WorldWideScience

Sample records for binary candidate slx1737-282

  1. Microlensing Binaries with Candidate Brown Dwarf Companions

    DEFF Research Database (Denmark)

    Shin, I.-G; Han, C.; Gould, A.;

    2012-01-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing ...

  2. BINARY CANDIDATES IN THE JOVIAN TROJAN AND HILDA POPULATIONS FROM NEOWISE LIGHT CURVES

    Energy Technology Data Exchange (ETDEWEB)

    Sonnett, S.; Mainzer, A.; Masiero, J.; Bauer, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T., E-mail: Sarah.Sonnett@jpl.nasa.gov [Planetary Science Institute, Tucson, AZ (United States)

    2015-02-01

    Determining the binary fraction for a population of asteroids, particularly as a function of separation between the two components, helps describe the dynamical environment at the time the binaries formed, which in turn offers constraints on the dynamical evolution of the solar system. We searched the NEOWISE archival data set for close and contact binary Trojans and Hildas via their diagnostically large light curve amplitudes. We present 48 out of 554 Hilda and 34 out of 953 Trojan binary candidates in need of follow-up to confirm their large light curve amplitudes and subsequently constrain the binary orbit and component sizes. From these candidates, we calculate a preliminary estimate of the binary fraction without confirmation or debiasing of 14%-23% for Trojans larger than ∼12 km and 30%-51% for Hildas larger than ∼4 km. Once the binary candidates have been confirmed, it should be possible to infer the underlying, debiased binary fraction through estimation of survey biases.

  3. Binary Candidates in the Jovian Trojan and Hilda Populations from NEOWISE Lightcurves

    CERN Document Server

    Sonnett, S; Grav, T; Masiero, J; Bauer, J

    2014-01-01

    Determining the binary fraction for a population of asteroids, particularly as a function of separation between the two components, helps describe the dynamical environment at the time the binaries formed, which in turn offers constraints on the dynamical evolution of the solar system. We searched the NEOWISE archival dataset for close and contact binary Trojans and Hildas via their diagnostically large lightcurve amplitudes. We present 48 out of 554 Hilda and 34 out of 953 Trojan binary candidates in need of follow-up to confirm their large lightcurve amplitudes and subsequently constrain the binary orbit and component sizes. From these candidates, we calculate a preliminary estimate of the binary fraction without confirmation or debiasing of 14-23% for Trojans larger than ~12 km and 30-51% for Hildas larger than ~4 km. Once the binary candidates have been confirmed, it should be possible to infer the underlying, debiased binary fraction through estimation of survey biases.

  4. Bright low mass eclipsing binary candidates observed by STEREO

    CERN Document Server

    Wraight, K T; White, Glenn J; Norton, A J; Bewsher, D

    2012-01-01

    Observations from the Heliospheric Imagers (HI-1) on both the STEREO spacecraft have been analysed to search for bright low mass eclipsing binaries (EBs) and potential brown dwarf transits and to determine the radii of the companions. A total of 9 EB candidates have been found, ranging in brightness from V=6.59 mag to V=11.3 mag, where the radius of the companion appears to be less than 0.4 Rsol, with a diverse range of host temperatures, from 4074 K to 6925 K. Both components of one candidate, BD-07 3648, appear to be less than 0.4 Rsol and this represents a particularly interesting system for further study. The shapes of the eclipses in some cases are not clear enough to be certain they are total and the corresponding radii found should therefore be considered as lower limits. The EBs reported in this paper have either been newly found by the present analysis, or previously reported to be eclipsing by our earlier STEREO/HI-1 results. One of the new objects has subsequently been confirmed using archival Supe...

  5. Search for Binary Black Hole Candidates from the VLBI Images of AGNs

    Indian Academy of Sciences (India)

    Xiang Liu

    2014-09-01

    We have searched the core-jet pairs in the VLBI scales (< 1 kpc), from several VLBI catalogues, and found out 5 possible Binary Black Hole (BBH) candidates. We present here the search results and analyse the candidates preliminarily. We plan to study with multi-band VLBI observation. We also plan to carry out optical line investigation in future.

  6. Review of candidates of binary systems with an RR Lyrae component

    CERN Document Server

    Skarka, Marek; Zejda, Miloslav; Mikulášek, Zdeněk

    2016-01-01

    We present an overview and current status of research on RR Lyrae stars in binary systems. In present days the number of binary candidates has steeply increased and suggested that multiple stellar systems with an RR Lyrae component is much higher than previously thought. We discuss the probability of their detection using various observing methods, compare recent results regarding selection effects, period distribution, proposed orbital parameters and the Blazhko effect.

  7. Database of candidates for RR Lyrae stars in binary systems - RRLyrBinCan

    Science.gov (United States)

    Liska, J.; Skarka, M.

    2016-05-01

    A new on-line database with RR Lyrae stars bound in binary systems is presented. Its purpose is to give a quick overview about known and suspected RR Lyrae stars in binaries on the basis of available literature. The first released version of the catalogue contains information about 61 double-star candidates, their orbital periods, method of detection, comments and active links to published papers.

  8. Surface segregation in binary alloy first wall candidate materials

    International Nuclear Information System (INIS)

    We have been studying the conditions necessary to produce a self-sustaining stable lithium monolayer on a metal substrate as a means of creating a low-Z film which sputters primarily as secondary ions. It is expected that because of the toroidal field, secondary ions originating at the first wall will be returned and contribute little to the plasma impurity influx. Aluminum and copper have, because of their high thermal conductivity and low induced radioactivity, been proposed as first wall candidate materials. The mechanical properties of the pure metals are very poorly suited to structural applications and an alloy must be used to obtain adequate hardness and tensile strength. In the case of aluminum, mechanical properties suitable for aircraft manufacture are obtained by the addition of a few at% Li. In order to investigate alloys of a similar nature as candidate structural materials for fusion machines we have prepared samples of Li-doped aluminum using both a pyro-metallurgical and a vapor-diffusion technique. The sputtering properties and surface composition have been studied as a function of sample temperature and heating time, and ion beam mass. The erosion rate and secondary ion yield of both the sputtered Al and Li have been monitored by secondary ion mass spectroscopy and Auger analysis providing information on surface segregation, depth composition profiles, and diffusion rates. The surface composition ahd lithium depth profiles are compared with previously obtained computational results based on a regular solution model of segregation, while the partial sputtering yields of Al and Li are compared with results obtained with a modified version of the TRIM computer program. (orig.)

  9. The black hole candidate binary A0620-00

    Science.gov (United States)

    Haswell, Carole Ann

    The compact object in A0620-00 was previously established as a leading black hole candidate by observations implying a minimum compact object mass, M1 approx. = 3M solar magnitude. To exclude the possibility of a neutron star primary, the constraints on M1 need to be improved. Two avenues of investigation were pursued. The mass ratio of the system, q = M1/M sub 2, was determined by observations of the radial velocity variations of the H(alpha) emission from the accretion disk around the compact object. If the wavelength shifts give an unbiased estimate of the orbital motion of the compact object, q = 10.6 + or - 2.0. However contamination by nonaxisymmetric disk emission is indicated, so q is more uncertain than the reported formal errors. The orbital inclination of the system was examined by modelling of multicolor orbital light curves, which exhibit ellipsoidal variations. The ellipsoidal amplitudes imply a spectra type of K3-K4 for the mass donor. Light curves obtained in 1986/1987 exhibit a grazing eclipse of the mass donor star by the accretion disk, providing tight constraints on the orbital inclination and the radius of the accretion disk. The accretion disk radius is comparable to the tidal radius. Limits on the orbital inclination were derived which lead to limits on the mass of the compact object: 5.50 + or - 0.15 less than or + = M1 less than or = 6.26 + or - 0.17 for q = 5.0; 4.28 + or - 0.12 less than or = M1 less than or = 4.86 + or - 0.13 for q = 10.6; 3.79 + or - 0.10 less than or = M1 less than or = 4.68 + or - 0.13 for q = 15.0. A lower limit on the mass ratio, q greater than 6.47, is established by demanding that M2 less than or = 0.85 M solar magnitude, the mass of a Roche lobe-filling main sequence star. The spectral type of the mass donor implies that q is greater than 10.6 is unlikely. Hence the results imply M1 greater than or = 4.28 + or - 0.12, which is well above the upper limit on the mass of a neutron star. This is compelling evidence

