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Sample records for binary circinus x-1

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. The Return of the Bursts : Thermonuclear Flashes from Circinus X-1

    NARCIS (Netherlands)

    Linares, M.; Watts, A.; Altamirano, D.; Soleri, P.; Degenaar, N.; Yang, Y.; Wijnands, R.; Casella, P.; Homan, J.; Chakrabarty, D.; Rea, N.; Armas-Padilla, M.; Cavecchi, Y.; Kalamkar, M.; Kaur, R.; Patruno, A.; van der Klis, M.

    We report the detection of 15 X-ray bursts with RXTE and Swift observations of the peculiar X-ray binary Circinus X-1 (Cir X-1) during its 2010 May X-ray re-brightening. These are the first X-ray bursts observed from the source after the initial discovery by Tennant and collaborators, 25 years ago.

  3. The nature of the companion star in Circinus X-1

    Science.gov (United States)

    Johnston, Helen M.; Soria, Roberto; Gibson, Joel

    2016-02-01

    We present optical spectra and images of the X-ray binary Circinus X-1. The optical light curve of Cir X-1 is strongly variable, changing in brightness by 1.2 mag in the space of four days. The shape of the light curve is consistent with that seen in the 1980s, when the X-ray and radio counterparts of the source were at least ten times as bright as they are currently. We detect strong, variable H α emission lines, consisting of multiple components which vary with orbital phase. We estimate the extinction to the source from the strength of the diffuse interstellar bands and the Balmer decrement; the two methods give AV = 7.6 ± 0.6 mag and AV > 9.1 mag, respectively. The optical light curve can be modelled as arising from irradiation of the companion star by the central X-ray source, where a low-temperature star fills its Roche lobe in an orbit of moderate eccentricity (e ˜ 0.4). We suggest that the companion star is overluminous and underdense, due to the impact of the supernova which occurred less than 5000 yr ago.

  4. RXTE detects X-ray bursts from Circinus X-1

    NARCIS (Netherlands)

    Linares, M.; Soleri, P.; Watts, A.; Altamirano, D.; Armas-Padilla, M.; Cavecchi, Y.; Degenaar, N.; Kalamkar, M.; Kaur, R.; van der Klis, M.; Patruno, A.; Wijnands, R.; Yang, Y.; Casella, P.; Rea, N.

    After the recent report of X-ray re-brightening (ATel #2608), RXTE has observed the peculiar neutron star X-ray binary Cir X-1 eleven times during the last two weeks (May 11-25, 2010). We report the detection of nine X-ray bursts in RXTE-PCA data, 25 years after the first -and the only previous-

  5. Optical and radio counterpart of Circinus X-1 (3U 1516-56)

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, J A.J.; Murdin, P G; Peterson, B A [Anglo-Australian Observatory, Epping (Australia); and others

    1977-11-01

    Circinus X-1 (3U 1516-56) has a radio counterpart which, at high frequencies, show flares with the same 16.6 day periodicity as the X-ray intensity. In each cycle the radio flare occurs shortly after the intensity drop-off which defines the X-ray modulation. The radio source is positionally coincident with a faint red star having very strong H..cap alpha.. and weak He I emission lines which are probably variable. The object may be an early-type emission-line star or a symbiotic star, at a distance of 10 kpc.

  6. Swift-XRT detects X-ray burst from Circinus X-1

    NARCIS (Netherlands)

    Linares, M.; Soleri, P.; Altamirano, D.; Armas-Padilla, M.; Cavecchi, Y.; Degenaar, N.; Kalamkar, M.; Kaur, R.; van der Klis, M.; Patruno, A.; Watts, A.; Wijnands, R.; Yang, Y.; Casella, P.; Rea, N.; Chakrabarty, D.; Homan, J.

    Following the recent re-brightening (ATel #2608) and RXTE-PCA detection of X-ray bursts from the peculiar X-ray binary Cir X-1 between May 15 and 25 (ATel #2643), we obtained a series of Swift-XRT observations of the field (see also ATel #2650). Swift-XRT detected an X-ray burst on 2010-05-28 at

  7. The mass of the black hole in the X-ray binary LMC X-1

    Science.gov (United States)

    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].

  8. New radio observations of the Circinus Galaxy

    International Nuclear Information System (INIS)

    Harnett, J.I.; Reynolds, J.E.

    1990-01-01

    We present new radio continuum and OH observations of the Circinus Galaxy which confirm the active nature of the nucleus. The continuum structure is dominated by two spurs of emission, which probably originate in the core and extend roughly along the minor axis of the galaxy. In addition, the OH absorption profiles clearly indicate a rapidly rotating cloud surrounding the nucleus or several independent clouds in the vicinity with inflowing and outflowing motions. The Circinus Galaxy is most probably a Seyfert with underlying nuclear starburst activity. (author)

  9. Detection of Reflection Features in the Neutron Star Low-mass X-Ray Binary Serpens X-1 with NICER

    Science.gov (United States)

    Ludlam, R. M.; Miller, J. M.; Arzoumanian, Z.; Bult, P. M.; Cackett, E. M.; Chakrabarty, D.; Enoto, T.; Fabian, A. C.; Gendreau, K. C.; Guillot, S.; Homan, J.; Jaisawal, G. K.; Keek, L.; La Marr, B.; Malacaria, C.; Markwardt, C. B.; Steiner, J. F.; Strohmayer, T. E.

    2018-05-01

    We present Neutron Star Interior Composition Explorer (NICER) observations of the neutron star (NS) low-mass X-ray binary Serpens X-1 during the early mission phase in 2017. With the high spectral sensitivity and low-energy X-ray passband of NICER, we are able to detect the Fe L line complex in addition to the signature broad, asymmetric Fe K line. We confirm the presence of these lines by comparing the NICER data to archival observations with XMM-Newton/Reflection Grating Spectrometer (RGS) and NuSTAR. Both features originate close to the innermost stable circular orbit (ISCO). When modeling the lines with the relativistic line model RELLINE, we find that the Fe L blend requires an inner disk radius of {1.4}-0.1+0.2 R ISCO and Fe K is at {1.03}-0.03+0.13 R ISCO (errors quoted at 90%). This corresponds to a position of {17.3}-1.2+2.5 km and {12.7}-0.4+1.6 km for a canonical NS mass ({M}NS}=1.4 {M}ȯ ) and dimensionless spin value of a = 0. Additionally, we employ a new version of the RELXILL model tailored for NSs and determine that these features arise from a dense disk and supersolar Fe abundance.

  10. Detection of Reflection Features in the Neutron Star Low-mass X-Ray Binary Serpens X-1 with NICER

    DEFF Research Database (Denmark)

    Ludlam, R. M.; Miller, J. M.; Arzoumanian, Z.

    2018-01-01

    We present Neutron Star Interior Composition Explorer (NICER) observations of the neutron star (NS) low-mass X-ray binary Serpens X-1 during the early mission phase in 2017. With the high spectral sensitivity and low-energy X-ray passband of NICER, we are able to detect the Fe L line complex in a...

  11. LMC X-1: A New Spectral Analysis of the O-star in the Binary and Surrounding Nebula

    Science.gov (United States)

    Hyde, E. A.; Russell, D. M.; Ritter, A.; Filipović, M. D.; Kaper, L.; Grieve, K.; O'Brien, A. N.

    2017-09-01

    We provide new observations of the LMC X-1 O star and its extended nebula structure using spectroscopic data from VLT/UVES as well as Hα imaging from the Wide Field Imager on the Max Planck Gesellschaft/European Southern Observatory 2.2 m telescope and ATCA imaging of the 2.1 GHz radio continuum. This nebula is one of the few known to be energized by an X-ray binary. We use a new spectrum extraction technique that is superior to other methods used to obtain both radial velocities and fluxes. This provides an updated spatial velocity of ≃ 21.0 +/- 4.8 km s-1 for the O star. The slit encompasses both the photo-ionized and shock-ionized regions of the nebula. The imaging shows a clear arc-like structure reminiscent of a wind bow shock in between the ionization cone and shock-ionized nebula. The observed structure can be fit well by the parabolic shape of a wind bow shock. If an interpretation of a wind bow shock system is valid, we investigate the N159-O1 star cluster as a potential parent of the system, suggesting a progenitor mass of ˜60 M ⊙ for the black hole. We further note that the radio emission could be non-thermal emission from the wind bow shock, or synchrotron emission associated with the jet-inflated nebula. For both wind- and jet-powered origins, this would represent one of the first radio detections of such a structure.

  12. An extremely luminous and variable ultraluminous X-ray source in the outskirts of Circinus observed with NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Walton, D. J.; Fuerst, F.; Harrison, F.; Stern, D.; Grefenstette, B. W.; Madsen, K. K.; Rana, V. [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Bachetti, M.; Barret, D.; Webb, N. A. [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Bauer, F. [Instituto de Astrofísica, Facultad de Física, Pontificia Universidad Católica de Chile, 306, Santiago 22 (Chile); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Miller, J. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Ptak, A.; Zhang, W. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-12-20

    Following a serendipitous detection with the Nuclear Spectroscopic Telescope Array (NuSTAR), we present a multi-epoch spectral and temporal analysis of an extreme ultraluminous X-ray source (ULX) located in the outskirts of the Circinus galaxy, hereafter Circinus ULX5, including coordinated XMM-Newton+NuSTAR follow-up observations. The NuSTAR data presented here represent one of the first instances of a ULX reliably detected at hard (E > 10 keV) X-rays. Circinus ULX5 is variable on long time scales by at least a factor of ∼5 in flux, and was caught in a historically bright state during our 2013 observations (0.3-30.0 keV luminosity of 1.6 × 10{sup 40} erg s{sup –1}). During this epoch, the source displayed a curved 3-10 keV spectrum, broadly similar to other bright ULXs. Although pure thermal models result in a high energy excess in the NuSTAR data, this excess is too weak to be modeled with the disk reflection interpretation previously proposed to explain the 3-10 keV curvature in other ULXs. In addition to flux variability, clear spectral variability is also observed. While in many cases the interpretation of spectral components in ULXs is uncertain, the spectral and temporal properties of all the high quality data sets currently available strongly support a simple disk-corona model reminiscent of that invoked for Galactic binaries, with the accretion disk becoming more prominent as the luminosity increases. However, although the disk temperature and luminosity are well correlated across all time scales currently probed, the observed luminosity follows L∝T {sup 1.70±0.17}, flatter than expected for simple blackbody radiation. The spectral variability displayed here is highly reminiscent of that observed from known Galactic black hole binaries (BHBs) at high luminosities. This comparison implies a black hole mass of ∼90 M {sub ☉} for Circinus ULX5. However, given the diverse behavior observed from Galactic BHB accretion disks, this mass estimate is

  13. Thermodynamic study of binary mixture of x1[C6mim][BF4] + x21-propanol: Measurements and molecular modeling

    International Nuclear Information System (INIS)

    Kermanpour, F.; Sharifi, T.

    2012-01-01

    Highlights: ► Densities and viscosities for binary mixture of {x 1 [C 6 mim][BF 4 ] + x 2 1-propanol} were measured at different temperatures. ► The excess molar functions were calculated from the obtained experimental data. ► These data were correlated with the Redlich–Kister equation and PFP model to obtain the coefficients and standard deviations. - Abstract: Densities, ρ, and viscosities, η, of pure 1-hexyl-3-methylimidazoliumtetrafluoro borate ([C 6 mim][BF 4 ]) and 1-propanol, and their binary mixture {x 1 [C 6 mim][BF 4 ] + x 2 1-propanol} were measured at atmospheric pressure and in the temperature range of 293.15–333.15 K. The excess molar volumes, V m E , thermal expansion coefficients, α, and their excess values, α E , isothermal coefficient of excess molar enthalpy, (∂H m E /∂p) T,x and excess viscosities, η E , were calculated from the experimental values of densities and viscosities. The excess molar volumes of the binary mixture are negative over the entire mole fraction range and increase with increasing temperature. Excess viscosities are negative over the entire mole fraction range of the mixture and decrease with increasing temperature. The obtained excess molar volumes and excess viscosities were correlated with the Redlich–Kister equation. The experimental results have also been used to examine the applicability of Prigogine–Flory–Patterson (PFP) theory in predicting the excess molar volume of the binary mixture. It is indicated that agreement between excess molar volumes calculated via PFP theory and the experimental results is good in all temperatures.

  14. On the Nature of the Variability Power Decay towards Soft Spectral States in X-Ray Binaries. Case Study in Cyg X-1

    Science.gov (United States)

    Titarchuk, Lev; Shaposhinikov, Nikolai

    2007-01-01

    A characteristic feature of the Fourier Power Density Spectrum (PDS) observed from black hole X-ray binaries in low/hard and intermediate spectral states is a broad band-limited noise, characterized by a constant below some frequency (a "break" frequency) and a power law above this frequency. It has been shown that the variability of this type can be produced by the inward diffusion of the local driving perturbations in a bounded configuration (accretion disk or corona). In the framework of this model, the perturbation diffusion time to is related to the phenomenological break frequency, while the PDS power-law slope above the "break" is determined by the viscosity distribution over the configuration. The perturbation diffusion scenario explains the decay of the power of X-ray variability observed in a number of compact sources (containing black hole and neutron star) during an evolution of theses sources from low/hard to high/soft states. We compare the model predictions with the subset of data from Cyg X-1 collected by the Rossi X-ray Time Explorer (RXTE). Our extensive analysis of the Cyg X-1 PDSs demonstrates that the observed integrated power P(sub x), decreases approximately as a square root of the characteristic frequency of the driving oscillations v(sub dr). The RXTE observations of Cyg X-1 allow us to infer P(sub dr), and t(sub o) as a function of v(sub dr). We also apply the basic parameters of observed PDSs, power-law index and low frequency quasiperiodic oscillations. to infer Reynolds (Re) number from the observations using the method developed in our previous paper. Our analysis shows that Re-number increases from values about 10 in low/hard state to that about 70 during the high/soft state. Subject headings: accretion, accretion disks-black hole physics-stars:individual (Cyg X-1) :radiation mechanisms: nonthermal-physical data and processes

  15. Measurement of the masses of the neutron star, Her X-1, and its binary companion, HZ Her, as derived from the study of 1.24-second optical pulsations from the Hz Her - Her X-1 binary system and the x ray-to-optical reprocessing reflection and transmission mechanisms

    International Nuclear Information System (INIS)

    Middleditch, J.

    1975-10-01

    Intermittent optical pulsations at the 0.1--0.3 percent level have been detected from this binary system in over 500 hours of optical observations. These pulsations are present only for well defined values of the 1.7-day (binary) and 35-day phases. Positions of the pulsation-emitting regions, projected onto the orbital plane, have been measured and three distinct regions have been resolved. A simple model is put forth which accounts for the observed binary behavior, which gives a direct determination of the mass ratio, M/sub HZ Her//M/sub Her X-1/ = 1.69 +- 0.05, and which establishes that the spin of the pulsar is prograde. Additionally it is shown that HZ Her fills its critical Roche lobe. Using the above, the known x ray eclipse duration, and the mass function, the orbital inclination is calculated to be i = 85 0 +- 5 0 and the masses to be M/sub Her X-1/ = 1.28 +- 0.08 M/sub solar/ and M/sub HZ Her/ = 2.16 +- 0.07 M/sub solar/. Constraints on the physical parameters of the accretion stream and disk are derived from the data. The nature of the 35-day modulation of the data is discussed in relation to various models

  16. On the Evolution of the Inner Disk Radius with Flux in the Neutron Star Low-mass X-Ray Binary Serpens X-1

    Science.gov (United States)

    Chiang, Chia - Ying; Morgan, Robert A.; Cackett, Edward M.; Miller, Jon M.; Bhattacharyya, Sudip; Strohmayer, Tod E.

    2016-01-01

    We analyze the latest Suzaku observation of the bright neutron star (NS) low-mass X-ray binary Serpens X-1 taken in 2013 October and 2014 April. The observation was taken using the burst mode and only suffered mild pile-up effects. A broad iron line is clearly detected in the X-ray spectrum. We test different models and find that the iron line is asymmetric and best interpreted by relativistic reflection. The relativistically broadened iron line is generally believed to originate from the innermost regions of the accretion disk, where strong gravity causes a series of special and general relativistic effects. The iron line profile indicates an inner radius of approx. 8 R(sub G), which gives an upper limit on the size of the NS. The asymmetric iron line has been observed in a number of previous observations, which gives several inner radius measurements at different flux states. We find that the inner radius of Serpens X-1 does not evolve significantly over the range of L/L(sub Edd) approx. 0.4-0.6, and the lack of flux dependence of the inner radius implies that the accretion disk may be truncated outside of the innermost stable circular orbit by the boundary layer, rather than the stellar magnetic field.

  17. ON THE EVOLUTION OF THE INNER DISK RADIUS WITH FLUX IN THE NEUTRON STAR LOW-MASS X-RAY BINARY SERPENS X-1

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Chia-Ying; Morgan, Robert A.; Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock, Detroit, MI 48202 (United States); Miller, Jon M. [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1046 (United States); Bhattacharyya, Sudip [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Strohmayer, Tod E., E-mail: ft8320@wayne.edu [X-Ray Astrophysics Lab, Astrophysics Science Division, NASA’s Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-11-01

    We analyze the latest Suzaku observation of the bright neutron star (NS) low-mass X-ray binary Serpens X-1 taken in 2013 October and 2014 April. The observation was taken using the burst mode and only suffered mild pile-up effects. A broad iron line is clearly detected in the X-ray spectrum. We test different models and find that the iron line is asymmetric and best interpreted by relativistic reflection. The relativistically broadened iron line is generally believed to originate from the innermost regions of the accretion disk, where strong gravity causes a series of special and general relativistic effects. The iron line profile indicates an inner radius of ∼8 R {sub G}, which gives an upper limit on the size of the NS. The asymmetric iron line has been observed in a number of previous observations, which gives several inner radius measurements at different flux states. We find that the inner radius of Serpens X-1 does not evolve significantly over the range of L / L {sub Edd} ∼ 0.4–0.6, and the lack of flux dependence of the inner radius implies that the accretion disk may be truncated outside of the innermost stable circular orbit by the boundary layer, rather than the stellar magnetic field.

  18. A TEST OF THE NATURE OF THE FE K LINE IN THE NEUTRON STAR LOW-MASS X-RAY BINARY SERPENS X-1

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Chia-Ying; Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock, Detroit, MI 48202 (United States); Miller, Jon M. [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI48109-1046 (United States); Barret, Didier [Universite de Toulouse, UPS-OMP, Toulouse (France); Fabian, Andy C.; Parker, Michael L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); D’Aì, Antonino [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo, via U. La Malfa 153, I-90146 Palermo (Italy); Bhattacharyya, Sudip [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Burderi, Luciano [Dipartimento di Fisica, Università degli Studi di Cagliari, SP Monserrato-Sestu, KM 0.7, I-09042 Monserrato (Italy); Salvo, Tiziana Di; Iaria, Rosario [Dipartimento di Fisica e Chimica, Universitá di Palermo, via Archirafi 36, I-90123 Palermo (Italy); Egron, Elise [INAF-Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy); Homan, Jeroen [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue 37-582D, Cambridge, MA 02139 (United States); Lin, Dacheng [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States); Miller, M. Coleman, E-mail: ft8320@wayne.edu [Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742-2421 (United States)

    2016-04-20

    Broad Fe K emission lines have been widely observed in the X-ray spectra of black hole systems as well as in neutron star systems. The intrinsically narrow Fe K fluorescent line is generally believed to be part of the reflection spectrum originating in an illuminated accretion disk which is broadened by strong relativistic effects. However, the nature of the lines in neutron star low-mass X-ray binaries (LMXBs) has been a matter of debate. We therefore obtained the longest, high-resolution X-ray spectrum of a neutron star LMXB to date with a 300 ks Chandra High Energy Transmission Grating Spectrometer (HETGS) observation of Serpens X-1. The observation was taken under the “continuous clocking” mode, and thus was free of photon pile-up effects. We carry out a systematic analysis and find that the blurred reflection model fits the Fe line of Serpens X-1 significantly better than a broad Gaussian component does, implying that the relativistic reflection scenario is much preferred. Chandra HETGS also provides a highest spectral resolution view of the Fe K region and we find no strong evidence for additional narrow lines.

  19. 3D Doppler Tomography of the X-Ray Binary System Cygnus X-1 from Spectral Observations in 2007 in the HeII λ 4686 Å Line

    Science.gov (United States)

    Agafonov, M. I.; Karitskaya, E. A.; Sharova, O. I.; Bochkarev, N. G.; Zharikov, S. V.; Butenko, G. Z.; Bondar', A. V.; Sidorov, M. Yu.

    2018-02-01

    The results of a 3D Doppler tomography analysis for the X-ray binary system Cyg X-1 in the HeII λ 4686 Å line are presented. Information about the motions of gaseous flows outside the orbital plane has been obtained for the first time. Line profiles obtained in June 2007 on the 2-m telescope of the Terskol Branch of the Institute of Astronomy (Russia) and on the 2.1-m telescope of the National Astronomical Observatory of Mexico were used. A detailed analysis of these spectral data is presented: the distribution of the data in time, distribution of orbital phases for the projections, comparison of the line profile shapes for the data from two observatories. The geometry of the total transfer function obtained in the reconstruction is considered. The possibility of applying the profiles obtained to realize 3D tomography is justified. The resolution of the constructed 3D tomogram in velocity space is 60 × 60 × 40 km/s for V x , V y , V z . Fifteen cross sections for 15 different V z values perpendicular to the orbital plane are presented. The intensity distributions corresponding to the velocities of gaseous structures in the binary system are obtained. The reconstruction was realized using the radio-astronomical approach, developed for solving problems in tomography with a limited number of projections.

  20. SPECTRAL-TIMING ANALYSIS OF THE LOWER kHz QPO IN THE LOW-MASS X-RAY BINARY AQUILA X-1

    Energy Technology Data Exchange (ETDEWEB)

    Troyer, Jon S.; Cackett, Edward M., E-mail: jon.troyer@wayne.edu [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock St, Detroit, MI 48201 (United States)

    2017-01-10

    Spectral-timing products of kilohertz quasi-periodic oscillations (kHz QPOs) in low-mass X-ray binary (LMXB) systems, including energy- and frequency-dependent lags, have been analyzed previously in 4U 1608-52, 4U 1636-53, and 4U 1728-34. Here, we study the spectral-timing properties of the lower kHz QPO of the neutron star LMXB Aquila X-1 for the first time. We compute broadband energy lags as well as energy-dependent lags and the covariance spectrum using data from the Rossi X-ray Timing Explorer . We find characteristics similar to those of previously studied systems, including soft lags of ∼30 μ s between the 3.0–8.0 keV and 8.0–20.0 keV energy bands at the average QPO frequency. We also find lags that show a nearly monotonic trend with energy, with the highest-energy photons arriving first. The covariance spectrum of the lower kHz QPO is well fit by a thermal Comptonization model, though we find a seed photon temperature higher than that of the mean spectrum, which was also seen in Peille et al. and indicates the possibility of a composite boundary layer emitting region. Lastly, we see in one set of observations an Fe K component in the covariance spectrum at 2.4- σ confidence, which may raise questions about the role of reverberation in the production of lags.

  1. THE MOLECULAR WIND IN THE NEAREST SEYFERT GALAXY CIRCINUS REVEALED BY ALMA

    Energy Technology Data Exchange (ETDEWEB)

    Zschaechner, Laura K.; Walter, Fabian; Farina, Emanuele P.; Kruijssen, J. M. Diederik [Max Planck Institute für Astronomie—Königstuhl 17, D-69117 Heidelberg (Germany); Bolatto, Alberto; Veilleux, Sylvain [Department of Astronomy and Joint Space Science Institute, University of Maryland, College Park, MD 20642 (United States); Leroy, Adam [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Meier, David S. [Department of Physics, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 (United States); Ott, Jürgen, E-mail: zschaechner@mpia.de [National Radio Astronomy Observatory—P.O. Box O, 1003 Lopezville Road, Socorro, NM 87801 (United States)

    2016-12-01

    We present ALMA observations of the inner 1′ (1.2 kpc) of the Circinus galaxy, the nearest Seyfert. We target CO (1–0) in the region associated with a well-known multiphase outflow driven by the central active galactic nucleus (AGN). While the geometry of Circinus and its outflow make disentangling the latter difficult, we see indications of outflowing molecular gas at velocities consistent with the ionized outflow. We constrain the mass of the outflowing molecular gas to be 1.5 × 10{sup 5}−5.1 × 10{sup 6} M {sub ⊙}, yielding a molecular outflow rate of 0.35–12.3 M {sub ⊙} yr{sup −1}. The values within this range are comparable to the star formation (SF) rate in Circinus, indicating that the outflow indeed regulates SF to some degree. The molecular outflow in Circinus is considerably lower in mass and energetics than previously studied AGN-driven outflows, especially given its high ratio of AGN luminosity to bolometric luminosity. The molecular outflow in Circinus is, however, consistent with some trends put forth by Cicone et al., including a linear relation between kinetic power and AGN luminosity, as well as its momentum rate versus bolometric luminosity (although the latter places Circinus among the starburst galaxies in that sample). We detect additional molecular species including CN and C{sup 17}O.

  2. An extremely luminous and variable ultraluminous x-ray source in the outskirts of circinus observed with NuSTAR

    DEFF Research Database (Denmark)

    Walton, D. J.; Fuerst, F.; Harrison, F.

    2013-01-01

    Following a serendipitous detection with the Nuclear Spectroscopic Telescope Array (NuSTAR), we present a multi-epoch spectral and temporal analysis of an extreme ultraluminous X-ray source (ULX) located in the outskirts of the Circinus galaxy, hereafter Circinus ULX5, including coordinated XMM-N...

  3. The spectral and temporal behavior of the variable X-ray binary star Cyg X-1 in the hard region of X-radiation

    International Nuclear Information System (INIS)

    Steinle, H.

    1981-01-01

    In the present work the measurements of the X-ray spectrum of Cyg X-1 in the energy range 15 to 160 keV in the years 1975, 1976, 1977 are investigated. The measurements are of such a good quality, that a simple power spectrum as the best fit of a model to the data of Cyg X-1 can be excluded because the spectrum breaks off in the range 70-100 keV. The model of Sunyaev and Titarchuk which describes the comptonizing of protons will low energy in a hot plasma is used first time for filling to the Cyg X-1 spectra and it is seen, that the shape of the spectrum is represented in an excellent manner. From the parameters of the best fit to the spectrum from 1977 an electron temperature of 3.4 x 10 8 K and an optical depth tau = 5 for the plasma in which the photons are scattered are found. (orig./WB) [de

  4. Balloon observation of the binary X-ray source Her X-1 1.24 sec pulsation and cyclotron line emission

    International Nuclear Information System (INIS)

    Pietsch, W.; Reppin, C.; Truemper, J.; Voges, W.; Kendziorra, E.; Staubert, R.; Tuebingen Univ.

    1978-01-01

    During a balloon observation from Palestine, Texas, the authors detected for the first time the 1.24 sec pulsation of Hercules X-1 in the hard X-ray range up to 70 keV and discovered strong line emission in its spectrum at 58 keV. They estimated a line flux of 3x10 -3 photons cm -2 sec -1 and a line width of less than 12 keV. The phenomenon is interpreted as electron cyclotron emission at the basic frequency emitted by the hot polar plasma of the rotating neutron star. The line measured leads to a magnetic field strength of 5.3x10 12 gauss. In further observations during a balloon campaign in Sept./Oct. 1977 the authors confirmed the existence of the line emission and for the first time found pulsed X-ray emission above 15 keV during the 'short on' - and 'off'-state of the Her X-1 35 day cycle. The pulse to interpulse ratio seems to vary with the 35 day phase

  5. SUBMILLIMETER H{sub 2}O MEGAMASERS IN NGC 4945 AND THE CIRCINUS GALAXY

    Energy Technology Data Exchange (ETDEWEB)

    Pesce, D. W. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Braatz, J. A.; Impellizzeri, C. M. V., E-mail: dpesce@virginia.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2016-08-10

    We present 321 GHz observations of five active galactic nuclei (AGNs) from ALMA Cycle 0 archival data: NGC 5793, NGC 1068, NGC 1386, NGC 4945, and the Circinus galaxy. Submillimeter maser emission is detected for the first time toward NGC 4945, and we present a new analysis of the submillimeter maser system in Circinus. None of the other three galaxies show maser emission, although we have detected and imaged the continuum from every galaxy. Both NGC 4945 and Circinus are known to host strong (≳10 Jy) 22 GHz megamaser emission, and VLBI observations have shown that the masers reside in the innermost ∼1 pc of the galaxies. The peak flux densities of the 321 GHz masers in both systems are substantially weaker (by a factor of ∼100) than what is observed at 22 GHz, although the corresponding isotropic luminosities are more closely matched (within a factor of ∼10) between the two transitions. We compare the submillimeter spectra presented here to the known 22 GHz spectra in both galaxies, and we argue that while both transitions originate from the gaseous environment near the AGNs, not all sites are in common. In Circinus, the spectral structure of the 321 GHz masers indicates that they may trace the accretion disk at radii interior to the 22 GHz masers. The continuum emission in NGC 4945 and NGC 5793 shows a spatial distribution indicative of an origin in the galactic disks (likely thermal dust emission), while for the other three galaxies the emission is centrally concentrated and likely originates from the nucleus.

  6. Analysis of 3D Doppler Tomography of the X-ray Binary System Cygnus X-1 from Spectral Observations in 2007 in the HeII λ 4686 Å Line

    Science.gov (United States)

    Agafonov, M. I.; Karitskaya, E. A.; Sharova, O. I.; Bochkarev, N. G.; Zharikov, S. V.; Butenko, G. Z.; Bondar', A. V.; Bubukin, I. T.

    2018-03-01

    This is the second paper in a series dedicated to studies of the X-ray binary Cyg X-1 in the HeII λ 4686 Å line using 3D Doppler tomography. A detailed analysis of the tomogram constructed has made it possible for the first time to obtain information about the motions of gaseous flows including all three velocity components. The observations were obtained in June 2007 at the Terskol Branch of the Institute of Astronomy (Russia) and the National Astronomical Observatory of Mexico. The correctness of the tomographic results and their discussion is analyzed. The results are compared with a 2D Doppler tomogram reconstruction. Model-atmosphere computations of HeII λ 4686 Å line profiles are used to estimate the influence of absorption features of the Osupergiant on the emission structure in the tomogram. The correctness of the 3D solutions is confirmed by the good agreement between the original sequence of spectral data and a control data set computed using the constructed 3D Doppler tomogram. Tomograms constructed using the data of each of the two observatories are compared. The results of the reconstruction for inclinations of the system of 40° and 45° essentially coincide. The maximum absorption (corresponding to the O supergiant) and emission structural features in the 3D tomogram are located in its central ( V x , V y ) section, where the velocity component perpendicular to the orbital plane V z is zero. The emission is generated mainly in the outer part of the accretion structure, close to the supergiant. A gaseous stream from the Lagrangian point L1 with its motion close to the orbital plane can be distinguished. Its maximum velocity reaches 800 km/s. The identification of an emission structure with V z 300 km/s and with V x , V y in the velocity interval corresponding to the donor star was unexpected. Its presence may indicate, for example, an outflow of matter from a magnetic pole of the supergiant.

  7. THE ROTATION PERIOD OF HD-77581 (VELA X-1)

    NARCIS (Netherlands)

    ZUIDERWIJK, EJ

    The rotation period of HD 77581, supergiant primary in the X-ray binary Vela X-1, is determined from an analysis of selected absorption line profiles. The rotation rate determined from He I line profiles is 0.67 +/- 0.04 times that of the binary angular velocity, corresponding to a rotation velocity

  8. Modelling interstellar structures around Vela X-1

    Science.gov (United States)

    Gvaramadze, V. V.; Alexashov, D. B.; Katushkina, O. A.; Kniazev, A. Y.

    2018-03-01

    We report the discovery of filamentary structures stretched behind the bow-shock-producing high-mass X-ray binary Vela X-1 using the SuperCOSMOS H-alpha Survey and present the results of optical spectroscopy of the bow shock carried out with the Southern African Large Telescope. The geometry of the detected structures suggests that Vela X-1 has encountered a wedge-like layer of enhanced density on its way and that the shocked material of the layer partially outlines a wake downstream of Vela X-1. To substantiate this suggestion, we carried out 3D magnetohydrodynamic simulations of interaction between Vela X-1 and the layer for three limiting cases. Namely, we run simulations in which (i) the stellar wind and the interstellar medium (ISM) were treated as pure hydrodynamic flows, (ii) a homogeneous magnetic field was added to the ISM, while the stellar wind was assumed to be unmagnetized, and (iii) the stellar wind was assumed to possess a helical magnetic field, while there was no magnetic field in the ISM. We found that although the first two simulations can provide a rough agreement with the observations, only the third one allowed us to reproduce not only the wake behind Vela X-1, but also the general geometry of the bow shock ahead of it.

  9. A status report on Cygnus X-1

    International Nuclear Information System (INIS)

    Eardley, D.M.; Lightman, A.P.; Shakura, N.I.; Shapiro, S.L.; Sunyaev, R.A.

    1978-01-01

    Detailed models of gas flow and X-ray production are discussed, but it is concluded that the strongest argument in favour of a black hole is that Cygnus X-1 is a compact object, and has a mass larger than that allowed for a neutron star or white dwarf. Evidence for the former feature is associated with the observation of very rapid time variability in X-rays. Evidence for the latter follows from a union of various types of observations of the Cyg X-1 star system, in which the visible star is the single-line spectroscopic binary HDE 226868, a normal supergiant. The evidence is reviewed under the following headings: geometry of the accretion flow; emission mechanism; time variability. (U.K.)

  10. First Near-infrared Imaging Polarimetry of Young Stellar Objects in the Circinus Molecular Cloud

    Science.gov (United States)

    Kwon, Jungmi; Nakagawa, Takao; Tamura, Motohide; Hough, James H.; Choi, Minho; Kandori, Ryo; Nagata, Tetsuya; Kang, Miju

    2018-02-01

    We present the results of near-infrared (NIR) linear imaging polarimetry in the J, H, and K s bands of the low-mass star cluster-forming region in the Circinus Molecular Cloud Complex. Using aperture polarimetry of point-like sources, positive detection of 314, 421, and 164 sources in the J, H, and K s bands, respectively, was determined from among 749 sources whose photometric magnitudes were measured. For the source classification of the 133 point-like sources whose polarization could be measured in all 3 bands, a color–color diagram was used. While most of the NIR polarizations of point-like sources are well-aligned and can be explained by dichroic polarization produced by aligned interstellar dust grains in the cloud, 123 highly polarized sources have also been identified with some criteria. The projected direction on the sky of the magnetic field in the Cir-MMS region is indicated by the mean polarization position angles (70°) of the point-like sources in the observed region, corresponding to approximately 1.6× 1.6 pc2. In addition, the magnetic field direction is compared with the outflow orientations associated with Infrared Astronomy Satellite sources, in which two sources were found to be aligned with each other and one source was not. We also show prominent polarization nebulosities over the Cir-MMS region for the first time. Our polarization data have revealed one clear infrared reflection nebula (IRN) and several candidate IRNe in the Cir-MMS field. In addition, the illuminating sources of the IRNe are identified with near- and mid-infrared sources.

  11. X-1E on Lakebed

    Science.gov (United States)

    1955-01-01

    The Bell Aircraft Corporation X-1E in 1955 on the Rogers Dry Lakebed near the NACA High-Speed Flight Station, Edwards, California. The X-1E was notable for being shorter, with a thinner wing than the X-1A, -B, and -D. Aerodynamic heating caused the ailerons, rudder, and elevators to remain unpainted throughout the X-1E's flight test program. When the ventral fins were added, they were left unpainted too. On August 31, 1956, the aircraft reached a top speed of 1,480 miles per hour (Mach 2.24). There were four versions of the Bell X-1 rocket-powered research aircraft that flew at the NACA High-Speed Flight Research Station, Edwards, California. The bullet-shaped X-1 aircraft were built by Bell Aircraft Corporation, Buffalo, N.Y. for the U.S. Army Air Forces (after 1947, U.S. Air Force) and the National Advisory Committee for Aeronautics (NACA). The X-1 Program was originally designated the XS-1 for EXperimental Supersonic. The X-1's mission was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the 'sound barrier.' Three different X-1s were built and designated: X-1-1, X-1-2 (later modified to become the X-1E), and X-1-3. The basic X-1 aircraft were flown by a large number of different pilots from 1946 to 1951. The X-1 Program not only proved that humans could go beyond the speed of sound, it reinforced the understanding that technological barriers could be overcome. The X-1s pioneered many structural and aerodynamic advances including extremely thin, yet extremely strong wing sections; supersonic fuselage configurations; control system requirements; powerplant compatibility; and cockpit environments. The X-1 aircraft were the first transonic-capable aircraft to use an all-moving stabilizer. The flights of the X-1s opened up a new era in aviation. The first X-1 was air-launched unpowered from a Boeing B-29 Superfortress on January 25, 1946. Powered flights began in December 1946. On October 14

  12. Long-term studies with the Ariel 5 ASM. I - Hercules X-1, Vela X-1, and Centaurus X-3

    Science.gov (United States)

    Holt, S. S.; Kaluzienski, L. J.; Boldt, E. A.; Serlemitsos, P. A.

    1979-01-01

    Twelve hundred days of 3-6 keV X-ray data from Her X-1, Vela X-1, and Cen X-3 accumulated with the Ariel 5 All-Sky Monitor are interrogated. The binary periodicities of all three can be clearly observed, as can the 35 day variation of Her X-1, for which we can refine the period to 34.875 plus or minus 0.030 days. No such longer-term periodicity less than 200 days is observed from Vela X-1. The 26.6 days low-state recurrence period for Cen X-3 is not observed, but a 43.0 day candidate periodicity is found which may be consistent with the precession of an accretion disk in that system. The present results are illustrative of the long-term studies which can be performed on approximately 50 sources over a temporal base which will ultimately extend to at least 1800 days.

  13. Circumnuclear Multi-phase Gas in the Circinus Galaxy. I. Non-LTE Calculations of CO Lines

    Science.gov (United States)

    Wada, Keiichi; Fukushige, Ryosuke; Izumi, Takuma; Tomisaka, Kohji

    2018-01-01

    In this study, we investigate the line emissions from cold molecular gas based on our previous “radiation-driven fountain model,” which reliably explains the spectral energy distribution of the nearest type 2 Seyfert galaxy, the Circinus galaxy. Using a snapshot of the best-fit radiation-hydrodynamic model for the central r≤slant 16 pc, in which non-equilibrium X-ray-dominated region chemistry is solved, we conduct post-processed non-local thermodynamic equilibrium radiation transfer simulations for the CO lines. We obtain a spectral line energy distribution with a peak around J≃ 6, and its distribution suggests that the lines are not thermalized. However, for a given line of sight, the optical depth distribution is highly non-uniform between {τ }ν \\ll 1 and {τ }ν \\gg 1. The CO-to-H2 conversion factor ({X}{CO}), which can be directly obtained from the results and is not a constant, depends strongly on the integrated intensity and differs from the fiducial value for local objects. {X}{CO} exhibits a large dispersion of more than one order of magnitude, reflecting the non-uniform internal structure of a “torus.” In addition, we found that the physical conditions differ between grid cells on a scale of a few parsecs along the observed lines of sight; therefore, a specific observed line ratio does not necessarily represent a single physical state of the interstellar medium.

  14. Interacting binaries

    International Nuclear Information System (INIS)

    Eggleton, P.P.; Pringle, J.E.

    1985-01-01

    This volume contains 15 review articles in the field of binary stars. The subjects reviewed span considerably, from the shortest period of interacting binaries to the longest, symbiotic stars. Also included are articles on Algols, X-ray binaries and Wolf-Rayet stars (single and binary). Contents: Preface. List of Participants. Activity of Contact Binary Systems. Wolf-Rayet Stars and Binarity. Symbiotic Stars. Massive X-ray Binaries. Stars that go Hump in the Night: The SU UMa Stars. Interacting Binaries - Summing Up

  15. Scorpius X-1 - an evolving double radio source

    International Nuclear Information System (INIS)

    Geldzahler, B.J.; Fomalont, E.B.; National Radio Astronomy Observatory, Charlottesville, VA)

    1986-01-01

    The radio emission from Sco X-1 has been monitored with the VLA over a 5 yr period with 0.4 arcsec resolution at 4.85 GHz. The source contains three components: an unresolved radio core coincident with the stellar binary system; an unresolved lobe northeast of the core; and an extended lobe southwest of the core. All radio components are approximately comoving with the binary system and are thus undoubtedly associated with it. The northeast lobe is moving away from the core at a rate of 0.013-0.017 arcsec/yr, which corresponds to a velocity of 31-41 km/sec, assuming a distance of 500 pc to Sco X-1. The relative velocity of a hot spot in the southwest lobe with respect to the core is less than 70 km/sec. The flux density in the lobes appears to vary by about 20 percent over time scales of 1 yr, and the variations between the lobes may be correlated. The twin-exhaust beam model where energy is transported from the core to the lobes in narrow beams is the most acceptable model for the evolution of the source. However, interstellar density (greater than 0.6/cu cm) is needed to restrain the velocity of the northeast lobe (presumably the working surface of the beam). 16 references

  16. Optical studies of massive X-ray binaries

    International Nuclear Information System (INIS)

    Zuiderwijk, E.J.

    1979-01-01

    Photometric and spectroscopic studies of several optical counterparts of massive X-ray binaries are presented. Subjects of study were the binary systems:HD77581/4U0900-40 (Vela X-1), HD153919/4U1700-37, Wray 977/4U1223-62 and Sk160/4U0115-74 (=SMC X-1). (Auth.)

  17. Subluminous X-ray binaries

    NARCIS (Netherlands)

    Armas Padilla, M.

    2013-01-01

    The discovery of the first X-ray binary, Scorpius X-1, by Giacconi et al. (1962), marked the birth of X-ray astronomy. Following that discovery, many additional X-ray sources where found with the first generation of X-ray rockets and observatories (e.g., UHURU and Einstein). The short-timescale

  18. A NICER Look at the Aql X-1 Hard State

    Science.gov (United States)

    Bult, Peter; Arzoumanian, Zaven; Cackett, Edward M.; Chakrabarty, Deepto; Gendreau, Keith C.; Guillot, Sebastien; Homan, Jeroen; Jaisawal, Gaurava K.; Keek, Laurens; Kenyon, Steve; Lamb, Frederick K.; Ludlam, Renee; Mahmoodifar, Simin; Markwardt, Craig; Miller, Jon M.; Prigozhin, Gregory; Soong, Yang; Strohmayer, Tod E.; Uttley, Phil

    2018-05-01

    We report on a spectral-timing analysis of the neutron star low-mass X-ray binary (LMXB) Aql X-1 with the Neutron Star Interior Composition Explorer (NICER) on the International Space Station (ISS). Aql X-1 was observed with NICER during a dim outburst in 2017 July, collecting approximately 50 ks of good exposure. The spectral and timing properties of the source correspond to that of a (hard) extreme island state in the atoll classification. We find that the fractional amplitude of the low-frequency (soft thermal emission and the power-law emission. Additionally, we measure hard time lags, indicating the thermal emission at 0.5 keV leads the power-law emission at 10 keV on a timescale of ∼100 ms at 0.3 Hz to ∼10 ms at 3 Hz. Our results demonstrate that the thermal emission in the hard state is intrinsically variable, and is driving the modulation of the higher energy power-law. Interpreting the thermal spectrum as disk emission, we find that our results are consistent with the disk propagation model proposed for accretion onto black holes.

  19. Cray X1 Evaluation Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, J.S.

    2004-02-09

    On August 15, 2002 the Department of Energy (DOE) selected the Center for Computational Sciences (CCS) at Oak Ridge National Laboratory (ORNL) to deploy a new scalable vector supercomputer architecture for solving important scientific problems in climate, fusion, biology, nanoscale materials and astrophysics. ''This program is one of the first steps in an initiative designed to provide U.S. scientists with the computational power that is essential to 21st century scientific leadership,'' said Dr. Raymond L. Orbach, director of the department's Office of Science The Cray X1 is an attempt to incorporate the best aspects of previous Cray vector systems and massively-parallel-processing (MPP) systems into one design. Like the Cray T90, the X1 has high memory bandwidth, which is key to realizing a high percentage of theoretical peak performance. Like the Cray T3E, the X1 has a high-bandwidth, low-latency, scalable interconnect, and scalable system software. And, like the Cray SV1, the X1 leverages commodity off-the-shelf (CMOS) technology and incorporates non-traditional vector concepts, like vector caches and multi-streaming processors. In FY03, CCS procured a 256-processor Cray X1 to evaluate the processors, memory subsystem, scalability of the architecture, software environment and to predict the expected sustained performance on key DOE applications codes. The results of the micro-benchmarks and kernel benchmarks show the architecture of the Cray X1 to be exceptionally fast for most operations. The best results are shown on large problems, where it is not possible to fit the entire problem into the cache of the processors. These large problems are exactly the types of problems that are important for the DOE and ultra-scale simulation.

  20. Atmospheric chemistry of n-CxF2x+1CHO (x = 1, 2, 3, 4)

    DEFF Research Database (Denmark)

    Hurley, M. D.; Ball, J. C.; Wallington, T. J.

    2006-01-01

    Smog chamber/FTIR techniques were used to study the atmospheric fate of n-C(x)F(2)(x)(+1)C(O) (x = 1, 2, 3, 4) radicals in 700 Torr O(2)/N(2) diluent at 298 +/- 3 K. A competition is observed between reaction with O(2) to form n-C(x)()F(2)(x)()(+1)C(O)O(2) radicals and decomposition to form n-C(x...... to the atmospheric chemistry of n-C(x)F(2)(x)(+1)C(O) radicals and their possible role in contributing to the formation of perfluorocarboxylic acids in the environment....

  1. SUPERORBITAL PHASE-RESOLVED ANALYSIS OF SMC X-1

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chin-Ping; Chou, Yi; Yang, Ting-Chang; Su, Yi-Hao, E-mail: m929011@astro.ncu.edu.tw, E-mail: yichou@astro.ncu.edu.tw [Graduate Institute of Astronomy, National Central University, Jhongli 32001, Taiwan (China)

    2013-08-10

    The high-mass X-ray binary SMC X-1 is an eclipsing binary with an orbital period of 3.89 days. This system exhibits a superorbital modulation with a period varying between {approx}40 days and {approx}65 days. The instantaneous frequency and the corresponding phase of the superorbital modulation can be obtained by a recently developed time-frequency analysis technique, the Hilbert-Huang transform (HHT). We present a phase-resolved analysis of both the spectra and the orbital profiles with the superorbital phase derived from the HHT. The X-ray spectra observed by the Proportional Counter Array on board the Rossi X-ray Timing Explorer are fitted well by a blackbody plus a Comptonized component. The plasma optical depth, which is a good indicator of the distribution of material along the line of sight, is significantly anti-correlated with the flux detected at 2.5-25 keV. However, the relationship between the plasma optical depth and the equivalent width of the iron line is not monotonic. There is no significant correlation for fluxes higher than {approx}35 mCrab but clear positive correlation when the intensity is lower than {approx}20 mCrab. This indicates that the iron line production is dominated by different regions of this binary system in different superorbital phases. To study the dependence of the orbital profile on the superorbital phase, we obtained the eclipse profiles by folding the All Sky Monitor light curve with the orbital period for different superorbital states. A dip feature, similar to the pre-eclipse dip in Her X-1, lying at orbital phase {approx}0.6-0.85, was discovered during the superorbital transition state. This indicates that the accretion disk has a bulge that absorbs considerable X-ray emission in the stream-disk interaction region. The dip width is anti-correlated with the flux, and this relation can be interpreted by the precessing tilted accretion disk scenario.

  2. Absorption dips at low x-ray energies in Cygnus X-1

    International Nuclear Information System (INIS)

    Murdin, P.

    1976-01-01

    Three more looks with the Copernicus satellite at Cygnus X-1 have produced four more examples of absorption dips, decreases in the 2 to 7 keV flux from Cygnus X-1 with an increase of spectral hardness consistent with photoelectric absorption (Mason et al 1974). The nine now seen, including one by OSO-7 (Li and Clark 1974), are listed in Table 1. Their phase in the spectroscopic binary HD 226868 is also listed, calculated from a newer ephemeris than that in Mason et al (1974), adding the radial velocities by Bolton (1975) and unpublished RGO radial velocities from the 1975 season. (These elements do not differ significantly from Bolton's

  3. Interacting binaries

    CERN Document Server

    Shore, S N; van den Heuvel, EPJ

    1994-01-01

    This volume contains lecture notes presented at the 22nd Advanced Course of the Swiss Society for Astrophysics and Astronomy. The contributors deal with symbiotic stars, cataclysmic variables, massive binaries and X-ray binaries, in an attempt to provide a better understanding of stellar evolution.

  4. Mass determination of Hercules X-1

    International Nuclear Information System (INIS)

    Bahcall, J.N.; Chester, T.J.

    1977-01-01

    The allowed range of masses for Hercules X-1 is calculated using the optical pulsation data of Middleditch and Nelson, a simple geometrical model for the optical pulsations, and Uhuru X-ray observations of the mass function and eclipse duration. For a specific set of assumptions, we obtain 0.6M/sub sun/ 1 < or =2.0M/sub sun/

  5. The 2-79 keV X-ray spectrum of the Circinus galaxy with NuSTAR, XMM-Newton, and Chandra: a fully Compton-thick active galactic nucleus

    International Nuclear Information System (INIS)

    Arévalo, P.; Bauer, F. E.; Puccetti, S.; Walton, D. J.; Fuerst, F.; Grefenstette, B. W.; Harrison, F. A.; Madsen, K. K.; Koss, M.; Boggs, S. E.; Craig, W. W.; Brandt, W. N.; Luo, B.; Brightman, M.; Christensen, F. E.; Comastri, A.; Gandhi, P.; Hailey, C. J.; Madejski, G.; Marinucci, A.

    2014-01-01

    The Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical parameters for the obscuring material. Chandra's high angular resolution allows a separation of nuclear and off-nuclear galactic emission. In the off-nuclear diffuse emission, we find signatures of strong cold reflection, including high equivalent-width neutral Fe lines. This Compton-scattered off-nuclear emission amounts to 18% of the nuclear flux in the Fe line region, but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton scattering by an optically thick torus, where the intrinsic spectrum is a power law of photon index Γ = 2.2-2.4, the torus has an equatorial column density of N H = (6-10) × 10 24 cm –2 , and the intrinsic AGN 2-10 keV luminosity is (2.3-5.1) × 10 42 erg s –1 . These values place Circinus along the same relations as unobscured AGNs in accretion rate versus Γ and L X versus L IR phase space. NuSTAR's high sensitivity and low background allow us to study the short timescale variability of Circinus at X-ray energies above 10 keV for the first time. The lack of detected variability favors a Compton-thick absorber, in line with the spectral fitting results.

  6. The 2-79 keV X-ray spectrum of the circinus galaxy with NuSTAR, XMM-Newton, and Chandra: a fully compton-thick active galactic nucleus

    DEFF Research Database (Denmark)

    Arévalo, P.; Bauer, F. E.; Puccetti, S.

    2014-01-01

    The Circinus galaxy is one of the closest obscured active galactic nuclei (AGNs), making it an ideal target for detailed study. Combining archival Chandra and XMM-Newton data with new NuSTAR observations, we model the 2-79 keV spectrum to constrain the primary AGN continuum and to derive physical......-nuclear emission amounts to 18% of the nuclear flux in the Fe line region, but becomes comparable to the nuclear emission above 30 keV. The new analysis no longer supports a prominent transmitted AGN component in the observed band. We find that the nuclear spectrum is consistent with Compton scattering...

  7. Trojan Binaries

    Science.gov (United States)

    Noll, K. S.

    2017-12-01

    The Jupiter Trojans, in the context of giant planet migration models, can be thought of as an extension of the small body populations found beyond Neptune in the Kuiper Belt. Binaries are a distinctive feature of small body populations in the Kuiper Belt with an especially high fraction apparent among the brightest Cold Classicals. The binary fraction, relative sizes, and separations in the dynamically excited populations (Scattered, Resonant) reflects processes that may have eroded a more abundant initial population. This trend continues in the Centaurs and Trojans where few binaries have been found. We review new evidence including a third resolved Trojan binary and lightcurve studies to understand how the Trojans are related to the small body populations that originated in the outer protoplanetary disk.

  8. 10 microsecond time resolution studies of Cygnus X-1

    Energy Technology Data Exchange (ETDEWEB)

    Wen, H. C. [Stanford Univ., CA (United States)

    1997-06-01

    Time variability analyses have been applied to data composed of event times of X-rays emitted from the binary system Cygnus X-1 to search for unique black hole signatures. The X-ray data analyzed was collected at ten microsecond time resolution or better from two instruments, the High Energy Astrophysical Observatory (HEAO) A-1 detector and the Rossi X-ray Timing Explorer (XTE) Proportional Counter Array (PCA). HEAO A-1 and RXTE/PCA collected data from 1977--79 and from 1996 on with energy sensitivity from 1--25 keV and 2--60 keV, respectively. Variability characteristics predicted by various models of an accretion disk around a black hole have been searched for in the data. Drop-offs or quasi-periodic oscillations (QPOs) in the Fourier power spectra are expected from some of these models. The Fourier spectral technique was applied to the HEAO A-1 and RXTE/PCA data with careful consideration given for correcting the Poisson noise floor for instrumental effects. Evidence for a drop-off may be interpreted from the faster fall off in variability at frequencies greater than the observed breaks. Both breaks occur within the range of Keplerian frequencies associated with the inner edge radii of advection-dominated accretion disks predicted for Cyg X-1. The break between 10--20 Hz is also near the sharp rollover predicted by Nowak and Wagoner`s model of accretion disk turbulence. No QPOs were observed in the data for quality factors Q > 9 with a 95% confidence level upper limit for the fractional rms amplitude at 1.2% for a 16 M⊙ black hole.

  9. New results from long-term observations of Cyg X-1

    International Nuclear Information System (INIS)

    Holt, S.S.; Boldt, E.A.; Serlemitsos, P.J.; Kaluzienski, L.J.

    1975-08-01

    Observations of Cyg X-1 between October 1974 and July 1975 reveal a persistent 5.6 day modulation of the 3- to 6-keV x-ray intensity, having a minimum in phase with superior conjunction of the HDE 226868 binary system. The modulation is found to be most pronounced just prior to the April--May 1975 increase of Cyg X-1, after which both the modulation and intensity are at their lowest values for the entire duration of the observations. These data imply that the x-ray emission from Cyg X-1 arises from the compact member of HDE 226868, and that the increase of April--May 1975 may have represented the depletion of accreting material which was not mixed into a cylindrically symmetric accretion disk about the compact member

  10. New results from long-term observations of Cygnus X-1

    International Nuclear Information System (INIS)

    Holt, S.S.; Boldt, E.A.; Serlemitsos, P.J.; Kaluzienski, L.J.

    1976-01-01

    Observations of Cyg X-1 between 1974 October and 1975 July reveal a persistent 5/subd/./sub /6 modulation of the 3--6 keV X-ray intensity, having a minimum in phase with superior conjunction of the HDE 226868 binary system. The modulation is found to be most pronounced just prior to the 1975 April--May increase of Cyg X-1, after which both the modulation and intensity are at their lowest values for the entire duration of the observations. These data imply that the X-ray emission from Cyg X-1 arises from the compact member of HDE 226868, and that the increase of 1975 April--May may have represented the depletion of accreting material which had not yet been mixed into a cylindrically symmetric accretion disk about the compact member

  11. New results from long-term observations of Cyg X-1

    International Nuclear Information System (INIS)

    Holt, S.S.; Boldt, E.A.; Serlemitsos, P.J.; Kaluzienski, L.J.

    1976-01-01

    Observations of Cyg X-1 between October 1974 and July 1975 reveal a persistent 5.6 day modulation of the 3 to 6 keV x-ray intensity, having a minimum in phase with superior conjunction of the HDE 226868 binary system. The modulation is found to be most pronounced just prior to the April to May 1975 increase of Cyg X-1, after which both the modulation and intensity are at their lowest values for the entire duration of the observations. These data imply that the x-ray emission from Cyg X-1 arises from the compact member of HDE 226868, and that the increase of April to May 1975 may have represented the depletion of accreting material which had not yet been mixed into a cylindrically symmetric accretion disk about the compact member

  12. ORNL Cray X1 evaluation status report

    International Nuclear Information System (INIS)

    Agarwal, P.K.; Alexander, R.A.; Apra, E.; Balay, S.; Bland, A.S; Colgan, J.; D'Azevedo, E.F.; Dongarra, J.J.; Dunigan, T.H. Jr.; Fahey, M.R.; Fahey, R.A.; Geist, A.; Gordon, M.; Harrison, R.J.; Kaushik, D.; Krishnakumar, M.; Luszczek, P.; Mezzacappa, A.; Nichols, J.A.; Nieplocha, J.; Oliker, L.; Packwood, T.; Pindzola, M.S.; Schulthess, T.C.; Vetter, J.S.; White III, J.B.; Windus, T.L.; Worley, P.H.; Zacharia, T.

    2004-01-01

    On August 15, 2002 the Department of Energy (DOE) selected the Center for Computational Sciences (CCS) at Oak Ridge National Laboratory (ORNL) to deploy a new scalable vector supercomputer architecture for solving important scientific problems in climate, fusion, biology, nanoscale materials and astrophysics. ''This program is one of the first steps in an initiative designed to provide U.S. scientists with the computational power that is essential to 21st century scientific leadership,'' said Dr. Raymond L. Orbach, director of the department's Office of Science. In FY03, CCS procured a 256-processor Cray X1 to evaluate the processors, memory subsystem, scalability of the architecture, software environment and to predict the expected sustained performance on key DOE applications codes. The results of the micro-benchmarks and kernel bench marks show the architecture of the Cray X1 to be exceptionally fast for most operations. The best results are shown on large problems, where it is not possible to fit the entire problem into the cache of the processors. These large problems are exactly the types of problems that are important for the DOE and ultra-scale simulation. Application performance is found to be markedly improved by this architecture: - Large-scale simulations of high-temperature superconductors run 25 times faster than on an IBM Power4 cluster using the same number of processors. - Best performance of the parallel ocean program (POP v1.4.3) is 50 percent higher than on Japan s Earth Simulator and 5 times higher than on an IBM Power4 cluster. - A fusion application, global GYRO transport, was found to be 16 times faster on the X1 than on an IBM Power3. The increased performance allowed simulations to fully resolve questions raised by a prior study. - The transport kernel in the AGILE-BOLTZTRAN astrophysics code runs 15 times faster than on an IBM Power4 cluster using the same number of processors. - Molecular dynamics simulations related to the phenomenon of

  13. ORNL Cray X1 evaluation status report

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, P.K.; Alexander, R.A.; Apra, E.; Balay, S.; Bland, A.S; Colgan, J.; D' Azevedo, E.F.; Dongarra, J.J.; Dunigan Jr., T.H.; Fahey, M.R.; Fahey, R.A.; Geist, A.; Gordon, M.; Harrison, R.J.; Kaushik, D.; Krishnakumar, M.; Luszczek, P.; Mezzacappa, A.; Nichols, J.A.; Nieplocha, J.; Oliker, L.; Packwood, T.; Pindzola, M.S.; Schulthess, T.C.; Vetter, J.S.; White III, J.B.; Windus, T.L.; Worley, P.H.; Zacharia, T.

