unambiguously demonstrates that the source harbors an accreting neutron star. It has a quiescent X-ray luminosity of L X ~= 5 × 1032(D/6.5 kpc)2 erg s-1 and exhibits occasional accretion outbursts during which it brightens to L X ~= 1035-1036(D/6.5 kpc)2 erg s-1 for a few weeks (2-10 keV). However, the source often lingers in between outburst and quiescence at L X ~= 1033-1034(D/6.5 kpc)2 erg s-1. This peculiar X-ray flux behavior and its relatively hard X-ray spectrum, a power law with an index of Γ ~= 1.4, could possibly be explained in terms of the interaction between the accretion flow and the magnetic field of the neutron star.

  2. A search for X-ray polarization in cosmic X-ray sources. [binary X-ray sources and supernovae remnants

    NASA Technical Reports Server (NTRS)

    Hughes, J. P.; Long, K. S.; Novick, R.

    1983-01-01

    Fifteen strong X-ray sources were observed by the X-ray polarimeters on board the OSO-8 satellite from 1975 to 1978. The final results of this search for X-ray polarization in cosmic sources are presented in the form of upper limits for the ten sources which are discussed elsewhere. These limits in all cases are consistent with a thermal origin for the X-ray emission.

  3. A SYNCHROTRON SELF-COMPTON-DISK REPROCESSING MODEL FOR OPTICAL/X-RAY CORRELATION IN BLACK HOLE X-RAY BINARIES

    SciTech Connect

    Veledina, Alexandra; Poutanen, Juri; Vurm, Indrek E-mail: juri.poutanen@oulu.fi

    2011-08-10

    The physical picture of the emission mechanisms operating in the X-ray binaries was put under question by the simultaneous optical/X-ray observations with high time resolution. The light curves of the two energy bands appeared to be connected and the cross-correlation functions observed in three black hole binaries exhibited a complicated shape. They show a dip of the optical emission a few seconds before the X-ray peak and the optical flare just after the X-ray peak. This behavior could not be explained in terms of standard optical emission candidates (e.g., emission from the cold accretion disk or a jet). We propose a novel model, which explains the broadband optical to the X-ray spectra and the variability properties. We suggest that the optical emission consists of two components: synchrotron radiation from the non-thermal electrons in the hot accretion flow and the emission produced by reprocessing of the X-rays in the outer part of the accretion disk. The first component is anti-correlated with the X-rays, while the second one is correlated, but delayed and smeared relative to the X-rays. The interplay of the components explains the complex shape of the cross-correlation function, the features in the optical power spectral density as well as the time lags.

  4. LFN, QPO and fractal dimension of X-ray light curves from black hole binaries

    NASA Astrophysics Data System (ADS)

    Prosvetov, Art; Grebenev, Sergey

    The origin of the low frequency noise (LFN) and quasi-periodic oscillations (QPO) observed in X-ray flux of Galactic black hole binaries is still not recognized in spite of multiple studies and attempts to model this phenomenon. There are known correlations between the QPO frequency, X-ray power density, X-ray flux and spectral state of the system, but there is no model that can do these dependences understandable. For the low frequency (~1 Hz) QPO we still have no even an idea capable to explain their production and don't know even what part of an accretion disc is responsible for them. Here we attempted to measure the fractal dimension of X-ray light curves of several black hole X-ray binaries and to study its correlation with the frequency of quasi periodic oscillations observed in their X-ray light-curves. The fractal dimension is a measure of the space-filling capacity of the light curves' profile. To measure the fractal dimension we used R/S method, which is fast enough and has good reputation in financial analytic and materials sciences. We found that if no QPO were observed in X-ray flux from the particular source, the fractal dimension is equal to the unique value which is independent on the source, its luminosity or its spectral state. On the other hand if QPO were detected in the flux, the fractal dimension deviated from its usual value. Also, we found a clear correlation between the QPO frequency and the fractal dimension of the emission. The relationship between these two parameters is solid but nonlinear. We believe that the analysis of X-ray light curves of black hole binaries using the fractal dimension has a good scientific potential and may provide an addition information on the geometry of accretion flow and fundamental physical parameters of the system.

  5. Hystereses in dwarf nova outbursts and low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Hameury, J.-M.; Lasota, J.-P.; Knigge, C.; Körding, E. G.

    2017-04-01

    Context. The disc instability model (DIM) successfully explains why many accreting compact binary systems exhibit outbursts during which their luminosity increases by orders of magnitude. The DIM correctly predicts which systems should be transient and works regardless of whether the accretor is a black hole, a neutron star, or a white dwarf. However, it has been known for some time that the outbursts of X-ray binaries, which contain neutron-star or black-hole accretors, exhibit hysteresis in the X-ray hardness-intensity diagram (HID). More recently, it has been shown that the outbursts of accreting white dwarfs also show hysteresis, but in a diagram combining optical, EUV, and X-ray fluxes. Aims: We examine the nature of the hysteresis observed in cataclysmic variables and low-mass X-ray binaries. Methods: We used our disc evolution code for modelling dwarf nova outbursts, and constructed the hardness intensity diagram as predicted by the disc instability model. Results: We show explicitly that the standard DIM, modified only to account for disc truncation, can explain the hysteresis observed in accreting white dwarfs, but cannot explain that observed in X-ray binaries. Conclusions: The spectral evidence for the existence of different accretion regimes or components (disc, corona, jets, etc.) should only be based on wavebands that are specific to the innermost parts of the discs, i.e. EUV and X-rays; this task is difficult because of interstellar absorption. The existing data, however, indicate that a hysteresis is in the EUV - X-ray domain is present in SS Cyg.

  6. Evolution of X-ray Binary Populations of Globular Clusters: A Boltzmann study

    NASA Astrophysics Data System (ADS)

    Ghosh, Pranab; Banerjee, S.

    2008-03-01

    We present a Boltzmann scheme for studying evolution of compact-binary populations of globular clusters, including dynamical formation and destruction processes, and binary hardening processes. For those processes which are stochastic (e.g., tidal formation, collisional destruction, and collisional hardening), we study the continuous limit first. We then introduce our stochastic model, showing that the continuous limit is an excellent representation of the average of many "realizations" of stochastic processes. We explore the scaling of the number of X-ray binaries in a globular cluster with two essential cluster parameters measuring star-star and star-binary encounter rates, which we call Verbunt parameters. We show that our computed scalings are in good agreement with CHANDRA data on Galactic globular cluster X-ray binaries. We discuss ways of extending our scheme, and of handling evolution of the cluster background.

  7. Detection of an X-ray flare in the RS CVn binary Sigma Coronae Borealis

    NASA Technical Reports Server (NTRS)

    Agrawal, P. C.; Rao, A. R.; Riegler, G. R.

    1986-01-01

    The detection of an X-ray flare in the RS CVn binary Sigma Coronae Borealis with the Monitor Proportional Counter on the Einstein Observatory is described. During the 513 min of observation, an X-ray flare of 208 min duration was detected at a significance level of 26 sigma in the 1.19-10.16 keV band. The rise time of the flare is between 25 and 70 min and the decay time is greater than or equal to 34 min. The X-ray luminosity at the flare maximum is found to be 6 x 10 to the 30th erg/s and the total energy radiated in X-rays during the flare is 2 x 10 to the 34th erg. The energy spectrum in the flaring state is found to be harder (temperature T about 2.5 x 10 to the 7th K) compared to the one observed in the quiescent state (T about 6 x 10 to the 6th K). Applying the coronal loop model, the loop parameters are calculated and compared for the X-ray flares observed in the various RS CVn binaries and the sun. The significance of the differences in the observed and derived parameters of the X-ray flares is briefly discussed.

  8. Spectral variability in early-type binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Kallman, T. R.; Castor, J. I.; Olson, G. L.; Mccray, R.

    1984-01-01

    Theoretical models for the ionization of trace elements in a strong stellar wind by a compact binary X-ray source and for the resulting orbital phase dependence of the emergent soft X-ray spectra and the profiles of ultraviolet resonance lines are presented. Model results agree qualitatively with the X-ray and ultraviolet spectra of the system 4U 0900-40/HD 77581 and explain the suppression of the absorption profiles of the Si IV upsilon 1394 and C IV upsilon 1548 lines when the X-ray sources are in front of the star. The model predicts that the absorption profiles of the N V upsilon 1239 and O VI upsilon 1032 lines will be enhanced rather than suppresed during this orbital phase.Phase-dependent linear polarization in the resonance lines profiles is predicted. Future observations of these phase dependent effects in early-type binary X-ray systems may be used to investigate the dynamics of stellar winds and their interactions with the X-ray source.

  9. Spectral variability in early-type binary X-ray systems

    NASA Technical Reports Server (NTRS)

    Mccray, R.; Kallman, T. R.; Castor, J. I.; Olson, G. L.

    1984-01-01

    Theoretical models for the ionization of trace elements in a strong stellar wind by a compact binary X-ray source and for the resulting orbital phase dependence of the emergent soft X-ray spectra and the profiles of ultraviolet resonance lines are presented. Model results agree qualitatively with the X-ray and ultraviolet spectra of the system 4U 0900-40/HD 77581 and explain the suppression of the absorption profiles of the Si IV upsilon 1394 and C IV upsilon 1548 lines when the X-ray sources is in front of the star. The model predicts that the absorption profiles of the N V upsilon 1239 and O VI upsilon 1032 lines will be enhanced rather than suppressed during this orbital phase. We predict phase-dependent linear polarization in the resonance lines profiles. Future observations of these phase dependent effects in early-type binary X-ray systems may be used to investigate the dynamics of stellar winds and their interactions with the X-ray source.

  10. X-Ray Binary Phenomenology and Their Accretion Disk Structure

    NASA Astrophysics Data System (ADS)

    Kazanas, Demosthenes

    We propose a scheme that accounts for the broader spectral and temporal properties of galactic black hole X-ray transients. The fundamental notion behind this proposal is that the mass accretion rate, dot{M}, of the disks of these systems depends on the radius, as it has been proposed for ADIOS. We propose that, because of this dependence of dot{M} on radius, an accretion disk which is geometrically thin and cool at large radii converts into a geometrically thick, advection dominated, hot disk interior to a transition radius at which the local accretion rate drops below the square of the viscosity parameter, a condition for the existence of advection dominated flows. We argue also that such a transition requires in addition that the vertical disk support be provided by magnetic fields. As discussed in other chapters of this book, the origin of these fields is local to the disk by the Poynting Robertson battery, thereby providing a complete self-contained picture for the spectra and evolution of these systems.

  11. ROSAT observations of the x ray binary HD 154791

    NASA Technical Reports Server (NTRS)

    Kenyon, Scott J.

    1994-01-01

    We have been surveying the Taurus dark cloud for young stars using a variety of techniques. Two optical proper motion surveys identified 8 new pre-main sequence stars; an IRAS-based program discovered 6 new embedded sources and 4-6 new T Tauri stars. Finally, an optical objective prism survey found 12 new T Tauri stars. Our goal in this project is to examine and compare star formation in the dark clouds: Heiles cloud 2 (HCL2), L1537, L1538, and L1544. HCL2 is a very dense region actively forming young stars and contains 5-6 very young, deeply embedded sources; L1537 and L1538 have no known pre-main sequence stars; L1544 contains 7 optically visible T Tauri stars. These clouds appear roughly similar on optical sky survey plates. We would like to know why some of the clouds are active and why some are not. The first goal of the project is to survey the regions using IR photometry to identify very red pre-main sequence stars and X-ray imaging to identify solar-type young stars missed in the near-IR survey. We will follow up these observations with molecular line surveys to compare the conditions in various clouds with their star formation efficiencies.

  12. Recent Results of VLBA Imaging of X-Ray Binaries: the Newest and Oldest Microquasars

    NASA Astrophysics Data System (ADS)

    Mioduszewski, A. J.; Dhawan, V.; Rupen, M. P.

    2005-12-01

    X-ray binaries are stellar systems in which X-ray emission results from accretion from a normal star onto a compact object, i.e., a neutron star or black hole. Radio emission is associated both with X-ray outbursts, and with more stable conditions when the X-rays are dominated by a persistent hard power-law component. The VLBA has played a crucial role in studying these systems, by allowing detailed AU-scale imaging. This has allowed direct measurements of morphologies, orientations, expansion speeds, and scattering sizes, as well as detailed astrometric and proper motion studies. We review results from our group in this area, namely observations of H1743-322 and SS433.

  13. Theoretical spectra of nonmagnetized low-mass X-ray binaries

    NASA Technical Reports Server (NTRS)

    Czerny, Bozena; Czerny, Michal; Grindlay, Jonathan E.

    1986-01-01

    Theoretical X-ray spectra of low-mass X-ray binaries with negligible magnetic fields are presented. The geometry of the X-ray emitting region, the energetic efficiency of the accretion in the disk and in the boundary layer which leads to a relation between the disk and the boundary layer luminosities, and the irradiation of the disk by the boundary layer are studied. The model of the radiation spectrum emerging from the neutron star and the innermost part of the disk is presented. The relativistic and Doppler effects and their influence on the spectrum as a function of inclination angle are discussed. A simple method for comparing the spectrum model with observations by studying the hardness ratio is given, and the results for three X-ray sources in globular clusters observed by the Einstein satellite are presented. The range of applicability of the spectrum models is also discussed.

  14. Thermal X-ray emission from massive, fast rotating, highly magnetized white dwarfs

    NASA Astrophysics Data System (ADS)

    Cáceres, D. L.; de Carvalho, S. M.; Coelho, J. G.; de Lima, R. C. R.; Rueda, Jorge A.

    2017-03-01

    There is solid observational evidence on the existence of massive, M ∼ 1 M⊙, highly magnetized white dwarfs (WDs) with surface magnetic fields up to B ∼ 109 G. We show that, if in addition to these features, the star is fast rotating, it can become a rotation-powered pulsar-like WD and emit detectable high-energy radiation. We infer the values of the structure parameters (mass, radius, moment of inertia), magnetic field, rotation period and spin-down rates of a WD pulsar death-line. We show that WDs above the death-line emit blackbody radiation in the soft X-ray band via the magnetic polar cap heating by back flowing pair-created particle bombardment and discuss as an example the X-ray emission of soft gamma-repeaters and anomalous X-ray pulsars within the WD model.

  15. Herschel OBSERVATIONS OF DUST AROUND THE HIGH-MASS X-RAY BINARY GX 301-2

    SciTech Connect

    Servillat, M.; Coleiro, A.; Chaty, S.; Rahoui, F.; Zurita Heras, J. A.

    2014-12-20

    We aim at characterizing the structure of the gas and dust around the high-mass X-ray binary GX 301-2, a highly obscured X-ray binary hosting a hypergiant (HG) star and a neutron star, in order to better constrain its evolution. We used Herschel PACS to observe GX 301-2 in the far infrared and completed the spectral energy distribution of the source using published data or catalogs from the optical to the radio range (0.4 to 4 × 10{sup 4} μm). GX 301-2 is detected for the first time at 70 and 100 μm. We fitted different models of circumstellar (CS) environments to the data. All tested models are statistically acceptable, and consistent with an HG star at ∼3 kpc. We found that the addition of a free-free emission component from the strong stellar wind is required and could dominate the far-infrared flux. Through comparisons with similar systems and discussion on the estimated model parameters, we favor a disk-like CS environment of ∼8 AU that would enshroud the binary system. The temperature goes down to ∼200 K at the edge of the disk, allowing for dust formation. This disk is probably a rimmed viscous disk with an inner rim at the temperature of the dust sublimation temperature (∼1500 K). The similarities between the HG GX 301-2, B[e] supergiants, and the highly obscured X-ray binaries (particularly IGR J16318-4848) are strengthened. GX 301-2 might represent a transition stage in the evolution of massive stars in binary systems, connecting supergiant B[e] systems to luminous blue variables.

  16. X-ray spectroscopic and timing studies of galactic black hole binaries

    NASA Astrophysics Data System (ADS)

    Miller, Jon Matthew

    In rare cases, optical observations of Galactic binary star systems which are bright in the X-ray portion of the electromagnetic spectrum dynamically constrain the mass of one component to be well above theoretical limits for a neutron star. These systems—and systems with similar X-ray properties—are classified as black hole binaries. In this thesis, I report on observations of black hole binaries made with satellite observatories in the X-ray band. The region closest to the black hole is revealed in X-rays due to the viscous heating of matter that is accreted from the companion star. X-ray observations of these systems may therefore reveal General Relativistic effects. A fundamental and testable prediction of General Relativity is that matter may orbit more closely around black holes with significant angular momentum. I have investigated the possibility of black hole “spin” and the geometry of accretion flows in these systems using X-ray continuum spectroscopy, fast variability studies, and the shape of iron fluorescent emission lines in this band. I present evidence for black hole spin in XTE J1550-564, XTE J1650- 500, and XTE J1748-248. Spin is not required by high- resolution spectral analysis of the archetypical Galactic black hole—Cygnus X-1—but a thermal accretion disk plus hot corona geometry is confirmed. Studies of XTE J1118+480 and GRS 1758-258 at low X-ray luminosity reveal that models for radiatively-inefficient accretion do not satisfactorily describe the geometry in these systems. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)/

  17. Spectroscopy of Low Mass X-Ray Binaries: New Insights into Accretion. Revised

    NASA Technical Reports Server (NTRS)

    DilVrtilek, Saeqa; Mushotzky, Richard (Technical Monitor)

    2001-01-01

    This project is to observe two low mass X-ray binaries, chosen for their X-ray brightness, low column density, and diversity of accretion behavior. The high spectral resolution of the RGS, the broad energy range and tremendous collecting power of EPIC, and simultaneous optical monitoring with the OM are particularly well-suited to these studies. observation of one of the two objects has taken place and the data were received in late November. The second object is yet to be observed. Over the next year we will: investigate the physical conditions of the emitting gas using emission and recombination line diagnostics to determine temperatures, densities, elemental abundances, and ionization structure; study the behavior of emission features as a function of binary orbit; and test and improve models of X-ray line emission developed by us over the past decade. We will gain insight on both the geometry of the accretion flow and on the evolutionary history of LMXBs.

  18. Spectroscopy of Low Mass X-Ray Binaries: New Insights into Accretion

    NASA Technical Reports Server (NTRS)

    Vrtilek, Saeqa Dil; Mushotzky, Richard F. (Technical Monitor)

    2002-01-01

    This project is to observe two low mass X-ray binaries, chosen for their X-ray brightness, low column density, and diversity of accretion behavior. The high spectral resolution of the RGS, the broad energy range and tremendous collecting power of EPIC, and simultaneous optical monitoring with the OM are particularly well-suited to these studies. The second of two objects was not observed until September of 2002. Data analysis for the new observation is underway. over the next year we will: investigate the physical conditions of the emitting gas using emission and recombination line diagnostics to determine temperatures, densities, elemental abundances, and ionization structure; study the behavior of emission features as a function of binary orbit; and test and improve models of X-ray line emission developed by us over the past decade. We will gain insight on both the geometry of the accretion flow and on the evolutionary history of LMXBs.

  19. Period Derivative of the M15 X-Ray Binary AC211/X2127+119

    NASA Technical Reports Server (NTRS)

    Homer, L.; Charles, P. A.

    1998-01-01

    We have combined Rossi X-ray Timing Explorer observations of X2127+119, the low-mass X-ray binary in the globular cluster M15, with archival X-ray lightcurves to study the stability of the 17.1 hr orbital period. We find that the data cannot be fit by the Ilovaisky ephemeris, and requires either a 7.sigma change to the period or a period derivative P prime/P approximately 9 x 10(exp -7)/yr. Given its remarkably low L(sub X)/L(sub opt) such a P prime lends support to models that require super-Eddington mass transfer in a q approximately 1 binary.

  20. The USA experiment on the Argos Satellite: A low cost instrument for timing x-ray binaries

    SciTech Connect

    Wood, K.S.; Fritz, G.; Hertz, P.; Johnson, W.N.; Lovelette, M.N.; Wolff, M.T. ); Bloom, E.; Godfrey, G.; Hanson, J.; Michelson, P.; Taylor, R.; Wen, H. )

    1994-07-05

    The Unconventional Stellar Aspect (USA) experiment to be launched in September 1995 on the Advanced Research and Global Observations Satellite (ARGOS) is a low-cost, quick---yet scientifically ambitious---x-ray timing experiment. It is designed for the dual purpose of scientific research in x-ray timing and time resolved spectroscopy and also for exploration of applications of x-ray sensor technology. Bright galactic x-ray binaries are used simultaneously for both scientific and applied objectives.

  1. Relativistic Astrophysics in Black Hole and Low-Mass Neutron Star X-ray Binaries

    NASA Technical Reports Server (NTRS)

    2000-01-01

    During the five-year period, our study of "Relativistic Astrophysics in Black Hole and Low-Mass Neutron Star X-ray Binaries" has been focused on the following aspects: observations, data analysis, Monte-Carlo simulations, numerical calculations, and theoretical modeling. Most of the results of our study have been published in refereed journals and conference presentations.

  2. Accretion states in X-ray binaries and their connection to GeV emission

    NASA Astrophysics Data System (ADS)

    Koerding, Elmar

    Accretion onto compact objects is intrinsically a multi-wavelength phenomenon: it shows emis-sion components visible from the radio to GeV bands. In X-ray binaries one can well observe the evolution of a single source under changes of the accretion rate and thus study the interplay between the different emission components.I will introduce the phenomenology of X-ray bina-ries and their accretion states and present our current understanding of the interplay between the optically thin and optically thick part of the accretion flow and the jet.The recent detection of the Fermi Large Area Telescope of a variable high-energy source coinciding with the position of the x-ray binary Cygnus X-3 will be presented. Its identification with Cygnus X-3 has been secured by the detection of its orbital period in gamma rays, as well as the correlation of the LAT flux with radio emission from the relativistic jets of Cygnus X-3. This will be interpreted in the context of the accretion states of the X-ray binary.

  3. Extremely fast orbital decay of the black hole X-ray binary Nova Muscae 1991

    NASA Astrophysics Data System (ADS)

    González Hernández, J. I.; Suárez-Andrés, L.; Rebolo, R.; Casares, J.

    2017-02-01

    We present new medium-resolution spectroscopic observations of the black hole X-ray binary Nova Muscae 1991 taken with X-Shooter spectrograph installed at the 8.2-m VLT telescope. These observations allow us to measure the time of inferior conjunction of the secondary star with the black hole in this system that, together with previous measurements, yield an orbital period decay of dot{P}=-20.7± 12.7 ms yr-1 (-24.5 ± 15.1 μs per orbital cycle). This is significantly faster than those previously measured in the other black hole X-ray binaries A0620-00 and XTE J1118+480. No standard black hole X-ray binary evolutionary model is able to explain this extremely fast orbital decay. At this rate, the secondary star would reach the event horizon (as given by the Schwarzschild radius of about 32 km) in roughly 2.7 Myr. This result has dramatic implications on the evolution and lifetime of black hole X-ray binaries.

  4. A1540-53, an eclipsing X-ray binary pulsator

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Swank, J. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Saba, J. R.; Serlemitsos, P. J.

    1977-01-01

    An eclipsing X-ray binary pulsator consistent with the location of A1540-53 was observed. The source pulse period was 528.93 plus or minus 0.10 seconds. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 deg plus or minus 3 deg and the 4 h transition to and from eclipse suggest an early type, giant or supergiant, primary star.

  5. Catalogue of cataclysmic binaries, low-mass X-ray binaries and related objects (Seventh edition)

    NASA Astrophysics Data System (ADS)

    Ritter, H.; Kolb, U.

    2003-06-01

    The catalogue lists coordinates, apparent magnitudes, orbital parameters, and stellar parameters of the components and other characteristc properties of 472 cataclysmic binaries, 71 low-mass X-ray binaries and 113 related objects with known or suspected orbital periods together with a comprehensive selection of the relevant recent literature. In addition, the catalogue contains a list of references to published finding charts for 635 of the 656 objects, and a cross-reference list of alias object designations. Literature published before 1 January 2003 has, as far as possible, been taken into account. All data can be accessed via the dedicated catalogue webpage at http://www.mpa-garching.mpg.de/RKcat/ and http://physics.open.ac.uk/RKcat/ and at CDS via anonymous ftp to cdsarc.u-strasbg.fr (30.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/404/301. We will update the information given on the catalogue webpage regularly, initially every six months.

  6. Multi-wavelength Study of the Be/X-Ray Binary MXB 0656-072

    NASA Astrophysics Data System (ADS)

    Yan, Jingzhi; Zurita Heras, Juan Antonio; Chaty, Sylvain; Li, Hui; Liu, Qingzhong

    2012-07-01

    We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the Hα emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

  7. MULTI-WAVELENGTH STUDY OF THE Be/X-RAY BINARY MXB 0656-072

    SciTech Connect

    Yan Jingzhi; Li Hui; Liu Qingzhong; Zurita Heras, Juan Antonio; Chaty, Sylvain E-mail: hli@pmo.ac.cn E-mail: juan-antonio.zurita-heras@cea.fr

    2012-07-01

    We present and analyze the optical photometric and spectroscopic data of the Be/X-ray binary MXB 0656-072 from 2006 to 2009. A 101.2 day orbital period is found, for the first time, from the present public X-ray data (Swift/BAT and RXTE/ASM). The anti-correlation between the H{alpha} emission and the UBV brightness of MXB 0656-072 during our 2007 observations indicates that a mass ejection event took place in the system. After the mass ejection, a low-density region might develop around the Oe star. With the outward motion of the circumstellar disk, the outer part of the disk interacted with the neutron star around its periastron passage and a series of X-ray outbursts were triggered between MJD 54350 and MJD 54850. The Proportional Counter Array-HEXTE spectra during the 2007-2008 X-ray outbursts could be well fitted by a cutoff power law with low-energy absorption, together with an iron line around 6.4 keV, and a broad cyclotron resonance feature around 30 keV. The same variability of the soft and hard X-ray colors in 2.3-21 keV indicated that there were no overall changes in the spectral shape during the X-ray outbursts, which might only be connected with the changes of the mass accretion rate onto the neutron star.

  8. Evolution of Intermediate-mass X-Ray Binaries Driven by the Magnetic Braking of AP/BP Stars. I. Ultracompact X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Cong; Podsiadlowski, Philipp

    2016-10-01

    It is generally believed that ultracompact X-ray binaries (UCXBs) evolved from binaries consisting of a neutron star accreting from a low-mass white dwarf (WD) or helium star where mass transfer is driven by gravitational radiation. However, the standard WD evolutionary channel cannot produce the relatively long-period (40-60 minutes) UCXBs with a high time-averaged mass-transfer rate. In this work, we explore an alternative evolutionary route toward UCXBs, where the companions evolve from intermediate-mass Ap/Bp stars with an anomalously strong magnetic field (100-10,000 G). Including the magnetic braking caused by the coupling between the magnetic field and an irradiation-driven wind induced by the X-ray flux from the accreting component, we show that intermediate-mass X-ray binaries (IMXBs) can evolve into UCXBs. Using the MESA code, we have calculated evolutionary sequences for a large number of IMXBs. The simulated results indicate that, for a small wind-driving efficiency f = 10-5, the anomalous magnetic braking can drive IMXBs to an ultra-short period of 11 minutes. Comparing our simulated results with the observed parameters of 15 identified UCXBs, the anomalous magnetic braking evolutionary channel can account for the formation of seven and eight sources with f = 10-3, and 10-5, respectively. In particular, a relatively large value of f can fit three of the long-period, persistent sources with a high mass-transfer rate. Though the proportion of Ap/Bp stars in intermediate-mass stars is only 5%, the lifetime of the UCXB phase is ≳2 Gyr, producing a relatively high number of observable systems, making this an alternative evolutionary channel for the formation of UCXBs.

  9. The X-Ray Binary Population of the Nearby Dwarf Starburst Galaxy IC 10: Variable and Transient X-Ray Sources

    NASA Astrophysics Data System (ADS)

    Laycock, Silas; Cappallo, Rigel; Williams, Benjamin F.; Prestwich, Andrea; Binder, Breanna; Christodoulou, Dimitris M.

    2017-02-01

    We have monitored the Cassiopeia dwarf galaxy (IC 10) in a series of 10 Chandra ACIS-S observations to capture its variable and transient X-ray source population, which is expected to be dominated by High Mass X-ray Binaries (HMXBs). We present a sample of 21 X-ray sources that are variable between observations at the 3σ level, from a catalog of 110 unique point sources. We find four transients (flux variability ratio greater than 10) and a further eight objects with ratios >5. The observations span the years 2003–2010 and reach a limiting luminosity of >1035 erg s‑1, providing sensitivity to X-ray binaries in IC 10 as well as flare stars in the foreground Milky Way. The nature of the variable sources is investigated from light curves, X-ray spectra, energy quantiles, and optical counterparts. The purpose of this study is to discover the composition of the X-ray binary population in a young starburst environment. IC 10 provides a sharp contrast in stellar population age (<10 My) when compared to the Magellanic Clouds (40–200 My) where most of the known HMXBs reside. We find 10 strong HMXB candidates, 2 probable background Active Galactic Nuclei, 4 foreground flare-stars or active binaries, and 5 not yet classifiable sources. Complete classification of the sample requires optical spectroscopy for radial velocity analysis and deeper X-ray observations to obtain higher S/N spectra and search for pulsations. A catalog and supporting data set are provided.

  10. Blue stragglers and X -ray binaries in open clusters: An observational study of alternative pathways in stellar evolution

    NASA Astrophysics Data System (ADS)

    Gosnell, Natalie Marie

    Membership studies of evolved open clusters reveal many alternative pathway stellar products whose evolution cannot be explained using single-star evolutionary models. These stars are neither rare nor anomalous, and in fact are a common occurrence in cluster populations. The goal of this thesis is to investigate the origin and evolutionary pathways of such stars through the careful study of X-ray binaries in NGC 6819 and white dwarf (WD) companions of mass transfer-formed blue straggler stars (BSSs) in NGC 188. I present the first X-ray study of the intermediate-age open cluster NGC 6819, using observations from XMM-Newton. This study of NGC 6819 is part of a systematic survey to investigate the relationship between the number of X-ray sources and cluster dynamics in the regime of massive open clusters. Of the 12 X-ray sources within the half-light radius of NGC 6819, four sources challenge single-star evolutionary models, including a candidate quiescent low-mass X-ray binary. Next, I present the first results from a Hubble Space Telescope (HST) far-ultraviolet (FUV) campaign to search for WD companions of BSSs as indicators of mass transfer formation. I find direct observational detections of young (< 250 Myr), hot WD companions in three BSS binaries. Their presence in a well-studied cluster environment allows for unparalleled constraints on the pre-mass transfer system. I outline potential formation timelines for these three BSSs, which all formed through recent mass transfer. Finally, I use HST photometry of the complete NGC 188 BSS population to place limits on the mass transfer BSS formation frequency. Comparison of the observations with models for BSS FUV emission reveals seven WD companions with temperatures greater than 11,000 K. The location of the young BSSs on an optical color-magnitude diagram suggests that using single-star evolutionary models to age luminous BSSs may be problematic. Considering other formation scenarios, the total mass transfer

  11. X-Ray and Optical Observations of the Unique Binary System HD 49798/RX J0648.0-4418

    NASA Astrophysics Data System (ADS)

    Mereghetti, S.; La Palombara, N.; Tiengo, A.; Pizzolato, F.; Esposito, P.; Woudt, P. A.; Israel, G. L.; Stella, L.

    2011-08-01

    We report the results of XMM-Newton observations of HD 49798/RX J0648.0-4418, the only known X-ray binary consisting of a hot sub-dwarf and a white dwarf. The white dwarf rotates very rapidly (P = 13.2 s) and has a dynamically measured mass of 1.28 ± 0.05 M sun. Its X-ray emission consists of a strongly pulsed, soft component, well fit by a blackbody with kT BB ~ 40 eV, accounting for most of the luminosity, and a fainter hard power-law component (photon index ~1.6). A luminosity of ~1032 erg s-1 is produced by accretion onto the white dwarf of the helium-rich matter from the wind of the companion, which is one of the few hot sub-dwarfs showing evidence of mass loss. A search for optical pulsations at the South African Astronomical Observatory 1.9 m telescope gave negative results. X-rays were also detected during the white dwarf eclipse. This emission, with luminosity 2 × 1030 erg s-1, can be attributed to HD 49798 and represents the first detection of a hot sub-dwarf star in the X-ray band. HD 49798/RX J0648.0-4418 is a post-common-envelope binary which most likely originated from a pair of stars with masses ~8-10 M sun. After the current He-burning phase, HD 49798 will expand and reach the Roche lobe, causing a higher accretion rate onto the white dwarf which can reach the Chandrasekhar limit. Considering the fast spin of the white dwarf, this could lead to the formation of a millisecond pulsar. Alternatively, this system could be a Type Ia supernova progenitor with the appealing characteristic of a short time delay, being the descendent of relatively massive stars.

  12. Interference as an Origin of the Peaked Noise in Accreting X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Veledina, Alexandra

    2016-12-01

    We propose a physical model for the peaked noise in the X-ray power density spectra of accreting X-ray binaries. We interpret its appearance as an interference of two Comptonization continua: one coming from the upscattering of seed photons from the cold thin disk and the other fed by the synchrotron emission of the hot flow. Variations of both X-ray components are caused by fluctuations in mass accretion rate, but there is a delay between them corresponding to the propagation timescale from the disk Comptonization radius to the region of synchrotron Comptonization. If the disk and synchrotron Comptonization are correlated, the humps in the power spectra are harmonically related and the dips between them appear at frequencies related as odd numbers 1:3:5. If they are anti-correlated, the humps are related as 1:3:5, but the dips are harmonically related. Similar structures are expected to be observed in accreting neutron star binaries and supermassive black holes. The delay can be easily recovered from the frequency of peaked noise and further used to constrain the combination of the viscosity parameter and disk height-to-radius ratio α(H/R)2 of the accretion flow. We model multi-peak power spectra of black hole X-ray binaries GX 339-4 and XTE J1748-288 to constrain these parameters.

  13. Activities of X-ray binaries accompanied by a neutron star with weak magnetic field: Cir X-1, Aql X-1 and 4U 1608-52

    NASA Astrophysics Data System (ADS)

    Matsuoka, Masaru; Mihara, Tatehiro; Asai, Kazumi

    This paper is presented on X-ray activities of X-ray binaries accompanied by a neutron star with weak magnetic field. Neutron star low mass X-ray binaries (NS-LMXBs) have been well studied so far, but there are still unknown problems concerning activities of outbursts and X-ray spectral features. We can define the soft and hard states which show different spectra created from each disk structure. These states depend on the gas accretion rate causing viscosity change in the disk, whereas we have pointed out an importance of magnetic field in NS-LMXB for X-ray activities (Matsuoka & Asai 2013). Thus, we have obtained decay features occurred by a propeller effect for Aql X-1 and 4U1608-52, and thus, we have defined the propeller effect levels of these sources (Asai et al. 2013). A companion star of Cir X-1 is a star of B5~A0 type, but it has X-ray spectral feature similar to NS-LMXB as well as it produced type I X-ray bursts. A long history over 40 years of X-ray observations has provided that Cir X-1 X-ray intensities have many varieties from continuous variable fluxes with Z-type feature of NS-LMXB to recurrent outburst fluxes with Atoll-type feature on a time scale of years. Recent MAXI observations have revealed a strange sudden decay feature in some outbursts. It is difficult to explain this decay feature by the simple picture which causes by ordinary mechanisms known in NS-LMXB such as a state transition, a propeller effect and a brink due to disk irradiation (Powell et al. 2007). Therefore, we introduced new type of instability of the accretion disk in relation to stellar wind stripping effect (Asai et al. 2014) which may be common to a system consisting of a compact star and an ordinary massive star.

  14. Orbital period decay of compact black hole X-ray binaries: the influence of circumbinary disks?

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Cong; Li, Xiang-Dong

    2015-11-01

    Context. Recently, compact black hole X-ray binaries XTE J 1118+480 and A0620-00 have been reported to be experiencing a fast orbital period decay, which is two orders of magnitude higher than expected with gravitational wave radiation. Magnetic braking of an Ap/Bp star has been suggested to account for the period change when the surface magnetic field of the companion star Bs ≳ 104 G. However, our calculation indicates that anomalous magnetic braking cannot significantly contribute to the large orbital period decay rates observed in these two sources even if Bs ≳ 104 G. Aims: Observations have provided evidence that circumbinary disks around two compact black hole X-ray binaries may exist. Our analysis shows that, for some reasonable parameters, tidal torque between the circumbinary disk and the binary can efficiently extract the orbital angular momentum from the binary, and result in a large orbital period change rate. Methods: Based on the circumbinary disk model, we simulate the evolution of XTE J 1118+480 via a stellar evolution code. Results: Our computations are approximatively in agreement with the observed data (the masses of two components, donor star radius, orbital period, and orbital period derivative). Conclusions: The mass transfer rate and circumbinary disk mass are obviously far greater than the inferred values from observations. Therefore, it seems that the circumbinary disk is unlikely to be the main cause of the rapid orbital decay observed in some compact black hole X-ray binaries.

  15. Photometric and Polarimetric Observations of Be/X-Ray and Be/Gamma-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Moritani, Y.; Akitaya, H.; Ebisuda, N.; Itoh, R.; Kanda, Y.; Kawabata, M.; Kawaguchi, K.; Mori, K.; Nakaoka, T.; Ohashi, Y.; Takaki, K.; Ueno, I.; Ui, T.; Urano, T.; Yoshida, M.

    2016-11-01

    Be/X-ray and Be/γ-ray binaries are systems comprised of a Be star and a compact object. In these systems, the Be disk plays an important role in their high-energy activities through the interaction with the compact object. Because of highly eccentric orbits, the interaction depends on the orbital phase in Be/X and Be/γ-ray binaries. Such interaction affects the Be disk structure, causing photometric and polarimetric variabilities. In order to search for photometric and polatimetric variability in Be/X-ray and Be/γ-ray binaries, we have monitored several systems with the polarimeter attached to Hiroshima 1.5m Kanata telescope, Japan. Our two-year monitor finds that some programmed systems show photometric variations and a few systems show polatimatric variabilities.

  16. X-ray variability in Galactic high-mass black hole binaries

    NASA Astrophysics Data System (ADS)

    Axelsson, Magnus

    The stars of the night sky can to the naked eye appear to be steady and unchanging, apart from the twinkling created by air moving in the atmosphere. However, when viewed in X-rays, the sky is far from constant, with detectable changes occurring on very short timescales. Black hole X-ray binaries are strong sources of X-rays. These systems contain a star and a black hole in orbit around each other. As matter from the companion star is accreted by the black hole, large amounts of gravitational energy are released, giving rise to strong X-ray emission. The accretion flow close to a black hole is characterized by strong gravity, high-energy radiation and variability on timescales down to milliseconds. These systems allow us to probe physics under conditions we cannot recreate in a laboratory, and provide some of the strongest observational indications of the existence of black holes. Temporal analysis is a powerful diagnostic of the geometry and physical processes of this environment. The bulk of this thesis concerns studies of the rapid variability of perhaps the most well-known of all black hole binaries: Cygnus X-1. By tapping into the large amount of archival data available, a systematic study of the variability, in the form of the power spectrum, is conducted. The results show that timing studies can indeed give valuable information on the emission mechanisms and accretion geometry. Tying characteristic frequencies to effects predicted by general relativity directly gives information about the parameters of the compact object. Using these results, the past evolution of the binary system is studied. In addition, results from temporal analysis of the possible black hole binary Cygnus X-3 are presented. The study of X-ray variability covers timescales from years to seconds, and shows that while temporal analysis provides clues to this complex system, it does not provide immediate insight into the accretion geometry, or the nature of the compact object

  17. Selection effects on the orbital period distribution of Low Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Arur, Kavitha; Maccarone, Tom

    2017-01-01

    Observations show a lack of Low Mass Black Hole Binaries with orbital periods below 4 hours. While it is known that Black Hole Binaries (BHBs) tend to have lower peak luminosities in outburst compared to their Neutron Star counterparts, it is unclear if selection effects can account for the difference in the numbers. Studying the effect of these selection biases is important for binary population studies. Here we report on the implications for the inferred orbital period distribution of these BHBs after a simulation that accounts for extinction of the optical counterpart, absorption of X-ray counts and detectability of the outburst.

  18. Quantitative measurement of binary liquid distributions using multiple-tracer x-ray fluorescence and radiography

    SciTech Connect

    Halls, Benjamin R.; Meyer, Terrence R.; Kastengren, Alan L.

    2015-01-01

    The complex geometry and large index-of-refraction gradients that occur near the point of impingement of binary liquid jets present a challenging environment for optical interrogation. A simultaneous quadruple-tracer x-ray fluorescence and line-of-sight radiography technique is proposed as a means of distinguishing and quantifying individual liquid component distributions prior to, during, and after jet impact. Two different pairs of fluorescence tracers are seeded into each liquid stream to maximize their attenuation ratio for reabsorption correction and differentiation of the two fluids during mixing. This approach for instantaneous correction of x-ray fluorescence reabsorption is compared with a more time-intensive approach of using stereographic reconstruction of x-ray attenuation along multiple lines of sight. The proposed methodology addresses the need for a quantitative measurement technique capable of interrogating optically complex, near-field liquid distributions in many mixing systems of practical interest involving two or more liquid streams.

  19. Inclination Angles of Black Hole X-Ray Binaries Manifest Strong Gravity around Black Holes

    NASA Technical Reports Server (NTRS)

    Zhang, S. N.; Zhang, Xiao-Ling; Yao, Yangsen

    2002-01-01

    System inclination angles have been determined for about 15 X-ray binaries, in which stellar mass black holes are considered to exist. These inclination angles range between 25 degrees and 80 degrees, but peaked between 60-70 degrees. This peak is not explained in the frame work of Newtonian gravity. However, this peak is reproduced naturally if we model the observed X-ray radiations as being produced in the accretion disks very close to the black hole horizons, where the extremely strong general and special relativistic effects, caused by the extremely strong gravity near the black hole horizons, modify the local radiation significantly as the X-rays propagate to the remote observer. Therefore the peak of the inclination angle distribution provides evidence or strong gravity around stellar mass black holes.

  20. The peculiar high-mass X-ray binary 1ES 1210-646

    NASA Astrophysics Data System (ADS)

    Masetti, N.; Landi, R.; Sguera, V.; Capitanio, F.; Bassani, L.; Bazzano, A.; Bird, A. J.; Malizia, A.; Palazzi, E.

    2010-02-01

    Using data collected with the BeppoSAX, INTEGRAL and Swift satellites, we report and discuss the results of a study on the X-ray emission properties of the X-ray source 1ES 1210-646, recently classified as a high-mass X-ray binary through optical spectroscopy. This is the first in-depth analysis of the X-ray spectral characteristics of this source. We found that the flux of 1ES 1210-646 varies by a factor of ~3 on a timescale of hundreds of seconds and by a factor of at least 10 among observations acquired over a time span of several months. The X-ray spectrum of 1ES 1210-646 is described using a simple powerlaw shape or, in the case of INTEGRAL data, with a blackbody plus powerlaw model. Spectral variability is found in connection with different flux levels of the source. A strong and transient iron emission line with an energy of ~6.7 keV and an equivalent width of ~1.6 keV is detected when the source is found at an intermediate flux level. The line strength seems to be tied to the orbital motion of the accreting object, as this feature is only apparent at the periastron. Although the X-ray spectral description we find for the 1ES 1210-646 emission is quite atypical for a high-mass X-ray binary, the multiwavelegth information available for this object leads us to confirm this classification. The results presented here allow us instead to definitely rule out the possibility that 1ES 1210-646 is a (magnetic) cataclysmic variable as proposed previously and, in a broader sense, a white dwarf nature for the accretor is disfavoured. X-ray spectroscopic data actually suggest a neutron star with a low magnetic field as the accreting object in this system. Partly based on X-ray observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA.

  1. Simultaneous X-Ray and Radio Observations of the Unusual Binary LSI + 61 deg 303

    NASA Technical Reports Server (NTRS)

    Harrison, Fiona A.; Leahy, Denis A.; Waltman, Elizabeth

    1996-01-01

    We present simultaneous 0.5 - 10 keV X-ray and two-frequency radio observations at 2.25 and 8.3 GHz of the unusual binary system LSI + 61 deg. 303. This system was observed twice in a single binary orbit by the ASCA satellite, and monitored daily at two radio frequencies during the same orbital cycle with the Greenbank Interferometer. During the first ASCA observation the source was detected with a 1 - 10 keV luminosity 3.6 x 10(exp 33) (d/2.0 kpc)(exp 2) erg 1/s and during the second at a similar level with evidence for a decrease in average flux of 30%. During the first pointing the radio source was at a quiescent 8 GHz flux level of 30 mJy while during the second the radio flux was rising dramatically with an average value of 100 mJy. No variability is seen in the X-ray flux during the first pointing, but during the second the flux is variable by approx. 50% on timescales of approx. 30 minutes. No pulsations are seen in either X-ray observation with an upper limit on pulsed flux of 20%. The low X-ray luminosity and lack of observed pulsations indicate that accretion onto a neutron star surface is not the origin for the high-energy emission. Rather, the X-rays must result either from accreted matter which is stopped at the magnetosphere because the magnetospheric boundry is rotating at super-Keplerian rates or due to a shock formed in the interaction of the dense wind of the Be star companion and a moderately young pulsar. We derive a required pulsar spin down luminosity of approx. 10(exp 37) erg 1/s, and argue that the shock model more easily explains the observed X-ray radio observations.

  2. INTEGRAL/IBIS observations of a hard X-ray outburst in high-mass X-ray binary 4U 2206+54

    NASA Astrophysics Data System (ADS)

    Wang, W.

    2010-09-01

    Aims: 4U 2206+54 is a wind-fed high-mass X-ray binary with a main-sequence donor star. The nature of its compact object has been recently identified as a slow-pulsation magnetized neutron star. Methods: INTEGRAL/IBIS observations have a long-term hard X-ray monitoring of 4U 2206+54 and detected a hard X-ray outburst around 15 December 2005 combined with the RXTE/ASM data. Results: The hard X-ray outburst had a double-flare feature with a duration of ~2 days. The first flare showed a fast rise and long-term decaying light curve about 15 h with a peak luminosity of ~4 × 1036 erg s-1 from 1.5-12 keV and a hard spectrum (only significantly seen above 5 keV). The second one had the mean hard X-ray luminosity of 1.3 × 1036 erg s-1 from 20-150 keV with a modulation period at ~5550 s which is the pulse period of the neutron star in 4U 2206+54. Its hard X-ray spectrum from 20-300 keV can be fitted by a broken power-law model with the photon indexes Γ1 ~ 2.3, and Γ2 ~ 3.3, and the break energy is Eb ~ 31 keV or by a bremsstrahlung model of kT ~ 23 keV. Conclusions: We suggest that the hard X-ray flare could be induced by suddenly enhanced accreting dense materials from stellar winds hitting the polar cap region of the neutron star. This hard X-ray outburst may be a link to supergiant fast X-ray transients though 4U 2206+54 has a different type of companion.

  3. TRACING THE REVERBERATION LAG IN THE HARD STATE OF BLACK HOLE X-RAY BINARIES

    SciTech Connect

    De Marco, B.; Ponti, G.; Nandra, K.; Muñoz-Darias, T.

    2015-11-20

    We report results obtained from a systematic analysis of X-ray lags in a sample of black hole X-ray binaries, with the aim of assessing the presence of reverberation lags and studying their evolution during outburst. We used XMM-Newton and simultaneous Rossi X-ray Timing Explorer (RXTE) observations to obtain broadband energy coverage of both the disk and the hard X-ray Comptonization components. In most cases the detection of reverberation lags is hampered by low levels of variability-power signal-to-noise ratio (typically when the source is in a soft state) and/or short exposure times. The most detailed study was possible for GX 339-4 in the hard state, which allowed us to characterize the evolution of X-ray lags as a function of luminosity in a single source. Over all the sampled frequencies (∼0.05–9 Hz), we observe the hard lags intrinsic to the power-law component, already well known from previous RXTE studies. The XMM-Newton soft X-ray response allows us to detail the disk variability. At low frequencies (long timescales) the disk component always leads the power-law component. On the other hand, a soft reverberation lag (ascribable to thermal reprocessing) is always detected at high frequencies (short timescales). The intrinsic amplitude of the reverberation lag decreases as the source luminosity and the disk fraction increase. This suggests that the distance between the X-ray source and the region of the optically thick disk where reprocessing occurs gradually decreases as GX 339-4 rises in luminosity through the hard state, possibly as a consequence of reduced disk truncation.

  4. Energy Feedback from X-ray Binaries in the Early Universe

    NASA Technical Reports Server (NTRS)

    Fragos, T.; Lehmer, B..; Naoz, S.; Zezas, A.; Basu-Zych, A.

    2013-01-01

    X-ray photons, because of their long mean-free paths, can easily escape the galactic environments where they are produced, and interact at long distances with the intergalactic medium, potentially having a significant contribution to the heating and reionization of the early universe. The two most important sources of X-ray photons in the universe are active galactic nuclei (AGNs) and X-ray binaries (XRBs). In this Letter we use results from detailed, large scale population synthesis simulations to study the energy feedback of XRBs, from the first galaxies (z (redshift) approximately equal to 20) until today.We estimate that X-ray emission from XRBs dominates over AGN at z (redshift) greater than or approximately equal to 6-8. The shape of the spectral energy distribution of the emission from XRBs shows little change with redshift, in contrast to its normalization which evolves by approximately 4 orders of magnitude, primarily due to the evolution of the cosmic star-formation rate. However, the metallicity and the mean stellar age of a given XRB population affect significantly its X-ray output. Specifically, the X-ray luminosity from high-mass XRBs per unit of star-formation rate varies an order of magnitude going from solar metallicity to less than 10% solar, and the X-ray luminosity from low-mass XRBs per unit of stellar mass peaks at an age of approximately 300 Myr (million years) and then decreases gradually at later times, showing little variation for mean stellar ages 3 Gyr (Giga years, or billion years). Finally, we provide analytical and tabulated prescriptions for the energy output of XRBs, that can be directly incorporated in cosmological simulations.

  5. High-Frequency X-Ray Oscillations and X-Ray Spectral Evolution in Galactic Black Hole Binaries

    NASA Astrophysics Data System (ADS)

    Remillard, R. A.; Morgan, E. H.; Muno, M.

    2002-12-01

    There are now 5 Galactic black hole candidates that have exhibited quasi-periodic oscillations (QPO) in X-rays in the range of 67 to 300 Hz. The rms amplitudes are near 1 % of the average flux, and in two cases there are significant changes in the QPO frequency. The short timescales and origin in X-rays suggest that these QPOs signify inner accretion disk oscillations rooted in General Relativity, but the particular mechanism is uncertain. For two of these cases, GRO J1655-40 and GRS 1915+105, we trace the conditions under which these QPOs appear in terms of the division of luminosity between the X-ray components due to the accretion disk and the hard X-ray power law. In this context, the fast QPOs are most likely to occur when there is high luminosity in both the disk and the X-ray power-law component. On the other hand, the QPOs are not seen when the X-ray spectrum resembles either a pure disk or a dominant power-law component associated with a radio jet. The results imply a closer kinship for these QPOs than might be concluded from considerations of the gross shape of the X-ray spectrum.

  6. The X-Ray Luminosity Functions of Field Low-Mass X-Ray Binaries in Early-Type Galaxies: Evidence for a Stellar Age Dependence

    NASA Technical Reports Server (NTRS)

    Lehmer, B. D.; Berkeley, M.; Zezas, A.; Alexander, D. M.; Basu-Zych, A.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Hornschemeier, A. E.; Kalogera, V.; Ptak, A.; Sivakoff, G. R.; Tzanavaris, P.; Yukita, M.

    2014-01-01

    We present direct constraints on how the formation of low-mass X-ray binary (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The luminosity-weighted stellar ages of our sample span approximately equal to 3-10 Gyr. X-ray binary population synthesis models predict that the field LMXBs associated with younger stellar populations should be more numerous and luminous per unit stellar mass than older populations due to the evolution of LMXB donor star masses. Crucially, the combination of deep Chandra and HST observations allows us to test directly this prediction by identifying and removing counterparts to X-ray point sources that are unrelated to the field LMXB populations, including LMXBs that are formed dynamically in globular clusters, Galactic stars, and background AGN/galaxies. We find that the "young" early-type galaxy NGC 3384 (approximately equals 2-5 Gyr) has an excess of luminous field LMXBs (L(sub x) approximately greater than (5-10) × 10(exp 37) erg s(exp -1)) per unit K-band luminosity (L(sub K); a proxy for stellar mass) than the "old" early-type galaxies NGC 3115 and 3379 (approximately equals 8-10 Gyr), which results in a factor of 2-3 excess of L(sub X)/L(sub K) for NGC 3384. This result is consistent with the X-ray binary population synthesis model predictions; however, our small galaxy sample size does not allow us to draw definitive conclusions on the evolution field LMXBs in general. We discuss how future surveys of larger galaxy samples that combine deep Chandra and HST data could provide a powerful new benchmark for calibrating X-ray binary population synthesis models.