  10. Looking for Gamma-ray Emission from TeV Binary Candidates with HAWC

    CERN Document Server

    ,

    2015-01-01

    The Milky Way contains hundreds of binary systems which are known to emit in radio and X-rays, but only a handful of binaries have been observed to produce very high-energy gamma rays. In addition, the emission mechanisms which produce the gamma rays in the few known sources are not well understood. To improve the statistics of binary sources in the TeV band, the High-Altitude Water Cherenkov Gamma-ray Observatory, or HAWC, has begun to carry out a simultaneous survey of TeV binary candidates in the Northern Hemisphere between 100 GeV and 100 TeV. HAWC is a surface array that records air showers from cosmic rays and gamma rays with a high uptime and wide field of view, making it well-suited to observe time-dependent emission from objects such as TeV binaries. We describe the sensitivity of HAWC to periodic emission from Galactic sources of gamma rays and present data from the first year of observations with the partially constructed observatory.

  11. Two More Candidate AM Canum Venaticorum (AM CVn) Binaries from the Sloan Digital Sky Survey

    CERN Document Server

    Anderson, S F; Haggard, D; Prieto, J L; Knapp, G R; Sako, M; Halford, K B; Jha, S; Martin, B; Holtzman, J; Frieman, J A; Garnavich, P M; Hayward, S; Ivezic, Z; Mukadam, A S; Sesar, B; Szkody, P; Malanushenko, V; Richmond, M W; Schneider, D P; York, D G

    2008-01-01

    AM CVn systems are a select group of ultracompact binaries with the shortest orbital periods of any known binary subclass; mass-transfer is likely from a low-mass (partially-)degenerate secondary onto a white dwarf primary, driven by gravitational radiation. In the past few years, the Sloan Digital Sky Survey (SDSS) has provided five new AM CVns. Here we report on two further candidates selected from more recent SDSS data. SDSS J1208+3550 is similar to the earlier SDSS discoveries, recognized as an AM CVn via its distinctive spectrum which is dominated by helium emission. From the expanded SDSS Data Release 6 (DR6) spectroscopic area, we provide an updated surface density estimate for such AM CVns of order 10^{-3.1} to 10^{-2.5} per deg^2 for 15candidate AM CVn, SDSS J2047+0008, that was discovered in the course of followup of SDSS-II supernova candidates. It shows nova-like outbursts in multi-epoch imaging data; in contrast to the other SDSS AM CVn discoveri...

  12. Timing of eclipsing binary V0873 Per: a third body candidate

    Science.gov (United States)

    Bogomazov, A. I.; Ibrahimov, M. A.; Satovskii, B. L.; Kozyreva, V. S.; Irsmambetova, T. R.; Krushevska, V. N.; Kuznyetsova, Y. G.; Gaynullina, E. R.; Karimov, R. G.; Ehgamberdiev, S. A.; Tutukov, A. V.

    2016-01-01

    We analyze a set of moments of minima of eclipsing variable V0873 Per. V0873 Per is a short-period low-mass binary star. Data about moments of minima of V0873 Per were taken from the literature and our observations during 2013-2014. Our aim is to test the system on existence of new bodies using timing of minima of eclipses. We found a periodic variation of orbital period of V0873 Per. This variation can be explained by the gravitational influence of a third companion on the central binary star. The mass of the third body candidate is ≈ 0.2 M_{⊙}, and its orbital period is ≈300 days. The paper also includes a table with moments of minima calculated from our observations, which can be used in future investigations of V0873 Per.

  13. Fermi variability study of the candidate pulsar binary 2FGL J0523.3−2530

    OpenAIRE

    Xing, Y.; Wang, ZX; Ng, SCY

    2014-01-01

    The Fermi source 2FGL~J0523.3$-$2530 has recently been identified as a candidate millisecond pulsar binary with an orbital period of 16.5 hrs. We have carried out detailed studies of the source's emission properties by analyzing data taken with the Fermi Large Area Telescope in the 0.2--300 GeV energy range. Long-term, yearly variability from the source has been found, with a factor of 4 flux variations in 1--300 GeV. From spectral analysis, we find an extra spectral component at 2--3 GeV tha...

  14. Multi-filter Light Curves of 29 Very Short Period Candidate Contact Binaries.

    Science.gov (United States)

    Koen, C.; Koen, T.; Gray, R. O.

    2016-06-01

    Light curves of 26 probable contact binary stars are made available, from a list of candidates with the shortest periods known. This is supplemented by sets of light curves of three previously studied systems. Photometry was obtained in the Johnson UBV, Cousins RI system. All stars but one were observed in four wavebands, either UBV RC or {BV}{({RI})}C, depending on brightness. Tentative spectral classifications are given for 23 of the stars. Effective temperatures are derived from infrared and optical photometric indices, and from spectral types. These are generally in good agreement. The multicolor photometry, spectral typing, and estimated effective temperatures can be used to model these systems in detail. A preliminary study, based on Fourier coefficients of the light curves, suggests that all the systems are indeed eclipsing stars, with all but a handful probably in contact configurations.

  15. Implications for planet formation from population inference of Kepler-planet-candidates and eclipsing binaries

    Science.gov (United States)

    Shabram, Megan Iris

    The Kepler Space Science Mission has revolutionized our understanding of planetary system architectures, and the diversity of planet bulk densities. From Kepler, we now have a population of ˜4,700 planet candidates and ˜ 3000 eclipsing binaries with measured light curves, from which we can begin to characterize the distribution of stars and planets to tease out relationships between planet properties and host star properties in a robust statistical manner. The results of these investigations constrain proposed planet formation theories. This dissertation analyzes three particular sub-populations observed by Kepler that are well suited for hierarchical inference to characterize their population properties. First, we investigate the eccentricity distribution for a sample of short-period planet candidates from Kepler, where both the transit and occultation are observed for each system. This subsample lends a rare opportunity for tractable inference of its eccentricity distribution, exposing at least two populations within the eccentricity distribution and potential correlations of the eccentricity with host star metallicity and planet radius. Secondly, we investigate the mass-radius-eccentricity relation for a sample of near-resonant planet-pairs from Kepler. This study greatly improves upon previous research of constraining the mass-radius relation for small planets. Furthermore, we explore the period-eccentricity distribution of eclipsing binary stars from Kepler. We find that ˜ 72% of EBs below ˜ 11 days are very circularized, where as ˜ 87% of EBs above ˜ 11 days can take on a wide range in eccentricity values including some with significant eccentricities.

  16. Period decrease in three SuperWASP eclipsing binary candidates near the short-period limit

    CERN Document Server

    Lohr, M E; Kolb, U C; Anderson, D R; Faedi, F; West, R G

    2012-01-01

    SuperWASP light curves for 53 W UMa-type eclipsing binary (EB) candidates, identified in previous work as being close to the contact binary short-period limit, were studied for evidence of period change. The orbital periods of most of the stars were confirmed, and period decrease, significant at more than 5 sigma, was observed in three objects: 1SWASP J174310.98+432709.6 (-0.055 \\pm0.003 s/yr), 1SWASP J133105.91+121538.0 (-0.075 \\pm0.013 s/yr) and 1SWASP J234401.81-212229.1 (-0.313 \\pm0.019 s/yr). The magnitudes of the observed period changes cannot be explained by magnetic braking or gravitational radiation effects, and are most likely primarily due to unstable mass transfer from primary to secondary components, possibly accompanied by unstable mass and angular momentum loss from the systems. If these period decreases persist, the systems could merge on a relatively short timescale.