    2004-05-01

    On August 15, 2002 the Department of Energy (DOE) selected the Center for Computational Sciences (CCS) at Oak Ridge National Laboratory (ORNL) to deploy a new scalable vector supercomputer architecture for solving important scientific problems in climate, fusion, biology, nanoscale materials and astrophysics. ''This program is one of the first steps in an initiative designed to provide U.S. scientists with the computational power that is essential to 21st century scientific leadership,'' said Dr. Raymond L. Orbach, director of the department's Office of Science. In FY03, CCS procured a 256-processor Cray X1 to evaluate the processors, memory subsystem, scalability of the architecture, software environment and to predict the expected sustained performance on key DOE applications codes. The results of the micro-benchmarks and kernel bench marks show the architecture of the Cray X1 to be exceptionally fast for most operations. The best results are shown on large problems, where it is not possible to fit the entire problem into the cache of the processors. These large problems are exactly the types of problems that are important for the DOE and ultra-scale simulation. Application performance is found to be markedly improved by this architecture: - Large-scale simulations of high-temperature superconductors run 25 times faster than on an IBM Power4 cluster using the same number of processors. - Best performance of the parallel ocean program (POP v1.4.3) is 50 percent higher than on Japan s Earth Simulator and 5 times higher than on an IBM Power4 cluster. - A fusion application, global GYRO transport, was found to be 16 times faster on the X1 than on an IBM Power3. The increased performance allowed simulations to fully resolve questions raised by a prior study. - The transport kernel in the AGILE-BOLTZTRAN astrophysics code runs 15 times faster than on an IBM Power4 cluster using the same number of processors. - Molecular dynamics simulations

  14. X1X1X2X2/X1X2Y sex chromosome systems in the Neotropical Gymnotiformes electric fish of the genus Brachyhypopomus

    Directory of Open Access Journals (Sweden)

    Adauto Lima Cardoso

    2015-06-01

    Full Text Available Several types of sex chromosome systems have been recorded among Gymnotiformes, including male and female heterogamety, simple and multiple sex chromosomes, and different mechanisms of origin and evolution. The X1X1X2X2/X1X2Y systems identified in three species of this order are considered homoplasic for the group. In the genus Brachyhypopomus, only B. gauderio presented this type of system. Herein we describe the karyotypes of Brachyhypopomus pinnicaudatus and B. n. sp. FLAV, which have an X1X1X2X2/X1X2Y sex chromosome system that evolved via fusion between an autosome and the Y chromosome. The morphology of the chromosomes and the meiotic pairing suggest that the sex chromosomes of B. gauderio and B. pinnicaudatus have a common origin, whereas in B . n. sp. FLAV the sex chromosome system evolved independently. However, we cannot discard the possibility of common origin followed by distinct processes of differentiation. The identification of two new karyotypes with an X1X1X2X2/X1X2Y sex chromosome system in Gymnotiformes makes it the most common among the karyotyped species of the group. Comparisons of these karyotypes and the evolutionary history of the taxa indicate independent origins for their sex chromosomes systems. The recurrent emergence of the X1X1X2X2/X1X2Y system may represent sex chromosomes turnover events in Gymnotiformes.

  15. Long-term studies with the Ariel-5 asm. 1: Her X-1, Vela X-1 and Cen X-3. [periodic variations

    Science.gov (United States)

    Holt, S. S.; Kaluzienski, L. J.; Boldt, E. A.; Serlemitsos, P. J.

    1978-01-01

    Twelve hundred days of 3-6 keV X-ray data from Her X-1, Vela X-1 and Cen X-3 accumulated with the Ariel-5 all-sky monitor are interrogated. The binary periodicities of all three can be clearly observed, as can the approximately 35-d variation of Her X-1, for which we can refine the period to 34.875 plus or minus .030-d. No such longer-term periodicity less than 200-d is observed from Vela X-1. The 26.6-d low-state recurrence period for Cen X-3 previously suggested is not observed, but a 43.0-d candidate periodicity is found which may be consistent with the precession of an accretion disk in that system. The present results are illustrative of the long-term studies which can be performed on approximately 50 sources over a temporal base which will ultimately extend to at least 1800 days.

  16. Long term variability of Cygnus X-1. VI. Energy-resolved X-ray variability 1999-2011

    NARCIS (Netherlands)

    Grinberg, V.; Pottschmidt, K.; Böck, M.; Schmid, C.; Nowak, M.A.; Uttley, P.; Tomsick, J.A.; Rodriguez, J.; Hell, N.; Markowitz, A.; Bodaghee, A.; Cadolle Bel, M.; Rothschild, R.E.; Wilms, J.

    2014-01-01

    We present the most extensive analysis of Fourier-based X-ray timing properties of the black hole binary Cygnus X-1 to date, based on 12 years of bi-weekly monitoring with RXTE from 1999 to 2011. Our aim is a comprehensive study of timing behavior across all spectral states, including the elusive

  17. Search for gravitational waves from Scorpius X-1 in the first Advanced LIGO observing run with a hidden Markov model

    NARCIS (Netherlands)

    Abbott, B. P.; Abbott, R.; Abbott, D.; Acernese, F.; Ackley, K.; Adams, C.; Phythian-Adams, A.T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agatsuma, K.; Aggarwal, N.T.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G; Allocca, A.; Almoubayyed, H.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, R.D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bawaj, M.; Bazzan, M.; Becsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Etienne, Z. B.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, D J; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blari, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, J.G.; Bohe, A.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, A.D.; Brown, D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderon; Callister, T. A.; Calloni, E.; Camp, J. B.; Canepa, M.; Canizares, P.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Carney, M. F.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglia, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, D. S.; Charlton, P.; Chassande-Mottin, E.; Chatterjee, D.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y; Cheng, H. -P.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S. S. Y.; Chung, A. K. W.; Chung, S.; Ciani, G.; Ciolfi, R.; Cirelli, C. E.; Cirone, A.; Clara, F.; Clark, J. A.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P. -F.; Colla, A.; Collette, C. G.; Cominsky, L. R.; Constancio, M., Jr.; Conti, L.; Cooper, S. J.; Corban, P.; Corbitt, T. R.; Corley, K. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J. -P.; Countryman, S. T.; Couvares, P.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, Laura; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Costa, C. F. Da Silva; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Davis, D.; Daw, E. J.; Day, B.; De, S.; Debra, D.; Deelman, E; Degallaix, J.; De laurentis, M.; Deleglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.A.; Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devenson, J.; Devine, R. C.; Dhurandhar, S.; Diaz, M. C.; Di Fiore, L.; Giovanni, M. Di; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Renzo, F.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Alvarez, M. Dovale; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Duncan, J.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H. -B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fehrmann, H.; Feicht, J.; Fejer, M. M.; Fernandez-Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M; Fong, H.; Forsyth, P. W. F.; Forsyth, S. S.; Fournier, J. -D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gabel, M.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Ganija, M. R.; Gaonkar, S. G.; Garufi, F.; Gaudio, S.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, D.J.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.P.; Glover, L.; Goetz, E.; Goetz, R.; Gomes, A.S.P.; Gonzalez, Idelmis G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Lee-Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.M.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Gruning, P.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannuksela, O. A.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Haster, C. -J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.A.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Horst, C.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Intini, G.; Isa, H. N.; Isac, J. -M.; Isi, M.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jimenez-Forteza, F.; Johnson, W.; Jones, I.D.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katolik, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kawabe, K.; Kefelian, F.; Keitel, D.; Kemball, A. J.; Kennedy, R.E.; Kent, C.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan., S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, W.; Kim, S.W.; Kim, Y.M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kirchhoff, R.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kramer, C.; Kringel, V.; Krishnan, B.; Krolak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kumar, S.; Kuo, L.; Kutynia, A.; Kwang-Cheol, S.; Lackey, B. D.; Lai, K. H.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lee, C.H.; Lee, K.H.; Lee, M.H.; Lee, W. H.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Liu, J.; Lockerbie, N. A.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lovelace, G.; Luck, H.; Lumaca, D.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana Hernandez, I.; Magana-Sandoval, F.; Magana Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marka, S.; Marka, Z.; Markakis, C.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mayani, R.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B.C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, S.D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muniz, E. A. M.; Murray, P.G.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nelemans, G.; Nelson, T. J. N.; Gutierrez-Neri, M.; Nery, M.; Neunzert, A.; Newport, J. M.; Newton, G.; Ng, K. K. Y.; Nguyen, T. T.; Nichols, D.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Ormiston, R.; Ortega, L. F.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Page, M. A.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pang, B.; Pang, P. T. H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.S; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Castro-Perez, J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Porter, E. K.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Purrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Ramirez, K. E.; Rapagnani, P.; Raymond, V.; Razzano, M.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Ricker, P. M.; Rieger, S.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romel, C. L.; Romie, J. H.; Rosinska, D.; Ross, M. P.; Rowan, S.; Rudiger, A.; Ruggi, P.; Ryan, K.; Rynge, M.; Sachdev, Perminder S; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheuer, J.; Schmidt, E.; Schmidt, J; Schmidt, P.; Schnabel, R.B.; Schofield, R. M. S.; Schonbeck, A.; Schreiber, K.E.C.; Schuette, D.; Schulte, B. W.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Seidel, E.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shaffer, T. J.; Shah, A.; Shahriar, M. S.; Shao, L.P.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, António Dias da; Singer, A; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, R. J. E.; Smith, R. J. E.; Son, E. J.; Sonnenberg, J. A.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Stratta, G.; Strigin, S. E.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepanczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tapai, M.; Taracchini, A.; Taylor, J. A.; Taylor, W.R.; Theeg, T.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torrie, C. I.; Toyra, D.; Travasso, F.; Traylor, G.; Trifiro, D.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahi, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; Van Beuzekom, Martin; van den Brand, J. F. J.; Van Den Broeck, C.F.F.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasuth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P.J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Vicere, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J. -Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, MT; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, M.; Wang, Y. -F.; Wang, Y. -F.; Ward, L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L. -W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Wessels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Williams, D.; Williams, D.R.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, G.W.K.; Worden, J.; Wright, J.L.; Wu, D.S.; Wu, G.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, Hang; Yu, Haocun; Yvert, M.; Zadrozny, A.; Zanolin, M.; Zelenova, T.; Zendri, J. -P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y. -H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.; Suvorova, S.; Moran, W.; Evans, J.R.

    2017-01-01

    Results are presented from a semicoherent search for continuous gravitational waves from the brightest low-mass X-ray binary, Scorpius X-1, using data collected during the first Advanced LIGO observing run. The search combines a frequency domain matched filter (Bessel-weighted F-statistic) with a

  18. The Reflection Component from Cygnus X-1 in the Soft State Measured by NuSTAR and Suzaku

    DEFF Research Database (Denmark)

    Tomsick, John A.; Nowak, Michael A.; Parker, Michael

    2014-01-01

    The black hole binary Cygnus X-1 was observed in late-2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ~1-300 keV range. The source was in the soft state with a multi-temperature blackbody, power-law, and reflection components along...

  19. Optical observations of binary X-ray sources

    International Nuclear Information System (INIS)

    Boynton, P.E.

    1975-01-01

    The contribution to the recent progress in astronomy made by optical observations is pointed out. The optical properties of X-ray sources help to establish the physical nature of these objects. The current observational evidence on the binary X-ray sources HZ Her/Her X-1 and HDE 226868/Cyg X-1 is reported. (P.J.S.)

  20. Gas phase UV and IR absorption spectra of CxF2x+1CHO (x=1-4)

    DEFF Research Database (Denmark)

    Hashikawa, Y; Kawasaki, M; Waterland, RL

    2004-01-01

    The UV and IR spectra of CxF2x+1 CHO (x = 1-4) were investigated using computational and experimental techniques. CxF2x+1CHO (x = 1-4) have broad UV absorption features centered at 300-310 nm. The maximum absorption cross-section increases significantly and shifts slightly to the red with increased...

  1. Alternative Explanations for Extreme Supersolar Iron Abundances Inferred from the Energy Spectrum of Cygnus X-1

    Science.gov (United States)

    Tomsick, John A.; Parker, Michael L.; García, Javier A.; Yamaoka, Kazutaka; Barret, Didier; Chiu, Jeng-Lun; Clavel, Maïca; Fabian, Andrew; Fürst, Felix; Gandhi, Poshak; Grinberg, Victoria; Miller, Jon M.; Pottschmidt, Katja; Walton, Dominic J.

    2018-03-01

    Here we study a 1–200 keV energy spectrum of the black hole binary Cygnus X-1 taken with NuSTAR and Suzaku. This is the first report of a NuSTAR observation of Cyg X-1 in the intermediate state, and the observation was taken during the part of the binary orbit where absorption due to the companion’s stellar wind is minimal. The spectrum includes a multi-temperature thermal disk component, a cutoff power-law component, and relativistic and nonrelativistic reflection components. Our initial fits with publicly available constant density reflection models (relxill and reflionx) lead to extremely high iron abundances (>9.96 and {10.6}-0.9+1.6 times solar, respectively). Although supersolar iron abundances have been reported previously for Cyg X-1, our measurements are much higher and such variability is almost certainly unphysical. Using a new version of reflionx that we modified to make the electron density a free parameter, we obtain better fits to the spectrum even with solar iron abundances. We report on how the higher density ({n}e=({3.98}-0.25+0.12)× {10}20 cm‑3) impacts other parameters such as the inner radius and inclination of the disk.

  2. Binary effectivity rules

    DEFF Research Database (Denmark)

    Keiding, Hans; Peleg, Bezalel

    2006-01-01

    is binary if it is rationalized by an acyclic binary relation. The foregoing result motivates our definition of a binary effectivity rule as the effectivity rule of some binary SCR. A binary SCR is regular if it satisfies unanimity, monotonicity, and independence of infeasible alternatives. A binary...

  3. e-EVN radio detection of Aql X-1 in outburst

    Science.gov (United States)

    Tudose, V.; Paragi, Z.; Yang, J.; Miller-Jones, J. C. A.; Fender, R.; Garrett, M.; Rushton, A.; Spencer, R.

    2013-06-01

    The neutron star X-ray binary Aql X-1 is currently in outburst (ATel #5114, #5117, #5129, #5136, #5148). Using the European VLBI Network (e-EVN) we observed Aql X-1 at 5 GHz in two time-slots: 2013 June 18 between 19:48 - 20:36 UT (MJD 56461.825 - 56461.858), and 2013 June 19 between 02:53 - 05:54 UT (MJD 56462.120 - 56462.246). The two datasets were combined together and then calibrated. The participating radio telescopes were: Effelsberg (Germany), Jodrell Bank Mk2 (UK), Medicina (Italy), Noto (Italy), Onsala 25m (Sweden), Torun (Poland), Yebes (Spain), Westerbork Synthesis Radio Telescope (Netherlands), Shanghai (China), Hartebeesthoek (South Africa).

  4. Observation of hard X-rays line emission from Her X-1

    Energy Technology Data Exchange (ETDEWEB)

    Polcaro, V.F.; Bazzano, A.; la Padula, C.; Ubertini, P.; Vialetto, G.; Manchanda, R.K.; Damle, S.V.

    1982-04-01

    We present the results of a hard X-ray measurement of the binary source Her X-1, carried out with a balloon borne X-ray telescope consisting of two Multiwire Proportional Counters, having 900 cm/sup 2/ sensitive area each and spectral resolution of 15% and 24% FWHM respectively at 60 keV. The source was observed during the 'Mid-on' state. Our data confirm the previously reported high energy emission line overimposed on the low energy thermal spectrum.

  5. The Extreme Spin of the Black Hole in Cygnus X-1

    Science.gov (United States)

    Gou, Lijun; McClintock, Jeffrey E.; Reid, Mark J.; Orosz, Jerome A.; Steiner, James F.; Narayan, Ramesh; Xiang, Jingen; Remillard, Ronald A.; Arnaud, Keith A.; Davis, Shane W.

    2011-01-01

    The compact primary in the X-ray binary Cygnus X-1 was the first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, and for the orbital inclination angle of the binary. Building on these results, which are based on our favored (asynchronous) dynamical model, we have measured the radius of the inner edge of the black hole s accretion disk by fitting its thermal continuum spectrum to a fully relativistic model of a thin accretion disk. Assuming that the spin axis of the black hole is aligned with the orbital angular momentum vector, we have determined that Cygnus X-1 contains a near-extreme Kerr black hole with a spin parameter a* > 0.95 (3(sigma)). For a less probable (synchronous) dynamical model, we find a. > 0.92 (3 ). In our analysis, we include the uncertainties in black hole mass, orbital inclination angle, and distance, and we also include the uncertainty in the calibration of the absolute flux via the Crab. These four sources of uncertainty totally dominate the error budget. The uncertainties introduced by the thin-disk model we employ are particularly small in this case given the extreme spin of the black hole and the disk s low luminosity.

  6. When is f(x1,x2,... ,xn)

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    When is f(x1,x2,... ,xn) = u1(x1) + u2(x2) +···+ un(xn)? ... (i) there exist non-zero integers p1,p2,... ,pk such that ..... probability measure for the countable collection of functions 1Ai , i = 1, 2, 3,. .... For question (B) a sufficient condition is that.

  7. A possible very high energy gamma-ray burst from Hercules X-1

    International Nuclear Information System (INIS)

    Vishwanath, P.R.; Bhat, P.N.; Ramanamurthy, P.V.; Sreekantan, B.V.

    1989-01-01

    A large increase is observed in the trigger rate in the direction of Hercules X-1 in the Atmospheric Cerenkov array at Pachmarhi, India. The burst lasted from 2147 UT to 2201 UT on April 11, 1986. The accidental coincidence rate did not show any increase during the burst. Barring any electronic noise or celestial or terrestrial optical phenomenon with time structure similar to that of atmospheric Cerenkov phenomenon, the increase is ascribed to TeV gamma rays from Her X-1. The number of gamma-ray events during the burst amounted to about 54 percent of the cosmic-ray flux, resulting in a 42-sigma effect. This is the largest TeV gamma-ray signal seen from any source till now. The time-averaged flux for the burst period is 1.8 x 10 photons/sq cm per s above a threshold energy of 0.4 TeV, which results in a luminosity of 1.8 x 10 to the 37 ergs/s. The burst took place at the end of the 'high on' state in the 35-day cycle of the Her X-1 binary system indicating accretion disk as the possible production site. 14 refs

  8. X rays from radio binaries

    International Nuclear Information System (INIS)

    Apparao, K.M.V.

    1977-01-01

    Reference is made to the radio binary systems CC Cas, AR Lac, β Per (Algol), β Lyr, b Per and Cyg X-1. It is stated that a thermal interpretation of the radiation from Algol requires a much larger x-ray flux than the observed value of 3.8 x 10 -11 erg/cm 2 /sec/keV in the 2 to 6 keV energy range. Observations of some non-thermal flares, together with the small size of the radio source in Algol, indicate that the radio emission is non-thermal in nature. The radio emission is interpreted as synchrotron radiation and it is suggested that the observed x-ray emission is due to inverse Compton scattering of the light of the primary star by the radio electrons. The x-ray emission from other radio binaries is also calculated using this model. The energy for the radio electrons can arise from annihilation of magnetic lines connecting the binary stars, twisted by the rotation of the stars. (U.K.)

  9. Upper Limits on Gravitational Waves from Scorpius X-1 from a Model-based Cross-correlation Search in Advanced LIGO Data

    NARCIS (Netherlands)

    Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bawaj, M.; Bazzan, M.; Becsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderon; Callister, T. A.; Calloni, E.; Camp, J. B.; Canepa, M.; Canizares, P.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Carney, M. F.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglia, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chatterjee, D.; Chatziioannou, K.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, H. -P.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, A. K. W.; Chung, S.; Ciani, G.; Ciolfi, R.; Cirelli, C. E.; Cirone, A.; Clara, F.; Clark, J. A.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P. -F.; Colla, A.; Collette, C. G.; Cominsky, L. R.; Constancio, M., Jr.; Conti, L.; Cooper, S. J.; Corban, P.; Corbitt, T. R.; Corley, K. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J. -P.; Countryman, S. T.; Couvares, P.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davis, D.; Daw, E. J.; Day, B.; De, S.; Debra, D.; Deelman, E.; Degallaix, J.; De laurentis, M.; Deleglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devenson, J.; Devine, R. C.; Dhurandhar, S.; Diaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Renzo, F.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Alvarez, M. Dovale; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Duncan, J.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H. -B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Eisenstein, R. A.; Essick, R. C.; Etienne, Z. B.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fehrmann, H.; Feicht, J.; Fejer, M. M.; Fernandez-Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Forsyth, P. W. F.; Forsyth, S. S.; Fournier, J. -D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gabel, M.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Galloway, D. K.; Gammaitoni, L.; Ganija, M. R.; Gaonkar, S. G.; Garufi, F.; Gaudio, S.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, D.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glover, L.; Goetz, E.; Goetz, R.; Gomes, S.; Gonzlez, G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Gruning, P.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannuksela, O. A.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Haster, C. -J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Horst, C.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Intini, G.; Isa, H. N.; Isac, J. -M.; Isi, M.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jimenez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katolik, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kawabe, K.; Kefelian, F.; Keitel, D.; Kemball, A. J.; Kennedy, R.; Kent, C.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, W.; Kim, W. S.; Kim, Y. -M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kirchhoff, R.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Krmer, C.; Kringel, V.; Krishnan, B.; Krolak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kumar, S.; Kuo, L.; Kutynia, A.; Kwang, S.; Lackey, B. D.; Lai, K. H.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, H. W.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Liu, J.; Lo, R. K. L.; Lockerbie, N. A.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Luck, H.; Lumaca, D.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Hernandez, I. Magana; Magana-Sandoval, F.; Zertuche, L. Magaa; Magee, R. M.; Majorana, E.; Maksimovic, I.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marka, S.; Marka, Z.; Markakis, C.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mayani, R.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muniz, E. A. M.; Murray, P. G.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Nery, M.; Neunzert, A.; Newport, J. M.; Newton, G.; Ng, K. K. Y.; Nguyen, T. T.; Nichols, D.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Ormiston, R.; Ortega, L. F.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Page, M. A.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pang, B.; Pang, P. T. H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perez, C. J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Porter, E. K.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Prrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Ramirez, K. E.; Rapagnani, P.; Raymond, V.; Razzano, M.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Ricker, P. M.; Rieger, S.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romel, C. L.; Romie, J. H.; Rosinska, D.; Ross, M. P.; Rowan, S.; Ruediger, A.; Ruggi, P.; Ryan, K.; Rynge, M.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheuer, J.; Schmidt, E.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schoenbeck, A.; Schoenbeck, A.; Schreiber, E.; Schuette, D.; Schulte, B. W.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Seidel, E.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shaffer, T. J.; Shah, A. A.; Shahriar, M. S.; Shao, L.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, R. J. E.; Smith, R. J. E.; Son, E. J.; Sonnenberg, J. A.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Stratta, G.; Strigin, S. E.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepanczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tapai, M.; Taracchini, A.; Taylor, J. A.; Taylor, R.; Theeg, T.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torrie, C. I.; Tayra, D.; Travasso, F.; Traylor, G.; Trifiro, D.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahi, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; Van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasuth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Vicere, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J. -Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, M.; Wang, Y. -F.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L. -W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Wessels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, K. W. K.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, Hang; Yu, Haocun; Yvert, M.; Zanolin, M.; Zelenova, T.; Zendri, J. -P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y. -H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.; Steeghs, D.; Wang, L.

    2017-01-01

    We present the results of a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using data from the first Advanced LIGO observing run. The search method uses details of the modeled, parametrized continuous signal to combine coherently data separated by

  10. BChPT x 1/Nc: masses and currents

    Energy Technology Data Exchange (ETDEWEB)

    Goity, Jose L. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hampton Univ., Hampton, VA (United States); Fernando, Ishara P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hampton Univ., Hampton, VA (United States)

    2018-04-01

    A summary of the implementation of the combined BChPT X 1/Nc expansion for three flavors is presented, along with its applications to the octet and decuplet baryon masses, SU(3) charges and axial couplings.

  11. X-1A in flight with flight data superimposed

    Science.gov (United States)

    1953-01-01

    This photo of the X-1A includes graphs of the flight data from Maj. Charles E. Yeager's Mach 2.44 flight on December 12, 1953. (This was only a few days short of the 50th anniversary of the Wright brothers' first powered flight.) After reaching Mach 2.44, then the highest speed ever reached by a piloted aircraft, the X-1A tumbled completely out of control. The motions were so violent that Yeager cracked the plastic canopy with his helmet. He finally recovered from a inverted spin and landed on Rogers Dry Lakebed. Among the data shown are Mach number and altitude (the two top graphs). The speed and altitude changes due to the tumble are visible as jagged lines. The third graph from the bottom shows the G-forces on the airplane. During the tumble, these twice reached 8 Gs or 8 times the normal pull of gravity at sea level. (At these G forces, a 200-pound human would, in effect, weigh 1,600 pounds if a scale were placed under him in the direction of the force vector.) Producing these graphs was a slow, difficult process. The raw data from on-board instrumentation recorded on oscillograph film. Human computers then reduced the data and recorded it on data sheets, correcting for such factors as temperature and instrument errors. They used adding machines or slide rules for their calculations, pocket calculators being 20 years in the future. Three second generation Bell Aircraft Corporations X-1s were built, though four were requested. They were the X-1A (48-1384); X-1B (48-1385); X-1C (canceled and never built); X-1D (48-1386). These aircraft were similar to the X-1s, except they were five feet longer, had conventional canopies, and were powered by Reaction Motors, Inc. XLR11-RM-5 rocket engines. The RM-5, like the previous engines, had no throttle and was controlled by igniting one or more of the four thrust chambers at will. The original program outline called for the X-1A and X-1B to be used for dynamic stability and air loads investigations. The X-1D was to be used

  12. Ultraviolet, X-ray, and infrared observations of HDE 226868 equals Cygnus X-1

    Science.gov (United States)

    Treves, A.; Chiappetti, L.; Tanzi, E. G.; Tarenghi, M.; Gursky, H.; Dupree, A. K.; Hartmann, L. W.; Raymond, J.; Davis, R. J.; Black, J.

    1980-01-01

    During April, May, and July of 1978, HDE 226868, the optical counterpart of Cygnus X-1, was repeatedly observed in the ultraviolet with the IUE satellite. Some X-ray and infrared observations have been made during the same period. The general shape of the spectrum is that expected from a late O supergiant. Strong absorption features are apparent in the ultraviolet, some of which have been identified. The equivalent widths of the most prominent lines appear to be modulated with the orbital phase. This modulation is discussed in terms of the ionization contours calculated by Hatchett and McCray, for a binary X-ray source in the stellar wind of the companion.

  13. X-1E launch from B-50 mothership

    Science.gov (United States)

    1950-01-01

    Beginning in 1946, two XS-1 experimental research aircraft (later redesignated X-1s) conducted pioneering tests at Muroc Army Air Field (now Edwards Air Force Base) in California to obtain flight data on conditions in the transonic speed range. These early tests culminated on October 14, 1947, in the first piloted flight faster than Mach 1.0, the speed of sound. During November, 1947, the Air Force authorized studies that led to a contract (W-33-038-ac-20062) with Bell Aircraft to build four (later three) improved X-1 aircraft (the X-1C being cancelled). Designated X-1A (#48-1384), X-1B (#48-1385), and X-1D (#48-1386), the airplanes were ready by late 1950. The aircraft were about five feet longer and 2,500 lbs. heavier than the original X-craft planes. They used the 8-percent wing like the earlier X-craft. The D-model had a low-pressure turbo-pump and the B model was fitted with a prototype hydrogen peroxide reaction control system for later aircraft to use in exoatmospheric research flights. Access was through a lift-off canopy. The planes were finished in their bare metal color and white. The X-1D was ready first, but on what was intended to be its second flight (August 22, 1951) it was jettisoned and crashed at Muroc after an aerial explosion while still mated to its mother (B-50A [#46-006A]) ship. The long-delayed X-1 #3 airplane with the turbine pump was finally completed for the NACA in 1951. It made its first glide flight on July 20, 1951, with NACA pilot Joseph Cannon. Its second and final captive flight was on November 9, 1951. It was destroyed on the ground by an explosion and fire along with its B-50A mother ship while attempting to jettison fuel. The X-1A arrived at Muroc in January, 1953 and had its first powered flight on February 21, 1953. On December 8, 1953 with Yeager as pilot, the aircraft investigated high-speed stability and control issues. The X-1A was turned over to the NACA, but was lost to aerial explosion on August 8, 1955, shortly before

  14. Studies of optical pulsations from HZ Herculis/Hercules X-1: A determination of the mass of the neutron star

    International Nuclear Information System (INIS)

    Middleditch, J.; Nelson, J.

    1976-01-01

    In 500 hours of optical observations of this binary system we have repeatedly detected optical pulsations at the 0.1--0.3 percent level. These pulsations are present only for particular well-defined values of the binary and 35-day phases. Position of the pulsation-emitting regions, projected onto the orbital plane, have been measured, and three distinct regions have been resolved. A simple model is put forth which accounts for the observed binary behavior, which gives a direct determination of the mass ratio, M/sub HZHer//M/sub HerX-/ 1 =1.68 +- 0.10 and which establishes that the spin of the pulsar is prograde. Additionally, it is shown that Hz Her fills its Roche lobe. Using the above, the known X-ray eclipse duration, and the mass function, we calculate the orbital inclination to be i=87degree +- 3degree and the masses to be M/sub HerX-/ 1 =1.30 +- 0.14 M/sub sun/ and M/sub HZHer/=2.18 +- 0.11 M/sub sun/

  15. Is Cygus X-1 a chaotic dynamical system?

    International Nuclear Information System (INIS)

    Unno, Wasaburo; Yoneyama, Tadaoki; Urata, Kenji; Masaki, Isao; Kondo, Masa-aki; Inoue, Hajime.

    1990-01-01

    X-ray data of Cyg X-1 observed by the Tenma satellite were analyzed to determine whether Cyg X-1 is a chaotic dynamical system of low dimension. Since Poisson noise disturbs the determination of the attractor dimension of the system, comparative studies were carried out for the Cyg X-1 data relative to artificial data of purely stochastic Poisson noise and to a Lorenz attractor plus noise. The attractor dimension was searched using trajectories of time series data in phase space, the dimension of which was varied up to 21. The relation between the attractor dimension and the phase-space dimension for the Cyg X-1 data starts to deviate from that of noise data from a phase-space dimension of about 7, showing the presence of an attractor with a dimension of about 7 or less. Though three positive Lyapunov exponents were calculated, they are too small (∼10 -2 ) to prove with certainty that the Cyg X-1 attractor should be a strange attractor. (author)

  16. Solving a binary puzzle

    NARCIS (Netherlands)

    Utomo, P.H.; Makarim, R.H.

    2017-01-01

    A Binary puzzle is a Sudoku-like puzzle with values in each cell taken from the set {0,1} {0,1}. Let n≥4 be an even integer, a solved binary puzzle is an n×n binary array that satisfies the following conditions: (1) no three consecutive ones and no three consecutive zeros in each row and each

  17. Optical pulsation from the HZ Her/Her X-1 system

    International Nuclear Information System (INIS)

    Chester, T.J.

    1977-01-01

    A theoretical model for the observed optical pulsation from the x-ray binary HZ Her/Her X-1 is presented. Its foundation is a general computer code for an x-ray illuminated stellar atmosphere. Detailed results are given for several atmospheres applicable to HZ Her. A formalism is developed to calculate the amount of pulsed optical radiation emergent from these atmospheres if they are exposed to pulsed x rays. This formalism is used to calculate the pulsed and unpulsed optical light curves for HZ Her. The calculated optical pulsation agrees with the observed amplitude. A nonuniform x-ray beam can cause the amplitude and velocity of the optical pulsation to vary by more than a factor of two for fixed system parameters. The presence of soft x rays (0.1 to 1 keV) can significantly affect the calculated pulsation amplitude. The model places explicit limits on the system parameters; in particular, if corotation is assumed, 0.8 M/sub sun/ less than or equal to M/sub Her X-1/ less than or equal to 1.7 M/sub sun/

  18. The Nature and Cause of Spectral Variability in LMC X-1

    Science.gov (United States)

    Ruhlen, L.; Smith, D. M.; Scank, J. H.

    2011-01-01

    We present the results of a long-term observation campaign of the extragalactic wind-accreting black-hole X-ray binary LMC X-1, using the Proportional Counter Array on the Rossi X-Ray Timing Explorer (RXTE). The observations show that LMC X-1's accretion disk exhibits an anomalous temperature-luminosity relation. We use deep archival RXTE observations to show that large movements across the temperature-luminosity space occupied by the system can take place on time scales as short as half an hour. These changes cannot be adequately explained by perturbations that propagate from the outer disk on a viscous timescale. We propose instead that the apparent disk variations reflect rapid fluctuations within the Compton up-scattering coronal material, which occults the inner parts of the disk. The expected relationship between the observed disk luminosity and apparent disk temperature derived from the variable occultation model is quantitatively shown to be in good agreement with the observations. Two other observations support this picture: an inverse correlation between the flux in the power-law spectral component and the fitted inner disk temperature, and a near-constant total photon flux, suggesting that the inner disk is not ejected when a lower temperature is observed.

  19. Eclipsing binaries in open clusters

    DEFF Research Database (Denmark)

    Southworth, John; Clausen, J.V.

    2006-01-01

    Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August......Stars: fundamental parameters - Stars : binaries : eclipsing - Stars: Binaries: spectroscopic - Open clusters and ass. : general Udgivelsesdato: 5 August...

  20. Low energy gamma rays emitted by Sco X-1

    International Nuclear Information System (INIS)

    Bui-Van, A.; Martin, I.M.

    1975-01-01

    Sco X-1 was observed on a balloon flight launched from Sao Jose dos Campos, S.P., Brazil, on December 20, 1974. A 3 sigma excess of the raw count rate, covering the energy range 0.2 to 5.0 MeV, was found during the transit of the source. A power-law spectrum provided an adequate fit to the data. Although it was difficult to separate the contribution of the universal diffuse component, the existence of hard-component in the spectrum of Sco X-1 could indicate the presence of matter hotter than previously deduced from soft X-ray observations [pt

  1. Low-energy gamma rays from Cygnus X-1

    International Nuclear Information System (INIS)

    Roques, J.P.; Mandrou, P.; Lebrun, F.; Paul, J.

    1985-08-01

    Cyg X-1 was observed by the CESR balloon borne telescope OPALE, in June 1976. The high-energy spectrum of the source, which was in its ''superlow state'', was seen to extend well beyond 1 MeV. In this paper, the observed low-energy γ-ray component of Cyg X-1 is compared with the predictions of recent models involving accretion onto a stellar black hole, and including a possible contribution from the pair-annihilation 511 keV γ-ray line

  2. Radio emission from the X-ray pulsar Her X-1: a jet launched by a strong magnetic field neutron star?

    Science.gov (United States)

    van den Eijnden, J.; Degenaar, N.; Russell, T. D.; Miller-Jones, J. C. A.; Wijnands, R.; Miller, J. M.; King, A. L.; Rupen, M. P.

    2018-01-01

    Her X-1 is an accreting neutron star (NS) in an intermediate-mass X-ray binary. Like low-mass X-ray binaries (LMXBs), it accretes via Roche lobe overflow, but similar to many high-mass X-ray binaries containing a NS; Her X-1 has a strong magnetic field and slow spin. Here, we present the discovery of radio emission from Her X-1 with the Very Large Array. During the radio observation, the central X-ray source was partially obscured by a warped disc. We measure a radio flux density of 38.7 ± 4.8 μJy at 9 GHz but cannot constrain the spectral shape. We discuss possible origins of the radio emission, and conclude that coherent emission, a stellar wind, shocks and a propeller outflow are all unlikely explanations. A jet, as seen in LMXBs, is consistent with the observed radio properties. We consider the implications of the presence of a jet in Her X-1 on jet formation mechanisms and on the launching of jets by NSs with strong magnetic fields.

  3. Light curve and pulse profile of the x-ray pulsar Vela X-1

    International Nuclear Information System (INIS)

    Nagase, Fumiaki; Hayakawa, Satio; Makino, Fumiyoshi; Sato, Naohisa; Makishima, Kazuo.

    1983-01-01

    The following properties of the X-ray binary pulsar Vela X-1 are presented by reference to its observations in March 1980. The light curve shows a high state and a low state in the first and second halves of an orbital period, respectively, but they may rather be defined as a soft state and hard state, respectively, since the intensity above 9 keV does not appreciably change between these two states. The energy spectra in these states indicate the presence of circumstellar absorption. The pulse profiles at high (9-22 keV) and low (1-9 keV) energies are different, indicating the absorption by cold matter which is probably in the accretion column. The absorber which is responsible for the soft and hard states is attributed to the stellar wind whose flow pattern is consistent with that obtained from optical absorption spectra. The orbital period is obtained by a combined analysis of X-ray data since 1972. No appreciable change of the period gives a constraint on the dynamical behavior of the binary system. (author)

  4. Modelling hard and soft states of Cygnus X-1 with propagating mass accretion rate fluctuations

    Science.gov (United States)

    Rapisarda, S.; Ingram, A.; van der Klis, M.

    2017-12-01

    We present a timing analysis of three Rossi X-ray Timing Explorer observations of the black hole binary Cygnus X-1 with the propagating mass accretion rate fluctuations model PROPFLUC. The model simultaneously predicts power spectra, time lags and coherence of the variability as a function of energy. The observations cover the soft and hard states of the source, and the transition between the two. We find good agreement between model predictions and data in the hard and soft states. Our analysis suggests that in the soft state the fluctuations propagate in an optically thin hot flow extending up to large radii above and below a stable optically thick disc. In the hard state, our results are consistent with a truncated disc geometry, where the hot flow extends radially inside the inner radius of the disc. In the transition from soft to hard state, the characteristics of the rapid variability are too complex to be successfully described with PROPFLUC. The surface density profile of the hot flow predicted by our model and the lack of quasi-periodic oscillations in the soft and hard states suggest that the spin of the black hole is aligned with the inner accretion disc and therefore probably with the rotational axis of the binary system.

  5. NuSTAR discovery of a luminosity dependent cyclotron line energy in Vela X-1

    Energy Technology Data Exchange (ETDEWEB)

    Fürst, Felix; Grefenstette, Brian W.; Harrison, Fiona; Madsen, Kristin K.; Walton, Dominic J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Pottschmidt, Katja [Center for Space Science and Technology, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Wilms, Jörn [Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr. 7, D-96049 Bamberg (Germany); Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Bachetti, Matteo [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Miller, Jon M. [Department of Astronomy, The University of Michigan, Ann Arbor, MI 48109 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Zhang, William [NASA Goddard Space Flight Center, Astrophysics Science Division, Code 662, Greenbelt, MD 20771 (United States)

    2014-01-10

    We present NuSTAR observations of Vela X-1, a persistent, yet highly variable, neutron star high-mass X-ray binary (HMXB). Two observations were taken at similar orbital phases but separated by nearly a year. They show very different 3-79 keV flux levels as well as strong variability during each observation, covering almost one order of magnitude in flux. These observations allow, for the first time ever, investigations on kilo-second time-scales of how the centroid energies of cyclotron resonant scattering features (CRSFs) depend on flux for a persistent HMXB. We find that the line energy of the harmonic CRSF is correlated with flux, as expected in the sub-critical accretion regime. We argue that Vela X-1 has a very narrow accretion column with a radius of around 0.4 km that sustains a Coulomb interaction dominated shock at the observed luminosities of L {sub x} ∼ 3 × 10{sup 36} erg s{sup –1}. Besides the prominent harmonic line at 55 keV the fundamental line around 25 keV is clearly detected. We find that the strengths of the two CRSFs are anti-correlated, which we explain by photon spawning. This anti-correlation is a possible explanation for the debate about the existence of the fundamental line. The ratio of the line energies is variable with time and deviates significantly from 2.0, also a possible consequence of photon spawning, which changes the shape of the line. During the second observation, Vela X-1 showed a short off-state in which the power-law softened and a cut-off was no longer measurable. It is likely that the source switched to a different accretion regime at these low mass accretion rates, explaining the drastic change in spectral shape.

  6. P2X1 receptors and the endothelium

    Directory of Open Access Journals (Sweden)

    LS Harrington

    2005-03-01

    Full Text Available Adenosine triphosphate (ATP is now established as a principle vaso-active mediator in the vasculature. Its actions on arteries are complex, and are mediated by the P2X and P2Y receptor families. It is generally accepted that ATP induces a bi-phasic response in arteries, inducing contraction via the P2X and P2Y receptors on the smooth muscle cells, and vasodilation via the actions of P2Y receptors located on the endothelium. However, a number of recent studies have placed P2X1 receptors on the endothelium of some arteries. The use of a specific P2X1 receptor ligand, a, b methylene ATP has demonstrated that P2X1 receptors also have a bi-functional role. The actions of ATP on P2X1 receptors is therefore dependant on its location, inducing contraction when located on the smooth muscle cells, and dilation when expressed on the endothelium, comparable to that of P2Y receptors.

  7. Measuring a truncated disk in Aquila X-1

    DEFF Research Database (Denmark)

    King, Ashley L.; Tomsick, John A.; Miller, Jon M.

    2016-01-01

    We present NuSTAR and Swift observations of the neutron star Aquila X-1 during the peak of its 2014 July outburst. The spectrum is soft with strong evidence for a broad Fe Kα line. Modeled with a relativistically broadened reflection model, we find that the inner disk is truncated with an inner r...

  8. The temporal behaviour of Taurus X-1 (the Crab Nebula)

    International Nuclear Information System (INIS)

    Davison, P.J.N.

    1975-01-01

    Copernicus data on Taurus X-1 and the Crab pulsar extending over a 2 1/2-yr period indicate that under normal conditions the source has a flux that is constant to within 2.5 per cent at the 90 per cent confidence level. The pulsed/total flux ratio also shows no significant changes during the same time. (author)

  9. Hard X-ray observation of HER X-1

    Energy Technology Data Exchange (ETDEWEB)

    Ubertini, P.; Bazzano, A.; La Padula, C.; Polcaro, V.F.; Vialetto, G. (Consiglio Nazionale delle Ricerche, Frascati (Italy). Lab. di Astrofisica Spaziale); Manchanda, R.K. (Tata Inst. of Fundamental Research, Bombay (India))

    1981-01-01

    A hard X-rays (15-170 KeV) measurement of the spectrum of Her X-1, during a mid turn-on is presented. The presence of an emission line at about 53 KeV during the mid-on state is confirmed by the present measure.

  10. Hard X-ray observation of HER X-1

    International Nuclear Information System (INIS)

    Ubertini, P.; Bazzano, A.; La Padula, C.; Polcaro, V.F.; Vialetto, G.

    1981-01-01

    A hard X-rays (15-170 KeV) measurement of the spectrum of Her X-1, during a mid turn-on is presented. The presence of an emission line at about 53 KeV during the mid-on state is confirmed by the present measure. (orig.)

  11. Response of the middle atmosphere to Sco X-1

    Science.gov (United States)

    Goldberg, R. A.; Barcus, J. R.; Mitchell, J. D.

    1985-10-01

    On the night of Mar. 9, 1983 (UT) at Punta Lobos Launch Site, Peru (12.5 deg S, 76.8 deg W, magnetic dip -0.7 deg), a sequence of sounding rockets was flown to study the electrical structure of the equatorial middle atmosphere and to evaluate perturbations on this environment induced by the X-ray star Sco X-1. The rocket series was anchored by two Nike Orion payloads (31.032 and 31.033) which were launched at 0327 and 0857 UT, near Sco X-1 star-rise and after it had attained an elevation angle of 70 deg E. An enhanced flux of X-rays was observed on the second Nike Orion flight (31.033). This increase is directly attributed to Sco X-1, both from the spectral properties of the measured X-ray distribution and by spatial information acquired from a spinning X-ray detector during the upleg portion of the 31.033 flight. Simultaneously, a growth in ion conductivity and density was seen to occur in the lower mesosphere between 60 and 80 km on the second flight, specifically in the region of maximum energy deposition by the Sco X-1 X-rays. The results imply the presence of a significant number of ionized heavy constituents within the lower mesosphere, with masses possibly in the submacroscopoic range.

  12. Cygnus X-1: Discovery of variable circular polarization

    International Nuclear Information System (INIS)

    Michalsky, J.J.; Swedlund, J.B.; Stokes, R.A.

    1975-01-01

    HDE 226868, the optical counterpart of Cyg X-1, has been observed for circular polarization during 1974. Observations in five colors suggest that circular polarization results from an interstellar effect. Measurements of the blue polarization reveal circular polarization variations synchronous with the 5)./sub /6 orbital period. The circular polarization variation appears to be similar to the blue intensity variation

  13. Hard X-ray spectrum of Her X-1

    International Nuclear Information System (INIS)

    Ubertini, P.; Bazzano, A.; La Padula, C.D.; Polcaro, V.F.

    1981-01-01

    The results of a balloon borne hard X-ray observation of Her X-1 is presented. The experiment, released from the base of Hyderabad (India) the 19th April 1980, was a collaboration between the Istituto di Astrofisica Spaziale (Italy) and the TIFR (India). The data obtained are compatible with a thermal emission at low energy with a strong emission line overimposed on the continuum around 50-60 keV

  14. Response of the middle atmosphere to Sco X-1

    International Nuclear Information System (INIS)

    Goldberg, R.A.; Barcus, J.R.; Mitchell, J.D.

    1985-01-01

    On the night of 9 March 1983 (UT) at Punta Lobos Launch Site, Peru, a sequence of sounding rockets was flown to study the electrical structure of the equatorial middle atmosphere and to evaluate perturbations on this environment induced by the X-ray star Sco X-1. The rocket series was anchored by two Nike Orion payloads which were launched at 0327 and 0857 UT, near Sco X-1 star-rise and after it had attained an elevation angle of 70 deg E. Each of these payloads carried instrumentation during parachute descent to measure X-ray and electron fluxes, ion density, conductivity and mobility, and in situ electric fields. In addition, several smaller payloads capable of measuring the atmospheric electrical parameters were launched at times interspersed among the large rockets. An enhanced flux of X-rays was observed on the second Nike Orion flight. This increase is directly attributed to Sco X-1, both from the spectral properties of the measured X-ray distribution and by spatial information acquired from a spinning X-ray detector during the upleg portion of the 31.033 flight. Simultaneously, a growth in ion conductivity and density was seen to occur in the lower mesosphere between 60 and 80 km on the second flight. The results are discussed. (author)

  15. Binary Masking & Speech Intelligibility

    DEFF Research Database (Denmark)

    Boldt, Jesper

    The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either experime......The purpose of this thesis is to examine how binary masking can be used to increase intelligibility in situations where hearing impaired listeners have difficulties understanding what is being said. The major part of the experiments carried out in this thesis can be categorized as either...... experiments under ideal conditions or as experiments under more realistic conditions useful for real-life applications such as hearing aids. In the experiments under ideal conditions, the previously defined ideal binary mask is evaluated using hearing impaired listeners, and a novel binary mask -- the target...... binary mask -- is introduced. The target binary mask shows the same substantial increase in intelligibility as the ideal binary mask and is proposed as a new reference for binary masking. In the category of real-life applications, two new methods are proposed: a method for estimation of the ideal binary...

  16. Interacting binary stars

    CERN Document Server

    Sahade, Jorge; Ter Haar, D

    1978-01-01

    Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

  17. The reflection component from Cygnus X-1 in the soft state measured by NuSTAR and Suzaku

    Energy Technology Data Exchange (ETDEWEB)

    Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Nowak, Michael A. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics, Cambridge, MA 02139 (United States); Parker, Michael; Fabian, Andy C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Miller, Jon M.; King, Ashley L. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Harrison, Fiona A.; Forster, Karl; Fürst, Felix; Grefenstette, Brian W.; Madsen, Kristin K. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Bachetti, Matteo; Barret, Didier [Université de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse (France); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Natalucci, Lorenzo [Istituto Nazionale di Astrofisica, INAF-IAPS, via del Fosso del Cavaliere, I-00133 Roma (Italy); Pottschmidt, Katja [CRESST and NASA Goddard Space Flight Center, Astrophysics Science Division, Code 661, Greenbelt, MD 20771 (United States); Ross, Randy R., E-mail: jtomsick@ssl.berkeley.edu [Physics Department, College of the Holy Cross, Worcester, MA 01610 (United States); and others

    2014-01-01

    The black hole binary Cygnus X-1 was observed in late 2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ∼1-300 keV range. The source was in the soft state with a multi-temperature blackbody, power law, and reflection components along with absorption from highly ionized material in the system. The high throughput of NuSTAR allows for a very high quality measurement of the complex iron line region as well as the rest of the reflection component. The iron line is clearly broadened and is well described by a relativistic blurring model, providing an opportunity to constrain the black hole spin. Although the spin constraint depends somewhat on which continuum model is used, we obtain a {sub *} > 0.83 for all models that provide a good description of the spectrum. However, none of our spectral fits give a disk inclination that is consistent with the most recently reported binary values for Cyg X-1. This may indicate that there is a >13° misalignment between the orbital plane and the inner accretion disk (i.e., a warped accretion disk) or that there is missing physics in the spectral models.

  18. The reflection component from Cygnus X-1 in the soft state measured by NuSTAR and Suzaku

    International Nuclear Information System (INIS)

    Tomsick, John A.; Boggs, Steven E.; Craig, William W.; Nowak, Michael A.; Parker, Michael; Fabian, Andy C.; Miller, Jon M.; King, Ashley L.; Harrison, Fiona A.; Forster, Karl; Fürst, Felix; Grefenstette, Brian W.; Madsen, Kristin K.; Bachetti, Matteo; Barret, Didier; Christensen, Finn E.; Hailey, Charles J.; Natalucci, Lorenzo; Pottschmidt, Katja; Ross, Randy R.

    2014-01-01

    The black hole binary Cygnus X-1 was observed in late 2012 with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Suzaku, providing spectral coverage over the ∼1-300 keV range. The source was in the soft state with a multi-temperature blackbody, power law, and reflection components along with absorption from highly ionized material in the system. The high throughput of NuSTAR allows for a very high quality measurement of the complex iron line region as well as the rest of the reflection component. The iron line is clearly broadened and is well described by a relativistic blurring model, providing an opportunity to constrain the black hole spin. Although the spin constraint depends somewhat on which continuum model is used, we obtain a * > 0.83 for all models that provide a good description of the spectrum. However, none of our spectral fits give a disk inclination that is consistent with the most recently reported binary values for Cyg X-1. This may indicate that there is a >13° misalignment between the orbital plane and the inner accretion disk (i.e., a warped accretion disk) or that there is missing physics in the spectral models.

  19. The Si(100)-Sb 2x1 and Ge(100) 2x1 surfaces: A multi-technique study

    International Nuclear Information System (INIS)

    Richter, M.

    1993-08-01

    The electronic and geometric structures of the clean and Sb terminated Si(100)2x1 and Ge(100)-2x1 surfaces have been investigated using a multi-technique approach. Low energy electron diffraction (LEED), scanning tunneling microscopy (STM), surface extended X-ray absorption fine structure (SEXAFS) spectroscopy and angle-integrated core-level photoemission electron spectroscopy (PES) were employed to measure the surface symmetry, defect structure, relevant bond lengths, atomic coordination and electronic structure. By employing a multi-technique approach, it is possible to correlate changes in the geometric structure to specific features of the core-level lineshape of the substrate. This allows for the assignment of components of the core-level lineshape to be assigned to specific surface and near-surface atoms

  20. Short term variation of Cyg X-1 in the hard x-ray region

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Kosei [Tokyo Univ. (Japan). Inst. of Space and Aeronautical Science

    1978-08-01

    Cyg X-1 is a peculiar celestial body considered to be a close binary system of a black hole and a blue super-giant star. It is presently known that the time fluctuation of Cyg X-1 is considerably complex, ranging from seconds to days or months. Of these variation, attention has been paid to the short time variation in relation to the black hole theory. Observations of fluctuations in the order of second have been limited to soft X-ray (20 keV or more) so far, because great technical difficulties are involved due to the low intensity of hard X-ray. The present investigation is based on the fluctuations in the order of second in hard X-ray, and was conducted by employing an unprecedented large area X-ray telescope. The text describes on the brief history of the short time fluctuation, explains the experimental plan, X-ray detecting system, flight of a balloon and the analyses and discussions of fluctuation factor by variation function method, and gives the analysis data and conclusion. The observations resulted in the fact that the fluctuations in the order of second were small at 20 to 30 keV, but become large when energy is higher or lower than this value. The most natural explanation available for this result may be that it is essentially spectrum fluctuation, being inverse correlation in higher and lower energies. Physical meaning of such spectrum fluctuation is considered in connection with precipitating disk model around a black hole.

  1. The smooth cyclotron line in Her X-1 as seen with nuclear spectroscopic telescope array

    Energy Technology Data Exchange (ETDEWEB)

    Fürst, Felix; Grefenstette, Brian W.; Bellm, Eric C.; Harrison, Fiona; Madsen, Kristin K.; Walton, Dominic J. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Staubert, Rüdiger; Klochkov, Dmitry [Institut für Astronomie und Astrophysik, Universität Tübingen (IAAT), D-72076 Tübingen (Germany); Tomsick, John A.; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Bachetti, Matteo; Barret, Didier [Université de Toulouse, UPS-OMP, IRAP, F-31028 Toulouse (France); Chenevez, Jerome; Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Pottschmidt, Katja [CRESST, UMBC, and NASA GSFC, Code 661, Greenbelt, MD 20771 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Wilms, Jörn [Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr. 7, D-96049 Bamberg (Germany); William Zhang [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-12-10

    Her X-1, one of the brightest and best studied X-ray binaries, shows a cyclotron resonant scattering feature (CRSF) near 37 keV. This makes it an ideal target for a detailed study with the Nuclear Spectroscopic Telescope Array (NuSTAR), taking advantage of its excellent hard X-ray spectral resolution. We observed Her X-1 three times, coordinated with Suzaku, during one of the high flux intervals of its 35 day superorbital period. This paper focuses on the shape and evolution of the hard X-ray spectrum. The broadband spectra can be fitted with a power law with a high-energy cutoff, an iron line, and a CRSF. We find that the CRSF has a very smooth and symmetric shape in all observations and at all pulse phases. We compare the residuals of a line with a Gaussian optical-depth profile to a Lorentzian optical-depth profile and find no significant differences, strongly constraining the very smooth shape of the line. Even though the line energy changes dramatically with pulse phase, we find that its smooth shape does not. Additionally, our data show that the continuum only changes marginally between the three observations. These changes can be explained with varying amounts of Thomson scattering in the hot corona of the accretion disk. The average, luminosity-corrected CRSF energy is lower than in past observations and follows a secular decline. The excellent data quality of NuSTAR provides the best constraint on the CRSF energy to date.

  2. Short term variation of Cyg X-1 in the hard x-ray region

    International Nuclear Information System (INIS)

    Doi, Kosei

    1978-01-01

    Cyg X-1 is a peculiar celestial body considered to be a close binary system of a black hole and a blue super-giant star. It is presently known that the time fluctuation of Cyg X-1 is considerably complex, ranging from seconds to days or months. Of these variation, attention has been paid to the short time variation in relation to the black hole theory. Observations of fluctuations in the order of second have been limited to soft X-ray (20 keV or more) so far, because great technical difficulties are involved due to the low intensity of hard X-ray. The present investigation is based on the fluctuations in the order of second in hard X-ray, and was conducted by employing an unprecedented large area X-ray telescope. The text describes on the brief history of the short time fluctuation, explains the experimental plan, X-ray detecting system, flight of a balloon and the analyses and discussions of fluctuation factor by variation function method, and gives the analysis data and conclusion. The observations resulted in the fact that the fluctuations in the order of second were small at 20 to 30 keV, but become large when energy is higher or lower than this value. The most natural explanation available for this result may be that it is essentially spectrum fluctuation, being inverse correlation in higher and lower energies. Physical meaning of such spectrum fluctuation is considered in connection with precipitating disk model around a black hole. (Wakatsuki, Y.)

  3. A detection of HER-X 1 at PeV energies, with anomalous muon number

    International Nuclear Information System (INIS)

    Nagle, D.E.

    1990-01-01

    The CYGNUS collaboration is operating a ground-based array of scintillation detectors to detect-extensive air showers. This paper reports that the objective is to detect compact sources of Ultra High Energy (PeV) gamma radiation. At the present time the array consists of 106 scintillation detectors of ∼10 4 m 2 . It is supplemented by a tracking detector of muons, shielded by about 6 feet of steel: its purpose is to compare the number of muons from purported gamma-ray primaries with the number from ordinary cosmic-ray primaries. Last year we reported 2 an unusual episode of emission from the direction of the binary source Hercules X-1, with the following features: on 24 July 1986 an excess event rate in the direction of Her X-1 was detected. The pulsar period observed, namely T = (1.23568s ± 0.0003s), is blue-shifted by about 0.16% from the contemporary X-ray period. The average number of muons detected in these events is not less than the number for ordinary cosmic ray events as seen in our detector. At Tev energies, two stations operating air-Cherenkov telescopes, namely Mt. Hopkins and Haleakala, had reported periods nearly identical to the authors': Lamb et al., T = (1.23579 ± 0.0002), and Resvanis et al., T = (1.23593 ± 0.0002). Recently the Haleakala group have added another detection, on May 23, 1987: T = 23598s. Another report comes from the Tata Institute, Bombay, which operates the air-shower array at Ooty

  4. Mining frequent binary expressions

    NARCIS (Netherlands)

    Calders, T.; Paredaens, J.; Kambayashi, Y.; Mohania, M.K.; Tjoa, A.M.

    2000-01-01

    In data mining, searching for frequent patterns is a common basic operation. It forms the basis of many interesting decision support processes. In this paper we present a new type of patterns, binary expressions. Based on the properties of a specified binary test, such as reflexivity, transitivity

  5. Comprehensive spectral analysis of Cyg X-1 using RXTE data

    International Nuclear Information System (INIS)

    Shahid, Rizwan; Jaaffrey, S. N. A.; Misra, Ranjeev

    2012-01-01

    We analyze a large number (> 500) of pointed Rossi X-Ray Timing Explorer (RXTE) observations of Cyg X-1 and model the spectrum of each one. A subset of the observations for which there is a simultaneous reliable measure of the hardness ratio by the All Sky Monitor shows that the sample covers nearly all the spectral shapes of Cyg X-1. Each observation is fitted with a generic empirical model consisting of a disk black body spectrum, a Comptonized component whose input photon shape is the same as the disk emission, a Gaussian to represent the iron line and a reflection feature. The relative strength, width of the iron line and the reflection parameter are in general correlated with the high energy photon spectral index Γ. This is broadly consistent with a geometry where for the hard state (low Γ ∼ 1.7) there is a hot inner Comptonizing region surrounded by a truncated cold disk. The inner edge of the disk moves inwards as the source becomes softer till finally in the soft state (high Γ > 2.2) the disk fills the inner region and active regions above the disk produce the Comptonized component. However, the reflection parameter shows non-monotonic behavior near the transition region (Γ ∼ 2), which suggests a more complex geometry or physical state of the reflector. In addition, the inner disk temperature, during the hard state, is on average higher than in the soft one, albeit with large scatter. These inconsistencies could be due to limitations in the data and the empirical model used to fit them. The flux of each spectral component is well correlated with Γ, which shows that unlike some other black hole systems, Cyg X-1 does not show any hysteresis behavior. In the soft state, the flux of the Comptonized component is always similar to the disk one, which confirms that the ultra-soft state (seen in other brighter black hole systems) is not exhibited by Cyg X-1. The rapid variation of the Compton amplification factor with Γ naturally explains the absence of

  6. Long term variability of HDE 226868 = Cygnus X-1

    International Nuclear Information System (INIS)

    Liller, W.

    1976-01-01

    Investigation of blue-sensitive photographs of HDE 226868 = Cygnus X-1 reveal no (+-0.06 mag) long-term changes in brightness since the beginning of the century nor any abrupt intensity changes similar to what has been observed at x-ray and radio frequencies. From the double sinusoidal fluctuation with 5.6 day period, an attempt is made to derive a more precise value for the orbital period, but problems are encountered and discussed. There exists evidence that the amplitude of the orbital fluctuations is increasing slowly with time

  7. Discovery of a 115 Day Orbital Period in the Ultraluminous X-ray Source NGC 5408 X-1

    Science.gov (United States)

    Strohmayer, Tod E.

    2009-01-01

    We report the detection of a 115 day periodicity in SWIFT/XRT monitoring data from the ultraluminous X-ray source (ULX) NGC 5408 X-1. Our o ngoing campaign samples its X-ray flux approximately twice weekly and has now achieved a temporal baseline of ti 485 days. Periodogram ana lysis reveals a significant periodicity with a period of 115.5 +/- 4 days. The modulation is detected with a significance of 3.2 x 10(exp -4) . The fractional modulation amplitude decreases with increasing e nergy, ranging from 0.13 +/- 0.02 above 1 keV to 0.24 +/- 0.02 below 1 keV. The shape of the profile evolves as well, becoming less sharply peaked at higher energies. The periodogram analysis is consistent wi th a periodic process, however, continued monitoring is required to c onfirm the coherent nature of the modulation. Spectral analysis indic ates that NGC 5408 X-1 can reach 0.3 - 10 keV luminosities of approxi mately 2 x 10 40 ergs/s . We suggest that, like the 62 day period of the ULX in M82 (X41.4-1-60), the periodicity detected in NGC 5408 X-1 represents the orbital period of the black hole binary containing the ULX. If this is true then the secondary can only be a giant or super giant star.

  8. The high-energy pulsed X-ray spectrum of Hercules X-1 as observed with OSO 8

    Science.gov (United States)

    Maurer, G. S.; Dennis, B. R.; Coe, M. J.; Crannell, C. J.; Dolan, J. F.; Frost, K. J.; Orwig, L. E.; Cutler, E. P.