  7. The youngest known X-ray binary: Circinus X-1 and its natal supernova remnant

    SciTech Connect

    Heinz, S.; Sell, P.; Fender, R. P.; Jonker, P. G.; Brandt, W. N.; Calvelo-Santos, D. E.; Tzioumis, A. K.; Nowak, M. A.; Schulz, N. S.; Wijnands, R.; Van der Klis, M.

    2013-12-20

    Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to exist in our Galaxy. We report the discovery of the natal supernova remnant of the accreting neutron star Circinus X-1, which places an upper limit of t < 4600 yr on its age, making it the youngest known X-ray binary and a unique tool to study accretion, neutron star evolution, and core-collapse supernovae. This discovery is based on a deep 2009 Chandra X-ray observation and new radio observations of Circinus X-1. Circinus X-1 produces type I X-ray bursts on the surface of the neutron star, indicating that the magnetic field of the neutron star is small. Thus, the young age implies either that neutron stars can be born with low magnetic fields or that they can rapidly become de-magnetized by accretion. Circinus X-1 is a microquasar, creating relativistic jets that were thought to power the arcminute-scale radio nebula surrounding the source. Instead, this nebula can now be attributed to non-thermal synchrotron emission from the forward shock of the supernova remnant. The young age is consistent with the observed rapid orbital evolution and the highly eccentric orbit of the system and offers the chance to test the physics of post-supernova orbital evolution in X-ray binaries in detail for the first time.

  8. The Youngest Known X-Ray Binary: Circinus X-1 and Its Natal Supernova Remnant

    NASA Astrophysics Data System (ADS)

    Heinz, S.; Sell, P.; Fender, R. P.; Jonker, P. G.; Brandt, W. N.; Calvelo-Santos, D. E.; Tzioumis, A. K.; Nowak, M. A.; Schulz, N. S.; Wijnands, R.; van der Klis, M.

    2013-12-01

    Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to exist in our Galaxy. We report the discovery of the natal supernova remnant of the accreting neutron star Circinus X-1, which places an upper limit of t < 4600 yr on its age, making it the youngest known X-ray binary and a unique tool to study accretion, neutron star evolution, and core-collapse supernovae. This discovery is based on a deep 2009 Chandra X-ray observation and new radio observations of Circinus X-1. Circinus X-1 produces type I X-ray bursts on the surface of the neutron star, indicating that the magnetic field of the neutron star is small. Thus, the young age implies either that neutron stars can be born with low magnetic fields or that they can rapidly become de-magnetized by accretion. Circinus X-1 is a microquasar, creating relativistic jets that were thought to power the arcminute-scale radio nebula surrounding the source. Instead, this nebula can now be attributed to non-thermal synchrotron emission from the forward shock of the supernova remnant. The young age is consistent with the observed rapid orbital evolution and the highly eccentric orbit of the system and offers the chance to test the physics of post-supernova orbital evolution in X-ray binaries in detail for the first time.

  9. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    SciTech Connect

    Parkin, E. R.; Sim, S. A. E-mail: s.sim@qub.ac.uk

    2013-04-20

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L{sub X}, remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L{sub X}/L{sub bol}). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  10. A Statistical Approach to Identifying Compact Objects in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Vrtilek, Saeqa D.

    2013-04-01

    A standard approach towards statistical inferences in astronomy has been the application of Principal Components Analysis (PCA) to reduce dimensionality. However, for non-linear distributions this is not always an effective approach. A non-linear technique called ``diffusion maps" (Freema \\eta 2009; Richard \\eta 2009; Lee \\& Waterman 2010), a robust eigenmode-based framework, allows retention of the full ``connectivity" of the data points. Through this approach we define the highly non-linear geometry of X-ray binaries in a color-color-intensity diagram in an efficient and statistically sound manner providing a broadly applicable means of distinguishing between black holes and neutron stars in Galactic X-ray binaries.

  11. Probing the X-Ray Binary Populations of the Ring Galaxy NGC 1291

    NASA Technical Reports Server (NTRS)

    Luo, B.; Fabbiano, G.; Fragos, T.; Kim, D. W.; Belczynski, K.; Brassington, N. J.; Pellegrini, S.; Tzanavaris, P.; Wang, J.; Zezas, A.

    2012-01-01

    We present Chandra studies of the X-ray binary (XRB) populations in the bulge and ring regions of the ring galaxy NGC 1291. We detect 169 X-ray point sources in the galaxy, 75 in the bulge and 71 in the ring, utilizing the four available Chandra observations totaling an effective exposure of 179 ks. We report photometric properties of these sources in a point-source catalog. There are approx. 40% of the bulge sources and approx. 25% of the ring sources showing > 3(sigma) long-term variability in their X-ray count rate. The X-ray colors suggest that a significant fraction of the bulge (approx. 75%) and ring (approx. 65%) sources are likely low-mass X-ray binaries (LMXBs). The spectra of the nuclear source indicate that it is a low-luminosity AGN with moderate obscuration; spectral variability is observed between individual observations. We construct 0.3-8.0 keV X-ray luminosity functions (XLFs) for the bulge and ring XRB populations, taking into account the detection incompleteness and background AGN contamination. We reach 90% completeness limits of approx.1.5 x 10(exp 37) and approx. 2.2 x 10(exp 37) erg/s for the bulge and ring populations, respectively. Both XLFs can be fit with a broken power-law model, and the shapes are consistent with those expected for populations dominated by LMXBs. We perform detailed population synthesis modeling of the XRB populations in NGC 1291 , which suggests that the observed combined XLF is dominated by aD old LMXB population. We compare the bulge and ring XRB populations, and argue that the ring XRBs are associated with a younger stellar population than the bulge sources, based on the relative over-density of X-ray sources in the ring, the generally harder X-ray color of the ring sources, the overabundance of luminous sources in the combined XLF, and the flatter shape of the ring XLF.

  12. Understanding Black Hole X-ray Binaries: The Case of Cygnus X-1

    NASA Technical Reports Server (NTRS)

    Pottschmidt, Katja

    2008-01-01

    Black Hole X-ray Binaries are known to display distinct emission states that differ in their X-ray spectra, their X-ray timing properties (on times scales less than 1 s) and their radio emission. In recent years monitoring observations, specially with NASA's Rossi X-ray Timing Explorer (RXTE), have provided us with detailed empirical modeling of the phenomenology of the different states as well as a unification scheme of the long term evolution of black holes, transient and persistent, in terms of these states. Observations of the persistent High Mass X-ray Binary (HMXB) Cygnus X-l have been at the forefront of learning about black hole states since its optical identification through a state transition in 1973. In this talk I will present in depth studies of several different aspects of the accretion process in this system. The main data base for these studies is an ongoing RXTE and Ryle radio telescope bi-weekly monitoring campaign that started in 1997. I will discuss high-resolution timing results, especially power spectra, which first gave rise to the Lorentzian description now widely used for black hole and neutron star binaries, and time lags, which we found to be especially well suited to identify state transitions. The evolution of spectral, timing, and radio parameters over years will be shown, including the rms-flux relation and the observation of a clearly correlated radio/x-ray flare. We also observed Cygnus X-1 with INTEGRAL, which allowed us to extend timing and spectral studies to higher energies, with XMM, which provided strong constraints on the parameters of the 6.4 keV iron fluorescence line, and with Chandra, which provided the most in depth study to date of the stellar wind in this system. Models based on the physical conditions in the accretion region are still mainly concentrated on the one or other of the observational areas but they are expanding: as an example I will review results from a jet model for the quantitative description of the

  13. Coordinated X-Ray, Ultraviolet, Optical, and Radio Observations of the PSR J1023+0038 System in a Low-mass X-Ray Binary State

    NASA Astrophysics Data System (ADS)

    Bogdanov, Slavko; Archibald, Anne M.; Bassa, Cees; Deller, Adam T.; Halpern, Jules P.; Heald, George; Hessels, Jason W. T.; Janssen, Gemma H.; Lyne, Andrew G.; Moldón, Javier; Paragi, Zsolt; Patruno, Alessandro; Perera, Benetge B. P.; Stappers, Ben W.; Tendulkar, Shriharsh P.; D'Angelo, Caroline R.; Wijnands, Rudy

    2015-06-01

    The PSR J1023+0038 binary system hosts a neutron star and a low-mass, main-sequence-like star. It switches on year timescales between states as an eclipsing radio millisecond pulsar and a low-mass X-ray binary (LMXB). We present a multi-wavelength observational campaign of PSR J1023+0038 in its most recent LMXB state. Two long XMM-Newton observations reveal that the system spends ˜70% of the time in a ≈3 × 1033 erg s-1 X-ray luminosity mode, which, as shown in Archibald et al., exhibits coherent X-ray pulsations. This emission is interspersed with frequent lower flux mode intervals with ≈ 5× {10}32 erg s-1 and sporadic flares reaching up to ≈1034 erg s-1, with neither mode showing significant X-ray pulsations. The switches between the three flux modes occur on timescales of order 10 s. In the UV and optical, we observe occasional intense flares coincident with those observed in X-rays. Our radio timing observations reveal no pulsations at the pulsar period during any of the three X-ray modes, presumably due to complete quenching of the radio emission mechanism by the accretion flow. Radio imaging detects highly variable, flat-spectrum continuum radiation from PSR J1023+0038, consistent with an origin in a weak jet-like outflow. Our concurrent X-ray and radio continuum data sets do not exhibit any correlated behavior. The observational evidence we present bears qualitative resemblance to the behavior predicted by some existing “propeller” and “trapped” disk accretion models although none can account for key aspects of the rich phenomenology of this system.

  14. HST UV observations of the accretion disk corona X-ray binary X1822-371

    NASA Technical Reports Server (NTRS)

    Puchnarewicz, E. M.; Mason, K. O.; Cordova, F. A.

    1995-01-01

    The Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) has provided the first ultraviolet orbital light curve of the low-mass X-ray binary X1822-371. The shape of the UV light curve changes with wavelength providing the first direct clues to the temperature of the various system components. The data support the idea that the system contains a thick, structured accretion disk.

  15. X-ray specular reflectivity study of a critical binary fluid mixture.

    PubMed

    Marschand, L W; Brown, M; Lurio, L B; Law, B M; Uran, S; Kuzmenko, I; Gog, T

    2005-07-01

    We have used direct inversion of x-ray reflectivity data to extract the liquid-vapor interface composition profile and the related critical scaling function of a binary mixture of dodecane and tetrabromoethane. The mixture was in the one-phase region above its critical point. The results indicate the formation of a monolayer of the lower surface tension component followed by an abrupt change to a mixed composition which gradually relaxes to the bulk composition deep within the fluid.

  16. Quasars in miniature: new insights into particle acceleration from X-ray binaries

    NASA Astrophysics Data System (ADS)

    Markoff, Sera

    2013-04-01

    A variety of astronomical objects routinely accelerate particles to high energy, with the maximum possible energy per particle typically limited by the size of the system and magnetic field strength. For that reason, much attention has focused on the massive jets of relativistic plasma ejected from supermassive black holes in Active Galactic Nuclei (AGN), which are at least theoretically capable of producing particles (cosmic rays) up to a whopping 10{20 }eV. However neither how these jets are formed or function, nor how exactly they accelerate particles, is well understood. While we do not expect the mechanisms for particle acceleration in stellar remnant black holes within X-ray binaries (XRBs) to be particularly different than in other sources, XRBs do offer some unique insights. Primarily, jets very similar to those in AGN come and go on timescales of weeks to months, while often monitored simultaneously across the entire electromagnetic spectrum. Through such observations we have been able to probe the processes by which jets not only build up dynamically, but also at what point the jets begin to accelerate particles, providing hints about the necessary conditions and efficiencies. Because the physics of accretion-driven processes such as jets seems to scale predictably with black hole mass, we can also potentially apply what we are learning in these smaller systems to the same phenomena AGN, giving us a new handle on several longstanding questions. I will review our current understanding of particle acceleration in XRBs, as well as the increasing body of evidence suggesting that XRBs indeed seem to represent scaled-down (and thus handily faster evolving) versions of the much more powerful AGN. I will also touch on how accelerated particles from XRBs may contribute significantly to the low-energy Galactic cosmic ray distribution, with local impact on gas chemistry and star formation.

  17. Evidence for a black hole in the X-ray binary Nova Muscae 1991

    NASA Technical Reports Server (NTRS)

    Remillard, Ronald A.; Mcclintock, Jeffrey E.; Bailyn, Charles D.

    1992-01-01

    Optical photometry and spectroscopy of the X-ray Nova Muscae 1991 in quiescence reveal an orbital period of 10.398 +/- 0.014 hr and an absorption-line velocity curve consistent with a sinusoidal modulation at a half-amplitude of 409 +/- 18 km/s. The spectral type of the secondary star is in the range K0 V to K4 V. The value of the mass function, 3.1 +/- 0.4 solar mass, is a conservative lower limit on the mass of the compact primary and suggests that the primary is a black hole. Further considerations of the binary inclination angle and the mass of the secondary strengthen the black hole model. The folded light curves in the I band and the B + V band resemble ellipsoidal variations, with an additional brightening near one of the maxima in the B + V band. The orbital period is 1.4 percent shorter than the photometric period observed during outburst, as expected if the outburst modulations are analogs of 'superhumps' in dwarf novae. In quiescence, the optical properties of the X-ray binary Nova Muscae 1991 bear a striking resemblance to the black hole binary A0620-00, which extends the basis of similarity that was demonstrated during outburst at X-ray and optical wavelengths.

  18. Energy dependent variability and outburst evolution in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Stiele, H.; Kong, A. K. H.

    2016-12-01

    Almost all low mass black hole X-ray binaries are transient sources. Most of these sources show a certain pattern during outburst: the evolution from low hard state through intermediate state(s) into high soft state and the returning to the hard state at lower luminosity. However, there are outbursts that remain in the hard state (so called "failed" outbursts). Using the technique of covariance spectra we can investigate the variability of individual spectral components on different time scales. Comprehensive studies of covariance spectra for a sample of black hole X-ray binaries observed in the rising low hard state of "normal" outbursts revealed an increase of the covariance ratios towards lower energies that has been interpreted as the sign of additional disc variability on long time scales. There are now two sources (h1743 and gs) that do not show an increase towards lower energies in their covariance ratio. Both sources have been observed during "failed" outbursts and showed photon indices much harder than what is usually observed in black hole X-ray binaries.

  19. On binary-driven hypernovae and their nested late X-ray emission

    NASA Astrophysics Data System (ADS)

    Ruffini, R.; Muccino, M.; Bianco, C. L.; Enderli, M.; Izzo, L.; Kovacevic, M.; Penacchioni, A. V.; Pisani, G. B.; Rueda, J. A.; Wang, Y.

    2014-05-01

    Context. The induced gravitational collapse (IGC) paradigm addresses the very energetic (1052-1054 erg) long gamma-ray bursts (GRBs) associated to supernovae (SNe). Unlike the traditional "collapsar" model, an evolved FeCO core with a companion neutron star (NS) in a tight binary system is considered as the progenitor. This special class of sources, here named "binary-driven hypernovae" (BdHNe), presents a composite sequence composed of four different episodes with precise spectral and luminosity features. Aims: We first compare and contrast the steep decay, the plateau, and the power-law decay of the X-ray luminosities of three selected BdHNe (GRB 060729, GRB 061121, and GRB 130427A). Second, to explain the different sizes and Lorentz factors of the emitting regions of the four episodes, for definiteness, we use the most complete set of data of GRB 090618. Finally, we show the possible role of r-process, which originates in the binary system of the progenitor. Methods: We compare and contrast the late X-ray luminosity of the above three BdHNe. We examine correlations between the time at the starting point of the constant late power-law decay t*a, the average prompt luminosity ⟨ Liso ⟩, and the luminosity at the end of the plateau La. We analyze a thermal emission (~ 0.97-0.29 keV), observed during the X-ray steep decay phase of GRB 090618. Results: The late X-ray luminosities of the three BdHNe, in the rest-frame energy band 0.3-10 keV, show a precisely constrained "nested" structure. In a space-time diagram, we illustrate the different sizes and Lorentz factors of the emitting regions of the three episodes. For GRB 090618, we infer an initial dimension of the thermal emitter of ~ 7 × 1012 cm, expanding at Γ ≈ 2. We find tighter correlations than the Dainotti-Willingale ones. Conclusions: We confirm a constant slope power-law behavior for the late X-ray luminosity in the source rest frame, which may lead to a new distance indicator for BdHNe. These results

  20. The Galactic Population of Low- and Intermediate-Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Pfahl, Eric; Rappaport, Saul; Podsiadlowski, Philipp

    2003-11-01

    We present the first study that combines binary population synthesis in the Galactic disk and detailed evolutionary calculations of low- and intermediate-mass X-ray binaries (L/IMXBs). Our approach allows us to follow completely the formation of incipient L/IMXBs and their evolution through the mass-transfer phase to the point when they become binary millisecond pulsars (BMPs). We show that the formation probability of IMXBs with initial donor masses of 1.5-4Msolar is typically >~5 times higher than that of standard LMXBs with initial donor masses of less than 1.5Msolar. Since IMXBs evolve to resemble observed LMXBs, we suggest that the majority of the observed systems may have descended from IMXBs. Distributions at the current epoch of the orbital periods, donor masses, and mass accretion rates of L/IMXBs have been computed, as have orbital-period distributions of BMPs. This is a major step forward over previous theoretical population studies of L/IMXBs that utilized only crude representations of the binary evolution through the X-ray phase. Several significant discrepancies between the theoretical and observed distributions are discussed. We find that the total number of luminous (LX>1036ergss-1) X-ray sources at the current epoch and the period distribution of BMPs are very sensitive to the parameters in the analytic formula describing the common-envelope phase that precedes the formation of the neutron star. The orbital-period distribution of observed BMPs strongly favors cases in which the common envelope is more easily ejected. However, this leads to an approximately hundred-fold overproduction of the theoretical number of luminous X-ray sources relative to the total observed number of LMXBs. As noted by several groups prior to our study, X-ray irradiation of the donor star may result in a dramatic reduction in the X-ray active lifetime of L/IMXBs, and we suggest that irradiation may resolve the overproduction problem as well as the long-standing BMP

  1. Faint X-ray binaries and their optical counterparts in M31

    SciTech Connect

    Vulic, N.; Gallagher, S. C.; Barmby, P.

    2014-08-01

    X-ray binaries (XRBs) are probes of both star formation and stellar mass, but more importantly remain one of the only direct tracers of the compact object population. To investigate the XRB population in M31, we utilized all 121 publicly available observations of M31 totalling over 1 Ms from Chandra's ACIS instrument. We studied 83 star clusters in the bulge using the year 1 star cluster catalogue from the Panchromatic Hubble Andromeda Treasury Survey. We found 15 unique star clusters that matched to 17 X-ray point sources within 1'' (3.8 pc). This population is composed predominantly of globular cluster low-mass XRBs, with one previously unidentified star cluster X-ray source. Star clusters that were brighter and more compact preferentially hosted an X-ray source. Specifically, logistic regression showed that the F475W magnitude was the most important predictor followed by the effective radius, while color (F475W–F814W) was not statistically significant. We also completed a matching analysis of 1566 H II regions and found 10 unique matches to 9 X-ray point sources within 3'' (11 pc). The H II regions hosting X-ray point sources were on average more compact than unmatched H II regions, but logistic regression concluded that neither the radius nor Hα luminosity was a significant predictor. Four matches have no previous classification and thus are high-mass XRB candidates. A stacking analysis of both star clusters and H II regions resulted in non-detections, giving typical upper limits of ≈10{sup 32} erg s{sup –1}, which probes the quiescent XRB regime.

  2. DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY

    SciTech Connect

    Seward, F. D.; Charles, P. A.; Foster, D. L.; Dickel, J. R.; Romero, P. S.; Edwards, Z. I.; Perry, M.; Williams, R. M.

    2012-11-10

    A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M {sub Sun}.

  3. Steady-State Models of X-ray Emission from Massive-Star Magnetospheres

    NASA Astrophysics Data System (ADS)

    Bard, Christopher; Townsend, Richard D.

    2016-01-01

    In the subset of OB stars with large-scale, organized magnetic fields, the stellar wind is forced to flow along magnetic field lines and is trapped within a magnetosphere corotating with its host star. As the wind turns on itself, shocks heat the plasma to millions of degrees and produce X-ray emission. Such magnetospheres are typically classified with the "wind magnetic confinement parameter", a simplified ratio between the magnetic energy density and the wind kinetic energy density. This parameter is often used to estimate magnetosphere properties, such as size, mass-loss rate, and spin-down time. Unfortunately, the strong magnetic fields in magnetospheres (polar strength: 100 G - 10 kG) and resulting Alfven velocities make magnetohydrodynamics simulations computationally difficult due to very small timesteps. To get around this issue, we approximate a massive-star magnetosphere as a series of one-dimensional flows along magnetic dipole field lines and develop a steady-state model from the resulting hydrodynamic equations. With this model, we derive scaling relations for the stellar mass-loss rate as a function of surface colatitude and find agreement with previous scaling results derived from simulations. These relations are further extended to include the effects of rigid-body rotation within the magnetosphere. Additionally, we develop an X-ray emission model from this steady-state analysis and compare it against both the "XADM" model for X-ray emission from massive star magnetospheres and observations of massive magnetic stars. Finally, we discuss improvements to the traditional wind magnetic confinement parameter to take into account the effect of a magnetic field on the wind kinetic energy density.

  4. X-ray and γ-ray studies of the millisecond pulsar and possible X-ray binary/radio pulsar transition object PSR J1723-2837

    SciTech Connect

    Bogdanov, Slavko; Esposito, Paolo; Crawford III, Fronefield; Possenti, Andrea; McLaughlin, Maura A.; Freire, Paulo

    2014-01-20

    We present X-ray observations of the 'redback' eclipsing radio millisecond pulsar (MSP) and candidate radio pulsar/X-ray binary transition object PSR J1723-2837. The X-ray emission from the system is predominantly non-thermal and exhibits pronounced variability as a function of orbital phase, with a factor of ∼2 reduction in brightness around superior conjunction. Such temporal behavior appears to be a defining characteristic of this variety of peculiar MSP binaries and is likely caused by a partial geometric occultation by the main-sequence-like companion of a shock within the binary. There is no indication of diffuse X-ray emission from a bow shock or pulsar wind nebula associated with the pulsar. We also report on a search for point source emission and γ-ray pulsations in Fermi Large Area Telescope data using a likelihood analysis and photon probability weighting. Although PSR J1723-2837 is consistent with being a γ-ray point source, due to the strong Galactic diffuse emission at its position a definitive association cannot be established. No statistically significant pulsations or modulation at the orbital period are detected. For a presumed detection, the implied γ-ray luminosity is ≲5% of its spin-down power. This indicates that PSR J1723-2837 is either one of the least efficient γ-ray producing MSPs or, if the detection is spurious, the γ-ray emission pattern is not directed toward us.

  5. Revealing Massive Black Holes in Dwarf Galaxies with X-rays

    NASA Astrophysics Data System (ADS)

    Reines, A.

    2014-07-01

    Supermassive black holes (BHs) live at the heart of essentially all massive galaxies, power AGN, and are thought to be important agents in the evolution of their hosts. However, the origin of these monster BHs is largely unknown. While direct observations of the first ``seeds" of supermassive BHs in the infant Universe are unobtainable with current telescopes, finding and studying dwarf galaxies hosting massive BHs today can provide valuable constraints on the masses, host galaxies, and formation mechanism of supermassive BH seeds. We have recently completed the first systematic search for AGN in dwarf galaxies using optical spectroscopy, increasing the number of known dwarfs with massive BHs by more than an order of magnitude (Reines et al. 2013). However, this optical search is biased towards BHs radiating at high fractions of their Eddington limit in galaxies with little on-going star formation. Alternative search techniques and diagnostics at other wavelengths are necessary to make further progress. I will discuss our efforts to find and study massive BHs in dwarf galaxies using observations at X-ray wavelengths. These observations are more sensitive to weakly accreting massive BHs and are already beginning to reveal massive BHs hidden at optical wavelengths in star-forming dwarf galaxies.

  6. The Reverberation Lag in the Low-mass X-ray Binary H1743-322

    NASA Astrophysics Data System (ADS)

    De Marco, Barbara; Ponti, Gabriele

    2016-07-01

    The evolution of the inner accretion flow of a black hole X-ray binary during an outburst is still a matter of active research. X-ray reverberation lags are powerful tools for constraining disk-corona geometry. We present a study of X-ray lags in the black hole transient H1743-322. We compared the results obtained from analysis of all the publicly available XMM-Newton observations. These observations were carried out during two different outbursts that occurred in 2008 and 2014. During all the observations the source was caught in the hard state and at similar luminosities ({L}3-10{keV}/{L}{Edd}˜ 0.004). We detected a soft X-ray lag of ˜60 ms, most likely due to thermal reverberation. We did not detect any significant change of the lag amplitude among the different observations, indicating a similar disk-corona geometry at the same luminosity in the hard state. On the other hand, we observe significant differences between the reverberation lag detected in H1743-322 and in GX 339-4 (at similar luminosities in the hard state), which might indicate variations of the geometry from source to source.

  7. Isotropic Detectable X-Ray Counterparts to Gravitational Waves from Neutron Star Binary Mergers

    NASA Astrophysics Data System (ADS)

    Kisaka, Shota; Ioka, Kunihito; Nakamura, Takashi

    2015-08-01

    Neutron star binary mergers are strong sources of gravitational waves (GWs). Promising electromagnetic counterparts are short gamma-ray bursts (GRBs), but the emission is highly collimated. We propose that the scattering of the long-lasting plateau emission in short GRBs by the merger ejecta produces nearly isotropic emission for ˜ {10}4 s with flux {10}-13-{10}-10 erg cm-2 s-1 at 100 Mpc in X-ray. This is detectable by Swift/XRT and wide field X-ray detectors such as ISS-Lobster, Einstein Probe, eROSITA, and WF-MAXI, which are desired by the infrared and optical follow-ups to localize and measure the distance to the host galaxy. The scattered X-rays obtain linear polarization, which correlates with the jet direction, X-ray luminosity, and GW polarizations. The activity of the plateau emission is also a natural energy source of a macronova (or kilonova) detected in short GRB 130603B without the r-process radioactivity.

  8. Wind-jet interaction in high-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Zdziarski, Andrzej

    2016-07-01

    Jets in high-mass X-ray binaries can strongly interact with the stellar wind from the donor. The interaction leads, in particular, to formation of recollimation shocks. The shocks can then accelerate electrons in the jet and lead to enhanced emission, observable in the radio and gamma-ray bands. DooSoo, Zdziarski & Heinz (2016) have formulated a condition on the maximum jet power (as a function of the jet velocity and wind rate and velocity) at which such shocks form. This criterion can explain the large difference in the radio and gamma-ray loudness between Cyg X-1 and Cyg X-3. The orbital modulation of radio emission observed in Cyg X-1 and Cyg X-3 allows a measurement of the location of the height along the jet where the bulk of emission at a given frequency occurs. Strong absorption of X-rays in the wind of Cyg X-3 is required to account for properties of the correlation of the radio emission with soft and hard X-rays. That absorption can also account for the unusual spectral and timing X-ray properties of this source.

  9. Classification of compact binaries: an X-ray analog to the HR diagram

    NASA Astrophysics Data System (ADS)

    Dil Vrtilek, Saeqa; Raymond, John C.; Gopalan, Giri; Boroson, Bram Seth; Bornn, Luke

    2016-06-01

    X-ray binary systems (XRBs), when examined in an appropriate coordinate system derived from X-ray spectral and intensity information, appear to cluster based on their compact object type. We introduce such a coordinate system, in which two coordinates are hardness ratios and the third is a broadband X-ray intensity. In Gopalan, Vrtilek, & Bornn (2015) we developed a Bayesian statistical model that estimates the probability that an XRB contains a black hole, non-pulsing neutron star, or pulsing neutron star, depending on its location in our coordinate space. In particular, we utilized a latent variable model in which the latent variables follow a Gaussian process prior distribution. Here we expand our work to incorporate systems where the compact object is a white dwarf: cataclysmic variables (CVs). The fact that the CVs also fall into a location spatially distinct from the other XRB types supports the use of X-ray color-color-intensity diagrams as 3-dimensional analogs to the Hertzsprung-Russell diagram for normal stars.

  10. Chandra Observations of the Faintest Low-Mass X-ray Binaries

    NASA Technical Reports Server (NTRS)

    Wilson, Colleen A.; Patel, Sandeep K.; Kouveliotou, Chryssa; Jonker, Peter G.; vanderKlis, Michiel; Lewin, Walter H. G.; Belloni, Tomaso

    2003-01-01

    There exists a group of persistently faint galactic X-ray sources that, based on their location in the galaxy, high L(sub X)/L(sub opt), association with X-ray bursts, and absence of low frequency X-ray pulsations, are thought to be low-mass X-ray binaries (LMXBs). We present results from Chandra observations for 8 of these systems: 4U 1708-408, 2S 1711-339, KS 1739-304, SLX 1735-269, GRS 1736-297, SLX 1746-331, 1E 1746.7-3224, and 4U 1812-12. Locations for all sources, excluding GRS 1736-297, SLX 1746-331, and KS 1739-304 (which were not detected) were improved to 0.6 sec error circles (90% confidence). Our observations support earlier findings of transient behavior of GRS 1736-297, KS 1739-304, SLX 1746-331, and 2S 1711-339 (which we detect in one of two observations). Energy spectra for 4U 1708-408,2S 1711-339, SLX 1735-269, 1E 1746.7-3224, and 4U 1812-12 are hard, with power law indices typically 1.4-2.1, which are consistent with typical faint LMXB spectra.

  11. Chandra Observations of the Faintest Low-Mass X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Wilson, Colleen A.; Patel, Sandeep K.; Kouveliotou, Chryssa; Jonker, Peter G.; vanderKlis, Michiel; Lewin, Walter H. G.; Belloni, Tomaso; Mendez, Mariano

    2003-01-01

    A group of persistently faint Galactic X-ray sources exist that, based on their location in the Galaxy, high L(sub X)/L(sub opt), association with X-ray bursts, and absence of low-frequency X-ray pulsations, are thought to be low-mass X-ray binaries (LMXBs). We present results from Chandra observations for eight of these systems: 4U 1708-408, 2S 1711-339, KS 1739-304, SLX 1735-269, GRS 1736-297, SLX 1746-331, 1E 1746.7-3224, and 4U 1812-12. Locations for all these sources, excluding GRS 1736-297, SLX 1746-331, and KS 1739-304 (which were not detected), were improved to 0.6 sec error circles (90% confidence). Our observations support earlier findings of transient behavior of GRS 1736-297, KS 1739-304, SLX 1746-331, and 2S 1711-339 (which we detect in one of two observations). Energy spectra for 4U 1708-408, 2S 1711-339, SLX 1735-269, 1E 1746.7-3224, and 4U 1812-12 are hard, with power-law indices typically 1.4-2.1, which is consistent with typical faint LMXB spectra.

  12. Detection of the Second Eclipsing High-Mass X-Ray Binary in M 33

    NASA Astrophysics Data System (ADS)

    Pietsch, Wolfgang; Haberl, Frank; Gaetz, Terrance J.; Hartman, Joel D.; Plucinsky, Paul P.; Tüllmann, Ralph; Williams, Benjamin F.; Shporer, Avi; Mazeh, Tsevi; Pannuti, Thomas G.

    2009-03-01

    Chandra data of the X-ray source [PMH2004] 47 were obtained in the ACIS Survey of M 33 (ChASeM33) in 2006. During one of the observations, the source varied from a high state to a low state and back, in two other observations it varied from a low state to respectively intermediate states. These transitions are interpreted as eclipse ingresses and egresses of a compact object in a high-mass X-ray binary (HMXB) system. The phase of mideclipse is given by HJD 245 3997.476 ± 0.006, the eclipse half angle is 30fdg6 ± 1fdg2. Adding XMM-Newton observations of [PMH2004] 47 in 2001 we determine the binary period to be 1.732479 ± 0.000027 days. This period is also consistent with ROSAT HRI observations of the source in 1994. No short-term periodicity compatible with a rotation period of the compact object is detected. There are indications for a long-term variability similar to that detected for Her X-1. During the high state the spectrum of the source is hard (power-law spectrum with photon index ~0.85) with an unabsorbed luminosity of 2 ×1037 erg s-1 (0.2-4.5 keV). We identify as an optical counterpart a V ~ 21.0 mag star with T eff>19000 K, log(g)>2.5. The Canada-France-Hawaii Telescope optical light curves for this star show an ellipsoidal variation with the same period as the X-ray light curve. The optical light curve together with the X-ray eclipse can be modeled by a compact object with a mass consistent with a neutron star or a black hole in an HMXB. However, the hard power-law X-ray spectrum favors a neutron star as the compact object in this second eclipsing X-ray binary in M 33. Assuming a neutron star with a canonical mass of 1.4 M sun and the best-fit companion temperature of 33,000 K, a system inclination i = 72° and a companion mass of 10.9 M sun are implied.

  13. THE QUIESCENT X-RAY PROPERTIES OF THE ACCRETING MILLISECOND X-RAY PULSAR AND ECLIPSING BINARY SWIFT J1749.4-2807

    SciTech Connect

    Degenaar, N.; Patruno, A.; Wijnands, R.

    2012-09-10

    Swift J1749.4-2807 is a transient neutron star low-mass X-ray binary that contains an accreting millisecond X-ray pulsar spinning at 518 Hz. It is the first of its kind that displays X-ray eclipses, which holds significant promise to precisely constrain the mass of the neutron star. We report on a {approx_equal} 105 ks long XMM-Newton observation performed when Swift J1749.4-2807 was in quiescence. We detect the source at a 0.5-10 keV luminosity of {approx_equal}1 Multiplication-Sign 10{sup 33}(D/6.7 kpc){sup 2} erg s{sup -1}. The X-ray light curve displays three eclipses that are consistent in orbital phase and duration with the ephemeris derived during outburst. Unlike most quiescent neutron stars, the X-ray spectrum can be adequately described with a simple power law, while a pure-hydrogen atmosphere model does not fit the data. We place an upper limit on the 0.01-100 keV thermal luminosity of the cooling neutron star of {approx}< 2 Multiplication-Sign 10{sup 33} erg s{sup -1} and constrain its temperature to be {approx}< 0.1 keV (for an observer at infinity). Timing analysis does not reveal evidence for X-ray pulsations near the known spin frequency of the neutron star or its first overtone with a fractional rms of {approx}< 34% and {approx}< 28%, respectively. We discuss the implications of our findings for dynamical mass measurements, the thermal state of the neutron star, and the origin of the quiescent X-ray emission.

  14. Unification of Low Luminosity AGN and Hard State X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Connolly, S.

    2015-09-01

    We present X-ray spectral variability of four low accretion rate and low luminosity AGN (LLAGN)- M81, NGC 1097, NGC 1052 and NGC 3998 - as observed by Swift and RXTE. All four objects were selected due to having spectra which hardened with increasing count rate, converse to the 'softer when brighter' behaviour normally observed in AGN with higher accretion rates. The spectra were summed in flux bins and fitted with a variety of models. A simple absorbed power law model was found to fit the spectra of M81, NGC 1097 and NGC 3998 well, whilst NGC 1052 required a partially covered power law model. In all four cases, the most likely cause of spectral variability is found to be hardening of the photon index of the power law component with increasing luminosity. Such a correlation has been seen previously within samples of low accretion rate AGN but in only one case has it been seen within observations of a single AGN. Here we show that such behaviour may be very common in LLAGN. A similar anticorrelation is found in X-ray binary systems in the 'hard state', at low accretion rates similar to those of the LLAGN discussed here. Our observations thus imply that LLAGN are the active galaxy equivalent of hard state X-ray binaries.

  15. Polarization Radiation with Turbulent Magnetic Fields from X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Zhang, Jian-Fu; Xiang, Fu-Yuan; Lu, Ju-Fu

    2017-02-01

    We study the properties of polarized radiation in turbulent magnetic fields from X-ray binary jets. These turbulent magnetic fields are composed of large- and small-scale configurations, which result in the polarized jitter radiation when the characteristic length of turbulence is less than the non-relativistic Larmor radius. On the contrary, the polarized synchrotron emission occurs, corresponding to a large-scale turbulent environment. We calculate the spectral energy distributions and the degree of polarization for a general microquasar. Numerical results show that turbulent magnetic field configurations can indeed provide a high degree of polarization, which does not mean that a uniform, large-scale magnetic field structure exists. The model is applied to investigate the properties of polarized radiation of the black-hole X-ray binary Cygnus X-1. Under the constraint of multiband observations of this source, our studies demonstrate that the model can explain the high polarization degree at the MeV tail and predict the highly polarized properties at the high-energy γ-ray region, and that the dominant small-scale turbulent magnetic field plays an important role for explaining the highly polarized observation at hard X-ray/soft γ-ray bands. This model can be tested by polarization observations of upcoming polarimeters at high-energy γ-ray bands.

  16. Spectral-Timing to Probe Strong Gravity in X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Stevens, Abigail; Uttley, Phil

    2017-01-01

    X-ray spectral-timing seeks to investigate how matter behaves in strong gravitational fields. Observations suggest that different types of quasi-periodic oscillations (QPOs) are associated with different emission-region geometries (e.g. disk-like or jet-like) in the innermost part of an X-ray binary, close to the neutron star or black hole. We developed a technique for phase-resolved spectroscopy of QPOs, and have applied it to low-frequency QPOs from black hole X-ray binaries. On the QPO time-scale, we find that the energy spectrum changes not only in normalization, but also in spectral shape. We identify these changes as a phase-dependence of the intrinsic power-law emission as well as the response of the accretion disk to variable illumination by the power-law. We also look for systematic trends between different classes of sources and different accretion states. These trends help us to further constrain the origin of low-frequency QPOs and QPO evolution with the changing emission geometry in the strong-gravity regime.

  17. POTENTIAL GAMMA-RAY EMISSIONS FROM LOW-MASS X-RAY BINARY JETS

    SciTech Connect

    Zhang, Jian-Fu; Gu, Wei-Min; Liu, Tong; Xue, Li; Lu, Ju-Fu E-mail: guwm@xmu.edu.cn

    2015-06-20

    By proposing a pure leptonic radiation model, we study the potential gamma-ray emissions from the jets of low-mass X-ray binaries. In this model, the relativistic electrons that are accelerated in the jets are responsible for radiative outputs. Nevertheless, jet dynamics are dominated by magnetic and proton–matter kinetic energies. The model involves all kinds of related radiative processes and considers the evolution of relativistic electrons along the jet by numerically solving the kinetic equation. Numerical results show that the spectral energy distributions can extend up to TeV bands, in which synchrotron radiation and synchrotron self-Compton scattering are dominant components. As an example, we apply the model to the low-mass X-ray binary GX 339–4. The results not only can reproduce the currently available observations from GX 339–4, but also predict detectable radiation at GeV and TeV bands by the Fermi and CTA telescopes. Future observations with Fermi and CTA can be used to test our model, which could be employed to distinguish the origin of X-ray emissions.

  18. X-Ray Emission from an Asymmetric Blast Wave and a Massive White Dwarf in the Gamma Ray Emitting Nova V407 CYG

    NASA Technical Reports Server (NTRS)

    Nelson, Thomas; Donato, Davide; Mukai, Koji; Sokoloski, Jennifer; Chomiuk, Laura

    2012-01-01

    Classical nova events in symbiotic stars, although rare, offer a unique opportunity to probe the interaction between ejecta and a dense environment in stellar explosions. In this work, we use X-ray data obtained with Swift and Suzaku during the recent classical nova outburst in V407 Cyg to explore such an interaction. We find evidence of both equilibrium and non-equilibrium ionization plasmas at the time of peak X-ray brightness, indicating a strong asymmetry in the density of the emitting region. Comparing a simple model to the data, we find that the X-ray evolution is broadly consistent with nova ejecta driving a forward shock into the dense wind of the Mira companion. We detect a highly absorbed soft X-ray component in the spectrum during the first 50 days of the outburst that is consistent with supersoft emission from the nuclear burning white dwarf. The high temperature and short turn off time of this emission component, in addition to the observed breaks in the optical and UV lightcurves, indicate that the white dwarf in the binary is extremely massive. Finally, we explore the connections between the X-ray and GeV-ray evolution, and propose that the gamma ray turn-off is due to the stalling of the forward shock as the ejecta reach the red giant surface.

  19. The coupling of a disk corona and a jet for the radio/X-ray correlation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Qiao, Erlin

    2016-02-01

    We interpret the radio/X-ray correlation of L R ~ L X ~1.4 for L X/L Edd >~ 10-3 with a detailed disk corona-jet model, in which the accretion flow and the jet are connected by a parameter, η, describing the fraction of the matter in the accretion flow ejected outward to form the jet. We calculate L R and L X at different Ṁ, adjusting η to fit the observed radio/X-ray correlation of the black hole X-ray transient H1743-322 for L X/L Edd > 10-3. It is found that the value of η for this radio/X-ray correlation for L X/L Edd > 10-3, is systematically less than that of the case for L X/L Edd < 10-3, which is consistent with the general idea that the jet is often relatively suppressed at the high luminosity phase in black hole X-ray binaries.

  20. ECLIPSE TIMINGS OF THE TRANSIENT LOW-MASS X-RAY BINARY EXO 0748-676. IV. THE ROSSI X-RAY TIMING EXPLORER ECLIPSES

    SciTech Connect

    Wolff, Michael T.; Ray, Paul S.; Wood, Kent S.; Hertz, Paul L. E-mail: Paul.Ray@nrl.navy.mil E-mail: Paul.Hertz@nasa.gov

    2009-07-01

    We report our complete database of X-ray eclipse timings of the low-mass X-ray binary EXO 0748-676 observed by the Rossi X-Ray Timing Explorer (RXTE) satellite. As of this writing we have accumulated 443 full X-ray eclipses, 392 of which have been observed with the Proportional Counter Array on RXTE. These include both observations where an eclipse was specifically targeted and those eclipses found in the RXTE data archive. Eclipse cycle count has been maintained since the discovery of the EXO 0748-676 system in 1985 February. We describe our observing and analysis techniques for each eclipse and describe improvements we have made since the last compilation by Wolff et al. The principal result of this paper is the database containing the timing results from a seven-parameter fit to the X-ray light curve for each observed eclipse along with the associated errors in the fitted parameters. Based on the standard O - C analysis, EXO 0748-676 has undergone four distinct orbital period epochs since its discovery. In addition, EXO 0748-676 shows small-scale events in the O - C curve that are likely due to short-lived changes in the secondary star.

  1. X-RAY EMISSION FROM THE BINARY CENTRAL STARS OF THE PLANETARY NEBULAE HFG 1, DS 1, AND LOTR 5

    SciTech Connect

    Montez, Rodolfo; Kastner, Joel H.; De Marco, Orsola; Chu, You-Hua

    2010-10-01

    Close binary systems undergoing mass transfer or common envelope interactions can account for the morphological properties of some planetary nebulae. The search for close binary companions in planetary nebulae is hindered by the difficulty of detecting cool, late-type, main-sequence companions in binary systems with hot pre-white-dwarf primaries. However, models of binary planetary nebula progenitor systems predict that mass accretion or tidal interactions can induce rapid rotation in the companion, leading to X-ray-emitting coronae. To test such models, we have searched for, and detected, X-ray emission from three binary central stars within planetary nebulae: the post-common envelope close binaries in HFG 1 and DS 1 consisting of O-type subdwarfs with late-type, main-sequence companions and the binary system in LoTr 5 consisting of O-type subdwarf and rapidly rotating, late-type giant companion. The X-ray emission in each case is best characterized by spectral models consisting of two optically thin thermal plasma components with characteristic temperatures of {approx}10 MK and 15-40 MK and total X-ray luminosities {approx}10{sup 30} erg s{sup -1}. We consider the possible origin of the X-ray emission from these binary systems and conclude that the most likely origin is, in each case, a corona around the late-type companion, as predicted by models of interacting binaries.

  2. X-ray accretion signatures in the close CTTS binary V4046 Sagittarii

    NASA Astrophysics Data System (ADS)

    Günther, H. M.; Liefke, C.; Schmitt, J. H. M. M.; Robrade, J.; Ness, J.-U.

    2006-11-01

    We present Chandra HETGS observations of the classical T Tauri star (CTTS) V4046 Sgr. The He-like triplets of O VII, Ni IX, and Si XIII are clearly detected. Similar to the CTTS TW Hya and BP Tau, the forbidden lines of O VII and Ne IX are weak compared to the intercombination line, indicating high plasma densities in the X-ray emitting regions. The Si XIII triplet, however, is within the low-density limit, in agreement with the predictions of the accretion funnel infall model with an additional stellar corona. V4046 Sgr is the first close binary exhibiting these features. Together with previous high-resolution X-ray data on TW Hya and BP Tau, and in contrast to T Tau, now three out of four CTTS show evidence of accretion funnels.

  3. V404 Cyg - an Interacting Black-Hole Low-Mass X-ray Binary

    NASA Astrophysics Data System (ADS)

    Fox, Ori; Mauerhan, Jon; Graham, Melissa

    2015-07-01

    This DDT proposal is prompted by the June 15, 2015 outburst of V404 Cyg, a black-hole (BH) low-mass X-ray binary (LMXB). This outburst stands out since it is the first black hole system with a measured parallax, lying at a distance of only 2.39+/-0.14 kpc. An extensive and loosely organized multi-wavelength campaign is already underway by the astronomical community. One of the missing pieces of the puzzle is the mid-infrared (IR). Combined with radio, optical, and X-ray data, the mid-IR will help to discriminate discriminate between an accretion disk, jet emission, or circumstellar dust scenarios. Spitzer offers a unique opportunity to observe at these wavelengths. Here we propose 4 very short (5-minutes at 3.6 and 4.5 micron) observations of IRAC hotometry to search for the presence of warm dust and, if present, constrain the heating mechanism.

  4. Near-infrared spectroscopy of the brightest neutron-star X-ray binaries

    NASA Astrophysics Data System (ADS)

    Homan, Jeroen; van den Berg, Maureen

    2014-02-01

    The bright persistent neutron-star X-ray binaries (NSXBs) show a wide variety of phenomena in X-rays that are thought to be driven by near-Eddington mass accretion rates. We have recently started a program of near-infrared photometric and spectroscopic observations of these sources with the aim to understand a broad range of properties of these systems; disk line emission, donor spectral type, and the relation between jet outflows and disk winds. Here we request Flamingos-2 spectra of two sources from different NSXB subclasses, GX 3+1 and GX 340+0, which are thought to accrete at stubstantially different rates. Our main goal is to acquire more information on how the above properties are related to each other and to mass accretion rate. We request a total of 5.1 hr.

  5. Monitoring the latest stages of a transient neutron star X-ray binary

    NASA Astrophysics Data System (ADS)

    Campana, Sergio

    2012-10-01

    Neutron star transient low mass X-ray binaries (TLMXB) are among the brightest sources in the X-ray sky. Their outbursts are well known and studied. Despite this, their return to quiescence has been studied only in a handful of cases. This return is quite fast making even more difficult. Recently we monitor in high detail the return to quiescence of the archetypal TLMXB Aql X-1 thanks to XMM-Newton observations. We probed for the first time the cooling of the neutron star after a (short) outburst, finding a very short cooling time ( 3d). Thanks to an approved Swift XRT program for monitoring every day for 5 ks (for 30 d) the latest stages of a TLMXB, we are aiming assessing the spectral properties of a transient LMXB close to the quiescent level.

  6. A transient supergiant X-ray binary in IC 10: An extragalactic SFXT?

    SciTech Connect

    Laycock, Silas; Cappallo, Rigel; Oram, Kathleen; Balchunas, Andrew

    2014-07-01

    We report the discovery of a large amplitude (factor of ∼100) X-ray transient (IC 10 X-2, CXOU J002020.99+591758.6) in the nearby dwarf starburst galaxy IC 10 during our Chandra monitoring project. Based on the X-ray timing and spectral properties, and an optical counterpart observed with Gemini, the system is a high-mass X-ray binary consisting of a luminous blue supergiant and a neutron star. The highest measured luminosity of the source was 1.8 × 10{sup 37} erg s{sup –1}during an outburst in 2003. Observations before, during, and after a second outburst in 2010 constrain the outburst duration to be less than 3 months (with no lower limit). The X-ray spectrum is a hard power law (Γ = 0.3) with fitted column density (N{sub H} = 6.3 × 10{sup 21} atom cm{sup –2}), consistent with the established absorption to sources in IC 10. The optical spectrum shows hydrogen Balmer lines strongly in emission at the correct blueshift (-340 km s{sup –1}) for IC 10. The N III triplet emission feature is seen, accompanied by He II [4686] weakly in emission. Together these features classify the star as a luminous blue supergiant of the OBN subclass, characterized by enhanced nitrogen abundance. Emission lines of He I are seen, at similar strength to Hβ. A complex of Fe II permitted and forbidden emission lines are seen, as in B[e] stars. The system closely resembles galactic supergiant fast X-ray transients, in terms of its hard spectrum, variability amplitude, and blue supergiant primary.

  7. WATCHDOG: A COMPREHENSIVE ALL-SKY DATABASE OF GALACTIC BLACK HOLE X-RAY BINARIES

    SciTech Connect

    Tetarenko, B. E.; Sivakoff, G. R.; Heinke, C. O.; Gladstone, J. C.

    2016-02-15

    With the advent of more sensitive all-sky instruments, the transient universe is being probed in greater depth than ever before. Taking advantage of available resources, we have established a comprehensive database of black hole (and black hole candidate) X-ray binary (BHXB) activity between 1996 and 2015 as revealed by all-sky instruments, scanning surveys, and select narrow-field X-ray instruments on board the INTErnational Gamma-Ray Astrophysics Laboratory, Monitor of All-Sky X-ray Image, Rossi X-ray Timing Explorer, and Swift telescopes; the Whole-sky Alberta Time-resolved Comprehensive black-Hole Database Of the Galaxy or WATCHDOG. Over the past two decades, we have detected 132 transient outbursts, tracked and classified behavior occurring in 47 transient and 10 persistently accreting BHs, and performed a statistical study on a number of outburst properties across the Galactic population. We find that outbursts undergone by BHXBs that do not reach the thermally dominant accretion state make up a substantial fraction (∼40%) of the Galactic transient BHXB outburst sample over the past ∼20 years. Our findings suggest that this “hard-only” behavior, observed in transient and persistently accreting BHXBs, is neither a rare nor recent phenomenon and may be indicative of an underlying physical process, relatively common among binary BHs, involving the mass-transfer rate onto the BH remaining at a low level rather than increasing as the outburst evolves. We discuss how the larger number of these “hard-only” outbursts and detected outbursts in general have significant implications for both the luminosity function and mass-transfer history of the Galactic BHXB population.

  8. Black holes in short period X-ray binaries and the transition to radiatively inefficient accretion

    NASA Astrophysics Data System (ADS)

    Knevitt, G.; Wynn, G. A.; Vaughan, S.; Watson, M. G.

    2014-02-01

    By comparing the orbital period distributions of black hole and neutron star low-mass X-ray binaries (LMXBs) in the Ritter-Kolb catalogue we show that there is statistical evidence for a dearth of black hole systems at short orbital periods (Porb < 4 h). This could either be due to a true divergence in orbital period distributions of these two types of system, or to black hole LMXBs being preferentially hidden from view at short orbital periods. We explore the latter possibility, by investigating whether black hole LMXBs could be concealed by a switch to radiatively inefficient accretion at low luminosities. The peak luminosity and the duration of X-ray binary outbursts are related to the disc radius and, hence, the orbital period. At short periods, where the peak outburst luminosity drops close to the threshold for radiatively inefficient accretion, black hole LMXBs have lower outburst luminosities, shorter outburst durations and lower X-ray duty cycles than comparable neutron star systems. These factors can combine to severely reduce the detection probability of short period black hole LMXBs relative to those containing neutron stars. We estimate the outburst properties and orbital period distribution of black hole LMXBs using two models of the transition to radiatively inefficient accretion: an instantaneous drop in accretion efficiency (η) to zero, at a fraction (f) of the Eddington luminosity (LEdd) and a power-law efficiency decrease, η ∝ dot{M}^n, for L < f LEdd. We show that a population of black hole LMXBs at short orbital periods can only be hidden by a sharp drop in efficiency, either instantaneous or for n ≳ 3. This could be achieved by a genuine drop in luminosity or through abrupt spectral changes that shift the accretion power out of a given X-ray band.