  17. Red Giants in Eclipsing Binary and Multiple-Star Systems: Modeling and Asteroseismic Analysis of 70 Candidates from Kepler Data

    CERN Document Server

    Gaulme, Patrick; Rawls, Meredith L; Jackiewicz, Jason; Mosser, Benoit; Guzik, Joyce

    2013-01-01

    Red-giant stars are an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions Kepler and CoRoT as well as recent theoretical advances. Eclipsing binaries are also fundamental astrophysical objects, and when coupled with asteroseismology, binaries would provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. The possibility of discovering pulsating red giants in eclipsing binary systems is therefore an important goal that could potentially offer very robust characterization of these systems. Hitherto, only 1 case has been discovered with Kepler. We cross-correlated the detected red-giant and eclipsing-binary catalogs from Kepler data to find candidate systems. Light-curve modeling and mean asteroseismic properties are combined to yield measurements of periods, masses, radii,...

  18. RED GIANTS IN ECLIPSING BINARY AND MULTIPLE-STAR SYSTEMS: MODELING AND ASTEROSEISMIC ANALYSIS OF 70 CANDIDATES FROM KEPLER DATA

    Energy Technology Data Exchange (ETDEWEB)

    Gaulme, P.; McKeever, J.; Rawls, M. L.; Jackiewicz, J. [Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Mosser, B. [LESIA, CNRS, Universite Pierre et Marie Curie, Universite Denis Diderot, Observatoire de Paris, F-92195 Meudon cedex (France); Guzik, J. A., E-mail: gaulme@nmsu.edu [Los Alamos National Laboratory, XTD-2, MS T-086, Los Alamos, NM 87545-2345 (United States)

    2013-04-10

    Red giant stars are proving to be an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions CoRoT and Kepler as well as recent theoretical advances. Eclipsing binaries are also fundamental astrophysical objects, and when coupled with asteroseismology, binaries provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. The possibility of discovering pulsating red giants in eclipsing binary systems is therefore an important goal that could potentially offer very robust characterization of these systems. Until recently, only one case has been discovered with Kepler. We cross-correlate the detected red giant and eclipsing-binary catalogs from Kepler data to find possible candidate systems. Light-curve modeling and mean properties measured from asteroseismology are combined to yield specific measurements of periods, masses, radii, temperatures, eclipse timing variations, core rotation rates, and red giant evolutionary state. After using three different techniques to eliminate false positives, out of the 70 systems common to the red giant and eclipsing-binary catalogs we find 13 strong candidates (12 previously unknown) to be eclipsing binaries, one to be a non-eclipsing binary with tidally induced oscillations, and 10 more to be hierarchical triple systems, all of which include a pulsating red giant. The systems span a range of orbital eccentricities, periods, and spectral types F, G, K, and M for the companion of the red giant. One case even suggests an eclipsing binary composed of two red giant stars and another of a red giant with a {delta}-Scuti star. The discovery of multiple pulsating red giants in eclipsing binaries provides an exciting test bed for precise astrophysical modeling, and follow-up spectroscopic observations of many

  19. Investigation of the binary fraction among candidate A-F type hybrid stars detected by Kepler

    Directory of Open Access Journals (Sweden)

    Lampens P.

    2015-01-01

    Full Text Available We are currently monitoring up to 40 Kepler candidate δ Scuti-γ Doradus (resp. γ Doradus-δ Scuti hybrid stars in radial velocity in order to identify the physical cause behind the low frequencies observed in the periodograms based on the ultra-high accuracy Kepler space photometry. The presence of low frequency variability in unevolved or slightly evolved oscillating A/F-type stars can generally be explained in three ways: either 1 the star is an (undetected binary or multiple system, or 2 the star is a g-mode pulsator (i.e. a genuine hybrid, or 3 the star’s atmosphere displays an asymmetric intensity distribution (caused by spots, i.e. chemical anomalies, or by (very high rotation, which is detected through rotational modulation. Our targets were selected from the globally characterized variable A/F-type stars of the Kepler mission [7]. We observe each star at least 4 times unevenly spread over a time lapse up to 2 months with the HERMES spectrograph [6]. In the case of composite, multiple-lined spectra, these observations also provide the atmospheric properties of each component. Our principal goal is to estimate the fraction of short-period, spectroscopic systems in the sample.

  20. A method to identify and characterise binary candidates - a study of CoRoT

    CERN Document Server

    Da Silva, Ronaldo

    2011-01-01

    The analysis of the CoRoT space mission data was performed aiming to test a method that selects, among the several light curves observed, the transiting systems that likely host a low-mass star orbiting the main target. The method identifies stellar companions by fitting a model to the observed transits. Applying this model, that uses equations like Kepler's third law and an empirical mass-radius relation, it is possible to estimate the mass and radius of the primary and secondary objects as well as the semimajor axis and inclination angle of the orbit. We focus on how the method can be used in the characterisation of transiting systems having a low-mass stellar companion with no need to be monitored with radial-velocity measurements or ground-based photometric observations. The model, which provides a good estimate of the system parameters, is also useful as a complementary approach to select possible planetary candidates. A list of confirmed binaries together with our estimate of their parameters are presen...

  1. Robust high-contrast companion detection from interferometric observations. The CANDID algorithm and an application to six binary Cepheids

    OpenAIRE

    Gallenne, A.; Mérand, A.; Kervella, P; Monnier, J. D.; Schaefer, G. H.; Baron, F; Breitfelder, J.; Bouquin, J. B. Le; Roettenbacher, R. M.; Gieren, W.; Pietrzynski, G.; McAlister, H.; Brummelaar, T. ten; Sturmann, J.; Sturmann, L.

    2015-01-01

    Long-baseline interferometry is an important technique to spatially resolve binary or multiple systems in close orbits. By combining several telescopes together and spectrally dispersing the light, it is possible to detect faint components around bright stars. Aims. We provide a rigorous and detailed method to search for high-contrast companions around stars, determine the detection level, and estimate the dynamic range from interferometric observations. We developed the code CANDID (Companio...

  2. A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

    CERN Document Server

    D'Orazio, Daniel J; Duffell, Paul; Farris, Brian D; MacFadyen, Andrew I

    2015-01-01

    Graham et al. (2015) have detected a 5.2 year periodic optical variability of the quasar PG 1302-102 at redshift $z=0.3$, which they interpret as the redshifted orbital period $(1+z)t_{\\rm bin}$ of a putative supermassive black hole binary (SMBHB). Here we consider the implications of a $3-8$ times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal--mass SMBHBs ($q\\equiv M_2/M_1\\gtrsim 0.3$). With the corresponding $2-4$ times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fueled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter $t_{\\rm bin}$, among bright quasars, would be reduced by 1-2 orders of magnitude, compared to the 5.2 year period, in better agreement with the rarity of candidates reported by Graham et al. (2015). Finally, shorter periods would imply higher binary speeds, possibly imprin...

  3. SDSS J0159+0105: A Radio-Quiet Quasar with a Centi-Parsec Supermassive Black Hole Binary Candidate

    CERN Document Server

    Zheng, Zhen-Ya; Shen, Yue; Jiang, Linhua; Wang, Jun-Xian; Chen, Xian; Cuadra, Jorge

    2015-01-01

    We report a candidate centi-parsec supermassive black hole binary (SMBHB) in the radio-quiet quasar SDSS J0159+0105 at z=0.217. The 8.1-year Catalina V-band light curve for this quasar reveals two significant (at P>99%) periodic signals at ~741 day and ~1500 day. The period ratio, which is close to 1:2, is typical of a black-hole binary system with a mass ratio of 0.05binary. SDSS J0159+0105 also has two SDSS spectroscopic observations separated by ~10 years. There is a significant change in the broad H-beta profile between the two epochs, which can be explained by a single broad-line region (BLR) around the binary system illuminated by the aforementioned mini-disks, or a stream of gas flowing from the c...

  4. KEPLER OBSERVATIONS OF THREE PRE-LAUNCH EXOPLANET CANDIDATES: DISCOVERY OF TWO ECLIPSING BINARIES AND A NEW EXOPLANET

    International Nuclear Information System (INIS)

    Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter 1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 RJupiter in a 3.9 day orbit.