    1979-01-01

    Hercules X-1 was observed from August 30 to September 10, 1977, by using the high-energy X-ray scintillation spectrometer on board the OSO 8 satellite. The observation, during which the source was monitored continually for nearly an entire ON-state, covered the energy range from 16 to 280 keV. Pulsed-flux measurements as a function of binary orbit and binary phase are presented for energies between 16 and 98 keV. The pulsed flux between 16 and 33 keV exhibited a sharp decrease following the fourth binary orbit and was consistent with zero pulsed flux thereafter. Only weak evidence was found for temporal variation in the pulsed flux between 33 and 98 keV. The pulsed spectrum has been fitted with a power law, a thermal spectrum without features, and a thermal spectrum with a superposed Gaussian centered at 55 keV. The latter fit has the smallest value of chi-square per degree of freedom, and the resulting integrated line intensity is approximately 0.0015 photon/sec per sq cm for a width of 3.1 (+9.1, -2.6) keV. This result, while of low statistical significance, agrees with the value observed by Truemper (1978) during the same ON-state.

  9. Broad-Band Spectroscopy of Hercules X-1 with Suzaku

    Science.gov (United States)

    Asami, Fumi; Enoto, Teruaki; Iwakiri, Wataru; Yamada, Shin'ya; Tamagawa, Toru; Mihara, Tatehiro; Nagase, Fumiaki

    2014-01-01

    Hercules X-1 was observed with Suzaku in the main-on state from 2005 to 2010. The 0.4- 100 keV wide-band spectra obtained in four observations showed a broad hump around 4-9 keV in addition to narrow Fe lines at 6.4 and 6.7 keV. The hump was seen in all the four observations regardless of the selection of the continuum models. Thus it is considered a stable and intrinsic spectral feature in Her X-1. The broad hump lacked a sharp structure like an absorption edge. Thus it was represented by two different spectral models: an ionized partial covering or an additional broad line at 6.5 keV. The former required a persistently existing ionized absorber, whose origin was unclear. In the latter case, the Gaussian fitting of the 6.5-keV line needs a large width of sigma = 1.0-1.5 keV and a large equivalent width of 400-900 eV. If the broad line originates from Fe fluorescence of accreting matter, its large width may be explained by the Doppler broadening in the accretion flow. However, the large equivalent width may be inconsistent with a simple accretion geometry.

  10. On the parameters of the system Cyg X-1

    International Nuclear Information System (INIS)

    Sokolov, V.V.

    1987-01-01

    Estimations are given of the mass of the supergiant HDE 226868 in the system Cyg X-1 which are made on the basis of interpretation of spectroscopic observations by means of the model-atmosphere method. The importance is pointed out of accounting for deviations from LTE in calculations of equivalent widths and profiles of hydrogen lines by which the acceleration of gravity force on the surface of the optical star of system is determined. Supergiant mass determined in that way turns out to be M*=(16±3)M sun . Provided the zone of formation of the emission He II λ4686 A must be localized near the supergiant surface, the least value of inclination of system orbit plane is estimated: i>or approx. 35 deg. The possibility is pointed out of variability of equivalent widths of He II emission λ4686 A, which is connected with eclipse of the ''spot'', i.e. of area of localization of this emission. It is noted that for large angles (i>or approx. 35 deg) of orbit inclinaion, the mass of the degenerate star in the system Cyg X-1 does not exceed 10 M sun

  11. RAPID SPECTRAL CHANGES OF CYGNUS X-1 IN THE LOW/HARD STATE WITH SUZAKU

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, S.; Makishima, K. [Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Negoro, H. [Department of Physics, College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Torii, S.; Noda, H. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Mineshige, S. [Department of Astronomy, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-04-20

    Rapid spectral changes in the hard X-ray on a timescale down to {approx}0.1 s are studied by applying a ''shot analysis'' technique to the Suzaku observations of the black hole binary Cygnus X-1, performed on 2008 April 18 during the low/hard state. We successfully obtained the shot profiles, covering 10-200 keV with the Suzaku HXD-PIN and HXD-GSO detector. It is notable that the 100-200 keV shot profile is acquired for the first time owing to the HXD-GSO detector. The intensity changes in a time-symmetric way, though the hardness changes in a time-asymmetric way. When the shot-phase-resolved spectra are quantified with the Compton model, the Compton y-parameter and the electron temperature are found to decrease gradually through the rising phase of the shot, while the optical depth appears to increase. All the parameters return to their time-averaged values immediately within 0.1 s past the shot peak. We have not only confirmed this feature previously found in energies below {approx}60 keV, but also found that the spectral change is more prominent in energies above {approx}100 keV, implying the existence of some instant mechanism for direct entropy production. We discuss possible interpretations of the rapid spectral changes in the hard X-ray band.

  12. The WA105-3x1x1 m3 dual phase LAr-TPC demonstrator

    CERN Document Server

    Murphy, Sebastien

    2016-11-15

    The dual phase Liquid Argon Time Projection Chamber (LAr TPC) is the state-of-art technology for neutrino detection thanks to its superb 3D tracking and calorimetry performance. Its main feature is the charge amplification in gas argon which provides excellent signal-to-noise ratio. Electrons produced in the liquid argon are extracted in the gas phase. Here, a readout plane based on Large Electron Multiplier detectors provides amplification of the charges before its collection onto an anode with strip readout. The charge amplification enables constructing fully homoge- nous giant LAr-TPCs with tuneable gain, excellent charge imaging performance and increased sensitivity to low energy events. Following a staged approach the WA105 collaboration is con- structing a dual phase LAr-TPC with an active volume of 3x1x1m3 that will soon be tested with cosmic rays. Its construction and operation aims to test scalable solutions for the crucial aspects of this technology: ultra high argon purity in non-evacuable tank, la...

  13. Search for very high-energy gamma-ray emission from the microquasar Cygnus X-1 with the MAGIC telescopes

    Science.gov (United States)

    Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Bhattacharyya, W.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; de Oña Wilhelmi, E.; di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.; MAGIC Collaboration; Bosch-Ramon, V.; Pooley, G. G.; Trushkin, S. A.; Zanin, R.

    2017-12-01

    The microquasar Cygnus X-1 displays the two typical soft and hard X-ray states of a black hole transient. During the latter, Cygnus X-1 shows a one-sided relativistic radio-jet. Recent detection of the system in the high energy (HE; E ≳ 60 MeV) gamma-ray range with Fermi-LAT associates this emission with the outflow. Former MAGIC observations revealed a hint of flaring activity in the very high-energy (VHE; E ≳ 100 GeV) regime during this X-ray state. We analyse ∼97 h of Cygnus X-1 data taken with the MAGIC telescopes between July 2007 and October 2014. To shed light on the correlation between hard X-ray and VHE gamma rays as previously suggested, we study each main X-ray state separately. We perform an orbital phase-folded analysis to look for variability in the VHE band. Additionally, to place this variability behaviour in a multiwavelength context, we compare our results with Fermi-LAT, AGILE, Swift-BAT, MAXI, RXTE-ASM, AMI and RATAN-600 data. We do not detect Cygnus X-1 in the VHE regime. We establish upper limits for each X-ray state, assuming a power-law distribution with photon index Γ = 3.2. For steady emission in the hard and soft X-ray states, we set integral upper limits at 95 per cent confidence level for energies above 200 GeV at 2.6 × 10-12 photons cm-2 s-1 and 1.0 × 10-11 photons cm-2 s-1, respectively. We rule out steady VHE gamma-ray emission above this energy range, at the level of the MAGIC sensitivity, originating in the interaction between the relativistic jet and the surrounding medium, while the emission above this flux level produced inside the binary still remains a valid possibility.

  14. High resolution measurements of Cyg X-1 from rockets

    International Nuclear Information System (INIS)

    Rothschild, R.E.; Boldt, E.A.; Holt, S.S.; Serlemitsos, P.J.

    1976-01-01

    Cyg X-1 was observed on two occasions (Oct. 4, 1973 and Oct. 3, 1974) by the Goddard x-ray rocket payload. This payload consisted of two gas proportional counters (xenon--methane with 710 cm 2 and argon--methane with 610 cm 2 ) using the same 128 channel pulse height analyzer and having 320 μs temporal resolution on the 1973 flight and 160 μs resolution on the 1974 flight. During both flights bursts of 1 ms duration were observed with very high statistical certainty. To date all 13 of these bursts have been analyzed for spectral and temporal character, and the results of this analysis are presented. The spectra of overall x-ray emission from both flights are also presented. In a source known for its variability it is remarkable that the spectra taken one year apart are virtually identical

  15. The Extreme Spin of the Black Hole Cygnus X-1

    Science.gov (United States)

    Gou, Lijun; McClintock, Jeffrey E.; Reid, Mark J.; Orosz, Jerome A.; Steiner, James F.; Narayan, Ramesh; Xiang, Jingen; Remillard, Ronald A.; Arnaud, Keith A.; Davis, Shane W.

    2011-01-01

    Remarkably, an astronomical black hole is completely described by the two numbers that specify its mass and its spin. Knowledge of spin is crucial for understanding how, for example, black holes produce relativistic jets. Recently, it has become possible to measure the spins of black holes by focusing on the very inner region of an accreting disk of hot gas orbiting the black hole. According to General Relativity (GR), this disk is truncated at an inner radius 1 that depends only on the mass and spin of the black hole. We measure the radius of the inner edge of this disk by fitting its continuum X-ray spectrum to a fully relativistic model. Using our measurement of this radius, we deduce that the spin of Cygnus X-1 exceeds 97% of the maximum value allowed by GR.

  16. Measuring a Truncated Disk in Aquila X-1

    Science.gov (United States)

    King, Ashley L.; Tomsick, John A.; Miller, Jon M.; Chenevez, Jerome; Barret, Didier; Boggs, Steven E.; Chakrabarty, Deepto; Christensen, Finn E.; Craig, William W.; Feurst, Felix; hide

    2016-01-01

    We present NuSTAR and Swift observations of the neutron star Aquila X-1 during the peak of its 2014 July outburst. The spectrum is soft with strong evidence for a broad Fe K(alpha) line. Modeled with a relativistically broadened reflection model, we find that the inner disk is truncated with an inner radius of 15 +/- 3RG. The disk is likely truncated by either the boundary layer and/or a magnetic field. Associating the truncated inner disk with pressure from a magnetic field gives an upper limit of B < 5+/- 2x10(exp 8) G. Although the radius is truncated far from the stellar surface, material is still reaching the neutron star surface as evidenced by the X-ray burst present in the NuSTAR observation.

  17. Pion production In The Inner Disk Around Cygnus X-1

    International Nuclear Information System (INIS)

    Meirelles Filho, C.; Miyake, H.; Timoteo, V.S.; Lima, C.L.

    2004-01-01

    Neutron production via 4He breakup and p(p, nπ+)p is considered in the innermost region of an accretion disk surrounding a Kerr Black Hole. Close to the horizon, the contribution from p(p, nπ+)p to the neutron production is comparable to that from the breakup. It is shown that the viscosity generated by the collisions of the accreting matter with the neutrons may drive stationary accretion, for accretion rates below a critical value. In this case, solution to the disk equations is double-valued and for both solutions protons overnumber the pairs. We suggest that these solutions may mimic the states of high and low luminosity observed in Cygnus X-1

  18. Ultra-high energy signals from Hercules X-1

    International Nuclear Information System (INIS)

    Haines, T.J.; Alexandreas, D.E.; Allen, R.C.

    1988-01-01

    The expectation that high-energy neutrinos are emitted from astrophysical objects depends strongly on the observation of those objects in gamma-rays, especially at TeV and PeV energies. A search for bursts of gamma-ray events from Hercules X-1 at energies above 50 TeV yielded two significant bursts, both occurring on UT 24 July 1986. The events were pulsed with a period of 1.23568 s, significantly different from estimates of the pulsar period at that time. The probability that the signal is a random background fluctuation is about 2 /times/ 10/sup /minus/5/, not including the fact that there were two other independent observations of the source at nearly the same time. The muon content of the burst events is anomalous when compared with expectations of gamma-ray showers, perhaps signalling the onset of new physics at these energies. 9 refs., 4 figs., 1 tab

  19. Close binary stars

    International Nuclear Information System (INIS)

    Larsson-Leander, G.

    1979-01-01

    Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)

  20. Binary and ternary systems

    International Nuclear Information System (INIS)

    Petrov, D.A.

    1986-01-01

    Conditions for thermodynamical equilibrium in binary and ternary systems are considered. Main types of binary and ternary system phase diagrams are sequently constructed on the basis of general regularities on the character of transition from one equilibria to others. New statements on equilibrium line direction in the diagram triple points and their isothermal cross sections are developed. New represenations on equilibria in case of monovariant curve minimum and maximum on three-phase equilibrium formation in ternary system are introduced

  1. Planet formation in Binaries

    OpenAIRE

    Thebault, Ph.; Haghighipour, N.

    2014-01-01

    Spurred by the discovery of numerous exoplanets in multiple systems, binaries have become in recent years one of the main topics in planet formation research. Numerous studies have investigated to what extent the presence of a stellar companion can affect the planet formation process. Such studies have implications that can reach beyond the sole context of binaries, as they allow to test certain aspects of the planet formation scenario by submitting them to extreme environments. We review her...

  2. Black holes and neutron stars: evolution of binary systems

    International Nuclear Information System (INIS)

    Kraft, R.P.

    1975-01-01

    Evidence for the existence of neutron stars and black holes in binary systems has been reviewed, and the following summarizes the current situation: (1) No statistically significant case has been made for the proposition that black holes and/or neutron stars contribute to the population of unseen companions of ordinary spectroscopic binaries; (2) Plausible evolutionary scenarios can be advanced that place compact X-ray sources into context as descendants of several common types of mass-exchange binaries. The collapse object may be a black hole, a neutron star, or a white dwarf, depending mostly on the mass of the original primary; (3) The rotating neutron star model for the pulsating X-ray sources Her X-1 and Cen X-3 is the simplest interpretation of these objects, but the idea that the pulsations result from the non-radial oscillations of a white dwarf cannot be altogether dismissed. The latter is particularly attractive in the case of Her X-1 because the total mass of the system is small; (4) The black hole picture for Cyg X-1 represents the simplest model that can presently be put forward to explain the observations. This does not insure its correctness, however. The picture depends on a long chain of inferences, some of which are by no means unassailable. (Auth.)

  3. Accretion-induced spin-wandering effects on the neutron star in Scorpius X-1: Implications for continuous gravitational wave searches

    Science.gov (United States)

    Mukherjee, Arunava; Messenger, Chris; Riles, Keith

    2018-02-01

    The LIGO's discovery of binary black hole mergers has opened up a new era of transient gravitational wave astronomy. The potential detection of gravitational radiation from another class of astronomical objects, rapidly spinning nonaxisymmetric neutron stars, would constitute a new area of gravitational wave astronomy. Scorpius X-1 (Sco X-1) is one of the most promising sources of continuous gravitational radiation to be detected with present-generation ground-based gravitational wave detectors, such as Advanced LIGO and Advanced Virgo. As the sensitivity of these detectors improve in the coming years, so will power of the search algorithms being used to find gravitational wave signals. Those searches will still require integration over nearly year long observational spans to detect the incredibly weak signals from rotating neutron stars. For low mass X-ray binaries such as Sco X-1 this difficult task is compounded by neutron star "spin wandering" caused by stochastic accretion fluctuations. In this paper, we analyze X-ray data from the R X T E satellite to infer the fluctuating torque on the neutron star in Sco X-1. We then perform a large-scale simulation to quantify the statistical properties of spin-wandering effects on the gravitational wave signal frequency and phase evolution. We find that there are a broad range of expected maximum levels of frequency wandering corresponding to maximum drifts of between 0.3 - 50 μ Hz /sec over a year at 99% confidence. These results can be cast in terms of the maximum allowed length of a coherent signal model neglecting spin-wandering effects as ranging between 5-80 days. This study is designed to guide the development and evaluation of Sco X-1 search algorithms.

  4. Synchrotron and Coulomb Boiler in Cygnus X-1

    International Nuclear Information System (INIS)

    Malzac, Julien; Belmont, Renaud

    2009-01-01

    We use a new code to simulate the radiation and kinetic processes in the X-ray emitting region around accreting black holes and constrain the magnetic field and temperature of the hot protons in the corona of Cygnus X-1. In the hard state we find a magnetic field below equipartition with radiation, suggesting that the corona is not powered through magnetic field dissipation (as assumed in most accretion disc corona models). On the other hand, our results also point toward proton temperatures that are substantially lower than typical temperatures of the ADAF models. Finally, we show that in both spectral states Comptonising plasma could be powered essentially through power-law acceleration of non-thermal electrons, which are then partly thermalised by the synchrotron and Coulomb boiler. This suggests that, contrary to current beliefs, the corona of the HSS and that of the LHS could be of very similar nature. The differences between the LHS and HSS coronal spectra would then be predominantly caused by the strong disc soft cooling emission which is present in the HSS and absent in the LHS.

  5. Optical photometry of Cygnus X-1: 1972-1976

    International Nuclear Information System (INIS)

    Walker, E.N.; Quintanilla, A.R.

    1978-01-01

    The blue (Johnson B) magnitude of HDE 226868, the optical counterpart of Cygnus X-1, has been measured on 349 nights between 1972 April and 1976 December. The best-fit period to these data is 5.6015 +- 0.0006 days and the light-curve obtained by folding these data with this period shows features with duration < 0.1 P in addition to the well-established double maxima and minima. It is found that the mean brightness of the star changes by 0.02 mag on a timescale of approximately 150 day and that the extremes of this brightness range are associated with two forms of the light-curve which in combination yield much of the detailed structure of the five-year mean curve. The observations show that there was no change much greater than 0.001 mag in either the 5.6 or 150-day light-curves associated with the X-ray high states. However, a unique form of the 5.6-day light-curve did occur just at the start of the 1975 November X-ray high state. There is some evidence for an overall brightness change during the five years of approximately 0.01 mag. (author)

  6. Protic ionic liquids based on the dimeric and oligomeric anions: [(AcO)xH(x-1)]-.

    Science.gov (United States)

    Johansson, K M; Izgorodina, E I; Forsyth, M; MacFarlane, D R; Seddon, K R

    2008-05-28

    We describe a fluidity and conductivity study as a function of composition in N-methylpyrrolidine-acetic acid mixtures. The simple 1 : 1 acid-base mixture appears to form an ionic liquid, but its degree of ionicity is quite low and such liquids are better thought of as poorly dissociated mixtures of acid and base. The composition consisting of 3 moles acetic acid and 1 mole N-methylpyrrolidine is shown to form the highest ionicity mixture in this binary due to the presence of oligomeric anionic species [(AcO)(x)H(x-1)](-) stabilised by hydrogen bonds. These oligomeric species, being weaker bases than the acetate anion, shift the proton transfer equilibrium towards formation of ionic species, thus generating a higher degree of ionicity than is present at the 1 : 1 composition. A Walden plot analysis, thermogravimetric behaviour and proton NMR data, as well as ab initio calculations of the oligomeric species, all support this conclusion.

  7. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  8. Modelling binary data

    CERN Document Server

    Collett, David

    2002-01-01

    INTRODUCTION Some Examples The Scope of this Book Use of Statistical Software STATISTICAL INFERENCE FOR BINARY DATA The Binomial Distribution Inference about the Success Probability Comparison of Two Proportions Comparison of Two or More Proportions MODELS FOR BINARY AND BINOMIAL DATA Statistical Modelling Linear Models Methods of Estimation Fitting Linear Models to Binomial Data Models for Binomial Response Data The Linear Logistic Model Fitting the Linear Logistic Model to Binomial Data Goodness of Fit of a Linear Logistic Model Comparing Linear Logistic Models Linear Trend in Proportions Comparing Stimulus-Response Relationships Non-Convergence and Overfitting Some other Goodness of Fit Statistics Strategy for Model Selection Predicting a Binary Response Probability BIOASSAY AND SOME OTHER APPLICATIONS The Tolerance Distribution Estimating an Effective Dose Relative Potency Natural Response Non-Linear Logistic Regression Models Applications of the Complementary Log-Log Model MODEL CHECKING Definition of Re...

  9. Evolution of dwarf binaries

    International Nuclear Information System (INIS)

    Tutukov, A.V.; Fedorova, A.V.; Yungel'son, L.R.

    1982-01-01

    The conditions of mass exchange in close binary systems with masses of components less or equal to one solar mass have been analysed for the case, when the system radiates gravitational waves. It has been shown that the mass exchange rate depends in a certain way on the mass ratio of components and on the mass of component that fills its inner critical lobe. The comparison of observed periods, masses of contact components, and mass exchange rates of observed cataclysmic binaries have led to the conclusion that the evolution of close binaries WZ Sge, OY Car, Z Cha, TT Ari, 2A 0311-227, and G 61-29 may be driven by the emission of gravitational waves [ru

  10. Binary catalogue of exoplanets

    Science.gov (United States)

    Schwarz, Richard; Bazso, Akos; Zechner, Renate; Funk, Barbara

    2016-02-01

    Since 1995 there is a database which list most of the known exoplanets (The Extrasolar Planets Encyclopaedia at http://exoplanet.eu/). With the growing number of detected exoplanets in binary and multiple star systems it became more important to mark and to separate them into a new database, which is not available in the Extrasolar Planets Encyclopaedia. Therefore we established an online database (which can be found at: http://www.univie.ac.at/adg/schwarz/multiple.html) for all known exoplanets in binary star systems and in addition for multiple star systems, which will be updated regularly and linked to the Extrasolar Planets Encyclopaedia. The binary catalogue of exoplanets is available online as data file and can be used for statistical purposes. Our database is divided into two parts: the data of the stars and the planets, given in a separate list. We describe also the different parameters of the exoplanetary systems and present some applications.

  11. Binary and Millisecond Pulsars.

    Science.gov (United States)

    Lorimer, Duncan R

    2008-01-01

    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5 M ⊙ , a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric ( e = 0.44) orbit around an unevolved companion. Supplementary material is available for this article at 10.12942/lrr-2008-8.

  12. Binary and Millisecond Pulsars

    Directory of Open Access Journals (Sweden)

    Lorimer Duncan R.

    2008-11-01

    Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M_⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44 orbit around an unevolved companion.

  13. Dissipative binary collisions

    International Nuclear Information System (INIS)

    Aboufirassi, M; Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Meslin, C.; Metivier, V.; Nakagawa, T.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Wieloch, A.; Yuasa-Nakagawa, K.

    1998-01-01

    The binary character of the heavy ion collisions at intermediate energies in the exit channel has been observed under 30 MeV/n in medium and heavy systems. Measurements in light systems at energies approaching ∼ 100 MeV/nucleon as well as in very heavy systems have allowed to extend considerably the investigations of this binary process. Thus, the study of the Pb + Au system showed that the complete charge events indicated two distinct sources: the quasi-projectile and the quasi-target. The characteristics of these two sources are rather well reproduced by a trajectory computation which takes into account the Coulomb and nuclear forces and the friction appearing from the projectile-target interaction. The Wilczynski diagram is used to probe the correlation between the kinetic energy quenching and the deflecting angle. In case of the system Pb + Au at 29 MeV/nucleon the diagram indicate dissipative binary collisions typical for low energies. This binary aspect was also detected in the systems Xe + Ag at 44 MeV/nucleon, 36 Ar + 27 Al and 64 Zn + nat Ti. Thus, it was possible to reconstruct the quasi-projectile and to study its mass and excitation energy evolution as a function of the impact parameter. The dissipative binary collisions represent for the systems and energies under considerations the main contribution to the cross section. This does not implies that there are not other processes; particularly, the more or less complete fusion is also observed but with a low cross section which decreases with the increase of bombardment energy. More exclusive measurements with the INDRA detector on quasi-symmetric systems as Ar + KCl and Xe + Sn seem to confirm the importance of the binary collisions. The two source reconstruction of the Xe + Sn data at 50 MeV/nucleon reproduces the same behaviour as that observed in the system Pb + Au at 29 MeV/nucleon

  14. Short-term variability of Cyg X-1

    International Nuclear Information System (INIS)

    Oda, M.; Doi, K.; Ogawara, Y.

    1976-01-01

    The short-term X-ray variability distinguishes Cyg X-1, which is the most likely candidate for a black hole, from other X-ray sources. The present status of our knowledge on this short-term variation, mainly from the UHURU, the MIT and the GSFC observations, is reviewed. The nature of impulsive variations which compose the time variation exceeding the statistical fluctuation is discussed. There are indications that the energy spectrum of large pulses is harder than the average spectrum, or that the large pulses are the characteristics of the hard component of the spectrum if it is composed of two, soft and hard, components. Features of the variations may be partly simulated by the superposition of random shot-noise pulses with a fraction of a second duration. However, the autocorrelation analysis and the dynamic spectrum analysis indicate that the correlation lasts for several seconds and in the variation are buried some regularities which exhibit power concentrations in several frequency bands; 0.2-0.3, 0.4-0.5, 0.8, 1.2-1.5 Hz. There are several possible interpretations of these results in terms of; e.g. (a) a mixture of shot-noise pulses with two or more constant durations, (b) the shape of the basic shot-noise pulse, (c) bunching of the pulses, (d) superposition of wave-packets or temporal oscillations. But we have not yet reached any definite understandings in the nature of the variabilities. The substructure of the fluctuations on a time scale of milliseconds suggested by two investigations is also discussed. (Auth.)

  15. Short-term variability of CYG X-1

    International Nuclear Information System (INIS)

    Oda, M.; Doi, K.; Ogawara, Y.; Takagishi, K.; Wada, M.

    1975-01-01

    The short-term X-ray variability distinguishes Cyg X-1, which is the most likely candidate of the black hole, from other X-ray sources. Present status of our knowledge on this short-term variation mainly from the Uhuru, the MIT and the GSFC observations is reviewed. The nature of impulsive variations which compose the time variation exceeding the statistical fluctuation is discussed. There are indications that the energy spectrum of large pulses is harder than the average spectrum or the large pulses are the characteristics of the hard component of the spectrum if it is composed of two, soft and hard, components. Features of the variations may be partly simulated by the superposition of random short-noise pulses with a fraction of a second duration. However, the autocorrelation analysis and the dynamic spectrum analysis indicate that the correlation lasts for several seconds and in the variation buried are some regularities which exhibit power concentrations in several frequency bands; 0.2 -- 0.3, 0.4 -- 0.5, 0.8, 1.2 -- 1.5 Hz. There are several possible interpretation of these results in terms of: e.g. a) a mixture of short-noise pulses with two or more constant durations, b) the shape of the basic shot-noise pulse, c) bunching of the pulses, d) superposition of wave-packets or temporal oscillations. But we have not yet reached any definite understandings in the nature of the variabilities. The sub-structure of the fluctuations on a time scale of milli-second suggested by two investigations is also discussed. (auth.)

  16. High-energy gamma-rays from Cyg X-1

    Science.gov (United States)

    Zdziarski, Andrzej A.; Malyshev, Denys; Chernyakova, Maria; Pooley, Guy G.

    2017-11-01

    We have obtained a firm detection of Cyg X-1 during its hard and intermediate spectral states in the energy range of 40 MeV-60 GeV based on observations by the Fermi Large Area Telescope, confirming the independent results at ≥60 MeV of a previous work. The detection significance is ≃8σ in the 0.1-10 GeV range. In the soft state, we have found only upper limits on the emission at energies ≳0.1 MeV. However, we have found emission with a very soft spectrum in the 40-80 MeV range, not detected previously. This is likely to represent the high-energy cut-off of the high-energy power-law tail observed in the soft state. Similarly, we have detected a γ-ray soft excess in the hard state, which appears to be of similar origin. We have also confirmed the presence of an orbital modulation of the detected emission in the hard state, expected if the γ-rays are from Compton upscattering of stellar blackbody photons. However, the observed modulation is significantly weaker than that predicted if the blackbody upscattering were the dominant source of γ-rays. This argues for a significant contribution from γ-rays produced by the synchrotron self-Compton process. We have found that such strong contribution is possible if the jet is strongly clumped. We reproduce the observed hard-state average broad-band spectrum using a self-consistent jet model, taking into account all the relevant emission processes, e± pair absorption and clumping. This model also reproduces the amplitude of the observed orbital modulation.

  17. Binary and Millisecond Pulsars

    Directory of Open Access Journals (Sweden)

    Lorimer Duncan R.

    2005-11-01

    Full Text Available We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1700. There are now 80 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 103 pulsars in 24 of the Galactic globular clusters. Recent highlights have been the discovery of the first ever double pulsar system and a recent flurry of discoveries in globular clusters, in particular Terzan 5.

  18. Spectral and temporal properties of the X-ray pulsar SMC X-1 at hard X-rays

    Science.gov (United States)

    Kunz, M.; Gruber, D. E.; Kendziorra, E .; Kretschmar, P.; Maisack, M.; Mony, B.; Staubert, R.; Doebereiner, S.; Englhauser, J.; Pietsch, W.

    1993-01-01

    The binary X-ray pulsar SMC X- 1 has been observed at hard X-rays with the High Energy X-Ray Experiment (HEXE) on nine occasions between Nov. 1987 and March 1989. A thin thermal bremsstrahlung fit to the phase averaged spectrum yields a plasma temperature (14.4 +/- 1.3) keV and a luminosity above (1.1 +/- 0.1) x 10 exp 38 erg/s in the 20-80 keV band. Pulse period values have been established for three observations, confirming the remarkably stable spin-up trend of SMC X-1. In one of the three observations the pulse profile was seen to deviate from a dominant double pulsation, while at the same time the pulsed fraction was unusually large. For one observation we determined for the first time the pulsed fraction in narrow energy bands. It increases with photon energy from about 20 percent up to over 60 percent in the energy range from 20 to 80 keV.

  19. NuSTAR AND SUZAKU OBSERVATIONS OF THE HARD STATE IN CYGNUS X-1: LOCATING THE INNER ACCRETION DISK

    International Nuclear Information System (INIS)

    Parker, M. L.; Lohfink, A.; Fabian, A. C.; Alston, W. N.; Kara, E.; Tomsick, J. A.; Boggs, S. E.; Craig, W. W.; Miller, J. M.; Yamaoka, K.; Nowak, M.; Grinberg, V.; Christensen, F. E.; Fürst, F.; Grefenstette, B. W.; Harrison, F. A.; Gandhi, P.; Hailey, C. J.; King, A. L.; Stern, D.

    2015-01-01

    We present simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR ) and Suzaku observations of the X-ray binary Cygnus X-1 in the hard state. This is the first time this state has been observed in Cyg X-1 with NuSTAR, which enables us to study the reflection and broadband spectra in unprecedented detail. We confirm that the iron line cannot be fit with a combination of narrow lines and absorption features, instead requiring a relativistically blurred profile in combination with a narrow line and absorption from the companion wind. We use the reflection models of García et al. to simultaneously measure the black hole spin, disk inner radius, and coronal height in a self-consistent manner. Detailed fits to the iron line profile indicate a high level of relativistic blurring, indicative of reflection from the inner accretion disk. We find a high spin, a small inner disk radius, and a low source height and rule out truncation to greater than three gravitational radii at the 3σ confidence level. In addition, we find that the line profile has not changed greatly in the switch from soft to hard states, and that the differences are consistent with changes in the underlying reflection spectrum rather than the relativistic blurring. We find that the blurring parameters are consistent when fitting either just the iron line or the entire broadband spectrum, which is well modeled with a Comptonized continuum plus reflection model

  20. Search for gravitational redshifted absorption lines in LMXB Serpens X-1

    Science.gov (United States)

    Yoneda, Hiroki; Done, Chris; Paerels, Frits; Takahashi, Tadayuki; Watanabe, Shin

    2018-04-01

    The equation of state for ultradense matter can be tested from observations of the ratio of mass to radius of neutron stars. This could be measured precisely from the redshift of a narrow line produced on the surface. X-rays bursts have been intensively searched for such features, but so far without detection. Here instead we search for redshifted lines in the persistent emission, where the accretion flow dominates over the surface emission. We discuss the requirements for narrow lines to be produced, and show that narrow absorption lines from highly ionized iron can potentially be observable in accreting low-mass X-ray binaries (LMXBs; low B field) that have either low spin or low inclination so that Doppler broadening is small. This selects Serpens X-1 as the only potential candidate persistent LMXB due to its low inclination. Including surface models in the broad-band accretion flow model predicts that the absorption line from He-like iron at 6.7 keV should be redshifted to ˜5.1-5.7 keV (10-15 km for 1.4 M⊙) and have an equivalent width of 0.8-8 eV for surface temperatures of 7-10 × 106 K. We use the high-resolution Chandra grating data to give a firm upper limit of 2-3 eV for an absorption line at ˜5 keV. We discuss possible reasons for this lack of detection (the surface temperature and the geometry of the boundary layer etc.). Future instruments with better sensitivity are required in order to explore the existence of such features.

  1. Energy-dependent evolution in IC10 X-1: hard evidence for an extended corona and implications

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, R.; Steiner, J. F.; Prestwich, A. F. [Harvard-Smithsonian Center for Astrophysics (CFA), Cambridge, MA 02138 (United States); Stevens, I. R. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Clark, J. S.; Kolb, U. C. [The Open University, Milton Keynes (United Kingdom)

    2014-09-10

    We have analyzed a ∼130 ks XMM-Newton observation of the dynamically confirmed black hole + Wolf-Rayet (BH+WR) X-ray binary (XB) IC10 X-1, covering ∼1 orbital cycle. This system experiences periodic intensity dips every ∼35 hr. We find that energy-independent evolution is rejected at a >5σ level. The spectral and timing evolution of IC10 X-1 are best explained by a compact disk blackbody and an extended Comptonized component, where the thermal component is completely absorbed and the Comptonized component is partially covered during the dip. We consider three possibilities for the absorber: cold material in the outer accretion disk, as is well documented for Galactic neutron star (NS) XBs at high inclination; a stream of stellar wind that is enhanced by traveling through the L1 point; and a spherical wind. We estimated the corona radius (r {sub ADC}) for IC10 X-1 from the dip ingress to be ∼10{sup 6} km, assuming absorption from the outer disk, and found it to be consistent with the relation between r {sub ADC} and 1-30 keV luminosity observed in Galactic NS XBs that spans two orders of magnitude. For the other two scenarios, the corona would be larger. Prior BH mass (M {sub BH}) estimates range over 23-38 M {sub ☉}, depending on the inclination and WR mass. For disk absorption, the inclination, i, is likely to be ∼60-80°, with M {sub BH} ∼ 24-41 M {sub ☉}. Alternatively, the L1-enhanced wind requires i ∼ 80°, suggesting ∼24-33 M {sub ☉}. For a spherical absorber, i ∼ 40°, and M {sub BH} ∼ 50-65 M {sub ☉}.

  2. Participation of the Abastumani Astrophysical Observatory in Different Programs for Coordinated Investigation of Cyg X-1

    Science.gov (United States)

    Kumsiashvili, M. I.; Kochiashvili, N. T.

    2000-10-01

    Broad-band photometric observations of the black hole candidate Cyg X-1 were carried out in 1975-1998 at the Abastumani Astrophysical Observatory in the framework of coordinated observations, at the varies observatories of the former Soviet Union. All data have been reduced to a homogeneous set.Comparison of the optical and X-ray data clearly shows the existence of several kinds of variability. Analysis of the prolonged photoelectric observations of V 1357 Cyg=Cyg X-1 confirmed long-period optical variation of this X-ray binary system with the period of 294 d revealed by Kemp et al. This periodicity is most strongly pronounced at the orbital period phase when the optical star is in front of the X-ray source. Variations of the mean level of Cyg X-1 and of the light curve form with the phase of the period 294 d agree well with the model of the precessing accretion disk which radiates in the optical range mainly by scattering and processing of the optical star radiation. The direction of the disc precession coincides with that of the orbital motion and it is hard to understand this fact in the models with the forced precession. The triple system model is less probable. There are also observations of this objects made in the Abastumani Observatory in 1982-1988 which are represented the Table and light curves. These observations have not discussed by coordinators. The observations taken in the course of the International campaign "The Optical Monitoring of the Unique Astrophysical Objects" were realized by the observatories located on the territories of Georgia, Russia, Uzbekistan and Ukraine in 1994-1998. They are united in a single set, taking into account the systemic differences between them. Number of usual observations is 2247 in 399 nights in U B V R bands. The observations were performed simultaneously in X-ray band in the energy range of 2-10 keV (ASM/RXTE), and 20-100 keV (BASTE/CGRO), and also with radio observations at the Mullard radio observatory. Our

  3. Equational binary decision diagrams

    NARCIS (Netherlands)

    J.F. Groote (Jan Friso); J.C. van de Pol (Jaco)

    2000-01-01

    textabstractWe incorporate equations in binary decision diagrams (BDD). The resulting objects are called EQ-BDDs. A straightforward notion of ordered EQ-BDDs (EQ-OBDD) is defined, and it is proved that each EQ-BDD is logically equivalent to an EQ-OBDD. Moreover, on EQ-OBDDs satisfiability and

  4. Binary tense and modality

    NARCIS (Netherlands)

    Broekhuis, H.; Verkuyl, H.J

    2014-01-01

    The present paper adopts as its point of departure the claim by Te Winkel (1866) and Verkuyl (2008) that mental temporal representations are built on the basis of three binary oppositions: Present/Past, Synchronous/Posterior and Imperfect/Perfect. Te Winkel took the second opposition in terms of the

  5. N-Bit Binary Resistor

    Science.gov (United States)

    Tcheng, Ping

    1989-01-01

    Binary resistors in series tailored to precise value of resistance. Desired value of resistance obtained by cutting appropriate traces across resistors. Multibit, binary-based, adjustable resistor with high resolution used in many applications where precise resistance required.

  6. The True Ultracool Binary Fraction Using Spectral Binaries

    Science.gov (United States)

    Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Schmidt, Sarah J.; Gagné, Jonathan; Faherty, Jacqueline K.; Cruz, Kelle; Gelino, Chris

    2018-01-01

    Brown dwarfs bridge the gap between stars and giant planets. While the essential mechanisms governing their formation are not well constrained, binary statistics are a direct outcome of the formation process, and thus provide a means to test formation theories. Observational constraints on the brown dwarf binary fraction place it at 10 ‑ 20%, dominated by imaging studies (85% of systems) with the most common separation at 4 AU. This coincides with the resolution limit of state-of-the-art imaging techniques, suggesting that the binary fraction is underestimated. We have developed a separation-independent method to identify and characterize tightly-separated (dwarfs as spectral binaries by identifying traces of methane in the spectra of late-M and early-L dwarfs. Imaging follow-up of 17 spectral binaries yielded 3 (18%) resolved systems, corroborating the observed binary fraction, but 5 (29%) known binaries were missed, reinforcing the hypothesis that the short-separation systems are undercounted. In order to find the true binary fraction of brown dwarfs, we have compiled a volume-limited, spectroscopic sample of M7-L5 dwarfs and searched for T dwarf companions. In the 25 pc volume, 4 candidates were found, three of which are already confirmed, leading to a spectral binary fraction of 0.95 ± 0.50%, albeit for a specific combination of spectral types. To extract the true binary fraction and determine the biases of the spectral binary method, we have produced a binary population simulation based on different assumptions of the mass function, age distribution, evolutionary models and mass ratio distribution. Applying the correction fraction resulting from this method to the observed spectral binary fraction yields a true binary fraction of 27 ± 4%, which is roughly within 1σ of the binary fraction obtained from high resolution imaging studies, radial velocity and astrometric monitoring. This method can be extended to identify giant planet companions to young brown

  7. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  8. Learning to assign binary weights to binary descriptor

    Science.gov (United States)

    Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

    2016-10-01

    Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

  9. Processing Of Binary Images

    Science.gov (United States)

    Hou, H. S.

    1985-07-01

    An overview of the recent progress in the area of digital processing of binary images in the context of document processing is presented here. The topics covered include input scan, adaptive thresholding, halftoning, scaling and resolution conversion, data compression, character recognition, electronic mail, digital typography, and output scan. Emphasis has been placed on illustrating the basic principles rather than descriptions of a particular system. Recent technology advances and research in this field are also mentioned.

  10. Broadband X-ray spectra of the ultraluminous X-ray source Holmberg IX X-1 observed with NuSTAR, XMM-Newton, and Suzaku

    Energy Technology Data Exchange (ETDEWEB)

    Walton, D. J.; Harrison, F. A.; Grefenstette, B. W.; Fuerst, F.; Madsen, K. K.; Rana, V.; Stern, D. [Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 (United States); Miller, J. M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Bachetti, M.; Barret, D.; Webb, N. [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Boggs, S. E.; Craig, W. W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Christensen, F. E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Fabian, A. C.; Parker, M. L. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Hailey, C. J. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Ptak, A.; Zhang, W. W., E-mail: dwalton@srl.caltech.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-09-20

    We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton, and Suzaku in late 2012. These observations provide the first high-quality spectra of Holmberg IX X-1 above 10 keV to date, extending the X-ray coverage of this remarkable source up to ∼30 keV. Broadband observations were undertaken at two epochs, between which Holmberg IX X-1 exhibited both flux and strong spectral variability, increasing in luminosity from L {sub X} = (1.90 ± 0.03) × 10{sup 40} erg s{sup –1} to L {sub X} = (3.35 ± 0.03) × 10{sup 40} erg s{sup –1}. Neither epoch exhibits a spectrum consistent with emission from the standard low/hard accretion state seen in Galactic black hole binaries, which would have been expected if Holmberg IX X-1 harbors a truly massive black hole accreting at substantially sub-Eddington accretion rates. The NuSTAR data confirm that the curvature observed previously in the 3-10 keV bandpass does represent a true spectral cutoff. During each epoch, the spectrum appears to be dominated by two optically thick thermal components, likely associated with an accretion disk. The spectrum also shows some evidence for a nonthermal tail at the highest energies, which may further support this scenario. The available data allow for either of the two thermal components to dominate the spectral evolution, although both scenarios require highly nonstandard behavior for thermal accretion disk emission.

  11. Massive Black Hole Binary Evolution

    Directory of Open Access Journals (Sweden)

    Merritt David

    2005-11-01

    Full Text Available Coalescence of binary supermassive black holes (SBHs would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

  12. Binary optics: Trends and limitations

    Science.gov (United States)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-01-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  13. Particle acceleration in binaries

    Directory of Open Access Journals (Sweden)

    Sinitsyna V.G.

    2017-01-01

    Full Text Available Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV–85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.

  14. X-ray diffraction investigation of the sulphur induced 4x1 reconstruction of Ni(110)

    DEFF Research Database (Denmark)

    Foss, M.; Feidenhans'l, R.; Nielsen, M.

    1993-01-01

    The atomic structure of the Ni(110)4 x 1-S reconstruction has been determined on the basis of surface X-ray diffraction measurements. An analysis of the in-plane diffraction data shows that the model consists of Ni rows along the [001] direction, two for every 4 x 1 unit cell, corresponding to 0....

  15. CONSTRAINTS ON THE NEUTRON STAR AND INNER ACCRETION FLOW IN SERPENS X-1 USING NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J. M. [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1046 (United States); Parker, M. L.; Fabian, A. C. [Institute of Astronomy, The University of Cambridge, Madingley Road, Cambridge CB3 OHA (United Kingdom); Fuerst, F.; Grefenstette, B. W.; Tendulkar, S.; Harrison, F. A.; Rana, V. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Bachetti, M.; Barret, D. [Universite de Toulouse, UPS-OMP, Toulouse (France); Boggs, S. E.; Craig, W. W.; Tomsick, J. A. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Chakrabarty, D. [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Cambridge, MA 02139 (United States); Christensen, F. E. [Danish Technical University, Lyngby (Denmark); Hailey, C. J.; Paerels, F. [Columbia Astrophysics Laboratory and Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Natalucci, L. [Istituto di Astrofisica e Planetologia Spaziali (INAF), Via Fosso del Cavaliere 100, Roma I-00133 (Italy); Stern, D. K. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Zhang, W. W., E-mail: jonmm@umich.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-12-10

    We report on an observation of the neutron star low-mass X-ray binary Serpens X-1, made with NuSTAR. The extraordinary sensitivity afforded by NuSTAR facilitated the detection of a clear, robust, relativistic Fe K emission line from the inner disk. A relativistic profile is required over a single Gaussian line from any charge state of Fe at the 5σ level of confidence, and any two Gaussians of equal width at the same confidence. The Compton back-scattering ''hump'' peaking in the 10-20 keV band is detected for the first time in a neutron star X-ray binary. Fits with relativistically blurred disk reflection models suggest that the disk likely extends close to the innermost stable circular orbit (ISCO) or stellar surface. The best-fit blurred reflection models constrain the gravitational redshift from the stellar surface to be z {sub NS} ≥ 0.16. The data are broadly compatible with the disk extending to the ISCO; in that case, z {sub NS} ≥ 0.22 and R {sub NS} ≤ 12.6 km (assuming M {sub NS} = 1.4 M {sub ☉} and a = 0, where a = cJ/GM {sup 2}). If the star is as large or larger than its ISCO, or if the effective reflecting disk leaks across the ISCO to the surface, the redshift constraints become measurements. We discuss our results in the context of efforts to measure fundamental properties of neutron stars, and models for accretion onto compact objects.

  16. OPTICAL PROPERTIES OF THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1 AND ITS STELLAR ENVIRONMENT

    International Nuclear Information System (INIS)

    Grise, F.; Kaaret, P.; Pakull, M. W.; Motch, C.

    2011-01-01

    Holmberg IX X-1 is an archetypal ultraluminous X-ray source (ULX). Here we study the properties of the optical counterpart and of its stellar environment using optical data from SUBARU/Faint Object Camera and Spectrograph, GEMINI/GMOS-N and Hubble Space Telescope (HST)/Advanced Camera for Surveys, as well as simultaneous Chandra X-ray data. The V ∼ 22.6 spectroscopically identified optical counterpart is part of a loose cluster with an age ∼ sun . The counterpart is more luminous than the other stars of the association, suggesting a non-negligible optical contribution from the accretion disk. An observed UV excess also points to non-stellar light similar to X-ray active low-mass X-ray binaries. A broad He II λ4686 emission line identified in the optical spectrum of the ULX further suggests optical light from X-ray reprocessing in the accretion disk. Using stellar evolutionary tracks, we have constrained the mass of the counterpart to be ∼> 10 M sun , even if the accretion disk contributes significantly to the optical luminosity. Comparison of the photometric properties of the counterpart with binary models show that the donor may be more massive, ∼> 25 M sun , with the ULX system likely undergoing case AB mass transfer. Finally, the counterpart exhibits photometric variability of 0.14 mag between two HST observations separated by 50 days which could be due to ellipsoidal variations and/or disk reprocessing of variable X-ray emission.

  17. Ranked solutions of the matric equation A1X1=A2X2

    Directory of Open Access Journals (Sweden)

    A. Duane Porter

    1980-01-01

    Full Text Available Let GF(pz denote the finite field of pz elements. Let A1 be s×m of rank r1 and A2 be s×n of rank r2 with elements from GF(pz. In this paper, formulas are given for finding the number of X1,X2 over GF(pz which satisfy the matric equation A1X1=A2X2, where X1 is m×t of rank k1, and X2 is n×t of rank k2. These results are then used to find the number of solutions X1,…,Xn, Y1,…,Ym, m,n>1, of the matric equation A1X1…Xn=A2Y1…Ym.

  18. Magnetic binary nanofillers

    International Nuclear Information System (INIS)

    Morales Mendoza, N.; Goyanes, S.; Chiliotte, C.; Bekeris, V.; Rubiolo, G.; Candal, R.

    2012-01-01

    Magnetic binary nanofillers containing multiwall carbon nanotubes (MWCNT) and hercynite were synthesized by Chemical Vapor Deposition (CVD) on Fe/AlOOH prepared by the sol-gel method. The catalyst precursor was fired at 450 °C, ground and sifted through different meshes. Two powders were obtained with different particle sizes: sample A (50-75 μm) and sample B (smaller than 50 μm). These powders are composed of iron oxide particles widely dispersed in the non-crystalline matrix of aluminum oxide and they are not ferromagnetic. After reduction process the powders are composed of α-Fe nanoparticles inside hercynite matrix. These nanofillers are composed of hercynite containing α-Fe nanoparticles and MWCNT. The binary magnetic nanofillers were slightly ferromagnetic. The saturation magnetization of the nanofillers depended on the powder particle size. The nanofiller obtained from powder particles in the range 50-75 μm showed a saturation magnetization 36% higher than the one formed from powder particles smaller than 50 μm. The phenomenon is explained in terms of changes in the magnetic environment of the particles as consequence of the presence of MWCNT.

  19. Magnetic binary nanofillers

    Energy Technology Data Exchange (ETDEWEB)

    Morales Mendoza, N. [INQUIMAE, CONICET-UBA, Ciudad Universitaria, Pab2, (C1428EHA) Bs As (Argentina); LPyMC, Dep. De Fisica, FCEN-UBA and IFIBA -CONICET, Ciudad Universitaria, Cap. Fed. (Argentina); Goyanes, S. [LPyMC, Dep. De Fisica, FCEN-UBA and IFIBA -CONICET, Ciudad Universitaria, Cap. Fed. (Argentina); Chiliotte, C.; Bekeris, V. [LBT, Dep. De Fisica, FCEN-UBA. Ciudad Universitaria, Pab1, C1428EGA CABA (Argentina); Rubiolo, G. [LPyMC, Dep. De Fisica, FCEN-UBA and IFIBA -CONICET, Ciudad Universitaria, Cap. Fed. (Argentina); Unidad de Actividad Materiales, CNEA, Av Gral. Paz 1499, San Martin (1650), Prov. de Bs As (Argentina); Candal, R., E-mail: candal@qi.fcen.uba.ar [INQUIMAE, CONICET-UBA, Ciudad Universitaria, Pab2, (C1428EHA) Bs As (Argentina); Escuela de Ciencia y Tecnologia, 3iA, Universidad de Gral. San Martin, San Martin, Prov. Bs As (Argentina)

    2012-08-15

    Magnetic binary nanofillers containing multiwall carbon nanotubes (MWCNT) and hercynite were synthesized by Chemical Vapor Deposition (CVD) on Fe/AlOOH prepared by the sol-gel method. The catalyst precursor was fired at 450 Degree-Sign C, ground and sifted through different meshes. Two powders were obtained with different particle sizes: sample A (50-75 {mu}m) and sample B (smaller than 50 {mu}m). These powders are composed of iron oxide particles widely dispersed in the non-crystalline matrix of aluminum oxide and they are not ferromagnetic. After reduction process the powders are composed of {alpha}-Fe nanoparticles inside hercynite matrix. These nanofillers are composed of hercynite containing {alpha}-Fe nanoparticles and MWCNT. The binary magnetic nanofillers were slightly ferromagnetic. The saturation magnetization of the nanofillers depended on the powder particle size. The nanofiller obtained from powder particles in the range 50-75 {mu}m showed a saturation magnetization 36% higher than the one formed from powder particles smaller than 50 {mu}m. The phenomenon is explained in terms of changes in the magnetic environment of the particles as consequence of the presence of MWCNT.

  20. The high-energy pulsed X-ray spectrum of HER X-1 as observed with OSO-8. Ph.D. Thesis - Catholic Univ. of America

    Science.gov (United States)

    Maurer, G. S.; Dennis, B. R.; Coe, M. J.; Crannell, C. J.; Cutler, E. P.; Dolan, J. F.; Frost, K. J.; Orwig, L. E.

    1978-01-01

    Her X-1 was observed from 1977 August 30 to September 10 using the High-Energy X-Ray Scintillation Spectrometer on board the OSO-8 satellite. The observation, during which the source was monitored continually for nearly an entire ON-state, covered the energy range from 16 to 280 keV. Pulsed flux measurements as a function of binary orbit and binary phase are presented for energies between 16 and 98 keV. The pulsed flux between 16 and 33 keV exhibited a sharp decrease following the fourth binary orbit and was consistent with zero pulsed flux thereafter. The pulsed spectrum was fitted with a power law, a thermal spectrum without features, and a thermal spectrum with a superposed gaussian centered at 55 keV. The latter fit has the smallest value of chi - squared per degree of freedom, and the resulting integrated line intensity is 1.5 superscript + 4.1 subscript - 1.4 x .001 photons s superscript-1 cm superscript-2 for a width of 3.1 superscript + 9.1 subscript -2.6 keV. This result, while of low statistical significance, agrees with the value observed by Trumper (1978) during the same On-state.

  1. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Matthew J. Benacquista

    2013-03-01

    Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  2. Atmospheric chemistry of perfluorinated aldehyde hydrates (n-C(x)F(2x+1)CH(OH)2, x = 1, 3, 4)

    DEFF Research Database (Denmark)

    Andersen, Mads Peter Sulbæk; Toft, A.; Nielsen, O.J.

    2006-01-01

    . Bubbling CF(3)CHO/air mixtures through liquid water led to >80% conversion of CF(3)CHO into the hydrate within the approximately 2 s taken for passage through the bubbler. These results suggest that OH radical initiated oxidation of C(x)F(2x+1)CH(OH)(2) hydrates could be a significant source...

  3. Spectral properties of binary asteroids

    Science.gov (United States)

    Pajuelo, Myriam; Birlan, Mirel; Carry, Benoît; DeMeo, Francesca E.; Binzel, Richard P.; Berthier, Jérôme

    2018-04-01

    We present the first attempt to characterize the distribution of taxonomic class among the population of binary asteroids (15% of all small asteroids). For that, an analysis of 0.8-2.5{μ m} near-infrared spectra obtained with the SpeX instrument on the NASA/IRTF is presented. Taxonomic class and meteorite analog is determined for each target, increasing the sample of binary asteroids with known taxonomy by 21%. Most binary systems are bound in the S-, X-, and C- classes, followed by Q and V-types. The rate of binary systems in each taxonomic class agrees within uncertainty with the background population of small near-Earth objects and inner main belt asteroids, but for the C-types which are under-represented among binaries.

  4. Planets in Binary Star Systems

    CERN Document Server

    Haghighipour, Nader

    2010-01-01

    The discovery of extrasolar planets over the past decade has had major impacts on our understanding of the formation and dynamical evolution of planetary systems. There are features and characteristics unseen in our solar system and unexplainable by the current theories of planet formation and dynamics. Among these new surprises is the discovery of planets in binary and multiple-star systems. The discovery of such "binary-planetary" systems has confronted astrodynamicists with many new challenges, and has led them to re-examine the theories of planet formation and dynamics. Among these challenges are: How are planets formed in binary star systems? What would be the notion of habitability in such systems? Under what conditions can binary star systems have habitable planets? How will volatiles necessary for life appear on such planets? This volume seeks to gather the current research in the area of planets in binary and multistar systems and to familiarize readers with its associated theoretical and observation...

  5. RS CVn binary systems

    International Nuclear Information System (INIS)

    Linsky, J.L.

    1984-01-01

    The author attempts to place in context the vast amount of data obtained in the last few years as a result of X-ray, ultraviolet, optical, and microwave observations of RS CVn and similar spectroscopic binary systems. He concentrates on the RS CVn systems and their long-period analogs, and restricts the scope by attempting to answer on the basis of the recent data and theory following questions: (1) Are the original defining characteristics still valid and still adequate? (2) What is the evidence for discrete active regions? (3) Have we derived any meaningful physical properties for the atmospheres of RS CVn systems? (4) What are the flare observations telling us about magnetic fields in the RS CVn systems? (5) Is there evidence for systematic trends in RS CVn systems with spectral type?

  6. Evidence for an approx.300 day period in Cygnus X-1

    International Nuclear Information System (INIS)

    Priedhorsky, W.C.; Terrell, J.; Holt, S.S.

    1983-01-01

    We present the time history of X-ray emission from Cyg X-1 over an 11 year period, with 10 day resolution. The data were obtained by experiments on the Vela 5B (1969--1979) and Ariel 5 (1974--1980) satellites. Cyg X-1 varies by approx.25% with a 294 +- 4 day period. This modulation is apparently unrelated to the known transitions between the source high and low states. Flux minima occur at 1974.05+nP. The observed period is within the possible range for the precession period of an accretion disk, or of the companion star HDE 226868, in the Cyg X-1 system

  7. Effects of radiation pressure on the equipotential surfaces in X-ray binaries

    Science.gov (United States)

    Kondo, Y.; Mccluskey, G. E., Jr.; Gulden, S. L.

    1976-01-01

    Equipotential surfaces incorporating the effect of radiation pressure were computed for the X-ray binaries Cen X-3, Cyg X-1 = HDE 226868, Vela XR-1 = 3U 0900-40 = HD 77581, and 3U 1700-37 = HD 153919. The topology of the equipotential surfaces is significantly affected by radiation pressure. In particular, the so-called critical Roche (Jacobian) lobes, the traditional figure 8's, do not exist. The effects of these results on modeling X-ray binaries are discussed.

  8. Effects of radiation pressure on the equipotential surfaces in x-ray binaries

    International Nuclear Information System (INIS)

    Kondo, Y.; McCluskey, G.E. Jr.; Gulden, S.L.

    1976-01-01

    Equipotential surfaces incorporating the effect of radiation pressure were computed for the x-ray binaries Cen X-3, Cyg X-1 = HDE 226868, Vela XR-1 = 3U 0900-40 = HD 77581, and 3U 1700-37 = HD 153919. The topology of the equipotential surfaces is significantly affected by radiation pressure. In particular, the so-called critical Roche (Jacobian) lobes, the traditional figure 8's, do not exist. The effects of these results on modeling x-ray binaries are discussed

  9. The 4U 0115+63: Another energetic gamma ray binary pulsar

    Science.gov (United States)

    Chadwick, P. M.; Dipper, N. A.; Dowthwaite, J. C.; Kirkman, I. W.; Mccomb, T. J. L.; Orford, K. J.; Turver, K. E.

    1985-01-01

    Following the discovery of Her X-1 as a source of pulsed 1000 Gev X-rays, a search for emission from an X-ray binary containing a pulsar with similar values of period, period derivative and luminosity was successful. The sporadic X-ray binary 4U 0115-63 has been observed, with probability 2.5 x 10 to the minus 6 power ergs/s to emit 1000 GeV gamma-rays with a time averaged energy flux of 6 to 10 to the 35th power.

  10. The growth of Zn on a Si(1 0 0)-2x1 surface

    International Nuclear Information System (INIS)

    Xie Zhaoxiong; Tanaka, Ken-ichi

    2005-01-01

    Adsorption of Zn atoms on a Si(1 0 0)-2x1 surface was studied by scanning tunneling microscopy at room temperature. Narrow lines are grown perpendicular to the Si-dimer rows of the [1 1 0] direction at low coverage. The narrow line is formed by arraying rectangular Zn 3 dots, where a dot is composed of one Zn atom on a Si dimer and the other two in the neighboring two hollow sites. When the Si(1 0 0)-2x1 surface is covered with one monolayer of Zn, a 4x1 structure is established. More deposition of Zn on the 4x1 monolayer grows into three-dimensional Zn islands

  11. 1-deg x 1-deg Terrestrial Mean Free-Air Anomalies

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 1x1 degree Terrestrial Mean Free-Air Gravity Anomaly and Geoid Undulations Data Base was compiled and developed by the Ohio State University. This data base was...

  12. Hard X-ray observations of the Her X-1 line feature

    International Nuclear Information System (INIS)

    Manchanda, R.K.; Vialetto, G.; Bazzano, A.; La Padula, C.; Polcaro, V.F.; Ubertini, P.

    1982-01-01

    We have carried out two observations separated by a year in 1980 and 1981 during the mid-on phase of Her X-1, by using xenon filled multi-wire proportional chambers. This paper presents the time-averaged spectral results of Her X-1 in the 15-150 keV energy range. The possible case of the line centroid variability seen during 1980 experiment is also discussed. (orig./WL)

  13. Analysis of B chromosome nondisjunction induced by the r-X1 deficiency in maize.

    Science.gov (United States)

    Tseng, Shih-Hsuan; Peng, Shu-Fen; Cheng, Ya-Ming

    2017-11-20

    The maize B chromosome typically undergoes nondisjunction during the second microspore division. For normal A chromosomes, the r-X1 deficiency in maize can induce nondisjunction during the second megaspore and first microspore divisions. However, it is not known whether the r-X1 deficiency also induces nondisjunction of the maize B chromosome during these cell divisions. To answer this question, chromosome numbers were determined in the progeny of r-X1/R-r female parents carrying two B chromosomes. Some of the r-X1-lacking progeny (21.2%) contained zero or two B chromosomes. However, a much higher percentage of the r-X1-containing progeny (43.4%) exhibited zero or two B chromosomes, but none displayed more than two B chromosomes. Thus, the results indicated that the r-X1 deficiency could also induce nondisjunction of the B chromosome during the second megaspore division; moreover, the B chromosome in itself could undergo nondisjunction during the same division. In addition, pollen grains from plants with two B chromosomes lacking or exhibiting the r-X1 deficiency were compared via pollen fluorescence in situ hybridization (FISH) using a B chromosome-specific probe. The results revealed that the r-X1 deficiency could induce the occurrence of B chromosome nondisjunction during the first microspore division and that the B chromosome in itself could undergo nondisjunction during the same division at a lower frequency. Our data shed more light on the behavior of the maize B chromosome during cell division.