  9. X-ray Follow-ups of XSS J12270-4859: A Low-mass X-ray Binary with Gamma-ray Fermi-LAT Association

    NASA Technical Reports Server (NTRS)

    deMartino, D.; Belloni, T.; Falanga, M.; Papitto, A.; Motta, S.; Pellizzoni, A.; Evangelista, Y.; Piano, G.; Masetti, N.; Mouchet, M.; Mukai, K.; Possenti, A.

    2013-01-01

    Context. XSS J1227.0-4859 is a peculiar, hard X-ray source recently positionally associated to the Fermi-LAT source 1FGL J1227.9- 4852/2FGL J1227.7-4853. Multi-wavelength observations have added information on this source, indicating a low-luminosity lowmass X-ray binary (LMXB), but its nature is still unclear. Aims. To progress in our understanding, we present new X-ray data from a monitoring campaign performed in 2011 with the XMM-Newton, RXTE, and Swift satellites and combine them with new gamma-ray data from the Fermi and AGILE satellites. We complement the study with simultaneous near-UV photometry from XMM-Newton and with previous UV/optical and near-IR data. Methods. We analysed the temporal characteristics in the X-rays, near-UV, and gamma rays and studied the broad-band spectral energy distribution from radio to gamma rays. Results. The X-ray history of XSS J1227 over 7 yr shows a persistent and rather stable low-luminosity (6 × 1033 d2 1 kpcerg s-1) source, with flares and dips being peculiar and permanent characteristics. The associated Fermi-LAT source 2FGL J1227.7-4853 is also stable over an overlapping period of 4.7 yr. Searches for X-ray fast pulsations down to msec give upper limits to pulse fractional amplitudes of 15-25% that do not rule out a fast spinning pulsar. The combined UV/optical/near-IR spectrum reveals a hot component at approximately 13 kK and a cool one at approximately 4.6 kK. The latter would suggest a late-type K2-K5 companion star, a distance range of 1.4-3.6 kpc, and an orbital period of 7-9 h. A near-UV variability (6 h) also suggests a longer orbital period than previously estimated. Conclusions. The analysis shows that the X-ray and UV/optical/near-IR emissions are more compatible with an accretion-powered compact object than with a rotational powered pulsar. The X-ray to UV bolometric luminosity ratio could be consistent with a binary hosting a neutron star, but the uncertainties in the radio data may also allow an LMXB

  10. Searches for millisecond pulsations in low-mass X-ray binaries, 2

    NASA Technical Reports Server (NTRS)

    Vaughan, B. A.; Van Der Klis, M.; Wood, K. S.; Norris, J. P.; Hertz, P.; Michelson, P. F.; Paradijs, J. Van; Lewin, W. H. G.; Mitsuda, K.; Penninx, W.

    1994-01-01

    Coherent millisecond X-ray pulsations are expected from low-mass X-ray binaries (LMXBs), but remain undetected. Using the single-parameter Quadratic Coherence Recovery Technique (QCRT) to correct for unknown binary orbit motion, we have performed Fourier transform searches for coherent oscillations in all long, continuous segments of data obtained at 1 ms time resolution during Ginga observations of LMXB. We have searched the six known Z sources (GX 5-1, Cyg X-2, Sco X-1, GX 17+2, GX 340+0, and GX 349+2), seven of the 14 known atoll sources (GX 3+1. GX 9+1, GX 9+9, 1728-33. 1820-30, 1636-53 and 1608-52), the 'peculiar' source Cir X-1, and the high-mass binary Cyg X-3. We find no evidence for coherent pulsations in any of these sources, with 99% confidence limits on the pulsed fraction between 0.3% and 5.0% at frequencies below the Nyquist frequency of 512 Hz. A key assumption made in determining upper limits in previous searches is shown to be incorrect. We provide a recipe for correctly setting upper limits and detection thresholds. Finally we discuss and apply two strategies to improve sensitivity by utilizing multiple, independent, continuous segments of data with comparable count rates.

  11. Displacement of X-ray binaries: constraints on the natal kicks

    NASA Astrophysics Data System (ADS)

    Zuo, Zhao-Yu

    2015-01-01

    Context. This work uses the measured luminosity vs. displacement (LX vs. R) distribution of high-mass X-ray binaries (HMXBs) to constrain the dispersion of kick velocity σkick, which is an important parameter affecting the system velocity of a binary, and hence its spatial offset from the point of origin. Aims: The aim is to constrain the natal kicks and discriminate between models by comparing the observed LX vs. R distributions with the theoretical simulations. Methods: Using an up-to-date evolutionary population synthesis technique, the spatial offsets of HMXBs are modeled for a range of theoretical models describing the natal kicks, including different choices of the dispersion of kick velocity σkick, as well as different theoretical treatments for black hole (BH) natal kicks. Results: The study shows that the value of σkick for neutron stars (NSs) is constrained to be greater than ~100 km s-1, while σkick on the order of several tens of km s-1 may be excluded, though a low or absent natal kick for electron capture supernovae NSs is permitted. In particular, BH natal kicks are found not indispensable to account for the LX vs. R distributions. It is more interesting that full BH natal kicks (i.e., similar to those that NSs may receive) are likely to be ruled out in this study, which is in contrast with the recent finding to explain the observed distribution of low-mass X-ray binaries hosting BHs.

  12. X-rays and gamma-rays from accretion flows onto black holes in Seyferts and X-ray binaries

    NASA Technical Reports Server (NTRS)

    Zdziarski, Andrzej A.; Johnson, W. Neil; Poutanen, Juri; Magdziarz, Pawel; Gierlinski, Marek

    1997-01-01

    Observations and theoretical models of X-ray/gamma ray spectra of radio quiet Seyfert galaxies and Galactic black hole candidates are reviewed. The spectra from these objects share the following characteristics: an underlying power law with a high energy cutoff above 200 keV; a Compton reflection component with a Fe K alpha line, and a low energy absorption by intervening cold matter. The X-ray energy spectral index, alpha, is typically in the range between 0.8 and 1 in Seyfert spectra, and that of the hard state spectra of the black hole candidates Cygnus X-1 and GX 339-4 is typically between 0.6 and 0.8. The Compton reflection component corresponds with cold matter covering a solid angle of between 0.8pi and 2pi as seen from the X-ray source. The broadband spectra of both classes of sources are well fitted by Compton upscattering of soft photons in thermal plasma. The fits yield a thermal plasma temperature of 100 keV and the Thomson optical depth of 1. All the spectra presented are cut off before the electron rest energy 511 keV, indicating that electron/positron pair production is an important process.

  13. Phase shifts and nonellipsoidal light curves: Challenges from mass determinations in x-ray binary stars

    NASA Astrophysics Data System (ADS)

    Cantrell, Andrew Glenn

    We consider two types of anomalous observations which have arisen from efforts to measure dynamical masses of X-ray binary stars: (1) Radial velocity curves which seemingly show the primary and the secondary out of antiphase in most systems, and (2) The observation of double-waved light curves which deviate significantly from the ellipsoidal modulations expected for a Roche lobe filling star. We consider both problems with the joint goals of understanding the physical origins of the anomalous observations, and using this understanding to allow robust dynamical determinations of mass in X-ray binary systems. In our analysis of phase-shifted radial velocity curves, we discuss a comprehensive sample of X-ray binaries with published phase-shifted radial velocity curves. We show that the most commonly adopted explanation for phase shifts is contradicted by many observations, and consider instead a generalized form of a model proposed by Smak in 1970. We show that this model is well supported by a range of observations, including some systems which had previously been considered anomalous. We lay the groundwork for the derivation of mass ratios based on our explanation for phase shifts, and we discuss the work necessary to produce more detailed physical models of the phase shift. In our analysis of non-ellipsoidal light curves, we focus on the very well-studied system A0620-00. We present new VIH SMARTS photometry spanning 1999-2007, and supplement this with a comprehensive collection of archival data obtained since 1981. We show that A0620-00 undergoes optical state changes within X-ray quiescence and argue that not all quiescent data should be used for determinations of the inclination. We identify twelve light curves which may reliably be used for determining the inclination. We show that the accretion disk contributes significantly to all twelve curves and is the dominant source of nonellipsoidal variations. We derive the disk fraction for each of the twelve curves

  14. Probing X-ray burst - accretion disk interaction in low mass X-ray binaries through kilohertz quasiperiodic oscillations

    NASA Astrophysics Data System (ADS)

    Peille, P.; Olive, J.-F.; Barret, D.

    2014-07-01

    The intense radiation flux of Type I X-ray bursts is expected to interact with the accretion flow around neutron stars. High frequency quasiperiodic oscillations (kHz QPOs), observed at frequencies matching orbital frequencies at tens of gravitational radii, offer a unique probe of the innermost disk regions. In this paper, we follow the lower kHz QPOs, in response to Type I X-ray bursts, in two prototypical QPO sources, namely 4U 1636-536 and 4U 1608-522, as observed by the Proportional Counter Array of the Rossi X-ray Timing Explorer. We have selected a sample of 15 bursts for which the kHz QPO frequency can be tracked on timescales commensurable with the burst durations (tens of seconds). We find evidence that the QPOs are affected for over ~200 s during one exceptionally long burst and ~100 s during two others (although at a less significant level), while the burst emission has already decayed to a level that would enable the pre-burst QPO to be detected. On the other hand, for most of our burst-kHz QPO sample, we show that the QPO is detected as soon as the statistics allow and in the best cases, we are able to set an upper limit of ~20 s on the recovery time of the QPO. This diversity of behavior cannot be related to differences in burst peak luminosity. We discuss these results in the framework of recent findings that accretion onto the neutron star may be enhanced during Type I X-ray bursts. The subsequent disk depletion could explain the disappearance of the QPO for ~100 s, as possibly observed in two events. However, alternative scenarios would have to be invoked for explaining the short recovery timescales inferred from most bursts. Heating of the innermost disk regions would be a possibility, although we cannot exclude that the burst does not affect the QPO emission at all. Clearly the combination of fast timing and spectral information of Type I X-ray bursts holds great potential in the study of the dynamics of the inner accretion flow around neutron

  15. Probing the clumpy winds of giant stars with high mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Grinberg, Victoria; Hell, Natalie; Hirsch, Maria; Garcia, Javier; Huenemoerder, David; Leutenegger, Maurice A.; Nowak, Michael; Pottschmidt, Katja; Schulz, Norbert S.; Sundqvists, Jon O.; Townsend, Richard D.; Wilms, Joern

    2016-04-01

    Line-driven winds from early type stars are structured, with small, overdense clumps embedded in tenuous hot gas. High mass X-ray binaries (HMXBs), systems where a neutron star or a black hole accretes from the line-driven stellar wind of an O/B-type companion, are ideal for studying such winds: the wind drives the accretion onto the compact object and thus the X-ray production. The radiation from close to the compact object is quasi-pointlike and effectively X-rays the wind.We used RXTE and Chandra-HETG observations of two of the brightest HMXBs, Cyg X-1 and Vela X-1, to decipher their wind structure. In Cyg X-1, we show that the orbital variability of absorption can be only explained by a clumpy wind model and constrain the porosity of the wind as well as the onion-like structure of the clumps. In Vela X-1 we show, using the newest reference energies for low ionization Si-lines obtained with LLNL’s EBIT-I, that the ionized phase of the circumstellar medium and the cold clumps have different velocities.

  16. Evidence for Simultaneous Jets and Disk Winds in Luminous Low-mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Homan, Jeroen; Neilsen, Joseph; Allen, Jessamyn L.; Chakrabarty, Deepto; Fender, Rob; Fridriksson, Joel K.; Remillard, Ronald A.; Schulz, Norbert

    2016-10-01

    Recent work on jets and disk winds in low-mass X-ray binaries (LMXBs) suggests that they are to a large extent mutually exclusive, with jets observed in spectrally hard states and disk winds observed in spectrally soft states. In this paper we use existing literature on jets and disk winds in the luminous neutron star (NS) LMXB GX 13+1, in combination with archival Rossi X-ray Timing Explorer data, to show that this source is likely able to produce jets and disk winds simultaneously. We find that jets and disk winds occur in the same location on the source’s track in its X-ray color-color diagram. A further study of literature on other luminous LMXBs reveals that this behavior is more common, with indications for simultaneous jets and disk winds in the black hole LMXBs V404 Cyg and GRS 1915+105 and the NS LMXBs Sco X-1 and Cir X-1. For the three sources for which we have the necessary spectral information, we find that simultaneous jets/winds all occur in their spectrally hardest states. Our findings indicate that in LMXBs with luminosities above a few tens of percent of the Eddington luminosity, jets and disk winds are not mutually exclusive, and the presence of disk winds does not necessarily result in jet suppression.

  17. The Symbiotic X-ray Binary 3A 1954+319

    NASA Astrophysics Data System (ADS)

    Marcu, Diana; Fuerst, F.; Grieves, N.; Grinberg, V.; Pottschmidt, K.; Postnov, K.; Corbert, R. H. D.; Markwardt, C. B.; Wilms, J.; Miskovicova, I.; Cadolle Bel, M.

    2011-09-01

    We present an analysis of the highly variable X-ray source 3A 1954+319 from 2005 to 2009. We focus on an outburst serendipitously observed during INTEGRAL Key Program observations of the Cygnus region in November 2008 and on the Swift-BAT longterm light curve. The source has been identified to be one of only eight known symbiotic X-ray binaries, systems composed of an accreting neutron star orbiting in a highly inhomogeneous medium around an M-giant companion. Its 3-80 keV spectrum can be described by a broken power law model. The extremely long pulse period of 5.3 hours is clearly visible in the INTEGRAL-ISGRI light curve and confirmed by an epoch folding period search. Furthermore, these light curves allow for the determination of a very strong spin-up of -2 x 10-4 d/d during the 2008 outburst. This is confirmed by the pulse period evolution calculated from Swift-BAT data. Based on these results we discuss a possible wind accretion scenario for this source. In addition, we present a preliminary analysis of high quality data of the soft spectral component of 3A 1954+319 obtained with Chandra and RXTE in 2010/2011 during a relatively stable phase of moderate source brightness, allowing us to further constrain properties of the X-ray source as well as the M-star wind.

  18. The soft X-ray spectrum of the high-mass X-ray binary V0332+53 in quiescence

    NASA Astrophysics Data System (ADS)

    Elshamouty, Khaled G.; Heinke, Craig O.; Chouinard, Rhys

    2016-11-01

    The behaviour of neutron stars in high-mass X-ray binaries (HMXBs) during periods of low mass transfer is of great interest. Indications of spectral softening in systems at low mass-transfer rates suggest that some HMXBs are undergoing fundamental changes in their accretion regime, but the nature of the quiescent X-ray emission is not clear. We performed a 39 ks XMM-Newton observation of the transient HMXB V0332+53, finding it at a very low X-ray luminosity (Lx ˜ 4 × 1032 erg s-1). A power-law spectral fit requires an unusually soft spectral index (4.4^{+0.9}_{-0.6}), while a magnetized neutron star atmosphere model, with temperature LogTeff 6.7 ± 0.2 K and inferred emitting radius of ˜0.2-0.3 km, gives a good fit. We suggest that the quiescent X-ray emission from V0332+53 is mainly from a hotspot on the surface of the neutron star. No conclusions on the presence of pulsations could be drawn due to the low count rate. Due to the high absorption column, thermal emission from the rest of the neutron star could be only weakly constrained, to LogTeff <6.14^{+0.05}_{-6.14} K, or <3 × 1033 erg s-1.

  19. A Chandra X-Ray Observation of the Binary Millisecond Pulsar PSR J1023+0038

    NASA Astrophysics Data System (ADS)

    Bogdanov, Slavko; Archibald, Anne M.; Hessels, Jason W. T.; Kaspi, Victoria M.; Lorimer, Duncan; McLaughlin, Maura A.; Ransom, Scott M.; Stairs, Ingrid H.

    2011-12-01

    We present a Chandra X-Ray Observatory ACIS-S variability, spectroscopy, and imaging study of the peculiar binary containing the millisecond pulsar J1023+0038. The X-ray emission from the system exhibits highly significant (12.5σ) large-amplitude (factor of two to three) orbital variability over the five consecutive orbits covered by the observation, with a pronounced decline in the flux at all energies at superior conjunction. This can be naturally explained by a partial geometric occultation by the secondary star of an X-ray-emitting intrabinary shock, produced by the interaction of outflows from the two stars. The depth and duration of the eclipse imply that the intrabinary shock is localized near or at the surface of the companion star and close to the inner Lagrangian point. The energetics of the shock favor a magnetically dominated pulsar wind that is focused into the orbital plane, requiring close alignment of the pulsar spin and orbital angular momentum axes. The X-ray spectrum consists of a dominant non-thermal component and at least one thermal component, likely originating from the heated pulsar polar caps, although a portion of this emission may be from an optically thin "corona." We find no evidence for extended emission due to a pulsar wind nebula or bow shock down to a limiting luminosity of L X <~ 3.6 × 1029 erg s-1 (0.3-8 keV), <~ 7 × 10-6 of the pulsar spin-down luminosity, for a distance of 1.3 kpc and an assumed power-law spectrum with photon index Γ = 1.5.

  20. Tracing the Lowest Propeller Line in Magellanic High-mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Christodoulou, Dimitris M.; Laycock, Silas G. T.; Yang, Jun; Fingerman, Samuel

    2016-09-01

    We have combined the published observations of high-mass X-ray binary (HMXB) pulsars in the Magellanic Clouds with a new processing of the complete archival data sets from the XMM-Newton and Chandra observatories in an attempt to trace the lowest propeller line below which accretion to polar caps is inhibited by the centrifugal force and the pulsations from the most weakly magnetized pulsars cease. Previously published data reveal that some of the faster-spinning pulsars with spin periods of P S < 12 s, detected at relatively low X-ray luminosities L X , appear to define such a line in the P S -L X diagram, characterized by a magnetic moment of μ = 3 × 1029 G cm3. This value implies the presence of surface magnetic fields of B ≥ 3 × 1011 G in the compact objects of this class. Only a few quiescent HMXBs are found below the propeller line: LXP4.40 and SXP4.78, for which XMM-Newton and Chandra null detections respectively placed firm upper limits on their X-ray fluxes in deep quiescence; and A0538-66, for which many sub-Eddington detections have never measured any pulsations. On the other hand, the data from the XMM-Newton and Chandra archives show clearly that, during routine observation cycles, several sources have been detected below the propeller line in extremely faint, nonpulsating states that can be understood as the result of weak magnetospheric emission when accretion to the poles is centrifugally stalled or severely diminished. We also pay attention to the anomalous X-ray pulsar CXOU J010043.1-721134 that was reported in HMXB surveys. Its pulsations and locations near and above the propeller line indicate that this pulsar could be accreting from a fossil disk.

  1. Modeling X-Ray Binary Evolution in Normal Galaxies: Insights from SINGS

    NASA Technical Reports Server (NTRS)

    Tzanavaris, P.; Fragos, T.; Tremmel, M.; Jenkins, L.; Zezas, A.; Lehmer, B. D.; Hornschemeier, A.; Kalogera, V.; Ptak, A; Basu-Zych, A.

    2013-01-01

    We present the largest-scale comparison to date between observed extragalactic X-ray binary (XRB) populations and theoretical models of their production. We construct observational X-ray luminosity functions (oXLFs) using Chandra observations of 12 late-type galaxies from the Spitzer Infrared Nearby Galaxy Survey (SINGS). For each galaxy, we obtain theoretical XLFs (tXLFs) by combining XRB synthetic models, constructed with the population synthesis code StarTrack, with observational star formation histories (SFHs). We identify highest-likelihood models both for individual galaxies and globally, averaged over the full galaxy sample. Individual tXLFs successfully reproduce about half of oXLFs, but for some galaxies we are unable to find underlying source populations, indicating that galaxy SFHs and metallicities are not well matched and/or XRB modeling requires calibration on larger observational samples. Given these limitations, we find that best models are consistent with a product of common envelope ejection efficiency and central donor concentration approx.. = 0.1, and a 50% uniform - 50% "twins" initial mass-ratio distribution. We present and discuss constituent subpopulations of tXLFs according to donor, accretor and stellar population characteristics. The galaxy-wide X-ray luminosity due to low-mass and high-mass XRBs, estimated via our best global model tXLF, follows the general trend expected from the L(sub X) - star formation rate and L(sub X) - stellar mass relations of Lehmer et al. Our best models are also in agreement with modeling of the evolution both of XRBs over cosmic time and of the galaxy X-ray luminosity with redshift.

  2. X-RAY AND RADIO OBSERVATIONS OF THE MASSIVE STAR-FORMING REGION IRAS 20126+4104

    SciTech Connect

    Montes, V. A.; Hofner, P.; Anderson, C.; Rosero, V.

    2015-08-15

    We present results from Chandra ACIS-I and Karl G. Jansky Very Large Array 6 cm continuum observations of the IRAS 20126+4104 massive star-forming region. We detect 150 X-ray sources within the 17′ × 17′ ACIS-I field, and a total of 13 radio sources within the 9.′2 primary beam at 4.9 GHz. Among these observtions are the first 6 cm detections of the central sources reported by Hofner et al., namely, I20N1, I20S, and I20var. A new variable radio source is also reported. Searching the 2MASS archive, we identified 88 near-infrared (NIR) counterparts to the X-ray sources. Only four of the X-ray sources had 6 cm counterparts. Based on an NIR color–color analysis and on the Besançon simulation of Galactic stellar populations, we estimate that approximately 80 X-ray sources are associated with this massive star-forming region. We detect an increasing surface density of X-ray sources toward the massive protostar and infer the presence of a cluster of at least 43 young stellar objects within a distance of 1.2 pc from the massive protostar.

  3. X Persei: The X-Ray Halo and Spectrum of a High-Latitude X-Ray Binary

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Smith, Randall

    2004-01-01

    The observations were completed on February 25,2003. Although the source was in the FOV for 31.4 ksec, only 18.2 ksec of data were usable due to a strong flare in the first part of the observations. We have extracted the X-ray halo from the good portion of the data, and were then faced with the problem of calibrating the far-off-axis point spread function, which is needed only for X-ray halo analysis; the same problem affected Chandra halo observations. We used data from 3C273, MCG 6-30-15, LMC X-1, and Her X-1 to measure the PSF, and found that it is reasonably well fit with a power law of the form PSF(theta) = A theta^-G, where A = 0.0034 arcmin^-2, and G = 3.05 for energies between 1-4 keV. This suggests there are fewer large dust grains along the When fitting the spectrum of X Persei, we found NH = 3e21 cm^-2, as expected. However, the X-ray halo (using a Mathis, Rumpl, Nordsieck 1977 dust model) required at most a column density of 1.4+/-0.1 e21 cm^-2; other models required sightline to X Per than would have been expected. In addition, a smoothly distributed dust model fit the observations better than a single cloud model, also against our expectations. We are in the process of writing a paper to be submitted to ApJ with these results, and will also present them at the 2004 HEAD meeting in New Orleans.

  4. Multiwavelength monitoring and X-ray brightening of Be X-ray binary PSR J2032+4127/MT91 213 on its approach to periastron

    NASA Astrophysics Data System (ADS)

    Ho, Wynn C. G.; Ng, C.-Y.; Lyne, Andrew G.; Stappers, Ben W.; Coe, Malcolm J.; Halpern, Jules P.; Johnson, Tyrel J.; Steele, Iain A.

    2017-01-01

    The radio and gamma-ray pulsar PSR J2032+4127 was recently found to be in a decades-long orbit with the Be star MT91 213, with the pulsar moving rapidly towards periastron. This binary shares many similar characteristics with the previously unique binary system PSR B1259-63/LS 2883. Here, we describe radio, X-ray, and optical monitoring of PSR J2032+4127/MT91 213. Our extended orbital phase coverage in radio, supplemented with Fermi LAT gamma-ray data, allows us to update and refine the orbital period to 45-50 yr and time of periastron passage to 2017 November. We analyse archival and recent Chandra and Swift observations and show that PSR J2032+4127/MT91 213 is now brighter in X-rays by a factor of ˜70 since 2002 and ˜20 since 2010. While the pulsar is still far from periastron, this increase in X-rays is possibly due to collisions between pulsar and Be star winds. Optical observations of the Hα emission line of the Be star suggest that the size of its circumstellar disc may be varying by ˜2 over time-scales as short as 1-2 months. Multiwavelength monitoring of PSR J2032+4127/MT91 213 will continue through periastron passage, and the system should present an interesting test case and comparison to PSR B1259-63/LS 2883.

  5. The Origin of Warped, Precessing Accretion Disks in X-ray Binaries

    NASA Technical Reports Server (NTRS)

    Maloney, Philip R.; Begelman, Mitchell C.

    1997-01-01

    The radiation-driven warping instability discovered by Pringle holds considerable promise as the mechanism responsible for producing warped, precessing accretion disks in X-ray binaries. This instability is an inherently global mode of the disk, thereby avoiding the difficulties with earlier models for the precession. Here we follow up on earlier work to study the linear behavior of the instability in the specific context of a binary system. We treat the influence of the companion as an orbit-averaged quadrupole torque on the disk. The presence of this external torque allows the existence of solutions in which the direction of precession of the warp is retrograde with respect to disk rotation, in addition to the prograde solutions that exist in the absence of external torques.

  6. Tracing X-ray Binary Population Evolution By Galaxy Dissection: First Results from M51

    NASA Astrophysics Data System (ADS)

    Lehmer, Bret; Eufrasio, Rafael T.; Markwardt, Larissa; Zezas, Andreas; Basu-Zych, Antara; Fragos, Tassos; Hornschemeier, Ann E.; Kalogera, Vassiliki; Ptak, Andrew; Tzanavaris, Panayiotis; Yukita, Mihoko

    2017-01-01

    Recently, we have found, in the Chandra Deep Field-South, that the emission from X-ray binary (XRB) populations in galaxies evolves significantly with cosmic time, most likely due to changes in the physical properties of galaxies like star-formation rate, stellar mass, stellar age, and metallicity. However, it has been challenging to directly show that these same physical properties are connected to XRB populations using data from nearby galaxies. We present a new technique for empirically calibrating how X-ray binary (XRB) populations evolve following their formation in a variety of environments. We first utilize detailed stellar population synthesis modeling of far-UV to far-IR broadband data of nearby (< 10 Mpc) face-on spiral galaxies to construct maps of the star-formation histories on subgalactic scales. Using Chandra data, we then identify the locations of the XRBs within these galaxies and correlate their formation frequencies with local galaxy properties. In this talk, I will show promising first results for the Whirlpool galaxy (M51), and will discuss how expanding our sample to an archival sample of 20 face-on spirals will lead to a detailed empirical timeline for how XRBs form and evolve in various environments.

  7. Unsupervised spectral decomposition of X-ray binaries with application to GX 339-4

    NASA Astrophysics Data System (ADS)

    Koljonen, K. I. I.

    2015-03-01

    In this paper, we explore unsupervised spectral decomposition methods for distinguishing the effect of different spectral components for a set of consecutive spectra from an X-ray binary. We use well-established linear methods for the decomposition, namely principal component analysis, independent component analysis and non-negative matrix factorization (NMF). Applying these methods to a simulated data set consisting of a variable multicolour disc blackbody and a cutoff power law, we find that NMF outperforms the other two methods in distinguishing the spectral components. In addition, due the non-negative nature of NMF, the resulting components may be fitted separately, revealing the evolution of individual parameters. To test the NMF method on a real source, we analyse data from the low-mass X-ray binary GX 339-4 and found the results to match those of previous studies. In addition, we found the inner radius of the accretion disc to be located at the innermost stable circular orbit in the intermediate state right after the outburst peak. This study shows that using unsupervised spectral decomposition methods results in detecting the separate component fluxes down to low flux levels. Also, these methods provide an alternative way of detecting the spectral components without performing actual spectral fitting, which may prove to be practical when dealing with large data sets.

  8. Timing the Beast: A Spectro-Timing Approach to Understanding X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Grinberg, Victoria; Pottschmidt, Katja; Böck, Moritz; Schmid, Christian; Uttley, Phil; Tomsick, John; Rodriguez, Jerome; Hell, Natalie; Markowitz, Alex; Bodaghee, Arash; Cadolle Bel, Marion; Rothschild, Richard E.; Wilms, Joern

    2014-08-01

    Neither spectral nor timing studies alone allow us to disentangle the complex interplay of accretion and ejection processes. In this talk, I will show how combining both methods allows for an (almost) model-independent description of X-ray binary behavior across different accretion and ejection regimes and gives clues as to the contributions of accretion disk, disk winds, jets and Comptonization corona to the X-ray spectrum. A better grasp of the long-term evolution is also crucial for the interpretation of individual high resolution observations, e.g., by Chandra.As an example, we use over 12 years of RXTE monitoring of the black hole Cygnus X-1 to build up a template of spectro-timing behavior which enables an easy comparison among accreting sources acting on different mass and time scales. In particular, we can avoid misidentification of power spectral components in other black hole binaries that are less well sampled and therefore do not allow tracking of power spectral components across spectral states. Important is also the comparison with AGN, where many of the relevant variability time scales that shape the interaction of the supermassive black hole with its surroundings are not accessible during an astronomer's lifetime.

  9. AN ULTRACOMPACT X-RAY BINARY IN THE GLOBULAR CLUSTER NGC 1851

    SciTech Connect

    Zurek, D. R.; Knigge, C.; Maccarone, T. J.; Dieball, A.; Long, K. S.

    2009-07-10

    We present far-ultraviolet photometry obtained with the Hubble Space Telescope of the low-mass X-ray binary 4U 0513-40 in the globular cluster NGC 1851. Our observations reveal a clear, roughly sinusoidal periodic signal with P {approx_equal} 17 minutes and amplitude 3%-10%. The signal appears fully coherent and can be modeled as a simple reprocessing effect associated with the changing projected area presented by the irradiated face of a white dwarf donor star in the system. All of these properties suggest that the signal we have detected is orbital in nature, thus confirming 4U 0513-40 as an ultracompact X-ray binary (UCXB). All four confirmed UCXBs in globular clusters have orbital periods below 30 minutes, whereas almost all UCXBs in the Galactic field have orbital periods longer than this. This suggests that dynamical formation processes dominate UCXB production in clusters, producing a different orbital period distribution than observed among field UCXBs. Based on the likely system parameters, we show that 4U 0513-40 should be a strong gravitational wave source and may be detectable by Laser Interferometer Space Antenna over the course of a multiyear mission.

  10. OPTICAL SPECTROSCOPY OF 20 Be/X-RAY BINARIES IN THE SMALL MAGELLANIC CLOUD

    SciTech Connect

    Antoniou, V.; Hatzidimitriou, D.; Zezas, A.; Reig, P.

    2009-12-20

    We present a large sample (20 in total) of optical spectra of Small Magellanic Cloud (SMC) High-Mass X-ray Binaries obtained with the 2dF spectrograph at the Anglo-Australian Telescope. All of these sources are found to be Be/X-ray binaries (Be-XRBs), while for five sources we present original classifications. Several statistical tests on this expanded sample support previous findings for similar spectral-type distributions of Be-XRBs and Be field stars in the SMC, and of Be-XRBs in the Large Magellanic Cloud and the Milky Way, although this could be the result of small samples. On the other hand, we find that Be-XRBs follow a different distribution than Be stars in the Galaxy, also in agreement with previous studies. In addition, we find similar Be spectral-type distributions between the Magellanic Clouds samples. These results reinforce the relation between the orbital period and the equivalent width of the Halpha line that holds for Be-XRBs. SMC Be stars have larger Halpha equivalent widths when compared to Be-XRBs, supporting the notion of circumstellar disk truncation by the compact object.

  11. A High-Precision, Optical Polarimeter to Measure Inclinations of High Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Wiktorowicz, Sloane; Matthews, K.; Kulkarni, S. R.

    2007-12-01

    While most astrophysical objects require many parameters in order to be fully described, black holes are unique in that only three parameters are required: mass, spin, and charge. Of these, mass and spin are enough to describe the black hole's gravitational field and event horizon location. Therefore, theory and observation may jointly pursue one or two quantities to uncover the progenitor star's history. Constraints on black hole mass exist for high mass X-ray binaries, such as Cygnus X-1, which is thought to consist of a 40 ± 10 solar mass O9.7Iab star and a 13.5-29 solar mass black hole (Ziolkowski 2005). While the constraints on the mass of the compact object are tight enough to declare that it is a black hole, they are sufficiently loose as to prohibit precise modeling of the progenitor star's mass. We have built an optical polarimeter for the Hale 5-m telescope at Mt. Palomar to provide an independent method for determining black hole mass. Degree of polarization will vary for an edge-on system, while position angle of net polarization will vary for a face-on system. Therefore, by monitoring the linear polarimetric variability of the binary, inclination can be estimated. Coupled with the known mass function of the binary from radial velocity work (Gies et al. 2003), inclination estimates constrain the mass of the black hole. Our polarimeter, POLISH (POLarimeter for Inclination Studies of High mass x-ray binaries), has achieved linear polarimetric precision of less than 10 parts per million on bright, unpolarized standard stars. We will also present results for polarized standard stars and Cygnus X-1 itself. This instrument has been funded by an endowment from the Moore Foundation.

  12. High Resolution Studies of Mass Loss from Massive Binary Stars

    NASA Astrophysics Data System (ADS)

    Corcoran, Michael F.; Gull, Theodore R.; Hamaguchi, Kenji; Richardson, Noel; Madura, Thomas; Post Russell, Christopher Michael; Teodoro, Mairan; Nichols, Joy S.; Moffat, Anthony F. J.; Shenar, Tomer; Pablo, Herbert

    2017-01-01

    Mass loss from hot luminous single and binary stars has a significant, perhaps decisive, effect on their evolution. The combination of X-ray observations of hot shocked gas embedded in the stellar winds and high-resolution optical/UV spectra of the cooler mass in the outflow provides unique ways to study the unstable process by which massive stars lose mass both through continuous stellar winds and rare, impulsive, large-scale mass ejections. The ability to obtain coordinated observations with the Hubble Space Telescope Imaging Spectrograph (HST/STIS) and the Chandra High-Energy Transmission Grating Spectrometer (HETGS) and other X-ray observatories has allowed, for the first time, studies of resolved line emisssion over the temperature range of 104- 108K, and has provided observations to confront numerical dynamical models in three dimensions. Such observations advance our knowledge of mass-loss asymmetries, spatial and temporal variabilities, and the fundamental underlying physics of the hot shocked outflow, providing more realistic constraints on the amount of mass lost by different luminous stars in a variety of evolutionary stages. We discuss the impact that these joint observational studies have had on our understanding of dynamical mass outflows from massive stars, with particular emphasis on two important massive binaries, Delta Ori Aa, a linchpin of the mass luminosity relation for upper HRD main sequence stars, and the supermassive colliding wind binary Eta Carinae.

  13. MAXI/GSC detection of a possible X-ray flare from an dMe binary system YY Gem

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Kanetou, S.; Tsuboi, Y.; Sasaki, R.; Ueno, S.; Tomida, H.; Nakahira, S.; Kimura, M.; Ishikawa, M.; Nakagawa, Y. E.; Mihara, T.; Sugizaki, M.; Serino, M.; Shidatsu, M.; Sugimoto, J.; Takagi, T.; Matsuoka, M.; Kawai, N.; Arimoto, M.; Yoshii, T.; Tachibana, Y.; Ono, Y.; Fujiwara, T.; Yoshida, A.; Sakamoto, T.; Kawakubo, Y.; Ohtsuki, H.; Tsunemi, H.; Imatani, R.; Negoro, H.; Nakajima, M.; Tanaka, K.; Masumitsu, T.; Ueda, Y.; Kawamuro, T.; Hori, T.; Yamauchi, M.; Itoh, D.; Yamaoka, K.; Morii, M.

    2015-09-01

    MAXI/GSC observed a possible X-ray flare from a dMe binary system YY Gem. The MAXI/GSC nova alert system triggered on the flare-like event from the position consistent with the active binary system YY Gem during a scan transit at 01:29:00 UT on September 24th 2015.

  14. X-Ray Spectra of the High-mass X-Ray Binary 4U 1700-37 Using BeppoSAX, Suzaku, and RXTE Observations

    NASA Astrophysics Data System (ADS)

    Seifina, Elena; Titarchuk, Lev; Shaposhnikov, Nikolai

    2016-04-01

    We present an X-ray spectral analysis of the high-mass binary 4U 1700-37 during its hard-soft state evolution. We use BeppoSAX, Suzaku, and Rossi X-ray Timing Explorer observations for this investigation. We argue that the X-ray broadband spectra during all of the spectral states can be adequately reproduced by a model consisting of a low-temperature blackbody component, two Comptonized components which are both due to the presence of a Compton cloud (CC) that up-scatters seed photons of Ts1 ≲ 1.4 keV and Ts2 < 1 keV, and an iron-line component. Using this model, we find that the photon power-law index is almost constant, Γ1 ∼ 2 for all spectral states. However, Γ2 shows behavior that is dependent on the spectral state. Namely, Γ2 is quasi-constant at the level of Γ2 ∼ 2 while the CC plasma temperature {{kT}}e(2) is less than 40 keV; on the other hand, Γ2 is in the range of 1.3 < Γ2 < 2 when {{kT}}e(2) is greater than 40 keV. We explain this quasi-stability of Γ during most of the hard-soft transitions of 4U 1700-37 in the framework of a model in which the resulting spectrum is described by two Comptonized components. We find that these Comptonized spectral components of the high-mass X-ray binaries 4U 1700-37 are similar to those previously found in neutron star (NS) sources. This index dependence versus both the mass accretion rate and kTe revealed in 4U 1700-37 is universal observational evidence for the presence of an NS in 4U 1700-37.

  15. THE X-RAY LUMINOSITY FUNCTION OF LOW MASS X-RAY BINARIES IN EARLY-TYPE GALAXIES, THEIR METAL-RICH, AND METAL-POOR GLOBULAR CLUSTERS

    SciTech Connect

    Peacock, Mark B.; Zepf, Stephen E.

    2016-02-10

    We present the X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXBs) in the globular clusters (GCs) and fields of seven early-type galaxies. These galaxies are selected to have both deep Chandra observations, which allow their LMXB populations to be observed to X-ray luminosities of 10{sup 37}–10{sup 38} erg s{sup −1}, and Hubble Space Telescope optical mosaics that enable the X-ray sources to be separated into field LMXBs, GC LMXBs, and contaminating background and foreground sources. We find that at all luminosities the number of field LMXBs per stellar mass is similar in these galaxies. This suggests that the field LMXB populations in these galaxies are not effected by the GC specific frequency, and that properties such as binary fraction and the stellar initial mass function are either similar across the sample or change in a way that does not affect the number of LMXBs. We compare the XLF of the field LMXBs to that of the GC LMXBs and find that they are significantly different with a p-value of 3 × 10{sup −6} (equivalent to 4.7σ for a normal distribution). The difference is such that the XLF of the GC LMXBs is flatter than that of the field LMXBs, with the GCs hosting relatively more bright sources and fewer faint sources. A comparison of the XLF of the metal-rich and metal-poor GCs hints that the metal-poor clusters may have more bright LMXBs, but the difference is not statistically significant.

  16. MS 1603.6 + 2600, an unusual X-ray selected binary system at high Galactic latitude

    NASA Technical Reports Server (NTRS)

    Morris, Simon L.; Liebert, James; Stocke, John T.; Gioia, Isabella M.; Schild, Rudy E.

    1990-01-01

    The discovery of an eclipsing binary system at Galactic latitude 47 deg, found as a serendipitous X-ray source in the Einstein Extended Medium Sensitivity Survey, is described. The object has X-ray flux 1.1 x 10 to the -12th ergs/sq cm s (0.3-3.5 keV) and mean magnitude R = 19.4. An orbital period of 111 minutes is found. The problem discussed is whether the system has a white dwarf or neutron star primary, in the end preferring the neutron star primary model. If the system has either optical or X-ray luminosities typical of low mass X-ray binaries (LMXB), it must be at a very large distance (30-80 kpc). Blueshifted He I absorption is seen, indicating cool outflowing material, similar to that seen in the LMXB AC 211 in the globular cluster M15.

  17. Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54

    NASA Astrophysics Data System (ADS)

    Reig, P.; Torrejón, J. M.; Negueruela, I.; Blay, P.; Ribó, M.; Wilms, J.

    2009-02-01

    Context: The source 4U 2206+54 is one of the most enigmatic high-mass X-ray binaries. In spite of intensive searches, X-ray pulsations have not been detected in the time range 10-3-103 s. A cyclotron line at ~30 keV has been suggested by various authors but never detected with significance. The stellar wind of the optical companion is abnormally slow. The orbital period, initially reported to be 9.6 days, disappeared and a new periodicity of 19.25 days emerged. Aims: The main objective of our RXTE monitoring of 4U 2206+54 is to study the X-ray orbital variability of the spectral and timing parameters. The new long and uninterrupted RXTE observations allow us to search for long (~1 h) pulsations for the first time. Methods: We divided the ~7-day observation into five intervals and obtained time-averaged energy spectra and power spectral density for each observation interval. We also searched for pulsations using various algorithms. Results: We have discovered 5560-s pulsations in the light curve of 4U 2206+54. Initially detected in RXTE data, these pulsations are also present in INTEGRAL and EXOSAT observations. The average X-ray luminosity in the energy range 2-10 keV is 1.5 × 1035 erg s-1 with a ratio F_max/F_min ≈ 5. This ratio implies an eccentricity of ~0.4, somewhat higher than previously suggested. The power spectrum is dominated by red noise that can be fitted with a single power law whose index and strength decrease with X-ray flux. The source also shows a soft excess at low energies. If the soft excess is modelled with a blackbody component, then the size and temperature of the emitting region agrees with its interpretation in terms of a hot spot on the neutron star surface. Conclusions: The discovery of X-ray pulsations in 4U 2206+54 confirms the neutron star nature of the compact companion and definitively rules out the presence of a black hole. The source displays variability on time scales of days, presumably due to changes in the mass accretion

  18. An X-ray and radio study of the massive star-forming cluster IRAS 20126+4104

    NASA Astrophysics Data System (ADS)

    Montes, Virginie; Hofner, Peter; Anderson, Crystal; Rosero, Viviana

    2015-08-01

    Two main competitive theories intent to explain massive star formation: the turbulent core model, which is an extension of the low-mass star formation model (McKee & Tan 2003), and models involving competitive accretion or stellar collisions (Bonnell & Bate 2006). The characterization of the cluster in which massive stars remain can help discriminate between the two main scenarios of their formation.Until recently it was believed that massive stars were only formed in dense molecular clouds leading to a substantial cluster. However, a previous study of the massive star forming region IRAS 20126+4104 using Spitzer observations by Qiu et al. (2008), suggested that the massive protostar was isolated, and the region was showing no obvious cluster.Here we adopt a multiwavelength technique to characterize the stellar environment of the IRAS 20126+4104 region combining Chandra X-ray ACIS-I and VLA 6cm continuum observations, and near-infrared (2MASS) data of the region. We detected 150 X-ray sources in the ACIS-I field and 13 radio sources within the 9’.2 VLA primary beam. Associating X-ray sources with their near-infrared counterparts from the 2MASS catalog and a color study of those counterparts, allow us to determine the galactic foreground/background contamination, and we conclude that 90 X-ray sources are associated with the region.This study shows an increasing surface density of X-ray sources toward the massive protostar and a number of at least 42 YSOs within 1.2 pc distance from the massive protostar. This number is consistent with typical B-type stars clusters (Lada & Lada 2003).

  19. The Discovery of a Second Luminous Low Mass X-Ray Binary System in the Globular Cluster M15

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Angelini, Lorella

    2001-01-01

    Using the Chandra X-ray Observatory we have discovered a second bright X-ray source in the globular cluster M15 that is 2.7" to the west of AC211, the previously known low mass X-ray binary (LMXB) in this system. Prior to the 0.5" imaging capability of Chandra this second source could not have been resolved from AC211. The luminosity and spectrum of this new source, which we call M15-X2, are consistent with it also being a LMXB system. This is the first time that two LMXBs have been seen to be simultaneously active in a globular cluster. The new source, M15-X2, is coincident with a 18th U magnitude very blue star. The discovery of a second LMXB in M15 clears up a long standing puzzle where the X-ray and optical properties of AC211 appear consistent with the central source being hidden behind an accretion disk corona, and yet also showed a luminous X-ray burst suggesting the neutron star is directly visible. This discovery suggests instead that the X-ray burst did not come from AC211, but rather from the newly discovered X-ray source. We discuss the implications of this discovery for X-ray observations of globular clusters in nearby galaxies.

  20. 2S 1553-542: a Be/X-ray binary pulsar on the far side of the Galaxy

    NASA Astrophysics Data System (ADS)

    Lutovinov, Alexander A.; Buckley, David A. H.; Townsend, Lee J.; Tsygankov, Sergey S.; Kennea, Jamie

    2016-11-01

    We report the results of a comprehensive analysis of X-ray (Chandra and Swift observatories), optical (Southern African Large Telescope, SALT) and near-infrared (the VVV survey) observations of the Be/X-ray binary pulsar 2S 1553-542. Accurate coordinates for the X-ray source are determined and are used to identify the faint optical/infrared counterpart for the first time. Using VVV and SALTICAM photometry, we have constructed the spectral energy distribution (SED) for this star and found a moderate NIR excess that is typical for Be stars and arises due to the presence of circumstellar material (disc). A comparison of the SED with those of known Be/X-ray binaries has allowed us to estimate the spectral type of the companion star as B1-2V and the distance to the system as >15 kpc. This distance estimation is supported by the X-ray data and makes 2S 1553-542 one of the most distant X-ray binaries within the Milky Way, residing on the far side in the Scutum-Centaurus arm or even further.

  1. A study of diffuse radio sources and X-ray emission in six massive clusters

    NASA Astrophysics Data System (ADS)

    Parekh, V.; Dwarakanath, K. S.; Kale, R.; Intema, H.

    2017-01-01

    The goal of this study is to extend our current knowledge of the diffuse radio source (halo and relic) populations to z > 0.3. Here, we report GMRT and EVLA radio observations of six galaxy clusters taken from the MAssive Cluster Survey (MACS) catalogue to detect diffuse radio emission. We used archival GMRT (150, 235, and 610 MHz) and EVLA (L band) data and made images at multiple radio frequencies of the following six clusters - MACSJ0417.5-1154, MACSJ1131.8-1955, MACSJ0308.9+2645, MACSJ2243.3-0935, MACSJ2228.5+2036, and MACSJ0358.8-2955. We detect diffuse radio emission (halo or relic, or both) in the first four clusters. In the last two clusters, we do not detect any diffuse radio emission but we put stringent upper limits on their radio powers. We also use archival Chandra X-ray data to carry out morphology and substructure analysis of these clusters. We find that based on X-ray data, these MACS clusters are non-relaxed and show substructures in their temperature distribution. The radio powers of the first four MACS clusters are consistent with their expected values in the LX-P1.4 GHz plot. However, we found ultrasteep spectrum radio halo in the MACSJ0417.5-1154 cluster whose rest-frame cut-off frequency is at ˜900 MHz. The remaining two clusters whose radio powers are ˜11 times below the expected values are most likely to be in the `off-state' as has been postulated in some of the models of radio halo formation.

  2. High-Mass X-ray Binaries in our Backyard: Studying Their Formation and Evolution in the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Antoniou, Vallia

    2013-04-01

    Our nearest star-forming galaxy, the Large Magellanic Cloud (LMC), offers unique insights into the observational characteristics of young (<100 Myr) X-ray binaries (XRBs) in other distant star-forming galaxies for which these faint luminosity levels are out of reach. The number of currently known High-Mass X-ray Binaries (HXMBs) in this galaxy 40) allows the investigation of the parameters affecting their formation, such as the star-formation rate, the age of the parent stellar populations and the metallicity. Most importantly though, it allows for a direct comparison with the well-studied population of HMXBs in the Small Magellanic Cloud (SMC). We find that the HMXBs (and as expected the X-ray pulsars) are shown in regions with star-formation rate bursts ~6-25 Myr ago, in contrast to the SMC, for which this population peaks at later ages 25-60 Myr ago), a direct result of the younger parent stellar populations in the LMC. Although the SMC is widely believed to have lower metallicity than the LMC 1/5Zsun and ~1/3Zsun, respectively), in this work we have used the available star-formation history for the youngest stellar populations, even if this resulted in the same metallicity 1/2Zsun for Zsun=0.0134) for the HMXB populations in both Magellanic Clouds, thus in this work we do not investigate directly the effect of metallicity. Using the mean offset between each HMXB and its nearest star cluster, we estimate the distance that the HMXBs may have travelled since birth. Although the HMXBs in the LMC seem to travel twice as large distances as their counterparts in the SMC, at the same time they are significantly younger than the HMXBs in the SMC (i.e. with ages of ~6-25 Myr and ~25-60 Myr, respectively). For this reason, we derive similar kick velocities for the HMXBs in both galaxies, which are also in agreement with values estimated for the Galactic systems 10-20 km/s). The young XRBs are tracers of past populations of massive stars, while the study of their compact

  3. Population synthesis of classical low-mass X-ray binaries in the Galactic Bulge

    NASA Astrophysics Data System (ADS)

    van Haaften, L. M.; Nelemans, G.; Voss, R.; van der Sluys, M. V.; Toonen, S.

    2015-07-01

    Aims: We model the present-day population of classical low-mass X-ray binaries (LMXBs) with neutron star accretors, which have hydrogen-rich donor stars. Their population is compared with that of hydrogen-deficient LMXBs, known as ultracompact X-ray binaries (UCXBs). We model the observable LMXB population and compare it to observations. We model the Galactic Bulge because it contains a well-observed population and it is the target of the Galactic Bulge Survey. Methods: We combine the binary population synthesis code SeBa with detailed LMXB evolutionary tracks to model the size and properties of the present-day LMXB population in the Galactic Bulge. Whether sources are persistent or transient, and what their instantaneous X-ray luminosities are, is predicted using the thermal-viscous disk instability model. Results: We find a population of ~2.1 × 103 LMXBs with neutron star accretors. Of these about 15-40 are expected to be persistent (depending on model assumptions), with luminosities higher than 1035 erg s-1. About 7-20 transient sources are expected to be in outburst at any given time. Within a factor of two these numbers are consistent with the observed population of bright LMXBs in the Bulge. This gives credence to our prediction of the existence of a population of ~1.6 × 103 LMXBs with low donor masses that have gone through the period minimum, and have present-day mass transfer rates below 10-11 M⊙ yr-1. Conclusions: Even though the observed population of hydrogen-rich LMXBs in the Bulge is larger than the observed population of (hydrogen-deficient) UCXBs, the latter have a higher formation rate. While UCXBs may dominate the total LMXB population at the present time, the majority would be very faint or may have become detached and produced millisecond radio pulsars. In that case UCXBs would contribute significantly more to the formation of millisecond radio pulsars than hydrogen-rich LMXBs.

  4. RXJ0440.9+4431: a Persistent Be-x-ray Binary in Outburst

    NASA Technical Reports Server (NTRS)

    Ferrigno, C.; Farinelli, R.; Bozzo, E.; Pottschmidt, K.; Klochkov, D.; Kretschmar, P.

    2013-01-01

    The persistent Be/X-ray binary RXJ0440.9+4431 flared in 2010 and 2011 and has been followed by various X-ray facilities (Swift, RXTE, XMM-Newton, and INTEGRAL).We studied the source timing and spectral properties as a function of its X-ray luminosity to investigate the transition from normal to flaring activity and the dynamical properties of the system. We have determined the orbital period from the long-term Swift/BAT light curve, but our determinations of the spin-period are not precise enough to constrain any orbital solution. The source spectrum can always be described by a bulk-motion Comptonization model of black body seed photons attenuated by a moderate photoelectric absorption. At the highest luminosity, we measured a curvature of the spectrum, which we attribute to a significant contribution of the radiation pressure in the accretion process. This allows us to estimate that the transition from a bulk-motion-dominated flow to a radiatively dominated one happens at a luminosity of approx 2 × 10(exp 36) erg/ s. The luminosity dependency of the size of the black body emission region is found to be r(sub BB) varies as L(sub x) (exp 0.39 +/- 0.02). This suggests that either matter accreting onto the neutron star hosted in RXJ0440.9+4431 penetrates through closed magnetic field lines at the border of the compact object magnetosphere or that the structure of the Neutron star magnetic field is more complicated than a simple dipole close to the surface.