  5. Relativistic boost as the cause of periodicity in a massive black-hole binary candidate.

    Science.gov (United States)

    D'Orazio, Daniel J; Haiman, Zoltán; Schiminovich, David

    2015-09-17

    Because most large galaxies contain a central black hole, and galaxies often merge, black-hole binaries are expected to be common in galactic nuclei. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries, most recently in PG 1302-102, which has a short rest-frame optical period of four years (ref. 6). If the orbital period of the black-hole binary matches this value, then for the range of estimated black-hole masses, the components would be separated by 0.007-0.017 parsecs, implying relativistic orbital speeds. There has been much debate over whether black-hole orbits could be smaller than one parsec (ref. 7). Here we report that the amplitude and the sinusoid-like shape of the variability of the light curve of PG 1302-102 can be fitted by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary. We predict that brightness variations in the ultraviolet light curve track those in the optical, but with a two to three times larger amplitude. This prediction is relatively insensitive to the details of the emission process, and is consistent with archival ultraviolet data. Follow-up ultraviolet and optical observations in the next few years can further test this prediction and confirm the existence of a binary black hole in the relativistic regime. PMID:26381982

  6. A Radio-Selected Black Hole X-ray Binary Candidate in the Milky Way Globular Cluster M62

    CERN Document Server

    Chomiuk, Laura; Maccarone, Thomas J; Miller-Jones, James C A; Heinke, Craig; Noyola, Eva; Seth, Anil C; Ransom, Scott

    2013-01-01

    We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we term M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl G. Jansky Very Large Array. M62-VLA1 is a faint source, with a flux density of 18.7 +/- 1.9 microJy at 6.2 GHz and a flat radio spectrum (alpha=-0.24 +/- 0.42, for S_nu = nu^alpha). M62 is the second Milky Way cluster with a candidate stellar-mass black hole; unlike the two candidate black holes previously found in the cluster M22, M62-VLA1 is associated with a Chandra X-ray source, supporting its identification as a black hole X-ray binary. Measurements of its radio and X-ray luminosity, while not simultaneous, place M62-VLA1 squarely on the well-established radio--X-ray correlation for stellar-mass black holes. In archival Hubble Space Telescope imaging, M62-VLA1 is coincident with a star near the lower red giant branch. This possible optical counterpart shows a blue exce...

  7. Multiple periods in the variability of the supermassive black hole binary candidate quasar PG1302-102?

    CERN Document Server

    Charisi, Maria; Haiman, Zoltán; Price-Whelan, Adrian M; Márka, Szabolcs

    2015-01-01

    Graham et al. (2015) discovered a supermassive black hole binary (SMBHB) candidate and identified the detected 5.2 yr period of the optical variability as the orbital period of the binary. Hydrodynamical simulations predict multiple periodic components for the variability of SMBHBs, thus raising the possibility that the true period of the binary is different from 5.2 yr. We analyse the periodogram of PG1302 and find no compelling evidence for additional peaks. We derive upper limits on any additional periodic modulations in the available data, by modeling the light-curve as the sum of red noise and the known 5.2 yr periodic component, and injecting additional sinusoidal signals. We find that, with the current data, we would be able to detect with high significance (false alarm probability <1%) secondary periodic terms with periods in the range predicted by the simulations, if the amplitude of the variability was at least ~0.07 mag (compared to 0.14 mag for the main peak). A three-year follow-up monitoring ...

  8. Ultracompact AM CVn Binaries from the Sloan Digital Sky Survey: Three Candidates Plus the First Confirmed Eclipsing System

    CERN Document Server

    Anderson, S F; Homer, L; Joshi, N R; Margon, B; Silvestri, N M; Szkody, P; Wolfe, M A; Agol, E; Becker, A C; Henden, A; Hall, P B; Knapp, G R; Richmond, M W; Schneider, D P; Stinson, G; Barentine, J C; Brewington, H J; Brinkmann, J; Harvanek, M; Kleinman, S J; Krzesínski, J; Long, D; Neilsen, E H; Nitta, A; Snedden, S A; Anderson, Scott F.; Haggard, Daryl; Homer, Lee; Joshi, Nikhil R.; Margon, Bruce; Silvestri, Nicole M.; Szkody, Paula; Wolfe, Michael A.; Agol, Eric; Becker, Andrew C.; Henden, Arne; Hall, Patrick B.; Knapp, Gillian R.; Richmond, Michael W.; Schneider, Donald P.; Stinson, Gregory; Brewington, Howard J.; Harvanek, Michael; Krzesinski, Jurek; Long, Dan; Neilsen, Eric H.; Nitta, Atsuko; Snedden, Stephanie A.

    2005-01-01

    AM CVn systems are a rare (about a dozen previously known) class of cataclysmic variables, arguably encompassing the shortest orbital periods (down to about 10 minutes) of any known binaries. Both binary components are thought to be degenerate (or partially so), likely with mass-transfer from a helium-rich donor onto a white dwarf, driven by gravitational radiation. Although rare, AM CVn systems are of high interest as possible SN Ia progenitors, and because they are predicted to be common sources of gravity waves in upcoming experiments such as LISA. We have identified four new AM CVn candidates from the Sloan Digital Sky Survey (SDSS) spectral database. All four show hallmark spectroscopic characteristics of the AM CVn class: each is devoid of hydrogen features, and instead shows a spectrum dominated by helium. All four show double-peaked emission, indicative of helium-dominated accretion disks. Limited time-series CCD photometric follow-on data have been obtained for three of the new candidates from the AR...

  9. A Population of Short-Period Variable Quasars from PTF as Supermassive Black Hole Binary Candidates

    CERN Document Server

    Charisi, M; Haiman, Z; Price-Whelan, A M; Graham, M J; Bellm, E C; Laher, R R; Marka, S

    2016-01-01

    Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circumbinary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35,383 spectroscopically confirmed quasars in the photometric database of the Palomar Transient Factory (PTF). We analysed Lomb-Scargle periodograms and assessed the significance of our findings by modeling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PT...

  10. Photometric variability of candidate white dwarf binary systems from Palomar Transient Factory archival data

    CERN Document Server

    Kao, Wil; Prince, Thomas A; Tang, Sumin; Ene, Irina; Kim, Kyu Bin; Levitan, David; Kulkarni, Shrinivas R; Laher, Russ R

    2016-01-01

    We present a sample of 59 periodic variables from the Palomar Transient Factory, selected from published catalogues of white dwarf (WD) candidates. The variability can likely be attributed to ellipsoidal variation of the tidally distorted companion induced by the gravity of the primary (WD or hot subdwarf) or to the reflection of hot emission by a cooler companion. We searched 11,311 spectroscopically or photometrically selected WD candidates from three hot star/WD catalogues, using the Lomb-Scargle periodogram to single out promising sources. We present period estimates for the candidates, 45 of which were not previously identified as periodic variables, and find that most have a period shorter than a few days. Additionally, we discuss the eclipsing systems in our sample and present spectroscopic data on selected sources.

  11. Photometric variability of candidate white dwarf binary systems from Palomar Transient Factory archival data

    Science.gov (United States)

    Kao, Wil; Kaplan, David L.; Prince, Thomas A.; Tang, Sumin; Ene, Irina; Kim, Kyu Bin; Levitan, David; Kulkarni, Shrinivas R.; Laher, Russ R.

    2016-09-01

    We present a sample of 59 periodic variables from the Palomar Transient Factory, selected from published catalogues of white dwarf (WD) candidates. The variability can likely be attributed to ellipsoidal variation of the tidally distorted companion induced by the gravity of the primary (WD or hot subdwarf) or to the reflection of hot emission by a cooler companion. We searched 11 311 spectroscopically or photometrically selected WD candidates from three hot star/WD catalogues, using the Lomb-Scargle periodogram to single out promising sources. We present period estimates for the candidates, 45 of which were not previously identified as periodic variables, and find that most have a period shorter than a few days. Additionally, we discuss the eclipsing systems in our sample and present spectroscopic data on selected sources.