  14. Optimally cloned binary coherent states

    Science.gov (United States)

    Müller, C. R.; Leuchs, G.; Marquardt, Ch.; Andersen, U. L.

    2017-10-01

    Binary coherent state alphabets can be represented in a two-dimensional Hilbert space. We capitalize this formal connection between the otherwise distinct domains of qubits and continuous variable states to map binary phase-shift keyed coherent states onto the Bloch sphere and to derive their quantum-optimal clones. We analyze the Wigner function and the cumulants of the clones, and we conclude that optimal cloning of binary coherent states requires a nonlinearity above second order. We propose several practical and near-optimal cloning schemes and compare their cloning fidelity to the optimal cloner.

  15. SISTEMA DE CROMOSSOMOS SEXUAIS MÚLTIPLOS X1X1X2X2/X1X2Y NA MOSCA-DAS-FRUTAS Anastrepha sororcula (DIPTERA: TEPHRITIDAE

    Directory of Open Access Journals (Sweden)

    Inês Regina de Araújo Moura Cunha

    2014-08-01

    Full Text Available Sistemas de cromossomos sexuais simples estão difundidos entre os Tephritidae do gênero Anastrepha. Espécies deste gênero apresentam enorme importância pelo impacto que causam em frutíferas cultivadas, sobretudo no nordeste do Brasil. Análises citogenéticas desenvolvidas em Anastrepha sororcula, através da análise da estrutura cariotípica e bandamento C revelaram a presença de um sistema de cromossomos sexuais múltiplos do tipo X1X1X2X2/X1X2Y nesta espécie. Enquanto as fêmeas apresentam um cariótipo homomórfico com 2n=12, os machos possuem 2n=11, onde se destaca um grande cromossomo Y despareado. O nível de divergência cariotípica da espécie A. sororcula do nordeste, com a presença de um sistema de cromossomos sexuais múltiplos, em relação às regiões central e sudeste do Brasil, podem indicar a ocorrência de impedimentos reprodutivos entre os exemplares das duas áreas e que possivelmente, como outros exemplos que existem neste gênero, A. sororcula constitua um complexo de espécies ainda não inteiramente definido. Palavras-chave: Alossomos, peste agrícola, citogenética de insetos, heterocromatina. DOI: http://dx.doi.org/10.18561/2179-5746/biotaamazonia.v4n2p1-4

  16. No time for dead time: timing analysis of bright black hole binaries with NuSTAR

    DEFF Research Database (Denmark)

    Bachetti, Matteo; Harrison, Fiona A.; Cook, Rick

    2015-01-01

    Timing of high-count-rate sources with the NuSTAR Small Explorer Mission requires specialized analysis techniques. NuSTAR was primarily designed for spectroscopic observations of sources with relatively low count rates rather than for timing analysis of bright objects. The instrumental dead time ...... techniques. We apply this technique to NuSTAR observations of the black hole binaries GX 339-4, Cyg X-1, and GRS 1915+105....

  17. Density, viscosity, isothermal (vapour + liquid) equilibrium, excess molar volume, viscosity deviation, and their correlations for chloroform + methyl isobutyl ketone binary system

    International Nuclear Information System (INIS)

    Clara, Rene A.; Gomez Marigliano, Ana C.; Solimo, Horacio N.

    2007-01-01

    Density and viscosity measurements for pure chloroform and methyl isobutyl ketone at T = (283.15, 293.15, 303.15, and 313.15) K as well as for the binary system {x 1 chloroform + (1 - x 1 ) methyl isobutyl ketone} at the same temperatures were made over the whole concentration range. The experimental results were fitted to empirical equations, which permit the calculation of these properties over the whole concentration and temperature ranges studied. Data of the binary mixture were further used to calculate the excess molar volume and viscosity deviation. The (vapour + liquid) equilibrium (VLE) at T = 303.15 K for this binary system was also measured in order to calculate the activity coefficients and the excess molar Gibbs energy. This binary system shows no azeotrope and negative deviations from ideal behaviour. The excess or deviation properties were fitted to the Redlich-Kister polynomial relation to obtain their coefficients and standard deviations

  18. Separation in 5 Msun Binaries

    Science.gov (United States)

    Evans, Nancy R.; Bond, H. E.; Schaefer, G.; Mason, B. D.; Karovska, M.; Tingle, E.

    2013-01-01

    Cepheids (5 Msun stars) provide an excellent sample for determining the binary properties of fairly massive stars. International Ultraviolet Explorer (IUE) observations of Cepheids brighter than 8th magnitude resulted in a list of ALL companions more massive than 2.0 Msun uniformly sensitive to all separations. Hubble Space Telescope Wide Field Camera 3 (WFC3) has resolved three of these binaries (Eta Aql, S Nor, and V659 Cen). Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations for a sample of 18 Cepheids, and also a distribution of mass ratios. The distribution of orbital periods shows that the 5 Msun binaries prefer shorter periods than 1 Msun stars, reflecting differences in star formation processes.

  19. Mesoscopic model for binary fluids

    Science.gov (United States)

    Echeverria, C.; Tucci, K.; Alvarez-Llamoza, O.; Orozco-Guillén, E. E.; Morales, M.; Cosenza, M. G.

    2017-10-01

    We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.

  20. Close binary star type x-ray star and its mechanism of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hoshi, R [Rikkyo Univ., Tokyo (Japan). Dept. of Physics

    1975-09-01

    Recent progress of the study of an X-ray star is described. In 1970, the periodical emission of pulsed X-rays from Cen X-3 and Her X-1 was observed. An optically corresponding celestial object for the Cen X-3 was reported in 1973, and the mass of Cen X-3 was revised. The optical object was named after Krzeminsky. From the observed variation of luminosity, it is said that the Krzeminsky's star is deformed. This fact gave new data on the mass of the Cen X-3, and the mass is several times as large as the previously estimated value. The behavior of the Her X-1 shows four kinds of clear time variation, and indicates the characteristics of an X-ray star. The Her X-1 is an X-ray pulser the same as Cen X-3, and is a close binary star. The opposite star is known as HZ-Her, and shows weaker luminosity than the intensity of X-ray from the Her X-1. Thirty-five day period was seen in the intensity variation of X-ray. The mechanism of X-ray pulsing can be explained by material flow into a neutron star. The energy spectrum from Her X-1 is different from that from the Cen X-3. Another X-ray star, Cyg X-1, is considered to be a black hole from its X-ray spectrum.

  1. Supernova explosions in close binary systems. Pt. 2

    International Nuclear Information System (INIS)

    Sutantyo, W.

    1975-01-01

    The effects of a spherically symmetric explosion on the runaway velocity of a close binary system with an initial circular orbit is considered. It is shown that the runaway velocity is completely determined by the final orbital parameters regardless of the initial condition. The galactic z distribution of the known massive X-ray binaries indicates that the runaway velocities of these systems are very probably smaller than approximately 100 km/s with the most likely values of approximately 25-50 km/s. Such runaway velocities can be obtained if the post-explosion eccentricities are less than approximately 0.25. This then has the concequence that the mass of the exploded star which produced the neutron stars in the massive X-ray binaries can in most cases not have been larger than approximately 7-8 M(S) with the most likely values of approximately 3-4 M(S) if the supergiants in these systems have mass (M 2 ) of approximately 20 M(S). For Cyg X-1, the upper mass limit of the exploded star is found to be approximately 16 M(S). For M 2 = 30 M(S) these upper limit becomes approximately 9-10 M(S) and 19 M(S) respectively. (orig.) [de

  2. Some properties of spectral binary stars

    International Nuclear Information System (INIS)

    Krajcheva, Z.T.; Popova, E.I.; Tutukov, A.V.; Yungel'son, L.R.; AN SSSR, Moscow. Astronomicheskij Sovet)

    1978-01-01

    Statistical investigations of spectra binary stars are carried out. Binary systems consisting of main sequence stars are considered. For 826 binary stars masses of components, ratios of component masses, semiaxes of orbits and orbital angular momenta are calculated. The distributions of these parameters and their correlations are analyzed. The dependences of statistical properties of spectral binary stars on their origin and evolution are discussed

  3. Low Frequency Quasi-periodic Oscillations in the High-eccentric LMXB Cir X-1: Extending the WK Correlation for Z Sources

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Qingcui; Chen, Li [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Belloni, T. M. [INAF-Osservatorio Astronomico di Brera, Via E, Bianchi 46, I-23807 Merate (Italy); Qu, Jinlu, E-mail: buqc@mail.bnu.edu.cn, E-mail: tomaso.belloni@brera.inaf.it, E-mail: chenli@bnu.edu.cn, E-mail: qujl@ihep.ac.cn [Laboratory for Particle Astrophysics, CAS, Beijing 100049 (China)

    2017-06-01

    Using archival Rossi X-ray Timing Explorer ( RXTE ) data, we studied the low-frequency quasi-periodic oscillations (LFQPOs) in the neutron star low-mass X-ray binary (LMXB) Cir X-1 and examined their contribution to frequency–frequency correlations for Z sources. We also studied the orbital phase effects on the LFQPO properties and found them to be phase independent. Comparing LFQPO frequencies in different classes of LMXBs, we found that systems that show both Z and atoll states form a common track with atoll/BH sources in the so-called WK correlation, while persistent Z systems are offset by a factor of about two. We found that neither source luminosity nor mass accretion rate is related to the shift of persistent Z systems. We discuss the possibility of a misidentification of fundamental frequency for horizontal branch oscillations from persistent Z systems and interpreted the oscillations in terms of models based on relativistic precession.

  4. New results from Ooty EAS array for cosmic sources at PeV energies: Cygnus X-3, Crab pulsar and Sco X-1

    International Nuclear Information System (INIS)

    Tonwar, S.C.; Gupta, S.K.; Gopalakrishnan, N.V.; Rajeev, M.R.; Srivatsan, R.; Sreekantan, B.V.

    1990-01-01

    Ooty group has reported detection of a steady signal from Cyg X-3 based on observations made during 1984-86 through detection of a directional excess. Further analysis of data has revealed a significant flux enhancement during April 1986, confirming observations reported by the CYGNUS group at Los Alamos and the Baksan group. These results show conclusively that the flux from Cyg X-3 is variable over a time scale of few weeks. We also report here the details of an unusual burst from Cyg X-3, consisting of 5 showers in 13 minutes, on June 19, 1985, which shows the variability of the flux from Cyg X-3 on a much shorter time scale of few minutes. Our analysis of showers arriving from the direction of the Crab pulsar has shown only a small time-averaged excess. But these data, when folded with the Crab pulsar period, show a very significant excess at the expected phase of the optical interpulse. This is the first detection of 33 ms pulsation in the PeV energy flux from the Crab pulsar. The exact alignment of the phase of emission over nearly 20 decades of energy, from meter wavelengths to PeV, makes the Crab pulsar a really unique source to study and understand details of mechanisms for emission and acceleration of particles in compact sources. We also present here a discussion of our observations on another X-ray binary, Sco X-1. Ooty data show a very significant excess in the number of showers from the direction of Sco X-1 during a two month period in 1986, in agreement with observations reported by the Mt. Chacaltaya group. These observations establish this X-ray binary as another important source of PeV energy radiation. (orig.)

  5. Observation of short period fluctuation of CygX-1 with balloon

    International Nuclear Information System (INIS)

    Nakagawa, Michio; Sakurai, Takahisa; Uchida, Masayoshi

    1977-01-01

    CygX-1 presents very complex short period fluctuation of X-ray, therefore the hard X-ray was especially observed in 1972 and 1973 with large balloons, and the data were analyzed. This short period fluctuation and energy spectra of CygX-1 in the normal and flare time bands were compared. The observing apparatuses consisted of the 3 in diameter NaI detector and a high pressure proportional counter. The observing method is to turn the gondora alternately to the directions of source (ON) and background (OFF). As for the data analysis, the events at ON and OFF in the observation data in 1972 and 1973 were plotted for time interval. The background component is in agreement with Poisson's distribution, but source component is not. This difference for Poisson's distribution means the behavior of CygX-1. The power spectrum was analyzed, and the strong power density was observed at 5.4 x 10 -2 Hz in ON, but such power density was not observed in OFF. Accordingly this is presumed to be caused by CygX-1. The events for time interval in flare time are shown. The rise of about 2.9 σ exists at 80 msec. The count rates were compared for photon energy in the normal and flare times. The short period fluctuation of hard X-ray from CygX-1 deviates from Poisson's distribution and is different in the normal and flare times. (Nakai, Y.)

  6. 2x1 prototype plasma-electrode pockels cell (PEPC) for the National Ignition Facility

    International Nuclear Information System (INIS)

    Rhodes, M. A.

    1996-10-01

    A large aperture optical switch based on plasma electrode Pockels cell (PEPC) technology is an integral part of the National Ignition Facility (NIP) laser design. This optical switch will trap the input optical pulse in the NIF amplifier cavity for four gain passes and then switch the high-energy output optical pulse out of the cavity. The switch will consist of arrays of plasma electrode Pockels cells working in conjunction with thin-film, Brewster's angle polarizes. The 192 beams in the NIF will be arranged in 4x2 bundles. To meet the required beam-to-beam spacing within each bundle, we have proposed a NIF PEPC design based on a 4x1 mechanical module (column) which is in turn comprised of two electrically independent 2x1 PEPC units. In this paper, we report on the design a single 2x1 prototype module and experimental tests of important design issues using our single, 32 cm aperture PEPC prototype. The purpose the 2x1 prototype is to prove the viability of a 2x1 PEPC and to act, as an engineering test bed for the NIF PEPC design

  7. Binary Systems and the Initial Mass Function

    Science.gov (United States)

    Malkov, O. Yu.

    2017-07-01

    In the present paper we discuss advantages and disadvantages of binary stars, which are important for star formation history determination. We show that to make definite conclusions of the initial mass function shape, it is necessary to study binary population well enough to correct the luminosity function for unresolved binaries; to construct the mass-luminosity relation based on wide binaries data, and to separate observational mass functions of primaries, of secondaries, and of unresolved binaries.

  8. Getting high utilization of peak GFLOPS in real applications in the Cray X1

    Energy Technology Data Exchange (ETDEWEB)

    Levesque, J.M. [Cray Research, Inc., Los Alamos, NM (United States)

    2003-07-01

    This paper will show the advanced characteristics of the Cray X1 and discuss how they are used to achieve high-utilized GFLOPS on many real world applications. On most MPP systems, other than the Earth Simulator and the Cray Inc. X1, advanced scientific applications do not obtain a high percentage of peak performance, in some cases less than 2%. When this small percentage of peak is attained on the processor, one needs to have more individual processors to achieve a TFLOP of sustained performance. Larger numbers of processors result in a tremendous burden on the interconnect. Here again MPPs other than the Earth Simulator and the X1 do not have the interconnect to support the increased number of processors. Combining low processor performance with insufficient scaling results in less than desired performance for many applications. (author)

  9. Systems analysis and engineering of the X-1 Advanced Radiation Source

    International Nuclear Information System (INIS)

    Rochau, G.E.; Hands, J.A.; Raglin, P.S.; Ramirez, J.J.

    1998-01-01

    The X-1 Advanced Radiation Source, which will produce ∼ 16 MJ in x-rays, represents the next step in providing US Department of Energy's Stockpile Stewardship program with the high-energy, large volume, laboratory x-ray sources needed for the Radiation Effects Science and Simulation (RES), Inertial Confinement Fusion (ICF), and Weapon Physics (WP) Programs. Advances in fast pulsed power technology and in z-pinch hohlraums on Sandia National Laboratories' Z Accelerator in 1997 provide sufficient basis for pursuing the development of X-1. This paper will introduce the X-1 Advanced Radiation Source Facility Project, describe the systems analysis and engineering approach being used, and identify critical technology areas being researched

  10. Getting high utilization of peak GFLOPS in real applications in the Cray X1

    International Nuclear Information System (INIS)

    Levesque, J.M.

    2003-01-01

    This paper will show the advanced characteristics of the Cray X1 and discuss how they are used to achieve high-utilized GFLOPS on many real world applications. On most MPP systems, other than the Earth Simulator and the Cray Inc. X1, advanced scientific applications do not obtain a high percentage of peak performance, in some cases less than 2%. When this small percentage of peak is attained on the processor, one needs to have more individual processors to achieve a TFLOP of sustained performance. Larger numbers of processors result in a tremendous burden on the interconnect. Here again MPPs other than the Earth Simulator and the X1 do not have the interconnect to support the increased number of processors. Combining low processor performance with insufficient scaling results in less than desired performance for many applications. (author)

  11. Purinergic control of inflammation and thrombosis: Role of P2X1 receptors

    Directory of Open Access Journals (Sweden)

    Cécile Oury

    2015-01-01

    Full Text Available Inflammation shifts the hemostatic mechanisms in favor of thrombosis. Upon tissue damage or infection, a sudden increase of extracellular ATP occurs, that might contribute to the crosstalk between inflammation and thrombosis. On platelets, P2X1 receptors act to amplify platelet activation and aggregation induced by other platelet agonists. These receptors critically contribute to thrombus stability in small arteries. Besides platelets, studies by our group indicate that these receptors are expressed by neutrophils. They promote neutrophil chemotaxis, both in vitro and in vivo. In a laser-induced injury mouse model of thrombosis, it appears that neutrophils are required to initiate thrombus formation and coagulation activation on inflamed arteriolar endothelia. In this model, by using P2X1−/− mice, we recently showed that P2X1 receptors, expressed on platelets and neutrophils, play a key role in thrombus growth and fibrin generation. Intriguingly, in a model of endotoxemia, P2X1−/− mice exhibited aggravated oxidative tissue damage, along with exacerbated thrombocytopenia and increased activation of coagulation, which translated into higher susceptibility to septic shock. Thus, besides its ability to recruit neutrophils and platelets on inflamed endothelia, the P2X1 receptor also contributes to limit the activation of circulating neutrophils under systemic inflammatory conditions. Taken together, these data suggest that P2X1 receptors are involved in the interplay between platelets, neutrophils and thrombosis. We propose that activation of these receptors by ATP on neutrophils and platelets represents a new mechanism that regulates thrombo-inflammation.

  12. Gamma rays from Cygnus X-1: Modeling and nonthermal pair production

    International Nuclear Information System (INIS)

    Dermer, C.D.; Liang, E.P.

    1988-02-01

    The gamma-ray bump observed between 0.5 and 2 MeV in the spectrum of Cygnus X-1 can be interpreted as the thermal emissions from a hot (kT/approximately/400 keV) pair-dominated cloud. We argue that the X-rays and gamma rays are produced in separate emission regions, and calculate the photon-photon pair production rate from X-ray and gamma-ray interactions in the vicinity of Cyg X-1 by employing a simplified geometry for the two emitting regions

  13. Recent observations of Hercules X-1 with HEAO-1 and OSO-8

    Science.gov (United States)

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

    1979-01-01

    HEAO 1 X-ray observations of Her X-1 near an onset of the high state are discussed. An X-ray light curve is determined which indicates that for about 0.5 day before the X-ray intensity turn-on there was 1.2-sec pulsed emission from the source at a level intermediate between the high- and low-state intensities. These results are taken as demonstrating the stability in the 35-day cycle when compared with previous observations. An inconclusive search for 58-keV line emission from Her X-1 is also reported.

  14. Hidden slow pulsars in binaries

    Science.gov (United States)

    Tavani, Marco; Brookshaw, Leigh

    1993-01-01

    The recent discovery of the binary containing the slow pulsar PSR 1718-19 orbiting around a low-mass companion star adds new light on the characteristics of binary pulsars. The properties of the radio eclipses of PSR 1718-19 are the most striking observational characteristics of this system. The surface of the companion star produces a mass outflow which leaves only a small 'window' in orbital phase for the detection of PSR 1718-19 around 400 MHz. At this observing frequency, PSR 1718-19 is clearly observable only for about 1 hr out of the total 6.2 hr orbital period. The aim of this Letter is twofold: (1) to model the hydrodynamical behavior of the eclipsing material from the companion star of PSR 1718-19 and (2) to argue that a population of binary slow pulsars might have escaped detection in pulsar surveys carried out at 400 MHz. The possible existence of a population of partially or totally hidden slow pulsars in binaries will have a strong impact on current theories of binary evolution of neutron stars.

  15. The Young Visual Binary Survey

    Science.gov (United States)

    Prato, Lisa; Avilez, Ian; Lindstrom, Kyle; Graham, Sean; Sullivan, Kendall; Biddle, Lauren; Skiff, Brian; Nofi, Larissa; Schaefer, Gail; Simon, Michal

    2018-01-01

    Differences in the stellar and circumstellar properties of the components of young binaries provide key information about star and disk formation and evolution processes. Because objects with separations of a few to a few hundred astronomical units share a common environment and composition, multiple systems allow us to control for some of the factors which play into star formation. We are completing analysis of a rich sample of about 100 pre-main sequence binaries and higher order multiples, primarily located in the Taurus and Ophiuchus star forming regions. This poster will highlight some of out recent, exciting results. All reduced spectra and the results of our analysis will be publicly available to the community at http://jumar.lowell.edu/BinaryStars/. Support for this research was provided in part by NSF award AST-1313399 and by NASA Keck KPDA funding.

  16. Experimental surface charge density of the Si (100)-2x1H surface

    DEFF Research Database (Denmark)

    Ciston, J.; Marks, L.D.; Feidenhans'l, R.

    2006-01-01

    We report a three-dimensional charge density refinement from x-ray diffraction intensities of the Si (100) 2x1H surface. By paying careful attention to parameterizing the bulk Si bonding, we are able to locate the hydrogen atoms at the surface, which could not be done previously. In addition, we...

  17. Occupational Analysis Products: Operations Management- AFSC 3E6X1 (CD-ROM)

    Science.gov (United States)

    computer laser optical disc (CD-ROM); 4 3/4 in.; 23.4 MB. SYSTEMS DETAIL NOTE: ABSTRACT: This is a report of an occupational survey of the Operations ... Management (AFSC 3E6X1, OSSN 2560, Feb 04) career ladder, conducted by the Occupational Analysis Flight, AFOMS. The OSR reports the findings of current

  18. A 1Σ+ → X 1Σ+ bands of the isotopic lithium hydrides

    International Nuclear Information System (INIS)

    Li, K.C.; Stwalley, W.C.

    1977-01-01

    In order to obtain a better understanding of the X 1 Σ + ground state and the A 1 Σ + state potential energy curves of lithium hydride and to examine in detail the concept of ''mass-reduced quantum numbers'' for both an ordinary (X 1 Σ + ) and an anomalous (A 1 Σ + ) electronic state, the emission spectra of the A 1 Σ + → X 1 Σ + bands of the isotopic lithium hydrides and deuterides ere photographed in the 3000 to 5000A region with a 3.4 meter Ebert Spectrograph. The bands found involved v'' = 0 to 7 to various v' = 0 to 17 for 6 LiH, and v'' = 0 to 7 to various v' = 1 to 16 for 6 LiD. Additional bands involving v'' = 4 and 5 were also found for 7 LiH. The vibrational-rotational spectroscopic analysis of 7 LiH, 6 LiH and 6 LiD are reported here, as are the reanalyses of the 7 LiH and 7 LiD data reported by Crawford and Jorgensen. New Rydberg-Klein-Rees (RKR) A 1 Σ + and X 1 Σ + potential curves have been constructed for each individual molecule and are reported, but detailed isotopic comparisons will be reported in subsequent publications

  19. Light Curve Periodic Variability of Cyg X-1 using Jurkevich Method ...

    Indian Academy of Sciences (India)

    Abstract. The Jurkevich method is a useful method to explore periodic- ity in the unevenly sampled observational data. In this work, we adopted the method to the light curve of Cyg X-1 from 1996 to 2012, and found that there is an interesting period of 370 days, which appears in both low/hard and high/soft states.

  20. Light Curve Periodic Variability of Cyg X-1 using Jurkevich Method

    Indian Academy of Sciences (India)

    The Jurkevich method is a useful method to explore periodicity in the unevenly sampled observational data. In this work, we adopted the method to the light curve of Cyg X-1 from 1996 to 2012, and found that there is an interesting period of 370 days, which appears in both low/hard and high/soft states. That period may be ...

  1. Long term variability of Cygnus X-1. V. State definitions with all sky monitors

    NARCIS (Netherlands)

    Grinberg, V.; Hell, N.; Pottschmidt, K.; Böck, M.; Nowak, M.A.; Rodriguez, J.; Bodaghee, A.; Cadolle Bel, M.; Case, G.L.; Hanke, M.; Kühnel, M.; Markoff, S.; Pooley, G.G.; Rothschild, R.E.; Tomsick, J.A.; Wilson-Hodge, C.A.; Wilms, J.

    2013-01-01

    We present a scheme for determining the spectral state of the canonical black hole Cyg X-1 using data from previous and current X-ray all sky monitors (RXTE-ASM, Swift-BAT, MAXI, and Fermi-GBM). Determinations of the hard/intermediate and soft state agree to better than 10% between different

  2. Evolution in close binary systems

    International Nuclear Information System (INIS)

    Yungel'son, L.R.; Masevich, A.G.

    1983-01-01

    Duality is the property most typical of stars. If one investigates how prevalent double stars are, making due allowance for selection effects, one finds that as many as 90 percent of all stars are paired. Contrary to tradition it is single stars that are out of the ordinary, and as will be shown presently even some of these may have been formed by coalescence of the members of binary systems. This review deals with the evolution of close binaries, defined as double-star systems whose evolution entails exchange of material between the two components

  3. Distortion of absorption-line velocity curves due to x-ray heating in x-ray binaries

    International Nuclear Information System (INIS)

    Milgrom, M.

    1976-01-01

    The effects of X-ray heating on the measured absorption line velocities, in X-ray binaries with low X-rays to optical luminosities ratio are considered. These effects may be appreciable even for such binaries where the effect of X-ray heating on the light-curve is negligible. The effects are studied qualitatively and suggest possible ways to partially eliminate the systematic errors introduced by them. The individual systems Cyg x-1 and SMC x-1 are treated and the results of numerical calculations are presented for them. For Cyg x-1 it is found that the effect is detectable during the X-ray 'high' state in all regions of the spectrum. During the 'low' state it may be important in the red region of the spectrum. The results for the case in which soft X-ray fluxes (E < or approximately .4 keV, suggested by theoretical models) are present are also given. For SMC x-1 a strong effect for Hα, Hβ, Hγ had been found. This effect may be responsible for the observed variable velocity curve. We also find for SMC x-1 that the average X-ray intensity falling on the primary must be considerably smaller than what is derived from the detected flux, or else the effect is too large. (author)

  4. The Binary Ties that Bind

    Science.gov (United States)

    Rose, Mike

    2008-01-01

    As any reader of "About Campus" knows, binary oppositions contribute to the definitions of institutional types--the trade school versus the liberal arts college, for example. They help define disciplines and subdisciplines and the status differentials among them: consider the difference in intellectual cachet as one moves from linguistics to…

  5. Optimally cloned binary coherent states

    DEFF Research Database (Denmark)

    Mueller, C. R.; Leuchs, G.; Marquardt, Ch

    2017-01-01

    their quantum-optimal clones. We analyze the Wigner function and the cumulants of the clones, and we conclude that optimal cloning of binary coherent states requires a nonlinearity above second order. We propose several practical and near-optimal cloning schemes and compare their cloning fidelity to the optimal...

  6. Misclassification in binary choice models

    Czech Academy of Sciences Publication Activity Database

    Meyer, B. D.; Mittag, Nikolas

    2017-01-01

    Roč. 200, č. 2 (2017), s. 295-311 ISSN 0304-4076 R&D Projects: GA ČR(CZ) GJ16-07603Y Institutional support: Progres-Q24 Keywords : measurement error * binary choice models * program take-up Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 1.633, year: 2016

  7. Misclassification in binary choice models

    Czech Academy of Sciences Publication Activity Database

    Meyer, B. D.; Mittag, Nikolas

    2017-01-01

    Roč. 200, č. 2 (2017), s. 295-311 ISSN 0304-4076 Institutional support: RVO:67985998 Keywords : measurement error * binary choice models * program take-up Subject RIV: AH - Economics OBOR OECD: Economic Theory Impact factor: 1.633, year: 2016

  8. Binary logic is rich enough

    International Nuclear Information System (INIS)

    Zapatrin, R.R.

    1992-01-01

    Given a finite ortholattice L, the *-semigroup is explicitly built whose annihilator ortholattice is isomorphic to L. Thus, it is shown that any finite quantum logic is the additive part of a binary logic. Some areas of possible applications are outlined. 7 refs

  9. P2X1 Receptor Antagonists Inhibit HIV-1 Fusion by Blocking Virus-Coreceptor Interactions.

    Science.gov (United States)

    Giroud, Charline; Marin, Mariana; Hammonds, Jason; Spearman, Paul; Melikyan, Gregory B

    2015-09-01

    HIV-1 Env glycoprotein-mediated fusion is initiated upon sequential binding of Env to CD4 and the coreceptor CXCR4 or CCR5. Whereas these interactions are thought to be necessary and sufficient to promote HIV-1 fusion, other host factors can modulate this process. Previous studies reported potent inhibition of HIV-1 fusion by selective P2X1 receptor antagonists, including NF279, and suggested that these receptors play a role in HIV-1 entry. Here we investigated the mechanism of antiviral activity of NF279 and found that this compound does not inhibit HIV-1 fusion by preventing the activation of P2X1 channels but effectively blocks the binding of the virus to CXCR4 or CCR5. The notion of an off-target effect of NF279 on HIV-1 fusion is supported by the lack of detectable expression of P2X1 receptors in cells used in fusion experiments and by the fact that the addition of ATP or the enzymatic depletion of ATP in culture medium does not modulate viral fusion. Importantly, NF279 fails to inhibit HIV-1 fusion with cell lines and primary macrophages when added at an intermediate stage downstream of Env-CD4-coreceptor engagement. Conversely, in the presence of NF279, HIV-1 fusion is arrested downstream of CD4 binding but prior to coreceptor engagement. NF279 also antagonizes the signaling function of CCR5, CXCR4, and another chemokine receptor, as evidenced by the suppression of calcium responses elicited by specific ligands and by recombinant gp120. Collectively, our results demonstrate that NF279 is a dual HIV-1 coreceptor inhibitor that interferes with the functional engagement of CCR5 and CXCR4 by Env. Inhibition of P2X receptor activity suppresses HIV-1 fusion and replication, suggesting that P2X signaling is involved in HIV-1 entry. However, mechanistic experiments conducted in this study imply that P2X1 receptor is not expressed in target cells or involved in viral fusion. Instead, we found that inhibition of HIV-1 fusion by a specific P2X1 receptor antagonist, NF

  10. Astronomy of binary and multiple stars

    International Nuclear Information System (INIS)

    Tokovinin, A.A.

    1984-01-01

    Various types of binary stars and methods for their observation are described in a popular form. Some models of formation and evolution of binary and multiple star systems are presented. It is concluded that formation of binary and multiple stars is a regular stage in the process of star production

  11. Coevolution of Binaries and Circumbinary Gaseous Disks

    Science.gov (United States)

    Fleming, David; Quinn, Thomas R.

    2018-04-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.

  12. Formation and evolution of compact binaries

    NARCIS (Netherlands)

    Sluijs, Marcel Vincent van der

    2006-01-01

    In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

  13. Binary Linear-Time Erasure Decoding for Non-Binary LDPC codes

    OpenAIRE

    Savin, Valentin

    2009-01-01

    In this paper, we first introduce the extended binary representation of non-binary codes, which corresponds to a covering graph of the bipartite graph associated with the non-binary code. Then we show that non-binary codewords correspond to binary codewords of the extended representation that further satisfy some simplex-constraint: that is, bits lying over the same symbol-node of the non-binary graph must form a codeword of a simplex code. Applied to the binary erasure channel, this descript...

  14. The hard X-ray spectrum of Cyg X-1 during the transition in November 1975

    International Nuclear Information System (INIS)

    Sommer, M.; Maurus, H.; Urbach, R.

    1976-01-01

    Some observations are reported of the hard X-ray spectrum of Cyg X-1 during a transition to the high state in November 1975, made with a balloon-borne X-ray detector. The range covered was 25 to 150 keV. The data obtained appeared to confirm the characteristic spectral time variation, and suggested a single power law spectrum from 3 to 80 keV, with an increasing spectral index during the upward transition to the high state. A power spectrum is expected if it is assumed that the universe Compton effect is the basic mechanism that produces the hard X-ray tail of Cyg X-1. Spectral time variation may be caused by a varying intensity of an inner soft photon source within a stable hot cloud. (U.K.)

  15. NuSTAR discovery of a luminosity dependent cyclotron line energy in Vela X-1

    DEFF Research Database (Denmark)

    Fuerst, Felix; Pottschmidt, Katja; Wilms, Joern

    2014-01-01

    of the harmonic CRSF is correlated with flux, as expected in the sub-critical accretion regime. We argue that Vela X-1 has a very narrow accretion column with a radius of around 0.4 km that sustains a Coulomb interaction dominated shock at the observed luminosities of Lx ~ 3x10^36 erg/s. Besides the prominent...... of the line energies is variable with time and deviates significantly from 2.0, also a possible consequence of photon spawning, which changes the shape of the line. During the second observation, Vela X-1 showed a short off-state in which the power-law softened and a cut-off was no longer measurable...

  16. Short-term variability of Cyg X-1 and the accretion disk temperature fluctuation

    International Nuclear Information System (INIS)

    Doi, K.

    1980-01-01

    Recent theoretical models which have been proposed to explain the observed time-averaged spectrum of Cyg X-1 assume that the hard x-rays are emitted by inverse-Compton mechanism from an optically thin, hot accretion disk around a black hole. Results are reported here of balloon observations (20-68 keV) and compared with previous rocket observations (1.5-25 keV). Using the results an analysis is made of the variability of the source intensity in the hard x-ray range which suggests that the variation is essentially spectral indicating that it originated from temperature fluctuation in an accretive disk. Such a model, which explains the stochastic nature of the variability, its characteristic time scale and spectral features at the same time in the context of the conventional accretion disk model for Cyg X-1, is examined. (U.K.)

  17. Desorption dynamics of deuterium molecules from the Si(100)-(3x1) dideuteride surface.

    Science.gov (United States)

    Niida, T; Tsurumaki, H; Namiki, A

    2006-01-14

    We measured polar angle (theta)-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3x1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of approximately 0.25 eV, which is mostly independent of the desorption angles for 0 degreesdynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface.

  18. Adsorption of Na on Ge(001)(2x1) surface

    International Nuclear Information System (INIS)

    Xiao, H.Y.; Zu, X.T.

    2006-01-01

    The adsorption of sodium on the Ge(001)(2x1) surface at the coverage (Θ) of 0.5 and 1ML has been investigated by using ab initio total energy calculations. It was found that at Θ=0.5ML T3 and T4 sites are nearly degenerate and Na adatoms preferred to adsorb at T3 and T4 sites. This finding agrees well with Meyerheim et al.'s experimental results, but does not support theoretical investigations of Spiess et al., who found HH site was the most stable. For 1ML coverage the most stable configurations are a combination of the HH and T3 or T4 sites. Work function and dipole moment analysis showed that upon Na adsorption on Ge(001)(2x1) and Si(001)(2x1) surface the dipole-dipole repulsion is small and no depolarization effect occurs as the coverage increases from 0.5 to 1ML

  19. Optical pulstions from HZ Herculis/Hercules X-1: The self-consistent 35 day picture

    International Nuclear Information System (INIS)

    Middleditch, J.

    1983-01-01

    A detailed analysis of the optical pulsation data from HZ Her shows that all of the 35 day characteristics can be interpreted in the light of episodic mass transfer every 0.81 days lasting at least 4 hr and obscuration by a tilted accretion disk which undergoes one cycle of retrograded progression every approx.35 days. The predominant systematic shifts of the optical pulsation velocities can be related to the X-ray shadowing of the phid.7 = 0.75 side of the lobe of HZ Her by the mass transfer stream and the associated disk rim structure. In the context of this new understanding of the 35 day effects, the pulsation data strongly affirm the assumptions of prograde spin for Her X-1, and aligned corotation and Roche lobe filling for HZ Her. Consideration of the accurately measured X-ray eclipse duration and the minimum orbital co-inclination required to produce the observed 35 day optical and X-ray variability may limit the Her X-1 mass to less than 1.4 M/sub sun/. A good model atmosphere for the optical pulsations could reduce the Her X-1 mass error to less than 0.10 M/sub sun/

  20. Observation of Cyg X-1 with the K-10-11 rocket

    International Nuclear Information System (INIS)

    Doi, Tsunenari; Matsuoka, Masaru; Miyamoto, Shigenori; Oda, Minoru; Ogawara, Yoshiaki

    1976-01-01

    The X-ray emission mechanism owing to the mass accretion to compact objects is one of cosmic X-ray sources. White dwarf, neutron star and black hole are considered as the compact objects. The mass of Cyg X-1 has been estimated to be about 10 times as large as the mass of the sun, and Cyg X-1 is only one prominent candidate for the black hole. The observation of the X-ray from Cyg C-1 provides the useful information on the physical state of the black hole. Particularly, the X-ray from Cyg X-1 showed the characteristic time variations which have not been detected in other X-ray sources. They are the intensive time variation over the duration of msec to day, the pulsation of about 1 msec breadth, and the transition between two X-ray emission states. The X-ray detector abroad the K-10-11 rocket is the proportional counter filled with 90% Xe and 10% CO 2 , and covers the 1.5-2.5 kev X-ray energy range. The total detector area is about 950 cm 2 . The observed result showed the characteristic intensive time variation and the msec pulsation. The data analysis is now in progress, and the preliminary result will be reported. (Yoshimori, M.)

  1. Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1

    Science.gov (United States)

    Laurent, P.; Rodriquez, J.; Wilms, J.; Bel, M. Cadolle; Pottschmidt, K.; Grinberg, V.

    2011-01-01

    Because of their inherently high flux allowing the detection of clear signals, black hole X-ray binaries are interesting candidates for polarization studies, even if no polarization signals have been observed from them before. Such measurements would provide further detailed insight into these sources' emission mechanisms. We measured the polarization of the gamma-ray emission from the black hole binary system Cygnus X-I with the INTEGRAL/IBIS telescope. Spectral modeling ofthe data reveals two emission mechanisms: The 250-400 keY data are consistent with emission dominated by Compton scattering on thermal electrons and are weakly polarized. The second spectral component seen in the 400keV-2MeV band is by contrast strongly polarized, revealing that the MeV emission is probably related to the jet first detected in the radio band.

  2. Detecting Malicious Code by Binary File Checking

    Directory of Open Access Journals (Sweden)

    Marius POPA

    2014-01-01

    Full Text Available The object, library and executable code is stored in binary files. Functionality of a binary file is altered when its content or program source code is changed, causing undesired effects. A direct content change is possible when the intruder knows the structural information of the binary file. The paper describes the structural properties of the binary object files, how the content can be controlled by a possible intruder and what the ways to identify malicious code in such kind of files. Because the object files are inputs in linking processes, early detection of the malicious content is crucial to avoid infection of the binary executable files.

  3. Permutation Entropy for Random Binary Sequences

    Directory of Open Access Journals (Sweden)

    Lingfeng Liu

    2015-12-01

    Full Text Available In this paper, we generalize the permutation entropy (PE measure to binary sequences, which is based on Shannon’s entropy, and theoretically analyze this measure for random binary sequences. We deduce the theoretical value of PE for random binary sequences, which can be used to measure the randomness of binary sequences. We also reveal the relationship between this PE measure with other randomness measures, such as Shannon’s entropy and Lempel–Ziv complexity. The results show that PE is consistent with these two measures. Furthermore, we use PE as one of the randomness measures to evaluate the randomness of chaotic binary sequences.

  4. EVIDENCE FOR AN INTERMEDIATE-MASS BLACK HOLE IN NGC 5408 X-1

    International Nuclear Information System (INIS)

    Strohmayer, Tod E.; Mushotzky, Richard F.

    2009-01-01

    We report the discovery with XMM-Newton of correlated spectral and timing behavior in the ultraluminous X-ray source (ULX) NGC 5408 X-1. An ∼100 ks pointing with XMM/Newton obtained in 2008 January reveals a strong 10 mHz quasi-periodic oscillation (QPO) in the >1 keV flux, as well as flat-topped, band-limited noise breaking to a power law. The energy spectrum is again dominated by two components, a 0.16 keV thermal disk and a power law with an index of ∼2.5. These new measurements, combined with results from our previous 2006 January pointing in which we first detected QPOs, show for the first time in a ULX a pattern of spectral and temporal correlations strongly analogous to that seen in Galactic black hole (BH) sources, but at much higher X-ray luminosity and longer characteristic timescales. We find that the QPO frequency is proportional to the inferred disk flux, while the QPO and broadband noise amplitude (rms) are inversely proportional to the disk flux. Assuming that QPO frequency scales inversely with the BH mass at a given power-law spectral index we derive mass estimates using the observed QPO frequency-spectral index relations from five stellar-mass BH systems with dynamical mass constraints. The results from all sources are consistent with a mass range for NGC 5408 X-1 from 1000 to 9000 M sun . We argue that these are conservative limits, and a more likely range is from 2000 to 5000 M sun . Moreover, the recent relation from Gierlinski et al. that relates the BH mass to the strength of variability at high frequencies (above the break in the power spectrum) is also indicative of such a high mass for NGC 5408 X-1. Importantly, none of the above estimates appears consistent with a BH mass less than ∼1000 M sun for NGC 5408 X-1. We argue that these new findings strongly support the conclusion that NGC 5408 X-1 harbors an intermediate-mass BH.

  5. Impaired P2X1 Receptor-Mediated Adhesion in Eosinophils from Asthmatic Patients.

    Science.gov (United States)

    Wright, Adam; Mahaut-Smith, Martyn; Symon, Fiona; Sylvius, Nicolas; Ran, Shaun; Bafadhel, Mona; Muessel, Michelle; Bradding, Peter; Wardlaw, Andrew; Vial, Catherine

    2016-06-15

    Eosinophils play an important role in the pathogenesis of asthma and can be activated by extracellular nucleotides released following cell damage or inflammation. For example, increased ATP concentrations were reported in bronchoalveolar lavage fluids of asthmatic patients. Although eosinophils are known to express several subtypes of P2 receptors for extracellular nucleotides, their function and contribution to asthma remain unclear. In this article, we show that transcripts for P2X1, P2X4, and P2X5 receptors were expressed in healthy and asthmatic eosinophils. The P2X receptor agonist α,β-methylene ATP (α,β-meATP; 10 μM) evoked rapidly activating and desensitizing inward currents (peak 18 ± 3 pA/pF at -60 mV) in healthy eosinophils, typical of P2X1 homomeric receptors, which were abolished by the selective P2X1 antagonist NF449 (1 μM) (3 ± 2 pA/pF). α,β-meATP-evoked currents were smaller in eosinophils from asthmatic patients (8 ± 2 versus 27 ± 5 pA/pF for healthy) but were enhanced following treatment with a high concentration of the nucleotidase apyrase (17 ± 5 pA/pF for 10 IU/ml and 11 ± 3 pA/pF for 0.32 IU/ml), indicating that the channels are partially desensitized by extracellular nucleotides. α,β-meATP (10 μM) increased the expression of CD11b activated form in eosinophils from healthy, but not asthmatic, donors (143 ± 21% and 108 ± 11% of control response, respectively). Furthermore, α,β-meATP increased healthy (18 ± 2% compared with control 10 ± 1%) but not asthmatic (13 ± 1% versus 10 ± 0% for control) eosinophil adhesion. Healthy human eosinophils express functional P2X1 receptors whose activation leads to eosinophil αMβ2 integrin-dependent adhesion. P2X1 responses are constitutively reduced in asthmatic compared with healthy eosinophils, probably as the result of an increase in extracellular nucleotide concentration. Copyright © 2016 by The American Association of Immunologists, Inc.

  6. A ROSAT Survey of Contact Binary Stars

    Science.gov (United States)

    Geske, M. T.; Gettel, S. J.; McKay, T. A.

    2006-01-01

    Contact binary stars are common variable stars that are all believed to emit relatively large fluxes of X-rays. In this work we combine a large new sample of contact binary stars derived from the ROTSE-I telescope with X-ray data from the ROSAT All Sky Survey (RASS) to estimate the X-ray volume emissivity of contact binary stars in the Galaxy. We obtained X-ray fluxes for 140 contact binaries from the RASS, as well as two additional stars observed by the XMM-Newton observatory. From these data we confirm the emission of X-rays from all contact binary systems, with typical luminosities of approximately 1.0×1030 ergs s-1. Combining calculated luminosities with an estimated contact binary space density, we find that contact binaries do not have strong enough X-ray emission to account for a significant portion of the Galactic X-ray background.

  7. Binary evolution and observational constraints

    International Nuclear Information System (INIS)

    Loore, C. de

    1984-01-01

    The evolution of close binaries is discussed in connection with problems concerning mass and angular momentum losses. Theoretical and observational evidence for outflow of matter, leaving the system during evolution is given: statistics on total masses and mass ratios, effects of the accretion of the mass gaining component, the presence of streams, disks, rings, circumstellar envelopes, period changes, abundance changes in the atmosphere. The effects of outflowing matter on the evolution is outlined, and estimates of the fraction of matter expelled by the loser, and leaving the system, are given. The various time scales involved with evolution and observation are compared. Examples of non conservative evolution are discussed. Problems related to contact phases, on mass and energy losses, in connection with entropy changes are briefly analysed. For advanced stages the disruption probabilities for supernova explosions are examined. A global picture is given for the evolution of massive close binaries, from ZAMS, through WR phases, X-ray phases, leading to runaway pulsars or to a binary pulsar and later to a millisecond pulsar. (Auth.)

  8. Discovery of a 7 mHz X-Ray Quasi-Periodic Oscillation from the Most Massive Stellar-Mass Black Hole IC 10 X-1

    Science.gov (United States)

    Pasham, Dheeraj R.; Strohmayer, Tod E.; Mushotzky, Richard F.

    2013-01-01

    We report the discovery with XMM-Newton of an approx.. = 7 mHz X-ray (0.3-10.0 keV) quasi-periodic oscillation (QPO) from the eclipsing, high-inclination black hole binary IC 10 X-1. The QPO is significant at >4.33 sigma confidence level and has a fractional amplitude (% rms) and a quality factor, Q is identical with nu/delta nu, of approx. = 11 and 4, respectively. The overall X-ray (0.3-10.0 keV) power spectrum in the frequency range 0.0001-0.1 Hz can be described by a power-law with an index of approx. = -2, and a QPO at 7 mHz. At frequencies approx. > 0.02 Hz there is no evidence for significant variability. The fractional amplitude (rms) of the QPO is roughly energy-independent in the energy range of 0.3-1.5 keV. Above 1.5 keV the low signal-to-noise ratio of the data does not allow us to detect the QPO. By directly comparing these properties with the wide range of QPOs currently known from accreting black hole and neutron stars, we suggest that the 7 mHz QPO of IC 10 X-1 may be linked to one of the following three categories of QPOs: (1) the "heartbeat" mHz QPOs of the black hole sources GRS 1915+105 and IGR J17091-3624, or (2) the 0.6-2.4 Hz "dipper QPOs" of high-inclination neutron star systems, or (3) the mHz QPOs of Cygnus X-3.

  9. Language Learning Actions in Two 1x1 Secondary Schools in Catalonia: The Case of Online Language Resources

    Science.gov (United States)

    Calvo, Boris Vázquez; Cassany, Daniel

    2016-01-01

    This paper identifies and describes current attitudes towards classroom digitization and digital language learning practices under the umbrella of EduCAT 1x1, the One-Laptop-Per-Child (OLPC or 1x1) initiative in place in Catalonia. We thoroughly analyze practices worked out by six language teachers and twelve Compulsory Secondary Education (CSE)…

  10. Vibrational analysis of Fourier transform spectrum of the A3Π0–X1Σ ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 73; Issue 5. Vibrational analysis of Fourier transform spectrum of the A 3 0 – X 1 ∑ + and B 3 1 – X 1 ∑ + transitions of indium monobromide. Renu Singh K N Uttam M D Saksena M N Deo. Volume 73 Issue 5 November 2009 pp 889-899 ...

  11. WAS COMET C/1945 X1 (DU TOIT) A DWARF, SOHO-LIKE KREUTZ SUNGRAZER?

    Energy Technology Data Exchange (ETDEWEB)

    Sekanina, Zdenek [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Kracht, Rainer, E-mail: Zdenek.Sekanina@jpl.nasa.gov, E-mail: R.Kracht@t-online.de [Ostlandring 53, D-25335 Elmshorn, Schleswig-Holstein (Germany)

    2015-12-10

    The goal of this investigation is to reinterpret and upgrade the astrometric and other data on comet C/1945 X1, the least prominent among the Kreutz system sungrazers discovered from the ground in the twentieth century. The central issue is to appraise the pros and cons of a possibility that this object is—despite its brightness reported at discovery—a dwarf Kreutz sungrazer. We confirm Marsden’s conclusion that C/1945 X1 has a common parent with C/1882 R1 and C/1965 S1, in line with the Sekanina and Chodas scenario of their origin in the framework of the Kreutz system’s evolution. We integrate the orbit of C/1882 R1 back to the early twelfth century and then forward to around 1945 to determine the nominal direction of the line of apsides and perform a Fourier analysis to get insight into effects of the indirect planetary perturbations. To better understand the nature of C/1945 X1, its orbital motion, fate, and role in the hierarchy of the Kreutz system, as well as to attempt detecting the comet’s possible terminal outburst shortly after perihelion and answer the question in the title of this investigation, we closely examined the relevant Boyden Observatory logbooks and identified both the photographs with the comet’s known images and nearly 20 additional patrol plates, taken both before and after perihelion, on which the comet or traces of its debris will be searched for, once the process of their digitization, currently conducted as part of the Harvard College Observatory’s DASCH Project, has been completed and the scanned copies made available to the scientific community.

  12. On the Nature of the mHz X-ray Quasi-Periodic Oscillations from Ultraluminous X-ray source M82 X-1: Search for Timing-Spectral Correlations

    Science.gov (United States)

    Pasham, Dheeraj R.; Strohmayer, Tod E.

    2013-01-01

    Using all the archival XMM-Newton X-ray (3-10 keV) observations of the ultraluminous X-ray source (ULX) M82 X-1, we searched for a correlation between its variable mHz quasi-periodic oscillation (QPO) frequency and its hardness ratio (5-10 keV/3-5 keV), an indicator of the energy spectral power-law index. When stellar-mass black holes (StMBHs) exhibit type-C low-frequency QPOs (0.2-15 Hz), the centroid frequency of the QPO is known to correlate with the energy spectral index. The detection of such a correlation would strengthen the identification of M82 X-1's mHz QPOs as type-C and enable a more reliable mass estimate by scaling its QPO frequencies to those of type-C QPOs in StMBHs of known mass.We resolved the count rates and the hardness ratios of M82 X-1 and a nearby bright ULX (source 5/X42.3+59) through surface brightness modeling.We detected QPOs in the frequency range of 36-210 mHz during which M82 X-1's hardness ratio varied from 0.42 to 0.47. Our primary results are (1) that we do not detect any correlation between the mHz QPO frequency and the hardness ratio (a substitute for the energy spectral power-law index) and (2) similar to some accreting X-ray binaries, we find that M82 X-1's mHz QPO frequency increases with its X-ray count rate (Pearson's correlation coefficient = +0.97). The apparent lack of a correlation between the QPO centroid frequency and the hardness ratio poses a challenge to the earlier claims that the mHz QPOs of M82 X-1 are the analogs of the type-C low-frequency QPOs of StMBHs. On the other hand, it is possible that the observed relation between the hardness ratio and the QPO frequency represents the saturated portion of the correlation seen in type-C QPOs of StMBHs-in which case M82 X-1's mHz QPOs can still be analogous to type-C QPOs.

  13. GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

    Energy Technology Data Exchange (ETDEWEB)

    Holley-Bockelmann, Kelly [Vanderbilt University, Nashville, TN (United States); Khan, Fazeel Mahmood, E-mail: k.holley@vanderbilt.edu [Institute of Space Technology (IST), Islamabad (Pakistan)

    2015-09-10

    Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

  14. GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

    International Nuclear Information System (INIS)

    Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-01-01

    Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy

  15. SMM/HXRBS observations of Cygnus X-1 from 1986 December to 1988 April

    Science.gov (United States)

    Schwartz, R. A.; Orwig, L. E.; Dennis, B. R.; Ling, J. C.; Wheaton, W. A.

    1991-01-01

    The Solar Maximum Mission's Hard X-ray Burst Spectrometer made 30 measurements of Cygnus X-1 from December, 1986 to April, 1988, yielding a data set of broad synoptic coverage but limited duration for each data point. The hard X-ray intensity was found to be between the gamma(2) and gamma(3) levels, with a range of fluctuations about the average intensity level. The shape of the photon spectrum was found to be closest to that reported by Ling et al. (1983, 1987) during the time of the gamma(3) level emission, although the spectral shapes reported for the gamma(2) and gamma(1) levels were not precluded.

  16. Aql X-1 transition towards the soft (banana) state accompanied by radio/NIR detection

    Science.gov (United States)

    Sivakoff, G. R.; Miller-Jones, J.; Fox, O.; Linares, M.; Altamirano, D.; Russell, D.

    2009-11-01

    The currently active neutron star transient and atoll source Aql X-1 (Linares et al., ATEL #2288) has begun the transition from the hard (extreme island) state to the soft (banana) state (Rodriguez et al. ATEL #2299). This transition likely began around 2009 Nov 15 (MJD = 55150). The latest RXTE PCA observation (2009 Nov 17, MJD=55152.17+/-0.02, 2-60 keV fractional rms variability amplitude of ~11% for 0.1-10 Hz) indicates that the source is in the intermediate (island) state.

  17. The icon of defeat: the 7x1 construction by visual plasticity

    Directory of Open Access Journals (Sweden)

    Magnos Cassiano Casagrande

    2016-12-01

    Full Text Available The study investigates the 7x1 defeat of the Brazilian team in the football World Cup 2014 by the plasticity of the image. Plastic forces acting on the image analyzed by Villafañe (2000, Arnheim (1988 and Kandinsky (1997 reconstructed the fact itself. The analysis becomes more evident the strategic collaboration of the images used in newspaper front pages, in the formation of the general directions that newspaper text intends and shows the flexibility of the iconic to represent the real through visual elements such as color, point, textures and dimension.

  18. The showerfront time-structure of ''anomalous muon'' events associated with Hercules X-1

    International Nuclear Information System (INIS)

    Alexandreas, D.E.; Allen, R.C.; Biller, S.D.; Dion, G.M.; Lu, X-Q.; Vishwanath, P.R.; Yodh, G.B.; Berley, D.; Chang, C.Y.; Dingus, B.L.; Dion, C.; Goodman, J.A.; Gupta, S.K.; Haines, T.J.; Kwok, P.W.; Stark, M.J.; Burman, R.L.; Hoffman, C.M.; Lloyd-Evans, J.; Nagle, D.E.; Potter, M.E.; Sandberg, V.D.; Zhang, W.P.; Cady, D.R.; Ellsworth, R.W.; Krakauer, D.A.; Talaga, R.L.

    1990-01-01

    The 11 ''in-phase'' source events from the 1986 muon-rich bursts associated with Hercules X-1 (previously reported by this group) have been studied for indications of further anomalous behavior. The most significant effect observed resulted from an analysis of the showerfront time-structures of these events. This analysis was then applied a priori to the rest of the source day, where an additional ∼9 signal events are expected to remain. The same effect was observed at a chance probability level of ∼0.1%. 1 ref., 7 figs

  19. Vibration-rotation spectrum of BH X1Σ+ by Fourier transform emission spectroscopy

    Science.gov (United States)

    Pianalto, F. S.; O'Brien, L. C.; Keller, P. C.; Bernath, P. F.

    1988-06-01

    The vibration-rotation emission spectrum of the BH X1Σ+ state was observed with the McMath Fourier transform spectrometer at Kitt Peak. The 1-0, 2-1, and 3-2 bands were observed in a microwave discharge of B2H6 in He. Spectroscopic constants of the individual vibrational levels and equilibrium molecular constants were determined. An RKR potential curve was calculated from the equilibrium constants. Alfred P. Sloan Fellow; Camille and Henry Dreyfus Teacher-Scholar.

  20. Spin-resolved photoemission of surface states of W(110)-(1x1)H

    International Nuclear Information System (INIS)

    Hochstrasser, M.; Tobin, J.G.; Rotenberg, Eli; Kevan, S.D.

    2002-01-01

    The surface electronic states of W(110)-(1x1)H have been measured using spin- and angle-resolved photoemission. We directly demonstrate that the surface bands are both split and spin-polarized by the spin-orbit interaction in association with the loss of inversion symmetry near a surface. We observe 100 percent spin polarization of the surface states, with the spins aligned in the plane of the surface and oriented in a circular fashion relative to the S-bar symmetry point. In contrast, no measurable polarization of nearby bulk states is observed

  1. X-ray and UV spectroscopy of Cygnus X-1 = HDE226868

    Science.gov (United States)

    Pravdo, S. H.; White, N. E.; Kondo, Y.; Becker, R. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Mccluskey, B. G.

    1980-01-01

    Observations are presented of Cygnus X-1 with the solid-state spectrometer on the Einstein Observatory. The X-ray spectra of two intensity dips viewed near superior conjunction did not exhibit increased photoelectric absorption. Rather the data support a model in which an increase in the electron scattering optical depth modifies both the observed spectrum and the intensity. The characteristic temperature of the intervening material is greater than 5 x 10 to the 7th power K. These measurements were in part simultaneous with observations by IUE. The ultra violet spectrum and intensity remained relatively constant during an X-ray intensity dip.

  2. All-fiber 7x1 signal combiner for incoherent laser beam combining

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Maack, Martin D.; Skovgaard, Peter M. W.

    2011-01-01

    We demonstrate an all-fiber 7x1 signal combiner for incoherent laser beam combining. This is a potential key component for reaching several kW of stabile laser output power. The combiner couples the output from 7 single-mode (SM) fiber lasers into a single multi-mode (MM) fiber. The input signal ...... in device temperature is observed. At an intermediate power level of 600 W a beam parameter product (BPP) of 2.22 mm x mrad is measured, corresponding to an M2 value of 6.5. These values are approaching the theoretical limit dictated by brightness conservation....

  3. An extended X-ray low state from Hercules X-1

    International Nuclear Information System (INIS)

    Parmar, A.N.; White, N.E.; Barr, P.; Pietsch, W.; Truemper, J.; Voges, W.; McKechnie, S.

    1985-01-01

    Hercules X-1 exhibits a 35-day cycle in its X-ray intensity in addition to its pulsar rotational and orbital periodicities of 1.24s and 1.7 days respectively. The authors report here observations made with the EXOSAT Observatory between 1983 June and August that failed to detect the expected 35-day variation in X-ray intensity, although low-level extended X-ray emission was seen. The EXOSAT observations suggest that a temporary change in the disk structure may have occurred such that the disk was in the line of sight throughout. (author)

  4. Long-term gamma-ray spectral variability of Cygnus X-1

    International Nuclear Information System (INIS)

    Ling, J.C.; Mahoney, W.A.; Wheaton, WM.A.; Jacobson, A.S.

    1987-01-01

    Data from HEAO 3 observations of 0.05-10-MeV gamma-ray emission from Cyg X-1 during two 90-d periods (in fall 1979 and spring 1980) are compiled in tables and graphs and analyzed statistically to determine the temporal and spectral variability. It is found that a steady increase in 100-keV emission is accompanied by a decrease (and eventual disappearance) of MeV emission. The mechanisms which could theoretically be responsible for these phenomena are discussed. 28 references

  5. Free electron laser for the 2 x 1 TeV photon collider

    International Nuclear Information System (INIS)

    Sarantsev, V.P.; Yurkov, M.V.; Saldin, E.L.; Shnejdmiller, E.A.

    1993-01-01

    The two-cascade scheme of a free electron laser (FEL) of the 2 x 1 TeV photon collider is suggested. The FEL-generator having peak power of ∼ 10 MW which is amplified up to 5 x 10 11 W in the FEL-amplifier with variable parameters is used as a driving laser. Requirements for parameters of electron beam and the FEL-amplifier magnetic system are formulated on the base of calculations. 19 refs., 2 tabs., 4 figs

  6. The icon of defeat: the 7x1 construction by visual plasticity

    OpenAIRE

    Magnos Cassiano Casagrande; Fabiano Maggioni

    2016-01-01

    The study investigates the 7x1 defeat of the Brazilian team in the football World Cup 2014 by the plasticity of the image. Plastic forces acting on the image analyzed by Villafañe (2000), Arnheim (1988) and Kandinsky (1997) reconstructed the fact itself. The analysis becomes more evident the strategic collaboration of the images used in newspaper front pages, in the formation of the general directions that newspaper text intends and shows the flexibility of the iconic to represent the real th...