  5. A study of coronal X-ray emission from short-period Algol binaries

    NASA Technical Reports Server (NTRS)

    Singh, K. P.; Drake, S. A.; White, N. E.

    1995-01-01

    A study of X-ray emission from five short-period Algol-type binaries based on observations with Advanced Satellite for Cosmology and Astrophysics (ASCA) and ROSAT is presented. We have observed RZ Cas with both satellites, and beta Per, U Cep, delta Lib, and TW Dra with ROSAT. Significant intensity variations are seen in the X-ray emission from RZ Cas, U Cep, TW Dra, and delta Lib. These variations seem unrelated to the eclipsing behavior of these systems and are probably due to either rotational modulation of compact active regions on the surfaces of the chromospherically active secondary components or to flaring activity in the systems. The spectra of all but one of the systems require the presence of at least two discrete plasma components with different temperatures (0.6 - 0.7 keV, and approximately 2 keV) and the abundances of the medium-Z elements 20% - 50% of the solar photospheric values. The high resolving power and signal-to-noise ratio of the ASCA spectra allow us to individually constrain the coronal abundances of O, Ne, Mg, Si, S, and Fe in RZ Cas. We demonstrate that, if we use the elemental abundances and temperatures obtained from the analysis of their ASCA spectra as (fixed) inputs, to fit the ROSAT PSPC spectra well requires the presence of a third component (kT approximately 0.2 - 0.3 keV) in RZ Cas and beta Per. A continuous emission measure model of the power-law type (EM(T) variesas (T/T(sub max)(sup alpha)) generally gives a poor fit to the ASCA and ROSAT data on most sources. Circumstellar or circumbinary absorbing matter seems to be present in some of these systems, as indicated by the variable total column density needed to fit their X-ray spectra.

  6. INTEGRAL Observations of the Be/X-ray binary EX0 2030+375 During Outburst

    NASA Technical Reports Server (NTRS)

    Arranz, A. Camero; Wilson, C. A.; Connell, P.; Nunez, S. Martinez; Blay, P.; Beckmann, V.; Reglero, V.

    2005-01-01

    We present a type-I outburst of the high-mass X-ray binary EX0 2030+375, detected during INTEGRAL'S Performance and Verification phase in December 2002 (on-source time about 10(exp 6) seconds). In addition, six more outbursts have been observed during INTEGRAL'S Galactic Plane Scans. X-ray pulsations have been detected with a pulse period of 41.691798 plus or minus 0.000016 s. The X-ray luminosity in the 5-300 keV energy range was 9.7 x 10 (exp 36) erg per second, for a distance of 7.1 kpc. Two unusual features were found in the light curve, with an initial peak before the main outburst and another possible spike after the maximum. RXTE observations confirm only the existence of the initial spike. Although the initial peak appears to be a recurrent feature, the physical mechanisms producing it and the possible second spike are unknown. Moreover, a four-day delay between periastron passage and the peak of the outburst is observed. We present for the first time a 5-300 keV broad-band spectrum of this source. It can be modelled by the sum of a disk black body (kT(sub BB) approximately 8 keV) and either with a power law model with Gamma=2.04 plus or minus 0.11 keV or a Comptonized component (spherical geometry, kT(sub e).=30 keV, tau = 2.64, kT(sub w)=1.5 keV).

  7. THE AGES OF HIGH-MASS X-RAY BINARIES IN NGC 2403 AND NGC 300

    SciTech Connect

    Williams, Benjamin F.; Binder, Breanna A.; Dalcanton, Julianne J.; Eracleous, Michael; Dolphin, Andrew E-mail: bbinder@astro.washington.edu E-mail: mce@astro.psu.edu

    2013-07-20

    We have examined resolved stellar photometry from HST imaging surrounding 18 high-mass X-ray binary (HMXB) candidates in NGC 300 and NGC 2403 as determined from combined Chandra/HST analysis. We have fit the color-magnitude distribution of the surrounding stars with stellar evolution models. All but one region in NGC 300 and two in NGC 2403 contain a population with an age between 20 and 70 Myr. One of the candidates is the ultraluminous X-ray source in NGC 2403, which we associate with a 60 {+-} 5 Myr old population. These age distributions provide additional evidence that 16 of these 18 candidates are HMXBs. Furthermore, our results suggest that the most common HMXB age in these galaxies is 40-55 Myr. This preferred age is similar to observations of HMXBs in the Small Magellanic Cloud, providing new evidence of this formation timescale, but in higher metallicity populations. We suggest that this preferred HMXB age is the result of the fortuitous combination of two physical effects. First, this is the age of a population when the greatest rate of core-collapse events should be occurring, maximizing neutron star production. Second, this is the age when B stars are most likely to be actively losing mass. We also discuss our results in the context of HMXB feedback in galaxies, confirming HMXBs as a potentially important source of energy for the interstellar medium in low-mass galaxies.

  8. THE EFFECT OF STARBURST METALLICITY ON BRIGHT X-RAY BINARY FORMATION PATHWAYS

    SciTech Connect

    Linden, T.; Kalogera, V.; Sepinsky, J. F.; Prestwich, A.; Zezas, A.; Gallagher, J. S.

    2010-12-20

    We investigate the characteristics of young (<20 Myr) and bright (L{sub X} > 1 x 10{sup 36} erg s{sup -1}) high-mass X-ray binaries (HMXBs) and find the population to be strongly metallicity dependent. We separate the model populations among two distinct formation pathways: (1) systems undergoing active Roche lobe overflow (RLO) and (2) wind accretion systems with donors in the (super)giant stage, which we find to dominate the HMXB population. We find metallicity to primarily affect the number of systems which move through each formation pathway, rather than the observable parameters of systems which move through each individual pathway. We discuss the most important model parameters affecting the HMXB population at both low and high metallicities. Using these results, we show that (1) the population of ultra-luminous X-ray sources can be consistently described by very bright HMXBs which undergo stable RLO with mild super-Eddington accretion and (2) the HMXB population of the bright starburst galaxy NGC 1569 is likely dominated by one extremely metal-poor starburst cluster.

  9. Exploring X-Ray Binary Populations in Compact Group Galaxies With Chandra

    NASA Technical Reports Server (NTRS)

    Tzanavaris, P.; Hornschemeier, A. E..; Gallagher, S. C.; Lenkic, L.; Desjardins, T. D.; Walker, L. M.; Johnson, K. E.; Mulchaey, J. S.

    2016-01-01

    We obtain total galaxy X-ray luminosities, LX, originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the great majority of our galaxies, we find that the detected point sources most likely are local to their associated galaxy, and are thus extragalactic X-ray binaries (XRBs) or nuclear active galactic nuclei (AGNs). For spiral and irregular galaxies, we find that, after accounting for AGNs and nuclear sources, most CG galaxies are either within the +/-1s scatter of the Mineo et al. LX-star formation rate (SFR) correlation or have higher LX than predicted by this correlation for their SFR. We discuss how these "excesses" may be due to low metallicities and high interaction levels. For elliptical and S0 galaxies, after accounting for AGNs and nuclear sources, most CG galaxies are consistent with the Boroson et al. LX-stellar mass correlation for low-mass XRBs, with larger scatter, likely due to residual effects such as AGN activity or hot gas. Assuming non-nuclear sources are low- or high-mass XRBs, we use appropriate XRB luminosity functions to estimate the probability that stochastic effects can lead to such extreme LX values. We find that, although stochastic effects do not in general appear to be important, for some galaxies there is a significant probability that high LX values can be observed due to strong XRB variability.

  10. Discovery of the third transient X-ray binary in the galactic globular cluster Terzan 5

    SciTech Connect

    Bahramian, Arash; Heinke, Craig O.; Sivakoff, Gregory R.; Gladstone, Jeanette C.; Altamirano, Diego; Wijnands, Rudy; Homan, Jeroen; Linares, Manuel; Degenaar, Nathalie

    2014-01-10

    We report and study the outburst of a new transient X-ray binary (XRB) in Terzan 5, the third detected in this globular cluster, Swift J174805.3-244637 or Terzan 5 X-3. We find clear spectral hardening in Swift/XRT data during the outburst rise to the hard state, thanks to our early coverage (starting at L{sub X} ∼ 4 × 10{sup 34} erg s{sup –1}) of the outburst. This hardening appears to be due to the decline in relative strength of a soft thermal component from the surface of the neutron star (NS) during the rise. We identify a Type I X-ray burst in Swift/XRT data with a long (16 s) decay time, indicative of hydrogen burning on the surface of the NS. We use Swift/BAT, MAXI/GSC, Chandra/ACIS, and Swift/XRT data to study the spectral changes during the outburst, identifying a clear hard-to-soft state transition. We use a Chandra/ACIS observation during outburst to identify the transient's position. Seven archival Chandra/ACIS observations show evidence for variations in Terzan 5 X-3's nonthermal component but not the thermal component during quiescence. The inferred long-term time-averaged mass accretion rate, from the quiescent thermal luminosity, suggests that if this outburst is typical and only slow cooling processes are active in the NS core, such outbursts should recur every ∼10 yr.

  11. OBSERVATIONS OF THE HIGH-MASS X-RAY BINARY A 0535+26 IN QUIESCENCE

    SciTech Connect

    Rothschild, Richard; Markowitz, Alex; Hemphill, Paul; Caballero, Isabel; Kuehnel, Matthias; Wilms, Joern; Fuerst, Felix; Doroshenko, Victor; Camero-Arranz, Ascension

    2013-06-10

    We have analyzed three observations of the high-mass X-ray binary A 0535+26 performed by the Rossi X-Ray Timing Explorer (RXTE) three, five, and six months after the last outburst in 2011 February. We detect pulsations only in the second observation. The 3-20 keV spectra can be fit equally well with either an absorbed power law or absorbed thermal bremsstrahlung model. Reanalysis of two earlier RXTE observations made 4 yr after the 1994 outburst, original BeppoSAX observations 2 yr later, reanalysis of four EXOSAT observations made 2 yr after the last 1984 outburst, and a recent XMM-Newton observation in 2012 reveal a stacked, quiescent flux level decreasing from {approx}2 to <1 Multiplication-Sign 10{sup -11} erg cm{sup -2} s{sup -1} over 6.5 yr after outburst. The detection of pulsations during half of the quiescent observations would imply that accretion onto the magnetic poles of the neutron star continues despite the fact that the circumstellar disk may no longer be present. The accretion could come from material built up at the corotation radius or from an isotropic stellar wind.

  12. POLARIZATION MODULATION FROM LENSE–THIRRING PRECESSION IN X-RAY BINARIES

    SciTech Connect

    Ingram, Adam; Maccarone, Thomas J.; Poutanen, Juri; Krawczynski, Henric

    2015-07-01

    It has long been recognized that quasi-periodic oscillations (QPOs) in the X-ray light curves of accreting black hole and neutron star binaries have the potential to be powerful diagnostics of strong field gravity. However, this potential cannot be fulfilled without a working theoretical model, which has remained elusive. Perhaps, the most promising model associates the QPO with Lense–Thirring precession of the inner accretion flow, with the changes in viewing angle and Doppler boosting modulating the flux over the course of a precession cycle. Here, we consider the polarization signature of a precessing inner accretion flow. We use simple assumptions about the Comptonization process generating the emitted spectrum and take all relativistic effects into account, parallel transporting polarization vectors toward the observer along null geodesics in the Kerr metric. We find that both the degree of linear polarization and the polarization angle should be modulated on the QPO frequency. We calculate the predicted absolute rms variability amplitude of the polarization degree and angle for a specific model geometry. We find that it should be possible to detect these modulations for a reasonable fraction of parameter space with a future X-ray polarimeter such as NASA’s Polarization Spectroscopic Telescope Array (the satellite incarnation of the balloon experiment X-Calibur)

  13. The nature of very faint X-ray binaries: hints from light curves

    NASA Astrophysics Data System (ADS)

    Heinke, C. O.; Bahramian, A.; Degenaar, N.; Wijnands, R.

    2015-03-01

    Very faint X-ray binaries (VFXBs), defined as having peak luminosities LX of 1034-1036 erg s-1, have been uncovered in significant numbers, but remain poorly understood. We analyse three published outburst light curves of two transient VFXBs using the exponential and linear decay formalism of King & Ritter. The decay time-scales and brink luminosities suggest orbital periods of order 1 h. We review various estimates of VFXB properties, and compare these with suggested explanations of the nature of VFXBs. We suggest that: (1) VFXB outbursts showing linear decays might be explained as partial drainings of the disc of `normal' X-ray transients, and many VFXB outbursts may belong to this category; (2) VFXB outbursts showing exponential decays are best explained by old, short-period systems involving mass transfer from a low-mass white dwarf or brown dwarf; (3) persistent (or quasi-persistent) VFXBs, which maintain an LX of 1034-1035 erg s-1 for years, may be explained by magnetospheric choking of the accretion flow in a propeller effect, permitting a small portion of the flow to accrete on to the neutron star's surface. We thus predict that (quasi-) persistent VFXBs may also be transitional millisecond pulsars, turning on as millisecond radio pulsars when their LX drops below 1032 erg s-1.

  14. Orbital period change of the low-mass X-ray binary EXO 0748-676

    NASA Technical Reports Server (NTRS)

    Asai, Kazumi; Dotani, Tadayasu; Nagase, Fumiaki; Corbet, Robin H. D.; Shaham, Jacob

    1992-01-01

    The transient low-mass X-ray binary, EXO 0748-676, discovered with EXOSAT, is known to exhibit eclipses of a 492-s duration with a 3.82-hr period, intensity dips at pre-eclipse phases and type-I X-ray bursts. We observed this source with Ginga in 1989 March, 1990 December, 1991 January, and 1991 August and determined nine eclipse center times. Combining these eclipse center times with the previous result of the EXOSAT observations, we find that the orbital period of this source is not decaying monotonically, contrary to the previously reported suggestion. Instead, it shows a more complex behavior. A quadratic fit to the eclipse data yields a positive rate of change in orbital period with an approximate rate of 0.9 x 10 exp 7/yr, although the EXOSAT observations made in 1985 do not fit this trend. A sinusoidal function gives a better fit to the observed orbital period changes with a period of about 12 yr and an amplitude of about 44 lt-s, although the period is much longer than the observation interval of about 6.5 yr. Possible mechanisms for the orbital period change are discussed.

  15. Discovery of the Third Transient X-Ray Binary in the Galactic Globular Cluster Terzan 5

    NASA Astrophysics Data System (ADS)

    Bahramian, Arash; Heinke, Craig O.; Sivakoff, Gregory R.; Altamirano, Diego; Wijnands, Rudy; Homan, Jeroen; Linares, Manuel; Pooley, David; Degenaar, Nathalie; Gladstone, Jeanette C.

    2014-01-01

    We report and study the outburst of a new transient X-ray binary (XRB) in Terzan 5, the third detected in this globular cluster, Swift J174805.3-244637 or Terzan 5 X-3. We find clear spectral hardening in Swift/XRT data during the outburst rise to the hard state, thanks to our early coverage (starting at LX ~ 4 × 1034 erg s-1) of the outburst. This hardening appears to be due to the decline in relative strength of a soft thermal component from the surface of the neutron star (NS) during the rise. We identify a Type I X-ray burst in Swift/XRT data with a long (16 s) decay time, indicative of hydrogen burning on the surface of the NS. We use Swift/BAT, MAXI/GSC, Chandra/ACIS, and Swift/XRT data to study the spectral changes during the outburst, identifying a clear hard-to-soft state transition. We use a Chandra/ACIS observation during outburst to identify the transient's position. Seven archival Chandra/ACIS observations show evidence for variations in Terzan 5 X-3's nonthermal component but not the thermal component during quiescence. The inferred long-term time-averaged mass accretion rate, from the quiescent thermal luminosity, suggests that if this outburst is typical and only slow cooling processes are active in the NS core, such outbursts should recur every ~10 yr.

  16. A new deep, hard X-ray survey of M31: Identifying Black Holes and Neutron Stars in the X-ray Binary Population of our Nearest Neighbor

    NASA Astrophysics Data System (ADS)

    Wik, Daniel R.; Hornschemeier, Ann E.; Yukita, Mihoko; Ptak, Andrew; Lehmer, Bret; Maccarone, Thomas J.; Antoniou, Vallia; Zezas, Andreas; Harrison, Fiona; Stern, Daniel; Venters, Tonia M.; Williams, Benjamin F.; Eracleous, Michael; Plucinsky, Paul P.; Pooley, David A.

    2016-04-01

    X-ray binaries (XRBs) trace old and new stellar populations in galaxies, and thus star formation history and star formation rate. X-ray emission from XRBs may be responsible for significant amounts of heating of the early Intergalactic Medium (IGM) at Cosmic Dawn and may also play a significant role in reionization. Until recently, the hard emission from these populations could only be studied for XRBs in our own galaxy, where it is often difficult to measure accurate distances and thus luminosities. The launch of NuSTAR, the first focusing hard X-ray observatory, has allowed us to resolve the brightest XRBs (down to LX ~ few times 10^38 erg/s) in galaxies like NGC 253, M83, and M82 up to 4 Mpc away. To reach much lower X-ray luminosities that are more typical of XRBs in the Milky Way (Lx <~ 10^37 erg/s), we have observed M31 in 4 NuSTAR fields for more than 1 Ms total exposure, covering younger stellar population in a swath of the disk (within the footprint of the Panchromatic Hubble Andromeda Treasury (PHAT) Survey) and the older populations of the bulge. We detect 120 sources in the 4-25 keV band and over 40 hard band (12-25 keV) accreting black holes and neutron stars, distinguished by their spectral shape in this band. The luminosity function (LF) of the hard band detected sources are compared to Swift/BAT-derived LFs of the Milky Way population, which reveals an excess of luminous sources in M31 when correcting for star formation rate and stellar mass. We also discuss implications for this updated understanding of XRB populations on early-Universe measurements in, e.g., the 7 Ms Chandra Deep Field survey.

  17. GLOBULAR CLUSTER FORMATION EFFICIENCIES FROM BLACK HOLE X-RAY BINARY FEEDBACK

    SciTech Connect

    Justham, Stephen; Peng, Eric W.; Schawinski, Kevin

    2015-08-10

    We investigate a scenario in which feedback from black hole X-ray binaries (BHXBs) sometimes begins inside young star clusters before strong supernova (SN) feedback. Those BHXBs could reduce the gas fraction inside embedded young clusters while maintaining virial equilibrium, which may help globular clusters (GCs) to stay bound when SN-driven gas ejection subsequently occurs. Adopting a simple toy model with parameters guided by BHXB population models, we produce GC formation efficiencies consistent with empirically inferred values. The metallicity dependence of BHXB formation could naturally explain why GC formation efficiency is higher at lower metallicity. For reasonable assumptions about that metallicity dependence, our toy model can produce a GC metallicity bimodality in some galaxies without a bimodality in the field-star metallicity distribution.

  18. Evolution of the Spin Periods of Neutron Stars in Low-mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Xu, X. T.; Zhu, Z. L.

    2016-11-01

    We present numerical analysis of the spin evolution of the neutron stars in low-mass X-ray binaries, trying to explain the discrepancy in the spin period distribution between observations of millisecond pulsars and theoretical results. In our calculations, we take account of possible effect of radiation pressure, and irradiation-induced instability on the structure of the disk, and the evolution of the mass transfer rate, respectively. We report the following results: (1) Radiation pressure leads to a slight increase of the spin periods, and irradiation-induced mass transfer cycles can shorten the spin-down phase of evolution. (2) The calculated results in the model combining radiation pressure and irradiation-induced mass transfer cycles show that accretion is strongly limited by radiation pressure in high mass transfer phase. (3) The accreted mass and the critical fastness parameter can affect the number of systems in equilibrium state.

  19. EVOLUTION OF TRANSIENT LOW-MASS X-RAY BINARIES TO REDBACK MILLISECOND PULSARS

    SciTech Connect

    Jia, Kun; Li, Xiang-Dong

    2015-11-20

    Redback millisecond pulsars (MSPs; hereafter redbacks) are a subpopulation of eclipsing MSPs in close binaries. The formation processes of these systems are not clear. The three pulsars showing transitions between rotation- and accretion-powered states belong to both redbacks and transient low-mass X-ray binaries (LMXBs), suggesting a possible evolutionary link between them. Through binary evolution calculations, we show that the accretion disks in almost all LMXBs are subject to the thermal-viscous instability during certain evolutionary stages, and the parameter space for the disk instability covers the distribution of known redbacks in the orbital period—companion mass plane. We accordingly suggest that the abrupt reduction of the mass accretion rate during quiescence of transient LMXBs provides a plausible way to switch on the pulsar activity, leading to the formation of redbacks, if the neutron star has been spun up to be an energetic MSP. We investigate the evolution of redbacks, taking into account the evaporation feedback, and discuss its possible influence on the formation of black widow MSPs.

  20. ON THE RARITY OF X-RAY BINARIES WITH NAKED HELIUM DONORS

    SciTech Connect

    Linden, T.; Valsecchi, F.; Kalogera, V.

    2012-04-01

    The paucity of known high-mass X-ray binaries (HMXBs) with naked He donor stars (hereafter He star) in the Galaxy has been noted over the years as a surprising fact, given the significant number of Galactic HMXBs containing H-rich donors, which are expected to be their progenitors. This contrast has further sharpened in light of recent observations uncovering a preponderance of HMXBs hosting loosely bound Be donors orbiting neutron stars (NSs), which would be expected to naturally evolve into He-HMXBs through dynamical mass transfer onto the NS and a common-envelope (CE) phase. Hence, reconciling the large population of Be-HMXBs with the observation of only one He-HMXB can help constrain the dynamics of CE physics. Here, we use detailed stellar structure and evolution models and show that binary mergers of HMXBs during CE events must be common in order to resolve the tension between these observed populations. We find that, quantitatively, this scenario remains consistent with the typically adopted energy parameterization of CE evolution, yielding expected populations which are not at odds with current observations. However, future observations which better constrain the underlying population of loosely bound O/B-NS binaries are likely to place significant constraints on the efficiency of CE ejection.

  1. THE ORIGIN OF BLACK HOLE SPIN IN GALACTIC LOW-MASS X-RAY BINARIES

    SciTech Connect

    Fragos, T.; McClintock, J. E.

    2015-02-10

    Galactic field black hole (BH) low-mass X-ray binaries (LMXBs) are believed to form in situ via the evolution of isolated binaries. In the standard formation channel, these systems survived a common envelope phase, after which the remaining helium core of the primary star and the subsequently formed BH are not expected to be highly spinning. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters. We propose here that the BH spin in LMXBs is acquired through accretion onto the BH after its formation. In order to test this hypothesis, we calculated extensive grids of detailed binary mass-transfer sequences. For each sequence, we examined whether, at any point in time, the calculated binary properties are in agreement with their observationally inferred counterparts of 16 Galactic LMXBs. The ''successful'' sequences give estimates of the mass that the BH has accreted since the onset of Roche-Lobe overflow. We find that in all Galactic LMXBs with measured BH spin, the origin of the spin can be accounted for by the accreted matter, and we make predictions about the maximum BH spin in LMXBs where no measurement is yet available. Furthermore, we derive limits on the maximum spin that any BH can have depending on current properties of the binary it resides in. Finally we discuss the implication that our findings have on the BH birth-mass distribution, which is shifted by ∼1.5 M {sub ☉} toward lower masses, compared to the currently observed one.

  2. The origin of Black-Hole Spin in Galactic Low-Mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Fragos, Tassos; McClintock, Jeffrey

    2015-08-01

    Galactic field low-mass X-ray binaries (LMXBs), like the ones for which black hole (BH) spin measurements are available, are believed to form in situ via the evolution of isolated binaries. In the standard formation channel, these systems survived a common envelope phase, after which the remaining helium core of the primary star and the subsequently formed BH are not expected to be highly spinning. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters from a*~0 to a*1. In this talk I propose that the BH spin in LMXBs is acquired through accretion onto the BH during its long stable accretion phase. In order to test this hypothesis, I calculated extensive grids of binary evolutionary sequences in which a BH accretes matter from a close companion. For each evolutionary sequence, I examined whether, at any point in time, the calculated binary properties are in agreement with their observationally inferred counterparts of observed Galactic LMXBs with BH spin measurements. Mass-transfer sequences that simultaneously satisfy all observational constraints represent possible progenitors of the considered LMXBs and thus give estimates of the amount of matter that the BH has accreted since the onset of Roche-Lobe overflow. I find that in all Galactic LMXBs with measured BH spin, the origin of the spin can be accounted by the accreted matter. Furthermore, based on this hypothesis, I derive limits on the maximum spin that a BH can have depending on the orbital period of the binary it resides in, and give predictions on the maximum possible BH spin of Galactic LMXBs where a BH spin measurement is not yet available. Finally I will discuss the implication that our findings have on the birth black hole mass distribution.

  3. X-ray Studies of the Black Hole Binary Cygnus X-1 with Suzaku

    NASA Astrophysics Data System (ADS)

    Yamada, Shin'ya

    2011-03-01

    In order to study X-ray properties of black hole binaries in so-called Low/Hard state, we analyzed 0.5--300 keV data of Cyg X-1, taken with the X-ray Imaging Spectrometer and the Hard X-ray Detector onboard the X-ray satellite Suzaku. The data were acquired on 25 occasions from 2005 to 2009, with a total exposure of ~450 ks. The source was in the Low/Hard state throughout, and the 0.5-300 keV luminosity changed by a factor of 4, corresponding to 2-10% of the Eddington limit for a 10 Mo black hole. Among the 25 data sets, the first one was already analyzed by Makishima et al. (2008), who successfully reproduced the wide-band spectrum by a linear combination of an emission from a standard accretion disk, soft and hard Comptonization continua, and reprocessed features. Given this, we analyzed the 25 data sets for intensity-related spectral changes, on three different time scales using different analysis methods. One is the source behavior on time scales of days to months, studied via direct comparison among the 25 spectra which are averaged over individual observations. Another is spectral changes on time scales of 1-2 seconds, revealed through ``intensity-sorted spectroscopy''. The other is spectral changes on time scales down to ~0.1 seconds, conducted using ``shot analysis" technique which was originally developed by Negoro et al. (1997) with Ginga. These studies partially incorporated spectral fitting in terms of a thermal Comptonization model. We payed great attention to instrumental problems caused by the source brightness, and occasional ``dipping" episodes which affects the Cyg X-1 spectrum at low energies. The shot analysis incorporated a small fraction of XIS data that were taken in the P-sum mode with a time resolution of 7.8 msec. Through these consistent analyses of all the 25 data sets, we found that a significant soft X-ray excess develops as the source gets brighter. Comparing results from the different time scales, the soft excess was further

  4. Radiative Signatures of Reconnection in X-ray Binary Spectral States

    NASA Astrophysics Data System (ADS)

    Uzdensky, Dmitri

    Accreting black holes (BHs) in Galactic X-ray Binary (XRB) systems represent some of the main targets of space-based high-energy observatories such as NASA s RXTE, Chandra, and NuSTAR, as well as the international observatories XMM Newton, INTEGRAL, Suzaku (Astro-E), and Astro-H. The overall radiative energy output (mostly X-rays) is ultimately powered by the conversion of the gravitational potential energy of the matter falling onto a black hole and forming an accretion disk or a hot accretion flow around it. Observationally, these systems are found to cycle between a few discrete spectral states, characterized by different overall X-ray power and spectral hardness: (1) the bright thermal high-soft state, dominated by a soft (1 keV) thermal component attributed to a thin dense accretion disk with a relatively weak corona producing a power-law tail emission to at least 1 MeV; (2) the low-hard state, showing no signs of a thin accretion disk and dominated by a single hard (with index ~ -1.7) power law truncating at about 100 keV; and (3) the bright Steep Power Law state with both a standard thin disk and a powerful coronal power-law (with index about -2.5) emission extending to at least 1 MeV. Explaining the key features of these nonthermal spectra, i.e., their power law indices and high-energy cutoffs, is one of the outstanding problems in high-energy astrophysics. The hard (10keV 1MeV) X-ray emission in these states is believed to be produced by inverse-Compton scattering in relativistically-hot gas, presumably heated by magnetic reconnection processes, and forming either an accretion disk corona or the hot accretion flow itself. Since the radiative cooling time of the energetic electrons in the intense radiation fields found in these systems is very short, the observed non-thermal hard X-ray spectra should directly reflect the instantaneous energy spectra of the electrons accelerated in reconnection events. Recent advances in kinetic simulations of reconnection

  5. Timing and Spectral Studies of the Peculiar X-ray Binary Circinus X-1

    SciTech Connect

    Saz Parkinson, Pablo M.

    2003-08-26

    Circinus X-1 (Cir X-1) is an X-ray binary displaying an array of phenomena which makes it unique in our Galaxy. Despite several decades of observation, controversy surrounds even the most basic facts about this system. It is generally classified as a Neutron Star (NS) Low Mass X-ray Binary (LMXB),though this classification is based primarily on the observation of Type I X-ray Bursts by EXOSAT in 1985. It is believed to be in a very eccentric {approx} 16.5 day orbit, displaying periodic outbursts in the radio and other frequency bands (including optical and IR) which reinforce the notion that this is in fact the orbital period. Cir X-1 lies in the plane of the Galaxy, where optical identification of the companion is made difficult due to dust obscuration. The companion is thought to be a low mass star, though a high mass companion has not currently been ruled out. In this work, the author analyzes recent observations of Cir X-1 made with the Unconventional Stellar Aspect (USA) experiment, as well as archival observations of Cir X-1 made by a variety of instruments, from as early as 1969. The fast (< 1 s) timing properties of Cir X-1 are studied by performing FFT analyses of the USA data. Quasi-Periodic Oscillations (QPOs) in the 1-50 Hz range are found and discussed in the context of recent correlations which question the leading models invoked for their generation. The energy dependence of the QPOs (rms increasing with energy) argues against them being generated in the disk and favors models in which the QPOs are related to a higher energy Comptonizing component. The power spectrum of Cir X-1 in its soft state is compared to that of Cygnus X-1 (Cyg X-1), the prototypical black hole candidate. Using scaling arguments the author argues that the mass of Cir X-1 could exceed significantly the canonical 1.4 M{circle_dot} mass of a neutron star, possibly partly explaining why this object appears so different to other neutron stars. The spectral evolution of Cir X-1 is

  6. Contrasting Behaviour from Two Be/X-ray Binary Pulsars: Insights into Differing Neutron Star Accretion Modes

    NASA Technical Reports Server (NTRS)

    Townsend, L. J.; Drave, S. P.; Hill, A. B.; Coe, M. J.; Corbet, R. H. D.; Bird, A. J.

    2013-01-01

    In this paper we present the identification of two periodic X-ray signals coming from the direction of the Small Magellanic Cloud (SMC). On detection with the Rossi X-ray Timing Explorer (RXTE), the 175.4 s and 85.4 s pulsations were considered to originate from new Be/X-ray binary (BeXRB) pulsars with unknown locations. Using rapid follow-up INTEGRAL and XMM-Newton observations, we show the first pulsar (designated SXP175) to be coincident with a candidate high-mass X-ray binary (HMXB) in the northern bar region of the SMC undergoing a small Type II outburst. The orbital period (87d) and spectral class (B0-B0.5IIIe) of this system are determined and presented here for the first time. The second pulsar is shown not to be new at all, but is consistent with being SXP91.1 - a pulsar discovered at the very beginning of the 13 year long RXTE key monitoring programme of the SMC. Whilst it is theoretically possible for accreting neutron stars to change spin period so dramatically over such a short time, the X-ray and optical data available for this source suggest this spin-up is continuous during long phases of X-ray quiescence, where accretion driven spin-up of the neutron star should be minimal.

  7. Observational Evidence For The Cause Of The `Parallel Track' Phenomenon And Hysteresis Of Spectral Transitions In X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Yu, Wenfei

    2010-03-01

    RXTE observations of neutron star LMXBs have shown the same kHz QPO frequency or the same X-ray color occurs at different X-ray fluxes in a single source, forming the so-called `parallel track' phenomenon. Hysteresis effect of spectral transitions, which is usually seen in black hole or neutron star soft X-ray transients, corresponds to the special cases of the phenomenon when the X-ray colors transit between two main spectral branches. Our systematic studies of the spectral state transitions seen in bright X-ray binaries with the RXTE/ASM and the Swift/BAT in the past 4-5 years indicates that the rate-of-change of the mass accretion rate dominates over the mass accretion rate itself in causing spectral state transitions, implying the rate-of-change of the mass accretion rate, an indicator of the non-stationary accretion in X-ray binaries, is the cause of both phenomena. Spectral and timing evidence will be provided in the presentation.

  8. On binary driven hypernovae and their nested late X-ray emission

    NASA Astrophysics Data System (ADS)

    Muccino, Marco; Ruffini, Remo; Bianco, Carlo Luciano; Enderli, Maxime; Kovacevic, Milos; Izzo, Luca; Penacchioni, Ana Virginia; Pisani, Giovanni Battista; Rueda, Jorge A.; Wang, Yu

    2015-07-01

    The induced gravitational collapse (IGC) paradigm addresses energetic (1052-1054 erg), long gamma-ray bursts (GRBs) associated to supernovae (SNe) and proposes as their progenitors tight binary systems composed of an evolved FeCO core and a companion neutron star (NS). Their emission is characterized by four specific episodes: Episode 1, corresponding to the on-set of the FeCO SN explosion and the accretion of the ejecta onto the companion NS; Episode 2, related the collapse of the companionNS to a black hole (BH) and to the emission of a long GRB; Episode 3, observed in X-rays and characterized by a steep decay, a plateau phase and a late power-law decay; Episode 4, corresponding to the optical SN emission due to the 56Ni decay. We focus on Episode 3 and we show that, from the thermal component observed during the steep decay of the prototype GRB 090618, the emission region has a typical dimension of ~1013 cm, which is inconsistent with the typical size of the emitting region of GRBs, e.g., ~1016 cm. We propose, therefore, that the X-ray afterglow emission originates from a spherically symmetric SN ejecta expanding at G ˜ 2 or, possibly, from the accretion onto the newly formed black hole, and we name these systems "binary driven hypernovae" (BdHNe). This interpretation is alternative to the traditional afterglow model based on the GRB synchrotron emission from a collimated jet outflow, expanding at ultra-relativistic Lorentz factor of G ~ 102-103 and originating from the collapse of a single object. We show then that the rest-frame energy band 0.3-10 keV X-ray luminosities of three selected BdHNe, GRB 060729, GRB 061121, and GRB 130427A, evidence a precisely constrained "nested" structure and satisfy precise scaling laws between the average prompt luminosity, < Liso>, and the luminosity at the end of the plateau, La, as functions of the time at the end of the plateau. All these features extend the applicability of the "cosmic candle" nature of Episode 3. The

  9. Chandra X-Ray Observatory Image of a Massive Star Explosion

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Chandra X-Ray Observatory has captured this spectacular image of G292.0+1.8, a young, oxygen-rich supernova remnant with a pulsar at its center surrounded by outflowing material. This image shows a rapidly expanding shell of gas that is 36 light-years across and contains large amounts of elements such as oxygen, neon, magnesium, silicon and sulfur. Embedded in this cloud of multimillion-degree gas is a key piece of evidence linking neutron stars and supernovae produced by the collapse of massive stars. With an age estimated at 1,600 years, G292.0+1.8 is one of three known oxygen-rich supernovae in our galaxy. These supernovae are of great interest to astronomers because they are one of the primary sources of the heavy elements necessary to form planets and people. Scattered through the image are bluish knots of emissions containing material that is highly enriched in newly created oxygen, neon, and magnesium produced deep within the original star and ejected by the supernova explosion.

  10. X-ray emission and the incidence of magnetic fields in the massive stars of the Orion Nebula Cluster

    NASA Astrophysics Data System (ADS)

    Petit, V.; Wade, G. A.; Montmerle, T.; Drissen, L.; Grosso, N.; Menard, F.

    Magnetic fields have been frequently invoked as a likely source of variability and confinement of the winds of massive stars. To date, the only magnetic field detected in O-type stars are those of θ1 Ori C (HD 37022; Donati et al. 2002), the brightest and most massive member of the Orion Nebula Cluster (ONC), and HD 191612 (Donati et al. 2006). Notably, θ1 Ori C is an intense X-ray emitter, and the source of these X-rays is thought to be strong shocks occurring in its magnetically-confined wind (Babel & Montmerle 1997a, Donati et al. 2002). Recently, Stelzer et al. (2005) have found significant X-ray emission from all massive stars in the ONC. Periodic rotational modulation in X-rays and other indicators suggested that θ1 Ori C may be but one of many magnetic B- and O-type stars in this star-forming region. In 2005B we carried out sensitive ESPaDOnS observations to search for direct evidence of such fields, detecting unambiguous Zeeman signatures in two objects.

  11. CXOGBS J173620.2-293338: A candidate symbiotic X-ray binary associated with a bulge carbon star

    SciTech Connect

    Hynes, Robert I.; Britt, C. T.; Johnson, C. B.; Torres, M. A. P.; Jonker, P. G.; Heinke, C. O.; Maccarone, T. J.; Mikles, V. J.; Knigge, C.; Greiss, S.; Steeghs, D.; Nelemans, G.; Bandyopadhyay, R. M.

    2014-01-01

    The Galactic Bulge Survey (GBS) is a wide but shallow X-ray survey of regions above and below the Plane in the Galactic Bulge. It was performed using the Chandra X-ray Observatory's ACIS camera. The survey is primarily designed to find and classify low luminosity X-ray binaries. The combination of the X-ray depth of the survey and the accessibility of optical and infrared counterparts makes this survey ideally suited to identification of new symbiotic X-ray binaries (SyXBs) in the Bulge. We consider the specific case of the X-ray source CXOGBS J173620.2-293338. It is coincident to within 1 arcsec with a very red star, showing a carbon star spectrum and irregular variability in the Optical Gravitational Lensing Experiment data. We classify the star as a late C-R type carbon star based on its spectral features, photometric properties, and variability characteristics, although a low-luminosity C-N type cannot be ruled out. The brightness of the star implies it is located in the Bulge, and its photometric properties are overall consistent with the Bulge carbon star population. Given the rarity of carbon stars in the Bulge, we estimate the probability of such a close chance alignment of any GBS source with a carbon star to be ≲ 10{sup –3}, suggesting that this is likely to be a real match. If the X-ray source is indeed associated with the carbon star, then the X-ray luminosity is around 9 × 10{sup 32} erg s{sup –1}. Its characteristics are consistent with a low luminosity SyXB, or possibly a low accretion rate white dwarf symbiotic.

  12. Detection of the first infra-red quasi-periodic oscillation in a black hole X-ray binary

    NASA Astrophysics Data System (ADS)

    Kalamkar, M.; Casella, P.; Uttley, P.; O'Brien, K.; Russell, D.; Maccarone, T.; van der Klis, M.; Vincentelli, F.

    2016-08-01

    We present the analysis of fast variability of Very Large Telescope/ISAAC (Infrared Spectrometer And Array Camera) (infra-red), XMM-Newton/OM (optical) and EPIC-pn (X-ray), and RXTE/PCA (X-ray) observations of the black hole X-ray binary GX 339-4 in a rising hard state of its outburst in 2010. We report the first detection of a quasi-periodic oscillation (QPO) in the infra-red band (IR) of a black hole X-ray binary. The QPO is detected at 0.08 Hz in the IR as well as two optical bands (U and V). Interestingly, these QPOs are at half the X-ray QPO frequency at 0.16 Hz, which is classified as the type-C QPO; a weak sub-harmonic close to the IR and optical QPO frequency is also detected in X-rays. The band-limited sub-second time-scale variability is strongly correlated in IR/X-ray bands, with X-rays leading the IR by over 120 ms. This short time delay, shape of the cross-correlation function and spectral energy distribution strongly indicate that this band-limited variable IR emission is the synchrotron emission from the jet. A jet origin for the IR QPO is strongly favoured, but cannot be definitively established with the current data. The spectral energy distribution indicates a thermal disc origin for the bulk of the optical emission, but the origin of the optical QPO is unclear. We discuss our findings in the context of the existing models proposed to explain the origin of variability.

  13. A numerical investigation of wind accretion in persistent Supergiant X-ray Binaries I - Structure of the flow at the orbital scale

    NASA Astrophysics Data System (ADS)

    El Mellah, I.; Casse, F.

    2017-01-01

    Classical Supergiant X-ray Binaries host a neutron star orbiting a supergiant OB star and display persistent X-ray luminosities of 1035 to 1037 erg· s-1. The stellar wind from the massive companion is believed to be the main source of matter accreted by the compact object. With this first paper, we introduce a ballistic model to evaluate the influence of the orbital effects on the structure of the accelerating winds which participate to the accretion process. Thanks to the parametrization we retained and the numerical pipeline we designed, we can investigate the supersonic flow and the subsequent observables as a function of a reduced set of characteristic numbers and scales. We show that the shape of the permanent flow is entirely determined by the mass ratio, the filling factor, the Eddington factor and the α-force multiplier which drives the stellar wind acceleration. Provided scales such as the orbital period are known, we can trace back the observables to evaluate the mass accretion rates, the accretion mechanism, the shearing of the inflow and the stellar parameters. We discuss the likelihood of wind-formed accretion discs around the accretors in each case and confront our model to three persistent Supergiant X-ray Binaries (Vela X-1, IGR J18027-2016, XTE J1855-026).

  14. A MODEL FOR THE CORRELATION OF HARD X-RAY INDEX WITH EDDINGTON RATIO IN BLACK HOLE X-RAY BINARIES

    SciTech Connect

    Qiao, Erlin; Liu, B. F.

    2013-02-10

    Observations show that there is a positive correlation between the Eddington ratio {lambda} and hard X-ray index {Gamma} for {lambda} {approx}> 0.01, and there is an anti-correlation between {lambda} and {Gamma} for {lambda} {approx}< 0.01 in black hole X-ray binaries (with {lambda} = L {sub bol}/L {sub Edd}). In this work, we theoretically investigate the correlation between {Gamma} and {lambda} within the framework of a disk-corona model. We improve the model by taking into account all cooling processes, including synchrotron and self-Compton radiations in the corona, Comptonization of the soft photons from the underlying accretion disk, and the bremsstrahlung radiations. Presuming that the coronal flow above the disk can reach up to the 0.1 Eddington rate at the outer region, we calculate the structure of the two-phase accretion flows and the emergent spectra for accretion rates from 0.003 to 0.1. We find that at accretion rates larger than bsim0.01 Eddington rate, a fraction of coronal gas condenses into the disk and an inner disk can be sustained by condensation. In this case, the X-ray emission is dominated by the scattering of the soft photon from the underlying disk in the corona. The emission from the inner disk and corona can produce the positive correlation between {lambda} and {Gamma}. While at accretion rates lower than bsim0.01 Eddington accretion rate, the inner disk vanishes completely by evaporation, and the accretion is dominated by advection-dominated accretion flows (ADAFs), in which the X-ray emission is produced by the Comptonization of the synchrotron and bremsstrahlung photons of ADAF itself. The emission from ADAFs can produce the anti-correlation between {lambda} and {Gamma}. We show that our model can roughly explain the observed evolution of {Gamma}{sub 3-25keV} with L {sub 0.5-25keV}/L {sub Edd} for the black hole X-ray transient H1743-322 in the decay of 2003 from the thermal-dominated state to low/hard state.

  15. Heating the intergalactic medium by X-rays from population III binaries in high-redshift galaxies

    SciTech Connect

    Xu, Hao; Norman, Michael L.; Ahn, Kyungjin; Wise, John H.; O'Shea, Brian W. E-mail: mlnorman@ucsd.edu E-mail: jwise@gatech.edu

    2014-08-20

    Due to their long mean free path, X-rays are expected to have an important impact on cosmic reionization by heating and ionizing the intergalactic medium (IGM) on large scales, especially after simulations have suggested that Population III (Pop III) stars may form in pairs at redshifts as high as 20-30. We use the Pop III distribution and evolution from a self-consistent cosmological radiation hydrodynamic simulation of the formation of the first galaxies and a simple Pop III X-ray binary model to estimate their X-ray output in a high-density region larger than 100 comoving (Mpc){sup 3}. We then combine three different methods—ray tracing, a one-zone model, and X-ray background modeling—to investigate the X-ray propagation, intensity distribution, and long-term effects on the IGM thermal and ionization state. The efficiency and morphology of photoheating and photoionization are dependent on the photon energies. The sub-kiloelectronvolt X-rays only impact the IGM near the sources, while the kiloelectronvolt photons contribute significantly to the X-ray background and heat and ionize the IGM smoothly. The X-rays just below 1 keV are most efficient in heating and ionizing the IGM. We find that the IGM might be heated to over 100 K by z = 10 and the high-density source region might reach 10{sup 4} K, limited by atomic hydrogen cooling. This may be important for predicting the 21 cm neutral hydrogen signals. On the other hand, the free electrons from X-ray ionizations are not enough to contribute significantly to the optical depth of the cosmic microwave background to the Thomson scattering.

  16. Heating the Intergalactic Medium by X-Rays from Population III Binaries in High-redshift Galaxies

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Ahn, Kyungjin; Wise, John H.; Norman, Michael L.; O'Shea, Brian W.

    2014-08-01

    Due to their long mean free path, X-rays are expected to have an important impact on cosmic reionization by heating and ionizing the intergalactic medium (IGM) on large scales, especially after simulations have suggested that Population III (Pop III) stars may form in pairs at redshifts as high as 20-30. We use the Pop III distribution and evolution from a self-consistent cosmological radiation hydrodynamic simulation of the formation of the first galaxies and a simple Pop III X-ray binary model to estimate their X-ray output in a high-density region larger than 100 comoving (Mpc)3. We then combine three different methods—ray tracing, a one-zone model, and X-ray background modeling—to investigate the X-ray propagation, intensity distribution, and long-term effects on the IGM thermal and ionization state. The efficiency and morphology of photoheating and photoionization are dependent on the photon energies. The sub-kiloelectronvolt X-rays only impact the IGM near the sources, while the kiloelectronvolt photons contribute significantly to the X-ray background and heat and ionize the IGM smoothly. The X-rays just below 1 keV are most efficient in heating and ionizing the IGM. We find that the IGM might be heated to over 100 K by z = 10 and the high-density source region might reach 104 K, limited by atomic hydrogen cooling. This may be important for predicting the 21 cm neutral hydrogen signals. On the other hand, the free electrons from X-ray ionizations are not enough to contribute significantly to the optical depth of the cosmic microwave background to the Thomson scattering.

  17. Finding a 24 Day Orbital Period for the X-Ray Binary 1A 1118-616

    NASA Technical Reports Server (NTRS)

    Staubert, R.; Pottschmidt, K.; Doroshenko, V.; Wilms, J.; Suchy, S.; Rothschild, R.; Santangelo, A.

    2010-01-01

    We report the first determination of the binary period and the orbital ephemeris of the Be X-ray binary containing the pulsar IA 1118-616 (35 years after the discovery of the source). The orbital period is found to be P(sub orb) = 24.0+/-0.4 days. The source was observed by RXTE during its last big X-ray outburst in January 2009, peaking at MJD 54845.4. This outburst was sampled by taking short observations every few days, covering an elapsed time comparable to the orbital period. Using the phase connection technique, pulse arrival time delays could be measured and an orbital solution determined. The data are consistent with a circular orbit, the time of 90 degrees longitude was found to be T,/2 = MJD 54845.37(10), coincident with the peak X-ray flux.

  18. High Energy Observations of X-Ray Binaries and Gamma-Ray Blazars

    NASA Technical Reports Server (NTRS)

    Vestrand, W. Thomas

    1999-01-01

    The report discusses the CGRO observation of X-ray binary systems and studies of gamma-ray blasars. Numerous authors have suggested mechanisms for particle acceleration within X-Ray Binary (XRB) systems. Among the acceleration mechanisms that have been applied are pulsar acceleration, shock acceleration at an accretion shock front, shock acceleration at a pulsar wind termination shock, plasma turbulence excited by the accretion flow, and a number of electrodynamic mechanisms. There are therefore many mechanisms which are capable of generating very energetic particles in the XRB environment. If the reports of TeV/PeV gamma-ray generation in XRBs are correct, then one can show that the accelerated particles must be hadrons and that the most likely gamma-ray production mechanism is the decay of collisionally-produced (or photoproduced) neutral pions. At these ultra-high energies, the emission is so strongly beamed that the target conditions are constrained by the requirement that the column depth be large enough to efficiently generate gamma-rays, but not so large that the gamma-rays are absorbed. These constraints naturally lead to models that explain the periodic, narrow duty-cycle pulses observed at TeV/PeV energies as arising from interactions with, either, the atmosphere of the binary companion, an accretion column, or an accretion disk. The production of these TeV/PeV gamma-rays by the decay of pions from "leading isobars" must also be accompanied by a more isotropic emission component in the EGRET energy band from the decay of slower pions (i.e. the "pionization" component). Since the attenuation of 35 MeV-1 GeV photons by photon-photon pair production is not likely to be significant in most XRBs, the TeV/PeV reports therefore strongly suggest sporadic emission in the EGRET energy band. One of the key unresolved issues for understanding AGN is the relationship between XBLs and RBLs.To test the "reunification" hypothesis, authors conducted a multiwavelength

  19. High energy neutrino absorption and its effects on stars in close X-ray binaries

    NASA Technical Reports Server (NTRS)

    Gaisser, T. K.; Stecker, F. W.

    1986-01-01

    The physics and astrophysics of high energy neutrino production and interactions in close X-ray binary systems are studied. These studies were stimulated by recent observations of ultrahigh energy gamma-rays and possibly other ultrahigh energy particles coming from the directions of Cygnus X-3 and other binary systems and possessing the periodicity characteristics of these systems. Systems in which a compact object, such as a neutron star, is a strong source of high energy particles which, in turn, produce photons, neutronos and other secondary particles by interactions in the atmosphere of the companion star were considered. The highest energy neutrinos are absorbed deep in the companion and the associated energy deposition may be large enough to effect its structure or lead to its ultimate disruption. This neutrino heating was evaluated, starting with a detailed numerical calculation of the hadronic cascade induced in the atmosphere of the companion star. For some theoretical models, the resulting energy deposition from neutrino absorption may be so great as to disrupt the companion star over an astronomically small timescale of the order of 10,000 years. Even if the energy deposition is smaller, it may still be high enough to alter the system substantially, perhaps leading to quenching of high energy signals from the source. Given the cosmic ray luminosities required to produce the observed gamma rays from cygnus X-3 and LMX X-4, such a situation may occur in these sources.

  20. A Chandra X-Ray Census of the Interacting Binaries in Old Open Clusters—Collinder 261

    NASA Astrophysics Data System (ADS)

    Vats, Smriti; van den Berg, Maureen

    2017-03-01

    We present the first X-ray study of Collinder 261 (Cr 261), which at an age of 7 Gyr is one of the oldest open clusters known in the Galaxy. Our observation with the Chandra X-Ray Observatory is aimed at uncovering the close interacting binaries in Cr 261, and reaches a limiting X-ray luminosity of {L}X≈ 4× {10}29 {erg} {{{s}}}-1 (0.3–7 keV) for stars in the cluster. We detect 107 sources within the cluster half-mass radius r h , and we estimate that among the sources with {L}X≳ {10}30 {erg} {{{s}}}-1, ∼26 are associated with the cluster. We identify a mix of active binaries and candidate active binaries, candidate cataclysmic variables, and stars that have “straggled” from the main locus of Cr 261 in the color–magnitude diagram. Based on a deep optical source catalog of the field, we estimate that Cr 261 has an approximate mass of 6500 M ⊙, roughly the same as the old open cluster NGC 6791. The X-ray emissivity of Cr 261 is similar to that of other old open clusters, supporting the trend that they are more luminous in X-rays per unit mass than old populations of higher (globular clusters) and lower (the local neighborhood) stellar density. This implies that the dynamical destruction of binaries in the densest environments is not solely responsible for the observed differences in X-ray emissivity.

  1. THE INTEGRATED DIFFUSE X-RAY EMISSION OF THE CARINA NEBULA COMPARED TO OTHER MASSIVE STAR-FORMING REGIONS

    SciTech Connect

    Townsley, Leisa K.; Broos, Patrick S.; Chu, You-Hua; Gruendl, Robert A.; Oey, M. S.; Pittard, Julian M.