  12. Unveiling the radio counterparts of two binary AGN candidates: J1108+0659 and J1131-0204

    Science.gov (United States)

    Bondi, M.; Pérez-Torres, M. A.; Piconcelli, E.; Fu, H.

    2016-04-01

    The sources SDSS J113126.08-020459.2 and SDSS J110851.04+065901.4 are two double-peaked [O III] emitting active galactic nuclei (AGNs), identified as candidate binary AGNs by optical and near infrared (NIR) observations. We observed the two sources with high resolution Very Long Baseline Interferometry (VLBI) using the European VLBI Network at 5 GHz, reduced VLA observations at three frequencies available for one of the sources, and used archival HST observations. For the source SDSS J113126.08-020459.2, the VLBI observations detected only one single compact component associated with the eastern NIR nucleus. In SDSS J110851.04+065901.4, the VLBI observations did not detect any compact components, but the VLA observations allowed us to identify a possible compact core in the region of the north-western optical/NIR nucleus. In this source we find kpc-scale extended radio emission that is spatially coincident to the ultraviolet continuum and to the extended emission narrow line region. The UV continuum is significantly obscured since the amount of extended radio emission yields a star formation rate of about 110 M⊙ yr-1, which is an order of magnitude larger than implied by the observed ultraviolet emission. Our analysis confirms the presence of only one AGN in the two candidate binary AGNs. FITS files of the reduced images are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A102

  13. A census of AM CVn stars: three new candidates and one confirmed 48.3-minute binary

    CERN Document Server

    Rau, Arne; Groot, Paul J; Marsh, Tom R; Nelemans, Gijs; Steeghs, Danny; Kasliwal, Mansi M

    2009-01-01

    We present three new candidate AM CVn binaries, plus one confirmed new system, from a spectroscopic survey of color-selected objects from the Sloan Digital Sky Survey. All four systems were found from their helium emission lines in low-resolution spectra taken on the Hale telescope at Palomar, and the Nordic Optical Telescope and the William Herschel Telescope on La Palma. The ultra-compact binary nature of SDSS J090221.35+381941.9 was confirmed using phase-resolved spectroscopy at the Keck-I telescope. From the characteristic radial velocity `S-wave' observed in the helium emission lines we measure an orbital period of 48.31 +/- 0.08 min. The continuum emission can be described with a blackbody or a helium white dwarf atmosphere of T_eff ~ 15,000K, in agreement with theoretical cooling models for relatively massive accretors and/or donors. The absence in the spectrum of broad helium absorption lines from the accreting white dwarf suggests that the accreting white dwarf cannot be much hotter than 15,000K, or ...

  14. A candidate supermassive binary black hole system in the brightest cluster galaxy of RBS 797

    CERN Document Server

    Gitti, M; Giovannini, G; Feretti, L; Liuzzo, E

    2013-01-01

    The radio source at the center of the cool core galaxy cluster RBS 797 (z=0.35) is known to exhibit a misalignment of its radio jets and lobes observed at different VLA-scale, with the innermost kpc-scale jets being almost orthogonal to the radio emission which extends for tens of kpc filling the X-ray cavities. Gitti et al. suggested that this peculiar radio morphology may indicate a recurrent activity of the central radio source, where the jet orientation is changing between the different outbursts due to the effects of supermassive binary black holes (SMBBHs). We aim at unveiling the nuclear radio properties of the brightest cluster galaxy (BCG) in RBS 797 and at investigating the presence of a SMBBH system in its center. We have performed new high-resolution observations at 5 GHz with the European VLBI Network (EVN), reaching an angular resolution of 9x5 mas^2 and a sensitivity of 36 microJy/beam. We report the EVN detection of two compact components in the BCG of RBS 797, with a projected separation of ~...

  15. New massive X-ray binary candidates from the ROSAT Galactic Plane Survey I - Results from a cross-correlation with OB star catalogues

    OpenAIRE

    Motch, C.; Haberl, F.; Dennerl, K.; Pakull, M.; Janot-Pacheco, E.

    1996-01-01

    We report the discovery of several new OB/X-ray accreting binary candidates. These massive systems were found by cross-correlating in position SIMBAD OB star catalogues with the part of the ROSAT all-sky survey located at low galactic latitudes (|b| 10^31 erg/s. Fol...

  16. A CAUTIONARY TALE: MARVELS BROWN DWARF CANDIDATE REVEALS ITSELF TO BE A VERY LONG PERIOD, HIGHLY ECCENTRIC SPECTROSCOPIC STELLAR BINARY

    International Nuclear Information System (INIS)

    We report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV) measurements (R ∼Jup) to a solar-type primary. At least three properties of this system allow it to masquerade as a single star with a very-low-mass companion: its large eccentricity (e ∼ 0.8), its relatively long period (P ∼ 238 days), and the approximately perpendicular orientation of the semi-major axis with respect to the line of sight (ω ∼ 189°). As a result of these properties, for ∼95% of the orbit the two sets of stellar spectral lines are completely blended, and the RV measurements based on centroiding on the apparently single-lined spectrum is very well fit by an orbit solution indicative of a brown dwarf companion on a more circular orbit (e ∼ 0.3). Only during the ∼5% of the orbit near periastron passage does the true, double-lined nature and large RV amplitude of ∼15 km s–1 reveal itself. The discovery of this binary system is an important lesson for RV surveys searching for substellar companions; at a given resolution and observing cadence, a survey will be susceptible to these kinds of astrophysical false positives for a range of orbital parameters. Finally, for surveys like MARVELS that lack the resolution for a useful line bisector analysis, it is imperative to monitor the peak of the cross-correlation function for suspicious changes in width or shape, so that such false positives can be flagged during the candidate vetting process.

  17. Discovery and identification of infrared counterpart candidates of four Galactic centre low mass X-ray binaries

    CERN Document Server

    Curran, P A; Heras, J A Zurita

    2011-01-01

    The near infrared (nIR)/optical counterparts of low mass X-ray binaries (LMXBs) are often observationally dim and reside in high source density fields which make their identification problematic; however, without such a counterpart identification we are unable to investigate many of the properties of LMXB systems. Here, in the context of a larger identification campaign, we examine the fields of four LMXB systems near the Galactic centre, in a bid to identify nIR/optical counterparts to the previously detected X-ray point sources. We obtain nIR/optical images of the fields with the ESO - New Technology Telescope and apply standard photometric and astrometric calibrations; these data are supplemented by Spitzer-GLIMPSE catalog data. On the basis of positional coincidence with the arcsecond accurate X-ray positions, we identify unambiguous counterpart candidates for XTE J1637-498, IGR J17379-3747, IGR J17585-3057 and GX 9+1. We propose tentative nIR counterparts of four LMXBs which require further investigation...

  18. High-energy electromagnetic offline follow-up of LIGO-Virgo gravitational-wave binary coalescence candidate events

    CERN Document Server

    Blackburn, Lindy; Camp, Jordan; Christensen, Nelson; Connaughton, Valerie; Jenke, Peter; Remillard, Ronald A; Veitch, John

    2014-01-01

    We present two different search methods for electromagnetic counterparts to gravitational-wave events from ground-based detectors using archival NASA high-energy data from the Fermi-GBM and RXTE-ASM instruments. To demonstrate the methods, we use a limited number of representative gravitational-wave background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either EM instrument coincident with a GW event we are able to reject a large majority of GW candidates, which reduces the signal-to-noise of the...

  19. High-Energy Electromagnetic Offline Follow-Up of Ligo-Virgo Gravitational-Wave Binary Coalescence Candidate Events

    Science.gov (United States)

    Blackburn, L.; Briggs, M. S.; Camp, J.; Christensen, N.; Connaughton, V.; Jenke, P.; Remillard, R. A.; Veitch, J.

    2015-01-01

    We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15-20 percent.