  7. Observation of Hercules X-1 at energies above 50 TeV

    International Nuclear Information System (INIS)

    Dingus, B.L.; Chang, C.Y.; Goodman, J.A.

    1988-01-01

    A search for emission from Hercules X-1 at energies above 50 TeV during the calendar period April 1986 to July 1987 yielded two significant bursts, on UT 24 July 1986. The events during these bursts were pulsed with a period of 1.2357 s, significantly different from estimates of the contemporaneous x-ray period. The probability that this represents random statistical fluctuations of the background is estimated to be 1/70000. The muon content of the burst events is anomalous when compared with expectations from gamma-ray showers. 11 refs., 1 fig

  8. Contribution of High-Mass Black Holes to Mergers of Compact Binaries

    International Nuclear Information System (INIS)

    Bethe, H.A.; Brown, G.E.

    1999-01-01

    We consider the merging of compact binaries consisting of a high-mass black hole and a neutron star. From stellar evolutionary calculations that include mass loss, we estimate that a zero-age main sequence (ZAMS) mass of approx-gt 80 M circle-dot is necessary before a high-mass black hole can result from a massive O star progenitor. We first consider how Cyg X-1, with its measured orbital radius of ∼17 R circle-dot , might evolve. Although this radius is substantially less than the initial distance of two O stars, it is still so large that the resulting compact objects will merge only if an eccentricity close to unity results from a high kick velocity of the neutron star in the final supernova explosion. We estimate the probability of the necessary eccentricity to be ∼1%; i.e., 99% of the time the explosion of a Cyg X-1 endash type object will end as a binary of compact stars, which will not merge in Hubble time (unless the orbit is tightened in common envelope evolution, which we discuss later). Although we predict ∼7 massive binaries of Cyg X-1 type, we argue that only Cyg X-1 is narrow enough to be observed, and that only Cyg X-1 has an appreciable chance of merging in Hubble time. This gives us a merging rate of ∼3x10 -8 yr -1 in the galaxy, the order of magnitude of the merging rate found by computer-driven population syntheses, if extrapolated to our mass limit of 80 M circle-dot ZAMS mass for high-mass black hole formation. Furthermore, in both our calculation and in those of population syntheses, almost all of the mergings involve an eccentricity close to unity in the final explosion of the O star. From this first part of our development we obtain only a negligible contribution to our final results for mergers, and it turns out to be irrelevant for our final results. In our main development, instead of relying on observed binaries, we consider the general evolution of binaries of massive stars. The critical stage is when the more massive star A has

  9. Resampling to accelerate cross-correlation searches for continuous gravitational waves from binary systems

    Science.gov (United States)

    Meadors, Grant David; Krishnan, Badri; Papa, Maria Alessandra; Whelan, John T.; Zhang, Yuanhao

    2018-02-01

    Continuous-wave (CW) gravitational waves (GWs) call for computationally-intensive methods. Low signal-to-noise ratio signals need templated searches with long coherent integration times and thus fine parameter-space resolution. Longer integration increases sensitivity. Low-mass x-ray binaries (LMXBs) such as Scorpius X-1 (Sco X-1) may emit accretion-driven CWs at strains reachable by current ground-based observatories. Binary orbital parameters induce phase modulation. This paper describes how resampling corrects binary and detector motion, yielding source-frame time series used for cross-correlation. Compared to the previous, detector-frame, templated cross-correlation method, used for Sco X-1 on data from the first Advanced LIGO observing run (O1), resampling is about 20 × faster in the costliest, most-sensitive frequency bands. Speed-up factors depend on integration time and search setup. The speed could be reinvested into longer integration with a forecast sensitivity gain, 20 to 125 Hz median, of approximately 51%, or from 20 to 250 Hz, 11%, given the same per-band cost and setup. This paper's timing model enables future setup optimization. Resampling scales well with longer integration, and at 10 × unoptimized cost could reach respectively 2.83 × and 2.75 × median sensitivities, limited by spin-wandering. Then an O1 search could yield a marginalized-polarization upper limit reaching torque-balance at 100 Hz. Frequencies from 40 to 140 Hz might be probed in equal observing time with 2 × improved detectors.

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

    Science.gov (United States)

    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.

  11. On the morphology of outbursts of accreting millisecond X-ray pulsar Aquila X-1

    Science.gov (United States)

    Güngör, C.; Ekşi, K. Y.; Göğüş, E.

    2017-10-01

    We present the X-ray light curves of the last two outbursts - 2014 & 2016 - of the well known accreting millisecond X-ray pulsar (AMXP) Aquila X-1 using the monitor of all sky X-ray image (MAXI) observations in the 2-20 keV band. After calibrating the MAXI count rates to the all-sky monitor (ASM) level, we report that the 2016 outburst is the most energetic event of Aql X-1, ever observed from this source. We show that 2016 outburst is a member of the long-high class according to the classification presented by Güngör et al. with ˜ 68 cnt/s maximum flux and ˜ 60 days duration time and the previous outburst, 2014, belongs to the short-low class with ˜ 25 cnt/s maximum flux and ˜ 30 days duration time. In order to understand differences between outbursts, we investigate the possible dependence of the peak intensity to the quiescent duration leading to the outburst and find that the outbursts following longer quiescent episodes tend to reach higher peak energetic.

  12. Molecular dynamics simulation of boron implanted into diamond (0 0 1) 2 x 1 reconstruction surface

    International Nuclear Information System (INIS)

    Li Rongbin; Dai Yongbin; Hu Xiaojun; Sheng Heshen; He Xianchang

    2003-01-01

    Molecular dynamic simulations, utilizing the Tersoff many-body potential, are used to investigate the microscopic processes of a single boron atom with energy of 500 eV implanted into the diamond (0 0 1) 2 x 1 reconstruction surface. The lifetime of thermal spike created by B bombardment is about 0.18 ps by calculating the variation of the mean coordination numbers with time. The formation of the split-interstitial composed of projectile and lattice atom (B-C) is observed. The total potential energy of the system decreases about 0.56 eV with a stable B split-interstitial in diamond. The lattice relaxations in the diamond (0 0 1) 2 x 1 reconstruction surface or near surface of simulated have been discussed. The outermost layer atoms tend to move inward, and the other atoms move outward. The interplanar distance between the outermost layer and the second layer has been shortened by 15% compared with its starting interplanar distance. Stress distribution in the calculated diamond configuration is inhomogeneous. After boron implanted into diamond with the energy of 500 eV, there is an excess of compressively stressed atoms in the lattice, which induces the total stress being compressive

  13. Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1

    Science.gov (United States)

    Marlowe, H.; Kaaret, P.; Lang, C.; Feng, H.; Grisé, F.; Miller, N.; Cseh, D.; Corbel, S.; Mushotzky, R. F.

    2014-10-01

    We observed the Ultraluminous X-ray Source (ULX) IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that is much softer than observed previously and is well modelled by a thermal accretion disc spectrum. No significant radio emission above the rms noise level was observed within the region of the ULX, consistent with the interpretation as a thermal state though other states cannot be entirely ruled out with the current data. We estimate the mass of the black hole using the modelled inner disc temperature to be 30 M_{⊙} ≲ M√{cosi}≲ 200 M_{⊙} based on a Shakura-Sunyaev disc model. Through a study of the hardness and high-energy curvature of available X-ray observations, we find that the accretion state of X-1 is not determined by luminosity alone.

  14. X1: A Robotic Exoskeleton for In-Space Countermeasures and Dynamometry

    Science.gov (United States)

    Rea, Rochelle; Beck, Christopher; Rovekamp, Roger; Diftler, Myron; Neuhaus, Peter

    2013-01-01

    Bone density loss and muscle atrophy are among the National Aeronautics and Space Administration's (NASA) highest concerns for crew health in space. Countless hours are spent maintaining an exercise regimen aboard the International Space Station (ISS) to counteract the effect of zero-gravity. Looking toward the future, NASA researchers are developing new compact and innovative exercise technologies to maintain crew health as missions increase in length and take humans further out into the solar system. The X1 Exoskeleton, initially designed for assisted mobility on Earth, was quickly theorized to have far-reaching potential as both an in-space countermeasures device and a dynamometry device to measure muscle strength. This lower-extremity device has the ability to assist or resist human movement through the use of actuators positioned at the hips and knees. Multiple points of adjustment allow for a wide range of users, all the while maintaining correct joint alignment. This paper discusses how the X1 Exoskeleton may fit NASA's onorbit countermeasures needs.

  15. Long term variability of Cygnus X-1. V. State definitions with all sky monitors

    Science.gov (United States)

    Grinberg, V.; Hell, N.; Pottschmidt, K.; Böck, M.; Nowak, M. A.; Rodriguez, J.; Bodaghee, A.; Cadolle Bel, M.; Case, G. L.; Hanke, M.; Kühnel, M.; Markoff, S. B.; Pooley, G. G.; Rothschild, R. E.; Tomsick, J. A.; Wilson-Hodge, C. A.; Wilms, J.

    2013-06-01

    We present a scheme for determining the spectral state of the canonical black hole Cyg X-1 using data from previous and current X-ray all sky monitors (RXTE-ASM, Swift-BAT, MAXI, and Fermi-GBM). Determinations of the hard/intermediate and soft state agree to better than 10% between different monitors, facilitating the determination of the state and its context for any observation of the source, potentially over the lifetimes of different individual monitors. A separation of the hard and the intermediate states, which strongly differ in their spectral shape and short-term timing behavior, is only possible when data in the soft X-rays (probability of Cyg X-1 remaining in a given state for at least one week to be larger than 85% in the hard state and larger than 75% in the soft state. Intermediate states are short lived, with a 50% probability that the source leaves the intermediate state within three days. Reliable detection of these potentially short-lived events is only possible with monitor data that have a time resolution better than 1 d.

  16. Water Induced Surface Reconstruction of the Oxygen (2x1) covered Ru(0001)

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Sabine; Cabrera-Sanfelix, Pepa; Stass, Ingeborg; Sanchez-Portal, Daniel; Arnau, Andres; Salmeron, Miquel

    2010-08-06

    Low temperature scanning tunneling microscopy (STM) and density functional theory (DFT) were used to study the adsorption of water on a Ru(0001) surface covered with half monolayer of oxygen. The oxygen atoms occupy hcp sites in an ordered structure with (2x1) periodicity. DFT predicts that water is weakly bound to the unmodified surface, 86 meV compared to the ~;;200 meV water-water H-bond. Instead, we found that water adsorption causes a shift of half of the oxygen atoms from hcp sites to fcc sites, creating a honeycomb structure where water molecules bind strongly to the exposed Ru atoms. The energy cost of reconstructing the oxygen overlayer, around 230 meV per displaced oxygen atom, is more than compensated by the larger adsorption energy of water on the newly exposed Ru atoms. Water forms hydrogen bonds with the fcc O atoms in a (4x2) superstructure due to alternating orientations of the molecules. Heating to 185 K results in the complete desorption of the water layer, leaving behind the oxygen honeycomb structure, which is metastable relative to the original (2x1). This stable structure is not recovered until after heating to temperatures close to 260K.

  17. Einstein SSS and MPC observations of Aql X-1 and 4U1820-30

    Science.gov (United States)

    Kelley, R. L.; Christian, D. J.; Schoelkopf, R. J.; Swank, J. H.

    1989-01-01

    The results of timing and spectral analyses of the X-ray sources Aql X-1 (X1908+005) and 4U1820-30 (NGC6624) are reported using data obtained with the Einstein SSS (Solid State Spectrometer) and MPC (Monitor Proportional Counter) instruments. A classic type I burst was observed from Aql X-1 in both detectors and a coherent modulation with a period of 131.66 + or - 0.02 ms and a pulsed fraction of 10 percent was detected in the SSS data. There is no evidence for a loss of coherance during the approximately 80 sec when the burst is observable. The 2 sigma upper limit on the rate of change of the pulse period is 0.00005s/s. It is argued that an asymmetrical burst occurring on a neutron star rotating at 7.6 Hz offers a plausible explanation for the oscillation. The data from 4U1820-30 show that the amplitude of the 685 sec modulation, identified as the orbital period, is independent of energy down to 0.6 keV. The SSS data show that the light curve in the 0.6 to 4.5 keV band is smoother than at higher energies.

  18. Optical spectrum of HDE 226868 = Cygnus X-1. II. Spectrophotometry and mass estimates

    International Nuclear Information System (INIS)

    Gies, D.R.; Bolton, C.T.

    1986-01-01

    In part I of this series, Gies and Bolton (1982) have presented the results of radial velocity measures of 78 high-dispersion spectrograms of HDE 226868 = Cyg X-1. For the present study, 55 of the best plates considered by Gies and Bolton were selected to form 10 average spectra. An overall mean spectrum with S/N ratio = 300 was formed by coadding the 10 averaged spectra. There is no evidence for statistically significant variations of the spectral type about the mean value of 09.7 Iab, and all the absorption line strengths are normal for the spectral type. Evidence is presented that the He II lambda 4846 emission line is formed in the stellar wind above the substellar point on the visible star. Probable values regarding the mass for the visible star and its companion are 33 and 16 solar masses, respectively. Theoretical He II lambda 4686 emission line profiles are computed for the focused stellar wind model for the Cyg X-1 system considered by Friend and Castor (1982). 105 references

  19. Activity coefficients of solutes in binary solvents

    International Nuclear Information System (INIS)

    Gokcen, N.A.

    1982-01-01

    The activity coefficients in dilute ternary systems are discussed in detail by using the Margules equations. Analyses of some relevant data at high temperatures show that the sparingly dissolved solutes in binary solvents follow complex behavior even when the binary solvents are very nearly ideal. It is shown that the activity data on the solute or the binary system cannot permit computation of the remaining activities except for the regular solutions. It is also shown that a fourth-order equation is usually adequate in expressing the activity coefficient of a solute in binary solvents at high temperatures. When the activity data for a binary solvent are difficult to obtain in a certain range of composition, the activity data for a sparingly dissolved solute can be used to supplement determination of the binary activities

  20. The use of hyperspectral data for tree species discrimination: Combining binary classifiers

    CSIR Research Space (South Africa)

    Dastile, X

    2010-11-01

    Full Text Available classifier Classification system 7 class 1 class 2 new sample For 5-nearest neighbour classification: assign new sample to class 1. RU SASA 2010 ? Given learning task {(x1,t1),(x 2,t2),?,(x p,tp)} (xi ? Rn feature vectors, ti ? {?1,?, ?c...). A review on the combination of binary classifiers in multiclass problems. Springer science and Business Media B.V [7] Dietterich T.G and Bakiri G.(1995). Solving Multiclass Learning Problem via Error-Correcting Output Codes. AI Access Foundation...

  1. Pulsar magnetospheres in binary systems

    Science.gov (United States)

    Ershkovich, A. I.; Dolan, J. F.

    1985-01-01

    The criterion for stability of a tangential discontinuity interface in a magnetized, perfectly conducting inviscid plasma is investigated by deriving the dispersion equation including the effects of both gravitational and centrifugal acceleration. The results are applied to neutron star magnetospheres in X-ray binaries. The Kelvin-Helmholtz instability appears to be important in determining whether MHD waves of large amplitude generated by instability may intermix the plasma effectively, resulting in accretion onto the whole star as suggested by Arons and Lea and leading to no X-ray pulsar behavior.

  2. The structures of binary compounds

    CERN Document Server

    Hafner, J; Jensen, WB; Majewski, JA; Mathis, K; Villars, P; Vogl, P; de Boer, FR

    1990-01-01

    - Up-to-date compilation of the experimental data on the structures of binary compounds by Villars and colleagues. - Coloured structure maps which order the compounds into their respective structural domains and present for the first time the local co-ordination polyhedra for the 150 most frequently occurring structure types, pedagogically very helpful and useful in the search for new materials with a required crystal structure. - Crystal co-ordination formulas: a flexible notation for the interpretation of solid-state structures by chemist Bill Jensen. - Recent important advances in unders

  3. Tomographic reconstruction of binary fields

    International Nuclear Information System (INIS)

    Roux, Stéphane; Leclerc, Hugo; Hild, François

    2012-01-01

    A novel algorithm is proposed for reconstructing binary images from their projection along a set of different orientations. Based on a nonlinear transformation of the projection data, classical back-projection procedures can be used iteratively to converge to the sought image. A multiscale implementation allows for a faster convergence. The algorithm is tested on images up to 1 Mb definition, and an error free reconstruction is achieved with a very limited number of projection data, saving a factor of about 100 on the number of projections required for classical reconstruction algorithms.

  4. Young and Waltzing Binary Stars

    Science.gov (United States)

    2001-10-01

    ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

  5. Microlensing Signature of Binary Black Holes

    Science.gov (United States)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  6. Survival of planets around shrinking stellar binaries.

    Science.gov (United States)

    Muñoz, Diego J; Lai, Dong

    2015-07-28

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like.

  7. Contact Binaries on Their Way Towards Merging

    Science.gov (United States)

    Gazeas, K.

    2015-07-01

    Contact binaries are the most frequently observed type of eclipsing star system. They are small, cool, low-mass binaries belonging to a relatively old stellar population. They follow certain empirical relationships that closely connect a number of physical parameters with each other, largely because of constraints coming from the Roche geometry. As a result, contact binaries provide an excellent test of stellar evolution, specifically for stellar merger scenarios. Observing campaigns by many authors have led to the cataloging of thousands of contact binaries and enabled statistical studies of many of their properties. A large number of contact binaries have been found to exhibit extraordinary behavior, requiring follow-up observations to study their peculiarities in detail. For example, a doubly-eclipsing quadruple system consisting of a contact binary and a detached binary is a highly constrained system offering an excellent laboratory to test evolutionary theories for binaries. A new observing project was initiated at the University of Athens in 2012 in order to investigate the possible lower limit for the orbital period of binary systems before coalescence, prior to merging.

  8. Identification of Human P2X1 Receptor-interacting Proteins Reveals a Role of the Cytoskeleton in Receptor Regulation*

    Science.gov (United States)

    Lalo, Ulyana; Roberts, Jonathan A.; Evans, Richard J.

    2011-01-01

    P2X1 receptors are ATP-gated ion channels expressed by smooth muscle and blood cells. Carboxyl-terminally His-FLAG-tagged human P2X1 receptors were stably expressed in HEK293 cells and co-purified with cytoskeletal proteins including actin. Disruption of the actin cytoskeleton with cytochalasin D inhibited P2X1 receptor currents with no effect on the time course of the response or surface expression of the receptor. Stabilization of the cytoskeleton with jasplakinolide had no effect on P2X1 receptor currents but decreased receptor mobility. P2X2 receptor currents were unaffected by cytochalasin, and P2X1/2 receptor chimeras were used to identify the molecular basis of actin sensitivity. These studies showed that the intracellular amino terminus accounts for the inhibitory effects of cytoskeletal disruption similar to that shown for lipid raft/cholesterol sensitivity. Stabilization of the cytoskeleton with jasplakinolide abolished the inhibitory effects of cholesterol depletion on P2X1 receptor currents, suggesting that lipid rafts may regulate the receptor through stabilization of the cytoskeleton. These studies show that the cytoskeleton plays an important role in P2X1 receptor regulation. PMID:21757694

  9. An integrated neuro-robotic interface for stroke rehabilitation using the NASA X1 powered lower limb exoskeleton.

    Science.gov (United States)

    He, Yongtian; Nathan, Kevin; Venkatakrishnan, Anusha; Rovekamp, Roger; Beck, Christopher; Ozdemir, Recep; Francisco, Gerard E; Contreras-Vidal, Jose L

    2014-01-01

    Stroke remains a leading cause of disability, limiting independent ambulation in survivors, and consequently affecting quality of life (QOL). Recent technological advances in neural interfacing with robotic rehabilitation devices are promising in the context of gait rehabilitation. Here, the X1, NASA's powered robotic lower limb exoskeleton, is introduced as a potential diagnostic, assistive, and therapeutic tool for stroke rehabilitation. Additionally, the feasibility of decoding lower limb joint kinematics and kinetics during walking with the X1 from scalp electroencephalographic (EEG) signals--the first step towards the development of a brain-machine interface (BMI) system to the X1 exoskeleton--is demonstrated.

  10. Fabricating binary optics: An overview of binary optics process technology

    Science.gov (United States)

    Stern, Margaret B.

    1993-01-01

    A review of binary optics processing technology is presented. Pattern replication techniques have been optimized to generate high-quality efficient microoptics in visible and infrared materials. High resolution optical photolithography and precision alignment is used to fabricate maximally efficient fused silica diffractive microlenses at lambda = 633 nm. The degradation in optical efficiency of four-phase-level fused silica microlenses resulting from an intentional 0.35 micron translational error has been systematically measured as a function of lens speed (F/2 - F/60). Novel processes necessary for high sag refractive IR microoptics arrays, including deep anisotropic Si-etching, planarization of deep topography and multilayer resist techniques, are described. Initial results are presented for monolithic integration of photonic and microoptic systems.

  11. Validation of X1 motorcycle model in industrial plant layout by using WITNESSTM simulation software

    Science.gov (United States)

    Hamzas, M. F. M. A.; Bareduan, S. A.; Zakaria, M. Z.; Tan, W. J.; Zairi, S.

    2017-09-01

    This paper demonstrates a case study on simulation, modelling and analysis for X1 Motorcycles Model. In this research, a motorcycle assembly plant has been selected as a main place of research study. Simulation techniques by using Witness software were applied to evaluate the performance of the existing manufacturing system. The main objective is to validate the data and find out the significant impact on the overall performance of the system for future improvement. The process of validation starts when the layout of the assembly line was identified. All components are evaluated to validate whether the data is significance for future improvement. Machine and labor statistics are among the parameters that were evaluated for process improvement. Average total cycle time for given workstations is used as criterion for comparison of possible variants. From the simulation process, the data used are appropriate and meet the criteria for two-sided assembly line problems.

  12. The smooth cyclotron line in her x-1 as seen with nuclear spectroscopic telescope array

    DEFF Research Database (Denmark)

    Fuerst, Felix; Grefenstette, Brian W.; Staubert, Ruediger

    2013-01-01

    , and a CRSF. We find that the CRSF has a very smooth and symmetric shape, in all observations and at all pulse-phases. We compare the residuals of a line with a Gaussian optical depth profile to a Lorentzian optical depth profile and find no significant differences, strongly constraining the very smooth shape....... We observed Her X-1 three times, coordinated with Suzaku, during one of the high flux intervals of its 35d super-orbital period. This paper focuses on the shape and evolution of the hard X-ray spectrum. The broad-band spectra can be fitted with a powerlaw with a high-energy cutoff, an iron line...... of the line. Even though the line energy changes dramatically with pulse phase, we find that its smooth shape does not. Additionally, our data show that the continuum is only changing marginally between the three observations. These changes can be explained with varying amounts of Thomson scattering...

  13. The smooth cyclotron line in Her X-1 as seen with NuSTAR

    DEFF Research Database (Denmark)

    Fuerst, Felix; Grefenstette, Brian W.; Staubert, Ruediger

    2013-01-01

    , and a CRSF. We find that the CRSF has a very smooth and symmetric shape, in all observations and at all pulse-phases. We compare the residuals of a line with a Gaussian optical depth profile to a Lorentzian optical depth profile and find no significant differences, strongly constraining the very smooth shape....... We observed Her X-1 three times, coordinated with Suzaku, during one of the high flux intervals of its 35d super-orbital period. This paper focuses on the shape and evolution of the hard X-ray spectrum. The broad-band spectra can be fitted with a powerlaw with a high-energy cutoff, an iron line...... of the line. Even though the line energy changes dramatically with pulse phase, we find that its smooth shape does not. Additionally, our data show that the continuum is only changing marginally between the three observations. These changes can be explained with varying amounts of Thomson scattering...

  14. Adsorption Mechanisms of NH3 on Chlorinated Si(100)-2 x 1 Surface

    International Nuclear Information System (INIS)

    Lee, Hee Soon; Choi, Cheol Ho

    2012-01-01

    The potential energy surfaces of ammonia molecule adsorptions on the symmetrically chlorinated Si(100)- 2 x 1 surface were explored with SIMOMM:MP2/6-31G(d). It was found that the initial nucleophilic attack by ammonia nitrogen to the surface Si forms a S N 2 type transition state, which eventually leads to an HCl molecular desorption. The second ammonia molecule adsorption requires much less reaction barrier, which can be rationalized by the surface cooperative effect. In general, it was shown that the surface Si-Cl bonds can be easily subjected to the substitution reactions by ammonia molecules yielding symmetric surface Si-NH 2 bonds, which can be a good initial template for subsequent surface chemical modifications. The ammonia adsorptions are in general more facile than the corresponding water adsorption, since ammonia is better nucleophile

  15. Mass-reduced quantum numbers: application to the isotopic lithium hydrides (X1B+)

    International Nuclear Information System (INIS)

    Li, K.C.; Stwalley, W.C.

    1977-01-01

    The massed-reduced quantum number (MRQN) method of combining isotopic data is applied to the lithium hydride X 1 Σ + ground state. The ΔG(eta) = μ/sup 1 / 2 / ΔG(v), B(eta) = μB(v) and D(eta) = μ 2 D(v) isotopically-combined functions are obtained. An isotopically-combined Rydberg-Klein Rees (ICRKR) potential is constructed using the G(eta) and B(eta) functions. Evidence for breakdown of the Born-Oppenheimer approximation is presented and examined. The Dunham, Simons-Parr-Finlan, and Thakkar methods of potential expansion are also applied to lithium hydride and compared to the RKR Potential

  16. RAPID PENUMBRA AND LORENTZ FORCE CHANGES IN AN X1.0 SOLAR FLARE

    International Nuclear Information System (INIS)

    Xu, Zhe; Jiang, Yunchun; Yang, Jiayang; Yang, Bo; Bi, Yi

    2016-01-01

    We present observations of the violent changes in photospheric magnetic structures associated with an X1.1 flare, which occurred in a compact δ-configuration region in the following part of AR 11890 on 2013 November 8. In both central and peripheral penumbra regions of the small δ sunspot, these changes took place abruptly and permanently in the reverse direction during the flare: the inner/outer penumbra darkened/disappeared, where the magnetic fields became more horizontal/vertical. Particularly, the Lorentz force (LF) changes in the central/peripheral region had a downward/upward and inward direction, meaning that the local pressure from the upper atmosphere was enhanced/released. It indicates that the LF changes might be responsible for the penumbra changes. These observations can be well explained as the photospheric response to the coronal field reconstruction within the framework of the magnetic implosion theory and the back reaction model of flares

  17. Three-color photometry of HDE 226868: The optical counterpart of cygnus X-1

    International Nuclear Information System (INIS)

    Lester, D.F.; Nolt, I.G.; Stearns, S.A.; Straton, P.; Radostitz, J.V.

    1976-01-01

    The results of UBV photoelectric observations of HDE 226868 (Cyg X-1) obtained on fifty nights during 1974 are presented. These observations show a light curve with the following characteristics: two unequal light maxima and minima during the 5/sup d/.6 orbital period which exhibit a peak-to-peak magnitude change of approx.0.07 mag in all colors;a small phase-dependent color variation which results in a reddening in both color indices of approx.0.003 mag at times of light minima; erratic light variability on a general time scale of days with an amplitude of +- 0.01 to 0.02 mag and no apparent color dependence

  18. Atomistic Frictional Properties of the C(1002x1-H Surface

    Directory of Open Access Journals (Sweden)

    Paul M. Jones

    2013-01-01

    Full Text Available Density functional theory- (DFT- based ab initio calculations were used to investigate the surface-to-surface interaction and frictional behavior of two hydrogenated C(100 dimer surfaces. A monolayer of hydrogen atoms was applied to the fully relaxed C(1002x1 surface having rows of C=C dimers with a bond length of 1.39 Å. The obtained C(1002x1-H surfaces (C–H bond length 1.15 Å were placed in a large vacuum space and translated toward each other. A cohesive state at a surface separation of 4.32 Å that is stabilized by approximately 0.42 eV was observed. An increase in the charge separation in the surface dimer was calculated at this separation having a 0.04 e transfer from the hydrogen atom to the carbon atom. The Mayer bond orders were calculated for the C–C and C–H bonds and were found to be 0.962 and 0.947, respectively. σ C–H bonds did not change substantially from the fully separated state. A significant decrease in the electron density difference between the hydrogen atoms on opposite surfaces was seen and assigned to the effects of Pauli repulsion. The surfaces were translated relative to each other in the (100 plane, and the friction force was obtained as a function of slab spacing, which yielded a 0.157 coefficient of friction.

  19. Comparison of Knee and Ankle Dynamometry between NASA's X1 Exoskeleton and Biodex System 4

    Science.gov (United States)

    English, K. L.; Newby, N. J.; Hackney, K. J.; DeWitt, J. K.; Beck, C. E.; Rovekamp, R. N.; Rea, R. L.; Ploutz-Snyder, L. L.

    2014-01-01

    Pre- and post-flight dynamometry is performed on International Space Station crewmembers to characterize microgravity-induced strength changes. Strength is not assessed in flight due to hardware limitations and there is poor understanding of the time course of in-flight changes. PURPOSE: To assess the reliability of a prototype dynamometer, the X1 Exoskeleton (EXO) and its agreement with a Biodex System 4 (BIO). METHODS: Eight subjects (4 M/4 F) completed 2 counterbalanced testing sessions of knee extension/flexion (KE/KF), 1 with BIO and 1 with EXO, with repeated measures within each session in normal gravity. Test-retest reliability (test 1 and 2) and device agreement (BIO vs. EXO) were evaluated. Later, to assess device agreement for ankle plantarflexion (PF), 10 subjects (4 M/6 F) completed 3 test conditions (BIO, EXO, and BIOEXO); BIOEXO was a hybrid condition comprised of the Biodex dynamometer motor and the X1 footplate and ankle frame. Ankle comparisons were: BIO vs. BIOEXO (footplate differences), BIOEXO vs. EXO (motor differences), and BIO vs. EXO (all differences). Reliability for KE/KF was determined by intraclass correlation (ICC). Device agreement was assessed with: 1) repeated measures ANOVA, 2) a measure of concordance (rho), and 3) average difference. RESULTS: ICCs for KE/KF were 0.99 for BIO and 0.96 to 0.99 for EXO. Agreement was high for KE (concordance: 0.86 to 0.95; average differences: -7 to +9 Nm) and low to moderate for KF (concordance: 0.64 to 0.78; average differences: -4 to -29 Nm, Pexoskeleton to perform portable dynamometry for large muscle groups of the lower body.

  20. Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC/R), AFSC 3E1X1. OSSN 2368

    National Research Council Canada - National Science Library

    1999-01-01

    Survey Coverage: The Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC/R) career ladder, AFSC 3E1X1, was surveyed to gather data needed to guide the development and evaluation of training...

  1. Radial Velocities of 41 Kepler Eclipsing Binaries

    Science.gov (United States)

    Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Williams, Stephen J.

    2017-12-01

    Eclipsing binaries are vital for directly determining stellar parameters without reliance on models or scaling relations. Spectroscopically derived parameters of detached and semi-detached binaries allow us to determine component masses that can inform theories of stellar and binary evolution. Here we present moderate resolution ground-based spectra of stars in close binary systems with and without (detected) tertiary companions observed by NASA’s Kepler mission and analyzed for eclipse timing variations. We obtain radial velocities and spectroscopic orbits for five single-lined and 35 double-lined systems, and confirm one false positive eclipsing binary. For the double-lined spectroscopic binaries, we also determine individual component masses and examine the mass ratio {M}2/{M}1 distribution, which is dominated by binaries with like-mass pairs and semi-detached classical Algol systems that have undergone mass transfer. Finally, we constrain the mass of the tertiary component for five double-lined binaries with previously detected companions.

  2. BHDD: Primordial black hole binaries code

    Science.gov (United States)

    Kavanagh, Bradley J.; Gaggero, Daniele; Bertone, Gianfranco

    2018-06-01

    BHDD (BlackHolesDarkDress) simulates primordial black hole (PBH) binaries that are clothed in dark matter (DM) halos. The software uses N-body simulations and analytical estimates to follow the evolution of PBH binaries formed in the early Universe.

  3. Main Memory Implementations for Binary Grouping

    OpenAIRE

    May, Norman; Moerkotte, Guido

    2005-01-01

    An increasing number of applications depend on efficient storage and analysis features for XML data. Hence, query optimization and efficient evaluation techniques for the emerging XQuery standard become more and more important. Many XQuery queries require nested expressions. Unnesting them often introduces binary grouping. We introduce several algorithms implementing binary grouping and analyze their time and space complexity. Experiments demonstrate their performance.

  4. Eliciting Subjective Probabilities with Binary Lotteries

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Martínez-Correa, Jimmy; Swarthout, J. Todd

    objective probabilities. Drawing a sample from the same subject population, we find evidence that the binary lottery procedure induces linear utility in a subjective probability elicitation task using the Quadratic Scoring Rule. We also show that the binary lottery procedure can induce direct revelation...

  5. Bondi-Hoyle-Lyttleton Accretion onto Binaries

    Science.gov (United States)

    Antoni, Andrea; MacLeod, Morgan; Ramírez-Ruiz, Enrico

    2018-01-01

    Binary stars are not rare. While only close binary stars will eventually interact with one another, even the widest binary systems interact with their gaseous surroundings. The rates of accretion and the gaseous drag forces arising in these interactions are the key to understanding how these systems evolve. This poster examines accretion flows around a binary system moving supersonically through a background gas. We perform three-dimensional hydrodynamic simulations of Bondi-Hoyle-Lyttleton accretion using the adaptive mesh refinement code FLASH. We simulate a range of values of semi-major axis of the orbit relative to the gravitational focusing impact parameter of the pair. On large scales, gas is gravitationally focused by the center-of-mass of the binary, leading to dynamical friction drag and to the accretion of mass and momentum. On smaller scales, the orbital motion imprints itself on the gas. Notably, the magnitude and direction of the forces acting on the binary inherit this orbital dependence. The long-term evolution of the binary is determined by the timescales for accretion, slow down of the center-of-mass, and decay of the orbit. We use our simulations to measure these timescales and to establish a hierarchy between them. In general, our simulations indicate that binaries moving through gaseous media will slow down before the orbit decays.

  6. Binary Relations as a Foundation of Mathematics

    NARCIS (Netherlands)

    Kuper, Jan; Barendsen, E.; Capretta, V.; Geuvers, H.; Niqui, M.

    2007-01-01

    We describe a theory for binary relations in the Zermelo-Fraenkel style. We choose for ZFCU, a variant of ZFC Set theory in which the Axiom of Foundation is replaced by an axiom allowing for non-wellfounded sets. The theory of binary relations is shown to be equi-consistent ZFCU by constructing a

  7. RELATIONSHIP BETWEEN FLASH POINTS OF SOME BINARY ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    Miscellaneous binary blends containing solvent neutral-150 (SN-150), ... viscosity, the flash point test has always been a standard part of a lubricant's specification. ... between structure and flash points of organic compounds [5-12] and fuels [13, 14]. ... in binary mixtures, the gaps between flash points would be high enough.

  8. The origin of the RS CVn binaries

    International Nuclear Information System (INIS)

    Biermann, P.

    1976-01-01

    Six possible origins for the RS CVn binaries are considered based on the following possibilities. RS CVn binaries might now be either pre-main-sequence or post-main-sequence. A pre-main-sequence binary might not always have been a binary but might have resulted from fission of a rapidly rotating single pre-main-sequence star. The main-sequence counterparts might be either single stars or binaries. To decide which of the six origins is possible, the following observed data for the RS CVn binaries are considered: total mass, total angular momentum, lack of observed connection with regions of star formation, large space density, kinematical age, and the visual companion of WW Dra. In addition lifetimes and space densities of single stars and other types of binaries are considered. The only origin possible is that the RS CVn binaries are in a thermal phase following fission of a main-sequence single star. In this explanation the single star had a rapidly rotating core which became unstable due to the core contraction which made it begin to evolve off the main sequence. The present Be stars might be examples of such parent single stars. (Auth.)

  9. A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.

    Science.gov (United States)

    Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu

    2017-08-02

    In order to study the dynamics of the reaction H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), a new potential energy surface (PES) for the ground state of the NaH 2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H 2 (X 1 Σ g + ) and NaH(X 1 Σ + ) obtained on the new NaH 2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH 2 system, the NaH 2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction. Because the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction releases more energy, the product molecules can be excited to a higher vibrational state.

  10. Experimental and theoretical excess molar enthalpies of ternary and binary mixtures containing 2-Methoxy-2-Methylpropane, 1-propanol, heptane

    International Nuclear Information System (INIS)

    Mato, Marta M.; Cebreiro, Susana M.; Paz Andrade, María Inmaculada; Legido, José Luis

    2013-01-01

    Highlights: • Experimental enthalpies for the ternary system MTBE + propanol + heptane were measured. • No experimental ternary values were found in the currently available literature. • Experimental enthalpies for the binary system propanol + heptane were measured. • Excess molar enthalpies are positive over the whole range of composition. • The ternary contribution is also positive, and the representation is asymmetric. -- Abstract: Excess molar enthalpies, at the temperature of 298.15 K and atmospheric pressure, have been measured for the ternary system {x 1 2-Methoxy-2-Methylpropane (MTBE) + x 2 1-propanol + (1 − x 1 − x 2 ) heptane}, over the whole composition range. Also, experimental data of excess molar enthalpy for the involved binary mixture {x 1-propanol + (1 − x) heptane} at the 298.15 K and atmospheric pressure, are reported. We are not aware of any previous experimental measurement of excess enthalpy in the literature for the ternary system presented in this study. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The ternary contribution to the excess enthalpy was correlated with the equation due to Morris et al. (1975) [15], and the equation proposed by Myers–Scott (1963) [14] was used to fitted the experimental binary mixture measured in this work. Additionally, the experimental results are compared with the estimations obtained by applying the group contribution model of UNIFAC, in the versions of Larsen et al. (1987) [16] and Gmehling et al. (1993) [17]. Several empirical expressions for estimating ternary properties from binary results were also tested

  11. Mass Transfer in Mira-Type Binaries

    Directory of Open Access Journals (Sweden)

    Mohamed S.

    2012-06-01

    Full Text Available Detached, symbiotic binaries are generally assumed to interact via Bondi-Hoyle-Littleton (BHL wind accretion. However, the accretion rates and outflow geometries that result from this mass-transfer mechanism cannot adequately explain the observations of the nearest and best studied symbiotic binary, Mira, or the formation of some post-AGB binaries, e.g. barium stars. We propose a new mass-transfer mode for Mira-type binaries, which we call ‘wind Roche-lobe overflow’ (WRLOF, and which we demonstrate with 3D hydrodynamic simulations. Importantly, we show that the circumstellar outflows which result from WRLOF tend to be highly aspherical and strongly focused towards the binary orbital plane. Furthermore, the subsequent mass-transfer rates are at least an order of magnitude greater than the analogous BHL values. We discuss the implications of these results for the shaping of bipolar (proto-planetary nebulae and other related systems.

  12. Logistic chaotic maps for binary numbers generations

    International Nuclear Information System (INIS)

    Kanso, Ali; Smaoui, Nejib

    2009-01-01

    Two pseudorandom binary sequence generators, based on logistic chaotic maps intended for stream cipher applications, are proposed. The first is based on a single one-dimensional logistic map which exhibits random, noise-like properties at given certain parameter values, and the second is based on a combination of two logistic maps. The encryption step proposed in both algorithms consists of a simple bitwise XOR operation of the plaintext binary sequence with the keystream binary sequence to produce the ciphertext binary sequence. A threshold function is applied to convert the floating-point iterates into binary form. Experimental results show that the produced sequences possess high linear complexity and very good statistical properties. The systems are put forward for security evaluation by the cryptographic committees.

  13. Phonons in fcc binary alloys

    International Nuclear Information System (INIS)

    Sharma, Amita; Rathore, R.P.S.

    1992-01-01

    Born-Mayer potential has been modified to account for the unpaired (three body) forces among the common nearest neighbours of the ordered binary fcc alloys i.e. Ni 3 Fe 7 , Ni 5 Fe 5 and Ni 75 Fe 25 . The three body potential is added to the two body form of Morse to formalize the total interaction potential. Measured inverse ionic compressibility, cohesive energy, lattice constant and one measured phonon frequency are used to evaluate the defining parameters of the potential. The potential seeks to bring about the binding among 140 and 132 atoms though pair wise (two body) and non-pair wise (three body) forces respectively. The phonon-dispersion relations obtained by solving the secular equation are compared with the experimental findings on the aforesaid alloys. (author). 19 refs., 3 figs

  14. Optical eclipses and precessional effects in the X-ray binary system HD 77581=4U 0900-40

    International Nuclear Information System (INIS)

    Khruzina, T.S.; Cherepashchuk, A.M.

    1982-01-01

    The longperiod (P=93.3sup(d)) variability of the amplitude and shape of the optical light curves of the X-ray binary HD 77581 has been discovered from the analysis of all published photometric data. The 93.3-day period is presumably the period of the forced precession of the rotational axis of the optical star. It is shown that the system HD 77581 appears to be an eclipsing binary in the optical range with the amplitude of the ellipsoidal variability approximately 0sup(m).04 and the depth of the eclipse reaching approximately 0sup(m).04. The eclipses are caused by the gaseous streams and the accreting structure, the orientation of which in the binary system is varying with the precession period of the optical star. The estimates of the parameters of the system are obtained. It is shown that the parameter of the Roche Lobe filling for the optical star is μ < 1. The mass of the neutron star is Msub(x)=(1.6+-0.3) Msub(Sun), where Msub(Sun) is the solar mass. The forced precession of the optical star is connected with the non-perpendicularity of its rotational axis to the orbit plane of the binary system. This non-perpendicularity may be a result of supernova explosion in a close binary system

  15. The Bacterial Effector HopX1 Targets JAZ Transcriptional Repressors to Activate Jasmonate Signaling and Promote Infection in Arabidopsis

    Science.gov (United States)

    Gimenez-Ibanez, Selena; Boter, Marta; Fernández-Barbero, Gemma; Chini, Andrea; Rathjen, John P.; Solano, Roberto

    2014-01-01

    Pathogenicity of Pseudomonas syringae is dependent on a type III secretion system, which secretes a suite of virulence effector proteins into the host cytoplasm, and the production of a number of toxins such as coronatine (COR), which is a mimic of the plant hormone jasmonate-isoleuce (JA-Ile). Inside the plant cell, effectors target host molecules to subvert the host cell physiology and disrupt defenses. However, despite the fact that elucidating effector action is essential to understanding bacterial pathogenesis, the molecular function and host targets of the vast majority of effectors remain largely unknown. Here, we found that effector HopX1 from Pseudomonas syringae pv. tabaci (Pta) 11528, a strain that does not produce COR, interacts with and promotes the degradation of JAZ proteins, a key family of JA-repressors. We show that hopX1 encodes a cysteine protease, activity that is required for degradation of JAZs by HopX1. HopX1 associates with JAZ proteins through its central ZIM domain and degradation occurs in a COI1-independent manner. Moreover, ectopic expression of HopX1 in Arabidopsis induces the expression of JA-dependent genes, represses salicylic acid (SA)-induced markers, and complements the growth of a COR-deficient P. syringae pv. tomato (Pto) DC3000 strain during natural bacterial infections. Furthermore, HopX1 promoted susceptibility when delivered by the natural type III secretion system, to a similar extent as the addition of COR, and this effect was dependent on its catalytic activity. Altogether, our results indicate that JAZ proteins are direct targets of bacterial effectors to promote activation of JA-induced defenses and susceptibility in Arabidopsis. HopX1 illustrates a paradigm of an alternative evolutionary solution to COR with similar physiological outcome. PMID:24558350

  16. PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

    International Nuclear Information System (INIS)

    Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

    2015-01-01

    Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods

  17. Topological and categorical properties of binary trees

    Directory of Open Access Journals (Sweden)

    H. Pajoohesh

    2008-04-01

    Full Text Available Binary trees are very useful tools in computer science for estimating the running time of so-called comparison based algorithms, algorithms in which every action is ultimately based on a prior comparison between two elements. For two given algorithms A and B where the decision tree of A is more balanced than that of B, it is known that the average and worst case times of A will be better than those of B, i.e., ₸A(n ≤₸B(n and TWA (n≤TWB (n. Thus the most balanced and the most imbalanced binary trees play a main role. Here we consider them as semilattices and characterize the most balanced and the most imbalanced binary trees by topological and categorical properties. Also we define the composition of binary trees as a commutative binary operation, *, such that for binary trees A and B, A * B is the binary tree obtained by attaching a copy of B to any leaf of A. We show that (T,* is a commutative po-monoid and investigate its properties.

  18. LONG-TERM EVOLUTION OF THE MAIN-ON STATES IN HERCULES X-1

    Energy Technology Data Exchange (ETDEWEB)

    Šimon, Vojtech, E-mail: simon@asu.cas.cz [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov (Czech Republic)

    2015-07-15

    Rossi X-ray Timing Explorer All-sky Monitor (RXTE ASM) observations and American Association of Variable Star Observers (AAVSO) optical data were used for a time-series analysis of the long-term activity of Her X-1. The problem of measuring the long-term evolution of the X-ray intensity in the light curve which consists only of separated intense spikes was addressed. For this purpose, the fluence of each Main-On state was determined. The fluences vary generally (not only in the transitions into/from anomalous low states (ALSs)) by tens of percent on timescales of at least several epochs of the cycle length of the superorbital cycle (but without any stable cycle) while irradiation of the donor producing the optical modulation remains considerably more stable. ALS1 and ALS2 are extensions of the tail in the statistical distribution of these fluences. In this interpretation, the variations of the fluences are caused by the changes of the structure of the inner disk region, which produces variable obscuration of the beams (emitting in the ASM band) at the neutron star. A small change of obscuration of these beams by the inner disk region suffices to change the fluences largely. However, the irradiation of the donor is changed significantly less because this inner disk region (which emits beyond the ASM band and acts as the occulting region of the beams) also irradiates the donor.

  19. The pure rotational spectrum of ZnS (X 1Σ +)

    Science.gov (United States)

    Zack, L. N.; Ziurys, L. M.

    2009-10-01

    The pure rotational spectrum of ZnS (X 1Σ +) has been measured using direct-absorption millimeter/sub-millimeter techniques in the frequency range 372-471 GHz. This study is the first spectroscopic investigation of this molecule. Spectra originating in four zinc isotopologues ( 64ZnS, 66ZnS, 68ZnS, and 67ZnS) were recorded in natural abundance in the ground vibrational state, and data from the v = 1 state were also measured for the two most abundant zinc species. Spectroscopic constants have been subsequently determined, and equilibrium parameters have been estimated. The equilibrium bond length was calculated to be re ˜ 2.0464 Å, which agrees well with theoretical predictions. In contrast, the dissociation energy of DE ˜ 3.12 eV calculated for ZnS, assuming a Morse potential, was significantly higher than past experimental and theoretical estimates, suggesting diabatic interaction with other potentials that lower the effective dissociation energy. Although ZnS is isovalent with ZnO, there appear to be subtle differences in bonding between the two species, as suggested by their respective force constants and bond length trends in the 3d series.

  20. Investigation of split-off dimers on the Si(001)2x1 surface

    International Nuclear Information System (INIS)

    Schofield, S.R.; O'Brien, J.L.; Curson, N.J.; Simmons, M.Y.; Clark, R.G.

    2002-01-01

    Full text: A detailed knowledge of the nature of crystalline defects on the Si(001)2x1 surface is becoming increasingly important as more research effort is dedicated to producing atomic-scale electronic devices. Here we present high-resolution scanning tunnelling microscopy (STM) images and ab initio pseudopotential calculations of an unusual defect of the silicon (001) surface called the split-off dimer. In high-resolution filled-state images, split-off dimers appear as a pair of protrusions, in contrast to the surrounding surface dimers that appear as 'bean-shaped' protrusions. We show that π-bonding does not exist between the atoms of the split-off dimer, but instead, the dimer atoms form π-bonds with two second layer atoms as part of a tetramer bonding arrangement. We discuss the strain associated with split-off dimer defects and describe how this strain significantly affects the bonding arrangements and local density of states around these defects

  1. American X-Vehicles: An Inventory X-1 to X-50 Centennial of Flight Edition

    Science.gov (United States)

    Jenkins, Dennis R.; Landis, Tony; Miller, Jay

    2003-01-01

    For a while, it seemed the series of experimental aircraft sponsored by the U. S. government had run its course. Between the late 1940s and the late 1970s, almost thirty designations had been allocated to aircraft meant to explore new flight regimes or untried technologies. Then, largely, it ended. But there was a resurgence in the mid- to late- 1990s, and as we enter the fourth year of the new millennia, the designations are up to x-50. Many have a misconception that X-vehicles have always explored the high-speed and high-altitude flight regimes - something popularized by Chuck Yeager in the original X-1 and the exploits of the twelve men that flew the X-15. Although these flight regimes have always been in the spotlight, many others have been explored by X-vehicles. The little Bensen X-25 never exceeded 85 mph, and others were limited to speeds of several hundred mph. There has been some criticism that the use of X designations has been corrupted somewhat by including what are essentially prototypes of future operational aircraft, especially the two JSF demonstrators. But this is not new-the X-11 and X-12 from the 1950s were going to be prototypes of the Atlas intercontinental ballistic missile, and the still-born Lockheed X-27 was always intended as a prototype of a production aircraft. So although this practice does not represent the best use of 'X' designations, it is not without precedent.

  2. All-fiber 7x1 signal combiner for incoherent laser beam combining

    Science.gov (United States)

    Noordegraaf, D.; Maack, M. D.; Skovgaard, P. M. W.; Johansen, J.; Becker, F.; Belke, S.; Blomqvist, M.; Laegsgaard, J.

    2011-02-01

    We demonstrate an all-fiber 7x1 signal combiner for incoherent laser beam combining. This is a potential key component for reaching several kW of stabile laser output power. The combiner couples the output from 7 single-mode (SM) fiber lasers into a single multi-mode (MM) fiber. The input signal fibers have a core diameter of 17 μm and the output MM fiber has a core diameter of 100 μm. In a tapered section light gradually leaks out of the SM fibers and is captured by a surrounding fluorine-doped cladding. The combiner is tested up to 2.5 kW of combined output power and only a minor increase in device temperature is observed. At an intermediate power level of 600 W a beam parameter product (BPP) of 2.22 mm x mrad is measured, corresponding to an M2 value of 6.5. These values are approaching the theoretical limit dictated by brightness conservation.

  3. INITIATION PROCESSES FOR THE 2013 MAY 13 X1.7 LIMB FLARE

    International Nuclear Information System (INIS)

    Shen, Jinhua; Wang, Ya; Zhou, Tuanhui; Ji, Haisheng

    2017-01-01

    For the X1.7 class flare on 2013 May 13 (SOL2013-05-13T01:53), its initiation process was well observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory and the Extreme UltraViolet Imager (EUVI) on board STEREO-B . The initiation process incorporates the following phenomena: an X-ray precursor that started ∼9 minutes before flare onset, two hot magnetic loops (as seen with AIA hot channels) forming a sigmoidal core magnetic structure (as seen with the EUVI), a rapidly formed magnetic flux rope (MFR) that expands outward, and a flare loop that contracts inward. The two hot magnetic loops were activated after the occurrence of the X-ray precursor. After activation, magnetic reconnection occurred between the two hot magnetic loops (inside the sigmoid structure), which produced the expanding MFR and the contracting flare loop (CFL). The MFR and CFL can only be seen with AIA hot and cool channels, respectively. For this flare, the real initiation time can be regarded as being from the starting time of the precursor, and its impulsive phase started when the MFR began its fast expansion. In addition, the CFL and the growing postflare magnetic loops are different loop systems, and the CFL was the product of magnetic reconnection between sheared magnetic fields that also produced the MFR.

  4. INITIATION PROCESSES FOR THE 2013 MAY 13 X1.7 LIMB FLARE

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Jinhua [Xinjiang Astronomical Observatory, CAS, 830011, Urumqi (China); Wang, Ya; Zhou, Tuanhui; Ji, Haisheng, E-mail: jihs@pmo.ac.cn [Purple Mountain Observatory, CAS, Nanjing, 210008 (China)

    2017-01-20

    For the X1.7 class flare on 2013 May 13 (SOL2013-05-13T01:53), its initiation process was well observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory and the Extreme UltraViolet Imager (EUVI) on board STEREO-B . The initiation process incorporates the following phenomena: an X-ray precursor that started ∼9 minutes before flare onset, two hot magnetic loops (as seen with AIA hot channels) forming a sigmoidal core magnetic structure (as seen with the EUVI), a rapidly formed magnetic flux rope (MFR) that expands outward, and a flare loop that contracts inward. The two hot magnetic loops were activated after the occurrence of the X-ray precursor. After activation, magnetic reconnection occurred between the two hot magnetic loops (inside the sigmoid structure), which produced the expanding MFR and the contracting flare loop (CFL). The MFR and CFL can only be seen with AIA hot and cool channels, respectively. For this flare, the real initiation time can be regarded as being from the starting time of the precursor, and its impulsive phase started when the MFR began its fast expansion. In addition, the CFL and the growing postflare magnetic loops are different loop systems, and the CFL was the product of magnetic reconnection between sheared magnetic fields that also produced the MFR.

  5. Theoretical studies of binaries in astrophysics

    Science.gov (United States)

    Dischler, Johann Sebastian

    This thesis introduces and summarizes four papers dealing with computer simulations of astrophysical processes involving binaries. The first part gives the rational and theoretical background to these papers. In paper I and II a statistical approach to studying eclipsing binaries is described. By using population synthesis models for binaries the probabilities for eclipses are calculated for different luminosity classes of binaries. These are compared with Hipparcos data and they agree well if one uses a standard input distribution for the orbit sizes. If one uses a random pairing model, where both companions are independently picked from an IMF, one finds too feclipsing binaries by an order of magnitude. In paper III we investigate a possible scenario for the origin of the stars observed close to the centre of our galaxy, called S stars. We propose that a cluster falls radially cowards the central black hole. The binaries within the cluster can then, if they have small impact parameters, be broken up by the black hole's tidal held and one of the components of the binary will be captured by the black hole. Paper IV investigates how the onset of mass transfer in eccentric binaries depends on the eccentricity. To do this we have developed a new two-phase SPH scheme where very light particles are at tire outer edge of our simulated star. This enables us to get a much better resolution of the very small mass that is transferred in close binaries. Our simulations show that the minimum required distance between the stars to have mass transfer decreases with the eccentricity.

  6. Binary neutron star merger simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bruegmann, Bernd [Jena Univ. (Germany)

    2016-11-01

    Our research focuses on the numerical tools necessary to solve Einstein's equations. In recent years we have been particularly interested in spacetimes consisting of two neutron stars in the final stages of their evolution. Because of the emission of gravitational radiation, the objects are driven together to merge; the emitted gravitational wave signal is visualized. This emitted gravitational radiation carries energy and momentum away from the system and contains information about the system. Late last year the Laser Interferometer Gravitational-wave Observatory (LIGO) began searches for these gravitational wave signals at a sensitivity at which detections are expected. Although such systems can radiate a significant amount of their total mass-energy in gravitational waves, the gravitational wave signals one expects to receive on Earth are not strong, since sources of gravitational waves are often many millions of light years away. Therefore one needs accurate templates for the radiation one expects from such systems in order to be able to extract them out of the detector's noise. Although analytical models exist for compact binary systems when the constituents are well separated, we need numerical simulation to investigate the last orbits before merger to obtain accurate templates and validate analytical approximations. Due to the strong nonlinearity of the equations and the large separation of length scales, these simulations are computationally demanding and need to be run on large supercomputers. When matter is present the computational cost as compared to pure black hole (vacuum) simulations increases even more due to the additional matter fields. But also more interesting astrophysical phenomena can happen. In fact, there is the possibility for a strong electromagnetic signal from the merger (e.g., a short gamma-ray burst or lower-energy electromagnetic signatures from the ejecta) and significant neutrino emission. Additionally, we can expect that

  7. Instabilities in Interacting Binary Stars

    Science.gov (United States)

    Andronov, I. L.; Andrych, K. D.; Antoniuk, K. A.; Baklanov, A. V.; Beringer, P.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Cook, L. M.; Cook, M.; Dubovský, P.; Godlowski, W.; Hegedüs, T.; Hoňková, K.; Hric, L.; Jeon, Y.-B.; Juryšek, J.; Kim, C.-H.; Kim, Y.; Kim, Y.-H.; Kolesnikov, S. V.; Kudashkina, L. S.; Kusakin, A. V.; Marsakova, V. I.; Mason, P. A.; Mašek, M.; Mishevskiy, N.; Nelson, R. H.; Oksanen, A.; Parimucha, S.; Park, J.-W.; Petrík, K.; Quiñones, C.; Reinsch, K.; Robertson, J. W.; Sergey, I. M.; Szpanko, M.; Tkachenko, M. G.; Tkachuk, L. G.; Traulsen, I.; Tremko, J.; Tsehmeystrenko, V. S.; Yoon, J.-N.; Zola, S.; Shakhovskoy, N. M.

    2017-07-01

    The types of instability in the interacting binary stars are briefly reviewed. The project “Inter-Longitude Astronomy” is a series of smaller projects on concrete stars or groups of stars. It has no special funds, and is supported from resources and grants of participating organizations, when informal working groups are created. This “ILA” project is in some kind similar and complementary to other projects like WET, CBA, UkrVO, VSOLJ, BRNO, MEDUZA, AstroStatistics, where many of us collaborate. Totally we studied 1900+ variable stars of different types, including newly discovered variables. The characteristic timescale is from seconds to decades and (extrapolating) even more. The monitoring of the first star of our sample AM Her was initiated by Prof. V.P. Tsesevich (1907-1983). Since more than 358 ADS papers were published. In this short review, we present some highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types: classical (AM Her, QQ Vul, V808 Aur = CSS 081231:071126+440405, FL Cet), asynchronous (BY Cam, V1432 Aql), intermediate (V405 Aql, BG CMi, MU Cam, V1343 Her, FO Aqr, AO Psc, RXJ 2123, 2133, 0636, 0704) polars and magnetic dwarf novae (DO Dra) with 25 timescales corresponding to different physical mechanisms and their combinations (part “Polar”); negative and positive superhumpers in nova-like (TT Ari, MV Lyr, V603 Aql, V795 Her) and many dwarf novae stars (“Superhumper”); eclipsing “non-magnetic” cataclysmic variables(BH Lyn, DW UMa, EM Cyg; PX And); symbiotic systems (“Symbiosis”); super-soft sources (SSS, QR And); spotted (and not spotted) eclipsing variables with (and without) evidence for a current mass transfer (“Eclipser”) with a special emphasis on systems with a direct impact of the stream into the gainer star's atmosphere, which we propose to call “Impactor” (short from “Extreme Direct Impactor”), or V361 Lyr-type stars. Other

  8. Variance in binary stellar population synthesis

    Science.gov (United States)

    Breivik, Katelyn; Larson, Shane L.

    2016-03-01

    In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.

  9. Proposed experiment to test fundamentally binary theories

    Science.gov (United States)

    Kleinmann, Matthias; Vértesi, Tamás; Cabello, Adán

    2017-09-01

    Fundamentally binary theories are nonsignaling theories in which measurements of many outcomes are constructed by selecting from binary measurements. They constitute a sensible alternative to quantum theory and have never been directly falsified by any experiment. Here we show that fundamentally binary theories are experimentally testable with current technology. For that, we identify a feasible Bell-type experiment on pairs of entangled qutrits. In addition, we prove that, for any n , quantum n -ary correlations are not fundamentally (n -1 ) -ary. For that, we introduce a family of inequalities that hold for fundamentally (n -1 ) -ary theories but are violated by quantum n -ary correlations.

  10. Galactic binaries with eLISA

    OpenAIRE

    Nelemans, G.

    2013-01-01

    I review what eLISA will see from Galactic binaries -- double stars with orbital periods less than a few hours and white dwarf (or neutron star/black hole) components. I discuss the currently known binaries that are guaranteed (or verification) sources and explain why the expected total number of eLISA Galactic binaries is several thousand, even though there are large uncertainties in our knowledge of this population, in particular that of the interacting AM CVn systems. I very briefly sketch...

  11. Primary orbit and the absorption lines of HDE 226868 (Cygnus X-1)

    International Nuclear Information System (INIS)

    Ninkov, Z.; Walker, G.A.H.; Yang, S.