    2011-05-01

    The Chandra Carina Complex Project (CCCP) has shown that the Carina Nebula displays bright, spatially-complex soft diffuse X-ray emission. Here, we 'sum up' the CCCP diffuse emission work by comparing the global morphology and spectrum of Carina's diffuse X-ray emission to other famous sites of massive star formation with pronounced diffuse X-ray emission: M17, NGC 3576, NGC 3603, and 30 Doradus. All spectral models require at least two diffuse thermal plasma components to achieve adequate spectral fits, a softer component with kT = 0.2-0.6 keV and a harder component with kT = 0.5-0.9 keV. In several cases these hot plasmas appear to be in a state of non-equilibrium ionization that may indicate recent and current strong shocks. A cavity north of the embedded giant H II region NGC 3576 is the only region studied here that exhibits hard diffuse X-ray emission; this emission appears to be nonthermal and is likely due to a recent cavity supernova, as evidenced by a previously-known pulsar and a newly-discovered pulsar wind nebula also seen in this cavity. All of these targets exhibit X-ray emission lines that are not well modeled by variable-abundance thermal plasmas and that might be attributed to charge exchange at the shock between the hot, tenuous, X-ray-emitting plasma and cold, dense molecular material; this is likely evidence for dust destruction at the many hot/cold interfaces that characterize massive star-forming regions.

  2. Optical activity of the high-mass X-ray binary SAX J2103.5+4545.

    NASA Astrophysics Data System (ADS)

    Grishina, T. S.; Larionova, E. G.; Savchenko, S. S.; Larionov, V. M.

    2017-03-01

    We report on the renewed optical activity of the high-mass X-ray binary system SAX J2103.5+4545. The source is monitored with the 0.4-m LX-200 (St.Petersburg, Russia) and 0.7-m AZT-8 (CrAO, Russia) telescopes.

  3. The neutron-star low-mass X-ray binary H 1658-298 back in quiescence

    NASA Astrophysics Data System (ADS)

    Parikh, Aastha; Wijnands, Rudy; Bahramian, Arash; Degenaar, Nathalie; Heinke, Craig

    2017-03-01

    The transient and eclipsing neutron-star low-mass X-ray binary H 1658-298 began its most recent outburst in August 2015 as determined using MAXI (ATel #7943) and we continued to monitor the outburst using Swift/XRT (e.g., ATel #7957, #8046).

  4. CORONAE AND WINDS FROM IRRADIATED DISKS IN X-RAY BINARIES

    SciTech Connect

    Higginbottom, Nick; Proga, Daniel E-mail: dproga@physics.unlv.edu

    2015-07-01

    X-ray and UV line emission in X-ray binaries (XRBs) can be accounted for by a hot corona. Such a corona forms through irradiation of the outer disk by radiation produced in the inner accretion flow. The same irradiation can produce a strong outflow from the disk at sufficiently large radii. Outflowing gas has been recently detected in several XRBs via blueshifted absorption lines. However, the causal connection between winds produced by irradiation and the blueshifted absorption lines is problematic, particularly in the case of GRO J1655–40. Observations of this source imply wind densities about two orders of magnitude higher than theoretically predicted. This discrepancy does not mean that these “thermal disk winds” cannot explain blueshifted absorption in other systems, nor that they are unimportant as a sink of matter. Motivated by the inevitability of thermal disk winds and wealth of data taken with current observatories such as Chandra, XMM-Newton, and Suzaku, as well as the future AstroH mission, we decided to investigate the requirements to produce very dense winds. Using physical arguments, hydrodynamical simulations, and absorption-line calculations, we found that modification of the heating and cooling rates by a factor of a few results in an increase of the wind density of up to an order of magnitude and the wind velocity by a factor of about two. Therefore, the mass-loss rate from the disk can be one, if not even two, orders of magnitude higher than the accretion rate onto the central object. Such a high mass-loss rate is expected to destabilize the disk and perhaps provides a mechanism for state change.

  5. Explaining observations of rapidly rotating neutron stars in low-mass x-ray binaries

    NASA Astrophysics Data System (ADS)

    Gusakov, Mikhail E.; Chugunov, Andrey I.; Kantor, Elena M.

    2014-09-01

    In a previous paper [M. E. Gusakov, A. I. Chugunov, and E. M. Kantor, Phys. Rev. Lett. 112, 151101 (2014)], we introduced a new scenario that explains the existence of rapidly rotating warm neutron stars (NSs) observed in low-mass x-ray binaries (LMXBs). Here it is described in more detail. The scenario takes into account the interaction between superfluid inertial modes and the normal (quadrupole) m=2 r mode, which can be driven unstable by the Chandrasekhar-Friedman-Schutz (CFS) mechanism. This interaction can only occur at some fixed "resonance" stellar temperatures; it leads to formation of the "stability peaks" which stabilize a star in the vicinity of these temperatures. We demonstrate that a NS in LMXB spends a substantial fraction of time on the stability peak, that is, in the region of stellar temperatures and spin frequencies that has been previously thought to be CFS unstable with respect to excitation of r modes. We also find that the spin frequencies of NSs are limited by the CFS instability of normal (octupole) m=3 r mode rather than by m=2 r mode. This result agrees with the predicted value of the cutoff spin frequency ˜730 Hz in the spin distribution of accreting millisecond x-ray pulsars. In addition, we analyze evolution of a NS after the end of the accretion phase and demonstrate that millisecond pulsars can be born in LMXBs within our scenario. Besides millisecond pulsars, our scenario also predicts a new class of LMXB descendants—hot and rapidly rotating nonaccreting NSs ("hot widows"/HOFNARs). Further comparison of the proposed theory with observations of rotating NSs can impose new important constraints on the properties of superdense matter.

  6. Coronae and Winds from Irradiated Disks in X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Higginbottom, Nick; Proga, Daniel

    2015-07-01

    X-ray and UV line emission in X-ray binaries (XRBs) can be accounted for by a hot corona. Such a corona forms through irradiation of the outer disk by radiation produced in the inner accretion flow. The same irradiation can produce a strong outflow from the disk at sufficiently large radii. Outflowing gas has been recently detected in several XRBs via blueshifted absorption lines. However, the causal connection between winds produced by irradiation and the blueshifted absorption lines is problematic, particularly in the case of GRO J1655-40. Observations of this source imply wind densities about two orders of magnitude higher than theoretically predicted. This discrepancy does not mean that these “thermal disk winds” cannot explain blueshifted absorption in other systems, nor that they are unimportant as a sink of matter. Motivated by the inevitability of thermal disk winds and wealth of data taken with current observatories such as Chandra, XMM-Newton, and Suzaku, as well as the future AstroH mission, we decided to investigate the requirements to produce very dense winds. Using physical arguments, hydrodynamical simulations, and absorption-line calculations, we found that modification of the heating and cooling rates by a factor of a few results in an increase of the wind density of up to an order of magnitude and the wind velocity by a factor of about two. Therefore, the mass-loss rate from the disk can be one, if not even two, orders of magnitude higher than the accretion rate onto the central object. Such a high mass-loss rate is expected to destabilize the disk and perhaps provides a mechanism for state change.

  7. EXPLORING X-RAY BINARY POPULATIONS IN COMPACT GROUP GALAXIES WITH CHANDRA

    SciTech Connect

    Tzanavaris, P.; Hornschemeier, A. E.; Desjardins, T. D.; Walker, L. M.; Johnson, K. E.; Mulchaey, J. S.

    2016-02-01

    We obtain total galaxy X-ray luminosities, L{sub X}, originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the great majority of our galaxies, we find that the detected point sources most likely are local to their associated galaxy, and are thus extragalactic X-ray binaries (XRBs) or nuclear active galactic nuclei (AGNs). For spiral and irregular galaxies, we find that, after accounting for AGNs and nuclear sources, most CG galaxies are either within the ±1σ scatter of the Mineo et al. L{sub X}–star formation rate (SFR) correlation or have higher L{sub X} than predicted by this correlation for their SFR. We discuss how these “excesses” may be due to low metallicities and high interaction levels. For elliptical and S0 galaxies, after accounting for AGNs and nuclear sources, most CG galaxies are consistent with the Boroson et al. L{sub X}–stellar mass correlation for low-mass XRBs, with larger scatter, likely due to residual effects such as AGN activity or hot gas. Assuming non-nuclear sources are low- or high-mass XRBs, we use appropriate XRB luminosity functions to estimate the probability that stochastic effects can lead to such extreme L{sub X} values. We find that, although stochastic effects do not in general appear to be important, for some galaxies there is a significant probability that high L{sub X} values can be observed due to strong XRB variability.

  8. Dip Spectroscopy of the Low Mass X-Ray Binary XB 1254-690

    NASA Technical Reports Server (NTRS)

    Smale, Alan P.; Church, M. J.; BalucinskaChurch, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We observed the low mass X-ray binary XB 1254-690 with the Rossi X-ray Timing Explorer in 2001 May and December. During the first observation strong dipping on the 3.9-hr orbital period and a high degree of variability were observed, along with "shoulders" approx. 15% deep during extended intervals on each side of the main dips. The first observation also included pronounced flaring activity. The non-dip spectrum obtained using the PCA instrument was well-described by a two-component model consisting of a blackbody with kT = 1.30 +/- 0.10 keV plus a cut-off power law representation of Comptonized emission with power law photon index 1.10 +/- 0.46 and a cut-off energy of 5.9(sup +3.0, sub -1.4) keV. The intensity decrease in the shoulders of dipping is energy-independent, consistent with electron scattering in the outer ionized regions of the absorber. In deep dipping the depth of dipping reached 100%, in the energy band below 5 keV, indicating that all emitting regions were covered by absorber. Intensity-selected dip spectra were well-fit by a model in which the point-like blackbody is rapidly covered, while the extended Comptonized emission is progressively overlapped by the absorber, with the, covering fraction rising to 95% in the deepest portion of the dip. The intensity of this component in the dip spectra could be modeled by a combination of electron scattering and photoelectric absorption. Dipping did not occur during the 2001 December observation, but remarkably, both bursting and flaring were observed contemporaneously.

  9. Hubble Space Telescope Imaging of Bright Galactic X-Ray Binaries in Crowded Fields

    NASA Technical Reports Server (NTRS)

    Deutsch, Eric W.; Margon, Bruce; Wachter, Stefanie; Anderson, Scott F.

    1996-01-01

    We report high spatial resolution HST imagery and photometry of three well-studied, intense Galactic X-ray binaries, X2129+470, CAL 87, and GX 17+2. All three sources exhibit important anomalies that are not readily interpreted by conventional models. Each source also lies in a severely crowded field, and in all cases the anomalies would be removed if much of the light observed from the ground in fact came from a nearby, thus far unresolved superposed companion. For V1727 Cyg (X2129+470), we find no such companion. We also present an HST FOS spectrum and broadband photometry which is consistent with a single, normal star. The supersoft LMC X-ray source CAL 87 was already known from ground-based work to have a companion separated by O.9 minutes from the optical counterpart; our HST images clearly resolve these objects and yield the discovery of an even closer, somewhat fainter additional companion. Our photometry indicates that contamination is not severe outside eclipse, where the companions only contribute 20% of the light in V, but during eclipse more than half of the V light comes from the companions. The previously determined spectral type of the CAL 87 secondary may need to be reevaluated due to this significant contamination, with consequences on inferences of the mass of the components. We find no companions to NP Ser (= X1813-14, = GX 17+2). However, for this object we point out a small but possibly significant astrometric discrepancy between the position of the optical object and that of the radio source which is the basis for the identification. This discrepancy needs to be clarified.

  10. Orbital and superorbital monitoring of the Be/X-ray binary A0538-66: constraints on the system parameters

    NASA Astrophysics Data System (ADS)

    Rajoelimanana, A. F.; Charles, P. A.; Meintjes, P. J.; Townsend, L. J.; Schurch, M. P. E.; Udalski, A.

    2017-02-01

    We combine the decade-long photometry of the Be/X-ray binary system A0538-66 provided by the Massive astrophysical compact halo object (MACHO) and optical gravitational lensing experiment (OGLE) IV projects with high-resolution Southern African Large Telescope (SALT) spectroscopy to provide detailed constraints on the orbital parameters and system properties. The ˜420 d superorbital modulation is present throughout, but has reduced in amplitude in recent years. The well-defined 16.6409 d orbital outbursts, which were a strong function of superorbital phase in the MACHO data (not occurring at all at superorbital maximum), are present throughout the OGLE IV coverage. However, their amplitude reduces during superorbital maximum. We have refined the orbital period and ephemeris of the optical outburst based on ˜25 yr light curves to HJD = 2455674.48 ± 0.03 + n*16.6409 ± 0.0003d. Our SALT spectra reveal a B1 III star with vsin i of 285 kms-1 from which we have derived an orbital radial velocity curve which confirms the high eccentricity of e = 0.72 ± 0.14. Furthermore, the mass function indicates that, unless the neutron star far exceeds the canonical 1.44 M⊙, the donor must be significantly undermassive for its spectral type. We discuss the implications of the geometry and our derived orbital solution on the observed behaviour of the system.

  11. X-Ray Outbursts of ESO 243-49 HLX-1: Comparison with Galactic Low-mass X-Ray Binary Transients

    NASA Astrophysics Data System (ADS)

    Yan, Zhen; Zhang, Wenda; Soria, Roberto; Altamirano, Diego; Yu, Wenfei

    2015-09-01

    We studied the outburst properties of the hyper-luminous X-ray source ESO 243-49 HLX-1, using the full set of Swift monitoring observations. We quantified the increase in the waiting time, recurrence time, and e-folding rise timescale along the outburst sequence, and the corresponding decrease in outburst duration, total radiated energy, and e-folding decay timescale, which confirms previous findings. HLX-1 spends less and less time in outburst and more and more time in quiescence, but its peak luminosity remains approximately constant. We compared the HLX-1 outburst properties with those of bright Galactic low-mass X-ray binary transients (LMXBTs). Our spectral analysis strengthens the similarity between state transitions in HLX-1 and those in Galactic LMXBTs. We also found that HLX-1 follows the nearly linear correlations between the hard-to-soft state transition luminosity and the peak luminosity, and between the rate of change of X-ray luminosity during the rise phase and the peak luminosity, which indicates that the occurrence of the hard-to-soft state transition of HLX-1 is similar to those of Galactic LMXBTs during outbursts. We found that HLX-1 does not follow the correlations between total radiated energy and peak luminosity, and between total radiated energy and e-folding rise/decay timescales we had previously identified in Galactic LMXBTs. HLX-1 would follow those correlations if the distance were several hundreds of kiloparsecs. However, invoking a much closer distance for HLX-1 is not a viable solution to this problem, as it introduces other, more serious inconsistencies with the observations.

  12. Interpreting the radio/X-ray correlation of black hole X-ray binaries based on the accretion-jet model

    NASA Astrophysics Data System (ADS)

    Xie, Fu-Guo; Yuan, Feng

    2016-03-01

    Two types of correlations between the radio and X-ray luminosities (LR and LX) have been found in black hole X-ray binaries. For some sources, they follow the `original' type of correlation which is described by a single power law. Later it was found that some other sources follow a different correlation consisting of three power-law branches, with each branch having different power-law indexes. In this work, we explain these two types of correlation under the coupled accretion-jet model. We attribute the difference between these two types of sources to the different value of viscosity parameter α. One possible reason for different α is the different configuration of magnetic field in the accretion material coming from the companion stars. For the `single power-law' sources, their α is high; so their accretion is always in the mode of advection-dominated accretion flow (ADAF) for the whole range of X-ray luminosity. For those `hybrid power-law' sources, the value of α is small so their accretion mode changes from an ADAF to a luminous hot accretion flow, and eventually to two-phase accretion as the accretion rate increases. Because the dependence of radiative efficiency on the mass accretion rate is different for these three accretion modes, different power-law indexes in the LR-LX correlation are expected. Constraints on the ratio of the mass-loss rate into the jet and the mass accretion rate in the accretion flow are obtained, which can be tested in future by radiative magnetohydrodynamic numerical simulations of jet formation.

  13. The Effect of Variability on X-Ray Binary Luminosity Functions: Multiple-epoch Observations of NGC 300 with Chandra

    NASA Astrophysics Data System (ADS)

    Binder, B.; Gross, J.; Williams, B. F.; Eracleous, M.; Gaetz, T. J.; Plucinsky, P. P.; Skillman, E. D.

    2017-01-01

    We have obtained three epochs of Chandra ACIS-I observations (totaling ∼184 ks) of the nearby spiral galaxy NGC 300 to study the logN–logS distributions of its X-ray point-source population down to ∼2 × 10‑15 erg s‑1 cm‑2 in the 0.35–8 keV band (equivalent to ∼1036 erg s‑1). The individual epoch logN–logS distributions are best described as the sum of a background active galactic nucleus (AGN) component, a simple power law, and a broken power law, with the shape of the logN–logS distributions sometimes varying between observations. The simple power law and AGN components produce a good fit for “persistent” sources (i.e., with fluxes that remain constant within a factor of ∼2). The differential power-law index of ∼1.2 and high fluxes suggest that the persistent sources intrinsic to NGC 300 are dominated by Roche-lobe-overflowing low-mass X-ray binaries. The variable X-ray sources are described by a broken power law, with a faint-end power-law index of ∼1.7, a bright-end index of ∼2.8–4.9, and a break flux of ∼ 8× {10}-15 erg s‑1 cm‑2 (∼4 × 1036 erg s‑1), suggesting that they are mostly outbursting, wind-fed high-mass X-ray binaries, although the logN–logS distribution of variable sources likely also contains low-mass X-ray binaries. We generate model logN–logS distributions for synthetic X-ray binaries and constrain the distribution of maximum X-ray fluxes attained during outburst. Our observations suggest that the majority of outbursting X-ray binaries occur at sub-Eddington luminosities, where mass transfer likely occurs through direct wind accretion at ∼1%–3% of the Eddington rate.

  14. A `high-hard' outburst of the black hole X-ray binary GS 1354-64

    NASA Astrophysics Data System (ADS)

    Koljonen, K. I. I.; Russell, D. M.; Corral-Santana, J. M.; Armas Padilla, M.; Muñoz-Darias, T.; Lewis, F.; Coriat, M.; Bauer, F. E.

    2016-07-01

    We study in detail the evolution of the 2015 outburst of GS 1354-64 (BW Cir) at optical, UV and X-ray wavelengths using Faulkes Telescope South/Las Cumbres Observatory Global Telescope Network, Small & Moderate Aperture Research Telescope System and Swift. The outburst was found to stay in the hard X-ray state, albeit being anomalously luminous with a peak luminosity of LX > 0.15 LEdd, which could be the most luminous hard state observed in a black hole X-ray binary. We found that the optical/UV emission is tightly correlated with the X-ray emission, consistent with accretion disc irradiation and/or a jet producing the optical emission. The X-ray spectra can be fitted well with a Comptonization model, and show softening towards the end of the outburst. In addition, we detect a QPO in the X-ray light curves with increasing centroid frequency during the peak and decay periods of the outburst. The long-term optical light curves during quiescence show a statistically significant, slow rise of the source brightness over the 7 years prior to the 2015 outburst. This behaviour as well as the outburst evolution at all wavelengths studied can be explained by the disc instability model with irradiation and disc evaporation/condensation.

  15. TESTS OF GENERAL RELATIVITY IN THE STRONG-GRAVITY REGIME BASED ON X-RAY SPECTROPOLARIMETRIC OBSERVATIONS OF BLACK HOLES IN X-RAY BINARIES

    SciTech Connect

    Krawczynski, Henric

    2012-08-01

    Although general relativity (GR) has been tested extensively in the weak-gravity regime, similar tests in the strong-gravity regime are still missing. In this paper, we explore the possibility to use X-ray spectropolarimetric observations of black holes in X-ray binaries to distinguish between the Kerr metric and the phenomenological metrics introduced by Johannsen and Psaltis (which are not vacuum solutions of Einstein's equation) and thus to test the no-hair theorem of GR. To this end, we have developed a numerical code that calculates the radial brightness profiles of accretion disks and parallel transports the wave vector and polarization vector of photons through the Kerr and non-GR spacetimes. We used the code to predict the observational appearance of GR and non-GR accreting black hole systems. We find that the predicted energy spectra and energy-dependent polarization degree and polarization direction do depend strongly on the underlying spacetime. However, for large regions of the parameter space, the GR and non-GR metrics lead to very similar observational signatures, making it difficult to observationally distinguish between the two types of models.

  16. Combining Fits of The Optical Photometry and X-ray Spectra of the Low Mass X-ray Binary V1408 Aquilae.

    NASA Astrophysics Data System (ADS)

    Gomez, Sebastian; Mason, Paul A.; Robinson, Edward L.

    2015-01-01

    V1408 Aquilae is a binary system with a black hole primary accreting matter from a low mass secondary. We observed the system at the McDonald Observatory and collected 126 hours of high speed optical photometry on the source. We modeled the optical light curve using the XRbinary light curve synthesis software. The best fits to the optical light curve seem to suggest that the primary is a low mass black hole, however we cannot exclude some high mass solutions. Our models slightly favor a 3 solar mass primary at an inclination of about 13 degrees. In order to further constrain these parameters, and verify their validity we compared the fits of the optical light curve to fits to the X-ray spectra of the source. Using data from the Chandra Transmission Grating Catalog and Archive and the ISIS software analysis package we modeled the spectra of the source with a multi-temperature blackbody for a relativistic accretion disk around a spinning black hole and an additional photon power law component. The fits to the optical lightcurve and X-ray spectra are in agreement, from this we conclude that the case for V1408 Aql to be at a low inclination and harbor a low mass black hole is plausible.

  17. Circinus X-1: a Laboratory for Studying the Accretion Phenomenon in Compact Binary X-Ray Sources. Ph.D. Thesis - Maryland Univ.

    NASA Technical Reports Server (NTRS)

    Robinson-Saba, J. L.

    1983-01-01

    Observations of the binary X-ray source Circinus X-1 provide samples of a range of spectral and temporal behavior whose variety is thought to reflect a broad continuum of accretion conditions in an eccentric binary system. The data support an identification of three or more X-ray spectral components, probably associated with distinct emission regions.

  18. First Detection of the Hatchett-McCray Effect in the High-Mass X-ray Binary

    NASA Technical Reports Server (NTRS)

    Sonneborn, G.; Iping, R. C.; Kaper, L.; Hammerschiag-Hensberge, G.; Hutchings, J. B.

    2004-01-01

    The orbital modulation of stellar wind UV resonance line profiles as a result of ionization of the wind by the X-ray source has been observed in the high-mass X-ray binary 4U1700-37/HD 153919 for the first time. Far-UV observations (905-1180 Angstrom, resolution 0.05 Angstroms) were made at the four quadrature points of the binary orbit with the Far Ultraviolet Spectroscopic Explorer (FUSE) in 2003 April and August. The O6.5 laf primary eclipses the X-ray source (neutron star or black hole) with a 3.41-day period. Orbital modulation of the UV resonance lines, resulting from X-ray photoionization of the dense stellar wind, the so-called Hatchett-McCray (HM) effect, was predicted for 4U1700-37/HD153919 (Hatchett 8 McCray 1977, ApJ, 211, 522) but was not seen in N V 1240, Si IV 1400, or C IV 1550 in IUE and HST spectra. The FUSE spectra show that the P V 1118-1128 and S IV 1063-1073 P-Cygni lines appear to vary as expected for the HM effect, weakest at phase 0.5 (X-ray source conjunction) and strongest at phase 0.0 (X-ray source eclipse). The phase modulation of the O VI 1032-1037 lines, however, is opposite to P V and S IV, implying that O VI may be a byproduct of the wind's ionization by the X-ray source. Such variations were not observed in N V, Si IV, and C IV because of their high optical depth. Due to their lower cosmic abundance, the P V and S IV wind lines are unsaturated, making them excellent tracers of the ionization conditions in the O star's wind.

  19. M31 GLOBULAR CLUSTER STRUCTURES AND THE PRESENCE OF X-RAY BINARIES

    SciTech Connect

    Agar, J. R. R.; Barmby, P.

    2013-11-01

    The Andromeda galaxy, M31, has several times the number of globular clusters found in the Milky Way. It contains a correspondingly larger number of low-mass X-ray binaries (LMXBs) associated with globular clusters, and as such can be used to investigate the cluster properties that lead to X-ray binary formation. The best tracer of the spatial structure of M31 globulars is the high-resolution imaging available from the Hubble Space Telescope (HST), and we have used HST data to derive structural parameters for 29 LMXB-hosting M31 globular clusters. These measurements are combined with structural parameters from the literature for a total of 41 (of 50 known) LMXB clusters and a comparison sample of 65 non-LMXB clusters. Structural parameters measured in blue bandpasses are found to be slightly different (smaller core radii and higher concentrations) than those measured in red bandpasses; this difference is enhanced in LMXB clusters and could be related to stellar population differences. Clusters with LMXBs show higher collision rates for their mass compared to clusters without LMXBs, and collision rates estimated at the core radius show larger offsets than rates estimated at the half-light radius. These results are consistent with the dynamical formation scenario for LMXBs. A logistic regression analysis finds that, as expected, the probability of a cluster hosting an LMXB increases with increasing collision rate and proximity to the galaxy center. The same analysis finds that probability of a cluster hosting an LMXB decreases with increasing cluster mass at a fixed collision rate, although we caution that this could be due to sample selection effects. Metallicity is found to be a less important predictor of LMXB probability than collision rate, mass, or distance, even though LMXB clusters have a higher metallicity on average. This may be due to the interaction of location and metallicity: a sample of M31 LMXBs with a greater range in galactocentric distance would

  20. Population synthesis of ultracompact X-ray binaries in the Galactic bulge

    NASA Astrophysics Data System (ADS)

    van Haaften, L. M.; Nelemans, G.; Voss, R.; Toonen, S.; Portegies Zwart, S. F.; Yungelson, L. R.; van der Sluys, M. V.

    2013-04-01

    Aims: We model the present-day number and properties of ultracompact X-ray binaries (UCXBs) in the Galactic bulge. The main objective is to compare the results to the known UCXB population as well as to data from the Galactic Bulge Survey, in order to learn about the formation of UCXBs and their evolution, such as the onset of mass transfer and late-time behavior. Methods: The binary population synthesis code SeBa and detailed stellar evolutionary tracks have been used to model the UCXB population in the Bulge. The luminosity behavior of UCXBs has been predicted using long-term X-ray observations of the known UCXBs as well as the thermal-viscous disk instability model. Results: In our model, the majority of UCXBs initially have a helium burning star donor. Of the white dwarf donors, most have helium composition. In the absence of a mechanism that destroys old UCXBs, we predict (0.2-1.9) × 105 UCXBs in the Galactic bulge, depending on assumptions, mostly at orbital periods longer than 60 min (a large number of long-period systems also follows from the observed short-period UCXB population). About 5-50 UCXBs should be brighter than 1035 ergs-1, mostly persistent sources with orbital periods shorter than about 30 min and with degenerate helium and carbon-oxygen donors. This is about one order of magnitude more than the observed number of (probably) three. Conclusions: This overprediction of short-period UCXBs by roughly one order of magnitude implies that fewer systems are formed, or that a super-Eddington mass transfer rate is more difficult to survive than we assumed. The very small number of observed long-period UCXBs with respect to short-period UCXBs, the surprisingly high luminosity of the observed UCXBs with orbital periods around 50 min, and the properties of the PSR J1719-1438 system all point to much faster UCXB evolution than expected from angular momentum loss via gravitational wave radiation alone. Old UCXBs, if they still exist, probably have orbital

  1. Hydrodynamic, Atomic Kinetic, and Monte Carlo Radiation Transfer Models of the X-ray Spectra of Compact Binaries

    SciTech Connect

    Mauche, C W; Liedahl, D A; Akiyama, S; Plewa, T

    2008-02-08

    We describe the results of an effort, funded by the Lawrence Livermore National Laboratory Directed Research and Development Program, to model, using FLASH time-dependent adaptive-mesh hydrodynamic simulations, XSTAR photoionization calculations, HULLAC atomic data, and Monte Carlo radiation transport, the radiatively-driven photoionized wind and accretion flow of high-mass X-ray binaries (HMXBs). In this final report, we describe the purpose, approach, and technical accomplishments of this effort, including maps of the density, temperature, velocity, ionization parameter, and emissivity distributions of the X-ray emission lines of the well-studied HMXB Vela X-1.

  2. Does the Inner Disk Boundary of a Black Hole X-Ray Binary move During an Outburst?

    NASA Technical Reports Server (NTRS)

    Zhang, S. N.; Cui, W.; Chen, W.; Harmon, B. A.; Robinson, C. R.; Robinson, C. R.; Sun, X.; Yao, Y.; Zhang, X.

    2000-01-01

    Comptonization in the corona of an X-ray binary may reduce significantly the flux in the observed soft component of its X-ray spectrum. There fore the apparent inner disk radius inferred from the observed soft component may change in accordance to the fraction of the disk emission scattered into the hard component. We have developed a simple numerical model for carrying out the radiative transfer correction, in order to determine the original disk emission before the Comptonization in the hot corona. Applying this model to the extensive monitoring data of several black hole X-ray binaries with RXTE, we have found that most of the previous 1 y reported inner disk radius variations may be explained as due to this radiative transfer effect in the corona. We thus conclude that there is currently no evidence for significant inner disk boundary movement during the outbursts of these black hole X-ray binaries we have studied with the RXTE data.: GROJ1655-40, XTEJ1550-564, XTEJ1748-288 and XTEJ2012+381.

  3. On the Weak-Wind Problem in Massive Stars: X-Ray Spectra Reveal a Massive Hot Wind in mu Columbae

    NASA Technical Reports Server (NTRS)

    Huenemoerder, David P.; Oskinova, Lidia M.; Ignace, Richard; Waldron, Wayne L.; Todt, Helge; Hamaguchi, Kenji; Kitamoto, Shunji

    2012-01-01

    Mu Columbae is a prototypical weak-wind O star for which we have obtained a high-resolution X-ray spectrum with the Chandra LETG/ACIS instrument and a low-resolution spectrum with Suzaku. This allows us, for the first time, to investigate the role of X-rays on the wind structure in a bona fide weak-wind system and to determine whether there actually is a massive hot wind. The X-ray emission measure indicates that the outflow is an order of magnitude greater than that derived from UV lines and is commensurate with the nominal wind-luminosity relationship for O stars. Therefore, the "weak-wind problem"--identified from cool wind UV/optical spectra--is largely resolved by accounting for the hot wind seen in X-rays. From X-ray line profiles, Doppler shifts, and relative strengths, we find that this weak-wind star is typical of other late O dwarfs. The X-ray spectra do not suggest a magnetically confined plasma-the spectrum is soft and lines are broadened; Suzaku spectra confirm the lack of emission above 2 keV. Nor do the relative line shifts and widths suggest any wind decoupling by ions. The He-like triplets indicate that the bulk of the X-ray emission is formed rather close to the star, within five stellar radii. Our results challenge the idea that some OB stars are "weak-wind" stars that deviate from the standard wind-luminosity relationship. The wind is not weak, but it is hot and its bulk is only detectable in X-rays.

  4. On the Weak-wind Problem in Massive Stars: X-Ray Spectra Reveal a Massive Hot Wind in μ Columbae

    NASA Astrophysics Data System (ADS)

    Huenemoerder, David P.; Oskinova, Lidia M.; Ignace, Richard; Waldron, Wayne L.; Todt, Helge; Hamaguchi, Kenji; Kitamoto, Shunji

    2012-09-01

    μ Columbae is a prototypical weak-wind O star for which we have obtained a high-resolution X-ray spectrum with the Chandra LETG/ACIS instrument and a low-resolution spectrum with Suzaku. This allows us, for the first time, to investigate the role of X-rays on the wind structure in a bona fide weak-wind system and to determine whether there actually is a massive hot wind. The X-ray emission measure indicates that the outflow is an order of magnitude greater than that derived from UV lines and is commensurate with the nominal wind-luminosity relationship for O stars. Therefore, the "weak-wind problem"—identified from cool wind UV/optical spectra—is largely resolved by accounting for the hot wind seen in X-rays. From X-ray line profiles, Doppler shifts, and relative strengths, we find that this weak-wind star is typical of other late O dwarfs. The X-ray spectra do not suggest a magnetically confined plasma—the spectrum is soft and lines are broadened; Suzaku spectra confirm the lack of emission above 2 keV. Nor do the relative line shifts and widths suggest any wind decoupling by ions. The He-like triplets indicate that the bulk of the X-ray emission is formed rather close to the star, within five stellar radii. Our results challenge the idea that some OB stars are "weak-wind" stars that deviate from the standard wind-luminosity relationship. The wind is not weak, but it is hot and its bulk is only detectable in X-rays.

  5. HD 74194, a new binary supergiant fast X-ray transient?, possible optical counterpart of INTEGRAL hard X-ray source IGR J08408-4503

    NASA Astrophysics Data System (ADS)

    Barba, Rodolfo; Gamen, Roberto; Morrell, Nidia

    2006-05-01

    HD 74194 is an O-type supergiant, classified as O8.5 Ib (f) (Walborn 1973, AJ 78, 1067), also suspected as single-lined binary (see Maiz Apellaniz et al. 2004, ApJS 151, 103). This star is being spectroscopically monitored as part of our program of study of massive binaries. We have obtained high-resolution spectra of HD 74194 with the Echelle spectrograph attached to the du Pont 2.5-m telescope at Las Campanas Observatory in 2006 May 18.00, 20.96, 22.00, and 22.97.

  6. Measuring X-ray Binary Accretion State Distributions in Extragalactic Environments using XMM-Newton

    NASA Astrophysics Data System (ADS)

    West, Lacey; Lehmer, Bret; Yukita, Mihoko; Hornschemeier, Ann E.; Ptak, Andrew; Wik, Daniel R.; Zezas, Andreas

    2017-01-01

    X-ray binary systems (XRBs) in the MW can exist in several different accretion states, and many have been found to vary along specific tracks on intensity-color diagrams. Observationally measuring the distributions of these accretion states in a variety of environments can aid in population synthesis modeling and ultimately help us understand the formation and evolution of XRBs and their compact object components (i.e., black holes and neutron stars). Recent innovative studies with NuSTAR have demonstrated the utility of color-color and intensity-color diagrams in differentiating between XRB accretion states in extragalactic environments (NGC 253, M83, and M31). The key to NuSTAR’s success is its sensitivity above »10keV, where spectral differences between accretion states are most pronounced. However, due to the relatively low spatial resolution and large background of NuSTAR, the constraints from these diagrams is limited to only bright sources in nearby galaxies. In this poster, we present evidence that XMM-Newton observations of M83 in the 4.0-12.0 keV range can be used to create similar color-intensity and color-color diagrams and therefore differentiate between these accretion states. We will further discuss plans to leverage XMM-Newton’s vast archive and 17-year baseline to dramatically expand studies of accretion state distributions and state transitions for XRB populations in extragalactic environments.

  7. On the spin period distribution in Be/X-ray binaries

    SciTech Connect

    Cheng, Z.-Q.; Shao, Y.; Li, X.-D.

    2014-05-10

    There is a remarkable correlation between the spin periods of the accreting neutron stars (NSs) in Be/X-ray binaries (BeXBs) and their orbital periods. Recently, Knigge et al. showed that the distribution of the spin periods contains two distinct subpopulations peaked at ∼10 s and ∼200 s, respectively, and suggested that they may be related to two types of supernovae for the formation of the NSs, i.e., core-collapse and electron-capture supernovae. Here we propose that the bimodal spin period distribution is likely to be ascribed to different accretion modes of the NSs in BeXBs. When the NS tends to capture material from the warped, outer part of the Be star disk and experiences giant outbursts, a radiatively cooling dominated disk is formed around the NS, which spins up the NS and is responsible for the short-period subpopulation. In BeXBs that are dominated by normal outbursts or are persistent, the accretion flow is advection-dominated or quasi-spherical. The spin-up process is accordingly inefficient, leading to longer periods of the neuron stars. The potential relation between the subpopulations and the supernova mechanism is also discussed.

  8. Low-mass X-ray binaries and globular clusters streamers and arcs in NGC 4278

    SciTech Connect

    D'Abrusco, R.; Fabbiano, G.; Brassington, N. J.

    2014-03-01

    We report significant inhomogeneities in the projected two-dimensional spatial distributions of low-mass X-ray binaries (LMXBs) and globular clusters (GCs) of the intermediate mass elliptical galaxy NGC 4278. In the inner region of NGC 4278, a significant arc-like excess of LMXBs extending south of the center at ∼50'' in the western side of the galaxy can be associated with a similar overdensity of the spatial distribution of red GCs from Brassington et al. Using a recent catalog of GCs produced by Usher et al. and covering the whole field of the NGC 4278 galaxy, we have discovered two other significant density structures outside the D {sub 25} isophote to the W and E of the center of NGC 4278, associated with an overdensity and an underdensity, respectively. We discuss the nature of these structures in the context of the similar spatial inhomogeneities discovered in the LMXBs and GCs populations of NGC 4649 and NGC 4261, respectively. These features suggest streamers from disrupted and accreted dwarf companions.

  9. The Binary Black Hole Merger Rate from Ultraluminous X-ray Source Progenitors

    NASA Astrophysics Data System (ADS)

    Finke, Justin; Razzaque, Soebur

    2017-01-01

    Ultraluminous X-ray sources (ULXs) exceed the Eddington luminosity for an approximately 10 solar mass black hole. The recent detection of a black hole merger event GW 150914 by the gravitational wave detector ALIGO indicates that black holes with mass greater than 10 do indeed exist. Motivated by this, we explore a scenario where ULXs consist of black holes formed by the collapse of high-mass, low-metallicity stars, and that these ULXs become binary black holes (BBHs) that eventually merge. We use empirical relations between the number of ULXs and the star formation rate and host galaxy metallicity to estimate the ULX formation rate and the BBH merger rate at all redshifts. This assumes the ULX rate is directly proportional to the star formation rate for a given metallicity, and that the black hole accretion rate is distributed as a log-normal distribution. We include an enhancement in the ULX formation rate at earlier epochs due to lower mean metallicities. Our model is able to reproduce both the rate and mass distribution of BBH mergers in the nearby universe inferred from the detection of GW 150914, LVT 151012, and GW 151226 by LIGO if the median accretion rate of ULXs is a factor 1 to 30 greater than the Eddington rate. Our predictions of the BBH merger rate, mass distribution.

  10. A test of truncation in the accretion discs of X-ray Binaries.

    NASA Astrophysics Data System (ADS)

    Eckersall, A.

    2016-06-01

    The truncated-disc model is generally used to help explain the change between the soft and hard states in X-ray Binaries, where the standard accretion disc is truncated in the inner regions and replaced by a radiatively inefficient accretion flow. There is still disagreement though in the extent of this truncation, particularly in at what point truncation begins. Here we analyze XMM EPIC-pn spectra in both the soft and hard states for a number of galactic XRBs, along with RGS data and the latest absorption and emission models to get an independent fit for the ISM column densities for each source. Specifically, we assume the 'canonical' model where the luminous accretion disc extends down to the innermost stable orbit at 6r_g, and construct a spectral model accounting for thermal, reflection and Compton processes ensuring consistent geometrical properties of the models. Rather than attempting to infer the inner disc location from spectral fitting and/or reflection models, we instead attempt a direct test of whether a consistent model will fit assuming no truncation. We discuss the implications for emission models of XRBs.

  11. X-Ray Absorption Spectroscopy and Computer Modelling Study of Nanocrystalline Binary Alkaline Earth Fluorides

    NASA Astrophysics Data System (ADS)

    Chadwick, A. V.; Düvel, A.; Heitjans, P.; Pickup, D. M.; Ramos, S.; Sayle, D. C.; Sayle, T. X. T.

    2015-04-01

    Nanocrystalline samples of Ba1-xCaxF2 prepared by high-energy milling show an unusually high F- ion conductivity, which exhibit a maximum in the magnitude and a minimum in the activation energy at x = 0.5. Here, we report an X-ray absorption spectroscopy (XAS) at the Ca and Sr K edges and the Ba L3 edge and a molecular dynamics (MD) simulation study of the pure and mixed fluorides. The XAS measurements on the pure binary fluorides, CaF2, SrF2 and BaF2 show that high-energy ball-milling produces very little amorphous material, in contrast to the results for ball milled oxides. XAS measurements of Ba1-xCaxF2 reveal that for 0 < x <1 there is considerable disorder in the local environments of the cations which is highest for x = 0.5. Hence the maximum in the conductivity corresponds to the composition with the maximum level of local disorder. The MD calculations also show a highly disordered structure consistent with the XAS results and similarly showing maximum disorder at x = 0.5.

  12. Inclination dependence of QPO phase lags in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    van den Eijnden, J.; Ingram, A.; Uttley, P.; Motta, S. E.; Belloni, T. M.; Gardenier, D. W.

    2017-01-01

    Quasi-periodic oscillations (QPOs) with frequencies from ˜0.05to30 Hz are a common feature in the X-ray emission of accreting black hole binaries. As the QPOs originate from the innermost accretion flow, they provide the opportunity to probe the behaviour of matter in extreme gravity. In this paper, we present a systematic analysis of the inclination dependence of phase lags associated with both type-B and type-C QPOs in a sample of 15 Galactic black hole binaries. We find that the phase lag at the type-C QPO frequency strongly depends on inclination, both in evolution with the QPO frequency and sign. Although we find that the type-B QPO soft lags are associated with high-inclination sources, the source sample is too small to confirm that this as a significant inclination dependence. These results are consistent with a geometrical origin of type-C QPOs and a different origin for type-B and type-C QPOs. We discuss the possibility that the phase lags originate from a pivoting spectral power law during each QPO cycle, while the inclination dependence arises from differences in dominant relativistic effects. We also search for energy dependences in the type-C QPO frequency. We confirm this effect in the three known sources (GRS 1915+105, H1743-322 and XTE J1550-564) and newly detect it in XTE J1859+226. Lastly, our results indicate that the unknown inclination sources XTE J1859+226 and MAXI J1543-564 are most consistent with a high inclination.

  13. The effect of vacuum birefringence on the polarization of X-ray binaries and pulsars

    NASA Technical Reports Server (NTRS)

    Novick, R.; Weisskopf, M. C.; Angel, J. R. P.; Sutherland, P. G.

    1977-01-01

    In a strong magnetic field the vacuum becomes birefringent. This effect is especially important for pulsars at X-ray wavelengths. Any polarized X-ray emission from the surface of a magnetic neutron star becomes depolarized as it propagates through the magnetic field. The soft X-ray emission from AM Her, believed to be a magnetic white dwarf, may show about one radian of phase retardation. In this case, circular polarization of the X-ray flux would be a characteristic signature of vacuum birefringence.

  14. The Effects of Common Envelope and Tidal Evolution On the Properties of X-ray Binaries, CVs and SN Ia

    NASA Astrophysics Data System (ADS)

    Moe, Maxwell C.; Di Stefano, R.

    2011-09-01

    Population synthesis studies provide an excellent testbed for determining the consequences and significance of certain binary processes that lead to accretion onto a compact object. We investigated the recent observational constraints of the common envelope (CE) efficiency parameter with particular regard to the dependence on the mass ratio of the binary. In our population synthesis calculations, we also implemented binary tidal interactions prior to Roche lobe overflow, such as tidal capture of and spin up by the companion, synchronization, and enhanced equatorial mass loss of the giant that can significantly alter the evolution of the system. Finally, we analyzed these binary interactions in the context of nuclear burning on white dwarfs, accreting X-ray binaries, cataclysmic variables, progenitors of Type Ia supernovae, and other high energy binary phenomena.

  15. Binary black hole merger rates inferred from luminosity function of ultra-luminous X-ray sources

    NASA Astrophysics Data System (ADS)

    Inoue, Yoshiyuki; Tanaka, Yasuyuki T.; Isobe, Naoki

    2016-10-01

    The Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) has detected direct signals of gravitational waves (GWs) from GW150914. The event was a merger of binary black holes whose masses are 36^{+5}_{-4} M_{{⊙}} and 29^{+4}_{-4} M_{{⊙}}. Such binary systems are expected to be directly evolved from stellar binary systems or formed by dynamical interactions of black holes in dense stellar environments. Here we derive the binary black hole merger rate based on the nearby ultra-luminous X-ray source (ULX) luminosity function (LF) under the assumption that binary black holes evolve through X-ray emitting phases. We obtain the binary black hole merger rate as 5.8(tULX/0.1 Myr)- 1λ- 0.6exp ( - 0.30λ) Gpc- 3 yr- 1, where tULX is the typical duration of the ULX phase and λ is the Eddington ratio in luminosity. This is coincident with the event rate inferred from the detection of GW150914 as well as the predictions based on binary population synthesis models. Although we are currently unable to constrain the Eddington ratio of ULXs in luminosity due to the uncertainties of our models and measured binary black hole merger event rates, further X-ray and GW data will allow us to narrow down the range of the Eddington ratios of ULXs. We also find the cumulative merger rate for the mass range of 5 M⊙ ≤ MBH ≤ 100 M⊙ inferred from the ULX LF is consistent with that estimated by the aLIGO collaboration considering various astrophysical conditions such as the mass function of black holes.

  16. Constraints on cold dark matter theories from observations of massive x-ray-luminous clusters of galaxies at high redshift

    NASA Technical Reports Server (NTRS)

    Luppino, G. A.; Gioia, I. M.

    1995-01-01

    During the course of a gravitational lensing survey of distant, X-ray selected Einstein Observatory Extended Medium Sensitivity Survey (EMSS) clusters of galaxies, we have studied six X-ray-luminous (L(sub x) greater than 5 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) clusters at redshifts exceeding z = 0.5. All of these clusters are apparently massive. In addition to their high X-ray luminosity, two of the clusters at z approximately 0.6 exhibit gravitationally lensed arcs. Furthermore, the highest redshift cluster in our sample, MS 1054-0321 at z = 0.826, is both extremely X-ray luminous (L(sub 0.3-3.5keV)=9.3 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) and exceedingly rich with an optical richness comparable to an Abell Richness Class 4 cluster. In this Letter, we discuss the cosmological implications of the very existence of these clusters for hierarchical structure formation theories such as standard Omega = 1 CDM (cold dark matter), hybrid Omega = 1 C + HDM (hot dark matter), and flat, low-density Lambda + CDM models.

  17. Absorption lines from magnetically driven winds in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Chakravorty, S.; Petrucci, P.-O.; Ferreira, J.; Henri, G.; Belmont, R.; Clavel, M.; Corbel, S.; Rodriguez, J.; Coriat, M.; Drappeau, S.; Malzac, J.

    2016-05-01

    Context. High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines suggesting the presence of outflowing winds. Furthermore, observations show that the disk winds are equatorial and they occur in the Softer (disk dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. Aims: We want to test whether the self-similar magneto-hydrodynamic (MHD) accretion-ejection models can explain the observational results for accretion disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free parameter. This mass loading is determined by solving the full set of dynamical MHD equations without neglecting any physical term. Thus, the physical properties of the outflow depend on and are controlled by the global structure of the disk. Methods: We studied different MHD solutions characterized by different values of the disk aspect ratio (ɛ) and the ejection efficiency (p). We also generate two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. Such heating could be either from dissipation of energy due to MHD turbulence in the disk or from illumination of the disk surface. Warm solutions can have large (>0.1) values of p, which would imply larger wind mass loading at the base of the outflow. We use each of these MHD solutions to predict the physical parameters (distance, density, velocity, magnetic field, etc.) of an outflow. Motivated by observational results, we have put limits on the ionization parameter (ξ), column density, and timescales. Further constraints were derived for the allowed values of ξ from thermodynamic instability considerations, particularly for the Hard SED. These physical constraints were imposed on each of these outflows to select regions within it, which are consistent with the observed winds. Results: The cold MHD solutions are found to be

  18. ROSAT Energy Spectra of Low-Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Schulz, N. S.

    1999-01-01

    The 0.1-2.4 keV bandpass of the ROSAT Position Sensitive Proportional Counter (PSPC) offers an opportunity to study the very soft X-ray continuum of bright low-mass X-ray binaries (LMXBs). In 46 pointed observations, 23 LMXBs were observed with count rates between 0.4 and 165.4 counts s-1. The survey identified a total of 29 different luminosity levels, which are compared with observations and identified spectral states from other missions. The atoll source 4U 1705-44 was observed near Eddington luminosities in an unusually high intensity state. Spectral analysis provided a measure of the interstellar column density for all 49 observations. The sensitivity of spectral fits depends strongly on column density. Fits to highly absorbed spectra are merely insensitive toward any particular spectral model. Sources with column densities well below 1022 cm-2 are best fitted by power laws, while the blackbody model gives clearly worse fits to the data. Most single-component fits from sources with low column densities, however, are not acceptable at all. The inclusion of a blackbody component in eight sources can improve the fits significantly. The obtained emission radii of less than 5 km suggest emission from the neutron star surface. In 10 sources acceptable fits can only be achieved by including soft-line components. With a spectral resolution of the PSPC of 320-450 eV, between 0.6 and 1.2 keV unresolved broad-line features were detected around 0.65, 0.85, and 1.0 keV. The line fluxes range within 10-11 and 10-12 ergs cm-2 s-1, with equivalent widths between 24 and 210 eV. In LMC X-2, 2S 0918-549, and 4U 1254-690, line emission is indicated for the first time. The soft emission observed in 4U 0614+091 compares with recent ASCA results, with a new feature indicated at 1.31 keV. The deduced line fluxes in 4U 1820-30 and Cyg X-2 showed variability of a factor of 2 within timescales of 1-2 days. Average fluxes of line components in 4U 1820-30 varied by the same factor over a

  19. The Discovery of a Second Luminous Low-Mass X-Ray Binary in the Globular Cluster M15

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Angelini, Lorella

    2001-01-01

    We report an observation by the Chandra X-Ray Observatory of 4U 2127+119, the X-ray source identified with the globular cluster M15. The Chandra observation reveals that 4U 2127+119 is in fact two bright sources, separated by 2.7 arcsec. One source is associated with AC 211, the previously identified optical counterpart to 4U 2127+119, a low-mass X-ray binary (LMXB). The second source, M15 X-2, is coincident with a 19th U magnitude blue star that is 3.3 arcsec from the cluster core. The Chandra count rate of M15 X-2 is 2.5 times higher than that of AC 211. Prior to the 0.5 arcsec imaging capability of Chandra, the presence of two so closely separated bright sources would not have been resolved. The optical counterpart, X-ray luminosity, and spectrum of M15 X-2 are consistent with it also being an LMXB system. This is the first time that two LMXBs have been seen to be simultaneously active in a globular cluster. The discovery of a second active LMXB in M15 solves a long-standing puzzle where the properties of AC 211 appear consistent with it being dominated by an extended accretion disk corona, and yet 4U 2127+119 also shows luminous X-ray bursts requiring that the neutron star be directly visible. The resolution of 4U 2127+119 into two sources suggests that the X-ray bursts did not come from AC 211 but rather from M15 X-2. We discuss the implications of this discovery for understanding the origin and evolution of LMXBs in globular clusters as well as X-ray observations of globular clusters in nearby galaxies.

  20. The Discovery of a Second Luminous Low Mass X-ray Binary in the Globular Cluster M15

    NASA Technical Reports Server (NTRS)

    White, Nicholas E.; Angelini, Lorella

    2001-01-01

    We report an observation by the Chandra X-ray Observatory of 4U2127+119, the X-ray source identified with the globular cluster M15. The Chandra observation reveals that 4U2127+119 is in fact two bright sources, separated by 2.7". One source is associated with AC21 1, the previously identified optical counterpart to 4U2127+119, a low mass X-ray binary (LMXB). The second source, M15-X2, is coincident with a 19th U magnitude blue star that is 3.3" from the cluster core. The Chandra count rate of M15-X2 is 2.5 times higher than that of AC211. Prior to the 0.5" imaging capability of Chandra the presence of two so closely separated bright sources would not have been resolved, The optical counterpart, X-ray luminosity and spectrum of M15-X2 are consistent with it also being an LMXB system. This is the first time that two LMXBS have been seen to be simultaneously active in a globular cluster. The discovery of a second active LMXB in M15 solves a long standing puzzle where the properties of AC211 appear consistent with it being dominated by an extended accretion disk corona, and yet 4U2127+119 also shows luminous X-ray bursts requiring that the neutron star be directly visible. The resolution of 4U2127+119 into two sources suggests that the X-ray bursts did not come from AC211, but rather from M15X2. We discuss the implications of this discovery for understanding the origin and evolution of LMXBs in GCs as well as X-ray observations of globular clusters in nearby galaxies.