  20. The accretion-ejection coupling in the black hole candidate X-ray binary MAXI J1836-194

    CERN Document Server

    Russell, T D; Miller-Jones, J C A; Curran, P A; Markoff, S; Russell, D M; Sivakoff, G R

    2013-01-01

    We present the results of our quasi-simultaneous radio, sub-mm, infrared, optical and X-ray study of the Galactic black hole candidate X-ray binary MAXI J1836-194 during its 2011 outburst. We consider the full multi-wavelength spectral evolution of the outburst, investigating whether the evolution of the jet spectral break (the transition between optically-thick and optically-thin synchrotron emission) is caused by any specific properties of the accretion flow. Our observations show that the break does not scale with the X-ray luminosity or with the inner radius of the accretion disk, and is instead likely to be set by much more complex processes. We find that the radius of the acceleration zone at the base of the jet decreases from ~10$^6$ gravitational radii during the hard intermediate state to ~10$^3$ gravitational radii as the outburst fades (assuming a black hole mass of 8 M$_{\\odot}$), demonstrating that the electrons are accelerated on much larger scales than the radius of the inner accretion disk and...

  1. Unveiling the radio counterparts of two binary AGN candidates: J1108+0659 and J1131-0204

    CERN Document Server

    Bondi, M; Piconcelli, E; Fu, H

    2016-01-01

    The sources SDSS\\,J113126.08-020459.2 and SDSS\\,J110851.04+065901.4 are two double-peaked [O III] emitting AGN, identified as candidate binary AGNs by optical and near infrared (NIR) observations. We observed the two sources with high resolution Very Long Baseline Interferometry (VLBI) using the European VLBI Network at 5\\,GHz, reduced VLA observations at three frequencies available for one of the sources, and used archival HST observations. For the source SDSS\\,J113126.08-020459.2, the VLBI observations detected only one single compact component associated with the eastern NIR nucleus. In SDSS\\,J110851.04+065901.4, the VLBI observations did not detect any compact components, but the VLA observations allowed us to identify a possible compact core in the region of the north-western optical/NIR nucleus. In this source we find kpc-scale extended radio emission that is spatially coincident to the ultraviolet continuum and to the extended emission narrow line region. The UV continuum is significantly obscured sinc...

  2. Planet Hunters. X. Searching for Nearby Neighbors of 75 Planet and Eclipsing Binary Candidates from the K2 Kepler extended mission

    Science.gov (United States)

    Schmitt, Joseph R.; Tokovinin, Andrei; Wang, Ji; Fischer, Debra A.; Kristiansen, Martti H.; LaCourse, Daryll M.; Gagliano, Robert; Tan, Arvin Joseff V.; Schwengeler, Hans Martin; Omohundro, Mark R.; Venner, Alexander; Terentev, Ivan; Schmitt, Allan R.; Jacobs, Thomas L.; Winarski, Troy; Sejpka, Johann; Jek, Kian J.; Boyajian, Tabetha S.; Brewer, John M.; Ishikawa, Sascha T.; Lintott, Chris; Lynn, Stuart; Schawinski, Kevin; Schwamb, Megan E.; Weiksnar, Alex

    2016-06-01

    We present high-resolution observations of a sample of 75 K2 targets from Campaigns 1–3 using speckle interferometry on the Southern Astrophysical Research (SOAR) telescope and adaptive optics imaging at the Keck II telescope. The median SOAR I-band and Keck Ks-band detection limits at 1\\prime\\prime were {{Δ }}{m}I=4.4 mag and {{Δ }}{m}{Ks}=6.1 mag, respectively. This sample includes 37 stars likely to host planets, 32 targets likely to be eclipsing binaries (EBs), and 6 other targets previously labeled as likely planetary false positives. We find nine likely physically bound companion stars within 3\\prime\\prime of three candidate transiting exoplanet host stars and six likely EBs. Six of the nine detected companions are new discoveries. One of these new discoveries, EPIC 206061524, is associated with a planet candidate. Among the EB candidates, companions were only found near the shortest period ones (P\\lt 3 days), which is in line with previous results showing high multiplicity near short-period binary stars. This high-resolution data, including both the detected companions and the limits on potential unseen companions, will be useful in future planet vetting and stellar multiplicity rate studies for planets and binaries.

  3. Finding binary active galactic nuclei candidates by the centroid shift in imaging surveys II. Testing the method with SDSS J233635.75-010733.7

    CERN Document Server

    Liu, Yuan

    2016-01-01

    In Liu (2015), we propose selecting binary active galactic nuclei (AGNs) candidates using the centroid shift of the images, which is induced by the non-synchronous variations of the two nuclei. In this paper, a known binary AGN (SDSS J233635.75-010733.7) is employed to verify the ability of this method. Using 162 exposures in the $R$ band of \\textit{Palomar Transient Factory} (PTF), an excess of dispersion in the positional distribution of the binary AGN is detected, though the two nuclei cannot be resolved in the images of PTF. We also propose a new method to compare the position of the binary AGN in PTF $g$ and $R$ band and find the difference is highly significant even only with 20 exposures. This new method is efficient for two nuclei with different spectral energy distributions, e.g., type I + type II AGN or off-set AGN. Large-scale surveys, e.g., the Panoramic Survey Telescope and Rapid Response System and the Large Synoptic Survey Telescope, are expected to discover a large sample of binary AGN candida...

  4. Investigation of a transiting planet candidate in Trumpler 37: An astrophysical false positive eclipsing spectroscopic binary star

    Science.gov (United States)

    Errmann, R.; Torres, G.; Schmidt, T. O. B.; Seeliger, M.; Howard, A. W.; Maciejewski, G.; Neuhäuser, R.; Meibom, S.; Kellerer, A.; Dimitrov, D. P.; Dincel, B.; Marka, C.; Mugrauer, M.; Ginski, Ch.; Adam, Ch.; Raetz, St.; Schmidt, J. G.; Hohle, M. M.; Berndt, A.; Kitze, M.; Trepl, L.; Moualla, M.; Eisenbeiß, T.; Fiedler, S.; Dathe, A.; Graefe, Ch.; Pawellek, N.; Schreyer, K.; Kjurkchieva, D. P.; Radeva, V. S.; Yotov, V.; Chen, W. P.; Hu, S. C.-L.; Wu, Z.-Y.; Zhou, X.; Pribulla, T.; Budaj, J.; Vaňko, M.; Kundra, E.; Hambálek, Ľ.; Krushevska, V.; Bukowiecki, Ł.; Nowak, G.; Marschall, L.; Terada, H.; Tomono, D.; Fernandez, M.; Sota, A.; Takahashi, H.; Oasa, Y.; Briceño, C.; Chini, R.; Broeg, C. H.

    We report our investigation of the first transiting planet candidate from the YETI project in the young (˜4 Myr old) open cluster Trumpler 37. The transit-like signal detected in the lightcurve of F8V star 2M21385603+5711345 repeats every 1.364894±0.000015 days, and has a depth of 54.5±0.8 mmag in R. Membership in the cluster is supported by its mean radial velocity and location in the color-magnitude diagram, while the Li diagnostic and proper motion are inconclusive in this regard. Follow-up photometric monitoring and adaptive optics imaging allow us to rule out many possible blend scenarios, but our radial-velocity measurements show it to be an eclipsing single-lined spectroscopic binary with a late-type (mid-M) stellar companion, rather than one of planetary nature. The estimated mass of the companion is 0.15-0.44 M⊙. The search for planets around very young stars such as those targeted by the YETI survey remains of critical importance to understand the early stages of planet formation and evolution. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration (Proposal ID H215Hr). The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC, Proposal IDs H10-3.5-015 and H10-2.2-004). Some of the observations reported here were obtained at

  5. Vetting Kepler Planet Candidates with Multi-Color Photometry from the GTC: Identification of an Eclipsing Binary Star Near KOI 565

    CERN Document Server

    Colon, Knicole D

    2011-01-01

    We report the discovery of an eclipsing binary star (KIC 7025851) near KOI 565 (KIC 7025846) based on photometric observations of KOI 565 and several nearby stars acquired in two narrow bandpasses (790.2 and 794.3\\pm2.0 nm) nearly-simultaneously with the GTC/OSIRIS. We use the individual photometry in each bandpass as well as the colors of KOI 565 and other nearby stars to determine that the source of the transit signal initially detected by Kepler is not due to a super-Earth-size planet around KOI 565. Instead, we find the source to be a background eclipsing binary star located \\sim15 arcsec to the North of KOI 565. We discuss future prospects for using high-precision multi-color photometry from the GTC to determine whether additional Kepler planet candidates have a planetary nature or are instead false positives (e.g., foreground or background eclipsing binaries or hierarchical triple systems). Our approach is complementary to multi-color follow-up observations of Kepler planet candidates currently being co...