    1987-01-01

    From Reticon spectra of about 1 A resolution taken between 1980 and 1984, the radial velocity curve of HDE 226868 is found to be characteristic of a single-line spectroscopic binary with K = 75.0 + or - 1.0 km/s and e = 0.0. Combining historical velocities from the literature with present data and applying a period-folding analysis, a period of 5.59964 + or - 0.00001 days is found. These values agree well with those published by Gies and Bolton (1982). The value of v sin i is estimated to be 94.3 + or - 5 km/s from CFHT Reticon spectra taken at 0.1 A resolution. Assuming that the rotation of the primary is synchronized to the orbital revolution of the secondary gives a primary to secondary mass ratio between 1.5 and 2.3. An absolute magnitude of -6.5 + or - 0.2 is derived from the equivalent width of H-gamma (1.5 + or - 0.1 A) and the calibration of Walker and Millward (1985), which is consistent with the spectral classification of O9.7 Iab. Assuming 20 solar masses as a reasonable estimate for the mass of the primary implies a mass of 10 + or - 1 solar masses for the secondary. 62 references

  12. Orbital elements and an analysis of models for HDE 226868 = Cygnus X-1

    International Nuclear Information System (INIS)

    Bolton, C.T.

    1975-01-01

    Radial velocities from 21 new high-dispersion spectrograms of HDE 226868 are presented. These are combined with previously published data to calculate a ''definitive'' set of orbital elements for the binary system. In particular, archival data are used to obtain a precise period. The ellipsoidal light curve is analyzed using both a Roche model and an ellipsoidal model, and the results are compared with work by Hutchings. Information from the absorption-line and emission-line velocity curves and the light curve is combined to give estimates for the orbital inclination and the component masses. The possible errors in the analysis are discussed and are shown to be negligible. A qualitative model for the mass transfer is proposed that explains the intensity and velocity variations of the optical emission lines and the variations in the X-ray intensity: including the low-energy X-ray absorption events sometimes seen near superior conjunction of the secondary. Tests of this model are also proposed. Finally, the observations are used to test various models that have been proposed for the system. The observations rule out low mass and rotating degenerate dwarf secondaries and present difficulties for the triple star model. The magnetic reconnection model is not ruled out by the observations. Models in which the secondary is a black hole are consistent with all available observations

  13. Clumpy wind accretion in Supergiant X-ray Binaries

    Science.gov (United States)

    El Mellah, I.; Sundqvist, J. O.; Keppens, R.

    2017-12-01

    Supergiant X-ray binaries (\\sgx) contain a neutron star (NS) orbiting a Supergiant O/B star. The fraction of the dense and fast line-driven wind from the stellar companion which is accreted by the NS is responsible for most of the X-ray emission from those system. Classic \\sgx display photometric variability of their hard X-ray emission, typically from a few 10^{35} to a few 10^{37}erg\\cdots^{-1}. Inhomogeneities (\\aka clumps) in the wind from the star are expected to play a role in this time variability. We run 3D hydrodynamical (HD) finite volume simulations to follow the accretion of the inhomogeneous stellar wind by the NS over almost 3 orders of magnitude. To model the unperturbed wind far upstream the NS, we use recent simulations which managed to resolve its micro-structure. We observe the formation of a Bondi-Hoyle-Lyttleton (BHL) like bow shock around the accretor and follow the clumps as they cross it, down to the NS magnetosphere. Compared to previous estimations discarding the HD effects, we measure lower time variability due to both the damping effect of the shock and the necessity to evacuate angular momentum to enable accretion. We also compute the associated time-variable column density and compare it to recent observations in Vela X-1.

  14. Dixie Valley Bottoming Binary Unit

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, Dale [Terra-Gen Sierra Holdings, LLC, Reno, NV (United States)

    2014-12-21

    This binary plant is the first air cooled, high-output refrigeration based waste heat recovery cycle in the industry. Its working fluid is environmentally friendly and as such, the permits that would be required with a hydrocarbon based cycle are not necessary. The unit is largely modularized, meaning that the unit’s individual skids were assembled in another location and were shipped via truck to the plant site. The Air Cooled Condensers (ACC), equipment piping, and Balance of Plant (BOP) piping were constructed at site. This project further demonstrates the technical feasibility of using low temperature brine for geothermal power utilization. The development of the unit led to the realization of low temperature, high output, and environmentally friendly heat recovery systems through domestic research and engineering. The project generates additional renewable energy, resulting in cleaner air and reduced carbon dioxide emissions. Royalty and tax payments to governmental agencies will increase, resulting in reduced financial pressure on local entities. The major components of the unit were sourced from American companies, resulting in increased economic activity throughout the country.

  15. The symbiotics as binary stars

    International Nuclear Information System (INIS)

    Plavec, M.J.

    1982-01-01

    The author envisages at least three models that can give a symbiotic object: He has called them, respectively, the PN symbiotic, the Algol symbiotic, and the novalike symbiotic. Their properties are briefly discussed. The most promising model is one of a binary system in the second stage of mass transfer, actually at the beginning of it: The cool component is a red giant ascending the asymptotic branch, expanding but not yet filling its critical lobe. The hot star is a subdwarf located in the same region of the Hertzsprung-Russell diagram as the central stars of planetary nebulae. It may be closely related to them, or it may be a helium star, actually a remnant of an Algol primary which underwent the first stage of mass transfer. In these cases, accretion on this star may not play a significant role (PN symbiotic). Perhaps more often, the subdwarf is a ''rejuvenated'' degenerate dwarf whose nuclear burning shells were ignited and are maintained by accretion of material coming from the red giant in the form of a stellar wind. Eruptions are often inevitable: this is the novalike symbiotic. A third alternative is a system in the first stage of mass transfer, where the photons needed for ionization of the nebula come from an accretion disk surrounding a main sequence star: an Algol symbiotic. In spite of considerable observational effort, the symbiotics are known so poorly that it is hard to decide between the models, or even decide if all three can actually exist. (Auth.)

  16. Pulsars in binary systems: probing binary stellar evolution and general relativity.

    Science.gov (United States)

    Stairs, Ingrid H

    2004-04-23

    Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.

  17. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    International Nuclear Information System (INIS)

    Haghighipour, Nader; Kaltenegger, Lisa

    2013-01-01

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results

  18. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Kaltenegger, Lisa [MPIA, Koenigstuhl 17, Heidelberg, D-69117 (Germany)

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  19. A new species of Endecous Saussure, 1878 (Orthoptera, Gryllidae) from northeast Brazil with the first X1X20 chromosomal sex system in Gryllidae.

    Science.gov (United States)

    Zefa, Edison; Redü, Darlan Rutz; Da Costa, Maria Kátia Matiotti; Fontanetti, Carmem S; Gottschalk, Marco Silva; Padilha, Giovanna Boff; Fernandes e Silva, Anelise; Martins, Luciano De P

    2014-08-06

    In this paper we describe a new species of Luzarinae cricket collected from the cave "Gruta de Ubajara, municipality of Ubajara, State of Ceará, Brazil, highlighting phallic sclerites morphology and chromosome complement as diagnostic characters. We presented meiotic and mitotic characterization in order to define the karyotype with 2n = 12 + X1X2♂/12 + X1X1X2X2♀. This represents the first record of X1X20 chromosomal sex system in Gryllidae.

  20. On the origin of a sunquake during the 2014 March 29 X1 flare

    Energy Technology Data Exchange (ETDEWEB)

    Judge, Philip G. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States); Kleint, Lucia [Institute of 4D Technologies, University of Applied Sciences and Arts Northwestern Switzerland, 5210 Windisch (Switzerland); Donea, Alina [Center for Astrophysics, School of Mathematical Science, Monash University, Victoria 3800 (Australia); Dalda, Alberto Sainz [Stanford-Lockheed Institute for Space Research, Stanford University, HEPL, 466 Via Ortega, Stanford, CA 94305 (United States); Fletcher, Lyndsay, E-mail: judge@ucar.edu, E-mail: lucia.kleint@fhnw.ch, E-mail: alina.donea@monash.edu, E-mail: asdalda@stanford.edu, E-mail: lyndsay.fletcher@glasgow.ac.uk [SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2014-12-01

    Helioseismic data from the Helioseismic Magnetic Imager instrument have revealed a sunquake associated with the X1 flare SOL2014-03-29T17:48 in active region NOAA 12017. We try to discover if acoustic-like impulses or actions of the Lorentz force caused the sunquake. We analyze spectropolarimetric data obtained with the Facility Infrared Spectrometer (FIRS) at the Dunn Solar Telescope (DST). Fortunately, the FIRS slit crossed the flare kernel close to the acoustic source during the impulsive phase. The infrared FIRS data remain unsaturated throughout the flare. Stokes profiles of lines of Si I 1082.7 nm and He I 1083.0 nm are analyzed. At the flare footpoint, the Si I 1082.7 nm core intensity increases by a factor of several, and the IR continuum increases by 4% ± 1%. Remarkably, the Si I core resembles the classical Ca II K line's self-reversed profile. With nLTE radiative models of H, C, Si, and Fe, these properties set the penetration depth of flare heating to 100 ± 100 km (i.e., photospheric layers). Estimates of the non-magnetic energy flux are at least a factor of two less than the sunquake energy flux. Milne-Eddington inversions of the Si I line show that the local magnetic energy changes are also too small to drive the acoustic pulse. Our work raises several questions. Have we missed the signature of downward energy propagation? Is it intermittent in time and/or non-local? Does the 1-2 s photospheric radiative damping time discount compressive modes?.

  1. AstroSat /LAXPC Observation of Cygnus X-1 in the Hard State

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Ranjeev; Pahari, Mayukh [Inter-University Centre for Astronomy and Astrophysics, Pune 411007 (India); Yadav, J S; Chauhan, Jai Verdhan; Antia, H M; Chitnis, V R; Dedhia, Dhiraj; Katoch, Tilak; Madhwani, P.; Shah, Parag [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai (India); Agrawal, P C [UM-DAE Center of Excellence for Basic Sciences, University of Mumbai, Kalina, Mumbai-400098 (India); Manchanda, R K [University of Mumbai, Kalina, Mumbai-400098 (India); Paul, B, E-mail: rmisra@iucaa.in [Dept. of Astronomy and Astrophysics, Raman Research Institute, Bengaluru-560080 (India)

    2017-02-01

    We report the first analysis of data from AstroSat /LAXPC observations of Cygnus X-1 in 2016 January. LAXPC spectra reveals that the source was in the canonical hard state, represented by a prominent thermal Comptonization component having a photon index of ∼1.8 and high temperature of kT{sub e} > 60 keV along with weak reflection and possible disk emission. The power spectrum can be characterized by two broad lorentzian functions centered at ∼0.4 and ∼3 Hz. The rms of the low-frequency component decreases from ∼15% at around 4 keV to ∼10% at around 50 keV, while that of the high-frequency one varies less rapidly from ∼13.5% to ∼11.5% in the same energy range. The time lag between the hard (20–40 keV) and soft (5–10 keV) bands varies in a step-like manner being nearly constant at ∼50 milliseconds from 0.3 to 0.9 Hz, decreasing to ∼8 milliseconds from 2 to 5 Hz and finally dropping to ∼2 milliseconds for higher frequencies. The time lags increase with energy for both the low and high-frequency components. The event mode LAXPC data allows for flux resolved spectral analysis on a timescale of 1 s, which clearly shows that the photon index increased from ∼1.72 to ∼1.80 as the flux increased by nearly a factor of two. We discuss the results in the framework of the fluctuation propagation model.

  2. General simulation algorithm for autocorrelated binary processes.

    Science.gov (United States)

    Serinaldi, Francesco; Lombardo, Federico

    2017-02-01

    The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

  3. General simulation algorithm for autocorrelated binary processes

    Science.gov (United States)

    Serinaldi, Francesco; Lombardo, Federico

    2017-02-01

    The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

  4. Observations of new Wolf-Rayet binaries

    International Nuclear Information System (INIS)

    Niemela, V.S.

    1982-01-01

    The author reports here preliminary results of spectrographic observations for three southern WR stars, whose binary nature had not been previously verified: HDE 320102, CD -45 0 4482, HD 62910. The observations were carried out at the Cerro Tololo Inter-American Observatory, Chile, mostly with the Cassegrain spectrograph with IT attached to the 1-m reflector. These spectrograms were secured on Kodak IIIaJ emulsion, and have a dispersion of 45 A/mm. The results suggest that HDE 320102 must be a double-lined 05-7 + WN3 spectroscopic binary, that CD -45 0 4482 appears to be a single-lined spectroscopic binary and that HD 62910 may be a binary. (Auth.)

  5. A PROPELLER-EFFECT INTERPRETATION OF MAXI/GSC LIGHT CURVES OF 4U 1608-52 AND Aql X-1 AND APPLICATION TO XTE J1701-462

    Energy Technology Data Exchange (ETDEWEB)

    Asai, K.; Matsuoka, M.; Mihara, T.; Sugizaki, M.; Serino, M. [MAXI Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nakahira, S. [ISS Science Project Office, ISAS, JAXA, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan); Negoro, H. [Department of Physics, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Ueda, Y. [Department of Astronomy, Kyoto University, Kitashirakawa, Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Yamaoka, K., E-mail: kazumi@crab.riken.jp [Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

    2013-08-20

    We present the luminosity dwell-time distributions during the hard states of two low-mass X-ray binaries containing a neutron star (NS), 4U 1608-52 and Aql X-1, observed with MAXI/GSC. The luminosity distributions show a steep cutoff on the low-luminosity side at {approx}1.0 Multiplication-Sign 10{sup 36} erg s{sup -1} in both sources. The cutoff implies a rapid luminosity decrease in their outburst decay phases and this decrease can be interpreted as being due to the propeller effect. We estimate the surface magnetic field of 4U 1608-52 to be (0.5-1.6) Multiplication-Sign 10{sup 8} G and Aql X-1 to be (0.6-1.9) Multiplication-Sign 10{sup 8} G from the cutoff luminosity and apply the same propeller mechanism to the similar rapid luminosity decrease observed in the transient Z source, XTE J1701-462, with RXTE/ASM. Assuming that the spin period of the NS is on the order of milliseconds, the observed cutoff luminosity implies a surface magnetic field on the order of 10{sup 9} G.

  6. Diffusion in ordered binary solid systems

    International Nuclear Information System (INIS)

    Stolwijk, N.A.

    1980-01-01

    This thesis contains contributions to the field of diffusion in ordered binary solid systems. An extensive experimental investigation of the self diffusion in CoGa is presented. The results of these diffusion measurements strongly suggest that a substantial part of the atomic migration is caused by a new type of defect. A quantitative description of the atomic displacements via this defect is given. Finally computer simulations are presented of diffusion and ordering in binary solid systems. (Auth.)

  7. An Introduction to Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Andersen, Henrik Reif

    1996-01-01

    This note is a short introduction to Binary Decision Diagrams (BDDs). It provides some background knowledge and describes the core algorithms. It is used in the course "C4340 Advanced Algorithms" at the Technical University of Denmark, autumn 1996.......This note is a short introduction to Binary Decision Diagrams (BDDs). It provides some background knowledge and describes the core algorithms. It is used in the course "C4340 Advanced Algorithms" at the Technical University of Denmark, autumn 1996....

  8. Roche-Lobe overflow in X-ray binaries, ch. 2

    International Nuclear Information System (INIS)

    Savonije, G.J.

    1977-01-01

    It is examined whether Roche-lobe overflow can be the main mechanism of mass transfer that powers the low-mass as well as the massive X-ray binaries. Detailed numerical computations of the initial phase of Roche-lobe overflow were performed in order to determine the precise time development of the mass transfer from normal stars with masses ranging from 1.5 M(sun) up to 20 M(sun) to compact companions with masses of 1 and 1.5 M(sun). The binary code includes a simplified hydrodynamical treatment of Roche-lobe overflow. For massive primaries this hydrodynamical treatment appears to result in much longer X-ray lifetimes than obtained in previous investigations. The calculations also include effects of slow, non-synchronous rotation of the contact star and loss of mass and angular momentum from the binary system. For Her X-1 and Cen X-3 X-ray lifetimes of the order of 10 5 and 10 4 yrs are predicted, respectively

  9. Enhanced winds and tidal streams in massive X-ray binaries

    International Nuclear Information System (INIS)

    Blondin, J.M.; Stevens, I.R.; Kallman, T.R.

    1991-01-01

    The tidal effects created by the presence of a compact companion are expected to induce a stream of enhanced wind from the early-type primary star in massive X-ray binary systems. In this paper, two-dimensional gasdynamical simulations of such streams are presented. It is found that the wind enhancement is a sensitive function of the binary separation, and develops into a tidal stream as the primary approaches its critical surface. For typical system parameters, the Coriolis force deflects the stream sufficiently that it does not impact directly on the compact companion but passes behind it. The density in the stream can reach values of 20-30 times the ambient wind density, leading to strong attenuation of the X-ray flux that passes through the tidal stream, providing a possible explanation of the enhanced absorption events seen at later phases in the X-ray observations of massive X-ray binary systems such as Vela X-1. In contrast to the time-variable accretion wake, the tidal stream is relatively stationary, producing absorption features that should remain fixed from orbit to orbit. For systems with a strong tidal stream, the large asymmetry in the accreting wind results in the accretion of angular momentum of constant sign, as opposed to systems without streams, where the sign of the accreted angular momentum can change. 39 refs

  10. Asteroseismic effects in close binary stars

    Science.gov (United States)

    Springer, Ofer M.; Shaviv, Nir J.

    2013-09-01

    Turbulent processes in the convective envelopes of the Sun and stars have been shown to be a source of internal acoustic excitations. In single stars, acoustic waves having frequencies below a certain cut-off frequency propagate nearly adiabatically and are effectively trapped below the photosphere where they are internally reflected. This reflection essentially occurs where the local wavelength becomes comparable to the pressure scale height. In close binary stars, the sound speed is a constant on equipotentials, while the pressure scale height, which depends on the local effective gravity, varies on equipotentials and may be much greater near the inner Lagrangian point (L1). As a result, waves reaching the vicinity of L1 may propagate unimpeded into low-density regions, where they tend to dissipate quickly due to non-linear and radiative effects. We study the three-dimensional propagation and enhanced damping of such waves inside a set of close binary stellar models using a WKB approximation of the acoustic field. We find that these waves can have much higher damping rates in close binaries, compared to their non-binary counterparts. We also find that the relative distribution of acoustic energy density at the visible surface of close binaries develops a ring-like feature at specific acoustic frequencies and binary separations.

  11. Texture classification by texton: statistical versus binary.

    Directory of Open Access Journals (Sweden)

    Zhenhua Guo

    Full Text Available Using statistical textons for texture classification has shown great success recently. The maximal response 8 (Statistical_MR8, image patch (Statistical_Joint and locally invariant fractal (Statistical_Fractal are typical statistical texton algorithms and state-of-the-art texture classification methods. However, there are two limitations when using these methods. First, it needs a training stage to build a texton library, thus the recognition accuracy will be highly depended on the training samples; second, during feature extraction, local feature is assigned to a texton by searching for the nearest texton in the whole library, which is time consuming when the library size is big and the dimension of feature is high. To address the above two issues, in this paper, three binary texton counterpart methods were proposed, Binary_MR8, Binary_Joint, and Binary_Fractal. These methods do not require any training step but encode local feature into binary representation directly. The experimental results on the CUReT, UIUC and KTH-TIPS databases show that binary texton could get sound results with fast feature extraction, especially when the image size is not big and the quality of image is not poor.

  12. Origin of very-short orbital-period binary systems

    International Nuclear Information System (INIS)

    Miyaji, S.

    1983-01-01

    Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both X-ray close binaries and cataclysmic variables. Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of which belongs to any globular cluster, are too abundant to be explained by the capturing mechanism of a white dwarf. Therefore it seemed to be worthwhile to present an evolutionary scenario from an original binary system which can be applied for all VSOP binaries. (Auth.)

  13. Gas dynamics of semidetached binaries

    International Nuclear Information System (INIS)

    Lubow, S.H.; Shu, F.H.

    1975-01-01

    We analyze the gas dynamics of semidetached binary systems within the context of the Rohce model. With the adoption of the assumptions that the contact component rotates synchronously and that the flow occurs isothermally with the thermal speed being a small fraction epsilon of the relative orbital speed, Ωd, of the two stars, we show that the steady flow can be formulated in terms of a problem with multiple length scales. Using this concept, we demonstrate the following by semianalytical methods. (1) The escape of material from the surface of the contact component is accomplished by a highly nonisotropic stellar wind which reaches sonic velocities in a neighborhood of the inner Lagrangian point, L1, of size epsilon in comparison with the orbit separation d. (2) This wind throttles into a narrow stram of material which makes a prescribed angle with respect to the line joining the stellar centers ranging from 19 0 5 to 28 0 4 for the full range of possible stellar mass ratios. (3) The width of the stream scales epsilond while its density scales with epsilon -2 M-dot/Ωd 3 , where M-dot is the mass transfer rate. (4) The stream width remains nearly constant over the part of the stream which is nearly straight, and narrows somewhat as the stream curves toward the detached component. (5) If the detached component is smaller than a certain specified size, the stream results in the formation of a disk of material of prescribed size orbiting the detached component in a direct sense. A subsidi []ry issue examined briefly in this paper is the flow mechanism responsible for moving material to the equator of the contact component, and from there to the L1 region where it is lost by the directed stellar wind. Comparisons of our work are made with previous theoretical studies, and some applications are indicated

  14. Understanding the Long-Term Spectral Variability of Cygnus X-1 from BATSE and ASM Observations

    Science.gov (United States)

    Zdziarski, Andrzej A.; Poutanen, Juri; Paciesas, William S.; Wen, Linqing; Six, N. Frank (Technical Monitor)

    2002-01-01

    We present a spectral analysis of observations of Cygnus X-1 by the RXTE/ASM (1.5-12 keV) and CGRO/BATSE (20-300 keV), including about 1200 days of simultaneous data. We find a number of correlations between intensities and hardnesses in different energy bands from 1.5 keV to 300 keV. In the hard (low) spectral state, there is a negative correlation between the ASM 1.5-12 keV flux and the hardness at any energy. In the soft (high) spectral state, the ASM flux is positively correlated with the ASM hardness (as previously reported) but uncorrelated with the BATSE hardness. In both spectral states, the BATSE hardness correlates with the flux above 100 keV, while it shows no correlation with the flux in the 20-100 keV range. At the same time, there is clear correlation between the BATSE fluxes below and above 100 keV. In the hard state, most of the variability can be explained by softening the overall spectrum with a pivot at approximately 50 keV. The observations show that there has to be another, independent variability pattern of lower amplitude where the spectral shape does not change when the luminosity changes. In the soft state, the variability is mostly caused by a variable hard (Comptonized) spectral component of a constant shape superimposed on a constant soft blackbody component. These variability patterns are in agreement with the dependence of the rms variability on the photon energy in the two states. We interpret the observed correlations in terms of theoretical Comptonization models. In the hard state, the variability appears to be driven mostly by changing flux in seed photons Comptonized in a hot thermal plasma cloud with an approximately constant power supply. In the soft state, the variability is consistent with flares of hybrid, thermal/nonthermal, plasma with variable power above a stable cold disk. Also, based on broadband pointed observations simultaneous with those of the ASM and BATSE, we find the intrinsic bolometric luminosity increases by a

  15. DISAPPEARANCE OF COMET C/2010 X1 (ELENIN): GONE WITH A WHIMPER, NOT A BANG

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing; Jewitt, David, E-mail: jli@igpp.ucla.edu [Department of Earth, Planetary and Space Sciences, University of California at Los Angeles (United States)

    2015-04-15

    We examine the rise and sudden demise of comet C/2010 X1 (Elenin) on its approach to perihelion. Discovered inbound at 4.2 AU, this long-period comet was predicted to become very bright when near perihelion, at 0.48 AU on 2011 September 10. Observations starting 2011 February (heliocentric distance ∼3.5 AU) indeed show the comet to brighten by about 11 mag, with most of the increase occurring inside 1 AU from the Sun. The peak brightness reached m{sub R} = 6 on UT 2011 August 12.95 ± 0.50, when at ∼0.83 AU from the Sun. Thereafter, the comet faded even as the heliocentric distance continued to decrease. We find that most of the surge in brightness in mid-August resulted from dust-particle forward scattering, not from a sudden increase in the activity. A much smaller (∼3 mag) brightening began on UT 2011 August 18 ± 1 (heliocentric distance 0.74 AU), reached a maximum on UT 2011 August 30 ± 1 (at 0.56 AU), and reflects the true breakup of the nucleus. This second peak was matched by a change in the morphology from centrally condensed to diffuse. The estimated cross section of the nucleus when at 1 AU inbound was ∼1 km{sup 2}, corresponding to an equal-area circle of radius 0.6 km. Observations were taken after the second peak using the Canada–France–Hawaii 3.6 m telescope to search for surviving fragments of the nucleus. None were found to a limiting red magnitude r′ = 24.4, corresponding to radii ≲40 m (red geometric albedo = 0.04 assumed). The brightening, the progressive elongation of the debris cloud, and the absence of a central condensation in data taken after UT 2011 August 30 are consistent with disintegration of the nucleus into a power law size distribution of fragments with index q = 3.3 ± 0.2 combined with the action of radiation pressure. In such a distribution, the largest particles contain most of the mass while the smallest particles dominate the scattering cross section and apparent brightness. We speculate about physical

  16. Binaries and triples among asteroid pairs

    Science.gov (United States)

    Pravec, Petr; Scheirich, Peter; Kušnirák, Peter; Hornoch, Kamil; Galád, Adrián

    2015-08-01

    Despite major achievements obtained during the past two decades, our knowledge of the population and properties of small binary and multiple asteroid systems is still far from advanced. There is a numerous indirect evidence for that most small asteroid systems were formed by rotational fission of cohesionless parent asteroids that were spun up to the critical frequency presumably by YORP, but details of the process are lacking. Furthermore, as we proceed with observations of more and more binary and paired asteroids, we reveal new facts that substantially refine and sometimes change our understanding of the asteroid systems. One significant new finding we have recently obtained is that primaries of many asteroid pairs are actually binary or triple systems. The first such case found is (3749) Balam (Vokrouhlický, ApJL 706, L37, 2009). We have found 9 more binary systems among asteroid pairs within our ongoing NEOSource photometric project since October 2012. They are (6369) 1983 UC, (8306) Shoko, (9783) Tensho-kan, (10123) Fideoja, (21436) Chaoyichi, (43008) 1999 UD31, (44620) 1999 RS43, (46829) 1998 OS14 and (80218) 1999 VO123. We will review their characteristics. These paired binaries as we call them are mostly similar to binaries in the general ("background") population (of unpaired asteroids), but there are a few trends. The paired binaries tend to have larger secondaries with D_2/D_1 = 0.3 to 0.5 and they also tend to be wider systems with 8 of the 10 having orbital periods between 30 and 81 hours, than average among binaries in the general population. There may be also a larger fraction of triples; (3749) Balam is a confirmed triple, having a larger close and a smaller distant satellite, and (8306) Shoko and (10123) Fideoja are suspect triples as they show additional rotational lightcurve components with periods of 61 and 38.8 h that differ from the orbital period of 36.2 and 56.5 h, respectively. The unbound secondaries tend to be of the same size or

  17. Close-binary central stars of planetary nebulae

    International Nuclear Information System (INIS)

    Bond, H.E.; Grauer, A.D.

    1987-01-01

    Recent observations of PN central stars identified as binary systems are reviewed. The theoretical significance of binary central stars is discussed, and the characteristics of UU Sge, V 477 Lyr, MT Ser, LSS 2018, VW Pyx, and the central star of HFG 1 are briefly summarized. All of these binaries are shown to have periods less than 1 day, and it is estimated that about 10 percent of all binary central stars are close binaries. 27 references

  18. The Soft State of Cygnus X-1 Observed With NuSTAR: A Variable Corona and a Stable Inner Disk

    DEFF Research Database (Denmark)

    Walton, D. J.; Tomsick, J. A.; Madsen, K. K.

    2016-01-01

    We present a multi-epoch hard X-ray analysis of Cygnus X-1 in its soft state based on four observations with the Nuclear Spectroscopic Telescope Array (NuSTAR). Despite the basic similarity of the observed spectra, there is clear spectral variability between epochs. To investigate this variabilit...

  19. Theoretical study on photon-phonon coupling at (001)-(2 x 1) surfaces of Ge and {alpha}-Sn

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Sanchez, F.L. [Escuela de Ciencias, Universidad Autonoma ' ' Benito Juarez' ' de Oaxaca, Av. Universidad S/N, Ex-Hacienda de Cinco Senores, Ciudad Universitaria, Oaxaca de Juarez, Oax., 68120 (Mexico); Perez-Rodriguez, F. [Instituto de Fisica, Benemerita Universidad Autonoma de Puebla, Apdo. Post. J-48, Puebla, Pue. 72570 (Mexico)

    2011-06-15

    We present a study of the far-infrared reflectance anisotropy spectra for (001) surfaces of Ge and {alpha}-Sn in the (2 x 1) asymmetric dimer geometry, which exhibit a resonance structure associated with the excitation of surface phonon modes. We have employed a theoretical formalism, based on the adiabatic bond-charge model (ABCM), for computing the far-infrared reflectance anisotropy spectra. In comparison with previous theoretical results for silicon and diamond surfaces, the resonance structure in the reflectance anisotropy spectrum for Ge(001)-(2 x 1) turns out to be similar to that observed in the spectrum for the Si(001)-(2 x 1) surface, whereas the spectrum for {alpha}-Sn(001)-(2 x 1) surface is noticeably different from the others. We have established a trend of far-infrared reflectance anisotropy spectra for IV(001) surfaces: the weaker dimer strength, the stronger resonances of low-frequency surface phonons. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Hard x ray observations of Vela X-1 and A0535+26 with HEXE: Discovery of cyclotron lines

    Science.gov (United States)

    Kendziorra, E.; Mony, B.; Kretschmar, P.; Maisack, M.; Staubert, R.; Doebereiner, S.; Englhauser, J.; Pietsch, W.; Reppin, C.; Truemper, J.

    1992-01-01

    The X ray pulsars Vela X-1 (4U 0900-40) and A0535+26) were observed with the High Energy X ray Experiment (HEXE) onboard the Mir space station at energies above 20 keV. The pulse profiles of Vela X-1 (P = 283.22 s for JD 244 7486) and A0535+26 (P = 103.27 s for JD 244 7626) were measured up to at least 100 keV. The time averaged pulse profiles of the two sources both show a clear double peak structure with an asymmetric main pulse and a more symmetric secondary pulse. The spectrum of the main pulse is significantly harder than that of the secondary. Pulse phase resolved spectra show absorption features at 54 keV and possibly 27 keV for Vela X-1 and around 100 keV for A0535+26. If these features are interpreted as second and first harmonic (fundamental) cyclotron absorption lines, lower limits are derived of 2.6 x 10(exp 12) and 4.3 x 10(exp 12) Gauss for the magnetic fields of the neutron stars in Vela X-1 and A0535+26, respectively.

  1. Metal-insulator transition in Si(111)-(4 x 1)/(8 x 2)-In studied by optical spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Speiser, E.; Hinrichs, K.; Cobet, C.; Esser, N. [Leibniz-Institut fuer Analytische Wissenschaften - ISAS - e.V., Albert-Einstein-Str. 9, 12489 Berlin (Germany); Chandola, S. [Leibniz-Institut fuer Analytische Wissenschaften - ISAS - e.V., Albert-Einstein-Str. 9, 12489 Berlin (Germany); School of Physics, Trinity College Dublin 2 (Ireland); Gensch, M. [Helmholtz Zentrum Berlin (Germany); Wippermann, S.; Schmidt, W.G. [Theoretische Physik, Universitaet Paderborn (Germany); Bechstedt, F. [Institut fuer Festkoerpertheorie und -Optik, Friedrich-Schiller-Universitaet, Jena (Germany); Richter, W. [Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Fleischer, K.; McGilp, J.F. [School of Physics, Trinity College Dublin 2 (Ireland)

    2010-08-15

    Measurements of the surface vibrational modes and optical response of Si(111)-(4 x 1)/(8 x 2)-In are compiled and a comparison to ab initio calculations performed within DFT-LDA formalism is given. Surface resonant Raman spectroscopy allows identifying a number of surface phonons with high spectral precision. The phase transition of the (4 x 1)-(8 x 2) surface structure is found to be accompanied by characteristic changes of the surface phonons, which are discussed with respect to various structural models suggested. The optical anisotropy of the (8 x 2) phase shows that the anisotropic Drude tail of the (4 x 1) phase is replaced by two peaks at 0.50 and 0.72 eV. The spectroscopic signatures of the (4 x 1) and (8 x 2) phases agree with a metal-insulator transition. The mid-IR-anisotropic optical response of the insulating (8 x 2) phase is interpreted in terms of electronic single particle excitations between surface electronic bands related to the In-nanowire surface. Comparison of the measured optical transitions with DFT ab initio calculations for the hexagon model and the trimer model of the (8 x 2) structure shows evidence for the existence of the hexagon structure. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. A Semi-analytical Model for Wind-fed Black Hole High-mass X-Ray Binaries: State Transition Triggered by Magnetic Fields from the Companion Star

    Energy Technology Data Exchange (ETDEWEB)

    Yaji, Kentaro; Yamada, Shinya; Masai, Kuniaki [Department of Physics, Tokyo Metropolitan University, Minami-Osawa 1-1, Hachioji, Tokyo 192-0397 (Japan)

    2017-10-01

    We propose a mechanism of state transition in wind-fed black hole (BH) binaries (high-mass X-ray binaries) such as Cyg X-1 and LMC X-1. Modeling a line-driven stellar wind from the companion by two-dimensional hydrodynamical calculations, we investigate the processes of wind capture by, and accretion onto, the BH. We assume that the wind acceleration is terminated at the He ii ionization front because ions responsible for line-driven acceleration are ionized within the front, i.e., the He iii region. It is found that the mass accretion rate inferred from the luminosity is remarkably smaller than the capture rate. Considering the difference, we construct a model for the state transition based on the accretion flow being controlled by magnetorotational instability. The outer flow is torus-like, and plays an important role to trigger the transition. The model can explain why state transition does occur in Cyg X-1, while not in LMC X-1. Cyg X-1 exhibits a relatively low luminosity, and then the He ii ionization front is located and can move between the companion and BH, depending on its ionizing photon flux. On the other hand, LMC X-1 exhibits too high luminosity for the front to move considerably; the front is too close to the companion atmosphere. The model also predicts that each state of high-soft or low-hard would last fairly long because the luminosity depends weakly on the wind velocity. In the context of the model, the state transition is triggered by a fluctuation of the magnetic field when its amplitude becomes comparable to the field strength in the torus-like outer flow.

  3. Energy consumption of ProTaper Next X1 after glide path with PathFiles and ProGlider.

    Science.gov (United States)

    Berutti, Elio; Alovisi, Mario; Pastorelli, Michele Angelo; Chiandussi, Giorgio; Scotti, Nicola; Pasqualini, Damiano

    2014-12-01

    Instrument failure caused by excessive torsional stress can be controlled by creating a manual or mechanical glide path. The ProGlider single-file system (Dentsply Maillefer, Ballaigues, Switzerland) was recently introduced to perform a mechanical glide path. This study was designed to compare the effect of a glide path performed with PathFiles (Dentsply Maillefer) and ProGlider on torque, time, and pecking motion required for ProTaper Next X1 (Dentsply Maillefer) to reach the full working length in simulated root canals. Forty Endo Training Blocks (Dentsply Maillefer) were used. Twenty were prepared with a mechanical glide path using PathFiles 1 and 2 (the PathFile group), and 20 were prepared with a mechanical glide path using a ProGlider single file (the ProGlider group). All samples were shaped with ProTaper Next X1 driven by an endodontic motor connected to a digital wattmeter. The required torque for root canal instrumentation was analyzed by evaluating the electrical power consumption of the endodontic engine. Electric power consumption (mW/h), elapsed time (seconds), and number of pecking motions required to reach the full working length with ProTaper Next X1 were calculated. Differences among groups were analyzed with the parametric Student t test for independent data (P < .05). Elapsed time and electric power consumption were significantly different between groups (P = .0001 for both). ProGlider appears to perform more efficiently than PathFiles in decreasing electric power consumption of ProTaper Next X1 to reach the full working length. This study confirmed the ability of ProGlider to reduce stress in ProTaper Next X1 during shaping through a glide path and preliminary middle and coronal preflaring. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. P2X1 receptors localized in lipid rafts mediate ATP motor responses in the human vas deferens longitudinal muscles.

    Science.gov (United States)

    Donoso, María Verónica; Norambuena, Andrés; Navarrete, Camilo; Poblete, Inés; Velasco, Alfredo; Huidobro-Toro, Juan Pablo

    2014-02-01

    To assess the role of the P2X1 receptors (P2X1R) in the longitudinal and circular layers of the human vas deferens, ex vivo-isolated strips or rings were prepared from tissue biopsies to record isometric contractions. To ascertain its membrane distribution, tissue extracts were analyzed by immunoblotting following sucrose gradient ultracentrifugation. ATP, alpha,beta-methylene ATP, or electrical field stimulation elicited robust contractions of the longitudinal layer but not of the circular layer which demonstrated inconsistent responses. Alpha,beta-methylene ATP generated stronger and more robust contractions than ATP. In parallel, prostatic segments of the rat vas deferens were examined. The motor responses in both species were not sustained but decayed within the first minute, showing desensitization to additional applications. Cross-desensitization was established between alpha,beta-methylene ATP or ATP-evoked contractions and electrical field stimulation-induced contractions. Full recovery of the desensitized motor responses required more than 30 min and showed a similar pattern in human and rat tissues. Immunoblot analysis of the human vas deferens extracts revealed a P2X1R oligomer of approximately 200 kDa under nonreducing conditions, whereas dithiothreitol-treated extracts showed a single band of approximately 70 kDa. The P2X1R was identified in ultracentrifugation fractions containing 15%-29% sucrose; the receptor localized in the same fractions as flotillin-1, indicating that it regionalized into smooth muscle lipid rafts. In conclusion, ATP plays a key role in human vas deferens contractile responses of the longitudinal smooth muscle layer, an effect mediated through P2X1Rs.

  5. Do stellar clusters form fewer binaries? Using moderate separation binaries to distinguish between nature and nurture

    Science.gov (United States)

    Reiter, Megan

    2017-08-01

    Fewer wide-separation binaries are found in dense stellar clusters than in looser stellar associations. It is therefore unclear whether feedback in clusters prevents the formation of multiple systems or dynamical interactions destroy them. Measuring the prevalence of close, bound binary systems provide a key test to distinguish between these possibilities. Systems with separations of 10-50 AU will survive interactions in the cluster environment, and therefore are more representative of the natal population of multiple systems. By fitting a double-star PSF, we will identify visual binaries in the Orion Nebula with separations as small as 0.03. At the distance of Orion, this corresponds to a physical separation of 12 AU, effectively closing the observational gap in the binary separation distribution left between known visual and spectroscopic binaries (>65 AU or PhD thesis.

  6. Serial binary interval ratios improve rhythm reproduction.

    Science.gov (United States)

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  7. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    Xiang eWu

    2013-08-01

    Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  8. Beyond binaries : a way forward for comparativeeducation

    Directory of Open Access Journals (Sweden)

    Marianne Larsen

    2012-09-01

    Full Text Available Binary discourses shape and produce the stories we construct about the field of comparative education. In the first part of this article, I review a set of binary discourses that have characterized social science research since the Enlightenment, including: quantitative-qualitative, nomotheticidiographic, inductive-deductive, and practice-theory. We can think of each of these binaries at opposite ends of a set of spectrums. In the second section of the paper, I show some of the ways in which these binaries have influenced the ways that we write and talk about research within the field of comparative education. I refer to the notion of binary discourses and the productive capacity of these discourses to shape our field. I then outline some critiques of these binaries to demonstrate the inherent limitations of binary discourses, and why we need to move beyond binaries in our research, and in the histories about our field. Finally, I present some tentative conclusions on ways to get ourselves out of the trap of binary thinking.Los discursos binarios moldean y producen los argumentos que construimos sobre la disciplina de la Educación Comparada. En la primera parte de este artículo, analizo un conjunto de discursos binarios que han caracterizado la investigación en Ciencias Sociales desde la Ilustración, incluyendo la cuantitativa-cualitativa, nomotética-idiográfica, inductivadeductiva, y la práctica-teoría. Podemos pensar sobre cada uno de estos discursos binarios como argumentos en los polos de un conjunto de posibilidades. En la segunda sección del artículo, revelo algunos modos en los que estos discursos binarios han influenciado las formas a través de las cuales escribimos y analizamos la investigación en el ámbito de la Educación Comparada. Analizo la noción de discursos binarios y la capacidad productiva de estos discursos de impactar nuestra ciencia. Seguidamente expongo algunas críticas de estos discursos binarios con el

  9. REFINED NEUTRON STAR MASS DETERMINATIONS FOR SIX ECLIPSING X-RAY PULSAR BINARIES

    International Nuclear Information System (INIS)

    Rawls, Meredith L.; Orosz, Jerome A.; McClintock, Jeffrey E.; Torres, Manuel A. P.; Bailyn, Charles D.; Buxton, Michelle M.

    2011-01-01

    We present an improved method for determining the mass of neutron stars in eclipsing X-ray pulsar binaries and apply the method to six systems, namely, Vela X-1, 4U 1538-52, SMC X-1, LMC X-4, Cen X-3, and Her X-1. In previous studies to determine neutron star mass, the X-ray eclipse duration has been approximated analytically by assuming that the companion star is spherical with an effective Roche lobe radius. We use a numerical code based on Roche geometry with various optimizers to analyze the published data for these systems, which we supplement with new spectroscopic and photometric data for 4U 1538-52. This allows us to model the eclipse duration more accurately and thus calculate an improved value for the neutron star mass. The derived neutron star mass also depends on the assumed Roche lobe filling factor β of the companion star, where β = 1 indicates a completely filled Roche lobe. In previous work a range of β between 0.9 and 1.0 was usually adopted. We use optical ellipsoidal light-curve data to constrain β. We find neutron star masses of 1.77 ± 0.08 M sun for Vela X-1, 0.87 ± 0.07 M sun for 4U 1538-52 (eccentric orbit), 1.00 ± 0.10 M sun for 4U 1538-52 (circular orbit), 1.04 ± 0.09 M sun for SMC X-1, 1.29 ± 0.05 M sun for LMC X-4, 1.49 ± 0.08 M sun for Cen X-3, and 1.07 ± 0.36 M sun for Her X-1. We discuss the limits of the approximations that were used to derive the earlier mass determinations, and we comment on the implications our new masses have for observationally refining the upper and lower bounds of the neutron star mass distribution.

  10. Chandra Discovers the X-ray Signature of a Powerful Wind from a Galactic Microquasar

    Science.gov (United States)

    2000-11-01

    NASA's Chandra X-ray Observatory has detected, for the first time in X rays, a stellar fingerprint known as a P Cygni profile--the distinctive spectral signature of a powerful wind produced by an object in space. The discovery reveals a 4.5-million-mile-per-hour wind coming from a highly compact pair of stars in our galaxy, report researchers from Penn State and the Massachusetts Institute of Technology in a paper they will present on 8 November 2000 during a meeting of the High-Energy Astrophysics Division of the American Astronomical Society in Honolulu, Hawaii. The paper also has been accepted for publication in The Astrophysical Journal Letters. "To our knowledge, these are the first P Cygni profiles reported in X rays," say researchers Niel Brandt, assistant professor of astronomy and astrophysics at Penn State, and Norbert S. Schulz, research scientist at the Massachusetts Institute of Technology. The team made the discovery during their first observation of a binary-star system with the Chandra X-ray Observatory, which was launched into space in July 1999. The system, known as Circinus X-1, is located about 20,000 light years from Earth in the constellation Circinus near the Southern Cross. It contains a super-dense neutron star in orbit around a normal fusion-burning star like our Sun. Although Circinus X-1 was discovered in 1971, many properties of this system remain mysterious because Circinus X-1 lies in the galactic plane where obscuring dust and gas have blocked its effective study in many wavelengths. The P Cygni spectral profile, previously detected primarily at ultraviolet and optical wavelengths but never before in X rays, is the textbook tool astronomers rely on for probing stellar winds. The profile looks like the outline of a roller coaster, with one really big hill and valley in the middle, on a data plot with velocity on one axis and the flow rate of photons per second on the other. It is named after the famous star P Cygni, in which such

  11. On the recurrence time and outburst properties of the soft X-ray transient Aquila X-1

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch

    2002-01-01

    Roč. 381, č. 1 (2002), s. 151-167 ISSN 0004-6361 R&D Projects: GA ČR GA205/00/P013 Institutional research plan: CEZ:AV0Z1003909 Keywords : stars activity * stars magnetic fields * close binaries Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.781, year: 2002

  12. The binary white dwarf LHS 3236

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Hugh C.; Dahn, Conard C.; Canzian, Blaise; Guetter, Harry H.; Levine, Stephen E.; Luginbuhl, Christian B.; Monet, Alice K. B.; Stone, Ronald C.; Subasavage, John P.; Tilleman, Trudy; Walker, Richard L. [US Naval Observatory, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Dupuy, Trent J.; Liu, Michael C. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Hartkopf, William I. [US Naval Observatory, 3450 Massachusetts Avenue, N.W., Washington, DC 20392-5420 (United States); Ireland, Michael J. [Department of Physics and Astronomy, Macquarie University, New South Wales, NSW 2109 (Australia); Leggett, S. K., E-mail: hch@nofs.navy.mil [Gemini Observatory, 670 N. Aohoku Place, Hilo, HI 96720 (United States)

    2013-12-10

    The white dwarf LHS 3236 (WD1639+153) is shown to be a double-degenerate binary, with each component having a high mass. Astrometry at the U.S. Naval Observatory gives a parallax and distance of 30.86 ± 0.25 pc and a tangential velocity of 98 km s{sup –1}, and reveals binary orbital motion. The orbital parameters are determined from astrometry of the photocenter over more than three orbits of the 4.0 yr period. High-resolution imaging at the Keck Observatory resolves the pair with a separation of 31 and 124 mas at two epochs. Optical and near-IR photometry give a set of possible binary components. Consistency of all data indicates that the binary is a pair of DA stars with temperatures near 8000 and 7400 K and with masses of 0.93 and 0.91 M {sub ☉}; also possible is a DA primary and a helium DC secondary with temperatures near 8800 and 6000 K and with masses of 0.98 and 0.69 M {sub ☉}. In either case, the cooling ages of the stars are ∼3 Gyr and the total ages are <4 Gyr. The combined mass of the binary (1.66-1.84 M {sub ☉}) is well above the Chandrasekhar limit; however, the timescale for coalescence is long.

  13. Investigating Dark Energy with Black Hole Binaries

    International Nuclear Information System (INIS)

    Mersini-Houghton, Laura; Kelleher, Adam

    2009-01-01

    The accelerated expansion of the universe is ascribed to the existence of dark energy. Black holes accrete dark energy. The accretion induces a mass change proportional to the energy density and pressure of the background dark energy fluid. The time scale during which the mass of black holes changes considerably is long relative to the age of the universe, thus beyond detection possibilities. We propose to take advantage of the modified black hole masses for exploring the equation of state w[z] of dark energy, by investigating the evolution of supermassive black hole binaries on a dark energy background. Deriving the signatures of dark energy accretion on the evolution of binaries, we find that dark energy imprints on the emitted gravitational radiation and on the changes in the orbital radius of the binary can be within detection limits for certain supermassive black hole binaries. This talk describes how binaries can provide a useful tool in obtaining complementary information on the nature of dark energy.

  14. Star formation history: Modeling of visual binaries

    Science.gov (United States)

    Gebrehiwot, Y. M.; Tessema, S. B.; Malkov, O. Yu.; Kovaleva, D. A.; Sytov, A. Yu.; Tutukov, A. V.

    2018-05-01

    Most stars form in binary or multiple systems. Their evolution is defined by masses of components, orbital separation and eccentricity. In order to understand star formation and evolutionary processes, it is vital to find distributions of physical parameters of binaries. We have carried out Monte Carlo simulations in which we simulate different pairing scenarios: random pairing, primary-constrained pairing, split-core pairing, and total and primary pairing in order to get distributions of binaries over physical parameters at birth. Next, for comparison with observations, we account for stellar evolution and selection effects. Brightness, radius, temperature, and other parameters of components are assigned or calculated according to approximate relations for stars in different evolutionary stages (main-sequence stars, red giants, white dwarfs, relativistic objects). Evolutionary stage is defined as a function of system age and component masses. We compare our results with the observed IMF, binarity rate, and binary mass-ratio distributions for field visual binaries to find initial distributions and pairing scenarios that produce observed distributions.

  15. EVOLUTION OF THE BINARY FRACTION IN DENSE STELLAR SYSTEMS

    International Nuclear Information System (INIS)

    Fregeau, John M.; Ivanova, Natalia; Rasio, Frederic A.

    2009-01-01

    Using our recently improved Monte Carlo evolution code, we study the evolution of the binary fraction in globular clusters. In agreement with previous N-body simulations, we find generally that the hard binary fraction in the core tends to increase with time over a range of initial cluster central densities for initial binary fractions ∼<90%. The dominant processes driving the evolution of the core binary fraction are mass segregation of binaries into the cluster core and preferential destruction of binaries there. On a global scale, these effects and the preferential tidal stripping of single stars tend to roughly balance, leading to overall cluster binary fractions that are roughly constant with time. Our findings suggest that the current hard binary fraction near the half-mass radius is a good indicator of the hard primordial binary fraction. However, the relationship between the true binary fraction and the fraction of main-sequence stars in binaries (which is typically what observers measure) is nonlinear and rather complicated. We also consider the importance of soft binaries, which not only modify the evolution of the binary fraction, but can also drastically change the evolution of the cluster as a whole. Finally, we briefly describe the recent addition of single and binary stellar evolution to our cluster evolution code.

  16. Hybrid Black-Hole Binary Initial Data

    Science.gov (United States)

    Mundim, Bruno C.; Kelly, Bernard J.; Nakano, Hiroyuki; Zlochower, Yosef; Campanelli, Manuela

    2010-01-01

    "Traditional black-hole binary puncture initial data is conformally flat. This unphysical assumption is coupled with a lack of radiation signature from the binary's past life. As a result, waveforms extracted from evolutions of this data display an abrupt jump. In Kelly et al. [Class. Quantum Grav. 27:114005 (2010)], a new binary black-hole initial data with radiation contents derived in the post-Newtonian (PN) calculations was adapted to puncture evolutions in numerical relativity. This data satisfies the constraint equations to the 2.5PN order, and contains a transverse-traceless "wavy" metric contribution, violating the standard assumption of conformal flatness. Although the evolution contained less spurious radiation, there were undesired features; the unphysical horizon mass loss and the large initial orbital eccentricity. Introducing a hybrid approach to the initial data evaluation, we significantly reduce these undesired features."

  17. Optimized reversible binary-coded decimal adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert

    2008-01-01

    Abstract Babu and Chowdhury [H.M.H. Babu, A.R. Chowdhury, Design of a compact reversible binary coded decimal adder circuit, Journal of Systems Architecture 52 (5) (2006) 272-282] recently proposed, in this journal, a reversible adder for binary-coded decimals. This paper corrects and optimizes...... their design. The optimized 1-decimal BCD full-adder, a 13 × 13 reversible logic circuit, is faster, and has lower circuit cost and less garbage bits. It can be used to build a fast reversible m-decimal BCD full-adder that has a delay of only m + 17 low-power reversible CMOS gates. For a 32-decimal (128-bit....... Keywords: Reversible logic circuit; Full-adder; Half-adder; Parallel adder; Binary-coded decimal; Application of reversible logic synthesis...

  18. A binary mixture operated heat pump

    International Nuclear Information System (INIS)

    Hihara, E.; Saito, T.

    1991-01-01

    This paper evaluates the performance of possible binary mixtures as working fluids in high- temperature heat pump applications. The binary mixtures, which are potential alternatives of fully halogenated hydrocarbons, include HCFC142b/HCFC22, HFC152a/HCFC22, HFC134a/HCFC22. The performance of the mixtures is estimated by a thermodynamic model and a practical model in which the heat transfer is considered in heat exchangers. One of the advantages of binary mixtures is a higher coefficient of performance, which is caused by the small temperature difference between the heat-sink/-source fluid and the refrigerant. The mixture HCFC142b/HCFC22 is promising from the stand point of thermodynamic performance

  19. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    International Nuclear Information System (INIS)

    Fuller, Jim; Lai Dong

    2012-01-01

    Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10 5 -10 6 years.

  20. Compact binary hashing for music retrieval

    Science.gov (United States)

    Seo, Jin S.

    2014-03-01

    With the huge volume of music clips available for protection, browsing, and indexing, there is an increased attention to retrieve the information contents of the music archives. Music-similarity computation is an essential building block for browsing, retrieval, and indexing of digital music archives. In practice, as the number of songs available for searching and indexing is increased, so the storage cost in retrieval systems is becoming a serious problem. This paper deals with the storage problem by extending the supervector concept with the binary hashing. We utilize the similarity-preserving binary embedding in generating a hash code from the supervector of each music clip. Especially we compare the performance of the various binary hashing methods for music retrieval tasks on the widely-used genre dataset and the in-house singer dataset. Through the evaluation, we find an effective way of generating hash codes for music similarity estimation which improves the retrieval performance.

  1. Reconciliation with non-binary species trees.

    Science.gov (United States)

    Vernot, Benjamin; Stolzer, Maureen; Goldman, Aiton; Durand, Dannie

    2008-10-01

    Reconciliation extracts information from the topological incongruence between gene and species trees to infer duplications and losses in the history of a gene family. The inferred duplication-loss histories provide valuable information for a broad range of biological applications, including ortholog identification, estimating gene duplication times, and rooting and correcting gene trees. While reconciliation for binary trees is a tractable and well studied problem, there are no algorithms for reconciliation with non-binary species trees. Yet a striking proportion of species trees are non-binary. For example, 64% of branch points in the NCBI taxonomy have three or more children. When applied to non-binary species trees, current algorithms overestimate the number of duplications because they cannot distinguish between duplication and incomplete lineage sorting. We present the first algorithms for reconciling binary gene trees with non-binary species trees under a duplication-loss parsimony model. Our algorithms utilize an efficient mapping from gene to species trees to infer the minimum number of duplications in O(|V(G) | x (k(S) + h(S))) time, where |V(G)| is the number of nodes in the gene tree, h(S) is the height of the species tree and k(S) is the size of its largest polytomy. We present a dynamic programming algorithm which also minimizes the total number of losses. Although this algorithm is exponential in the size of the largest polytomy, it performs well in practice for polytomies with outdegree of 12 or less. We also present a heuristic which estimates the minimal number of losses in polynomial time. In empirical tests, this algorithm finds an optimal loss history 99% of the time. Our algorithms have been implemented in NOTUNG, a robust, production quality, tree-fitting program, which provides a graphical user interface for exploratory analysis and also supports automated, high-throughput analysis of large data sets.

  2. Microlensing Binaries Discovered through High-magnification Channel

    DEFF Research Database (Denmark)

    Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.

    2012-01-01

    Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturba......Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010...

  3. Inducing Risk Neutral Preferences with Binary Lotteries

    DEFF Research Database (Denmark)

    Harrison, Glenn W.; Martínez-Correa, Jimmy; Swarthout, J. Todd

    2013-01-01

    validity of any strategic equilibrium behavior, or even the customary independence axiom. We show that subjects sampled from our population are generally risk averse when lotteries are defined over monetary outcomes, and that the binary lottery procedure does indeed induce a statistically significant shift......We evaluate the binary lottery procedure for inducing risk neutral behavior. We strip the experimental implementation down to bare bones, taking care to avoid any potentially confounding assumptions about behavior having to be made. In particular, our evaluation does not rely on the assumed...... toward risk neutrality. This striking result generalizes to the case in which subjects make several lottery choices and one is selected for payment....

  4. A simple model for binary star evolution

    International Nuclear Information System (INIS)

    Whyte, C.A.; Eggleton, P.P.

    1985-01-01

    A simple model for calculating the evolution of binary stars is presented. Detailed stellar evolution calculations of stars undergoing mass and energy transfer at various rates are reported and used to identify the dominant physical processes which determine the type of evolution. These detailed calculations are used to calibrate the simple model and a comparison of calculations using the detailed stellar evolution equations and the simple model is made. Results of the evolution of a few binary systems are reported and compared with previously published calculations using normal stellar evolution programs. (author)

  5. Non-binary or genderqueer genders

    OpenAIRE

    Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John; Nieder, Timo O; T'Sjoen, Guy

    2016-01-01

    Some people have a gender which is neither male nor female and may identify as both male and female at one time, as different genders at different times, as no gender at all, or dispute the very idea of only two genders. The umbrella terms for such genders are genderqueer' or non-binary' genders. Such gender identities outside of the binary of female and male are increasingly being recognized in legal, medical and psychological systems and diagnostic classifications in line with the emerging ...

  6. Applications Of Binary Image Analysis Techniques

    Science.gov (United States)

    Tropf, H.; Enderle, E.; Kammerer, H. P.

    1983-10-01

    After discussing the conditions where binary image analysis techniques can be used, three new applications of the fast binary image analysis system S.A.M. (Sensorsystem for Automation and Measurement) are reported: (1) The human view direction is measured at TV frame rate while the subject's head is free movable. (2) Industrial parts hanging on a moving conveyor are classified prior to spray painting by robot. (3) In automotive wheel assembly, the eccentricity of the wheel is minimized by turning the tyre relative to the rim in order to balance the eccentricity of the components.

  7. Sputtering yield calculation for binary target

    International Nuclear Information System (INIS)

    Jimenez-Rodriguez, J.J.; Rodriguez-Vidal, M.; Valles-Abarca, J.A.

    1979-01-01

    The generalization for binary targets, of the ideas proposed by Sigmund for monoatomic targets, leads to a set of coupled intergrodifferential equations for the sputtering functions. After moment decomposition, the final formulae are obtained by the standard method based on the Laplace Transform, where the inverse transform is made with the aid of asymptotic expansions in the limit of very high projectile energy as compared to the surface binding energy. The possible loss of stoichiometry for binary targets is analyzed. Comparison of computed values of sputtering yield for normal incidence, with experimental results shows good agreement. (author)

  8. Binary Sparse Phase Retrieval via Simulated Annealing

    Directory of Open Access Journals (Sweden)

    Wei Peng

    2016-01-01

    Full Text Available This paper presents the Simulated Annealing Sparse PhAse Recovery (SASPAR algorithm for reconstructing sparse binary signals from their phaseless magnitudes of the Fourier transform. The greedy strategy version is also proposed for a comparison, which is a parameter-free algorithm. Sufficient numeric simulations indicate that our method is quite effective and suggest the binary model is robust. The SASPAR algorithm seems competitive to the existing methods for its efficiency and high recovery rate even with fewer Fourier measurements.

  9. Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

    Science.gov (United States)

    Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

    2017-09-01

    We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

  10. The fate of close encounters between binary stars and binary supermassive black holes

    Science.gov (United States)

    Wang, Yi-Han; Leigh, Nathan; Yuan, Ye-Fei; Perna, Rosalba

    2018-04-01

    The evolution of main-sequence binaries that reside in the Galactic Centre can be heavily influenced by the central supermassive black hole (SMBH). Due to these perturbative effects, the stellar binaries in dense environments are likely to experience mergers, collisions, or ejections through secular and/or non-secular interactions. More direct interactions with the central SMBH are thought to produce hypervelocity stars (HVSs) and tidal disruption events (TDEs). In this paper, we use N-body simulations to study the dynamics of stellar binaries orbiting a central SMBH primary with an outer SMBH secondary orbiting this inner triple. The effects of the secondary SMBH on the event rates of HVSs, TDEs, and stellar mergers are investigated, as a function of the SMBH-SMBH binary mass ratio. Our numerical experiments reveal that, relative to the isolated SMBH case, the TDE and HVS rates are enhanced for, respectively, the smallest and largest mass ratio SMBH-SMBH binaries. This suggests that the observed event rates of TDEs and HVSs have the potential to serve as a diagnostic of the mass ratio of a central SMBH-SMBH binary. The presence of a secondary SMBH also allows for the creation of hypervelocity binaries. Observations of these systems could thus constrain the presence of a secondary SMBH in the Galactic Centre.

  11. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Kaltenegger, Lisa [MPIA, Koenigstuhl 17, D-69117 Heidelberg (Germany); Haghighipour, Nader, E-mail: kaltenegger@mpia.de [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

    2013-11-10

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886.