  1. Rayleigh-Taylor Gravity Waves and Quasiperiodic Oscillation Phenomenon in X-ray Binaries

    NASA Technical Reports Server (NTRS)

    Titarchuk, Lev

    2002-01-01

    Accretion onto compact objects in X-ray binaries (black hole, neutron star (NS), white dwarf) is characterized by non-uniform flow density profiles. Such an effect of heterogeneity in presence of gravitational forces and pressure gradients exhibits Rayleigh-Taylor gravity waves (RTGW). They should be seen as quasiperiodic wave oscillations (QPO) of the accretion flow in the transition (boundary) layer between the Keplerian disk and the central object. In this paper the author shows that the main QPO frequency, which is very close to the Keplerian frequency, is split into separate frequencies (hybrid and low branch) under the influence of the gravitational forces in the rotational frame of reference. The RTGWs must be present and the related QPOs should be detected in any system where the gravity, buoyancy and Coriolis force effects cannot be excluded (even in the Earth and solar environments). The observed low and high QPO frequencies are an intrinsic signature of the RTGW. The author elaborates the conditions for the density profile when the RTGW oscillations are stable. A comparison of the inferred QPO frequencies with QPO observations is presented. The author finds that hectohertz frequencies detected from NS binaries can be identified as the RTGW low branch frequencies. The author also predicts that an observer can see the double NS spin frequency during the NS long (super) burst events when the pressure gradients and buoyant forces are suppressed. The Coriolis force is the only force which acts in the rotational frame of reference and its presence causes perfect coherent pulsations with a frequency twice of the NS spin. The QPO observations of neutron binaries have established that the high QPO frequencies do not go beyond of the certain upper limit. The author explains this observational effect as a result of the density profile inversions. Also the author demonstrates that a particular problem of the gravity waves in the rotational frame of reference in the

  2. Disk-jet coupling in the Galactic black hole X-ray binary MAXI J1836-194

    NASA Astrophysics Data System (ADS)

    Russell, Thomas

    2014-01-01

    There is a universal connection between the accretion and ejection phenomena that are observed in black holes across the mass scale. Quantifying this relationship is the first step in understanding how jets are launched, accelerated and collimated. X-ray binaries are ideal systems to study this relationship, as they evolve on human timescales. In outburst, their luminosities increase by several orders of magnitude, with the thermal X-ray emission from the accretion disk and the radio emission from the relativistic jets undergoing dramatic, coupled changes. We present the results of our multiwavelength radio through to X-ray observations of the Galactic black hole candidate X-ray binary MAXI J1836-194 during its 2011 outburst. We find that this system has a near face-on accretion disk with the jet, that is pointed almost directly towards us, accounting for ~6% of the total energy output of the system early in the outburst. We observed the frequency of the transition from optically thick to optically thin synchrotron emission in the jet spectrum evolve by ~3 orders of magnitude as the jet gradually switches on and off on a timescale of a few weeks. This evolution does not appear to follow the expected positive relation with source luminosity. Instead the jet break shifted to higher frequencies as the source luminosity decreased and is likely coupled to the accretion flow in a more complex way. We find the region where the jet is accelerated up to relativistic speeds occurs at much larger distances from the black hole than previously thought and does not scale with the inner radius of the accretion disk. Our simultaneous, high cadence observations provide an unprecedented insight into the accretion processes occurring during an outburst, allowing us to observe the compact jet evolve and the corresponding changes within the accretion regime. This has implications for the launching of jets on all scales, from X-ray binaries to their larger-scale analogues, AGN.

  3. Superorbital Periodic Modulation in Wind-Accretion High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

    NASA Technical Reports Server (NTRS)

    Corbet, Robin H. D.; Krimm, Hans A.

    2013-01-01

    We report the discovery using data from the Swift-Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418-4532, and IGR J16479-4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493-4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393-4643 (= AX J16390.4-4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, Rossi X-Ray Timing Explorer Proportional Counter Array, and International Gamma-Ray Astrophysics Laboratory light curves. 1E 1145.1-6141 may also be worthy of further attention due to the amount of low-frequency modulation of its light curve. However, we find that the presence of superorbital modulation is not a universal feature of wind-accretion supergiant X-ray binaries.

  4. A CHANGE IN THE QUIESCENT X-RAY SPECTRUM OF THE NEUTRON STAR LOW-MASS X-RAY BINARY MXB 1659-29

    SciTech Connect

    Cackett, E. M.; Brown, E. F.; Cumming, A.; Degenaar, N.; Miller, J. M.; Fridriksson, J. K.; Wijnands, R.; Homan, J.

    2013-09-10

    The quasi-persistent neutron star low-mass X-ray binary MXB 1659-29 went into quiescence in 2001, and we have followed its quiescent X-ray evolution since. Observations over the first 4 yr showed a rapid drop in flux and temperature of the neutron star atmosphere, interpreted as cooling of the neutron star crust which had been heated during the 2.5 yr outburst. However, observations taken approximately 1400 and 2400 days into quiescence were consistent with each other, suggesting the crust had reached thermal equilibrium with the core. Here we present a new Chandra observation of MXB 1659-29 taken 11 yr into quiescence and 4 yr since the last Chandra observation. This new observation shows an unexpected factor of {approx}3 drop in count rate and change in spectral shape since the last observation, which cannot be explained simply by continued cooling. Two possible scenarios are that either the neutron star temperature has remained unchanged and there has been an increase in the column density, or, alternatively the neutron star temperature has dropped precipitously and the spectrum is now dominated by a power-law component. The first scenario may be possible given that MXB 1659-29 is a near edge-on system, and an increase in column density could be due to build-up of material in, and a thickening of, a truncated accretion disk during quiescence. But, a large change in disk height may not be plausible if standard accretion disk theory holds during quiescence. Alternatively, the disk may be precessing, leading to a higher column density during this latest observation.

  5. Suzaku spectra of the neutron-star low-mass X-ray binary 4U 1608-52

    NASA Astrophysics Data System (ADS)

    Lei, Yajuan; Zhang, Haotong; zhang, Yanxia

    2015-08-01

    We present the spectral analysis of the neutron-star low-mass X-ray binary 4U 1608-52 using data from four Suzaku observations in 2010 March. 4U 1608-52 is a transient atoll source, and the analyzed observations contain the “island” and “banana” states, corresponding transitional, and soft states. The spectra are fitted with the hybrid model for the soft states, which consists of two thermal components (a multicolor accretion disk and a single-temperature blackbody) plus a broken power law. The fitting results show that the continuum spectra evolve during the different states. Fe emission line is often detected in low-mass X-ray binary, however, no obviously Fe line is detected in the four observations of 4U 1608-52.

  6. On the power spectra of the wind-fed X-ray binary pulsar GX 301 - 2

    NASA Technical Reports Server (NTRS)

    Orlandini, Mauro; Morfill, G. E.

    1992-01-01

    A phenomenological model of accretion which is applied to the wind-fed X-ray binary pulsar GX 301 - 2 is developed, assuming that the accretion onto the neutron star does not occur from a continuous flux of plasma, but from blobs of matter which are threaded by the magnetic field lines onto the magnetic polar caps of the neutron star. These 'lumps' are produced at the magnetospheric limit by magnetohydrodynamical instability, introducing a 'noise' in the accretion process, due to the discontinuity in the flux of matter onto the neutron star. This model is able to describe the change of slope observed in the continuum component of the power spectra of the X-ray binary pulsar GX 301 - 2, in the frequency range 0.01 - 0.1 Hz. The physical properties of the infalling blobs derived in the model are in agreement with the constraints imposed by observations.

  7. Constraining the formation of black holes in short-period black hole low-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Repetto, Serena; Nelemans, Gijs

    2015-11-01

    The formation of stellar-mass black holes (BHs) is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova (SN) event (if any) and the magnitude of the natal kick (NK) the BH receives at birth (if any). Repetto et al., studying the position of Galactic X-ray binaries containing BHs, found evidence for BHs receiving high NKs at birth. In this paper, we extend that study, taking into account the previous binary evolution of the sources as well. The seven short-period BH X-ray binaries that we use are compact binaries consisting of a low-mass star orbiting a BH in a period less than 1 d. We trace their binary evolution backwards in time, from the current observed state of mass transfer, to the moment the BH was formed, and we add the extra information on the kinematics of the binaries. We find that several systems could be explained by no NK, just mass ejection, while for two systems (and possibly more) a high kick is required. So unless the latter have an alternative formation, such as within a globular cluster, we conclude that at least some BHs get high kicks. This challenges the standard picture that BH kicks would be scaled down from neutron star kicks. Furthermore, we find that five systems could have formed with a non-zero NK but zero mass ejected (i.e. no SN) at formation, as predicted by neutrino-driven NKs.

  8. Reversibility of time series: revealing the hidden messages in X-ray binaries and cataclysmic variables

    NASA Astrophysics Data System (ADS)

    Scaringi, S.; Maccarone, T. J.; Middleton, M.

    2014-11-01

    We explore the non-linear, high-frequency, aperiodic variability properties in the three cataclysmic variables MV Lyr, KIC 8751494 and V1504 Cyg observed with Kepler, as well as the X-ray binary Cyg X-1 observed with RXTE. This is done through the use of a high-order Fourier statistic called the bispectrum and its related biphase and bicoherence, as well as the time-skewness statistic. We show how all objects display qualitatively similar biphase trends. In particular, all biphase amplitudes are found to be smaller than π/2, suggesting that the flux distributions for all sources are positively skewed on all observed time-scales, consistent with the lognormal distributions expected from the fluctuating accretion disc model. We also find that for all objects, the biphases are positive at frequencies where the corresponding power spectral densities display their high-frequency break. This suggests that the noise-like flaring observed is rising more slowly than it is falling, and thus not time-reversible. This observation is also consistent with the fluctuating accretion disc model. Furthermore, we observe the same qualitative biphase trends in all four objects, where the biphases display a distinct decrease at frequencies below the high-frequency break in their respective power spectral densities. This behaviour can also be observed in the time skewness of all four objects. As far as we are aware, there is no immediate explanation for the observed biphase decreases. The biphase decreases may thus suggest that the fluctuating accretion disc model begins to break down at frequencies below the high-frequency break.

  9. ACCRETION DISK DYNAMO AS THE TRIGGER FOR X-RAY BINARY STATE TRANSITIONS

    SciTech Connect

    Begelman, Mitchell C.; Armitage, Philip J.; Reynolds, Christopher S.

    2015-08-20

    Magnetohydrodynamic accretion disk simulations suggest that much of the energy liberated by the magnetorotational instability (MRI) can be channeled into large-scale toroidal magnetic fields through dynamo action. Under certain conditions, this field can dominate over gas and radiation pressure in providing vertical support against gravity, even close to the midplane. Using a simple model for the creation of this field, its buoyant rise, and its coupling to the gas, we show how disks could be driven into this magnetically dominated state and deduce the resulting vertical pressure and density profiles. Applying an established criterion for MRI to operate in the presence of a toroidal field, we show that magnetically supported disks can have two distinct MRI-active regions, separated by a “dead zone” where local MRI is suppressed, but where magnetic energy continues to flow upward from the dynamo region below. We suggest that the relative strengths of the MRI zones, and the local poloidal flux, determine the spectral states of X-ray binaries. Specifically, “intermediate” and “hard” accretion states occur when MRI is triggered in the hot, upper zone of the corona, while disks in “soft” states do not develop the upper MRI zone. We discuss the conditions under which various transitions should take place and speculate on the relationship of dynamo activity to the various types of quasi-periodic oscillations that sometimes appear in the hard spectral components. The model also explains why luminous accretion disks in the “soft” state show no signs of the thermal/viscous instability predicted by standard α-models.

  10. Sub-mm Jet Properties of the X-Ray Binary Swift J1745-26

    NASA Astrophysics Data System (ADS)

    Tetarenko, A. J.; Sivakoff, G. R.; Miller-Jones, J. C. A.; Curran, P. A.; Russell, T. D.; Coulson, I. M.; Heinz, S.; Maitra, D.; Markoff, S. B.; Migliari, S.; Petitpas, G. R.; Rupen, M. P.; Rushton, A. P.; Russell, D. M.; Sarazin, C. L.

    2015-05-01

    We present the results of our observations of the early stages of the 2012-2013 outburst of the transient black hole X-ray binary (BHXRB), Swift J1745-26, with the Very Large Array, Submillimeter Array, and James Clerk Maxwell telescope (SCUBA-2). Our data mark the first multiple-band mm and sub-mm observations of a BHXRB. During our observations the system was in the hard accretion state producing a steady, compact jet. The unique combination of radio and mm/sub-mm data allows us to directly measure the spectral indices in and between the radio and mm/sub-mm regimes, including the first mm/sub-mm spectral index measured for a BHXRB. Spectral fitting revealed that both the mm (230 GHz) and sub-mm (350 GHz) measurements are consistent with extrapolations of an inverted power law from contemporaneous radio data (1-30 GHz). This indicates that, as standard jet models predict, a power law extending up to mm/sub-mm frequencies can adequately describe the spectrum, and suggests that the mechanism driving spectral inversion could be responsible for the high mm/sub-mm fluxes (compared to radio fluxes) observed in outbursting BHXRBs. While this power law is also consistent with contemporaneous optical data, the optical data could arise from either jet emission with a jet spectral break frequency of {{ν }break}≳ 1× {{10}14} Hz or the combination of jet emission with a lower jet spectral break frequency of {{ν }break}≳ 2× {{10}11} Hz and accretion disk emission. Our analysis solidifies the importance of the mm/sub-mm regime in bridging the crucial gap between radio and IR frequencies in the jet spectrum, and justifies the need to explore this regime further.

  11. Accretion Disk Dynamo as the Trigger for X-Ray Binary State Transitions

    NASA Astrophysics Data System (ADS)

    Begelman, Mitchell C.; Armitage, Philip J.; Reynolds, Christopher S.

    2015-08-01

    Magnetohydrodynamic accretion disk simulations suggest that much of the energy liberated by the magnetorotational instability (MRI) can be channeled into large-scale toroidal magnetic fields through dynamo action. Under certain conditions, this field can dominate over gas and radiation pressure in providing vertical support against gravity, even close to the midplane. Using a simple model for the creation of this field, its buoyant rise, and its coupling to the gas, we show how disks could be driven into this magnetically dominated state and deduce the resulting vertical pressure and density profiles. Applying an established criterion for MRI to operate in the presence of a toroidal field, we show that magnetically supported disks can have two distinct MRI-active regions, separated by a “dead zone” where local MRI is suppressed, but where magnetic energy continues to flow upward from the dynamo region below. We suggest that the relative strengths of the MRI zones, and the local poloidal flux, determine the spectral states of X-ray binaries. Specifically, “intermediate” and “hard” accretion states occur when MRI is triggered in the hot, upper zone of the corona, while disks in “soft” states do not develop the upper MRI zone. We discuss the conditions under which various transitions should take place and speculate on the relationship of dynamo activity to the various types of quasi-periodic oscillations that sometimes appear in the hard spectral components. The model also explains why luminous accretion disks in the “soft” state show no signs of the thermal/viscous instability predicted by standard α-models.

  12. Formation of Black Hole Low-mass X-Ray Binaries in Hierarchical Triple Systems

    NASA Astrophysics Data System (ADS)

    Naoz, Smadar; Fragos, Tassos; Geller, Aaron; Stephan, Alexander P.; Rasio, Frederic A.

    2016-05-01

    The formation of black hole (BH) low-mass X-ray binaries (LMXB) poses a theoretical challenge, as low-mass companions are not expected to survive the common-envelope scenario with the BH progenitor. Here we propose a formation mechanism that skips the common-envelope scenario and relies on triple-body dynamics. We study the evolution of hierarchical triples following the secular dynamical evolution up to the octupole-level of approximation, including general relativity, tidal effects, and post-main-sequence evolution such as mass loss, changes to stellar radii, and supernovae. During the dynamical evolution of the triple system the “eccentric Kozai-Lidov” mechanism can cause large eccentricity excitations in the LMXB progenitor, resulting in three main BH-LMXB formation channels. Here we define BH-LMXB candidates as systems where the inner BH-companion star crosses its Roche limit. In the “eccentric” channel (˜81% of the LMXBs in our simulations) the donor star crosses its Roche limit during an extreme eccentricity excitation while still on a wide orbit. Second, we find a “giant” LMXB channel (˜11%), where a system undergoes only moderate eccentricity excitations but the donor star fills its Roche-lobe after evolving toward the giant branch. Third, we identify a “classical” channel (˜8%), where tidal forces and magnetic braking shrink and circularize the orbit to short periods, triggering mass-transfer. Finally, for the giant channel we predict an eccentric (˜0.3-0.6) preferably inclined (˜40°, ˜140°) tertiary, typically on a wide enough orbit (˜104 au) to potentially become unbound later in the triple evolution. While this initial study considers only one representative system and neglects BH natal kicks, we expect our scenario to apply across a broad region of parameter space for triple-star systems.

  13. Chandra Characterization of X-Ray Emission in the Young F-Star Binary System HD 113766

    NASA Astrophysics Data System (ADS)

    Lisse, C. M.; Christian, D. J.; Wolk, S. J.; Günther, H. M.; Chen, C. H.; Grady, C. A.

    2017-02-01

    Using Chandra, we have obtained imaging X-ray spectroscopy of the 10–16 Myr old F-star binary HD 113766. We individually resolve the 1.″4 separation binary components for the first time in the X-ray and find a total 0.3–2.0 keV luminosity of 2.2 × 1029 erg s‑1, consistent with previous RASS estimates. We find emission from the easternmost, infrared-bright, dusty member HD 113766A to be only ∼10% that of the western, infrared-faint member HD 113766B. There is no evidence for a 3rd late-type stellar or substellar member of HD 113766 with Lx > 6 × 1025 erg s‑1 within 2‧ of the binary pair. The ratio of the two stars’ X-ray luminosity is consistent with their assignments as F2V and F6V by Pecaut et al. The emission is soft for both stars, kTApec = 0.30–0.50 keV, suggesting X-rays produced by stellar rotation and/or convection in young dynamos, but not accretion or outflow shocks, which we rule out. A possible 2.8 ± 0.15 (2σ) hr modulation in the HD 113766B X-ray emission is seen, but at very low confidence and of unknown provenance. Stellar wind drag models corresponding to Lx ∼ 2 × 1029 erg s‑1 argue for a 1 mm dust particle lifetime around HD 113766B of only ∼90,0000 years, suggesting that dust around HD 113766B is quickly removed, whereas 1 mm sized dust around HD 113766A can survive for >1.5 × 106 years. At 1028–1029 erg s‑1 X-ray luminosity, astrobiologically important effects, like dust warming and X-ray photolytic organic synthesis, are likely for any circumstellar material in the HD 113766 systems.

  14. Estimation of the accuracy of methods for determining component masses for low-mass X-ray binary systems

    NASA Astrophysics Data System (ADS)

    Antokhina, E. A.; Petrov, V. S.; Cherepashchuk, A. M.

    2017-01-01

    Modern modeling of the population of low-mass X-ray binary systems containing black holes applying standard assumptions leads to a lack of agreement between the modeled and observed mass distributions for the optical components, with the observed masses being lower. This makes the task of estimating the systematic errors in the derived component masses due to imperfect models relevant. To estimate the influence of systematic errors in the derived masses of stars in X-ray binary systems, we considered two approximations for the tidally deformed star in a Roche model. Approximating the star as a sphere with a volume equal to that of the Roche lobe leads to slight overestimation of the equatorial rotational velocity V rot sin i, and hence to slight underestimation of the mass ratio q = M x / M v . Approximating the star as a flat, circular disk with constant local line profiles and a linear limb-darkening law (a classical rotational broadeningmodel) is an appreciably cruder approach, and leads to overestimation of V rot sin i by about 20%. In the case of high values of q = M x / M v , this approximation leads to substantial underestimation of the mass ratio q, which can reach several tens of percent. The mass of the optical star is overestimated by a factor of 1.5 in this case, while the mass of the black hole is changed only slightly. Since most estimates of component mass ratios for X-ray binary systems are carried out using a classical rotational broadening model for the lines, this leads to the need for appreciable corrections to (reductions of) previously published masses for the optical stars, which enhances the contradiction with the standard evolutionary scenario for low-mass X-ray binaries containing black holes.

  15. Optical and near-infrared photometric monitoring of the transient X-ray binary A0538-66 with REM

    NASA Astrophysics Data System (ADS)

    Ducci, L.; Covino, S.; Doroshenko, V.; Mereghetti, S.; Santangelo, A.; Sasaki, M.

    2016-11-01

    The transient Be/X-ray binary A0538-66 shows peculiar X-ray and optical variability. Despite numerous studies, the intrinsic properties underlying its anomalous behaviour remain poorly understood. Since September 2014 we have conducted the first quasi-simultaneous, optical and near-infrared photometric monitoring of A0538-66 in seven filters with the Rapid Eye Mount (REM) telescope to understand the properties of this binary system. We found that the REM light curves show fast flares lasting one or two days that repeat almost regularly every 16.6 d, which is the orbital period of the neutron star. If the optical flares are powered by X-ray outbursts through photon reprocessing, the REM light curves indicate that A0538-66 is still active in X-rays; bright X-ray flares (Lx ≳ 1037 erg s-1) could be observable during the periastron passages. The REM light curves show a long-term variability that is especially pronounced in the g-band and decreases with increasing wavelength until it no longer appears in the near-infrared light curves. In addition, A0538-66 is fainter with respect to previous optical observations, and this is likely because of the higher absorption of the stellar radiation of a denser circumstellar disc. On the basis of the current models, we interpret these observational results with a circumstellar disc around the Be star observed nearly edge-on during a partial depletion phase. The REM light curves also show short-term variability on timescales of 1 day, which is possibly indicative of perturbations in the density distribution of the circumstellar disc caused by the tidal interaction with the neutron star.

  16. Discovery of a variable X-ray counterpart to HESS J1832-093: a new gamma-ray binary?

    NASA Astrophysics Data System (ADS)

    Eger, P.; Laffon, H.; Bordas, P.; de Oña Whilhelmi, E.; Hinton, J.; Pühlhofer, G.

    2016-04-01

    The TeV gamma-ray point source HESS J1832-093 remains unidentified despite extensive multiwavelength studies. The gamma-ray emission could originate in a very compact pulsar wind nebula or an X-ray binary system composed of the X-ray source XMMU J183245-0921539, and a companion star (2MASS J18324516-0921545). To unveil the nature of XMMU J183245-0921539 and its relation to HESS J1832-093, we performed deeper follow-up observations in X-rays with Chandra and Swift to improve source localization and to investigate time variability. We observed an increase of the X-ray flux by a factor of ˜6 in the Chandra data compared to previous observations. The source is point-like for Chandra and its updated position is only 0.3 arcsec offset from 2MASS J18324516-0921545, confirming the association with this infrared source. Subsequent Swift target of opportunity observations resulted in a lower flux, again compatible with the one previously measured with XMM-Newton, indicating a variability time-scale of the order of two months or shorter. The now-established association of XMMU J183245-0921539 and 2MASS J18324516-0921545, and the observed variability in X-rays are strong evidence for binary nature of HESS J1832-093. Furthermore, observations to characterize the optical counterpart as well as to search for orbital periodicity are needed to confirm this scenario.

  17. X-ray emission from the flare star binary Gliese 867 A

    NASA Technical Reports Server (NTRS)

    Agrawal, P. C.

    1988-01-01

    Coronal X-ray emission from the BY Draconis type dMe flare star G867 A was observed on three successive days in May 1980 with the Imaging Proportional Counter on the Einstein Observatory. A 40-percent decrease in the quiescent state X-ray intensity of the star was detected over a three-day period. It is suggested that this slow quiescent state X-ray intensity variation may be the X-ray analogue of the BY Draconis variability observed in the optical band and may be explained by the star spot model. The energy spectra of the star were obtained for the three days and are best fitted by a two-temperature Raymond-Smith thermal model. There is some indication of spectral variations in the low temperature component. Implications of these results are briefly discussed.

  18. X-ray and optical spectroscopy of the massive young open cluster IC 1805

    NASA Astrophysics Data System (ADS)

    Rauw, G.; Nazé, Y.

    2016-10-01

    Context. Very young open clusters are ideal places to study the X-ray properties of a homogeneous population of early-type stars. In this respect, the IC 1805 open cluster is very interesting as it hosts the O4 If+ star HD 15570 thought to be in an evolutionary stage intermediate between a normal O-star and a Wolf-Rayet star. Aims: Such a star could provide a test for theoretical models aiming at explaining the empirical scaling relation between the X-ray and bolometric luminosities of O-type stars. Methods: We have observed IC 1805 with XMM-Newton and further collected optical spectroscopy of some of the O-star members of the cluster. Results: The optical spectra allow us to revisit the orbital solutions of BD+60° 497 and HD 15558, and provide the first evidence of binarity for BD+60° 498. X-ray emission from colliding winds does not appear to play an important role among the O-stars of IC 1805. Notably, the X-ray fluxes do not vary significantly between archival X-ray observations and our XMM-Newton pointing. The very fast rotator BD+60° 513, and to a lesser extent the O4 If+ star HD 15570 appear somewhat underluminous. Whilst the underluminosity of HD 15570 is only marginally significant, its amplitude is found to be compatible with theoretical expectations based on its stellar and wind properties. A number of other X-ray sources are detected in the field, and the brightest objects, many of which are likely low-mass pre-main sequence stars, are analyzed in detail. Based on observations collected with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and the USA (NASA), and with the TIGRE telescope (La Luz, Mexico).Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A82

  19. Radio luminosity upper limits of the transient neutron star low-mass X-ray binary GRO J1744-28

    NASA Astrophysics Data System (ADS)

    Russell, Thomas; Degenaar, Nathalie; Miller-Jones, James; Tudor, Vlad

    2017-02-01

    Following the new outburst of the Galactic neutron star low-mass X-ray binary and 2.1 Hz X-ray pulsar GRO J1744-28 (ATels #10073, #10079), we performed target of opportunity observations of this source with the Australia Telescope Compact Array (ATCA).

  20. Studies of the Origin of High-frequency Quasi-periodic Oscillations of Mass-accreting Black Holes in X-Ray Binaries with Next-generation X-Ray Telescopes

    NASA Astrophysics Data System (ADS)

    Beheshtipour, Banafsheh; Hoormann, Janie K.; Krawczynski, Henric

    2016-08-01

    Observations with RXTE (Rossi X-ray Timing Explorer) revealed the presence of high-frequency quasi-periodic oscillations (HFQPOs) of the X-ray flux from several accreting stellar-mass black holes. HFQPOs (and their counterparts at lower frequencies) may allow us to study general relativity in the regime of strong gravity. However, the observational evidence today does not yet allow us to distinguish between different HFQPO models. In this paper we use a general-relativistic ray-tracing code to investigate X-ray timing spectroscopy and polarization properties of HFQPOs in the orbiting Hotspot model. We study observational signatures for the particular case of the 166 Hz quasi-periodic oscillation (QPO) in the galactic binary GRS 1915+105. We conclude with a discussion of the observability of spectral signatures with a timing-spectroscopy experiment such as the LOFT (Large Observatory for X-ray Timing) and polarization signatures with space-borne X-ray polarimeters such as IXPE (Imaging X-ray Polarimetry Explorer), PolSTAR (Polarization Spectroscopic Telescope Array), PRAXyS(Polarimetry of Relativistic X-ray Sources), or XIPE (X-ray Imaging Polarimetry Explorer). A mission with high count rate such as LOFT would make it possible to get a QPO phase for each photon, enabling the study of the QPO-phase-resolved spectral shape and the correlation between this and the flux level. Owing to the short periods of the HFQPOs, first-generation X-ray polarimeters would not be able to assign a QPO phase to each photon. The study of QPO-phase-resolved polarization energy spectra would thus require simultaneous observations with a first-generation X-ray polarimeter and a LOFT-type mission.

  1. Revelations of X-ray spectral analysis of the enigmatic black hole binary GRS 1915+105

    NASA Astrophysics Data System (ADS)

    Peris, Charith; Remillard, Ronald A.; Steiner, James; Dil Vrtilek, Saeqa; Varniere, Peggy; Rodriguez, Jerome; Pooley, Guy

    2016-01-01

    Of the black hole binaries discovered thus far, GRS 1915+105 stands out as an exceptional source primarily due to its wild X-ray variability, the diversity of which has not been replicated in any other stellar-mass black hole. Although extreme variability is commonplace in its light-curve, about half of the observations of GRS1915+105 show fairly steady X-ray intensity. We report on the X-ray spectral behavior within these steady observations. Our work is based on a vast RXTE/PCA data set obtained on GRS 1915+105 during the course of its entire mission and 10 years of radio data from the Ryle Telescope, which overlap the X-ray data. We find that the steady observations within the X-ray data set naturally separate into two regions in a color-color diagram, which we refer to as steady-soft and steady-hard. GRS 1915+105 displays significant curvature in the Comptonization component within the PCA band pass suggesting significantly heating from a hot disk present in all states. A new Comptonization model 'simplcut' was developed in order to model this curvature to best effect. A majority of the steady-soft observations display a roughly constant inner radius; remarkably reminiscent of canonical soft state black hole binaries. In contrast, the steady-hard observations display a growing disk truncation that is correlated to the mass accretion rate through the disk, which suggests a magnetically truncated disk. A comparison of X-ray model parameters to the canonical state definitions show that almost all steady-soft observations match the criteria of either thermal or steep power law state, while the thermal state observations dominate the constant radius branch. A large portion (80%) of the steady-hard observations matches the hard state criteria when the disk fraction constraint is neglected. These results suggest that within the complexity of this source is a simpler underlying basis of states, which map to those observed in canonical black hole binaries. When

  2. X-RAY EMISSION FROM THE DOUBLE-BINARY OB-STAR SYSTEM QZ CAR (HD 93206)

    SciTech Connect

    Parkin, E. R.; Naze, Y.; Rauw, G.; Broos, P. S.; Townsley, L. K.; Pittard, J. M.; Moffat, A. F. J.; Oskinova, L. M.; Waldron, W. L.

    2011-05-01

    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{sub A} = 21 days) and B (O8 III+o9 v, P{sub 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 {approx_equal} 0.2, 0.7, and 2 keV, respectively, and a circumstellar absorption of {approx_equal}0.2 x 10{sup 22} cm{sup -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 {approx_equal}7 x 10{sup -13} erg s{sup -1} cm{sup -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.

  3. Structure and intermolecular interactions in selected binary solutions studied by X-ray methods

    NASA Astrophysics Data System (ADS)

    Drozdowski, Henryk; Romaniuk, Anna; Błaszczak, Zdzisław

    2013-12-01

    The results of X-ray structural studies of liquid chloroanisole C6H4OCH3Cl and 10% solutions of chloroanisole in 1,4-dimethylbenzene C8H10 are presented. It is the first paper on an X-ray diffraction study of the liquid solutions of chloroanisole. The X-ray measurements were made at 293 K for the scattering angle range 2Θ varying from 6° to 120°. Averaged scattered X-ray angular distributions I¯(S) were determined. The angular distributions of the intensity of X-ray scattered by 10% solutions of chloroanisole in 1,4-dimethylbenzene were compared to the angular distributions obtained for liquid ortho-, meta- and para-chloroanisole. The differential radial distribution functions of electron density 4πr∑j,knK[ρk(r)-ρ0] were numerically found using the Fourier analysis from a modified Warren, Krutter and Morningstar equation. To the maxima of DRDFs, interatomic and intermolecular distances were assigned. The use of short-wave radiation from an X-ray tube with a molybdenum anode permitted determination of the spheres of intermolecular ordering in the studied liquids and their solutions. The experimental results were used to plot models of the most highly probable mutual disposition of the molecules in liquid chloroanisole and their solutions. The benzene rings of two molecules are situated in parallel plane what results in antiparallel setting of the dipole moments of the chloroanisole molecules. X-ray structural analysis was applied to determine the packing coefficients of chloroanisole molecules. The results obtained in this paper confirm the specific structural properties of the solutions studied.

  4. Highlighting XMM-Newton's Role in Time Domain Studies of Neutron Star and Black Hole X-ray binaries in Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Leiter, K.; Kadler, M.; Wilms, J.; Braatz, J.; Grossberger, C.; Krauß, F.; Kreikenbohm, A.; Langejahn, M.; Litzinger, E.; Markowitz, A.

    2015-09-01

    XMM-Newton's combination of large effective area, superior event timing, and wide field imaging have provided a powerful capability for time-domain studies of nearby X-ray binary populations. In its first 15 years XMM has accomplished groundbreaking monitoring surveys for X-ray binaries; complemented by RXTE, Chandra, and Nustar. Over the next decade XMM's capabilities will complement a new generation of missions including Astrosat, Hitomi, and NICER. This paper highlights the role of XMM-Newton in combination with other missions, in exploring the HMXB populations of the Small Magellanic Cloud and IC 10. Both are nearby dwarf starburst galaxies, yet their ages and evolutionary scenarios are very different, the consequences of which have led to contrasting X-ray binary populations. In the SMC the definitive sample of X-ray binary pulsars assembled by RXTE is revealing fundamental accretion physics when probed by XMM. Finding and characterizing IC 10's youthful X-ray binaries required the combination of XMM together with Chandra and Nustar. Key results include the revelatory finding of an X-ray irradiated wind masking the mass-function in the WR+BH binary X-1 and the measurement of the BH's spin. Such studies have wide relevance to stellar/galactic evolution, implications for black hole masses and formation channels for BH+BH binaries.

  5. Highlighting XMM-Newton's Role in Time Domain Studies of Neutron Star and Black Hole X-ray binaries in Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Laycock, S.; Yang, J.; Cappallo, R.; Christodoulou, D.; Steiner, J.

    2016-09-01

    XMM-Newton's combination of large effective area, superior event timing, and wide field imaging have provided a powerful capability for time-domain studies of nearby X-ray binary populations. In its first 15 years XMM has accomplished groundbreaking monitoring surveys for X-ray binaries; complemented by RXTE, Chandra, and Nustar. Over the next decade XMM's capabilities will complement a new generation of missions including Astrosat, Hitomi, and NICER. This paper highlights the role of XMM-Newton in combination with other missions, in exploring the HMXB populations of the Small Magellanic Cloud and IC 10. Both are nearby dwarf starburst galaxies, yet their ages and evolutionary scenarios are very different, the consequences of which have led to contrasting X-ray binary populations. In the SMC the definitive sample of X-ray binary pulsars assembled by RXTE is revealing fundamental accretion physics when probed by XMM. Finding and characterizing IC 10's youthful X-ray binaries required the combination of XMM together with Chandra and Nustar. Key results include the revelatory finding of an X-ray irradiated wind masking the mass-function in the WR+BH binary X-1 and the measurement of the BH's spin. Such studies have wide relevance to stellar/galactic evolution, implications for black hole masses and formation channels for BH+BH binaries.

  6. The 5 Hour Pulse Period and Broadband Spectrum of the Symbiotic X-Ray Binary 3A 1954+319

    NASA Technical Reports Server (NTRS)

    Marcu, Diana M.; Fuerst, Felix; Pottschmidt, Katja; Grinberg, Victoria; Miller, Sebstian; Wilms, Joern; Postnov, Konstantin A.; Corbet, Robin H. D.; Markwardt, Craig B.; Cadolle Bel, Marion

    2011-01-01

    We present an analysis of the highly variable accreting X-ray pulsar 3A 1954+319 using 2005-2009 monitoring data obtained with INTEGRAL and Swift. This considerably extends the pulse period history and covers flaring episodes in 2005 and 2008. In 2006 the source was identified as one of only a few known symbiotic X-ray binaries, Le" systems composed of a neutron star accreting from the inhomogeneous medium around an M-giant star. The extremely long pulse period of approximately 5.3 h is directly visible in the 2008 INTEGRAL-ISGRI outburst light curve. The pulse profile is double peaked and not significantly energy dependent. During the outburst a strong spin-up of -1.8 x 10(exp -4) h h(exp -1) occurred. Between 2005 and 2008 a long term spin-down trend of 2.1 x 10(exp -5) h h(exp -1) was observed for the first time for this source. The 3-80 keV pulse peak spectrum of 3A 1954+319 during the 2008 flare could be well described by a thermal Comptonization model. We interpret the results within the framework of a recently developed quasi-spherical accretion model for symbiotic X-ray binaries.

  7. A jet emission model to probe the dynamics of accretion and ejection coupling in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Malzac, Julien

    2016-07-01

    Compact jets are probably the most common form of jets in X-ray binaries and Active Galactic Nuclei. They seem to be present in all sources in the so-called hard X-ray spectral state. They are characterised by a nearly flat Spectral Energy Distribution (SED) extending from the radio to the infrared bands. This emission is usually interpreted as partially self absorbed synchrotron emission from relativistic leptons accelerated in the jet. The observed flat spectral shape requires energy dissipation and acceleration of particules over a wide range of distances along the jet. This distributed energy dissipation is likely to be powered by internal shocks caused by fluctuations of the outflow velocity. I will discuss such an internal shock model in the context of black hole binaries. I will show that internal shocks can produce the observed SEDs and also predict a strong, wavelength dependent, variability that resembles the observed one. The assumed velocity fluctuations of the jet must originate in the accretion flow. The model thus predicts a strong connection between the observable properties of the jet in the radio to IR bands, and the variability of the accretion flow as observed in X-rays. If the model is correct, this offers a unique possibility to probe the dynamics of the coupled accretion and ejection processes leading to the formation of compact jets.

  8. ON THE ORIGIN OF THE METALLICITY DEPENDENCE IN DYNAMICALLY FORMED EXTRAGALACTIC LOW-MASS X-RAY BINARIES

    SciTech Connect

    Ivanova, N.; Avendano Nandez, J. L.; Sivakoff, G. R.; Fragos, T.; Kim, D.-W.; Fabbiano, G.; Lombardi, J. C.; Voss, R.

    2012-12-01

    Globular clusters (GCs) effectively produce dynamically formed low-mass X-ray binaries (LMXBs). Observers detect {approx}100 times more LMXBs per stellar mass in GCs compared to stars in the fields of galaxies. Observationally, metal-rich GCs are about three times more likely to contain an X-ray source than their metal-poor counterparts. Recent observations have shown that this ratio holds in extragalactic GCs for all bright X-ray sources with L{sub X} between 2 Multiplication-Sign 10{sup 37} and 5 Multiplication-Sign 10{sup 38} erg s{sup -1}. In this Letter, we propose that the observed metallicity dependence of LMXBs in extragalactic GCs can be explained by the differences in the number densities and average masses of red giants in populations of different metallicities. Red giants serve as seeds for the dynamical production of bright LMXBs via two channels-binary exchanges and physical collisions-and the increase of the number densities and masses of red giants boost LMXB production, leading to the observed difference. We also discuss a possible effect of the age difference in stellar populations of different metallicities.

  9. Discovery of a cyclotron absorption line in the spectrum of the binary X-ray pulsar 4U 1538 - 52 observed by Ginga

    NASA Technical Reports Server (NTRS)

    Clark, George W.; Woo, Jonathan W.; Nagase, Fumiaki; Makishima, Kazuo; Sakao, Taro

    1990-01-01

    A cyclotron absorption line near 20 keV has been found in the spectrum of the massive eclipsing binary X-ray pulsar 4U 1538 - 52 in observations with the Ginga observatory. The line is detected throughout the 529 s pulse cycle with a variable equivalent width that has its maximum value during the smaller peak of the two-peak pulse profile. It is found that the profile of the pulse and the phase-dependence of the cyclotron line can be explained qualitatively by a pulsar model based on recent theoretical results on the properties of pencil beams emitted by accretion-heated slabs of magnetized plasma at the magnetic poles of a neutron star. The indicated field at the surface of the neutron star is 1.7 (1 + z) x 10 to the 12th G, where z is the gravitational redshift.

  10. Optical orbit of the X-ray pulsar binary 0535 - 668 (= A0538 - 66)

    SciTech Connect

    Hutchings, J.B.; Crampton, D.; Cowley, A.P.; Olszewski, E.; Thompson, I.B.; Suntzeff, N.

    1985-05-01

    Spectroscopic data are presented from the optical primary of the LMC X-ray source 0535 - 668 during its optical low state. From these data the star appears as a normal B1 star, slightly evolved off the main sequence. Adopting the X-ray outburst period of 16.65 days, radial velocities indicate an orbit with a high eccentricity, and periastron passage very close to the X-ray flux peak. Probable masses are normal for the primary and the pulsar. At periastron, the center of mass separation is less than the primary-star diameter, and during optical outburst the photosphere is larger than the minimum separation. Orbital parameters and implied quantities are discussed. 18 references.

  11. The Motif of Globular Clusters and Low Mass X-ray Binaries in Ellipticals: a Tale of Three Galaxies

    NASA Astrophysics Data System (ADS)

    D'Abrusco, Raffaele; Fabbiano, Giuseppina; Mineo, Stefano; Strader, Jay; Fragos, Tassos; Kim, Dong-Woo; Luo, Bin; Zezas, Andreas

    2014-06-01

    I will discuss significant inhomogeneities in the projected two-dimensional spatial distributions of Globular Clusters and Low Mass X-Ray Binaries observed in three elliptical galaxies with extensive spatial coverage in the optical and X-ray: NGC4261, NGC4649 and NGC4278. The spatial structures in the distributions of GCs and LMXBs have been detected with a new method based on the K-Nearest Neighbor density estimator of Dressler (1980), complemented by MonteCarlo simulations to establish the statistical significance of the results. I will present the spatial structures as a function of the color and luminosity of the GCs, and will compare their shape and significance with the spatial distribution of field LMXBs. I will then examine the nature of these structures in the context of the evolution history of the host galaxies.

  12. A RADIO-SELECTED BLACK HOLE X-RAY BINARY CANDIDATE IN THE MILKY WAY GLOBULAR CLUSTER M62

    SciTech Connect

    Chomiuk, Laura; Ransom, Scott; Strader, Jay; Maccarone, Thomas J.; Miller-Jones, James C. A.; Heinke, Craig; Noyola, Eva; Seth, Anil C.

    2013-11-01

    We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we call M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl G. Jansky Very Large Array. M62-VLA1 is a faint source with a flux density of 18.7 ± 1.9 μJy at 6.2 GHz and a flat radio spectrum (α = –0.24 ± 0.42, for S{sub ν} = ν{sup α}). M62 is the second Milky Way cluster with a candidate stellar-mass black hole; unlike the two candidate black holes previously found in the cluster M22, M62-VLA1 is associated with a Chandra X-ray source, supporting its identification as a black hole X-ray binary. Measurements of its radio and X-ray luminosity, while not simultaneous, place M62-VLA1 squarely on the well-established radio-X-ray correlation for stellar-mass black holes. In archival Hubble Space Telescope imaging, M62-VLA1 is coincident with a star near the lower red giant branch. This possible optical counterpart shows a blue excess, Hα emission, and optical variability. The radio, X-ray, and optical properties of M62-VLA1 are very similar to those for V404 Cyg, one of the best-studied quiescent stellar-mass black holes. We cannot yet rule out alternative scenarios for the radio source, such as a flaring neutron star or background galaxy; future observations are necessary to determine whether M62-VLA1 is indeed an accreting stellar-mass black hole.

  13. Massive Submandibular Sialolith: Complete Radiographic Registration and Biochemical Analysis through X-Ray Diffraction

    PubMed Central

    de Carvalho Mattos, Mayara Jessica; Ferrari, Francine; dos Reis Neto, José Manoel; Carta Gambus, Luiz Carlos; Couto Souza, Paulo Henrique; Berti-Couto, Soraya de Azambuja

    2014-01-01

    Sialolithiasis is a pathologic condition that affects 60 million people per year, which is caused by the presence of calcified structures, named sialoliths, inside the salivary glands and their salivary ducts. Despite the large incidence of sialolithiasis, its etiology is still unknown. In the present case report, a 47-year-old female patient, presenting with local pain and hampered mouth opening, underwent a surgical approach for the removal of a 20 mm sialolith, which was further analyzed through X-ray diffraction. In parallel, a radiographic registration of 8 years, covering all the period for sialolith formation, is presented along the case report. PMID:25258693

  14. Discovery of a Be/X-ray pulsar binary and associated supernova remnant in the Wing of the Small Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Hénault-Brunet, V.; Oskinova, L. M.; Guerrero, M. A.; Sun, W.; Chu, Y.-H.; Evans, C. J.; Gallagher, J. S., III; Gruendl, R. A.; Reyes-Iturbide, J.

    2012-02-01

    We report on a new Be/X-ray pulsar binary located in the Wing of the Small Magellanic Cloud (SMC). The strong pulsed X-ray source was discovered with the Chandra and XMM-Newton X-ray observatories. The X-ray pulse period of 1062 s is consistently determined from both Chandra and XMM-Newton observations, revealing one of the slowest rotating X-ray pulsars known in the SMC. The optical counterpart of the X-ray source is the emission-line star 2dFS 3831. Its B0-0.5(III)e+ spectral type is determined from VLT-FLAMES and 2dF optical spectroscopy, establishing the system as a Be/X-ray binary (Be-XRB). The hard X-ray spectrum is well fitted by a power law with additional thermal and blackbody components, the latter reminiscent of persistent Be-XRBs. This system is the first evidence of a recent supernova in the low-density surroundings of NGC 602. We detect a shell nebula around 2dFS 3831 in Hα and [O III] images and conclude that it is most likely a supernova remnant. If it is linked to the supernova explosion that created this new X-ray pulsar, its kinematic age of (2-4) × 104 yr provides a constraint on the age of the pulsar.

  15. Multi-wavelength properties of IGR J05007-7047 (LXP 38.55) and identification as a Be X-ray binary pulsar in the LMC

    NASA Astrophysics Data System (ADS)

    Vasilopoulos, G.; Haberl, F.; Delvaux, C.; Sturm, R.; Udalski, A.

    2016-09-01

    We report on the results of a ˜40-d multi-wavelength monitoring of the Be X-ray binary system IGR J05007-7047 (LXP 38.55). During that period the system was monitored in the X-rays using the Swift telescope and in the optical with multiple instruments. When the X-ray luminosity exceeded 1036 erg s-1 we triggered an XMM-Newton ToO observation. Timing analysis of the photon events collected during the XMM-Newton observation reveals coherent X-ray pulsations with a period of 38.551(3) s (1σ), making it the 17th known high-mass X-ray binary pulsar in the LMC. During the outburst, the X-ray spectrum is fitted best with a model composed of an absorbed power law (Γ = 0.63) plus a high-temperature blackbody (kT ˜2 keV) component. By analysing ˜12 yr of available OGLE optical data we derived a 30.776(5) d optical period, confirming the previously reported X-ray period of the system as its orbital period. During our X-ray monitoring the system showed limited optical variability while its IR flux varied in phase with the X-ray luminosity, which implies the presence of a disc-like component adding cooler light to the spectral energy distribution of the system.

  16. LIMITS ON [O III] 5007 EMISSION FROM NGC 4472'S GLOBULAR CLUSTERS: CONSTRAINTS ON PLANETARY NEBULAE AND ULTRALUMINOUS BLACK HOLE X-RAY BINARIES IN GLOBULAR CLUSTERS

    SciTech Connect

    Peacock, Mark B.; Zepf, Stephen E.; Maccarone, Thomas J.

    2012-06-20

    We have searched for [O III] 5007 emission in high-resolution spectroscopic data from FLAMES/GIRAFFE Very Large Telescope observations of 174 massive globular clusters (GCs) in NGC 4472. No planetary nebulae (PNe) are observed in these clusters, constraining the number of PNe per bolometric luminosity, {alpha} < 0.8 Multiplication-Sign 10{sup -7} PN/L{sub Sun }. This is significantly lower than the rate predicted from stellar evolution, if all stars produce PNe. Comparing our results to populations of PNe in galaxies, we find most galaxies have a higher {alpha} than these GCs (more PNe per bolometric luminosity-though some massive early-type galaxies do have similarly low {alpha}). The low {alpha} required in these GCs suggests that the number of PNe per bolometric luminosity does not increase strongly with decreasing mass or metallicity of the stellar population. We find no evidence for correlations between the presence of known GC PNe and either the presence of low-mass X-ray binaries (LMXBs) or the stellar interaction rates in the GCs. This, and the low {alpha} observed, suggests that the formation of PNe may not be enhanced in tight binary systems. These data do identify one [O III] emission feature, this is the (previously published) broad [O III] emission from the cluster RZ 2109. This emission is thought to originate from the LMXB in this cluster, which is accreting at super-Eddington rates. The absence of any similar [O III] emission from the other clusters favors the hypothesis that this source is a black hole LMXB, rather than a neutron star LMXB with significant geometric beaming of its X-ray emission.

  17. Probabilistic HR Diagrams: A New Infrared and X-ray Chronometer for Very Young, Massive Stellar Clusters and Associations

    NASA Astrophysics Data System (ADS)

    Maldonado, Jessica; Povich, Matthew S.

    2016-01-01

    We present a novel method for constraining the duration of star formation in very young, massive star-forming regions. Constraints on stellar population ages are derived from probabilistic HR diagrams (pHRDs) generated by fitting stellar model spectra to the infrared (IR) spectral energy distributions (SEDs) of Herbig Ae/Be stars and their less-evolved, pre-main sequence progenitors. Stellar samples for the pHRDs are selected based on the detection of X-ray emission associated with the IR source, and the lack of detectible IR excess emission at wavelengths ≤4.5 µm. The SED model fits were used to create two-dimensional probability distributions of the stellar parameters, specifically bolometric luminosity versus temperature and mass versus evolutionary age. We present first results from the pHRD analysis of the relatively evolved Carina Nebula and the unevolved M17 SWex infrared dark cloud, which reveal the expected, strikingly different star formation durations between these two regions. In the future, we will apply this method to analyze available X-ray and IR data from the MYStIX project on other Galactic massive star forming regions within 3 kpc of the Sun.

  18. Massive binary stars as a probe of massive star formation

    NASA Astrophysics Data System (ADS)

    Kiminki, Daniel C.

    2010-10-01

    Massive stars are among the largest and most influential objects we know of on a sub-galactic scale. Binary systems, composed of at least one of these stars, may be responsible for several types of phenomena, including type Ib/c supernovae, short and long gamma ray bursts, high-velocity runaway O and B-type stars, and the density of the parent star clusters. Our understanding of these stars has met with limited success, especially in the area of their formation. Current formation theories rely on the accumulated statistics of massive binary systems that are limited because of their sample size or the inhomogeneous environments from which the statistics are collected. The purpose of this work is to provide a higher-level analysis of close massive binary characteristics using the radial velocity information of 113 massive stars (B3 and earlier) and binary orbital properties for the 19 known close massive binaries in the Cygnus OB2 Association. This work provides an analysis using the largest amount of massive star and binary information ever compiled for an O-star rich cluster like Cygnus OB2, and compliments other O-star binary studies such as NGC 6231, NGC 2244, and NGC 6611. I first report the discovery of 73 new O or B-type stars and 13 new massive binaries by this survey. This work involved the use of 75 successful nights of spectroscopic observation at the Wyoming Infrared Observatory in addition to observations obtained using the Hydra multi-object spectrograph at WIYN, the HIRES echelle spectrograph at KECK, and the Hamilton spectrograph at LICK. I use these data to estimate the spectrophotometric distance to the cluster and to measure the mean systemic velocity and the one-sided velocity dispersion of the cluster. Finally, I compare these data to a series of Monte Carlo models, the results of which indicate that the binary fraction of the cluster is 57 +/- 5% and that the indices for the power law distributions, describing the log of the periods, mass

  19. A Massive X-ray Outflow From The Quasar PDS 456

    NASA Technical Reports Server (NTRS)

    Reeves, J. N.; O'Brien, P. T.; Ward, M. J.

    2003-01-01

    We report on XMM-Newton spectroscopic observations of the luminous, radio-quiet quasar PDS 456. The hard X-ray spectrum of PDS 456 shows a deep absorption trough (constituting 50% of the continuum) at energies above 7 keV in the quasar rest frame, which can be attributed to a series of blue-shifted K-shell absorption edges due to highly ionized iron. The higher resolution soft X-ray grating RGS spectrum exhibits a broad absorption line feature near 1 keV, which can be modeled by a blend of L-shell transitions from highly ionized iron (Fe XVII - XXIV). An extreme outflow velocity of approx. 50000 km/s is required to model the K and L shell iron absorption present in the XMM-Newton data. Overall, a large column density (N(sub H) = 5 x 10(exp 23)/sq cm) of highly ionized gas (log xi = 2.5) is required in PDS 456. A large mass outflow rate of approx. 10 solar mass/year (assuming a conservative outflow covering factor of 0.1 steradian) is derived, which is of the same order as the overall mass accretion rate in PDS 456. This represents a substantial fraction (approx. 10%) of the quasar energy budget, whilst the large column and outflow velocity place PDS 456 towards the extreme end of the broad absorption line quasar population.