  6. Planet Hunters X: Searching for Nearby Neighbors of 75 Planet and Eclipsing Binary Candidates from the K2 Kepler extended mission

    CERN Document Server

    Schmitt, Joseph R; Wang, Ji; Fischer, Debra A; Kristiansen, Martti H; LaCourse, Daryll M; Gagliano, Robert; Tan, Arvin Joseff V; Schwengeler, Hans Martin; Omohundro, Mark R; Venner, Alexander; Terentev, Ivan; Schmitt, Allan R; Jacobs, Thomas L; Winarski, Troy; Sejpka, Johann; Jek, Kian J; Boyajian, Tabetha S; Brewer, John M; Ishikawa, Sascha T; Lintott, Chris; Lynn, Stuart; Schawinski, Kevin; Weiksnar, Alex

    2016-01-01

    We present high resolution observations of a sample of 75 K2 targets from Campaigns 1-3 using speckle interferometry on the Southern Astrophysical Research (SOAR) telescope and adaptive optics (AO) imaging at the Keck II telescope. The median SOAR $I$-band and Keck $K_s$-band detection limits at 1'' were $\\Delta m_{I}=4.4$ mag and $\\Delta m_{K_s}=6.1$ mag, respectively. This sample includes 37 stars likely to host planets, 32 targets likely to be EBs, and 6 other targets previously labeled as likely planetary false positives. We find nine likely physically bound companion stars within 3'' of three candidate transiting exoplanet host stars and six likely eclipsing binaries (EB). Six of the nine detected companions are new discoveries, one of them associated with a planet candidate (EPIC 206061524). Among the EB candidates, companions were only found near the shortest period ones ($P<3$ days), which is in line with previous results showing high multiplicity near short-period binary stars. This high resolutio...

  7. A Cautionary Tale: MARVELS Brown Dwarf Candidate Reveals Itself To Be A Very Long Period, Highly Eccentric Spectroscopic Stellar Binary

    CERN Document Server

    Mack, Claude E; Deshpande, Rohit; Wisniewski, John P; Stassun, Keivan G; Gaudi, B Scott; Fleming, Scott W; Mahadevan, Suvrath; De Lee, Nathan; Eastman, Jason; Ghezzi, Luan; Hernandez, Jonay I Gonzalez; Femenia, Bruno; Ferreira, Leticia; de Mello, Gustavo Porto; Crepp, Justin R; Sanchez, Daniel Mata; Agol, Eric; Beatty, Thomas G; Bizyaev, Dmitry; Brewington, Howard; Cargile, Phillip A; da Costa, Luiz N; Esposito, Massimiliano; Ebelke, Garret; Hebb, Leslie; Jiang, Peng; Kane, Stephen R; Lee, Brian; Maia, Marcio A G; Malanushenko, Elena; Malanushenko, Victor; Oravetz, Daniel; Paegert, Martin; Pan, Kaike; Prieto, Carlos Allende; Peper, Joshua; Rebolo, Rafael; Roy, Arpita; Santiago, Basilio X; Schneider, Donald P; Simmons, Audrey; Siverd, Robert J; Snedden, Stephanie; Tofflemire, Benjamin M

    2013-01-01

    We report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV) measurements (R ~ <30,000), this particular stellar binary mimics a single-lined binary with an RV signal that would be induced by a brown dwarf companion (Msin(i)~50 M_Jup) to a solar-type primary. At least three properties of this system allow it to masquerade as a single star with a very low-mass companion: its large eccentricity (e~0.8), its relatively long period (P~238 days), and the approximately perpendicular orientation of the semi-major axis with respect to the line of sight (omega~189 degrees). As a result of these properties, for ~95% of the orbit the two sets of stellar spectral lines are completely blended, and the RV measurements based on centroiding ...

  8. IRAS 16253-2429: the First Proto-Brown Dwarf Binary Candidate Identified through Dynamics of Jets

    CERN Document Server

    Hsieh, Tien-Hao; Belloche, Arnaud; Wyrowski, Friedrich

    2016-01-01

    The formation mechanism of brown dwarfs (BDs) is one of the long-standing problems in star formation because the typical Jeans mass in molecular clouds is too large to form these substellar objects. To answer this question, it is crucial to study a BD at the embedded phase. IRAS 16253-2429 is classified as a very low luminosity object (VeLLO) with internal luminosity 0.1 Lsun. VeLLOs are believed to be very low-mass protostars or even proto-BDs. We observed the jet/outflow driven by IRAS 16253-2429 in CO (2-1), (6-5), and (7-6) using the IRAM 30 m and APEX telescopes and the SMA in order to study its dynamical features and physical properties. Our SMA map reveals two protostellar jets, indicating the existence of a proto-binary system as implied by the precessing jet detected in H2 emission. We detect a wiggling pattern in the position-velocity diagrams along the jet axes, which is likely due to the binary orbital motion. Based on this, we derive the current mass of the binary as ~0.032 Msun. Given the low en...

  9. New insights on the recoiling/binary black hole candidate J0927+2943 via molecular gas observations

    OpenAIRE

    Decarli, Roberto; Dotti, Massimo; Mazzucchelli, Chiara; Montuori, Carmen; Volonteri, Marta

    2014-01-01

    The peculiar QSO J0927+2943 shows multiple sets of emission lines in its optical spectrum. This signature has been interpreted as the relative motion between a black hole, either recoiling or bound in a binary system, and its host galaxy, or as a superposition of two galaxies along the line of sight. In order to test these scenarios, we have collected 2mm CO(2-1) observations using the IRAM Plateau de Bure Interferometer, and optical images and spectroscopy at the Calar Alto observatory. Toge...

  10. New Radial Velocities for 30 Candidate Runaway Stars and a Possible Binary Supernova Origin for HIP 9470 and PSR J0152-1637

    CERN Document Server

    Tetzlaff, N; Bieryla, A; Neuhäuser, R

    2014-01-01

    We report new radial velocity measurements for 30 candidate runaway stars. We revise their age estimates and compute their past trajectories in the Galaxy in order to determine their birthplaces. We find that seven of the stars could be younger than ~100 Myr, and for five of them we identify multiple young clusters and associations in which they may have formed. For the youngest star in the sample, HIP 9470, we suggest a possible ejection scenario in a supernova event, and also that it may be associated with the young pulsar PSR J0152-1637. Our spectroscopic observations reveal seven of the stars in the sample of 30 to be previously unknown spectroscopic binaries. Orbital solutions for four of them are reported here as well.

  11. First Long-term Optical Spectral Monitoring of a Binary Black Hole Candidate E1821+643. I. Variability of Spectral Lines and Continuum

    Science.gov (United States)

    Shapovalova, A. I.; Popović, L. Č.; Chavushyan, V. H.; Burenkov, A. N.; Ilić, D.; Kollatschny, W.; Kovačević, A.; Valdés, J. R.; Patiño-Álvarez, V.; León-Tavares, J.; Torrealba, J.; Zhdanova, V. E.