  12. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    International Nuclear Information System (INIS)

    Kaltenegger, Lisa; Haghighipour, Nader

    2013-01-01

    We have developed a comprehensive methodology for calculating the boundaries of the habitable zone (HZ) of planet-hosting S-type binary star systems. Our approach is general and takes into account the contribution of both stars to the location and extent of the binary HZ with different stellar spectral types. We have studied how the binary eccentricity and stellar energy distribution affect the extent of the HZ. Results indicate that in binaries where the combination of mass-ratio and orbital eccentricity allows planet formation around a star of the system to proceed successfully, the effect of a less luminous secondary on the location of the primary's HZ is generally negligible. However, when the secondary is more luminous, it can influence the extent of the HZ. We present the details of the derivations of our methodology and discuss its application to the binary HZ around the primary and secondary main-sequence stars of an FF, MM, and FM binary, as well as two known planet-hosting binaries α Cen AB and HD 196886

  13. Swift/XRT detection of an X-ray flare and jet emission from Cir X-1

    Science.gov (United States)

    Kong, A. K. H.; Yang, Y.-J.

    2010-06-01

    Following the detection of a brightening and several X-ray bursts of Cir X-1 (ATel #2608,#2643,#2650,#2651,#2653; Linares et al. arXiv:1006.1379), the source has returned to low flux level since June based on observations taken with RXTE/ASM and MAXI/GSC. We examined the Swift/XRT imaging mode data taken on 2010 June 6 and June 10. On June 6 (at orbital phase 0.8; defined by Stewart et al. 1993), the 0.3-10 keV XRT count rate of Cir X-1 is about 0.07 c/s while it brightened to 0.8 c/s on June 10 (at phase 0.03).

  14. BROWN DWARF BINARIES FROM DISINTEGRATING TRIPLE SYSTEMS

    International Nuclear Information System (INIS)

    Reipurth, Bo; Mikkola, Seppo

    2015-01-01

    Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi–Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

  15. BROWN DWARF BINARIES FROM DISINTEGRATING TRIPLE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Reipurth, Bo [Institute for Astronomy and NASA Astrobiology Institute University of Hawaii, 640 N. Aohoku Place, Hilo, HI 96720 (United States); Mikkola, Seppo, E-mail: reipurth@ifa.hawaii.edu, E-mail: Seppo.Mikkola@utu.fi [Tuorla Observatory, University of Turku, Väisäläntie 20, Piikkiö (Finland)

    2015-04-15

    Binaries in which both components are brown dwarfs (BDs) are being discovered at an increasing rate, and their properties may hold clues to their origin. We have carried out 200,000 N-body simulations of three identical stellar embryos with masses drawn from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions within the cloud core, while accreting using Bondi–Hoyle accretion. The coupling of dynamics and accretion often leads to one or two dominant bodies controlling the center of the cloud core, while banishing the other(s) to the lower-density outskirts, leading to stunted growth. Eventually each system transforms either to a bound hierarchical configuration or breaks apart into separate single and binary components. The orbital motion is followed for 100 Myr. In order to illustrate 200,000 end-states of such dynamical evolution with accretion, we introduce the “triple diagnostic diagram,” which plots two dimensionless numbers against each other, representing the binary mass ratio and the mass ratio of the third body to the total system mass. Numerous freefloating BD binaries are formed in these simulations, and statistical properties are derived. The separation distribution function is in good correspondence with observations, showing a steep rise at close separations, peaking around 13 AU and declining more gently, reaching zero at separations greater than 200 AU. Unresolved BD triple systems may appear as wider BD binaries. Mass ratios are strongly peaked toward unity, as observed, but this is partially due to the initial assumptions. Eccentricities gradually increase toward higher values, due to the lack of viscous interactions in the simulations, which would both shrink the orbits and decrease their eccentricities. Most newborn triple systems are unstable and while there are 9209 ejected BD binaries at 1 Myr, corresponding to about 4% of the 200,000 simulations, this number has grown to

  16. The theoretical character of the X1Σ+ and A1Σ+ states of ScN

    International Nuclear Information System (INIS)

    Feng-Juan, Bai; Chuan-Lu, Yang; Qi, Qian; Ling, Zhang

    2009-01-01

    This paper calculates the potential energy curves (PECs) of the ground state (X 1 Σ + ) and excited state (A 1 Σ + ) of ScN molecule by multireference configuration interaction method. The correct character of the PECs has been gripped while they had been improperly reported in the literature. Based on the PECs, the spectroscopic parameters and vibrational energy levels are determined, and compared with experimental data and other theoretical works available at the present. (atomic and molecular physics)

  17. X-RAY OUTFLOWS AND SUPER-EDDINGTON ACCRETION IN THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1

    International Nuclear Information System (INIS)

    Walton, D. J.; Harrison, F. A.; Miller, J. M.; Reis, R. C.; Fabian, A. C.; Roberts, T. P.; Middleton, M. J.

    2013-01-01

    Studies of X-ray continuum emission and flux variability have not conclusively revealed the nature of ultraluminous X-ray sources (ULXs) at the high-luminosity end of the distribution (those with L X ≥ 10 40 erg s –1 ). These are of particular interest because the luminosity requires either super-Eddington accretion onto a black hole of mass ∼10 M ☉ or more standard accretion onto an intermediate-mass black hole. Super-Eddington accretion models predict strong outflowing winds, making atomic absorption lines a key diagnostic of the nature of extreme ULXs. To search for such features, we have undertaken a long, 500 ks observing campaign on Holmberg IX X-1 with Suzaku. This is the most sensitive data set in the iron K bandpass for a bright, isolated ULX to date, yet we find no statistically significant atomic features in either emission or absorption; any undetected narrow features must have equivalent widths less than 15-20 eV at 99% confidence. These limits are far below the ∼>150 eV lines expected if observed trends between mass inflow and outflow rates extend into the super-Eddington regime and in fact rule out the line strengths observed from disk winds in a variety of sub-Eddington black holes. We therefore cannot be viewing the central regions of Holmberg IX X-1 through any substantial column of material, ruling out models of spherical super-Eddington accretion. If Holmberg IX X-1 is a super-Eddington source, any associated outflow must have an anisotropic geometry. Finally, the lack of iron emission suggests that the stellar companion cannot be launching a strong wind and that Holmberg IX X-1 must primarily accrete via Roche-lobe overflow

  18. Adsorption of RuSex (x =1–5) cluster on Se-doped graphene: First principle calculations

    International Nuclear Information System (INIS)

    Üzengi Aktürk, O.; Tomak, M.

    2015-01-01

    Highlights: • Electronic properties of adsorption of RuSe x (x =1–5) cluster on Se-doped graphene are investigated. • It is found that RuSe, RuSe 4 , RuSe 5 adsorbate make substrate metallic. • RuSe 2 makes it half metallic and RuSe 3 makes semiconductor. - Abstract: We have investigated the adsorption of RuSe x (x =1–5) cluster on Se-doped graphene. The change of the adsorption energy with the number of Se atoms and magnetization values are investigated. Electronic properties of adsorption of RuSe x (x =1–5) cluster on Se-doped graphene are investigated. The highest adsorption energy belongs to RuSe adsorbate. The biggest magnetization value belongs to RuSe 2 adsorbate. This adsorbate makes the substrate half metallic. This property is important in electronic device applications. It is observed that substitutional Se atom changes the electronic properties of graphene. This substitution makes graphene metallic. While RuSe, RuSe 4 , RuSe 5 adsorbate make substrate metallic, RuSe 3 makes it semiconducting. Generally, it is found that there is a charge transfer from the substrate to clusters within the Löwdin analysis. This is in line with the charge difference results

  19. Ultracompact X-ray binary stars

    NARCIS (Netherlands)

    Haaften, L.M. van

    2013-01-01

    Ultracompact X-ray binary stars usually consist of a neutron star and a white dwarf, two stars bound together by their strong gravity and orbiting each other very rapidly, completing one orbit in less than one hour. Neutron stars are extremely compact remnants of the collapsed cores of massive stars

  20. Jet precession in binary black holes

    Science.gov (United States)

    Abraham, Zulema

    2018-06-01

    Supermassive binary black holes are thought to lie at the centres of merging galaxies. The blazar OJ 287 is the poster child of such systems, showing strong and periodic variability across the electromagnetic spectrum. A new study questions the physical origin of this variability.

  1. Mesoscopic electrohydrodynamic simulations of binary colloidal suspensions

    NARCIS (Netherlands)

    Rivas, Nicolas; Frijters, Stefan; Pagonabarraga, Ignacio; Harting, Jens

    2018-01-01

    A model is presented for the solution of electrokinetic phenomena of colloidal suspensions in fluid mixtures. We solve the discrete Boltzmann equation with a Bhatnagar-Gross-Krook collision operator using the lattice Boltzmann method to simulate binary fluid flows. Solvent-solvent and solvent-solute

  2. Smoothed analysis of binary search trees

    NARCIS (Netherlands)

    Manthey, Bodo; Reischuk, Rüdiger

    2007-01-01

    Binary search trees are one of the most fundamental data structures. While the height of such a tree may be linear in the worst case, the average height with respect to the uniform distribution is only logarithmic. The exact value is one of the best studied problems in average-case complexity. We

  3. A coinductive calculus of binary trees

    NARCIS (Netherlands)

    A.M. Silva (Alexandra); J.J.M.M. Rutten (Jan)

    2007-01-01

    htmlabstractWe study the set T_A of infinite binary trees with nodes labelled in a semiring A from a coalgebraic perspective. We present coinductive definition and proof principles based on the fact that T_A carries a final coalgebra structure. By viewing trees as formal power series, we develop a

  4. Binary palmprint representation for feature template protection

    NARCIS (Netherlands)

    Mu, Meiru; Ruan, Qiuqi; Shao, X.; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.

    2012-01-01

    The major challenge of biometric template protection comes from the intraclass variations of biometric data. The helper data scheme aims to solve this problem by employing the Error Correction Codes (ECC). However, many reported biometric binary features from the same user reach bit error rate (BER)

  5. The average size of ordered binary subgraphs

    NARCIS (Netherlands)

    van Leeuwen, J.; Hartel, Pieter H.

    To analyse the demands made on the garbage collector in a graph reduction system, the change in size of an average graph is studied when an arbitrary edge is removed. In ordered binary trees the average number of deleted nodes as a result of cutting a single edge is equal to the average size of a

  6. Short-timescale variability in cataclysmic binaries

    International Nuclear Information System (INIS)

    Cordova, F.A.; Mason, K.O.

    1982-01-01

    Rapid variability, including flickering and pulsations, has been detected in cataclysmic binaries at optical and x-ray frequencies. In the case of the novalike variable TT Arietis, simultaneous observations reveal that the x-ray and optical flickering activity is strongly correlated, while short period pulsations are observed that occur at the same frequencies in both wavelength bands

  7. Non-binary or genderqueer genders.

    Science.gov (United States)

    Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John; Nieder, Timo O; T'Sjoen, Guy

    2016-01-01

    Some people have a gender which is neither male nor female and may identify as both male and female at one time, as different genders at different times, as no gender at all, or dispute the very idea of only two genders. The umbrella terms for such genders are 'genderqueer' or 'non-binary' genders. Such gender identities outside of the binary of female and male are increasingly being recognized in legal, medical and psychological systems and diagnostic classifications in line with the emerging presence and advocacy of these groups of people. Population-based studies show a small percentage--but a sizable proportion in terms of raw numbers--of people who identify as non-binary. While such genders have been extant historically and globally, they remain marginalized, and as such--while not being disorders or pathological in themselves--people with such genders remain at risk of victimization and of minority or marginalization stress as a result of discrimination. This paper therefore reviews the limited literature on this field and considers ways in which (mental) health professionals may assist the people with genderqueer and non-binary gender identities and/or expressions they may see in their practice. Treatment options and associated risks are discussed.

  8. Some thoughts on interacting binary systems

    International Nuclear Information System (INIS)

    Ulrich, R.K.

    1980-01-01

    The author presents some thoughts on the theory and observation of interacting binary systems. The complex physical processes possible in these systems make our present understanding inconclusive. New types of observation (X-ray, EUV, radio) present new challenges to the theoretician. The author discusses those problems which seem to hold the most promise for future progress. (Auth.)

  9. Mass loss from interacting close binary systems

    Science.gov (United States)

    Plavec, M. J.

    1981-01-01

    The three well-defined classes of evolved binary systems that show evidence of present and/or past mass loss are the cataclysmic variables, the Algols, and Wolf-Rayet stars. It is thought that the transformation of supergiant binary systems into the very short-period cataclysmic variables must have been a complex process. The new evidence that has recently been obtained from the far ultraviolet spectra that a certain subclass of the Algols (the Serpentids) are undergoing fairly rapid evolution is discussed. It is thought probable that the remarkable mass outflow observed in them is connected with a strong wind powered by accretion. The origin of the circumbinary clouds or flat disks that probably surround many strongly interacting binaries is not clear. Attention is also given to binary systems with hot white dwarf or subdwarf components, such as the symbiotic objects and the BQ stars; it is noted that in them both components may be prone to an enhanced stellar wind.

  10. Stretchable Binary Fresnel Lens for Focus Tuning

    NARCIS (Netherlands)

    Li, X.; Wei, L.; Poelma, R.H.; Vollebregt, S.; Wei, J.; Urbach, Paul; Sarro, P.M.; Zhang, G.Q.

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material

  11. Flip-flopping binary black holes.

    Science.gov (United States)

    Lousto, Carlos O; Healy, James

    2015-04-10

    We study binary spinning black holes to display the long term individual spin dynamics. We perform a full numerical simulation starting at an initial proper separation of d≈25M between equal mass holes and evolve them down to merger for nearly 48 orbits, 3 precession cycles, and half of a flip-flop cycle. The simulation lasts for t=20 000M and displays a total change in the orientation of the spin of one of the black holes from an initial alignment with the orbital angular momentum to a complete antialignment after half of a flip-flop cycle. We compare this evolution with an integration of the 3.5 post-Newtonian equations of motion and spin evolution to show that this process continuously flip flops the spin during the lifetime of the binary until merger. We also provide lower order analytic expressions for the maximum flip-flop angle and frequency. We discuss the effects this dynamics may have on spin growth in accreting binaries and on the observational consequences for galactic and supermassive binary black holes.

  12. Compiler-Agnostic Function Detection in Binaries

    NARCIS (Netherlands)

    Andriesse, D.A.; Slowinska, J.M.; Bos, H.J.

    2017-01-01

    We propose Nucleus, a novel function detection algorithm for binaries. In contrast to prior work, Nucleus is compiler-agnostic, and does not require any learning phase or signature information. Instead of scanning for signatures, Nucleus detects functions at the Control Flow Graph-level, making it

  13. Photometric survey of asynchronous binary asteroids

    Czech Academy of Sciences Publication Activity Database

    Pravec, Petr; Scheirich, Peter; Kušnirák, Peter; Kotková, Lenka; Mottola, S.; Hahn, G.; Brown, P.; Esquerdo, G.; Kaiser, K.; Krzeminski, Z.; Pray, D. P.; Warner, B. D.; Harris, A. W.; Nolan, M. C.; Howell, E. S.; Benner, L. A. M.; Margot, J. L.; Galád, Adrián; Holliday, W.; Hicks, M. D.; Krugly, Yu. N.; Tholen, D.; Whiteley, R.; Marchis, F.; DeGraff, D. R.; Grauer, A.; Larson, S. M.; Velichko, F. P.; Cooney, W.R.; Stephens, R.; Zhu, J.; Kirsch, K.; Dyvig, R.; Snyder, L.; Reddy, V.; Moore, S.; Gajdoš, Š.; Világi, J.; Masi, G.; Higgins, D.; Funkhouser, G. M.; Knight, B.; Slivan, S. M.; Behrend, R.; Grenon, M.; Burki, G.; Roy, R.; Demeautis, C.; Matter, D.; Waelchli, N.; Revaz, Y.; Klotz, A.; Rieugné, M.; Thieri, P.; Cotrez, V.; Brunetto, L.; Kober, G.

    2006-01-01

    Roč. 181, č. 1 (2006), s. 63-93 ISSN 0019-1035 R&D Projects: GA ČR GA205/05/0604; GA AV ČR IAA3003204 Institutional research plan: CEZ:AV0Z10030501 Keywords : asteroids * binary * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.151, year: 2006

  14. Planar quark diagrams and binary spin processes

    International Nuclear Information System (INIS)

    Grigoryan, A.A.; Ivanov, N.Ya.

    1986-01-01

    Contributions of planar diagrams to the binary scattering processes are analyzed. The analysis is based on the predictions of quark-gluon picture of strong interactions for the coupling of reggeons with quarks as well as on the SU(6)-classification of hadrons. The dependence of contributions of nonplanar corrections on spins and quark composition of interacting particles is discussed

  15. Binary translation using peephole translation rules

    Science.gov (United States)

    Bansal, Sorav; Aiken, Alex

    2010-05-04

    An efficient binary translator uses peephole translation rules to directly translate executable code from one instruction set to another. In a preferred embodiment, the translation rules are generated using superoptimization techniques that enable the translator to automatically learn translation rules for translating code from the source to target instruction set architecture.

  16. Predicting Social Trust with Binary Logistic Regression

    Science.gov (United States)

    Adwere-Boamah, Joseph; Hufstedler, Shirley

    2015-01-01

    This study used binary logistic regression to predict social trust with five demographic variables from a national sample of adult individuals who participated in The General Social Survey (GSS) in 2012. The five predictor variables were respondents' highest degree earned, race, sex, general happiness and the importance of personally assisting…

  17. Face Alignment via Regressing Local Binary Features.

    Science.gov (United States)

    Ren, Shaoqing; Cao, Xudong; Wei, Yichen; Sun, Jian

    2016-03-01

    This paper presents a highly efficient and accurate regression approach for face alignment. Our approach has two novel components: 1) a set of local binary features and 2) a locality principle for learning those features. The locality principle guides us to learn a set of highly discriminative local binary features for each facial landmark independently. The obtained local binary features are used to jointly learn a linear regression for the final output. This approach achieves the state-of-the-art results when tested on the most challenging benchmarks to date. Furthermore, because extracting and regressing local binary features are computationally very cheap, our system is much faster than previous methods. It achieves over 3000 frames per second (FPS) on a desktop or 300 FPS on a mobile phone for locating a few dozens of landmarks. We also study a key issue that is important but has received little attention in the previous research, which is the face detector used to initialize alignment. We investigate several face detectors and perform quantitative evaluation on how they affect alignment accuracy. We find that an alignment friendly detector can further greatly boost the accuracy of our alignment method, reducing the error up to 16% relatively. To facilitate practical usage of face detection/alignment methods, we also propose a convenient metric to measure how good a detector is for alignment initialization.

  18. Structure Map for Embedded Binary Alloy Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, C.W.; Shin, S.J.; Liao, C.Y.; Guzman, J.; Stone, P.R.; Watanabe, M.; Ager III, J.W.; Haller, E.E.; Chrzan, D.C.

    2008-09-20

    The equilibrium structure of embedded nanocrystals formed from strongly segregating binary-alloys is considered within a simple thermodynamic model. The model identifies two dimensionlessinterface energies that dictate the structure, and allows prediction of the stable structure for anychoice of these parameters. The resulting structure map includes three distinct nanocrystal mor-phologies: core/shell, lobe/lobe, and completely separated spheres.

  19. ANGULAR-MOMENTUM IN BINARY SPIRAL GALAXIES

    NARCIS (Netherlands)

    OOSTERLOO, T

    In order to investigate the relative orientations of spiral galaxies in pairs, the distribution of the angle between the spin-vectors for a new sample of 40 binary spiral galaxies is determined. From this distribution it is found, contrary to an earlier result obtained by Helou (1984), that there is

  20. Gravitational waves from binary black holes

    Indian Academy of Sciences (India)

    Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore ... In the 1916 paper exploring the physical implications of GR, Einstein .... Thus, for a neutron star binary in the Virgo cluster (D = 18 Mpc; 5.6×1020 km) the strain.

  1. The Binary Pulsar: Gravity Waves Exist.

    Science.gov (United States)

    Will, Clifford

    1987-01-01

    Reviews the history of pulsars generally and the 1974 discovery of the binary pulsar by Joe Taylor and Russell Hulse specifically. Details the data collection and analysis used by Taylor and Hulse. Uses this discussion as support for Albert Einstein's theory of gravitational waves. (CW)

  2. Receptive fields selection for binary feature description.

    Science.gov (United States)

    Fan, Bin; Kong, Qingqun; Trzcinski, Tomasz; Wang, Zhiheng; Pan, Chunhong; Fua, Pascal

    2014-06-01

    Feature description for local image patch is widely used in computer vision. While the conventional way to design local descriptor is based on expert experience and knowledge, learning-based methods for designing local descriptor become more and more popular because of their good performance and data-driven property. This paper proposes a novel data-driven method for designing binary feature descriptor, which we call receptive fields descriptor (RFD). Technically, RFD is constructed by thresholding responses of a set of receptive fields, which are selected from a large number of candidates according to their distinctiveness and correlations in a greedy way. Using two different kinds of receptive fields (namely rectangular pooling area and Gaussian pooling area) for selection, we obtain two binary descriptors RFDR and RFDG .accordingly. Image matching experiments on the well-known patch data set and Oxford data set demonstrate that RFD significantly outperforms the state-of-the-art binary descriptors, and is comparable with the best float-valued descriptors at a fraction of processing time. Finally, experiments on object recognition tasks confirm that both RFDR and RFDG successfully bridge the performance gap between binary descriptors and their floating-point competitors.

  3. Binary nucleation of water and sodium chloride

    Czech Academy of Sciences Publication Activity Database

    Němec, Tomáš; Maršík, František; Palmer, A.

    2006-01-01

    Roč. 124, č. 4 (2006), 0445091-0445096 ISSN 0021-9606 R&D Projects: GA ČR(CZ) GA101/05/2536 Institutional research plan: CEZ:AV0Z20760514 Keywords : binary nucleation * sodium chloride * water Subject RIV: BJ - Thermodynamics Impact factor: 3.166, year: 2006

  4. The Benchmark Eclipsing Binary V530 Ori

    DEFF Research Database (Denmark)

    Torres, Guillermo; Lacy, Claud H. Sandberg; Pavlovski, Kresimir

    2015-01-01

    We report accurate measurements of the physical properties (mass, radius, temperature) of components of the G+M eclipsing binary V530 On. The M-type secondary shows a larger radius and a cooler temperature than predicted by standard stellar evolution models, as has been found for many other low...

  5. Void formation in irradiated binary nickel alloys

    International Nuclear Information System (INIS)

    Shaikh, M.A.; Ahmed, M.; Akhter, J.I.

    1994-01-01

    In this work a computer program has been used to compute void radius, void density and swelling parameter for nickel and binary nickel-carbon alloys irradiated with nickel ions of 100 keV. The aim is to compare the computed results with experimental results already reported

  6. Evolution of binaries with compact objects in globular clusters

    OpenAIRE

    Ivanova, Natalia

    2017-01-01

    Dynamical interactions that take place between objects in dense stellar systems lead to frequent formation of exotic stellar objects, unusual binaries, and systems of higher multiplicity. They are most important for the formation of binaries with neutron stars and black holes, which are usually observationally revealed in mass-transferring binaries. Here we review the current understanding of compact object's retention, of the metallicity dependence on the formation of low-mass X-ray binaries...

  7. Influence of non-binary effects on intranuclear cascade method

    International Nuclear Information System (INIS)

    Gomes, E.H.C.

    1985-01-01

    The importance of non binary process effects in the intranuclear cascade method is analysed. It is shown that, in the higher density steps, the non binary collisions lead to baryon density distribution and rapidity differents from the one obtained using the usual intranuclear cascade method (limited to purely binary collisions). The validity of the applications of binary intranuclear cascade method to the simulation of the thermal equilibrium, nuclear transparency and particle production, is discussed. (M.C.K.) [pt

  8. Gravitational waves from spinning eccentric binaries

    Science.gov (United States)

    Csizmadia, Péter; Debreczeni, Gergely; Rácz, István; Vasúth, Mátyás

    2012-12-01

    This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations, while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems, it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity, thus confirming a similar result obtained by Brown and Zimmerman (2010 Phys. Rev. D 81 024007). In addition, by investigating the validity of the energy balance relation we show that, contrary to the general expectations, the PN approximation should not be applied once the PN parameter gets beyond the critical value ˜0.08 - 0.1. Finally, by studying the early phase of the gravitational waves emitted by strongly eccentric binary systems—which could be formed e.g. in various many-body interactions in the galactic halo—we have found that they possess very specific characteristics which may be used to identify these type of binary systems. This paper is dedicated to the memory of our colleague and friend Péter Csizmadia a young physicist, computer expert and one of the best Hungarian mountaineers who disappeared in China’s Sichuan near the Ren Zhong Feng peak of the Himalayas on 23 Oct. 2009. We started to develop CBwaves jointly with Péter a couple of months before he left for China.

  9. Probabilistic seismic history matching using binary images

    Science.gov (United States)

    Davolio, Alessandra; Schiozer, Denis Jose

    2018-02-01

    Currently, the goal of history-matching procedures is not only to provide a model matching any observed data but also to generate multiple matched models to properly handle uncertainties. One such approach is a probabilistic history-matching methodology based on the discrete Latin Hypercube sampling algorithm, proposed in previous works, which was particularly efficient for matching well data (production rates and pressure). 4D seismic (4DS) data have been increasingly included into history-matching procedures. A key issue in seismic history matching (SHM) is to transfer data into a common domain: impedance, amplitude or pressure, and saturation. In any case, seismic inversions and/or modeling are required, which can be time consuming. An alternative to avoid these procedures is using binary images in SHM as they allow the shape, rather than the physical values, of observed anomalies to be matched. This work presents the incorporation of binary images in SHM within the aforementioned probabilistic history matching. The application was performed with real data from a segment of the Norne benchmark case that presents strong 4D anomalies, including softening signals due to pressure build up. The binary images are used to match the pressurized zones observed in time-lapse data. Three history matchings were conducted using: only well data, well and 4DS data, and only 4DS. The methodology is very flexible and successfully utilized the addition of binary images for seismic objective functions. Results proved the good convergence of the method in few iterations for all three cases. The matched models of the first two cases provided the best results, with similar well matching quality. The second case provided models presenting pore pressure changes according to the expected dynamic behavior (pressurized zones) observed on 4DS data. The use of binary images in SHM is relatively new with few examples in the literature. This work enriches this discussion by presenting a new

  10. Full Ionisation In Binary-Binary Encounters With Small Positive Energies

    Science.gov (United States)

    Sweatman, W. L.

    2006-08-01

    Interactions between binary stars and single stars and binary stars and other binary stars play a key role in the dynamics of a dense stellar system. Energy can be transferred between the internal dynamics of a binary and the larger scale dynamics of the interacting objects. Binaries can be destroyed and created by the interaction. In a binary-binary encounter, full ionisation occurs when both of the binary stars are destroyed in the interaction to create four single stars. This is only possible when the total energy of the system is positive. For very small energies the probability of this occurring is very low and it tends towards zero as the total energy tends towards zero. Here the case is considered for which all the stars have equal masses. An asymptotic power law is predicted relating the probability of full ionisation with the total energy when this latter quantity is small. The exponent, which is approximately 2.31, is compared with the results from numerical scattering experiments. The theoretical approach taken is similar to one used previously in the three-body problem. It makes use of the fact that the most dramatic changes in scale and energies of a few-body system occur when its components pass near to a central configuration. The position, and number, of these configurations is not known for the general four-body problem, however, with equal masses there are known to be exactly five different cases. Separate consideration and comparison of the properties of orbits close to each of these five central configurations enables the prediction of the form of the cross-section for full ionisation for the case of small positive total energy. This is the relation between total energy and the probability of total ionisation described above.

  11. Planetary Formation and Dynamics in Binary Systems

    Science.gov (United States)

    Xie, J. W.

    2013-01-01

    As of today, over 500 exoplanets have been detected since the first exoplanet was discovered around a solar-like star in 1995. The planets in binaries could be common as stars are usually born in binary or multiple star systems. Although current observations show that the planet host rate in multiple star systems is around 17%, this fraction should be considered as a lower limit because of noticeable selection effects against binaries in planet searches. Most of the current known planet-bearing binary systems are S-types, meaning the companion star acts as a distant satellite, typically orbiting the inner star-planet system over 100 AU away. Nevertheless, there are four systems with a smaller separation of 20 AU, including the Gamma Cephei, GJ 86, HD 41004, and HD 196885. In addition to the planets in circumprimary (S-type) orbits discussed above, planets in circumbinary (P-type) orbits have been found in only two systems. In this thesis, we mainly study the planet formation in the S-type binary systems. In chapter 1, we first summarize current observational facts of exoplanets both in single-star and binary systems, then review the theoretical models of planet formation, with special attention to the application in binary systems. Perturbative effects from stellar companions render the planet formation process in binary systems even more complex than that in single-star systems. The perturbations from a binary companion can excite planetesimal orbits, and increase their mutual impact velocities to the values that might exceed their escape velocity or even the critical velocity for the onset of eroding collisions. The intermediate stage of the formation process---from planetesimals to planetary embryos---is thus the most problematic. In the following chapters, we investigate whether and how the planet formation goes through such a problematic stage. In chapter 2, we study the effects of gas dissipation on the planetesimals' mutual accretion. We find that in a

  12. Compact stars and the evolution of binary systems

    NARCIS (Netherlands)

    van den Heuvel, E.P.J.

    2011-01-01

    The Chandrasekhar limit is of key importance for the evolution of white dwarfs in binary systems and for the formation of neutron stars and black holes in binaries. Mass transfer can drive a white dwarf in a binary over the Chandrasekhar limit, which may lead to a Type Ia supernova (in case of a CO

  13. EVIDENCE FOR SIMULTANEOUS JETS AND DISK WINDS IN LUMINOUS LOW-MASS X-RAY BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Homan, Jeroen; Neilsen, Joseph; Allen, Jessamyn L.; Chakrabarty, Deepto; Remillard, Ronald A.; Schulz, Norbert [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue 37-582D, Cambridge, MA 02139 (United States); Fender, Rob [Astrophysics, Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Fridriksson, Joel K., E-mail: jeroen@space.mit.edu [Anton Pannekoek Institute, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands)

    2016-10-10

    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.

  14. A hard X-ray study of the ultraluminous X-ray source NGC 5204 X-1 with NuSTAR and XMM-Newton

    DEFF Research Database (Denmark)

    Mukherjee, E. S.; Walton, D. J.; Bachetti, M.

    2015-01-01

    We present the results from coordinated X-ray observations of the ultraluminous X-ray source NGC 5204 X-1 performed by the Nuclear Spectroscopic Telescope Array and XMM-Newton in early 2013. These observations provide the first detection of NGC 5204 X-1 above 10 keV, extending the broadband cover...

  15. Broadband X-ray spectra of the ultraluminous x-ray source Holmberg IX X-1 observed with NuSTAR, XMM-Newton, and Suzaku

    DEFF Research Database (Denmark)

    Walton, D. J.; Harrison, F. A.; Grefenstette, B. W.

    2014-01-01

    We present results from the coordinated broadband X-ray observations of the extreme ultraluminous X-ray source Holmberg IX X-1 performed by NuSTAR, XMM-Newton, and Suzaku in late 2012. These observations provide the first high-quality spectra of Holmberg IX X-1 above 10 keV to date, extending the...

  16. Atomic structure of a stable high-index Ge surface: G2(103)-(4x1)

    DEFF Research Database (Denmark)

    Seehofer, L.; Bunk, O.; Falkenberg, G.

    1997-01-01

    Based on scanning tunneling microscopy and surface X-ray diffraction, we propose a complex structural model for the Ge(103)-(4 x 1) reconstruction. Each unit cell contains two (103) double steps, which gives rise to the formation of stripes of Ge atoms oriented in the [] direction....... The stripes and the spaces between them are covered with threefold-coordinated Ge adatoms. Charge is transferred from the bulk-like edge atoms of the double steps to the adatoms. The formation of the reconstruction can be explained in terms of stress relief, charge transfer, and minimization of the dangling...

  17. Performance analysis and binary working fluid selection of combined flash-binary geothermal cycle

    International Nuclear Information System (INIS)

    Zeyghami, Mehdi

    2015-01-01

    Performance of the combined flash-binary geothermal power cycle for geofluid temperatures between 150 and 250 °C is studied. A thermodynamic model is developed, and the suitable binary working fluids for different geofluid temperatures are identified from a list of thirty working fluid candidates, consisting environmental friendly refrigerants and hydrocarbons. The overall system exergy destruction and Vapor Expansion Ratio across the binary cycle turbine are selected as key performance indicators. The results show that for low-temperature heat sources using refrigerants as binary working fluids result in higher overall cycle efficiency and for medium and high-temperature resources, hydrocarbons are more suitable. For combined flash-binary cycle, secondary working fluids; R-152a, Butane and Cis-butane show the best performances at geofluid temperatures 150, 200 and 250 °C respectively. The overall second law efficiency is calculated as high as 0.48, 0.55 and 0.58 for geofluid temperatures equal 150, 200 and 250 °C respectively. The flash separator pressure found to has important effects on cycle operation and performance. Separator pressure dictates the work production share of steam and binary parts of the system. And there is an optimal separator pressure at which overall exergy destruction of the cycle achieves its minimum value. - Highlights: • Performance of the combined flash-binary geothermal cycle is investigated. • Thirty different fluids are screened to find the most suitable ORC working fluid. • Optimum cycle operation conditions presented for geofluids between 150 °C and 250 °C. • Refrigerants are more suitable for the ORC at geothermal sources temperature ≤200 °C. • Hydrocarbons are more suitable for the ORC at geothermal sources temperature >200 °C

  18. COMMON PATTERNS IN THE EVOLUTION BETWEEN THE LUMINOUS NEUTRON STAR LOW-MASS X-RAY BINARY SUBCLASSES

    International Nuclear Information System (INIS)

    Fridriksson, Joel K.; Homan, Jeroen; Remillard, Ronald A.

    2015-01-01

    The X-ray transient XTE J1701–462 was the first source observed to evolve through all known subclasses of low-magnetic-field neutron star low-mass X-ray binaries (NS-LMXBs), as a result of large changes in its mass accretion rate. To investigate to what extent similar evolution is seen in other NS-LMXBs we have performed a detailed study of the color–color and hardness–intensity diagrams (CDs and HIDs) of Cyg X-2, Cir X-1, and GX 13+1—three luminous X-ray binaries, containing weakly magnetized neutron stars, known to exhibit strong secular changes in their CD/HID tracks. Using the full set of Rossi X-ray Timing Explorer Proportional Counter Array data collected for the sources over the 16 year duration of the mission, we show that Cyg X-2 and Cir X-1 display CD/HID evolution with close similarities to XTE J1701–462. Although GX 13+1 shows behavior that is in some ways unique, it also exhibits similarities to XTE J1701–462, and we conclude that its overall CD/HID properties strongly indicate that it should be classified as a Z source, rather than as an atoll source. We conjecture that the secular evolution of Cyg X-2, Cir X-1, and GX 13+1—illustrated by sequences of CD/HID tracks we construct—arises from changes in the mass accretion rate. Our results strengthen previous suggestions that within single sources Cyg-like Z source behavior takes place at higher luminosities and mass accretion rates than Sco-like Z behavior, and lend support to the notion that the mass accretion rate is the primary physical parameter distinguishing the various NS-LMXB subclasses

  19. COMMON PATTERNS IN THE EVOLUTION BETWEEN THE LUMINOUS NEUTRON STAR LOW-MASS X-RAY BINARY SUBCLASSES

    Energy Technology Data Exchange (ETDEWEB)

    Fridriksson, Joel K. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Homan, Jeroen; Remillard, Ronald A., E-mail: J.K.Fridriksson@uva.nl [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2015-08-10

    The X-ray transient XTE J1701–462 was the first source observed to evolve through all known subclasses of low-magnetic-field neutron star low-mass X-ray binaries (NS-LMXBs), as a result of large changes in its mass accretion rate. To investigate to what extent similar evolution is seen in other NS-LMXBs we have performed a detailed study of the color–color and hardness–intensity diagrams (CDs and HIDs) of Cyg X-2, Cir X-1, and GX 13+1—three luminous X-ray binaries, containing weakly magnetized neutron stars, known to exhibit strong secular changes in their CD/HID tracks. Using the full set of Rossi X-ray Timing Explorer Proportional Counter Array data collected for the sources over the 16 year duration of the mission, we show that Cyg X-2 and Cir X-1 display CD/HID evolution with close similarities to XTE J1701–462. Although GX 13+1 shows behavior that is in some ways unique, it also exhibits similarities to XTE J1701–462, and we conclude that its overall CD/HID properties strongly indicate that it should be classified as a Z source, rather than as an atoll source. We conjecture that the secular evolution of Cyg X-2, Cir X-1, and GX 13+1—illustrated by sequences of CD/HID tracks we construct—arises from changes in the mass accretion rate. Our results strengthen previous suggestions that within single sources Cyg-like Z source behavior takes place at higher luminosities and mass accretion rates than Sco-like Z behavior, and lend support to the notion that the mass accretion rate is the primary physical parameter distinguishing the various NS-LMXB subclasses.

  20. WHITE-LIGHT FLARES ON CLOSE BINARIES OBSERVED WITH KEPLER

    International Nuclear Information System (INIS)

    Gao, Qing; Xin, Yu; Liu, Ji-Feng; Zhang, Xiao-Bin; Gao, Shuang

    2016-01-01

    Based on Kepler data, we present the results of a search for white light flares on 1049 close binaries. We identify 234 flare binaries, of which 6818 flares are detected. We compare the flare-binary fraction in different binary morphologies (“detachedness”). The result shows that the fractions in over-contact and ellipsoidal binaries are approximately 10%–20% lower than those in detached and semi-detached systems. We calculate the binary flare activity level (AL) of all the flare binaries, and discuss its variations along the orbital period ( P orb ) and rotation period ( P rot , calculated for only detached binaries). We find that the AL increases with decreasing P orb or P rot , up to the critical values at P orb ∼ 3 days or P rot ∼ 1.5 days, and thereafter the AL starts decreasing no matter how fast the stars rotate. We examine the flaring rate as a function of orbital phase in two eclipsing binaries on which a large number of flares are detected. It appears that there is no correlation between flaring rate and orbital phase in these two binaries. In contrast, when we examine the function with 203 flares on 20 non-eclipse ellipsoidal binaries, bimodal distribution of amplitude-weighted flare numbers shows up at orbital phases 0.25 and 0.75. Such variation could be larger than what is expected from the cross section modification.

  1. Tidal effects in twin-degenerate binaries

    International Nuclear Information System (INIS)

    Campbell, C.G.

    1984-01-01

    The tidal velocity field is calculated for an initially non-rotating low mass white dwarf secondary in a twin-degenerate binary. These motions are used to find the tidal torque on the secondary, to first order in the orbital frequency, and an expression is derived for the synchronization time. For a lobe-filling secondary the synchronization time has a weak dependence on the mass and luminosity of the star, and for the binary G61-29 is found to be of the same order as the estimated lifetime of the system. It is emphasized, however, that tidal excitation of non-radial oscillatory modes in the secondary may significantly shorten the synchronization time. (author)

  2. Image Steganalysis with Binary Similarity Measures

    Directory of Open Access Journals (Sweden)

    Kharrazi Mehdi

    2005-01-01

    Full Text Available We present a novel technique for steganalysis of images that have been subjected to embedding by steganographic algorithms. The seventh and eighth bit planes in an image are used for the computation of several binary similarity measures. The basic idea is that the correlation between the bit planes as well as the binary texture characteristics within the bit planes will differ between a stego image and a cover image. These telltale marks are used to construct a classifier that can distinguish between stego and cover images. We also provide experimental results using some of the latest steganographic algorithms. The proposed scheme is found to have complementary performance vis-à-vis Farid's scheme in that they outperform each other in alternate embedding techniques.

  3. EXOSAT and IUE observations of contact binaries

    International Nuclear Information System (INIS)

    Vilhu, O.; Heise, J.; Laboratorium voor Ruimteonderzoek, Utrecht, Netherlands)

    1986-01-01

    EXOSAT observations are reported of the contact binaries W UMa, VW Cep, 44t Boo, XY Leo, and V566 Oph and the detached short-period RS CVn stars ER Vul and HD 209943. Complete X-ray light curves were obtained for W UMa, VW Cep and 44t Boo. Nearly simultaneous IUE observations of VW Cep provide important comparisons of the Mg II emission, the UV continuum, and the FES light curve, pointing to extra hot gas at phase 0.75. The observations indicate that contact binaries have highly structured (in temperature and geometry) and highly variable coronae, not preferentially connected with either of the component stars. The observed dips can be interpreted as due to cool absorbing clouds above localized X-ray emitting regions. For VW Cep, 44t Boo, and XY Leo there is evidence that the neck regions are sites for X-ray-emitting hot gas. 66 references

  4. On the dynamics of binary galaxies

    International Nuclear Information System (INIS)

    Verner, D.A.; Chernin, A.D.

    1987-01-01

    The dynamics of close noncontact binary galaxies is investigated. It is demonsrated that the tidal interaction is ineffective for circularization of galaxy orbits. Nonsphericity of galaxies develops a torque in a binary system. For a pair of elliptical galaxies this torque leads to swinging of the galaxies with respect to the orbital plane (which can be observed as a rotation about the minor axis) and to the excitation of internal degrees of freedom. Besides, this pendulum effect may be effective for elliptical galaxies in clusters due to the presence of the torque produced by a cluster as a whole. In the case of spiral galaxies the torque leads to the precession of their rotational axes. However this effect seems to be too weak to be observable

  5. Memory Vulnerability Diagnosis for Binary Program

    Directory of Open Access Journals (Sweden)

    Tang Feng-Yi

    2016-01-01

    Full Text Available Vulnerability diagnosis is important for program security analysis. It is a further step to understand the vulnerability after it is detected, as well as a preparatory step for vulnerability repair or exploitation. This paper mainly analyses the inner theories of major memory vulnerabilities and the threats of them. And then suggests some methods to diagnose several types of memory vulnerabilities for the binary programs, which is a difficult task due to the lack of source code. The diagnosis methods target at buffer overflow, use after free (UAF and format string vulnerabilities. We carried out some tests on the Linux platform to validate the effectiveness of the diagnosis methods. It is proved that the methods can judge the type of the vulnerability given a binary program.

  6. THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

    International Nuclear Information System (INIS)

    Brown, Warren R.; Kenyon, Scott J.; Kilic, Mukremin; Gianninas, A.; Allende Prieto, Carlos

    2013-01-01

    We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P ≤ 1 day) binaries. Our sample includes four objects with remarkable log g ≅ 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times 0.9 M ☉ companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

  7. Detectability of Gravitational Waves from High-Redshift Binaries.

    Science.gov (United States)

    Rosado, Pablo A; Lasky, Paul D; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto

    2016-03-11

    Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳10^{10}M_{⊙} can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.

  8. THE ELM SURVEY. V. MERGING MASSIVE WHITE DWARF BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Warren R.; Kenyon, Scott J. [Smithsonian Astrophysical Observatory, 60 Garden St, Cambridge, MA 02138 (United States); Kilic, Mukremin; Gianninas, A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK, 73019 (United States); Allende Prieto, Carlos, E-mail: wbrown@cfa.harvard.edu, E-mail: skenyon@cfa.harvard.edu, E-mail: kilic@ou.edu, E-mail: alexg@nhn.ou.edu, E-mail: callende@iac.es [Instituto de Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain)

    2013-05-20

    We present the discovery of 17 low-mass white dwarfs (WDs) in short-period (P {<=} 1 day) binaries. Our sample includes four objects with remarkable log g {approx_equal} 5 surface gravities and orbital solutions that require them to be double degenerate binaries. All of the lowest surface gravity WDs have metal lines in their spectra implying long gravitational settling times or ongoing accretion. Notably, six of the WDs in our sample have binary merger times <10 Gyr. Four have {approx}>0.9 M{sub Sun} companions. If the companions are massive WDs, these four binaries will evolve into stable mass transfer AM CVn systems and possibly explode as underluminous supernovae. If the companions are neutron stars, then these may be millisecond pulsar binaries. These discoveries increase the number of detached, double degenerate binaries in the ELM Survey to 54; 31 of these binaries will merge within a Hubble time.

  9. Stochastic simulation of nucleation in binary alloys

    Science.gov (United States)

    L’vov, P. E.; Svetukhin, V. V.

    2018-06-01

    In this study, we simulate nucleation in binary alloys with respect to thermal fluctuations of the alloy composition. The simulation is based on the Cahn–Hilliard–Cook equation. We have considered the influence of some fluctuation parameters (wave vector cutoff and noise amplitude) on the kinetics of nucleation and growth of minority phase precipitates. The obtained results are validated by the example of iron–chromium alloys.

  10. Evaporative lithographic patterning of binary colloidal films.

    Science.gov (United States)

    Harris, Daniel J; Conrad, Jacinta C; Lewis, Jennifer A

    2009-12-28

    Evaporative lithography offers a promising new route for patterning a broad array of soft materials. In this approach, a mask is placed above a drying film to create regions of free and hindered evaporation, which drive fluid convection and entrained particles to regions of highest evaporative flux. We show that binary colloidal films exhibit remarkable pattern formation when subjected to a periodic evaporative landscape during drying.

  11. Digitizing Villanova University's Eclipsing Binary Card Catalogue

    Science.gov (United States)

    Guzman, Giannina; Dalton, Briana; Conroy, Kyle; Prsa, Andrej

    2018-01-01

    Villanova University’s Department of Astrophysics and Planetary Science has years of hand-written archival data on Eclipsing Binaries at its disposal. This card catalog began at Princeton in the 1930’s with notable contributions from scientists such as Henry Norris Russel. During World War II, the archive was moved to the University of Pennsylvania, which was one of the world centers for Eclipsing Binary research, consequently, the contributions to the catalog during this time were immense. It was then moved to University of Florida at Gainesville before being accepted by Villanova in the 1990’s. The catalog has been kept in storage since then. The objective of this project is to digitize this archive and create a fully functional online catalog that contains the information available on the cards, along with the scan of the actual cards. Our group has built a database using a python-powered infrastructure to contain the collected data. The team also built a prototype web-based searchable interface as a front-end to the catalog. Following the data-entry process, information like the Right Ascension and Declination will be run against SIMBAD and any differences between values will be noted as part of the catalog. Information published online from the card catalog and even discrepancies in information for a star, could be a catalyst for new studies on these Eclipsing Binaries. Once completed, the database-driven interface will be made available to astronomers worldwide. The group will also acquire, from the database, a list of referenced articles that have yet to be found online in order to further pursue their digitization. This list will be comprised of references in the cards that were neither found on ADS nor online during the data-entry process. Pursuing the integration of these references to online queries such as ADS will be an ongoing process that will contribute and further facilitate studies on Eclipsing Binaries.

  12. A Bayesian model for binary Markov chains

    Directory of Open Access Journals (Sweden)

    Belkheir Essebbar

    2004-02-01

    Full Text Available This note is concerned with Bayesian estimation of the transition probabilities of a binary Markov chain observed from heterogeneous individuals. The model is founded on the Jeffreys' prior which allows for transition probabilities to be correlated. The Bayesian estimator is approximated by means of Monte Carlo Markov chain (MCMC techniques. The performance of the Bayesian estimates is illustrated by analyzing a small simulated data set.

  13. Unstable mass outflow from a binary system

    Energy Technology Data Exchange (ETDEWEB)

    Nariai, K [Tokyo Univ., Mitaka (Japan). Tokyo Astronomical Observatory; Sugimoto, D

    1976-12-01

    A contact binary system which fills the outer Lagrangian lobe is unstable against the mass loss from the second Lagrangian point. The effect of the mass loss on the remaining system is studied for several typical cases. It is shown that the separation between the components at the periastron decreases with a high rate in most cases; therefore, the system continues to lose mass once gas begins to flow out from the second Lagrangian point.

  14. Minimum degree and density of binary sequences

    DEFF Research Database (Denmark)

    Brandt, Stephan; Müttel, J.; Rautenbach, D.

    2010-01-01

    For d,k∈N with k ≤ 2d, let g(d,k) denote the infimum density of binary sequences (x)∈{0,1} which satisfy the minimum degree condition σ(x+) ≥ k for all i∈Z with xi=1. We reduce the problem of computing g(d,k) to a combinatorial problem related to the generalized k-girth of a graph G which...

  15. Composition profile determination in isomorphous binary alloys

    International Nuclear Information System (INIS)

    An, C.Y.; Bandeira, I.N.

    1983-07-01

    The inhomogeneity along the growth axis of the pseudo-binary alloys is due to the segregation of the solute which will be mixed in the melt due to convective and diffusive flows. A process for determination of the exact composition profile by measurements of the crystal density, for alloys of the type A sub(1-x) B sub(x), is shown. (Author) [pt

  16. Relativistic apsidal motion in eccentric eclipsing binaries

    Czech Academy of Sciences Publication Activity Database

    Wolf, M.; Claret, L.; Kotková, Lenka; Kučáková, Hana; Kocián, R.; Brát, L.; Svoboda, P.; Šmelcer, L.

    2010-01-01

    Roč. 509, January (2010), A18/1-A18/14 ISSN 0004-6361 Grant - others:GA ČR(CZ) GA205/04/2063; GA ČR(CZ) GA205/06/0217 Institutional research plan: CEZ:AV0Z10030501 Keywords : binaries eclipsing Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.410, year: 2010

  17. Formation and Evolution of Contact Binaries

    Directory of Open Access Journals (Sweden)

    Peter P. Eggleton

    2012-06-01

    Full Text Available describe a series of processes, including hierarchical fragmentation, gravitational scattering, Kozai cycles within triple systems, tidal friction and magnetic braking, that I believe are responsible for producing the modest but significant fraction of stars that are observed as contact binaries. I also discuss further processes, namely heat transport, mass transport, nuclear evolution, thermal relaxation oscillations, and further magnetic braking with tidal friction, that influence the evolution during contact. The endpoint, for contact, is that the two components merge into a single star, as recently was observed in the remarkable system V1309 Sco. The single star probably throws off some mass and rotates rapidly at first, and then slows by magnetic braking to become a rather inconspicuous but normal dwarf or subgiant. If however the contact binary was part of a triple system originally–as I suggested above was rather likely–then the result could be a widish binary with apparently non-coeval components. There are several such known.

  18. ORBITAL EVOLUTION OF COMPACT WHITE DWARF BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, David L. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211 (United States); Bildsten, Lars [Kavli Institute for Theoretical Physics and Department of Physics, Kohn Hall, University of California, Santa Barbara, CA 93106 (United States); Steinfadt, Justin D. R., E-mail: kaplan@uwm.edu, E-mail: bildsten@kitp.ucsb.edu, E-mail: jdrsteinfadt@gmail.com [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

    2012-10-10

    The newfound prevalence of extremely low mass (ELM, M{sub He} < 0.2 M{sub Sun }) helium white dwarfs (WDs) in tight binaries with more massive WDs has raised our interest in understanding the nature of their mass transfer. Possessing small (M{sub env} {approx} 10{sup -3} M{sub Sun }) but thick hydrogen envelopes, these objects have larger radii than cold WDs and so initiate mass transfer of H-rich material at orbital periods of 6-10 minutes. Building on the original work of D'Antona et al., we confirm the 10{sup 6} yr period of continued inspiral with mass transfer of H-rich matter and highlight the fact that the inspiraling direct-impact double WD binary HM Cancri likely has an ELM WD donor. The ELM WDs have less of a radius expansion under mass loss, thus enabling a larger range of donor masses that can stably transfer matter and become a He mass transferring AM CVn binary. Even once in the long-lived AM CVn mass transferring stage, these He WDs have larger radii due to their higher entropy from the prolonged H-burning stage.

  19. Constraining the Statistics of Population III Binaries

    Science.gov (United States)

    Stacy, Athena; Bromm, Volker

    2012-01-01

    We perform a cosmological simulation in order to model the growth and evolution of Population III (Pop III) stellar systems in a range of host minihalo environments. A Pop III multiple system forms in each of the ten minihaloes, and the overall mass function is top-heavy compared to the currently observed initial mass function in the Milky Way. Using a sink particle to represent each growing protostar, we examine the binary characteristics of the multiple systems, resolving orbits on scales as small as 20 AU. We find a binary fraction of approx. 36, with semi-major axes as large as 3000 AU. The distribution of orbital periods is slightly peaked at approx. < 900 yr, while the distribution of mass ratios is relatively flat. Of all sink particles formed within the ten minihaloes, approx. 50 are lost to mergers with larger sinks, and 50 of the remaining sinks are ejected from their star-forming disks. The large binary fraction may have important implications for Pop III evolution and nucleosynthesis, as well as the final fate of the first stars.

  20. Study of zirconium-addition binary systems

    International Nuclear Information System (INIS)

    Wozniakova, B.; Kuchar, L.

    1975-01-01

    The curves are given of the solid and the liquid of binary zirconium-addition systems. Most additions reduce the melting temperature of zirconium. The only known additions to increase the melting temperature are nitrogen, oxygen and hafnium. Also given are the transformation curves of the systems and the elements are given which reduce or raise the temperature of α-β transformation. From the Mendeleev table into which are plotted the curves of the solid and the liquid of binary systems it is possible to predict the properties of unknown binary systems. For the calculations of the curves of the solid and the liquid, 1860 degC was taken as the temperature of zirconium melting. For the calculations of transformation curves, 865 degC was taken as the temperature of α-β transformation. The equations are given of the curves of the solid and the liquid and of the transformation curves of some Zr-addition systems. Also given are the calculated equilibrium distribution coefficients and the equilibrium distribution coefficients of the transformation of additions in Zr and their limit values for temperatures approximating the melting point or the temperature of the transformation of pure Zr, and the values pertaining to eutectic and peritectic or eutectoid and peritectoid temperatures. (J.B.)

  1. On the binary expansions of algebraic numbers

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, David H.; Borwein, Jonathan M.; Crandall, Richard E.; Pomerance, Carl

    2003-07-01

    Employing concepts from additive number theory, together with results on binary evaluations and partial series, we establish bounds on the density of 1's in the binary expansions of real algebraic numbers. A central result is that if a real y has algebraic degree D > 1, then the number {number_sign}(|y|, N) of 1-bits in the expansion of |y| through bit position N satisfies {number_sign}(|y|, N) > CN{sup 1/D} for a positive number C (depending on y) and sufficiently large N. This in itself establishes the transcendency of a class of reals {summation}{sub n{ge}0} 1/2{sup f(n)} where the integer-valued function f grows sufficiently fast; say, faster than any fixed power of n. By these methods we re-establish the transcendency of the Kempner--Mahler number {summation}{sub n{ge}0}1/2{sup 2{sup n}}, yet we can also handle numbers with a substantially denser occurrence of 1's. Though the number z = {summation}{sub n{ge}0}1/2{sup n{sup 2}} has too high a 1's density for application of our central result, we are able to invoke some rather intricate number-theoretical analysis and extended computations to reveal aspects of the binary structure of z{sup 2}.

  2. Circumstellar disks around binary stars in Taurus

    International Nuclear Information System (INIS)

    Akeson, R. L.; Jensen, E. L. N.

    2014-01-01

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10 –4 M ☉ . We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F mm ∝M ∗ 1.5--2.0 to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  3. Circumstellar disks around binary stars in Taurus

    Energy Technology Data Exchange (ETDEWEB)

    Akeson, R. L. [NASA Exoplanet Science Institute, IPAC/Caltech, Pasadena, CA 91125 (United States); Jensen, E. L. N. [Swarthmore College, Department of Physics and Astronomy, Swarthmore, PA 19081 (United States)

    2014-03-20

    We have conducted a survey of 17 wide (>100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems as an aid to understanding the role of multiplicity in star and planet formation. The ALMA observations had sufficient resolution to localize emission within the binary system. Disk emission was detected around all primaries and 10 secondaries, with disk masses as low as 10{sup –4} M {sub ☉}. We compare the properties of our sample to the population of known disks in Taurus and find that the disks from this binary sample match the scaling between stellar mass and millimeter flux of F{sub mm}∝M{sub ∗}{sup 1.5--2.0} to within the scatter found in previous studies. We also compare the properties of the primaries to those of the secondaries and find that the secondary/primary stellar and disk mass ratios are not correlated; in three systems, the circumsecondary disk is more massive than the circumprimary disk, counter to some theoretical predictions.

  4. Observations of binary stars by speckle interferometry

    International Nuclear Information System (INIS)

    Morgan, B.L.; Beckmann, G.K.; Scaddan, R.J.

    1980-01-01

    This is the second paper in a series describing observations of binary stars using the technique of speckle interferometry. Observations were made using the 2.5-m Isaac Newton Telescope and the 1-m telescope of the Royal Greenwich Observatory and the 1.9-m telescope of the South African Astronomical Observatory. The classical Rayleigh diffraction limits are 0.050 arcsec for the 2.5-m telescope, 0.065 arcsec for the 1.9-m telescope and 0.125 arcsec for the 1-m telescope, at a wavelength of 500 nm. The results of 29 measurements of 26 objects are presented. The objects include long period spectroscopic binaries from the 6th Catalogue of Batten, close visual binary systems from the 3rd Catalogue of Finsen and Worley and variable stars. Nine of the objects have not been previously resolved by speckle interferometry. New members are detected in the systems β Cep, p Vel and iota UMa. (author)

  5. Orbital Decay in Binaries with Evolved Stars

    Science.gov (United States)

    Sun, Meng; Arras, Phil; Weinberg, Nevin N.; Troup, Nicholas; Majewski, Steven R.

    2018-01-01

    Two mechanisms are often invoked to explain tidal friction in binary systems. The ``dynamical tide” is the resonant excitation of internal gravity waves by the tide, and their subsequent damping by nonlinear fluid processes or thermal diffusion. The ``equilibrium tide” refers to non-resonant excitation of fluid motion in the star’s convection zone, with damping by interaction with the turbulent eddies. There have been numerous studies of these processes in main sequence stars, but less so on the subgiant and red giant branches. Motivated by the newly discovered close binary systems in the Apache Point Observatory Galactic Evolution Experiment (APOGEE-1), we have performed calculations of both the dynamical and equilibrium tide processes for stars over a range of mass as the star’s cease core hydrogen burning and evolve to shell burning. Even for stars which had a radiative core on the main sequence, the dynamical tide may have very large amplitude in the newly radiative core in post-main sequence, giving rise to wave breaking. The resulting large dynamical tide dissipation rate is compared to the equilibrium tide, and the range of secondary masses and orbital periods over which rapid orbital decay may occur will be discussed, as well as applications to close APOGEE binaries.

  6. Simulations of nearly extremal binary black holes

    Science.gov (United States)

    Giesler, Matthew; Scheel, Mark; Hemberger, Daniel; Lovelace, Geoffrey; Kuper, Kevin; Boyle, Michael; Szilagyi, Bela; Kidder, Lawrence; SXS Collaboration

    2015-04-01

    Astrophysical black holes could have nearly extremal spins; therefore, nearly extremal black holes could be among the binaries that current and future gravitational-wave observatories will detect. Predicting the gravitational waves emitted by merging black holes requires numerical-relativity simulations, but these simulations are especially challenging when one or both holes have mass m and spin S exceeding the Bowen-York limit of S /m2 = 0 . 93 . Using improved methods we simulate an unequal-mass, precessing binary black hole coalescence, where the larger black hole has S /m2 = 0 . 99 . We also use these methods to simulate a nearly extremal non-precessing binary black hole coalescence, where both black holes have S /m2 = 0 . 994 , nearly reaching the Novikov-Thorne upper bound for holes spun up by thin accretion disks. We demonstrate numerical convergence and estimate the numerical errors of the waveforms; we compare numerical waveforms from our simulations with post-Newtonian and effective-one-body waveforms; and we compare the evolution of the black-hole masses and spins with analytic predictions.

  7. Accreting Binary Populations in the Earlier Universe

    Science.gov (United States)

    Hornschemeier, Ann

    2010-01-01

    It is now understood that X-ray binaries dominate the hard X-ray emission from normal star-forming galaxies. Thanks to the deepest (2-4 Ms) Chandra surveys, such galaxies are now being studied in X-rays out to z approximates 4. Interesting X-ray stacking results (based on 30+ galaxies per redshift bin) suggest that the mean rest-frame 2-10 keV luminosity from z=3-4 Lyman break galaxies (LBGs), is comparable to the most powerful starburst galaxies in the local Universe. This result possibly indicates a similar production mechanism for accreting binaries over large cosmological timescales. To understand and constrain better the production of X-ray binaries in high-redshift LBGs, we have utilized XMM-Newton observations of a small sample of z approximates 0.1 GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs); local analogs to high-redshift LBGs. Our observations enable us to study the X-ray emission from LBG-like galaxies on an individual basis, thus allowing us to constrain object-to-object variances in this population. We supplement these results with X-ray stacking constraints using the new 3.2 Ms Chandra Deep Field-South (completed spring 2010) and LBG candidates selected from HST, Swift UVOT, and ground-based data. These measurements provide new X-ray constraints that sample well the entire z=0-4 baseline

  8. Evolution of massive close binary stars

    International Nuclear Information System (INIS)

    Masevich, A.G.; Tutukov, A.V.