  20. An X-ray/optical study of the geometry and dynamics of MACS J0140.0-0555, a massive post-collision cluster merger

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting; Ebeling, Harald; Richard, Johan

    2012-11-01

    We investigate the physical properties, geometry and dynamics of the massive cluster merger MACS J0140.0-0555 (z = 0.451) using X-ray and optical diagnostics. Featuring two galaxy overdensities separated by about 250 kpc in projection on the sky, and a single peak in the X-ray surface brightness distribution located between them, MACS J0140.0-0555 shows the tell-tale X-ray/optical morphology of a binary, post-collision merger. Our spectral analysis of the X-ray emission, as measured by our Chandra ACIS-I observation of the system, finds the intra-cluster medium to be close to isothermal (˜8.5 keV) with no clear signs of cool cores or shock fronts. Spectroscopic follow-up of galaxies in the field of MACS J0140.0-0555 yields a velocity dispersion of 875-100+70 km s-1 (nz = 66) and no significant evidence of bimodality or substructure along the line of sight. In addition, the difference in radial velocity between the brightest cluster galaxies of the two sub-clusters of 144 ± 25 km s-1 is small compared to typical collision velocities of several 1000 km s-1. A strongly lensed background galaxy at z = 0.873 (which features variable X-ray emission from an active nucleus) provides the main constraint on the mass distribution of the system. We measure M(<75 kpc) = (5.6 ± 0.5) × 1013 M⊙ for the north-western cluster component and a much less certain estimate of (1.5-3) × 1013 M⊙ for the south-eastern sub-cluster. These values are in good agreement with our X-ray mass estimates which yield a total mass of MACS J0140.0-0555 of M(X-ray properties of MACS J0140.0-0555 are consistent with a well-advanced head-on merger proceeding along an axis close to the plane of the sky, the degeneracy between Hubble flow and peculiar velocity prevents us from obtaining a quantitative constraint on the inclination angle of the merger axis. The lack of pronounced substructure in the cluster gas distribution and the proximity

  1. Evidence for Quasi-Periodic X-ray Dips from an ULX: Implications for the Binary Motion and the Orbital Inclination

    NASA Technical Reports Server (NTRS)

    Pasham, Dheeraj R.; Strohmayer, Tod E.

    2012-01-01

    We report results from long-term X-ray (0.3-8.0 keY) monitoring of the ultraluminous X-ray source NGC 5408 X-1 with the Swift/X-Ray Telescope. Our primary results are: (1) the discovery of quasi-periodic dips in the X-ray intensity that recur on average every 243 days, (2) the detection of an energy-dependent (variability amplitude decreases with increasing energy), quasi-sinusoidal X-ray modulation with a period of 112.6 +/- 4 days the amplitude of which decreases during the second half of the light curve and (3) energy spectral evidence for an increase in photoelectric absorption during the last continuous segment of the data, possibly due to a change in the ionization state of the circumbinary material. We interpret the X-ray modulations in the context of binary motion in analogy to that seen in high-inclination low-mass X-ray binaries. If correct, this implies that NGC 5408 X-1 is in a binary with an orbital period of 243 +/- 23 days in contrast to the 115.5 day quasi-sinusoidal period previously reported. In addition, if the X-ray modulation is caused by vertically structured obscuring material in the accretion disk (similar to the phenomenon of dipping LMXBs), this would imply a high value for the inclination of the orbit. A comparison with estimates from accreting X-ray binaries suggests an inclination approx > 60 deg. We note that, in principle, a precessing accretion disk could also produce the observed X-ray modulations.

  2. The Behavior of Accretion Disks in Low Mass X-ray Binaries: Disk Winds and Alpha Model

    NASA Astrophysics Data System (ADS)

    Bayless, Amanda J.

    2010-01-01

    This dissertation presents research on two low mass X-ray binaries. The eclipsing low-mass X-ray binary 4U 1822-371 is the prototypical accretion disk corona (ADC) system. We have obtained new time-resolved UV spectroscopy with the ACS/SBC on the Hubble Space Telescope and new V- and J-band photometry with the 1.3-m SMARTS telescope at CTIO. We show that the accretion disk in the system has a strong wind with projected velocities up to 4000 km/s as determined from the Doppler width of the C IV emission line. The broad and shallow eclipse indicates that the disk has a vertically-extended, optically-thick component at optical wavelengths. This component extends almost to the edge of the disk and has a height equal to 50% of the disk radius. As it has a low brightness temperature, we identify it as the optically-thick base of the disk wind. V1408 Aql (=4U 1957+115) is a low mass X-ray binary which continues to be a black hole candidate. We have new photometric data of this system from the Otto Struve 2.1-m telescope's high speed CCD photometer at McDonald Observatory. The light curve is largely sinusoidal which we model with two components: a constant light source from the disk and a sinusoidal modulation at the orbital period from the irradiated face of the companion star. This is a radical re-interpretation of the orbital light curve. We do not require a large or asymmetric disk rim to account for the modulation in the light curve. Thus, the orbital inclination is unconstrained in our new model, removing the foundation for any claims of the compact object being a black hole.

  3. ASCA Observation of MS 1603.6+2600 (=UW Coronae Borealis): A Dipping Low-Mass X-ray Binary in the Outer Halo?

    NASA Technical Reports Server (NTRS)

    Mukai, Koji; Smale, Alan; Stahle, Caroline K.; Schlegel, Eric M.; Wijnands, Rudy; White, Nicholas E. (Technical Monitor)

    2001-01-01

    MS 1603.6+2600 is a high-latitude X-ray binary with a 111 min orbital period, thought to be either an unusual cataclysmic variable or an unusual low-mass X-ray binary. In an ASCA observation in 1997 August, we find a burst whose light curve suggests a Type 1 (thermonuclear flash) origin. We also find an orbital X-ray modulation in MS 1603.6+2600, which is likely to be periodic dips, presumably due to azimuthal structure in the accretion disk. Both are consistent with this system being a normal low-mass X-ray binary harboring a neutron star, but at a great distance. We tentatively suggest that MS 1603.6+2600 is located in the outer halo of the Milky Way, perhaps associated with the globular cluster Palomar 14, 11 deg away from MS 1603.6+2600 on the sky at an estimated distance of 73.8 kpc.

  4. Observation of the black hole candidate X-ray binary Swift J1357.2 0933 in quies

    NASA Astrophysics Data System (ADS)

    Armas Padilla, Montserrat

    2012-10-01

    We propose a 40 ksec XMM Newton observation of the low mass X-ray binary black hole system Swift J1357.2 0933 in the quiescent state. The low column density towards the source makes it possible to obtain its quiescent lumi- nosity down to LX ~1E30 ergs s-1. This limit, together with its short orbital period of 2.8 hours makes it possible to test the ADAF interpretation for emission in quiescent black holes systems by testing the quiescent luminosity-orbital period correlation in the unexplored regime of very short orbital periods.

  5. Long-Term X-ray and Optical Study of the Black Hole X-ray Binaries in the Elliptical Galaxies NGC 4472

    NASA Astrophysics Data System (ADS)

    Zepf, Steve; Maccarone, Tom; Steele, Matthew; Kundu, Arunav

    2014-02-01

    We have been awarded time by the Chandra TAC to observe the black hole X-ray source in the extragalactic globular cluster RZ2109 with both Chandra and GMOS once in each of the next three years. We will use these data to track the variabilty of RZ109 in both X-rays and its remarkable [OIII]5007 emission line. This will enable us to constrain the spatial scale of the [OIII] emission and the nature of this black hole source.

  6. The population of low-mass X-ray binaries ejected from black-hole retaining globular clusters

    NASA Astrophysics Data System (ADS)

    Giesler, Matthew; Clausen, Drew; Ott, Christian

    2017-01-01

    The fate of stellar-mass black holes (BHs) formed in globular clusters (GCs) is still widely uncertain; recent studies suggest that GCs may retain a substantial population of BHs, in contrast to the long held belief of a few to zero BHs. We model the population of BH low-mass X-ray binaries (BH-LMXB) ejected from GCs that are representative of Milky Way GCs with variable BH populations. We simulate the formation of BH-binaries in GCs through exchange interactions between binary and single stars in the company of tens to hundreds of BHs. We construct Monte Carlo realizations of the present day BH-LMXB population that account for both the binary evolution of the ejected systems and the dynamical evolution of these binaries in the Milky Way potential. We find that the orbital parameters of the ejected binaries are sensitive to both the GC's observable structural parameters and its unobservable BH population. Our results suggest that these dynamically formed BH-LMXBs will be easily distinguishable, by their distinctive kinematic properties and larger BH masses, from those produced in the field. Identifying this population of BH-LMXBs, an ideal observable proxy for elusive single BHs, would provide observational constraints on the GC BH retention fraction.

  7. Birth of Massive Black Hole Binaries

    SciTech Connect

    Colpi, M.; Dotti, M.; Mayer, L.; Kazantzidis, S.; /KIPAC, Menlo Park

    2007-11-19

    If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.

  8. The Causal Connection Between Disc and Power-Law Variability in Hard State Black Hole X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Uttley, P.; Wilkinson, T.; Cassatella, P.; Wilms, J.; Pottschimdt, K.; Hanke, M.; Boeck, M.

    2010-01-01

    We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. \\Ve show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.

  9. INVERSE COMPTON SCATTERING MODEL FOR X-RAY EMISSION OF THE GAMMA-RAY BINARY LS 5039

    SciTech Connect

    Yamaguchi, M. S.; Takahara, F.

    2012-12-20

    We propose a model for the gamma-ray binary LS 5039 in which the X-ray emission is due to the inverse Compton (IC) process instead of the synchrotron radiation. Although the synchrotron model has been discussed in previous studies, it requires a strong magnetic field which leads to a severe suppression of the TeV gamma-ray flux in conflict with H.E.S.S. observations. In this paper, we calculate the IC emission by low energy electrons ({gamma}{sub e} {approx}< 10{sup 3}) in the Thomson regime. We find that IC emission of the low energy electrons can explain the X-ray flux and spectrum observed with Suzaku if the minimum Lorentz factor of injected electrons {gamma}{sub min} is around 10{sup 3}. In addition, we show that the Suzaku light curve is well reproduced if {gamma}{sub min} varies in proportion to the Fermi flux when the distribution function of injected electrons at higher energies is fixed. We conclude that the emission from LS 5039 is well explained by the model with the IC emission from electrons whose injection properties are dependent on the orbital phase. Since the X-ray flux is primarily determined by the total number of cooling electrons, this conclusion is rather robust, although some mismatches between the model and observations at the GeV band remain in the present formulation.

  10. SXP 7.92: A Recently Rediscovered Be/X-ray Binary in the Small Magellanic Cloud, Viewed Edge On

    NASA Astrophysics Data System (ADS)

    Bartlett, E. S.; Coe, M. J.; Israel, G. L.; Clark, J. S.; Esposito, P.; D'Elia, V.; Udalski, A.

    2017-01-01

    We present a detailed optical and X-ray study of the 2013 outburst of the Small Magellanic Cloud Be/X-ray binary SXP 7.92, as well as an overview of the last 18 years of observations from OGLE, RXTE, Chandra and XMM-Newton. We revise the position of this source to RA(J2000)=00:57:58.4, Dec(J2000)=-72:22:29.5 with a 1σ uncertainty of 1.5″, correcting the previously reported position by Coe et al. (2009) by more than 20 arcminutes. We identify and spectrally classify the correct counterpart as a B1Ve star. The optical spectrum is distinguished by an uncharacteristically deep narrow Balmer series, with the Hα line in particular having a distinctive shell profile, i.e. a deep absorption core embedded in an emission line. We interpret this as evidence that we are viewing the system edge on and are seeing self obscuration of the circumstellar disc. We derive an optical period for the system of 40.0±0.3 days, which we interpret as the orbital period, and present several mechanisms to describe the X-ray/Optical behaviour in the recent outburst, in particular the "flares" and "dips" seen in the optical light curve, including a transient accretion disc and an elongated precessing disc.

  11. The orbital ephemeris and eclipse transitions of the low-mass X-ray binary EXO 0748 - 676

    SciTech Connect

    Parmar, A.N.; Smale, A.P.; Verbunt, F.; Corbet, R.H.D. NASA, Goddard Space Flight Center, Greenbelt, MD Utrecht Rijksuniversitet Institute of Space and Astronautical Science, Sagamihara )

    1991-01-01

    Using the eclipses as fiducial markers, an updated ephemeris for EXO 0748 - 676 is derived and evidence is found that between February 1985 and March 1989 the 3.82-h orbital period of EXO 0748 - 676 decreased with a time scale of -5 x 10 to the 6th yr. The sense of this change is the same as that predicted by simple models for the evolution of low-mass X-ray binaries containing main-sequence companions, but is a factor about 100 faster than expected. This rapid change in orbital period could result from the expansion of the companion due to the effects of X-ray heating. The eclipse transition durations are variable, with the shortest observed taking 1.5 s and the longest 40 s. This latter figure is about an order of magnitude too large to be due to absorption effects in the atmosphere of the secondary assuming a Roche geometry and likely stellar temperature. Either flaring activity or the presence of an X-ray heated evaporative wind or a corona may enhance the scale height of the companion's atmosphere producing the extended eclipse transitions. 38 refs.

  12. BROADBAND X-RAY PROPERTIES OF THE GAMMA-RAY BINARY 1FGL J1018.6–5856

    SciTech Connect

    An, Hongjun; Bhalerao, Varun; Boggs, Steven E.; Craig, William W.; Tomsick, John A.; Christensen, Finn E.; Hailey, Charles J.; Kaspi, Victoria M.; Natalucci, Lorenzo; Stern, Daniel; Zhang, William W.

    2015-06-20

    We report on NuSTAR, XMM-Newton, and Swift observations of the gamma-ray binary 1FGL J1018.6–5856. We measure the orbital period to be 16.544 ± 0.008 days using Swift data spanning 1900 days. The orbital period is different from the 2011 gamma-ray measurement which was used in the previous X-ray study of An et al. using ∼400 days of Swift data, but is consistent with a new gamma-ray solution reported in 2014. The light curve folded on the new period is qualitatively similar to that reported previously, having a spike at phase 0 and broad sinusoidal modulation. The X-ray flux enhancement at phase 0 occurs more regularly in time than was previously suggested. A spiky structure at this phase seems to be a persistent feature, although there is some variability. Furthermore, we find that the source flux clearly correlates with the spectral hardness throughout all orbital phases, and that the broadband X-ray spectra measured with NuSTAR, XMM-Newton, and Swift are well fit with an unbroken power-law model. This spectrum suggests that the system may not be accretion-powered.

  13. The Einstein objective grating spectrometer survey of galactic binary X-ray sources

    NASA Technical Reports Server (NTRS)

    Vrtilek, S. D.; Mcclintock, J. E.; Seward, F. D.; Kahn, S. M.; Wargelin, B. J.

    1991-01-01

    The results of observations of 22 bright Galactic X-ray point sources are presented, and the most reliable measurements to date of X-ray column densities to these sources are derived. The results are consistent with the idea that some of the objects have a component of column density intrinsic to the source in addition to an interstellar component. The K-edge absorption due to oxygen is clearly detected in 10 of the sources and the Fe L and Ne K edges are detected in a few. The spectra probably reflect emission originating in a collisionally excited region combined with emission from a photoionized region excited directly by the central source.

  14. IGR J06074+2205 is a Be X-ray Binary

    NASA Astrophysics Data System (ADS)

    Tomsick, J. A.; Chaty, S.; Rodriguez, J.; Walter, R.; Kaaret, P.

    2006-12-01

    The X-ray source IGR J06074+2205 was discovered using data from observations made by INTEGRAL in 2003 February. (Chenevez et al. 2004, ATEL#223). Two different sources in the 2 arcminute INTEGRAL error circle have been suggested as possible counterparts. The first is the radio source NVSS J060718 +220452 (Pooley et al. 2004, ATEL#226; Pandey et al. 2006), while the second possible counterpart is a Be star (Halpern & Tyagi 2005, ATEL#682; Masetti et al.

  15. Long-term optical observations of the Be/X-ray binary X Per

    SciTech Connect

    Li, Hui; Yan, Jingzhi; Zhou, Jianeng; Liu, Qingzhong

    2014-12-01

    We present optical spectroscopic observations of X Per from 1999 to 2013 with the 2.16 m telescope at Xinglong Station and the 2.4 m telescope at Lijiang Station, National Astronomical Observatories of China. Combining these observations with the public optical photometric data, we find certain epochs of anti-correlations between the optical brightness and the intensity of the Hα and He I 6678 lines, which may be attributed to the mass ejections from the Be star; however, alternative explanations are also possible. The variability of the Fe II 6317 line in the spectra of X Per might also be caused by the shocked waves formed after the mass ejections from the Be star. The X-ray activities of the system might also be connected with the mass ejection events from the Be star. When the ejected materials were transported from the surface of the Be star to the orbit of the neutron star, an X-ray flare could be observed in its X-ray light curves. We use the neutron star as a probe to constrain the motion of the ejected material in the circumstellar disk. With the diffusion time of the ejected material from the surface of the Be star to the orbit of neutron star, the viscosity parameter α of the circumstellar disk is estimated to be 0.39 and 0.28 for the different times, indicating that the disk around the Be star may be truncated by the neutron star at the 2:1 resonance radius and that a Type I X-ray outburst is unlikely to be observed in X Per.

  16. SWIFT J1626.6-5156 is not a high mass X-ray binary

    NASA Astrophysics Data System (ADS)

    Rea, N.; Testa, V.; Israel, G. L.; Antonelli, A.; Jonker, P.; Belloni, T.; Campana, S.; Stella, L.

    2006-01-01

    on behalf of E. Molinari, G. Chincarini, F.M. Zerbi, S. Covino, G. Tosti, P. Conconi, G. Cutispoto, L. Nicastro, E. Palazzi, F. Vitali, F. D'Alessio, E. Meurs, P. Goldoni and the REMIR/ROSS collaboration We report on infrared observations of the newly discovered transient X-ray pulsar SWIFT J1626.6-5156 (Palmer et al., ATEL #678, Markwardt & Swank, ATEL #679 and Campana et al., ATEL #688).

  17. A New Comptonization Model for Weakly Magnetized, Accreting Neutron Stars in Low-Mass X-Ray Binaries

    NASA Astrophysics Data System (ADS)

    Farinelli, Ruben; Titarchuk, Lev; Paizis, Ada; Frontera, Filippo

    2008-06-01

    We have developed a new model for the X-ray spectral fitting package XSPEC that takes into account the effects of both thermal and dynamical (i.e., bulk) Comptonization. The model consists of two components: one is the direct blackbody-like emission due to seed photons that are not subjected to effective Compton scattering, while the other is a convolution of the Green's function of the energy operator with a blackbody-like seed photon spectrum. When combined thermal and bulk effects are considered, the analytical form of the Green's function may be obtained as a solution of the diffusion equation describing Comptonization. Using data from the BeppoSAX, INTEGRAL, and RXTE satellites, we test our model on the spectra of a sample of six bright neutron star low-mass X-ray binaries with low magnetic fields, covering three different spectral states. Particular attention is given to the transient power-law-like hard X-ray (gtrsim30 keV) tails, which we interpret in the framework of the bulk motion Comptonization process. We show that the values of the best-fit δ-parameter, which represents the importance of bulk with respect to thermal Comptonization, can be physically meaningful and can at least qualitatively describe the physical conditions of the environment in the innermost part of the system. Moreover, we show that in fitting the thermal Comptonization spectra to the X-ray spectra of these systems, the best-fit parameters of our model are in excellent agreement with those from compTT, a broadly used and well-established XSPEC model.

  18. Swift reveals the eclipsing nature of the high-mass X-ray binary IGR J16195-4945

    NASA Astrophysics Data System (ADS)

    Cusumano, G.; La Parola, V.; Segreto, A.; D'Aì, A.

    2016-03-01

    IGR J16195-4945 is a hard X-ray source discovered by INTEGRAL during the Core Programme observations performed in 2003. We analysed the X-ray emission of this source exploiting the Swift-Burst Alert Telescope (BAT) survey data from 2004 December to 2015 March, and all the available Swift-X-ray Telescope (XRT)-pointed observations. The source is detected at a high significance level in the 123-month BAT survey data, with an average 15-150 keV flux of the source of ˜1.6 mCrab. The timing analysis on the BAT data reveals with a significance higher than six standard deviations the presence of a modulated signal with a period of 3.945 d, that we interpret as the orbital period of the binary system. The folded light curve shows a flat profile with a narrow full eclipse lasting ˜3.5 per cent of the orbital period. We requested phase-constrained XRT observations to obtain a more detailed characterization of the eclipse in the soft X-ray range. Adopting reasonable guess values for the mass and radius of the companion star, we derive a semimajor orbital axis of ˜ 31 R⊙, equivalent to ˜1.8 times the radius of the companion star. From these estimates and from the duration of the eclipse, we derive an orbital inclination between 55 and 60 deg. The broad-band time-averaged XRT+BAT spectrum is well modelled with a strongly absorbed flat power law, with absorbing column NH = 7 × 1022 cm-2 and photon index Γ = 0.5, modified by a high energy exponential cutoff at Ecut = 14 keV.

  19. Flows of X-ray gas reveal the disruption of a star by a massive black hole.

    PubMed

    Miller, Jon M; Kaastra, Jelle S; Miller, M Coleman; Reynolds, Mark T; Brown, Gregory; Cenko, S Bradley; Drake, Jeremy J; Gezari, Suvi; Guillochon, James; Gultekin, Kayhan; Irwin, Jimmy; Levan, Andrew; Maitra, Dipankar; Maksym, W Peter; Mushotzky, Richard; O'Brien, Paul; Paerels, Frits; de Plaa, Jelle; Ramirez-Ruiz, Enrico; Strohmayer, Tod; Tanvir, Nial

    2015-10-22

    Tidal forces close to massive black holes can violently disrupt stars that make a close approach. These extreme events are discovered via bright X-ray and optical/ultraviolet flares in galactic centres. Prior studies based on modelling decaying flux trends have been able to estimate broad properties, such as the mass accretion rate. Here we report the detection of flows of hot, ionized gas in high-resolution X-ray spectra of a nearby tidal disruption event, ASASSN-14li in the galaxy PGC 043234. Variability within the absorption-dominated spectra indicates that the gas is relatively close to the black hole. Narrow linewidths indicate that the gas does not stretch over a large range of radii, giving a low volume filling factor. Modest outflow speeds of a few hundred kilometres per second are observed; these are below the escape speed from the radius set by variability. The gas flow is consistent with a rotating wind from the inner, super-Eddington region of a nascent accretion disk, or with a filament of disrupted stellar gas near to the apocentre of an elliptical orbit. Flows of this sort are predicted by fundamental analytical theory and more recent numerical simulations.

  20. A Search for Photo-ionized Absorbers in High Mass X-ray Binaries: 4U 1907+09

    NASA Astrophysics Data System (ADS)

    Balman, Solen

    2007-10-01

    In order to further our understanding of the emitting and absorbing material in high-mass X-ray binaries (HMXB) and the accretion states of the sources,we propose a total of 30 ksec XMM-Newton observation of 4U 1907+09 to be conducted as two 15 ksec observations at different binary phases.In two archival ASCA SIS spectra of 4U 1907+09,we found evidence for the presence of 6.9 keV Fe XXVI absorption features at around 2sigma confidence which will yield 5sigma detection with EPIC pn CCDs and the modelling will allow the properties of a photo-ionized absorber to be determined for the first time in a HMXB. Our proposed observation at the chosen phases will for the first time determine spectra at low count rate levels over a factor of 100 difference from the source.

  1. X-ray observations of XSS J12270-4859 in a new low state: A transformation to a disk-free rotation-powered pulsar binary

    SciTech Connect

    Bogdanov, Slavko; Patruno, Alessandro; Archibald, Anne M.; Bassa, Cees; Hessels, Jason W. T.; Janssen, Gemma H.; Stappers, Ben W.

    2014-07-01

    We present XMM-Newton and Chandra observations of the low-mass X-ray binary XSS J12270-4859, which experienced a dramatic decline in optical/X-ray brightness at the end of 2012, indicative of the disappearance of its accretion disk. In this new state, the system exhibits previously absent orbital-phase-dependent, large-amplitude X-ray modulations with a decline in flux at superior conjunction. The X-ray emission remains predominantly non-thermal but with an order of magnitude lower mean luminosity and significantly harder spectrum relative to the previous high flux state. This phenomenology is identical to the behavior of the radio millisecond pulsar (MSP) binary PSR J1023+0038 in the absence of an accretion disk, where the X-ray emission is produced in an intra-binary shock driven by the pulsar wind. This further demonstrates that XSS J12270-4859 no longer has an accretion disk and has transformed to a full-fledged eclipsing 'redback' system that hosts an active rotation-powered MSP. There is no evidence for diffuse X-ray emission associated with the binary that may arise due to outflows or a wind nebula. An extended source situated 1.'5 from XSS J12270-4859 is unlikely to be associated, and is probably a previously uncataloged galaxy cluster.

  2. Implementation of the frequency-modulated sideband search method for gravitational waves from low mass x-ray binaries

    NASA Astrophysics Data System (ADS)

    Sammut, L.; Messenger, C.; Melatos, A.; Owen, B. J.

    2014-02-01

    We describe the practical implementation of the sideband search, a search for periodic gravitational waves from neutron stars in binary systems. The orbital motion of the source in its binary system causes frequency modulation in the combination of matched filters known as the F-statistic. The sideband search is based on the incoherent summation of these frequency-modulated F-statistic sidebands. It provides a new detection statistic for sources in binary systems, called the C-statistic. The search is well suited to low-mass x-ray binaries, the brightest of which, called Sco X-1, is an ideal target candidate. For sources like Sco X-1, with well-constrained orbital parameters, a slight variation on the search is possible. The extra orbital information can be used to approximately demodulate the data from the binary orbital motion in the coherent stage, before incoherently summing the now reduced number of sidebands. We investigate this approach and show that it improves the sensitivity of the standard Sco X-1 directed sideband search. Prior information on the neutron star inclination and gravitational wave polarization can also be used to improve upper limit sensitivity. We estimate the sensitivity of a Sco X-1 directed sideband search on ten days of LIGO data and show that it can beat previous upper limits in current LIGO data, with a possibility of constraining theoretical upper limits using future advanced instruments.

  3. The MASSIVE Survey. IV. The X-ray Halos of the Most Massive Early-type Galaxies in the Nearby Universe

    NASA Astrophysics Data System (ADS)

    Goulding, Andy D.; Greene, Jenny E.; Ma, Chung-Pei; Veale, Melanie; Bogdan, Akos; Nyland, Kristina; Blakeslee, John P.; McConnell, Nicholas J.; Thomas, Jens

    2016-08-01

    Studies of the physical properties of local elliptical galaxies are shedding new light on galaxy formation. Here we present the hot-gas properties of 33 early-type systems within the MASSIVE galaxy survey that have archival Chandra X-ray observations, and we use these data to derive X-ray luminosities ({L}{{X,gas}}) and plasma temperatures ({T}{{gas}}) for the diffuse gas components. We combine this with the {{ATLAS}}{{3D}} survey to investigate the X-ray-optical properties of a statistically significant sample of early-type galaxies across a wide range of environments. When X-ray measurements are performed consistently in apertures set by the galaxy stellar content, we deduce that all early types (independent of galaxy mass, environment, and rotational support) follow a universal scaling law such that {L}{{X,gas}}\\propto {T}{{gas}}˜ 4.5. We further demonstrate that the scatter in {L}{{X,gas}} around both K-band luminosity (L K ) and the galaxy stellar velocity dispersion ({σ }e) is primarily driven by {T}{{gas}}, with no clear trends with halo mass, radio power, or angular momentum of the stars. It is not trivial to tie the gas origin directly to either stellar mass or galaxy potential. Indeed, our data require a steeper relation between {L}{{X,gas}},{L}K, and {σ }e than predicted by standard mass-loss models. Finally, we find that {T}{{gas}} is set by the galaxy potential inside the optical effective radius. We conclude that within the innermost 10-30 kpc region, early types maintain pressure-supported hot gas, with a minimum {T}{{gas}} set by the virial temperature, but the majority show evidence for additional heating.

  4. Chemical abundances of the secondary star in the neutron star X-ray binary Cygnus X-2

    NASA Astrophysics Data System (ADS)

    Suárez-Andrés, L.; González Hernández, J. I.; Israelian, G.; Casares, J.; Rebolo, R.

    2015-03-01

    We present Utrecht Echelle Spectrograph@William Herschel Telescope high-resolution spectra of the low-mass X-ray binary (LMXB) Cygnus X-2. We have derived the stellar parameters of the secondary star using χ2 minimization procedure, and taking into account any possible veiling from the accretion disc. We determine a metallicity higher than solar ([Fe/H] = 0.27 ± 0.19), as seen also in the neutron star X-ray binary Centaurus X-4. The high quality of the secondary's spectrum allow us to determine the chemical abundances of O, Mg, Si, Ca, S, Ti, Fe, and Ni. We found that some α-elements (Mg, Si, S, Ti) are enhanced, consistent with a scenario of contamination of the secondary star during the supernova event. Surprisingly oxygen appears to be underabundant, whereas enhanced abundances of Fe and Ni are measured. Assuming that these abundances come from matter that has been processed in the SN and then captured by the secondary star, we explore different SN explosion scenarios with diverse geometries. A non-spherically symmetric SN explosion, with a low mass cut, seems to reproduce better the observed abundance pattern of the secondary star compared to the spherical case.

  5. A Broad-band Spectral and Timing Study of the X-Ray Binary System Centaurus X-3

    NASA Technical Reports Server (NTRS)

    Audley, Michael Damian

    1998-01-01

    This dissertation describes a multi-mission investigation of the high mass X-ray binary pulsar Centaurus X-3. Cen X-3 was observed with the Broad Band X-Ray Telescope (BBXRT) in December 1990. This was the first high-resolution solid state X-ray spectrometer to cover the iron K fluorescence region. The Fe K emission feature was resolved into two components for the first time. A broad 6.7 keV feature was found to be a blend of lines from Fe XXI-Fe XXVI with energies ranging from 6.6 to 6.9 keV due to photoionization of the companion's stellar wind. A narrow line at 6.4 keV due to fluorescence of iron in relatively low ionization states was also found. The quasi-periodic oscillations (QPO) at about 40 mHz were used to estimate the surface magnetic field of Cen X-3 as approx. 2.6 x 10(exp 12) G and to predict that there should be a cyclotron scattering resonance absorption feature (CSRF) near 30 keV. In order to further resolve the iron line complex and to investigate the pulse-phase dependence of the iron line intensities, Cen X-3 was observed with the Advanced Satellite for Cosmology and Astrophysics (ASCA). Using ASCA's state-of-the-art non-dispersive X-ray spectrometers the 6.4 keV fluorescent iron line was found to be pulsing while the intensities of the 6.7 and 6.9 keV recombination lines do not vary with pulse phase. This confirms that the 6.4 keV line is due to reflection by relatively neutral matter close to the neutron star while the recombination lines originate in the extended stellar wind. The continuum spectrum was found to be modified by reflection from matter close to the neutron star. Observations with the EXOSAT GSPC were used to search for a CSRF. The EXOSAT spectra were consistent with the presence of a CSRF but an unambiguous detection was not possible because of a lack of sensitivity at energies higher than the cyclotron energy. Cen X-3 was then observed with the Rossi X-Ray Timing Explorer (RXTE) and evidence for a CSRF at 25.1 +/- 0.3 keV was

  6. 1RXS J180408.9-342058: An ultra compact X-ray binary candidate with a transient jet

    NASA Astrophysics Data System (ADS)

    Baglio, M. C.; D'Avanzo, P.; Campana, S.; Goldoni, P.; Masetti, N.; Muñoz-Darias, T.; Patiño-Álvarez, V.; Chavushyan, V.

    2016-03-01

    Aims: We present a detailed near-infrared/optical/UV study of the transient low-mass X-ray binary 1RXS J180408.9-342058 performed during its 2015 outburst, which is aimed at determining the nature of its companion star. Methods: We obtained three optical spectra (R ~ 1000) at the 2.1 m San Pedro Mártir Observatory telescope (México). We performed optical and NIR photometric observations with both the REM telescope and the New Technology Telescope (NTT) in La Silla. We obtained optical and UV observations from the Swift archive. Finally, we performed optical polarimetry of the source using the EFOSC2 instrument mounted on the NTT. Results: The optical spectrum of the source is almost featureless since the hydrogen and He I emissions lines, typically observed in LMXBs, are not detected. Similarly, carbon and oxygen lines are not observed either. We marginally detect the He II 4686 Å emission line, suggesting the presence of helium in the accretion disc. No significant optical polarisation level was observed. Conclusions: The lack of hydrogen and He I emission lines in the spectrum implies that the companion is likely not a main-sequence star. Driven by the tentative detection of the He II 4686 Å emission line, we suggest that the system could harbour a helium white dwarf. If this is the case, 1RXS J180408.9-342058 would be an ultra-compact X-ray binary. By combining an estimate of the mass accretion rate together with evolutionary tracks for a He white dwarf, we obtain a tentative orbital period of ~40 min. We also built the NIR-optical-UV spectral energy distribution (SED) of the source at two different epochs. One SED was gathered when the source was in the soft X-ray state and this SED is consistent with the presence of a single thermal component. The second SED, obtained when the source was in the hard X-ray state, shows a thermal component along with a tail in the NIR, which likely indicates the presence of a (transient) jet. Based on observations made with

  7. Interactions in Massive Colliding Wind Binaries

    NASA Technical Reports Server (NTRS)

    Corcoran, M.

    2012-01-01

    The most massive stars (M> 60 Solar Mass) play crucial roles in altering the chemical and thermodynamic properties of their host galaxies. Stellar mass is the fundamental stellar parameter that determines their ancillary properties and which ultimately determines the fate of these stars and their influence on their galactic environs. Unfortunately, stellar mass becomes observationally and theoretically less well constrained as it increases. Theory becomes uncertain mostly because very massive stars are prone to strong, variable mass loss which is difficult to model. Observational constraints are uncertain too. Massive stars are rare, and massive binary stars (needed for dynamical determination of mass) are rarer still: and of these systems only a fraction have suitably high orbital inclinations for direct photometric and spectroscopic radial-velocity analysis. Even in the small number of cases in which a high-inclination binary near the upper mass limit can be identified, rotational broadening and contamination of spectral line features from thick circumstellar material (either natal clouds or produced by strong stellar wind driven mass loss from one or both of he stellar components) biases the analysis. In the wilds of the upper HR diagram, we're often left with indirect and circumstantial means of determining mass, a rather unsatisfactory state of affairs.

  8. X-ray jet emission from the black hole X-ray binary XTE J1550-564 with CHANDRA in 2000

    NASA Astrophysics Data System (ADS)

    Tomsick, J. A.; Corbel, S.; Fender, R. P.; Miller, J. M.; Orosz, J. A.; Tzioumis, T.; Wijnands, R.; Kaaret, P.

    We have discovered an X-ray jet due to material ejected from the black hole X-ray transient XTE J1550-564 (see also the Corbel et al. contribution to these proceedings). We present results from three Chandra observations made between 2000 June and 2000 September. For these observations, a source is present that moves in an eastward direction away from the point source associated with the compact object. The separation between the new source and the compact object changes from 21''.3 in June to 23''.4 in September, implying a proper motion of 21.2 ± 7.2 mas day-1, a projected separation of 0.31-0.85 pc and a jet velocity >0.22c for a source distance range of d = 2.8-7.6 kpc. These observations represent the first time that an X-ray jet proper motion measurement has been obtained for any accretion powered Galactic or extra-galactic source. Along with a 1998 VLBI proper motion measurement, the Chandra proper motion indicates that the jet decelerated between 1998 and 2000. Although we cannot definitively determine the X-ray emission mechanism, a synchrotron origin is viable and may provide the simplest explanation for the observations.

  9. GAMMA-RAY OBSERVATIONS OF THE Be/PULSAR BINARY 1A 0535+262 DURING A GIANT X-RAY OUTBURST

    SciTech Connect

    Acciari, V. A.; Benbow, W.; Aliu, E.; Araya, M.; Cui, W.; Finley, J. P.; Arlen, T.; Aune, T.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R.; Bradbury, S. M.; Byrum, K.; Cannon, A.; Collins-Hughes, E.; Cesarini, A.; Ciupik, L.; Duke, C.; Falcone, A. E-mail: cui@purdue.edu

    2011-06-01

    Giant X-ray outbursts, with luminosities of about 10{sup 37} erg s{sup -1}, are observed roughly every five years from the nearby Be/pulsar binary 1A 0535+262. In this article, we present observations of the source with VERITAS at very high energies (VHEs; E >100 GeV) triggered by the X-ray outburst in 2009 December. The observations started shortly after the onset of the outburst and provided comprehensive coverage of the episode, as well as the 111 day binary orbit. No VHE emission is evident at any time. We also examined data from the contemporaneous observations of 1A 0535+262 with the Fermi/Large Area Telescope at high-energy photons (E > 0.1 GeV) and failed to detect the source at GeV energies. The X-ray continua measured with the Swift/X-Ray Telescope and the RXTE/PCA can be well described by the combination of blackbody and Comptonized emission from thermal electrons. Therefore, the gamma-ray and X-ray observations suggest the absence of a significant population of non-thermal particles in the system. This distinguishes 1A 0535+262 from those Be X-ray binaries (such as PSR B1259-63 and LS I +61{sup 0}303) that have been detected at GeV-TeV energies. We discuss the implications of the results on theoretical models.

  10. An `analytic dynamical magnetosphere' formalism for X-ray and optical emission from slowly rotating magnetic massive stars

    NASA Astrophysics Data System (ADS)

    Owocki, Stanley P.; ud-Doula, Asif; Sundqvist, Jon O.; Petit, Veronique; Cohen, David H.; Townsend, Richard H. D.

    2016-11-01

    Slowly rotating magnetic massive stars develop `dynamical magnetospheres' (DMs), characterized by trapping of stellar wind outflow in closed magnetic loops, shock heating from collision of the upflow from opposite loop footpoints, and subsequent gravitational infall of radiatively cooled material. In 2D and 3D magnetohydrodynamic (MHD) simulations, the interplay among these three components is spatially complex and temporally variable, making it difficult to derive observational signatures and discern their overall scaling trends. Within a simplified, steady-state analysis based on overall conservation principles, we present here an `analytic dynamical magnetosphere' (ADM) model that provides explicit formulae for density, temperature, and flow speed in each of these three components - wind outflow, hot post-shock gas, and cooled inflow - as a function of colatitude and radius within the closed (presumed dipole) field lines of the magnetosphere. We compare these scalings with time-averaged results from MHD simulations, and provide initial examples of application of this ADM model for deriving two key observational diagnostics, namely hydrogen H α emission line profiles from the cooled infall, and X-ray emission from the hot post-shock gas. We conclude with a discussion of key issues and advantages in applying this ADM formalism towards derivation of a broader set of observational diagnostics and scaling trends for massive stars with such dynamical magnetospheres.

  11. Theory and Observations of Non-Thermal Phenomena in Hot Massive Binaries

    NASA Technical Reports Server (NTRS)

    White, Richard L.; Chen, Wan

    1995-01-01

    The shock between the colliding winds in binary systems containing two massive stars accelerates particles to relativistic energies. These energetic particles can produce observable non-thermal radiation from the radio to gamma-rays. The important physical processes in such systems are very similar to those we have proposed for non-thermal emissions from single hot stars, which have shocks generated by instabilities in the radiatively driven stellar winds. This paper discusses the theory and observations of non-thermal radiation in the radio, X-ray, and gamma-ray regions from both single stars and massive binaries. Similarities and differences between the two types of systems are outlined. We discuss two important physical effects that apparently have been neglected in previous theoretical work on colliding wind binaries.

  12. The Nature of the X-Ray Binary IGR J19294+1816 from INTEGRAL, RXTE, and Swift Observations

    NASA Technical Reports Server (NTRS)

    Rodriquez, J.; Tomsick, J. A.; Bodaghee, A.; ZuritaHeras, J.-A.; Chaty, S.; Paizis, A.; Corbel, S.

    2009-01-01

    We report the results of a high-energy multi-instrumental campaign with INTEGRAL, RXTE, and Swift of the recently discovered INTEGRAL source IGR J19294+ 1816. The Swift/XRT data allow us to refine the position of the source to R.A. (J2000) = 19h 29m 55.9s, Decl. (J2000) = +18 deg 18 feet 38 inches . 4 (+/- 3 inches .5), which in turn permits us to identify a candidate infrared counterpart. The Swift and RXTE spectra are well fitted with absorbed power laws with hard (Gamma approx 1) photon indices. During the longest Swift observation, we obtained evidence of absorption in true excess to the Galactic value, which may indicate some intrinsic absorption in this source. We detected a strong (P = 40%) pulsations at 12.43781 (+/- 0.00003) s that we interpret as the spin period of a pulsar. All these results, coupled with the possible 117 day orbital period, point to IGR J19294+ 1816 being an high-mass X-ray binary (HMXB) with a Be companion star. However, while the long-term INTEGRAL/IBIS/ISGRI 18-40 keV light curve shows that the source spends most of its time in an undetectable state, we detect occurrences of short (2000-3000 s) and intense flares that are more typical of supergiant fast X-ray transients. We therefore cannot make firm conclusions on the type of system, and we discuss the possible implication of IGR J19294+1816 being an Supergiant Fast X-ray Transient (SFXT).

  13. Timing Observations of PSR J1023+0038 During a Low-mass X-Ray Binary State

    NASA Astrophysics Data System (ADS)

    Jaodand, Amruta; Archibald, Anne M.; Hessels, Jason W. T.; Bogdanov, Slavko; D'Angelo, Caroline R.; Patruno, Alessandro; Bassa, Cees; Deller, Adam T.

    2016-10-01

    Transitional millisecond pulsars (tMSPs) switch, on roughly multi-year timescales, between rotation-powered radio millisecond pulsar (RMSP) and accretion-powered low-mass X-ray binary (LMXB) states. The tMSPs have raised several questions related to the nature of accretion flow in their LMXB state and the mechanism that causes the state switch. The discovery of coherent X-ray pulsations from PSR J1023+0038 (while in the LMXB state) provides us with the first opportunity to perform timing observations and to compare the neutron star’s spin variation during this state to the measured spin-down in the RMSP state. Whereas the X-ray pulsations in the LMXB state likely indicate that some material is accreting onto the neutron star’s magnetic polar caps, radio continuum observations indicate the presence of an outflow. The fraction of the inflowing material being ejected is not clear, but it may be much larger than that reaching the neutron star’s surface. Timing observations can measure the total torque on the neutron star. We have phase-connected nine XMM-Newton observations of PSR J1023+0038 over the last 2.5 years of the LMXB state to establish a precise measurement of spin evolution. We find that the average spin-down rate as an LMXB is 26.8 ± 0.4% faster than the rate (-2.39 × 10-15 Hz s-1) determined during the RMSP state. This shows that negative angular momentum contributions (dipolar magnetic braking, and outflow) exceed positive ones (accreted material), and suggests that the pulsar wind continues to operate at a largely unmodified level. We discuss implications of this tight observational constraint in the context of possible accretion models.

  14. THE Be/X-RAY BINARY SWIFT J1626.6-5156 AS A VARIABLE CYCLOTRON LINE SOURCE

    SciTech Connect

    DeCesar, Megan E.; Miller, M. Coleman; Boyd, Patricia T.; Pottschmidt, Katja; Wilms, Joern; Suchy, Slawomir

    2013-01-01

    Swift J1626.6-5156 is a Be/X-ray binary that was in outburst from 2005 December until 2008 November. We have examined Rossi X-ray Timing Explorer/Proportional Counter Array (PCA) and High Energy X-ray Timing Explorer spectra of three long observations of this source taken early in its outburst, when the PCA 2-20 keV count rate was >70 counts s{sup -1} PCU{sup -1}, as well as several combined observations from different stages of the outburst. The spectra are best fit with an absorbed cutoff power law with a {approx}6.4 keV iron emission line and a Gaussian optical depth absorption line at {approx}10 keV. We present strong evidence that this absorption-like feature is a cyclotron resonance scattering feature, making Swift J1626.6-5156 a new candidate cyclotron line source. The redshifted energy of {approx}10 keV implies a magnetic field strength of {approx}8.6(1 + z) Multiplication-Sign 10{sup 11} G in the region of the accretion column close to the magnetic poles where the cyclotron line is produced. Analysis of phase-averaged spectra spanning the duration of the outburst suggests a possible positive correlation between the fundamental cyclotron energy and source luminosity. Phase-resolved spectroscopy from a long observation reveals a variable cyclotron line energy, with phase dependence similar to a variety of other pulsars, as well as the first harmonic of the fundamental cyclotron line.

  15. CHANDRA OBSERVATIONS OF GALAXY ZOO MERGERS: FREQUENCY OF BINARY ACTIVE NUCLEI IN MASSIVE MERGERS

    SciTech Connect

    Teng, Stacy H.; Darg, Dan W.; Kaviraj, Sugata; Lintott, Chris J.; Oh, Kyuseok; Cardamone, Carolin N.; Keel, William C.; Simmons, Brooke D.; Treister, Ezequiel

    2012-07-10

    We present the results from a Chandra pilot study of 12 massive galaxy mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 10{sup 11} M{sub Sun} that already have optical active galactic nucleus (AGN) signatures in at least one of the progenitors. We find that the coincidences of optically selected active nuclei with mildly obscured (N{sub H} {approx}< 1.1 Multiplication-Sign 10{sup 22} cm{sup -2}) X-ray nuclei are relatively common (8/12), but the detections are too faint (<40 counts per nucleus; f{sub 2-10keV} {approx}< 1.2 Multiplication-Sign 10{sup -13} erg s{sup -1} cm{sup -2}) to reliably separate starburst and nuclear activity as the origin of the X-ray emission. Only one merger is found to have confirmed binary X-ray nuclei, though the X-ray emission from its southern nucleus could be due solely to star formation. Thus, the occurrences of binary AGNs in these mergers are rare (0%-8%), unless most merger-induced active nuclei are very heavily obscured or Compton thick.

  16. Chandra Observations of Galaxy Zoo Mergers: Frequency of Binary Active Nuclei in Massive Mergers

    NASA Technical Reports Server (NTRS)

    Teng, Stacy H.; Schawinski, Kevin; Urry, C. Megan; Darg, Dan W.; Kaviraj, Sugata; Oh, Kyuseok; Bonning, Erin W.; Cardamone, Carolin N.; Keel, William C.; Lintott, Chris J.; Simmons, Brooke D.; Treister, Ezequiel

    2012-01-01

    We present the results from a Chandra pilot study of 12 massive galaxy mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 1011 M that already have optical AGN signatures in at least one of the progenitors. We find that the coincidences of optically selected active nuclei with mildly obscured (N(sub H) approx < 1.1 10(exp 22)/sq cm) X-ray nuclei are relatively common (8/12), but the detections are too faint (< 40 counts per nucleus; (sub -10) keV approx < 1.2 10(exp -13) erg/s/sq cm) to reliably separate starburst and nuclear activity as the origin of the X-ray emission. Only one merger is found to have confirmed binary X-ray nuclei, though the X-ray emission from its southern nucleus could be due solely to star formation. Thus, the occurrences of binary AGN in these mergers are rare (0-8%), unless most merger-induced active nuclei are very heavily obscured or Compton thick.

  17. Chandra Observations of Galaxy Zoo Mergers: Frequency of Binary Active Nuclei in Massive Mergers

    NASA Technical Reports Server (NTRS)

    Teng, Stacy H.; Schwainski, Kevin; Urry, C. Megan; Darg, Dan W.; Kaviraj, Sugata; Oh, Kyuseok; Bonning, Erin W.; Cardamone, Carolin N.; Keel, William C.; Lintott, Chris J.; Simmons, Brooke D.; Treister, Ezequiel

    2012-01-01

    We present the results from a Chandra pilot study of 12 massive mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 10(sup 11) solar mass that already have optical AGN signatures in at least one of the progenitors. We find that the coincidences of optically selected active nuclei with mildly obscured (N(sub H) less than or approximately 1.1 x 10(exp 22) per square centimeter) X-ray nuclei are relatively common (8/12), but the detections are too faint (less than 40 counts per nucleus; f(sub 2-10 keV) less than or approximately 1.2 x 10(exp -13) ergs per second per square centimeter) to separate starburst and nuclear activity as the origin of the X-ray emission. Only one merger is found to have confirmed binary X-ray nuclei, though the X-ray emission from its southern nucleus could be due solely to star formation. Thus, the occurrences of binary AGN in these mergers are rare (0-8%), unless most merger-induced active nuclei are very heavily obscured or Compton thick.

  18. STUDY OF THE SPECTRAL AND TEMPORAL CHARACTERISTICS OF X-RAY EMISSION OF THE GAMMA-RAY BINARY LS 5039 WITH SUZAKU

    SciTech Connect

    Takahashi, Tadayuki; Kishishita, Tetsuichi; Khangulyan, Dmitry; Aharonian, Felix A.; Bosch-Ramon, Valenti; Hinton, Jim A.

    2009-05-20

    We report on the results from Suzaku broadband X-ray observations of the galactic binary source LS 5039. The Suzaku data, which have continuous coverage of more than one orbital period, show strong modulation of the X-ray emission at the orbital period of this TeV gamma-ray emitting system. The X-ray emission shows a minimum at orbital phase {approx}0.1, close to the so-called superior conjunction of the compact object, and a maximum at phase {approx}0.7, very close to the inferior conjunction of the compact object. The X-ray spectral data up to 70 keV are described by a hard power law with a phase-dependent photon index which varies within {gamma} {approx_equal} 1.45- 1.61. The amplitude of the flux variation is a factor of 2.5, but is significantly less than that of the factor {approx}8 variation in the TeV flux. Otherwise the two light curves are similar, but not identical. Although periodic X-ray emission has been found from many galactic binary systems, the Suzaku result implies a phenomenon different from the 'standard' origin of X-rays related to the emission of the hot accretion plasma formed around the compact companion object. The X-ray radiation of LS 5039 is likely to be linked to very high energy electrons which are also responsible for the TeV gamma-ray emission. While the gamma rays are the result of inverse Compton (IC) scattering by electrons on optical stellar photons, X-rays are produced via synchrotron radiation. Yet, while the modulation of the TeV gamma-ray signal can be naturally explained by the photon-photon pair production and anisotropic IC scattering, the observed modulation of synchrotron X-rays requires an additional process, the most natural one being adiabatic expansion in the radiation production region.

  19. THE 5 hr PULSE PERIOD AND BROADBAND SPECTRUM OF THE SYMBIOTIC X-RAY BINARY 3A 1954+319

    SciTech Connect

    Marcu, Diana M.; Pottschmidt, Katja; Fuerst, Felix; Grinberg, Victoria; Mueller, Sebastian; Wilms, Joern; Postnov, Konstantin A.; Corbet, Robin H. D.; Markwardt, Craig B.; Cadolle Bel, Marion

    2011-11-20

    We present an analysis of the highly variable accreting X-ray pulsar 3A 1954+319 using 2005-2009 monitoring data obtained with INTEGRAL and Swift. This considerably extends the pulse period history and covers flaring episodes in 2005 and 2008. In 2006 the source was identified as one of only a few known symbiotic X-ray binaries (SyXBs), i.e., systems composed of a neutron star accreting from the inhomogeneous medium around an M-giant star. The extremely long pulse period of {approx}5.3 hr is directly visible in the 2008 INTEGRAL-ISGRI outburst light curve. The pulse profile is double peaked and generally not significantly energy dependent although there is an indication of possible softening during the main pulse. During the outburst a strong spin-up of -1.8 Multiplication-Sign 10{sup -4} hr hr{sup -1} occurred. Between 2005 and 2008 a long-term spin-down trend of 2.1 Multiplication-Sign 10{sup -5} hr hr{sup -1} was observed for the first time for this source. The 3-80 keV pulse peak spectrum of 3A 1954+319 during the 2008 flare could be well described by a thermal Comptonization model. We interpret the results within the framework of a recently developed quasi-spherical accretion model for SyXBs.