    1982-01-01

    Some problems of the evolution of massive close binary stars are discussed. Most of them are nonevolutionized stars with close masses of components. After filling the Roche cavity and exchange of matter between the components the Wolf-Rayet star is formed. As a result of the supernovae explosion a neutron star or a black hole is formed in the system. The system does not disintegrate but obtains high space velocity owing to the loss of the supernovae envelope. The satellite of the neutron star or black hole - the star of the O or B spectral class loses about 10 -6 of the solar mass for a year. Around the neighbouring component a disc of this matter is formed the incidence of which on a compact star leads to X radiation appearance. The neutron star cannot absorb the whole matter of the widening component and the binary system submerges into the common envelope. As a result of the evolution of massive close binary systems single neutron stars can appear which after the lapse of some time become radiopulsars. Radiopulsars with such high space velocities have been found in our Galaxy [ru

  9. Spectral Study of A 1Π–X 1Σ+ Transitions of CO Relevant to Interstellar Clouds

    Science.gov (United States)

    Cheng, Junxia; Zhang, Hong; Cheng, Xinlu

    2018-05-01

    Highly correlated ab initio calculations were performed for an accurate determination of the A 1Π–X 1Σ+ system of the CO molecule. A highly accurate multi-reference configuration interaction approach was used to investigate the potential energy curves (PECs) and the transition dipole moment curve (TDMC). The resultant PECs and TDMC found by using the aug-cc-pV5Z (aV5Z) basis set and 5330 active spaces are in good agreement with the experimental data. Moreover, the Einstein A coefficients, lifetimes, ro-vibrational intensities, absorption oscillator strengths, and integrated cross sections are calculated so that the vibrational bands include v″ = 0–39 \\to v‧ = 0–23. For applications in the atmosphere and interstellar clouds, we studied the transition lineshapes to Gaussian and Lorentzian profiles at different temperatures and pressures. The intensities were calculated at high temperature that was used to satisfy some astrophysical applications, such as in planetary atmospheres. The results are potentially useful for important SAO/NASA Astrophysics Data System and databases such as HITRAN, HITEMP, and the National Institute of Standards and Technology. Because the results from many laboratory techniques and our calculations now agree, analyses of interstellar CO based on absorption from A 1Π–X 1Σ+ are no longer hindered by present spectral parameters.

  10. Hydroxyl group induced adsorption of four-nitro benzoic acid on Si(100) 2x1 surface

    International Nuclear Information System (INIS)

    Ihm, K.; Kang, T.-H.; Hwang, C.C.; Kim, K.-J.; Hwang, H.-N.; Kim, H.-D.; Han, J.H.; Moon, S.; Kim, B.; POSTECH

    2004-01-01

    Full text: A number of studies have been conducted on self-assembled monolayers (SAMs) in order to study the adhesion of polymer films on various substrates. Recently, the studies on SAMs on the semiconductor substrate are more motivated because of their possible application to nanoscale devices. For the electronic and chemical properties suitable for various applications, the aromatic ring has been used as a building block of various molecules forming SAMs. Here, we used four-nitro benzoic acid (4-NBA) as a model planar aromatic compound, in which the phenyl ring, the carboxylic functional group, and NO2 are on the same plane. The adsorption mechanism of 4-NBA on the in-situ prepared OH/Si(100) 2x1 surface was investigated using x-ray photoelectron spectroscopy and near-edge x-ray absorption e structure. The results revealed that the 4-NBA molecule reacts with the hydroxyl group on the Si(100) 2x1 surface through deprotonation of the carboxyl group. The saturation coverage of 4-NBA estimated by the O 1s ratio is 1/2 ML. Additionally, we could observe the desorption of the oxygen atom from the NO2 moiety of the 4-NBA upon irradiating the surface by photons of 500 eV

  11. On the Composition and Neutrix Composition of the Delta Function and the Function cosh^{-1}(|x|^{1/r}+1

    Directory of Open Access Journals (Sweden)

    Brian Fisher

    2017-03-01

    Full Text Available Let $F$ be a distribution in $\\mathcal{D'}$ and let $f$ be a locally summable function. The composition $F(f(x$ of $F$ and $f$ is said to exist and be equal to the distribution $h(x$ if the limit of the sequence $\\{ F_{n}(f(x\\}$ is equal to $h(x$, where $F_n(x =F(x*\\delta _n(x$ for $n=1,2, \\ldots$ and $\\{\\delta_n(x\\}$ is a certain regular sequence converging to the Dirac delta function. It is proved that the neutrix composition $ \\delta^{(s}[\\cosh^{-1} (x_+^{1/r}+1] $ exists and \\beqa \\delta^{(s}[\\cosh^{-1} (x_+^{1/r}+1] = - \\sum _{k=0} ^{M-1} \\sum_{i=0}^{kr+r} {k \\choose i}{(-1^{i+k}rc_{r,s,k} \\over (kr+rk!}\\delta ^{(k}(x, for $s =M-1,M, M+1,\\ldots$ and $r=1,2,\\ldots,$ where $$c_{r,s,k}=\\sum _{j=0}^{i} {i \\choose j}{ (-1^{kr+r-i}(2j-i^{s+1}\\over 2^{s+i+1} },$$ $M$ is the smallest integer for which $s-2r+1 < 2Mr$ and $r\\le s/(2M+2.$ Further results are also proved.

  12. THE NuSTAR X-RAY SPECTRUM OF HERCULES X-1: A RADIATION-DOMINATED RADIATIVE SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Michael T.; Wood, Kent S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Becker, Peter A. [Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030-4444 (United States); Gottlieb, Amy M.; Marcu-Cheatham, Diana M.; Pottschmidt, Katja [Department of Physics and Center for Space Science and Technology, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Fürst, Felix [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Hemphill, Paul B. [Center for Astrophysics and Space Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0424 (United States); Schwarm, Fritz-Walter; Wilms, Jörn [Dr. Karl-Remeis-Sternwarte and ECAP, Sternwartstr, 7, D-96049 Bamberg (Germany)

    2016-11-10

    We report on new spectral modeling of the accreting X-ray pulsar Hercules X-1. Our radiation-dominated radiative shock model is an implementation of the analytic work of Becker and Wolff on Comptonized accretion flows onto magnetic neutron stars. We obtain a good fit to the spin-phase-averaged 4–78 keV X-ray spectrum observed by the Nuclear Spectroscopic Telescope Array during a main-on phase of the Her X-1 35 day accretion disk precession period. This model allows us to estimate the accretion rate, the Comptonizing temperature of the radiating plasma, the radius of the magnetic polar cap, and the average scattering opacity parameters in the accretion column. This is in contrast to previous phenomenological models that characterized the shape of the X-ray spectrum, but could not determine the physical parameters of the accretion flow. We describe the spectral fitting details and discuss the interpretation of the accretion flow physical parameters.

  13. Investigation on spectroscopic parameters and molecular constants of BeS(X1Σ+) using MRCI theory

    International Nuclear Information System (INIS)

    Liu Hui; Xing Wei; Shi Deheng; Sun Jinfeng

    2012-01-01

    The potential energy curve (PEC) of BeS(X 1 Σ + ) molecule has been studied using MRCI approach with Davidson modification in conjunction with the cc-pV5Z basis set. Effects on the PECs by the core-valence correlation corrections and relativistic effects have been taken into account. The way to consider the relativistic effects is to use the second-order Douglas-Kroll Hamiltonian approximation. With the PEC including the core-valence correlation corrections and relativistic effects, the spectroscopic parameters of BeS(X 1 Σ + ) have been determined. These parameters are compared in detail with those of previous studies reported in the literature, and excellent agreement has been found between the available experimental data and the present ones. With the PEC corrected, the first 40 vibrational states for the non-rotating BeS are computed, and the vibrational level, inertial rotation and centrifugal distortion constants for each vibrational state are predicted. (authors)

  14. FAST TIMING ANALYSIS OF CYGNUS X-1 USING THE SPECTROMETER ON THE INTERNATIONAL GAMMA-RAY ASTROPHYSICS LABORATORY

    International Nuclear Information System (INIS)

    Cabanac, Clement; Roques, Jean-Pierre; Jourdain, Elisabeth

    2011-01-01

    We report for the first time the high-frequency analysis of Cyg X-1 up to hard X-ray using the spectrometer on International Gamma-Ray Astrophysics Laboratory (INTEGRAL). After analyzing the possible contribution from the background, and using the INTEGRAL archive from 2005 March to 2008 May, power density spectra were obtained up to 130 keV. First, we show that their overall shape is very similar to that observed at lower energies as they are well described by sets of Lorentzians. The strength of this fast variability (up to 40 Hz) does not drop at high energy since we show that it remains at ∼25% rms, even in the highest energy bands. Second, the hard X-ray variability patterns of Cyg X-1 are state dependent: the softer the spectrum (or the lower the hardness ratio), the lower the total fractional variability and the higher the typical frequencies observed. The strength of the total variability as a function of energy and state is then investigated. By comparison with simultaneous and published RXTE/Proportional Counter Array data, we show that in the hard state it remains quite constant in the 2-130 keV energy range. In the softer state it is also flat up to 50 keV and may increase at higher energy. The implications of this behavior on the models are then discussed.

  15. [Influence and mechanism of PinX1 gene on the chemotherapy sensitivity of nasopharyngeal carcinoma cells in response to Cisplatin].

    Science.gov (United States)

    Shen, Congxiang; Liu, Yanhui; Wen, Zhong; Yang, Keke; Li, Guanxue; Zhang, Shenhua; Zhang, Xinyu

    2015-06-23

    To explore the influence and mechanism of PinX1 gene on the chemotherapy sensitivity of nasopharyngeal carcinoma cells in response to Cisplatin. Transfected nasopharyngeal carcinoma 5-8F cell lines with pCDH-CMV-PinX1-copGFP vector constructed by lentivirus to generate Lenti-PinX1-5-8F cells containing PinX1 gene, using Lenti-Ctrl-5-8F cell (blank vector without PinX1 gene was used to transfect 5-8F cell lines) and 5-8F cell as controls. Expression of PinX1 gene, telomerase activity, the inhibition of cancer cells proliferation, combined anticancer effect with Cisplatin and the expression of lung resistance protein (LRP) and Bcl-2 were detected with fluorescent quantitation polymerase chain reaction (PCR), flow cytometry, thiazolyl blue (MTT) method, areole test, Western blot and drug sensitivity test, respectively, in four groups (Lenti-PinX1-5-8F cell + Cisplatin, Lenti-PinX1-5-8F cell, Cisplatin and 5-8F cell) so as to explore the influence and mechanism of PinX1 gene on the chemotherapy sensitivity of nasopharyngeal carcinoma cells in response to Cisplatin. The telomerase activity in Lenti-PinX1-5-8F cell (0.146 ± 0.004) was lower than those in the other two control cells (Lenti-Ctrl-5-8F cell: 0.967 ± 0.016, 5-8F cell: 1.000 ± 0.034, both P Cisplatin after lower level telomerase activity induced by PinX1 gene. Proliferation index (PI) (%) in Lenti-PinX1-5-8F cell + Cisplatin (14.39 ± 3.66) was also less than the other groups (Lenti-PinX1-5-8F cell, Cisplatin and 5-8F cell groups, 32.97 ± 3.00, 31.18 ± 4.24 and 47.19 ± 4.19, all P Cisplatin, which may be mediated by the down-regulation of telomerase activity and the inhibition of LRP and Bcl-2 gene in nasopharyngeal carcinoma cells.

  16. The formation of eccentric compact binary inspirals and the role of gravitational wave emission in binary-single stellar encounters

    International Nuclear Information System (INIS)

    Samsing, Johan; MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2014-01-01

    The inspiral and merger of eccentric binaries leads to gravitational waveforms distinct from those generated by circularly merging binaries. Dynamical environments can assemble binaries with high eccentricity and peak frequencies within the LIGO band. In this paper, we study binary-single stellar scatterings occurring in dense stellar systems as a source of eccentrically inspiraling binaries. Many interactions between compact binaries and single objects are characterized by chaotic resonances in which the binary-single system undergoes many exchanges before reaching a final state. During these chaotic resonances, a pair of objects has a non-negligible probability of experiencing a very close passage. Significant orbital energy and angular momentum are carried away from the system by gravitational wave (GW) radiation in these close passages, and in some cases this implies an inspiral time shorter than the orbital period of the bound third body. We derive the cross section for such dynamical inspiral outcomes through analytical arguments and through numerical scattering experiments including GW losses. We show that the cross section for dynamical inspirals grows with increasing target binary semi-major axis a and that for equal-mass binaries it scales as a 2/7 . Thus, we expect wide target binaries to predominantly contribute to the production of these relativistic outcomes. We estimate that eccentric inspirals account for approximately 1% of dynamically assembled non-eccentric merging binaries. While these events are rare, we show that binary-single scatterings are a more effective formation channel than single-single captures for the production of eccentrically inspiraling binaries, even given modest binary fractions.

  17. Photoluminescence of Eu{sup 2+}-doped CaMgSi{sub 2x}O{sub 6+2x} (1.00{<=}x{<=}1.20) phosphors in UV-VUV region

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhiya [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang Yuhua [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)], E-mail: wyh@lzu.edu.cn

    2008-03-15

    Alkaline-earth silicate phosphors CaMgSi{sub 2x}O{sub 6+2x}:Eu{sup 2+} (1.00{<=}x{<=}1.20) were prepared by traditional solid-state reaction. The phosphors showed an intense blue emission centered around 453 nm, with both 254 and 147 nm excitations. The host absorption below 200 nm in the excitation spectra consisted of two bands around 160 and 190 nm. The band around 160 nm was ascertained to be associated with the SiO{sub 4}-tetrahedra and MgO{sub 6}-polyhedra, and that around 190 nm was due to the CaO{sub 8}-polyhedra or some impurities. The incorporation of excess Si of less than 15% would not lead to formation of impurities and the results indicated that an appropriate Si excess could improve the Photoluminescence (PL) intensity in both ultraviolet (UV) and vacuum ultraviolet (VUV) regions.

  18. All-optical conversion scheme: Binary to quaternary and quaternary to binary number

    Science.gov (United States)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2009-04-01

    To achieve the inherent parallelism in optics a suitable number system and efficient encoding/decoding scheme for handling the data are very much essential. Binary number is accepted as the best representing number system in almost all types of existing electronic computers. But, binary number (0 and 1) is insufficient in respect to the demand of the coming generation. Multi-valued logic (with radix >2) can be viewed as an alternative approach to solve many problems in transmission, storage and processing of large amount of information in digital signal processing. Here, in this paper all-optical scheme for the conversion of binary to quaternary number and vice versa have been proposed and described. Simulation has also been done. In this all-optical scheme the numbers are represented by different discrete polarized state of light.

  19. Millimeter/submillimeter Spectroscopy of PH2CN ({\\tilde{X}} 1A') and CH3PH2 ({\\tilde{X}} 1A'): Probing the Complexity of Interstellar Phosphorus Chemistry

    Science.gov (United States)

    Halfen, D. T.; Clouthier, D. J.; Ziurys, L. M.

    2014-11-01

    Millimeter/submillimeter spectra of PH2CN ({\\tilde{X}} 1A') and CH3PH2 ({\\tilde{X}} 1A') have been recorded for the first time using direct absorption techniques. This work extends previous measurements of both molecules beyond the 10-50 GHz range. Both species were created in the presence of an AC discharge by the reaction of phosphorus vapor and either cyanogen and hydrogen (PH2CN) or methane (CH3PH2). Twelve rotational transitions of PH2CN were recorded over the region 305-422 GHz for asymmetry components Ka = 0 through 8. For CH3PH2, eight rotational transitions were measured from 210-470 GHz with Ka = 0 through 16; these spectra exhibited greater complexity due to the presence of internal rotation, which splits the Ka = 1, 2, and 3 asymmetry components into A and E states. Combined analyses of the millimeter/submillimeter and previous microwave data were performed for both molecules. For PH2CN, the spectra were fit with a Watson S-reduced asymmetric top Hamiltonian, resulting in more accurate rotational and centrifugal distortion constants. In the case of CH3PH2, an asymmetric top internal-rotation Hamiltonian was employed in the analysis, significantly improving the rotational and torsional parameters over previous microwave estimates. Searches for both molecules were subsequently conducted toward Sgr B2(N), using the 12 m telescope of the Arizona Radio Observatory (ARO). Neither species was identified, with abundance upper limits, relative to H2, of f (PH2CN/H2) PH2/H2) 2 and >200, respectively.

  20. Massive binaries in the vicinity of Sgr A*

    Energy Technology Data Exchange (ETDEWEB)

    Pfuhl, O.; Gillessen, S.; Genzel, R.; Eisenhauer, F.; Fritz, T. K.; Ott, T. [Max-Planck-Institut für Extraterrestrische Physik, D-85748 Garching (Germany); Alexander, T. [Faculty of Physics, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100 (Israel); Martins, F., E-mail: pfuhl@mpe.mpg.de [LUPM, Université Montpelier 2, CNRS, Place Eugéne Bataillon, F-34095, Montpellier (France)

    2014-02-20

    A long-term spectroscopic and photometric survey of the most luminous and massive stars in the vicinity of the supermassive black hole Sgr A* revealed two new binaries: a long-period Ofpe/WN9 binary, IRS 16NE, with a modest eccentricity of 0.3 and a period of 224 days, and an eclipsing Wolf-Rayet binary with a period of 2.3 days. Together with the already identified binary IRS 16SW, there are now three confirmed OB/WR binaries in the inner 0.2 pc of the Galactic center. Using radial velocity change upper limits, we were able to constrain the spectroscopic binary fraction in the Galactic center to F{sub SB}=0.30{sub −0.21}{sup +0.34} at a confidence level of 95%, a massive binary fraction close to that observed in dense clusters. The fraction of eclipsing binaries with photometric amplitudes Δm > 0.4 is F{sub EB}{sup GC}=3%±2%, which is consistent with local OB star clusters (F {sub EB} = 1%). Overall, the Galactic center binary fraction seems to be similar to the binary fraction in comparable young clusters.

  1. Rotational properties of the binary and non-binary populations in the Trans-Neptunian belt

    Science.gov (United States)

    Thirouin, Audrey; Noll, Keith S.; Ortiz Moreno, Jose Luis; Morales , Nicolas

    2014-11-01

    An exhaustive study about short-term variability as well as derived properties from lightcurves allowed us to draw some conclusions for the Trans-Neptunian belt binary population. Based on Maxwellian fit distributions of the spin rate, we suggested that the binary population rotates slower than the non-binary one. This slowing-down can be attributed to tidal effects between the satellite and the primary, as expected. We showed that no system in this work is tidally locked, but the primary despinning process may have already affected the primary rate (as well as the satellite rotational rate). We used the Gladman et al. (1996) formula to compute the time required to tidally lock the systems, but this formula is based on several assumptions and approximations that do not always hold. The computed times are reasonable in most cases and confirm that none of the systems is tidally locked, assuming that the satellite densities are low and have a high rigidity or have a higher dissipation than usually assumed. The rotational properties of small bodies provide information about important physical properties, such as shape, density, and cohesion (Pravec & Harris 2000; Holsapple 2001, 2004; Thirouin et al. 2010, 2012). For binaries it is also possible to derive several physical parameters of the system components, such as diameters of the primary/secondary and albedo under some assumptions. We compare our results as well as our technique for deriving this information from the lightcurve with other methods, such as: i) thermal or thermophysical modeling, ii) from the mutual orbit of the binary component, iii) from direct imaging or iv) from stellar occultation by Trans-Neptunian Objects (TNOs). Finally, by studying the specific angular momentum of the sample, we proposed possible formation models for several binary TNOs. In several cases, we obtained hints of the formation mechanism from the angular momentum, but for other cases we do not have enough information about the

  2. Binary Cepheids: Separations and Mass Ratios in 5 M ⊙ Binaries

    Science.gov (United States)

    Evans, Nancy Evans; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Karovska, Margarita; Tingle, Evan

    2013-10-01

    Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ~5 M ⊙—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ⊙. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ⊙ binaries have systematically shorter periods than do 1 M ⊙ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple. Based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained by the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

  3. BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M ☉ BINARIES

    International Nuclear Information System (INIS)

    Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.

    2013-01-01

    Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M ☉ —are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M ☉ . Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M ☉ binaries have systematically shorter periods than do 1 M ☉ stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple

  4. BINARY CEPHEIDS: SEPARATIONS AND MASS RATIOS IN 5 M {sub ☉} BINARIES

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Nancy Remage; Karovska, Margarita; Tingle, Evan [Smithsonian Astrophysical Observatory, MS 4, 60 Garden Street, Cambridge, MA 02138 (United States); Bond, Howard E. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Schaefer, Gail H. [The CHARA Array, Georgia State University, P.O. Box 3965, Atlanta, GA 30302-3965 (United States); Mason, Brian D., E-mail: nevans@cfa.harvard.edu, E-mail: heb11@psu.edu, E-mail: schaefer@chara-array.org [US Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420 (United States)

    2013-10-01

    Deriving the distribution of binary parameters for a particular class of stars over the full range of orbital separations usually requires the combination of results from many different observing techniques (radial velocities, interferometry, astrometry, photometry, direct imaging), each with selection biases. However, Cepheids—cool, evolved stars of ∼5 M {sub ☉}—are a special case because ultraviolet (UV) spectra will immediately reveal any companion star hotter than early type A, regardless of the orbital separation. We have used International Ultraviolet Explorer UV spectra of a complete sample of all 76 Cepheids brighter than V = 8 to create a list of all 18 Cepheids with companions more massive than 2.0 M {sub ☉}. Orbital periods of many of these binaries are available from radial-velocity studies, or can be estimated for longer-period systems from detected velocity variability. In an imaging survey with the Hubble Space Telescope Wide Field Camera 3, we resolved three of the companions (those of η Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods out to the long-period end of the distribution. Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations, orbital periods, and mass ratios. The distribution of orbital periods shows that the 5 M {sub ☉} binaries have systematically shorter periods than do 1 M {sub ☉} stars. Our data also suggest that the distribution of mass ratios depends on both binary separation and system multiplicity. The distribution of mass ratios as a function of orbital separation, however, does not depend on whether a system is a binary or a triple.

  5. Accuracy of binary black hole waveform models for aligned-spin binaries

    Science.gov (United States)

    Kumar, Prayush; Chu, Tony; Fong, Heather; Pfeiffer, Harald P.; Boyle, Michael; Hemberger, Daniel A.; Kidder, Lawrence E.; Scheel, Mark A.; Szilagyi, Bela

    2016-05-01

    Coalescing binary black holes are among the primary science targets for second generation ground-based gravitational wave detectors. Reliable gravitational waveform models are central to detection of such systems and subsequent parameter estimation. This paper performs a comprehensive analysis of the accuracy of recent waveform models for binary black holes with aligned spins, utilizing a new set of 84 high-accuracy numerical relativity simulations. Our analysis covers comparable mass binaries (mass-ratio 1 ≤q ≤3 ), and samples independently both black hole spins up to a dimensionless spin magnitude of 0.9 for equal-mass binaries and 0.85 for unequal mass binaries. Furthermore, we focus on the high-mass regime (total mass ≳50 M⊙ ). The two most recent waveform models considered (PhenomD and SEOBNRv2) both perform very well for signal detection, losing less than 0.5% of the recoverable signal-to-noise ratio ρ , except that SEOBNRv2's efficiency drops slightly for both black hole spins aligned at large magnitude. For parameter estimation, modeling inaccuracies of the SEOBNRv2 model are found to be smaller than systematic uncertainties for moderately strong GW events up to roughly ρ ≲15 . PhenomD's modeling errors are found to be smaller than SEOBNRv2's, and are generally irrelevant for ρ ≲20 . Both models' accuracy deteriorates with increased mass ratio, and when at least one black hole spin is large and aligned. The SEOBNRv2 model shows a pronounced disagreement with the numerical relativity simulation in the merger phase, for unequal masses and simultaneously both black hole spins very large and aligned. Two older waveform models (PhenomC and SEOBNRv1) are found to be distinctly less accurate than the more recent PhenomD and SEOBNRv2 models. Finally, we quantify the bias expected from all four waveform models during parameter estimation for several recovered binary parameters: chirp mass, mass ratio, and effective spin.

  6. COSMIC probes into compact binary formation and evolution

    Science.gov (United States)

    Breivik, Katelyn

    2018-01-01

    The population of compact binaries in the galaxy represents the final state of all binaries that have lived up to the present epoch. Compact binaries present a unique opportunity to probe binary evolution since many of the interactions binaries experience can be imprinted on the compact binary population. By combining binary evolution simulations with catalogs of observable compact binary systems, we can distill the dominant physical processes that govern binary star evolution, as well as predict the abundance and variety of their end products.The next decades herald a previously unseen opportunity to study compact binaries. Multi-messenger observations from telescopes across all wavelengths and gravitational-wave observatories spanning several decades of frequency will give an unprecedented view into the structure of these systems and the composition of their components. Observations will not always be coincident and in some cases may be separated by several years, providing an avenue for simulations to better constrain binary evolution models in preparation for future observations.I will present the results of three population synthesis studies of compact binary populations carried out with the Compact Object Synthesis and Monte Carlo Investigation Code (COSMIC). I will first show how binary-black-hole formation channels can be understood with LISA observations. I will then show how the population of double white dwarfs observed with LISA and Gaia could provide a detailed view of mass transfer and accretion. Finally, I will show that Gaia could discover thousands black holes in the Milky Way through astrometric observations, yielding view into black-hole astrophysics that is complementary to and independent from both X-ray and gravitational-wave astronomy.

  7. CORONA, JET, AND RELATIVISTIC LINE MODELS FOR SUZAKU/RXTE/CHANDRA-HETG OBSERVATIONS OF THE CYGNUS X-1 HARD STATE

    International Nuclear Information System (INIS)

    Nowak, Michael A.; Trowbridge, Sarah N.; Davis, John E.; Hanke, Manfred; Wilms, Joern; Markoff, Sera B.; Maitra, Dipankar; Tramper, Frank; Pottschmidt, Katja; Coppi, Paolo

    2011-01-01

    Using Suzaku and the Rossi X-ray Timing Explorer (RXTE), we have conducted a series of four simultaneous observations of the galactic black hole candidate Cyg X-1 in what were historically faint and spectrally hard 'low states'. Additionally, all of these observations occurred near superior conjunction with our line of sight to the X-ray source passing through the dense phases of the 'focused wind' from the mass donating secondary. One of our observations was also simultaneous with observations by the Chandra-High Energy Transmission Grating (HETG). These latter spectra are crucial for revealing the ionized absorption due to the secondary's focused wind. Such absorption is present and must be accounted for in all four spectra. These simultaneous data give an unprecedented view of the 0.8-300 keV spectrum of Cyg X-1, and hence bear upon both corona and X-ray emitting jet models of black hole hard states. Three models fit the spectra well: coronae with thermal or mixed thermal/non-thermal electron populations and jets. All three models require a soft component that we fit with a low temperature disk spectrum with an inner radius of only a few tens of GM/c 2 . All three models also agree that the known spectral break at 10 keV is not solely due to the presence of reflection, but each gives a different underlying explanation for the augmentation of this break. Thus, whereas all three models require that there is a relativistically broadened Fe line, the strength and inner radius of such a line is dependent upon the specific model, thus making premature line-based estimates of the black hole spin in the Cyg X-1 system. We look at the relativistic line in detail, accounting for the narrow Fe emission and ionized absorption detected by HETG. Although the specific relativistic parameters of the line are continuum dependent, none of the broad line fits allow for an inner disk radius that is >40 GM/c 2 .

  8. "Binary" and "non-binary" detection tasks: are current performance measures optimal?

    Science.gov (United States)

    Gur, David; Rockette, Howard E; Bandos, Andriy I

    2007-07-01

    We have observed that a very large fraction of responses for several detection tasks during the performance of observer studies are in the extreme ranges of lower than 11% or higher than 89% regardless of the actual presence or absence of the abnormality in question or its subjectively rated "subtleness." This observation raises questions regarding the validity and appropriateness of using multicategory rating scales for such detection tasks. Monte Carlo simulation of binary and multicategory ratings for these tasks demonstrate that the use of the former (binary) often results in a less biased and more precise summary index and hence may lead to a higher statistical power for determining differences between modalities.

  9. Measurement of the energetics of metal film growth on a semiconductor: Ag/ Si(100)-2x1

    DEFF Research Database (Denmark)

    Starr, D.E.; Ranney, J.T.; Larsen, Jane Hvolbæk

    2001-01-01

    The first direct calorimetric measurements of the energetics of metal film growth on a semiconductor surface are presented. The heat of adsorption of Ag on Si(100)-(2 x 1) at 300 K decreases from similar to 347 to 246 kJ/mol with coverage in the first monolayer (ML) due to overlap of substrate...... strain from nearby Ag islands. It then rises quickly toward the bulk sublimation enthalpy (285 kJ/mol) as 3D particles grow. A wetting layer grows to 1.0 ML, but is metastable above similar to0.55 ML and dewets when kinetics permit. This may be common when adsorbate islands induce a large strain...

  10. Analysis of the dimerized Sb/Si(001)-(2x1) surface by x-ray standing waves

    International Nuclear Information System (INIS)

    Lyman, P.F.; Qian, Y.; Bedzyk, M.J.

    1994-12-01

    X-ray standing wave measurements were undertaken to study the bonding position of Sb adatoms on the Sb-saturated Si(001)-(2x1) surface. Using the (004) and (022) Bragg reflections, the authors find that the Sb atoms form dimers, and that the center of the Sb ad-dimers lies 1.64 angstrom above the bulk-like Si(004) surface atomic plane. These in-plane results are compared to two structural models consisting of dimers whose bonds are parallel to the surface plane and whose centers are either shifted or unshifted (parallel to the dimer bond direction) relative to the underlying substrate planes. The authors thus find two special cases consistent with these data: one with symmetric (unshifted) dimers having a dimer bond length of 2.81 angstrom, and the other with midpoint-shifted dimers, having a bond length of 2.88 angstrom and a lateral shift of 0.21 angstrom

  11. The crystal structure of a new ternary antimonide: TmCu4-xSb2 (x 1.065)

    International Nuclear Information System (INIS)

    Fedyna, L.O.; Bodak, O.I.; Fedorchuk, A.O.; Tokaychuk, Ya.O.

    2005-01-01

    The crystal structure of the new ternary compound TmCu 4-x Sb 2 (x 1.065) was determined by direct methods from X-ray powder data (diffractometer DRON-3M, Cu Kα-radiation). It crystallizes with the orthorhombic structure type ErFe 4 Ge 2 (low-temperature modification) and is the first representative of this structure type among known antimonides: space group Pnnm, Pearson code oP14-2.13, a = 7.00565(6) A, b = 7.83582(6) A, c = 4.25051(3) A, Z = 2. Investigated structure is an orthorhombically deformed derivative of the ZrFe 4 Si 2 structure type

  12. Control of in-plane orientation of phthalocyanine molecular columns using vicinal Si(001)-(2x1)-H

    International Nuclear Information System (INIS)

    Nakamura, Masakazu; Matsunobe, Takeshi; Tokumoto, Hiroshi

    2001-01-01

    In-plane crystal orientation of copper phthalocyanine (CuPc) films formed by organic molecular-beam epitaxy have been successfully controlled by using vicinal Si(001)-(2x1)-H as a substrate, containing atomic steps of an approximately 4 nm period. A continuous film was grown at 60 degree C and the film thickness ranged between 5 and 8 molecular layers. By observing a frictional force image of the film, 90% of the molecular columns were found to align across the substrate step rows. The preferential orientation is considered to be induced by artificial surface lattices, which result from the striped effective contact area between the rigid CuPc crystals and the stair-like surfaces. The anisotropic optical properties of the film have been also confirmed by polarized reflection measurements. [copyright] 2001 American Institute of Physics

  13. Eclipsing binaries observed with the WIRE satellite I. Discovery and photometric analysis of the new bright A0 IV eclipsing binary psi centauri

    DEFF Research Database (Denmark)

    Bruntt, Hans; Southworth, J.; Penny, A. J.

    2006-01-01

    Stars: fundamental parameters, binaries: close, eclipsing, techniques: photometric Udgivelsesdato: Sep.......Stars: fundamental parameters, binaries: close, eclipsing, techniques: photometric Udgivelsesdato: Sep....

  14. Observational test for the existence of a rotating black hole in Cyg X-1. [Gravitatinal effects, polarization properties

    Energy Technology Data Exchange (ETDEWEB)

    Stark, R F; Connors, P A [Oxford Univ. (UK). Dept. of Astrophysics

    1977-03-31

    It is stated that the degree and plane of linear polarisation of the radiation from Cyg X-1 are being investigated by X-ray satellite experiments. This radiation can be explained as coming from an accretion disk around a black hole, the polarisation of the X-rays being due to electron scattering in the hotter inner regions of the disk. Existing predictions of the polarisation properties, as a function of energy, have been based on a Newtonian approximation, thus neglecting gravitational effects on the rays as they propagate from the surface of the disk to an observer at infinity. Preliminary results are here given of a full general relativistic calculation that shows that gravitational effects completely alter the polarisation properties, and provide a sensitive test of the existence of a black hole. It is found that for a rapidly rotating black hole the general relativistic effects on the polarisation properties are an order of magnitude greater than for a slowly rotating black hole, or for a neutron star. The degree of linear polarisation of the rays as they leave the disk will also differ from the Newtonian value, and gravitational bending of the light will alter the angle at which a ray leaves the surface of the disk. The large general relativistic variation of the polarisation plane with energy is illustrated graphically. The very large general relativistic rotations in the plane of polarisation provide an opportunity for testing the black hole hypothesis for Cyg X-1. In order to observe these effects X-ray satellite experiments will be required with more sensitive polarimetry across a wider energy range than is available at present.

  15. Structure determination of Ga As (110) p (1 x 1) - Sb using scanned-energy photoelectron diffraction

    International Nuclear Information System (INIS)

    Ascolani, H.; Asensio, M.C.; Fritzsche, W.

    1996-01-01

    Photoelectron diffraction (PD) in the scanned-energy mode has proven to be a powerfull tool for structural determination of the first few surface layers. The scanned-energy mode involves the measurement of the intensity of photoelectrons emitted from a core level as a function of the incident photon energy for different emission directions. The atom specificity of PD allows the investigation of the local structure of adsorbed atoms without interference of the substrate. In addition, if a measurable chemical shift exists, this technique is also able to discriminate between atoms of the same species adsorbed in inequivalent sites. The Ga As (110) p (1x1)-Sb (1 ML) surface represents a prototype system to study atom adsorption on III-V semiconductors. The epitaxial continued layer structure (ECLS) is generally accepted as the geometry corresponding to this surface, although some authors have claimed that the p 3 model forms a stable geometry equivalent to the ECLS, and that it provides an equally good description of their experimental results. So far, the conclusions about the atomic structure of this surface had been derived on the basis of indirect methods. This work exploits to the utmost the possibilities of analysis offered by the scanned-energy PD technique, namely, chemical shift analysis and direct inversion. The energy spectrum of Sb-4d photoelectrons emitted from the Ga As (110)-p (1x1) Sb surface has two chemically-shifted components. We have inverted the scanned-energy photoelectron diffraction data corresponding to these two components to obtain the positions of the Ga and As atoms which are nearest neighbors of two inequivalent Sb atoms. Our results contradict various models proposed for this surface and are consistent only with the ECLS. For a more detailed atomic structure determination, the best fit between experiment and multiple-scattering calculations was determined by a trial-and-error procedure. (author)

  16. A Multiwavelength Study of Cygnus X-1: The First Mid-Infrared Spectroscopic Detection of Compact Jets

    Science.gov (United States)

    Rahoui, Farid; Lee, Julia C.; Heinz, Sebastian; Hines, Dean C.; Pottschmidt, Katja; Wilms, Joern

    2011-01-01

    We report on a Spitzer/IRS (mid-infrared), RXTE /PCA+HEXTE (X-ray), and Ryle (radio) simultaneous multi-wavelength study of the micro quasar Cygnus X-I, which aimed at an investigation of the origin of its mid-infrared emission. Compact jets were present in two out of three observations, and we show that they strongly contribute to the mid-infrared continuum. During the first observation, we detect the spectral break - where the transition from the optically thick to the optically thin regime takes place - at about 2.9 x 10(exp 13) Hz. We then show that the jet's optically thin synchrotron emission accounts for the Cygnus X-1's emission beyond 400 keY, although it cannot alone explain its 3-200 keV continuum. A compact jet was also present during the second observation, but we do not detect the break, since it has likely shifted to higher frequencies. In contrast, the compact jet was absent during the last observation, and we show that the 5-30 micron mid-infrared continuum of Cygnus X-I stems from the blue supergiant companion star HD 226868. Indeed, the emission can then be understood as the combination of the photospheric Raleigh-Jeans tail and the bremsstrahlung from the expanding stellar wind. Moreover, the stellar wind is found to be clumpy, with a filling factor f(sub infinity) approx.= 0.09-0.10. Its bremsstrahlung emission is likely anti-correlated to the soft X-ray emission, suggesting an anticorrelation between the mass-loss and mass-accretion rates. Nevertheless, we do not detect any mid-infrared spectroscopic evidence of interaction between the jets and the Cygnus X-1's environment and/or companion star's stellar wind.

  17. Binary pairs of supermassive black holes - Formation in merging galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Valtaoja, L.; Valtonen, M.J.; Byrd, G.G. (Turku Univ. (Finland); Alabama Univ., Tuscaloosa (USA))

    1989-08-01

    A process in which supermassive binary blackholes are formed in nuclei of supergiant galaxies due to galaxy mergers is examined. There is growing evidence that mergers of galaxies are common and that supermassive black holes in center of galaxies are also common. Consequently, it is expected that binary black holes should arise in connection with galaxy mergers. The merger process in a galaxy modeled after M87 is considered. The capture probability of a companion is derived as a function of its mass. Assuming a correlation between the galaxy mass and the blackholes mass, the expected mass ratio in binary black holes is calculated. The binary black holes formed in this process are long lived, surviving longer than the Hubble time unless they are perturbed by black holes from successive mergers. The properties of these binaries agree with Gaskell's (1988) observational work on quasars and its interpretation in terms of binary black holes. 39 refs.

  18. Formation and Evolution of Binary Asteroids

    Science.gov (United States)

    Walsh, K. J.; Jacobson, S. A.

    Satellites of asteroids have been discovered in nearly every known small-body population, and a remarkable aspect of the known satellites is the diversity of their properties. They tell a story of vast differences in formation and evolution mechanisms that act as a function of size, distance from the Sun, and the properties of their nebular environment at the beginning of solar system history and their dynamical environment over the next 4.5 G.y. The mere existence of these systems provides a laboratory to study numerous types of physical processes acting on asteroids, and their dynamics provide a valuable probe of their physical properties otherwise possible only with spacecraft. Advances in understanding the formation and evolution of binary systems have been assisted by (1) the growing catalog of known systems, increasing from 33 to ~250 between the Merline et al. (2002) chapter in Asteroids III and now; (2) the detailed study and long-term monitoring of individual systems such as 1999 KW4 and 1996 FG3, (3) the discovery of new binary system morphologies and triple systems, (4) and the discovery of unbound systems that appear to be end-states of binary dynamical evolutionary paths. Specifically for small bodies (diameter smaller than 10 km), these observations and discoveries have motivated theoretical work finding that thermal forces can efficiently drive the rotational disruption of small asteroids. Long-term monitoring has allowed studies to constrain the system's dynamical evolution by the combination of tides, thermal forces, and rigid-body physics. The outliers and split pairs have pushed the theoretical work to explore a wide range of evolutionary end-states.

  19. The Fate of Neutron Star Binary Mergers

    Energy Technology Data Exchange (ETDEWEB)

    Piro, Anthony L. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Giacomazzo, Bruno [Physics Department, University of Trento, via Sommarive 14, I-38123 Trento (Italy); Perna, Rosalba, E-mail: piro@carnegiescience.edu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States)

    2017-08-01

    Following merger, a neutron star (NS) binary can produce roughly one of three different outcomes: (1) a stable NS, (2) a black hole (BH), or (3) a supramassive, rotationally supported NS, which then collapses to a BH following angular momentum losses. Which of these fates occur and in what proportion has important implications for the electromagnetic transient associated with the mergers and the expected gravitational wave (GW) signatures, which in turn depend on the high density equation of state (EOS). Here we combine relativistic calculations of NS masses using realistic EOSs with Monte Carlo population synthesis based on the mass distribution of NS binaries in our Galaxy to predict the distribution of fates expected. For many EOSs, a significant fraction of the remnants are NSs or supramassive NSs. This lends support to scenarios in which a quickly spinning, highly magnetized NS may be powering an electromagnetic transient. This also indicates that it will be important for future GW observatories to focus on high frequencies to study the post-merger GW emission. Even in cases where individual GW events are too low in signal to noise to study the post merger signature in detail, the statistics of how many mergers produce NSs versus BHs can be compared with our work to constrain the EOS. To match short gamma-ray-burst (SGRB) X-ray afterglow statistics, we find that the stiffest EOSs are ruled out. Furthermore, many popular EOSs require a significant fraction of ∼60%–70% of SGRBs to be from NS–BH mergers rather than just binary NSs.

  20. Electronic band structures of binary skutterudites

    International Nuclear Information System (INIS)

    Khan, Banaras; Aliabad, H.A. Rahnamaye; Saifullah; Jalali-Asadabadi, S.; Khan, Imad; Ahmad, Iftikhar

    2015-01-01

    The electronic properties of complex binary skutterudites, MX 3 (M = Co, Rh, Ir; X = P, As, Sb) are explored, using various density functional theory (DFT) based theoretical approaches including Green's Function (GW) as well as regular and non-regular Tran Blaha modified Becke Jhonson (TB-mBJ) methods. The wide range of calculated bandgap values for each compound of this skutterudites family confirm that they are theoretically as challenging as their experimental studies. The computationally expensive GW method, which is generally assume to be efficient in the reproduction of the experimental bandgaps, is also not very successful in the calculation of bandgaps. In this article, the issue of the theoretical bandgaps of these compounds is resolved by reproducing the accurate experimental bandgaps, using the recently developed non-regular TB-mBJ approach, based on DFT. The effectiveness of this technique is due to the fact that a large volume of the binary skutterudite crystal is empty and hence quite large proportion of electrons lie outside of the atomic spheres, where unlike LDA and GGA which are poor in the treatment of these electrons, this technique properly treats these electrons and hence reproduces the clear electronic picture of these compounds. - Highlights: • Theoretical and experimental electronic band structures of binary skutterudites are reviewed. • The literature reveals that none of the existing theoretical results are consistent with the experiments. • GW, regular and non-regular TB-mBJ methods are used to reproduce the correct results. • The GW and regular TB-mBJ results are better than the available results in literature. • However, non-regular TB-mBJ reproduces the correct experimental band structures

  1. Green binary and phase shifting mask

    Science.gov (United States)

    Shy, S. L.; Hong, Chao-Sin; Wu, Cheng-San; Chen, S. J.; Wu, Hung-Yu; Ting, Yung-Chiang

    2009-12-01

    SixNy/Ni thin film green mask blanks were developed , and are now going to be used to replace general chromium film used for binary mask as well as to replace molydium silicide embedded material for AttPSM for I-line (365 nm), KrF (248 nm), ArF (193 nm) and Contact/Proximity lithography. A bilayer structure of a 1 nm thick opaque, conductive nickel layer and a SixNy layer is proposed for binary and phase-shifting mask. With the good controlling of plasma CVD of SixNy under silane (50 sccm), ammonia (5 sccm) and nitrogen (100 sccm), the pressure is 250 mTorr. and RF frequency 13.56 MHz and power 50 W. SixNy has enough deposition latitude to meet the requirements as an embedded layer for required phase shift 180 degree, and the T% in 193, 248 and 365 nm can be adjusted between 2% to 20% for binary and phase shifting mask usage. Ni can be deposited by E-gun, its sheet resistance Rs is less than 1.435 kΩ/square. Jeol e-beam system and I-line stepper are used to evaluate these thin film green mask blanks, feature size less than 200 nm half pitch pattern and 0.558 μm pitch contact hole can be printed. Transmission spectrums of various thickness of SixNy film are inspected by using UV spectrometer and FTIR. Optical constants of the SixNy film are measured by n & k meter and surface roughness is inspected by using Atomic Force Microscope (AFM).

  2. Binary Classification Method of Social Network Users

    Directory of Open Access Journals (Sweden)

    I. A. Poryadin

    2017-01-01

    Full Text Available The subject of research is a binary classification method of social network users based on the data analysis they have placed. Relevance of the task to gain information about a person by examining the content of his/her pages in social networks is exemplified. The most common approach to its solution is a visual browsing. The order of the regional authority in our country illustrates that its using in school education is needed. The article shows restrictions on the visual browsing of pupil’s pages in social networks as a tool for the teacher and the school psychologist and justifies that a process of social network users’ data analysis should be automated. Explores publications, which describe such data acquisition, processing, and analysis methods and considers their advantages and disadvantages. The article also gives arguments to support a proposal to study the classification method of social network users. One such method is credit scoring, which is used in banks and credit institutions to assess the solvency of clients. Based on the high efficiency of the method there is a proposal for significant expansion of its using in other areas of society. The possibility to use logistic regression as the mathematical apparatus of the proposed method of binary classification has been justified. Such an approach enables taking into account the different types of data extracted from social networks. Among them: the personal user data, information about hobbies, friends, graphic and text information, behaviour characteristics. The article describes a number of existing methods of data transformation that can be applied to solve the problem. An experiment of binary gender-based classification of social network users is described. A logistic model obtained for this example includes multiple logical variables obtained by transforming the user surnames. This experiment confirms the feasibility of the proposed method. Further work is to define a system

  3. Electronic band structures of binary skutterudites

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Banaras [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan); Aliabad, H.A. Rahnamaye [Department of Physics, Hakim Sabzevari University, Sabzevar (Iran, Islamic Republic of); Saifullah [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan); Jalali-Asadabadi, S. [Department of Physics, Faculty of Science, University of Isfahan (UI), 81744 Isfahan (Iran, Islamic Republic of); Khan, Imad [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan); Ahmad, Iftikhar, E-mail: ahma5532@gmail.com [Center for Computational Materials Science, University of Malakand, Chakdara (Pakistan); Department of Physics, University of Malakand, Chakdara (Pakistan)

    2015-10-25

    The electronic properties of complex binary skutterudites, MX{sub 3} (M = Co, Rh, Ir; X = P, As, Sb) are explored, using various density functional theory (DFT) based theoretical approaches including Green's Function (GW) as well as regular and non-regular Tran Blaha modified Becke Jhonson (TB-mBJ) methods. The wide range of calculated bandgap values for each compound of this skutterudites family confirm that they are theoretically as challenging as their experimental studies. The computationally expensive GW method, which is generally assume to be efficient in the reproduction of the experimental bandgaps, is also not very successful in the calculation of bandgaps. In this article, the issue of the theoretical bandgaps of these compounds is resolved by reproducing the accurate experimental bandgaps, using the recently developed non-regular TB-mBJ approach, based on DFT. The effectiveness of this technique is due to the fact that a large volume of the binary skutterudite crystal is empty and hence quite large proportion of electrons lie outside of the atomic spheres, where unlike LDA and GGA which are poor in the treatment of these electrons, this technique properly treats these electrons and hence reproduces the clear electronic picture of these compounds. - Highlights: • Theoretical and experimental electronic band structures of binary skutterudites are reviewed. • The literature reveals that none of the existing theoretical results are consistent with the experiments. • GW, regular and non-regular TB-mBJ methods are used to reproduce the correct results. • The GW and regular TB-mBJ results are better than the available results in literature. • However, non-regular TB-mBJ reproduces the correct experimental band structures.

  4. Vapour pressure and excess Gibbs free energy of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane at temperature of 182.33K

    International Nuclear Information System (INIS)

    Lobo, L.Q.; Ferreira, A.G.M.; Fonseca, I.M.A.; Senra, A.M.P.

    2006-01-01

    The vapour pressure of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane was measured at T=182.33K covering most of the composition range. The excess Gibbs free energy of these mixtures has been derived from the measurements made. For the equimolar mixtures G m E (x 1 =0.5)=(835.5+/-5.8)J.mol -1 for (H 2 S+C 2 H 6 ) (820.1+/-2.4)J.mol -1 for (H 2 S+C 3 H 8 ), and (818.6+/-0.9)J.mol -1 for (H 2 S+n-C 4 H 10 ). The binary mixtures of H 2 S with ethane and with propane exhibit azeotropes, but that with n-butane does not

  5. Diffusive flux of energy in binary mixtures

    International Nuclear Information System (INIS)

    Sampaio, R.S.

    1976-04-01

    The diffusive flux of energy j tilde is studied through the reduced diffusive flux of energy K tilde, which obeys equations of the form: sim(delta K tilde/delta grad rho sub(α))= sim(delta K tilde/delta grad theta)=0. By a representation theorem, herein proved, is obtained a general representation for K tilde which is simplified, for the case of binary mixtures, using the principle of objectivity. Some consequences of this representation are discussed such as the symmetry of the partial stresses T 1 tilde and T 2 tilde and the difference between the normal stresses [pt

  6. Energy transfer in contact binary systems

    International Nuclear Information System (INIS)

    Robertson, J.A.

    1980-01-01

    A simple model for the transfer of energy by steady circulation within the envelope of a contact binary system is presented. The model describes the fully compressible, two-dimensional flow of a perfect gas within a rectangular region in a uniform gravitational field. The region is heated non-uniformly from below. Coriolis forces are neglected but the interaction of the circulation with convection is discussed briefly. Numerical solutions of the linearized equations of the problem are discussed in detail, and the results of some non-linear calculations are also presented. The influence of alternative boundary conditions is examined. (author)

  7. Burnup characteristics of binary breeder reactors

    International Nuclear Information System (INIS)

    Dias, A.F.; Nascimento, J.A. do; Ishiguro, Y.

    1983-01-01

    Burnup calculations of a binary breeder reactor have been done for two cases of fueling. In one case the U 233 /TH fueled inner core and the Pu/U-fueled outer core have the same number of fuel assemblies. In the other case two outermost rings in the inner core are Pu/U-fueled. The second case is considered for an initial phase of thorim cycle introduction when the supply of U 233 could be limited. Results show an efficient breeding on the thorium cycle in both cases. (Author) [pt

  8. Disordered multihyperuniformity derived from binary plasmas

    Science.gov (United States)

    Lomba, Enrique; Weis, Jean-Jacques; Torquato, Salvatore

    2018-01-01

    Disordered multihyperuniform many-particle systems are exotic amorphous states that allow exquisite color sensing capabilities due to their anomalous suppression of density fluctuations for distinct subsets of particles, as recently evidenced in photoreceptor mosaics in avian retina. Motivated by this biological finding, we present a statistical-mechanical model that rigorously achieves disordered multihyperuniform many-body systems by tuning interactions in binary mixtures of nonadditive hard-disk plasmas. We demonstrate that multihyperuniformity competes with phase separation and stabilizes a clustered phase. Our work provides a systematic means to generate disordered multihyperuniform solids, and hence lays the groundwork to explore their potentially unique photonic, phononic, electronic, and transport properties.

  9. NONLINEAR TIDES IN CLOSE BINARY SYSTEMS

    International Nuclear Information System (INIS)

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-01-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' ∼> 10-100 M ⊕ at orbital periods P ≈ 1-10 days. The nearly static 'equilibrium' tidal distortion is, however, stable to parametric resonance except for solar binaries with P ∼ 3 [P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the standard three-wave parametric instability. These are local instabilities viewed through the lens of global analysis; the coherent global growth rate follows local rates in the regions where the shear is strongest. In solar-type stars, the dynamical tide is unstable to this collective version of the parametric instability for even sub-Jupiter companion masses with P ∼< a month. (4) Independent of the parametric instability, the dynamical and equilibrium tides excite a wide range of stellar p-modes and g-modes by nonlinear inhomogeneous forcing

  10. Dynamic Binary Modification Tools, Techniques and Applications

    CERN Document Server

    Hazelwood, Kim

    2011-01-01

    Dynamic binary modification tools form a software layer between a running application and the underlying operating system, providing the powerful opportunity to inspect and potentially modify every user-level guest application instruction that executes. Toolkits built upon this technology have enabled computer architects to build powerful simulators and emulators for design-space exploration, compiler writers to analyze and debug the code generated by their compilers, software developers to fully explore the features, bottlenecks, and performance of their software, and even end-users to extend

  11. X-ray binaries, part 1

    International Nuclear Information System (INIS)

    Hammerschlag-Hensberge, G.C.M.J.

    1977-01-01

    Optical observations of X-ray binaries and their interpretation are described. A number of early-type stars which are identified as companions of X-ray sources are photometrically and spectroscopically observed. The spectra were obtained with the coude spectrograph attached to the 1.5 m telescope of the European Southern Observatory, La Silla, Chile. Registrations of the spectra were made with the Faul-Coradi microphotometer of the Observatory at Utrecht. To study radial velocity variations, the positions of the spectral lines were measured with the Grant comparator of the University of Groningen

  12. Is the Coma cluster binary dominated?

    International Nuclear Information System (INIS)

    The, L.S.; White, S.D.M.

    1990-01-01

    It is investigated whether the model of an expanding cluster dominated by a massive binary galaxy, first suggested by Valtonen and Byrd (1979), is consistent with optical data on the surface density and velocity dispersion of the Coma cluster. The evolution of this model is simulated for a wide variety of initial conditions. It is found that galaxy counts in the model can be made to agree with observation, but that the observed velocity dispersion profile cannot be reproduced. A number of other arguments suggest that the central galaxies in Coma cannot be as massive as required by the model. This model is not a viable representation of the Coma cluster. 25 refs

  13. A unified kinetic approach to binary nucleation

    Energy Technology Data Exchange (ETDEWEB)

    Kevrekidis, P.G. [Department of Physics, Rutgers University, 136 Frelinghuysen Road]|[E.O.H.S.I., Rutgers University]|[UMDNJ, 170 Frelinghuysen Road, Piscataway, New Jersey 08854-8019 (United States); Lazaridis, M. [Norwegian Institute for Air Research (NILU), Instittutvein 18, P. O. Box 100, N-2007 Kjeller (Norway); Drossinos, Y. [European Commission, Joint Research Centre, I-21020 Ispra (Vatican City State, Holy See) (Italy); Georgopoulos, P.G. [E.O.H.S.I., Rutgers University]|[UMDNJ, 170 Frelinghuysen Road, Piscataway, New Jersey 08854 (United States)

    1999-11-01

    Two different methods to calculate the steady-state nucleation rate in heteromolecular systems proposed by Stauffer (1976) and Langer (1969) are analyzed. Their mathematical equivalence is explicitly demonstrated, thereby obtaining a generic expression for the rate of binary nucleation. Its numerical evaluation does not entail rotation of the coordinate system at the saddle point, but it only requires data in the natural coordinate system of number fluctuations, namely molecular impingement rates, the droplet free energy and its second order derivatives at the saddle point, and the total density of condensible vapors. {copyright} {ital 1999 American Institute of Physics.}

  14. in Binary Liquid Mixtures of Ethyl benzoate

    Directory of Open Access Journals (Sweden)

    Shaik Babu

    2012-01-01

    Full Text Available Ultrasonic velocity is measured at 2MHz frequency in the binary mixtures of Ethyl Benzoate with 1-Propanol, 1-Butanol, 1-Pentanol and theoretical values of ultrasonic velocity have been evaluated at 303K using Nomoto's relation, Impedance relation, Ideal mixture relation, Junjie's method and free length theory. Theoretical values are compared with the experimental values and the validity of the theories is checked by applying the chi-square test for goodness of fit and by calculating the average percentage error (APE. A good agreement has been found between experimental and Nomoto’s ultrasonic velocity.

  15. Clonal sets of a binary relation

    Science.gov (United States)

    Zedam, Lemnaouar; Pérez-Fernández, Raúl; Bouremel, Hassane; De Baets, Bernard

    2018-05-01

    In a recent paper, we have introduced the notion of clone relation of a given binary relation. Intuitively, two elements are said to be "clones" if they are related in the same way w.r.t. every other element. In this paper, we generalize this notion from pairs of elements to sets of elements of any cardinality, resulting in the introduction of clonal sets. We investigate the most important properties of clonal sets, paying particular attention to the introduction of the clonal closure operator, to the analysis of the (lattice) structure of the set of clonal sets and to a distance metric expressing how close two elements are to being clones.

  16. Pycnonuclear reaction rates for binary ionic mixtures

    Science.gov (United States)

    Ichimaru, S.; Ogata, S.; Van Horn, H. M.

    1992-01-01

    Through a combination of compositional scaling arguments and examinations of Monte Carlo simulation results for the interparticle separations in binary-ionic mixture (BIM) solids, we have derived parameterized expressions for the BIM pycnonuclear rates as generalizations of those in one-component solids obtained previously by Salpeter and Van Horn and by Ogata et al. We have thereby discovered a catalyzing effect of the heavier elements, which enhances the rates of reactions among the lighter elements when the charge ratio exceeds a critical value of approximately 2.3.

  17. HD 161306: a radiatively interacting Be binary?

    Czech Academy of Sciences Publication Activity Database

    Koubský, Pavel; Kotková, Lenka; Kraus, Michaela; Yang, S.; Šlechta, Miroslav; Harmanec, P.; Wolf, M.; Votruba, Viktor; Kubát, Jiří; Kubátová, Brankica; Niemczura, E.; Škoda, Petr

    2014-01-01

    Roč. 567, July (2014), A57/1-A57/4 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GA14-21373S; GA MŠk LG14026 Grant - others:ESA(XE) ESA- PECS project no. 98058; GA ČR(CZ) GAP209/10/0715 Program:GA Institutional support: RVO:67985815 Keywords : binaries: spectroscopic * stars: emission-line * Be: stars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  18. Automatic target detection using binary template matching

    Science.gov (United States)

    Jun, Dong-San; Sun, Sun-Gu; Park, HyunWook

    2005-03-01

    This paper presents a new automatic target detection (ATD) algorithm to detect targets such as battle tanks and armored personal carriers in ground-to-ground scenarios. Whereas most ATD algorithms were developed for forward-looking infrared (FLIR) images, we have developed an ATD algorithm for charge-coupled device (CCD) images, which have superior quality to FLIR images in daylight. The proposed algorithm uses fast binary template matching with an adaptive binarization, which is robust to various light conditions in CCD images and saves computation time. Experimental results show that the proposed method has good detection performance.

  19. Thirty New Low-mass Spectroscopic Binaries

    Science.gov (United States)

    Shkolnik, Evgenya L.; Hebb, Leslie; Liu, Michael C.; Reid, I. Neill; Collier Cameron, Andrew

    2010-06-01

    As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic binaries. We find a low-mass spectroscopic binary fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known low-mass spectroscopic binaries (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two low-mass eclipsing binaries (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P rot to determine the true orbital parameters. For those with no P rot, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for low-mass multiple systems. Based on observations collected at the W. M. Keck Observatory, the Canada-France-Hawaii Telescope and by the WASP Consortium. The Keck Observatory is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation. The CFHT is operated by the National Research Council of Canada

  20. Physical Structure of Four Symbiotic Binaries

    Science.gov (United States)

    Kenyon, Scott J. (Principal Investigator)

    1997-01-01

    Disk accretion powers many astronomical objects, including pre-main sequence stars, interacting binary systems, and active galactic nuclei. Unfortunately, models developed to explain the behavior of disks and their surroundings - boundary layers, jets, and winds - lack much predictive power, because the physical mechanism driving disk evolution - the viscosity - is not understood. Observations of many types of accreting systems are needed to constrain the basic physics of disks and provide input for improved models. Symbiotic stars are an attractive laboratory for studying physical phenomena associated with disk accretion. These long period binaries (P(sub orb) approx. 2-3 yr) contain an evolved red giant star, a hot companion, and an ionized nebula. The secondary star usually is a white dwarf accreting material from the wind of its red giant companion. A good example of this type of symbiotic is BF Cygni: our analysis shows that disk accretion powers the nuclear burning shell of the hot white dwarf and also manages to eject material perpendicular to the orbital plane (Mikolajewska, Kenyon, and Mikolajewski 1989). The hot components in other symbiotic binaries appear powered by tidal overflow from a very evolved red giant companion. We recently completed a study of CI Cygni and demonstrated that the accreting secondary is a solar-type main sequence star, rather than a white dwarf (Kenyon et aL 1991). This project continued our study of symbiotic binary systems. Our general plan was to combine archival ultraviolet and optical spectrophotometry with high quality optical radial velocity observations to determine the variation of line and continuum sources as functions of orbital phase. We were very successful in generating orbital solutions and phasing UV+optical spectra for five systems: AG Dra, V443 Her, RW Hya, AG Peg, and AX Per. Summaries of our main results for these systems appear below. A second goal of our project was to consider general models for the