  20. Spinning-Up: the Case of the Symbiotic X-Ray Binary 3A 1954+319

    NASA Technical Reports Server (NTRS)

    Fuerst, F.; Marcu, D. M.; Pottschmidt, K.; Grinberg, V.; Wilms, J.; CadolleBel, M.

    2011-01-01

    We present a timing and spectral analysis of the variable X-ray source 3A 1954+319. Our analysis is mainly based on an outburst serendipitously observed during INTEGRAL Key Program observations of the Cygnus region in 2008 fall and on the Swift/BAT longterm light curve. Previous observations, though sparse, have identified the source to be one of only nine known symbiotic X-ray binaries, i.e., systems composed of an accreting neutron star orbiting in a highly inhomogeneous medium around an M-giant companion. The spectrum of3A 1954+319 above > 20 keV can be best described by a broken power law model. The extremely long pulse period of approx.5.3 hours is clearly visible in the INTEGRAL/ISGRI light curve and confirmed through an epoch folding period search. Furthermore, the light curve allows us to determine a very strong spin up of -2 x 10(exp -4) h/h during the outburst. This spin up is confirmed by the pulse period evolution calculated from Swift/BAT data. The Swift/BAT data also show a long spin-down trend prior to the 2008 outburst, which is confirmed in archival INTEGRAL/ISGRI data. We discuss possible accretion models and geometries allowing for the transfer of such large amounts of angular momentum and investigate the harder spectrum of this outburst compared to previously published results.

  1. Dust Scattering Halo from an Eclipsing X-ray Binary at 1.5 arcmin from Sgr A*

    NASA Astrophysics Data System (ADS)

    Jin, Chichuan; Haberl, Frank; Ponti, Gabriele

    2016-07-01

    AX J1745.6-2901 is an eclipsing neutron star low mass X-ray binary. This source is bright in X-rays and it has a high column density of absorbing gas along the line of sight, showcasing a strong dust scattering halo. Moreover, the dust scattering halo shows time evolution during the eclipsing phase. The combination of these phenomena can provide important information about the location of the neutron star and the dust properties along the line of sight. In this talk, I will show that based on a large set of XMM-Newton and Chandra data, we can conduct, for the first time, a powerful combined analysis of the radial profile of the dust scattering halo and the time evolution of the halo during the eclipsing phase. Our study can put constraints on the location of the source, the distribution and composition of the dust, and the metal abundance towards the source. Due to the proximity of the source to Sgr A* (only 1.5 arcmin), these properties are highly relevant to the dust in the Galactic centre, and are likely to be similar as the dust properties on the line of sight towards Sgr A*.

  2. ARE SPECTRAL AND TIMING CORRELATIONS SIMILAR IN DIFFERENT SPECTRAL STATES IN BLACK HOLE X-RAY BINARIES?

    SciTech Connect

    Kalamkar, M.; Klis, M. van der; Reynolds, M. T.; Miller, J. M.; Altamirano, D.

    2015-03-20

    We study the outbursts of the black hole X-ray binaries MAXI J1659-152, SWIFT J1753.5-0127, and GX 339-4 with the Swift X-ray Telescope (XRT). The bandpass of the XRT has access to emission from both components of the accretion flow: the accretion disk and the corona/hot flow. This allows a correlated spectral and variability study, with variability from both components of the accretion flow. We present for the first time a combined study of the evolution of spectral parameters (disk temperature and radius) and timing parameters (frequency and strength) of all power spectral components in different spectral states. Comparison of the correlations in different spectral states shows that the frequency and strength of the power spectral components exhibit dependencies on the disk temperature that are different in the (low-)hard and the hard-intermediate states (HIMSs); most of these correlations that are clearly observed in the HIMS (in MAXI J1659-152 and GX 339-4) are not seen in the (low-)hard state (in GX 339-4 and SWIFT J1753.5-0127). Also, the responses of the individual frequency components to changes in the disk temperature are markedly different from one component to the next. Hence, the spectral-timing evolution cannot be explained by a single correlation that spans both these spectral states. We discuss our findings in the context of the existing models proposed to explain the origin of variability.

  3. The Be/X-Ray Binary A0535+26 During Its Recent 2009/2010 Outbursts

    NASA Technical Reports Server (NTRS)

    Caballero, I.; Pottschmidt, K.; Santangelo, A.; Barragan, L.; Klochkov, D.; Ferrigno, C.; Rodriguez, J.; Kretschmar, P.; Suchy, S.; Marcu, D. M.; Mueller, D.; Wilms, J.; Kreykenbohm, I.; Rothschild, R. E.; Staubert, R.; Finger, M. H.; Camero-Arranz, A.; Makishima, K.; Mihara, T.; Nakajima, M.; Enoto, T.; Iwakiri, W.; Terada, Y.

    2011-01-01

    The Be/X-ray binary A0535+26 showed a giant outburst in December 2009 that reached approximately 5.14 Crab in thc 15-50 keV range. Unfortunately, due to Sun constraints it could not be observed by most X-ray satellites. The outburst was preceded by four weaker outbursts associated with the periastron passage of the neutron star. The fourth of them, in August 2009, presented a peculiar double-peaked light curve, with a first peak lasting about 9 days that reached a (15- 50 keV) flux of 440 mCrab. The tl ux then decreased to less than 220 mCrab, and increased again reaching 440 mCrab around the periastron. The outburst was monitored with INTEGRAL, RXTE, and Suzaku TOO observations. One orbital period (approximately 111 days) after the 2009 giant outburst, a new and unexpectedly bright outburst took place (approximately 1.4Crab in the 15-50 keV range). It was monitored with TOO observations with INTEGRAL, RXTE, Suzaku, and Swift. First results of the spectral and timing analysis of these observations are presented. with a specific focus on the cyclotron lines present in thc system and its variation with the mass accretion rate.

  4. A COMPARISON OF BROAD IRON EMISSION LINES IN ARCHIVAL DATA OF NEUTRON STAR LOW-MASS X-RAY BINARIES

    SciTech Connect

    Cackett, Edward M.; Miller, Jon M.; Reis, Rubens C.; Fabian, Andrew C.; Barret, Didier

    2012-08-10

    Relativistic X-ray disklines have been found in multiple neutron star low-mass X-ray binaries, in close analogy with black holes across the mass scale. These lines have tremendous diagnostic power and have been used to constrain stellar radii and magnetic fields, often finding values that are consistent with independent timing techniques. Here, we compare CCD-based data from Suzaku with Fe K line profiles from archival data taken with gas-based spectrometers. In general, we find good consistency between the gas-based line profiles from EXOSAT, BeppoSAX, and RXTE and the CCD data from Suzaku, demonstrating that the broad profiles seen are intrinsic to the line and not broad due to instrumental issues. However, we do find that when fitting with a Gaussian line profile, the width of the Gaussian can depend on the continuum model in instruments with low spectral resolution, though when the different models fit equally well the line widths generally agree. We also demonstrate that three BeppoSAX observations show evidence for asymmetric lines, with a relativistic diskline model providing a significantly better fit than a Gaussian. We test this by using the posterior predictive p-value method, and bootstrapping of the spectra to show that such deviations from a Gaussian are unlikely to be observed by chance.

  5. Spinning-Up: The Case of the Symbiotic X-Ray Binary 3A 1954+319

    NASA Technical Reports Server (NTRS)

    Fuerst, F.; Marcu, D. M.; Pottschmidt, K.; Grinberg, V.; Wilms, J.; Bel, M. Cadolle

    2010-01-01

    We present a timing and spectral analysis of the variable X-ray source 3A 1954+319, Our analysis is mainly based on an outburst serendipitously observed during INTEGRAL Key Program observations of the Cygnus region in 2008 fall and on the Swift/BAT longterm light curve, Previous observations, though sparse, have identified the source to be one of only nine known symbiotic X-ray binaries, i.e., systems composed of an accreting neutron star orbiting in a highly inhomogeneous medium around an M-giant companion. The spectrum of 3A 1954+319 above 20 keY can be best described by a broken power law model. The extremely long pulse period of approx.5.3 hours is clearly visible in the INTEGRAL/ISGRI light curve and confirmed through an epoch folding period search. Furthermore, the light curve allows us to determine a very strong spin up of -2x10(exp 4)h/h during the outburst. This spin up is confirmed by the pulse period evolution calculated from Swift/BAT data. The Swift/BAT data also show a long spin-down trend prior to the 2008 outburst. which is confirmed in archival INTEGRAL/ISGRI data. We discuss possible accretion models and geometries allowing for the transfer of such large amounts of angular momentum and investigate the harder spectrum of this outburst compared to previously published results.

  6. X-Ray Jet Emission from the Black Hole X-Ray Binary XTE J1550-564 with Chandra in 2000

    NASA Astrophysics Data System (ADS)

    Tomsick, John A.; Corbel, Stéphane; Fender, Rob; Miller, Jon M.; Orosz, Jerome A.; Tzioumis, Tasso; Wijnands, Rudy; Kaaret, Philip

    2003-01-01

    We have discovered an X-ray jet due to material ejected from the black hole X-ray transient XTE J1550-564. The discovery was first reported in 2002 by Corbel and coworkers, and here we present an analysis of the three Chandra observations made between 2000 June and September. For these observations, a source is present that moves in an eastward direction away from the point source associated with the compact object. The separation between the new source and the compact object changes from 21.3" in June to 23.4" in September, implying a proper motion of 21.2+/-7.2 mas day-1, a projected separation of 0.31-0.85 pc, and an apparent jet velocity between 0.34+/-0.12 and 0.93+/-0.32 times the speed of light for a source distance range of d=2.8-7.6 kpc. These observations represent the first time that an X-ray jet proper-motion measurement has been obtained for any accretion-powered Galactic or extragalactic source. While this work deals with the jet to the east of the compact object, the western jet has also been detected in the X-ray and radio bands. The most likely scenario is that the eastern jet is the approaching jet and that the jet material was ejected from the black hole in 1998. Along with a 1998 VLBI proper-motion measurement, the Chandra proper motion indicates that the eastern jet decelerated between 1998 and 2000. There is evidence that the eastern jet is extended by +/-2"-3" in the direction of the proper motion. The upper limit on the source extension in the perpendicular direction is +/-1.5", which corresponds to a jet opening angle of less than 7.5d. The X-ray jet energy spectrum is well but not uniquely described by a power law with an energy index of α=-0.8+/-0.4 (Sν~να) and interstellar absorption. The eastern jet was also detected in the radio band during an observation made within 7.4 days of the June Chandra observation. The overall radio flux level is consistent with an extrapolation of the X-ray power law with α=-0.6. The 0.3-8 keV X-ray jet

  7. The Pre-merger Impact Velocity of the Binary Cluster A1750 from X-Ray, Lensing, and Hydrodynamical Simulations

    NASA Astrophysics Data System (ADS)

    Molnar, Sandor M.; Chiu, I.-Non Tim; Broadhurst, Tom; Stadel, Joachim G.

    2013-12-01

    Since the discovery of the "Bullet Cluster," several similar cases have been uncovered that suggest relative velocities well beyond the tail of high speed collisions predicted by the concordance ΛCDM model. However, quantifying such post-merger events with hydrodynamical models requires a wide coverage of possible initial conditions. Here, we show that it is simpler to interpret pre-merger cases, such as A1750, where the gas between the colliding clusters is modestly affected, so that the initial conditions are clear. We analyze publicly available Chandra data confirming a significant increase in the projected X-ray temperature between the two cluster centers in A1750 consistent with our expectations for a merging cluster. We model this system with a self-consistent hydrodynamical simulation of dark matter and gas using the FLASH code. Our simulations reproduce well the X-ray data and the measured redshift difference between the two clusters in the phase before the first core passage viewed at an intermediate projection angle. The deprojected initial relative velocity derived using our model is 1460 km s-1, which is considerably higher than the predicted mean impact velocity for simulated massive haloes derived by recent ΛCDM cosmological simulations, but is within the allowed range. Our simulations demonstrate that such systems can be identified using a multi-wavelength approach and numerical simulations, for which the statistical distribution of relative impact velocities may provide a definitive examination of a broad range of dark matter scenarios.

  8. The pre-merger impact velocity of the binary cluster A1750 from X-ray, lensing, and hydrodynamical simulations

    SciTech Connect

    Molnar, Sandor M.; Chiu, I-Non Tim; Broadhurst, Tom; Stadel, Joachim G.

    2013-12-10

    Since the discovery of the 'Bullet Cluster', several similar cases have been uncovered that suggest relative velocities well beyond the tail of high speed collisions predicted by the concordance ΛCDM model. However, quantifying such post-merger events with hydrodynamical models requires a wide coverage of possible initial conditions. Here, we show that it is simpler to interpret pre-merger cases, such as A1750, where the gas between the colliding clusters is modestly affected, so that the initial conditions are clear. We analyze publicly available Chandra data confirming a significant increase in the projected X-ray temperature between the two cluster centers in A1750 consistent with our expectations for a merging cluster. We model this system with a self-consistent hydrodynamical simulation of dark matter and gas using the FLASH code. Our simulations reproduce well the X-ray data and the measured redshift difference between the two clusters in the phase before the first core passage viewed at an intermediate projection angle. The deprojected initial relative velocity derived using our model is 1460 km s{sup –1}, which is considerably higher than the predicted mean impact velocity for simulated massive haloes derived by recent ΛCDM cosmological simulations, but is within the allowed range. Our simulations demonstrate that such systems can be identified using a multi-wavelength approach and numerical simulations, for which the statistical distribution of relative impact velocities may provide a definitive examination of a broad range of dark matter scenarios.

  9. Probing the neutron star spin evolution in the young Small Magellanic Cloud Be/X-ray binary SXP 1062

    NASA Astrophysics Data System (ADS)

    Popov, S. B.; Turolla, R.

    2012-03-01

    The newly discovered Be/X-ray binary in the Small Magellanic Cloud, SXP 1062, provides the first example of a robust association with a supernova remnant (SNR). The short age estimated for the SNR qualifies SXP 1062 as the youngest known source in its class, ?. As such, it allows us to test current models of magnetorotational evolution of neutron stars in a still unexplored regime. Here we discuss possible evolutionary scenarios for SXP 1062 in an attempt to reconcile its long spin period, ?, and short age. Although several options can be considered, like an anomalously long initial period or the presence of a fossil disc, our results indicate that SXP 1062 may host a neutron star born with a large initial magnetic field, typically in excess of ˜ 1014 G, which then decayed to ˜ 1013 G.

  10. The Galactic distribution of X-ray binaries and its implications for compact object formation and natal kicks

    NASA Astrophysics Data System (ADS)

    Repetto, Serena; Igoshev, Andrei P.; Nelemans, Gijs

    2017-01-01

    The aim of this work is to study the imprints that different models for black hole (BH) and neutron star (NS) formation have on the Galactic distribution of X-ray binaries (XRBs) which contain these objects. We find that the root mean square of the height above the Galactic plane of BH- and NS-XRBs is a powerful proxy to discriminate among different formation scenarios, and that binary evolution following the BH/NS formation does not significantly affect the Galactic distributions of the binaries. We find that a population model in which at least some BHs receive a (relatively) high natal kick fits the observed BH-XRBs best. For the NS case, we find that a high NK distribution, consistent with the one derived from the measurement of pulsar proper motion, is the most preferable. We also analyse the simple method we previously used to estimate the minimal peculiar velocity of an individual BH-XRB at birth. We find that this method may be less reliable in the bulge of the Galaxy for certain models of the Galactic potential, but that our estimate is excellent for most of the BH-XRBs.

  11. DISCOVERY OF A SECOND TRANSIENT LOW-MASS X-RAY BINARY IN THE GLOBULAR CLUSTER NGC 6440

    SciTech Connect

    Heinke, C. O.; Budac, S. A.; Altamirano, D.; Linares, M.; Wijnands, R.; Cohn, H. N.; Lugger, P. M.; Servillat, M.; Grindlay, J. E.; Strohmayer, T. E.; Markwardt, C. B.; Swank, J. H.; Bailyn, C.

    2010-05-01

    We have discovered a new transient low-mass X-ray binary, NGC 6440 X-2, with Chandra/ACIS, RXTE/PCA, and Swift/XRT observations of the globular cluster NGC 6440. The discovery outburst (2009 July 28-31) peaked at L{sub X} {approx} 1.5 x 10{sup 36} erg s{sup -1} and lasted for <4 days above L{sub X} = 10{sup 35} erg s{sup -1}. Four other outbursts (2009 May 29-June 4, August 29-September 1, October 1-3, and October 28-31) have been observed with RXTE/PCA (identifying millisecond pulsations) and Swift/XRT (confirming a positional association with NGC 6440 X-2), with similar peak luminosities and decay times. Optical and infrared imaging did not detect a clear counterpart, with best limits of V>21, B>22 in quiescence from archival Hubble Space Telescope imaging, g'>22 during the August outburst from Gemini-South GMOS imaging, and J {approx_gt} 18.5 and K {approx_gt} 17 during the July outburst from CTIO 4 m ISPI imaging. Archival Chandra X-ray images of the core do not detect the quiescent counterpart (L{sub X} < (1-2) x 10{sup 31} erg s{sup -1}) and place a bolometric luminosity limit of L{sub NS} < 6 x 10{sup 31} erg s{sup -1} (one of the lowest measured) for a hydrogen atmosphere neutron star. A short Chandra observation 10 days into quiescence found two photons at NGC 6440 X-2's position, suggesting enhanced quiescent emission at L{sub X} {approx} 6 x 10{sup 31} erg s{sup -1}. NGC 6440 X-2 currently shows the shortest recurrence time ({approx}31 days) of any known X-ray transient, although regular outbursts were not visible in the bulge scans before early 2009. Fast, low-luminosity transients like NGC 6440 X-2 may be easily missed by current X-ray monitoring.

  12. A First Robust Measurement of the Aging of Field Low Mass X-ray Binary Populations from Hubble and Chandra

    NASA Astrophysics Data System (ADS)

    Lehmer, Bret

    Our understanding of X-ray binary (XRB) formation and evolution have been revolutionized by HST and Chandra by allowing us to study in detail XRBs in extragalactic environments. Theoretically, XRB formation is sensitive to parent stellar population properties like metallicity and stellar age. These dependencies not only make XRBs promising populations for aiding in the measurement of galaxy properties themselves, but also have important astrophysical implications. For example, due to the relatively young stellar ages and primordial metallicities in the early Universe (z > 3), it is predicted that XRBs were more luminous than today and played a significant role in the heating of the intergalactic medium. Unlocking the potential of XRBs as useful probes of galaxy properties and understanding in detail their evolutionary pathways critically requires empirical constraints using well-studied galaxies that span a variety of evolutionary stages. In this ADAP, we will use the combined power of archival observations from Hubble and Chandra data of 16 nearby early-type galaxies to study how low-mass XRBs (LMXBs) populations evolve with age. LMXBs are critically important since they are the most numerous XRBs in the MW and are expected to dominate the normal galaxy Xray emissivity of the Universe out to z ~ 2. Understanding separately LMXBs that form via dynamical interactions (e.g., in globular clusters; GCs) versus those that form in-situ in galactic fields is an important poorly constrained area of XRB astrophysics. We are guided by the following key questions: 1. How does the shape and normalization of the field LMXB X-ray luminosity function (XLF) evolve as parent stellar populations age? Using theoretical population synthesis models, what can we learn about the evolution of contributions from various LMXB donor stars (e.g., red-giant, main-sequence, and white dwarf donors)? 2. Is there any evidence that globular cluster (GC) LMXBs seeded field LMXB populations through

  13. Erratum: ``Some Constraints on the Effect of Age and Metallicity on the Low-Mass X-Ray Binary Formation Rate'' (ApJ, 589, L81 [2003])

    NASA Astrophysics Data System (ADS)

    Kundu, Arunav; Maccarone, Thomas J.; Zepf, Stephen E.; Puzia, Thomas H.

    2004-01-01

    The number of low-mass X-ray binaries in NGC 4365 that are within 0.5" of a globular cluster and considered to be matches is 18, not 23 as mistakenly reported in the first paragraph of § 3. The correct number is used elsewhere in the above Letter. The fraction of low-mass X-ray binaries that are associated with globular clusters in NGC 4365 is indeed 40% as noted later in the same paragraph. We thank W. Lewin for alerting us to this error.

  14. The Orbit and Properties of the BD+60 73 + IGRJ00370+612 Supergiant X-Ray Binary

    NASA Astrophysics Data System (ADS)

    Bolton, C. T.; Grunhut, J. H.

    2007-08-01

    Spectrograms of the blue and H alpha regions of BD+60 73 obtained with the Cassegrain spectrograph on the David Dunlap Observatory 1.88 m telescope have been measured for radial velocities. These measures confirm that BD+60 73 is a single-line spectroscopic binary with the same period, 15.665 d, as the x-ray flux variations of IGRJ00370+612. The x-ray maxima occur at or just after the time of periastron passage, even though the eccentricity e=0.37 does not seem large enough to produce a large increase in the mass flux at the position of the compact object at the time of periastron passage. The mass function combined with a plausible range of possible masses for a neutron star companion yields primary masses within the range expected for the spectral type of BD+60 73. The compact companion cannot be a black hole unless the supergiant has an exceptionally high mass for its B1Ib spectral type or the inclination of the orbit is very low. The H alpha line shows weak, variable emission, but we have insufficient data to test whether these variations are correlated with orbital phase. We note, as have other authors, that BD+60_73 is projected on the sky within the bounds of Cas OB5. It also lies close to the "adolescent" supernova remnant CTB1. However, the binary system has a radial velocity of approximately -40 km/s with respect to Cas OB5.

  15. STOCHASTIC VARIABILITY IN X-RAY EMISSION FROM THE BLACK HOLE BINARY GRS 1915+105

    SciTech Connect

    Polyakov, Yuriy S.; Neilsen, Joseph; Timashev, Serge F.

    2012-06-15

    We examine stochastic variability in the dynamics of X-ray emission from the black hole system GRS 1915+105, a strongly variable microquasar commonly used for studying relativistic jets and the physics of black hole accretion. The analysis of sample observations for 13 different states in both soft (low) and hard (high) energy bands is performed by flicker-noise spectroscopy (FNS), a phenomenological time series analysis method operating on structure functions and power spectrum estimates. We find the values of FNS parameters, including the Hurst exponent, flicker-noise parameter, and characteristic timescales, for each observation based on multiple 2500 s continuous data segments. We identify four modes of stochastic variability driven by dissipative processes that may be related to viscosity fluctuations in the accretion disk around the black hole: random (RN), power-law (1F), one-scale (1S), and two-scale (2S). The variability modes are generally the same in soft and hard energy bands of the same observation. We discuss the potential for future FNS studies of accreting black holes.

  16. Discovery of Nearly Coherent Oscillations with a Frequency of approximately 567 Hz During Type I X-ray Bursts of the X-ray Transient and Eclipsing Binary X1658-298

    NASA Technical Reports Server (NTRS)

    Wijnands, Rudy; Strohmayer, Tod; Franco, Lucia M.; White, Nicholas E. (Technical Monitor)

    2001-01-01

    We report the discovery of nearly coherent oscillations with a frequency of approximately 567 Hz during type I X-ray bursts from the X-ray transient and eclipsing binary X1658-298. If these oscillations are directly related to the neutron star rotation, then the spin period of the neutron star in X1658-298 is approximately 1.8 ms. The oscillations can be present during the rise or decay phase of the bursts. Oscillations during the decay phase of the bursts show an increase in frequency of approximately 0.5-1 Hz. However, in one particular burst the oscillations reappear at the end of the decay phase at about 571.5 Hz. This represents an increase in oscillation frequency of about 5 Hz, which is the largest frequency change seen so far in a burst oscillation. It is unclear if such a large change can be accommodated by present models used to explain the frequency evolution of the oscillations. The oscillations at 571.5 Hz are unusually soft compared to the oscillations found at 567 Hz. We also observed several bursts during which the oscillations are detected at much lower significance or not at all. Most of these bursts happen during periods of X-ray dipping behavior, suggesting that the X-ray dipping might decrease the amplitude of the oscillations (although several complications exist with this simple picture). We discuss our discovery in the framework of the neutron star spin interpretation.

  17. SXP 1062, a young Be X-ray binary pulsar with long spin period. Implications for the neutron star birth spin

    NASA Astrophysics Data System (ADS)

    Haberl, F.; Sturm, R.; Filipović, M. D.; Pietsch, W.; Crawford, E. J.

    2012-01-01

    Context. The Small Magellanic Cloud (SMC) is ideally suited to investigating the recent star formation history from X-ray source population studies. It harbours a large number of Be/X-ray binaries (Be stars with an accreting neutron star as companion), and the supernova remnants can be easily resolved with imaging X-ray instruments. Aims: We search for new supernova remnants in the SMC and in particular for composite remnants with a central X-ray source. Methods: We study the morphology of newly found candidate supernova remnants using radio, optical and X-ray images and investigate their X-ray spectra. Results: Here we report on the discovery of the new supernova remnant around the recently discovered Be/X-ray binary pulsar CXO J012745.97-733256.5 = SXP 1062 in radio and X-ray images. The Be/X-ray binary system is found near the centre of the supernova remnant, which is located at the outer edge of the eastern wing of the SMC. The remnant is oxygen-rich, indicating that it developed from a type Ib event. From XMM-Newton observations we find that the neutron star with a spin period of 1062 s (the second longest known in the SMC) shows a very high average spin-down rate of 0.26 s per day over the observing period of 18 days. Conclusions: From the currently accepted models, our estimated age of around 10 000-25 000 years for the supernova remnant is not long enough to spin down the neutron star from a few 10 ms to its current value. Assuming an upper limit of 25 000 years for the age of the neutron star and the extreme case that the neutron star was spun down by the accretion torque that we have measured during the XMM-Newton observations since its birth, a lower limit of 0.5 s for the birth spin period is inferred. For more realistic, smaller long-term average accretion torques our results suggest that the neutron star was born with a correspondingly longer spin period. This implies that neutron stars in Be/X-ray binaries with long spin periods can be much younger

  18. Broad-band spectroscopy of the transient X-ray binary pulsar KS 1947+300 during 2013 giant outburst: Detection of pulsating soft X-ray excess component

    NASA Astrophysics Data System (ADS)

    Epili, Prahlad; Naik, Sachindra; Jaisawal, Gaurava K.

    2016-05-01

    We present the results obtained from detailed timing and spectral studies of the Be/X-ray binary pulsar KS 1947+300 during its 2013 giant outburst. We used data from Suzaku observations of the pulsar at two epochs, i.e. on 2013 October 22 (close to the peak of the outburst) and 2013 November 22. X-ray pulsations at ˜18.81 s were clearly detected in the light curves obtained from both observations. Pulse periods estimated during the outburst showed that the pulsar was spinning up. The pulse profile was found to be single-peaked up to ˜10 keV beyond which a sharp peak followed by a dip-like feature appeared at hard X-rays. The dip-like feature has been observed up to ˜70 keV. The 1-110 keV broad-band spectroscopy of both observations revealed that the best-fit model was comprised of a partially absorbed Negative and Positive power law with EXponential cutoff (NPEX) continuum model along with a blackbody component for the soft X-ray excess and two Gaussian functions at 6.4 and 6.7 keV for emission lines. Both the lines were identified as emission from neutral and He-like iron atoms. To fit the spectra, we included the previously reported cyclotron absorption line at 12.2 keV. From the spin-up rate, the magnetic field of the pulsar was estimated to be ˜1.2×1012 G and found to be comparable to that obtained from the detection of the cyclotron absorption feature. Pulse-phase resolved spectroscopy revealed the pulsating nature of the soft X-ray excess component in phase with the continuum flux. This confirms that the accretion column and/or accretion stream are the most probable regions of the soft X-ray excess emission in KS1947+300. The presence of the pulsating soft X-ray excess in phase with continuum emission may be the possible reason for not observing the dip at soft X-rays.

  19. First Detection of Phase-dependent Colliding Wind X-ray Emission outside the Milky Way

    NASA Technical Reports Server (NTRS)

    Naze, Yael; Koenigsberger, Gloria; Moffat, Anthony F. J.

    2007-01-01

    After having reported the detection of X-rays emitted by the peculiar system HD 5980, we assess here the origin of this high-energy emission from additional X-ray observations obtained with XMM-Newton. This research provides the first detection of apparently periodic X-ray emission from hot gas produced by the collision of winds in an evolved massive binary outside the Milky Way. It also provides the first X-ray monitoring of a Luminous Blue Variable only years after its eruption and shows that the source of the X-rays is not associated with the ejecta.

  20. Evidence for variable, correlated X-ray and optical/IR extinction towards the nearby, pre-main-sequence binary TWA 30

    NASA Astrophysics Data System (ADS)

    Principe, David A.; Sacco, G.; Kastner, J. H.; Stelzer, B.; Alcalá, J. M.

    2016-06-01

    We present contemporaneous XMM-Newton X-ray and ground-based optical/near-IR spectroscopic observations of the nearby (D ≈ 42 pc), low-mass (mid-M) binary system TWA 30A and 30B. The components of this wide (separation ˜3400 au) binary are notable for their nearly edge-on disc viewing geometries, high levels of variability, and evidence for collimated stellar outflows. We obtained XMM-Newton X-ray observations of TWA 30A and 30B in 2011 June and July, accompanied (respectively) by Infrared Telescope Facility SpeX (near-IR) and VLT XSHOOTER (visible/near-IR) spectroscopy obtained within ˜20 h of the X-ray observations. TWA 30A was detected in both XMM-Newton observations at relatively faint intrinsic X-ray luminosities (LX ˜ 8 × 1027 erg s-1) compared to stars of similar mass and age. The intrinsic (0.15-2.0 keV) X-ray luminosities measured in 2011 had decreased by a factor 20-100 relative to a 1990 (ROSAT) X-ray detection. TWA 30B was not detected, and we infer an upper limit on its X-ray Luminosity of LX ≲ 3.0 × 1027 erg s-1. We measured a decrease in visual extinction towards TWA 30A (from AV ≈ 14.9 to AV ≈ 4.7) between the two 2011 observing epochs, and we find evidence for a corresponding significant decrease in X-ray absorbing column (NH). The apparent correlated change in AV and NH is suggestive of variable obscuration of the stellar photosphere by disc material composed of both gas and dust. However, in both observations, the inferred NH to AV ratio is lower than that typical of the interstellar medium, suggesting that the disc is either depleted of gas or is deficient in metals in the gas phase.

  1. Application of the Ghosh & Lamb Relation to the Spin-up/down Behavior in the X-ray Binary Pulsar 4U 1626-67

    NASA Astrophysics Data System (ADS)

    Takagi, Toshihiro; Mihara, Tatehiro; Sugizaki, Mutsumi; Makishima, Kazuo; Morii, Mikio

    Using the relation proposed by Ghosh & Lamb (1979) between the pulse-period derivative and the X-ray luminosity in binary X-ray pulsars, we tried to constrain the mass and radius of a neutron star. To apply the relation to the binary X-ray pulsar 4U 1626-67, we compiled previous measurements of its period, period derivative, and flux, and added measurements with the MAXI/GSC onboard the International Space Station. The measured period derivative was tightly correlated with the flux, and the relation is successfully explained by the Ghosh & Lamb relation. We found that an assumed distance of, e.g., 8 kpc, gives a mass of 1.39-1.46 solar mass, and a radius as 11.9-12.0 km. This method thus provides a valuable tool to constrain these parameters, even though we need to precisely know the distance [2].

  2. Probing the Masses and Radii of Donor Stars in Eclipsing X-Ray Binaries with the Swift Burst Alert Telescope

    NASA Astrophysics Data System (ADS)

    Coley, Joel B.; Corbet, Robin H. D.; Krimm, Hans A.

    2015-08-01

    Physical parameters of both the mass donor and compact object can be constrained in X-ray binaries with well-defined eclipses, as our survey of wind-fed supergiant X-ray binaries IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016, and XTE J1855-026 reveals. Using the orbital period and Kepler’s third law, we express the eclipse half-angle in terms of radius, inclination angle, and the sum of the masses. Pulse-timing and radial velocity curves can give masses of both the donor and compact object as in the case of the “double-lined” binaries IGR J18027-2016 and XTE J1855-026. The eclipse half angles are {15}-2+3, {31.7}-0.8+0.7, 32 ± 2,34 ± 2, and 33.6+/- 0.7 degrees for IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016, and XTE 1855-026, respectively. In wind-fed systems, the primary not exceeding the Roche-lobe size provides an upper limit on system parameters. In IGR J16393-4643, spectral types of B0 V or B0-5 III are found to be consistent with the eclipse duration and Roche-lobe, but the previously proposed donor stars in IGR J16418-4532 and IGR J16479-4514 were found to be inconsistent with the Roche-lobe size. Stars with spectral types O7.5 I and earlier are possible. For IGR J18027-2016, the mass and radius of the donor star lie between 18.6-19.4 {M}⊙ and 17.4-19.5 {R}⊙ . We constrain the neutron star mass between 1.37 and 1.43 {M}⊙ .We find the mass and radius of the donor star in XTE J1855-026 to lie between 19.6-20.2 {M}⊙ and 21.5-23.0 {R}⊙ . The neutron star mass was constrained to 1.77-1.82 {M}⊙ . Eclipse profiles are asymmetric in IGR J18027-2016 and XTE J1855-026, which we attribute to accretion wakes.

  3. EVIDENCE FOR A CONSTANT IMF IN EARLY-TYPE GALAXIES BASED ON THEIR X-RAY BINARY POPULATIONS

    NASA Astrophysics Data System (ADS)

    Zepf, Stephen E.; Maccarone, T. J.; Kundu, A.; Gonzalez, A. H.; Lehmer, B.; Maraston, C.

    2014-01-01

    A number of recent studies have proposed that the stellar initial mass function (IMF) of early type galaxies varies systematically as a function of galaxy mass, with higher mass galaxies having steeper IMFs. These steeper IMFs have more low-mass stars relative to the number of high mass stars, and therefore naturally result in proportionally fewer neutron stars and black holes. In this paper, we specifically predict the variation in the number of black holes and neutron stars in early type galaxies based on the IMF variation required to reproduce the observed mass-to-light ratio trends with galaxy mass. We then test whether such variations are observed by studying the field low-mass X-ray binary populations (LMXBs) of nearby early-type galaxies. These binaries are field neutron stars or black holes accreting from a low-mass donor star. We specifically compare the number of field LMXBs per K-band light in a well-studied sample of elliptical galaxies, and use this result to distinguish between an invariant IMF and one that is Kroupa/Chabrier-like at low masses and steeper at high masses. We discuss how these observations constrain the possible forms of the IMF variations and how future Chandra observations can enable sharper tests of the IMF.

  4. Limits of visual detection for finasteride polymorphs in prepared binary mixtures: analysis by X-ray powder diffraction.

    PubMed

    Bezzon, Vinícius D N; Antonio, Selma G; Paiva-Santos, Carlos O

    2014-11-01

    Finasteride (FNT) is a drug that inhibits human enzyme type II 5α-reductase that metabolizes testosterone into dihydrotestosterone. There are two enantiotropic polymorphs with known crystal structure: designated as forms I and II. Identification and control of these polymorphic forms in mixtures can be performed using X-ray powder diffraction (XRPD) data and Rietveld method (RM). As experimental conditions may limit the detection of minority phases in mixtures, it is interesting to show what are these limits for some usual and one high-resolution equipment. So, in this work, we discuss the parameters to find the limit of the detection in binary mixtures of forms I and II of FNT according to each experimental condition. The samples analyzed were binary mixtures prepared with anhydrous polymorphs of the drug FNT. These samples were measured in four diffractometers with different experimental condition. These equipments represent the main resolutions generally used for drug analysis by XRPD. For the development of this work, a batch of form I was obtained pure, and another batch with forms I and II was used to obtain pure form II by heat treatment. Depending on the experimental condition, the polymorphs could be detected in a proportion as low as 0.5 wt%. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3567-3575, 2014.

  5. On the Optical-X-Ray Correlation from Outburst to Quiescence in Low-mass X-Ray Binaries: The Representative Cases of V404 Cyg and Cen X-4

    NASA Astrophysics Data System (ADS)

    Bernardini, F.; Russell, D. M.; Kolojonen, K. I. I.; Stella, L.; Hynes, R. I.; Corbel, S.

    2016-08-01

    Low-mass X-ray binaries (LMXBs) show evidence of a global correlation of debated origin between X-ray and optical luminosity. We study for the first time this correlation in two transient LMXBs, the black hole (BH) V404 Cyg and the neutron star Cen X-4, over six orders of magnitude in X-ray luminosity, from outburst to quiescence. After subtracting the contribution from the companion star, the Cen X-4 data can be described by a single power-law correlation of the form {L}{opt}\\propto {L}{{X}}0.44, consistent with disk reprocessing. We find a similar correlation slope for V404 Cyg in quiescence (0.46) and a steeper one (0.56) in the outburst hard state of 1989. However, V404 Cyg is about 160-280 times optically brighter, at a given 3-9 keV X-ray luminosity, compared to Cen X-4. This ratio is a factor of 10 smaller in quiescence, where the normalization of the V404 Cyg correlation also changes. Once the bolometric X-ray emission is considered and the known main differences between V404 Cyg and Cen X-4 are taken into account (a larger compact object mass, accretion disk size, and the presence of a strong jet contribution in the hard state for the BH system), the two systems lie on the same correlation. In V404 Cyg, the jet dominates spectrally at optical-infrared frequencies during the hard state but makes a negligible contribution in quiescence, which may account for the change in its correlation slope and normalization. These results provide a benchmark to compare with data from the 2015 outburst of V404 Cyg and, potentially, other transient LMXBs as well.

  6. The mass of the black hole in the X-ray binary LMC X-1

    NASA Astrophysics Data System (ADS)

    Abubekerov, M. K.; Antokhina, E. A.; Gostev, N. Yu.; Cherepashchuk, A. M.; Shimansky, V. V.

    2016-12-01

    A dynamical estimate of the mass of the black hole in the LMC X-1 binary system is obtained in the framework of a Roche model for the optical star, based on fitting of the He I 4471 Å and He II 4200 Å absorption lines assuming LTE. The mass of the black hole derived from the radial-velocity curve for the He II 4200 Å line is m x = 10.55 M ⊙, close to the value found earlier based on a model with two point bodies [1].

  7. Soft x-ray properties of the binary millisecond pulsar J0437-4715

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Martin, Christopher; Marshall, Herman L.

    1995-01-01

    We obtained a light curve for the 5.75 ms pulsar J0437-4715 in the 65-120 A range with 0.5 ms time resolution using the Deep Survey instrument on the EUVE satellite. The single-peaked profile has a pulsed fraction of 0. 27 +/- 0.05, similar to the ROSAT data in the overlapping energy band. A combined analysis of the EUVE and ROSAT data is consistent with a power-law spectrum of energy index alpha = 1.2-1.5, intervening column density NH = (5-8) x 10(exp 19)/sq cm, and luminosity 5.0 x 10(exp 30) ergs/s in the 0.1-2. 4 keV band. We also use a bright EUVE/ROSAT source only 4.3 deg from the pulsar, the Seyfert galaxy RX J0437.4-4711 (= EUVE J0437-471 = lES 0435-472), to obtain an independent upper limit on the intervening absorption to the pulsar, NH less than 1.2 x 10(exp 20)/sq cm. Although a blackbody spectrum fails to fit the ROSAT data, two-component spectral fits to the combined EUVE/ROSAT data are used to limit the temperatures and surface areas of thermal emission that might make partial contributions to the flux. A hot polar cap of radius 50-600 m and temperature (1.0-3.3) x 10(exp 6) K could be present. Alternatively, a larger region with T = (4-12) x 10(exp 5) K and area less than 200 sq km, might contribute most of the EUVE and soft X-ray flux, but only if a hotter component were present as well. Any of these temperatures would require some mechanism(s) of surface reheating to be operating in this old pulsar, the most plausible being the impact of accelerated electrons and positrons onto the polar caps. The kinematically corrected spin-down power of PSR J0437-4715 is only 4 x 10(exp 33) ergs/s, which is an order of magnitude less than that of the lowest-luminosity gamma-ray pulsars Geminga and PSR B1055-52. The absence of high-energy gamma-rays from PSR J0437-4715 might signify an inefficient or dead outer gap accelerator, which in turn accounts for the lack of a more luminous reheated surface such as those intermediate-age gamma-ray pulsars may have.

  8. Soft X-Ray Properties of the Binary Millisecond Pulsar J0437-4715

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Martin, Christopher; Marshall, Herman, L.; Oliversen, Ronald (Technical Monitor)

    2001-01-01

    We obtained a light curve for the 5.75 ms pulsar J0437-4715 in the 65-120 A range with 0.5 ms time resolution using the Deep Survey instrument on the EUVE satellite. The single-peaked profile has a pulsed fraction of 0.27 +/- 0.05, similar to the ROSAT data in the overlapping energy band. A combined analysis of the EUVE and ROSAT data is consistent with a power-law spectrum of energy index alpha = 1.2 - 1.5, intervening column density N(sub H) = (5 - 8) x 10(exp 19)/sq cm, and luminosity 5.0 x 10(exp 30) ergs/s in the 0.1 - 2.4 keV band. We also use a bright EUVE/ROSAT source only 4.2 min. from the pulsar, the Seyfert galaxy RX J0437.4-4711 (= EUVE J0437-471 = IES 0435-472), to obtain an independent upper limit on the intervening absorption to the pulsar, N(sub H) less than 1.2 x 10(exp 20)/sq cm. Although a blackbody spectrum fails to fit the ROSAT data, two-component spectral fits to the combined EUVE/ROSAT data are used to limit the temperatures and surface areas of thermal emission that might make partial contributions to the flux. A hot polar cap of radius 50 - 600 m and temperature (1.0 - 3.3) x 10(exp 6) K could be present. Alternatively, a larger region with T = (4 - 12) x 10(exp 5) K and area less than 200 sq km, might contribute most of the EUVE and soft X-ray flux, but only if a hotter component were present as well. Any of these temperatures would require some mechanism(s) of surface reheating to be operating in this old pulsar, the most plausible being the impact of accelerated electrons and positrons onto the polar caps. The kinematically corrected spin-down power of PSR J0437-4715 is only 4 x 10(exp 33) ergs/s, which is an order of magnitude less than that of the lowest-luminosity gamma-ray pulsars Geminga and PSR B1055-52. The absence of high-energy gamma-rays from PSR J0437-4715 might signify an inefficient or dead outer gap accelerator, which in turn accounts for the lack of a more luminous reheated surface such as those intermediate-age gamma

  9. The End of Accretion: The X-Ray Binary/Millisecond Pulsar Transition Object PSR J1023+0038

    NASA Astrophysics Data System (ADS)

    Archibald, Anne

    2015-04-01

    Millisecond radio pulsars (MSRPs), those spinning hundreds of times per second, have long been understood to be old pulsars that have been spun up by the accretion of matter from a companion in a low-mass X-ray binary (LMXB) phase. Yet the details of this transformation, particularly the end of the accretion process and the birth of a radio pulsar, remain mysterious. I will describe the discovery and detailed study of the first object known to transition between MSRP and LMXB states, PSR J1023+0038. By dint of a multiwavelength campaign of observations in the RMSP state, we are able to measure all the key system parameters and show the existence of an X-ray shock close to the pulsar-facing side of the companion. Since the discovery of PSR J1023+0038, two more objects (XSS J12270-4859 and M28I) have been found to make the same transition, and the study of these transitioning objects has become an active field of research. Most interestingly, PSR J1023+0038 has transitioned back into an LMXB state, with an active accretion disk and a puzzling increase in gamma-ray flux. Our detailed picture of the system allows us to test models of accretion against the phenomena we observe in PSR J1023+0038, and in fact these observations challenge current models: in spite of the low luminosity of the system (and low inferred accretion rate) some material is penetrating the centrifugal barrier and falling on the neutron-star surface. Key evidence for explaining this puzzling behaviour will come when PSR J1023+0038 returns to an MSRP state and we are able to compare pulsar timing models from after the LMXB state with those we obtained in this work.

  10. Upper Bounds on r-Mode Amplitudes from Observations of Low-Mass X-Ray Binary Neutron Stars

    NASA Technical Reports Server (NTRS)

    Mahmoodifar, Simin; Strohmayer, Tod

    2013-01-01

    We present upper limits on the amplitude of r-mode oscillations and gravitational-radiation-induced spin-down rates in low-mass X-ray binary neutron stars, under the assumption that the quiescent neutron star luminosity is powered by dissipation from a steady-state r-mode. For masses <2M solar mass we find dimensionless r-mode amplitudes in the range from about 1×10(exp-8) to 1.5×10(exp-6). For the accreting millisecond X-ray pulsar sources with known quiescent spin-down rates, these limits suggest that approx. less than 1% of the observed rate can be due to an unstable r-mode. Interestingly, the source with the highest amplitude limit, NGC 6440, could have an r-mode spin-down rate comparable to the observed, quiescent rate for SAX J1808-3658. Thus, quiescent spin-down measurements for this source would be particularly interesting. For all sources considered here, our amplitude limits suggest that gravitational wave signals are likely too weak for detection with Advanced LIGO. Our highest mass model (2.21M solar mass) can support enhanced, direct Urca neutrino emission in the core and thus can have higher r-mode amplitudes. Indeed, the inferred r-mode spin-down rates at these higher amplitudes are inconsistent with the observed spin-down rates for some of the sources, such as IGR J00291+5934 and XTE J1751-305. In the absence of other significant sources of internal heat, these results could be used to place an upper limit on the masses of these sources if they were made of hadronic matter, or alternatively it could be used to probe the existence of exotic matter in them if their masses were known.

  11. Suzaku monitoring of hard X-ray emission from η Carinae over a single binary orbital cycle

    SciTech Connect

    Hamaguchi, Kenji; Corcoran, Michael F.; Yuasa, Takayuki; Ishida, Manabu; Pittard, Julian M.; Russell, Christopher M. P.

    2014-11-10

    The Suzaku X-ray observatory monitored the supermassive binary system η Carinae 10 times during the whole 5.5 yr orbital cycle between 2005 and 2011. This series of observations presents the first long-term monitoring of this enigmatic system in the extremely hard X-ray band between 15 and 40 keV. During most of the orbit, the 15-25 keV emission varied similarly to the 2-10 keV emission, indicating an origin in the hard energy tail of the kT ∼ 4 keV wind-wind collision (WWC) plasma. However, the 15-25 keV emission declined only by a factor of three around periastron when the 2-10 keV emission dropped by two orders of magnitude due probably to an eclipse of the WWC plasma. The observed minimum in the 15-25 keV emission occurred after the 2-10 keV flux had already recovered by a factor of ∼3. This may mean that the WWC activity was strong, but hidden behind the thick primary stellar wind during the eclipse. The 25-40 keV flux was rather constant through the orbital cycle, at the level measured with INTEGRAL in 2004. This result may suggest a connection of this flux component to the γ-ray source detected in this field. The helium-like Fe Kα line complex at ∼6.7 keV became strongly distorted toward periastron as seen in the previous cycle. The 5-9 keV spectra can be reproduced well with a two-component spectral model, which includes plasma in collision equilibrium and a plasma in non-equilibrium ionization (NEI) with τ ∼ 10{sup 11} cm{sup –3} s{sup –1}. The NEI plasma increases in importance toward periastron.

  12. A global study of type B quasi-periodic oscillation in black hole X-ray binaries

    NASA Astrophysics Data System (ADS)

    Gao, H. Q.; Zhang, Liang; Chen, Yupeng; Zhang, Zhen; Chen, Li; Zhang, Shuang-Nan; Zhang, Shu; Ma, Xiang; Li, Zi-Jian; Bu, Qing-Cui; Qu, JinLu

    2017-04-01

    We performed a global study on the timing and spectral properties of type-B quasi-periodic oscillations (QPOs) in the outbursts of black hole X-ray binaries. The sample is built based on the observations of Rossi X-ray Timing Explorer (RXTE), via searching in the literature in RXTE era for all the identified type-B QPOs. To enlarge the sample, we also investigated some type-B QPOs that are reported but not yet fully identified. Regarding to the time lag and hard/soft flux ratio, we found that the sources with type-B QPOs behave in two subgroups. In one subgroup, type-B QPO shows a hard time lag that first decreases and then reverse into a soft time lag along with softening of the energy spectrum. In the other subgroup, type-B QPOs distribute only in a small region with hard time lag and relatively soft hardness. These findings may be understood with a diversity of the homogeneity showing up for the hot inner flow of different sources. We confirm the universality of a positive relation between the type-B QPO frequency and the hard component luminosity in different sources. We explain the results by considering that the type-B QPO photons are produced in the inner accretion flow around the central black hole, under a local Eddington limit. Using this relationship, we derived a mass estimation of 9.3-27.1 M⊙ for the black hole in H 1743-322.

  13. An examination of black hole binaries using X-ray observations and the development of the Bragg reflection polarimeter

    NASA Astrophysics Data System (ADS)

    Allured, Ryan

    Black hole binaries (BHBs) consist of a black hole which accretes matter from a companion star and emits radiation primarily in the X-ray band. They are known to evolve through various states of emission, which are believed to signify changes in the accretion geometry. MAXI J1659--152 is a recently discovered galactic BHB, and we used Rossi X-ray Timing Explorer (RXTE) observations to investigate its state evolution during its 2010 outburst. This evolution was found to be similar to that of other known BHBs, although its thermal spectral component was relatively weak. The data was also used to estimate the black hole mass to be 3.6--8.0 solar masses. Archival RXTE and Swift data were used to examine another BHB known as GX 339--4 in its faint, hard emission state. This source has a persistent iron line in its spectrum throughout its various emission states, and it is frequently used to estimate the inner radius of its accretion disk. The data were unable to constrain the inner radius through the modeling of the iron line, but estimates based on modeling of the thermal spectral component proved to be consistent with an increase in inner radius at low luminosities. Theoretical predictions of the soft X-ray polarization of BHBs indicate a change in both angle and magnitude with energy. The details of this change depend on both the spin and mass of the black hole. The NASA Gravity and Extreme Magnetism Small Explorer (GEMS) mission sought to use this effect to measure the spin of BHBs, which is necessary to develop tests of the Kerr metric in general relativity. The Bragg Reflection Polarimeter (BRP) was the student experiment on this mission, and was in the beginning stages of flight fabrication at the time of the mission's cancellation in May 2012. A prototype multilayer reflector meeting nearly all requirements was developed and its performance measured at a synchrotron beamline. Monte-Carlo simulations were carried out to estimate the ultimate polarization

  14. Long-term TeV and X-ray observations of the gamma-ray binary HESS J0632+057

    SciTech Connect

    Aliu, E.; Errando, M.; Archambault, S.; Aune, T.; Behera, B.; Chen, X.; Beilicke, M.; Buckley, J. H.; Bugaev, V.; Benbow, W.; Cerruti, M.; Berger, K.; Bird, R.; Bouvier, A.; Byrum, K.; Ciupik, L.; Connolly, M. P.; Cui, W.; Duke, C.; Dumm, J. E-mail: afalcone@astro.psu.edu; Collaboration: VERITAS Collaboration; H.E.S.S. Collaboration; and others

    2014-01-10

    HESS J0632+057 is the only gamma-ray binary known so far whose position in the sky allows observations with ground-based observatories in both the northern and southern hemispheres. Here we report on long-term observations of HESS J0632+057 conducted with the Very Energetic Radiation Imaging Telescope Array System and High Energy Stereoscopic System Cherenkov telescopes and the X-ray satellite Swift, spanning a time range from 2004 to 2012 and covering most of the system's orbit. The very-high-energy (VHE) emission is found to be variable and is correlated with that at X-ray energies. An orbital period of 315{sub −4}{sup +6} days is derived from the X-ray data set, which is compatible with previous results, P = (321 ± 5) days. The VHE light curve shows a distinct maximum at orbital phases close to 0.3, or about 100 days after periastron passage, which coincides with the periodic enhancement of the X-ray emission. Furthermore, the analysis of the TeV data shows for the first time a statistically significant (>6.5σ) detection at orbital phases 0.6-0.9. The obtained gamma-ray and X-ray light curves and the correlation of the source emission at these two energy bands are discussed in the context of the recent ephemeris obtained for the system. Our results are compared to those reported for other gamma-ray binaries.

  15. Long-term TeV and X-Ray Observations of the Gamma-Ray Binary HESS J0632+057

    NASA Astrophysics Data System (ADS)

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