    2016-02-01

    We report the results of the first long-term (1990-2014) optical spectrophotometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift, high-luminosity, radio-quiet quasar. In the monitored period, the continua and Hγ fluxes changed about two times, while the Hβ flux changed about 1.4 times. We found periodical variations in the photometric flux with periods of 1200, 1850, and 4000 days, and 4500-day periodicity in the spectroscopic variations. However, the periodicity of 4000-4500 days covers only one cycle of variation and should be confirmed with a longer monitoring campaign. There is an indication of the period around 1300 days in the spectroscopic light curves, buts with small significance level, while the 1850-day period could not be clearly identified in the spectroscopic light curves. The line profiles have not significantly changed, showing an important red asymmetry and broad line peak redshifted around +1000 km s-1. However, Hβ shows a broader mean profile and has a larger time lag (τ ˜ 120 days) than Hγ (τ ˜ 60 days). We estimate that the mass of the black hole is ˜2.6 × 109 M⊙. The obtained results are discussed in the frame of the binary black hole hypothesis. To explain the periodicity in the flux variability and high redshift of the broad lines, we discuss a scenario where dense, gas-rich, cloudy-like structures are orbiting around a recoiling black hole.

  12. Time-resolved X-Shooter spectra and RXTE light curves of the ultra-compact X-ray binary candidate 4U 0614+091

    CERN Document Server

    Madej, O K; Groot, P J; van Haaften, L M; Nelemans, G; Maccarone, T J

    2012-01-01

    In this paper we present X-Shooter time resolved spectroscopy and RXTE PCA light curves of the ultra-compact X-ray binary candidate 4U 0614+091. The X-Shooter data are compared to the GMOS data analyzed previously by Nelemans et al. (2004). We confirm the presence of C III and O II emission features at ~ 4650 {\\AA} and ~ 5000 {\\AA}. The emission lines do not show evident Doppler shifts that could be attributed to the motion of the donor star/hot spot around the center of mass of the binary. We note a weak periodic signal in the red-wing/blue-wing flux ratio of the emission feature at ~ 4650 {\\AA}. The signal occurs at P = 30.23 +/- 0.03 min in the X-Shooter and at P = 30.468 +/- 0.006 min in the GMOS spectra when the source was in the low/hard state. Due to aliasing effects the period in the GMOS and X-Shooter data could well be the same. We deem it likely that the orbital period is thus close to 30 min, however, as several photometric periods have been reported for this source in the literature already, furt...

  13. 1RXS J180408.9-342058: An ultra compact X-ray binary candidate with a transient jet

    Science.gov (United States)

    Baglio, M. C.; D'Avanzo, P.; Campana, S.; Goldoni, P.; Masetti, N.; Muñoz-Darias, T.; Patiño-Álvarez, V.; Chavushyan, V.

    2016-03-01

    Aims: We present a detailed near-infrared/optical/UV study of the transient low-mass X-ray binary 1RXS J180408.9-342058 performed during its 2015 outburst, which is aimed at determining the nature of its companion star. Methods: We obtained three optical spectra (R ~ 1000) at the 2.1 m San Pedro Mártir Observatory telescope (México). We performed optical and NIR photometric observations with both the REM telescope and the New Technology Telescope (NTT) in La Silla. We obtained optical and UV observations from the Swift archive. Finally, we performed optical polarimetry of the source using the EFOSC2 instrument mounted on the NTT. Results: The optical spectrum of the source is almost featureless since the hydrogen and He I emissions lines, typically observed in LMXBs, are not detected. Similarly, carbon and oxygen lines are not observed either. We marginally detect the He II 4686 Å emission line, suggesting the presence of helium in the accretion disc. No significant optical polarisation level was observed. Conclusions: The lack of hydrogen and He I emission lines in the spectrum implies that the companion is likely not a main-sequence star. Driven by the tentative detection of the He II 4686 Å emission line, we suggest that the system could harbour a helium white dwarf. If this is the case, 1RXS J180408.9-342058 would be an ultra-compact X-ray binary. By combining an estimate of the mass accretion rate together with evolutionary tracks for a He white dwarf, we obtain a tentative orbital period of ~40 min. We also built the NIR-optical-UV spectral energy distribution (SED) of the source at two different epochs. One SED was gathered when the source was in the soft X-ray state and this SED is consistent with the presence of a single thermal component. The second SED, obtained when the source was in the hard X-ray state, shows a thermal component along with a tail in the NIR, which likely indicates the presence of a (transient) jet. Based on observations made with

  14. 1RXS J180408.9-342058: an ultra compact X-ray binary candidate with a transient jet

    CERN Document Server

    Baglio, M C; Campana, S; Goldoni, P; Masetti, N; Munoz-Darias, T; Patino-Alvarez, V; Chavushyan, V

    2016-01-01

    We present a detailed NIR/optical/UV study of the transient low mass X-ray binary 1RXS J180408.9-342058 performed during its 2015 outburst, aimed at determining the nature of its companion star. We obtained three optical spectra at the 2.1 m San Pedro Martir Observatory telescope (Mexico). We performed optical and NIR photometric observations with both the REM telescope and the New Technology Telescope (NTT) in La Silla. We obtained optical and UV observations from the Swift archive. Finally, we performed optical polarimetry of the source by using the EFOSC2 instrument mounted on the NTT. The optical spectrum of the source is almost featureless since the hydrogen and He I emissions lines, typically observed in LMXBs, are not detected. Similarly, carbon and oxygen lines are neither observed. We marginally detect the He II 4686 AA emission line, suggesting the presence of helium in the accretion disc. No significant optical polarisation level was observed. The lack of hydrogen and He I emission lines in the spe...

  15. Broad-band monitoring tracing the evolution of the jet and disc in the black hole candidate X-ray binary MAXI J1659-152

    Science.gov (United States)

    van der Horst, A. J.; Curran, P. A.; Miller-Jones, J. C. A.; Linford, J. D.; Gorosabel, J.; Russell, D. M.; de Ugarte Postigo, A.; Lundgren, A. A.; Taylor, G. B.; Maitra, D.; Guziy, S.; Belloni, T. M.; Kouveliotou, C.; Jonker, P. G.; Kamble, A.; Paragi, Z.; Homan, J.; Kuulkers, E.; Granot, J.; Altamirano, D.; Buxton, M. M.; Castro-Tirado, A.; Fender, R. P.; Garrett, M. A.; Gehrels, N.; Hartmann, D. H.; Kennea, J. A.; Krimm, H. A.; Mangano, V.; Ramirez-Ruiz, E.; Romano, P.; Wijers, R. A. M. J.; Wijnands, R.; Yang, Y. J.

    2013-12-01

    MAXI J1659-152 was discovered on 2010 September 25 as a new X-ray transient, initially identified as a gamma-ray burst, but was later shown to be a new X-ray binary with a black hole as the most likely compact object. Dips in the X-ray light curves have revealed that MAXI J1659-152 is the shortest period black hole candidate identified to date. Here we present the results of a large observing campaign at radio, submillimetre, near-infrared (nIR), optical and ultraviolet (UV) wavelengths. We have combined this very rich data set with the available X-ray observations to compile a broad-band picture of the evolution of this outburst. We have performed broad-band spectral modelling, demonstrating the presence of a spectral break at radio frequencies and a relationship between the radio spectrum and X-ray states. Also, we have determined physical parameters of the accretion disc and put them into context with respect to the other parameters of the binary system. Finally, we have investigated the radio-X-ray and nIR/optical/UV-X-ray correlations up to ˜3 yr after the outburst onset to examine the link between the jet and the accretion disc, and found that there is no significant jet contribution to the nIR emission when the source is in the soft or intermediate X-ray spectral state, consistent with our detection of the jet break at radio frequencies during these states.

  16. A NuSTAR Observation of the Gamma-Ray-Emitting X-ray Binary and Transitional Millisecond Pulsar Candidate 1RXS J154439.4-112820

    CERN Document Server

    Bogdanov, Slavko

    2015-01-01

    I present a 40 kilosecond Nuclear Spectroscopic Telescope Array (NuSTAR) observation of the recently identified low-luminosity X-ray binary and transitional millisecond pulsar (tMSP) candidate 1RXS J154439.4-112820, which is associated with the high-energy gamma-ray source 3FGL J1544.6--1125. The system is detected up to ~30 keV with an extension of the same power-law spectrum and rapid large-amplitude variability between two flux levels observed in soft X-rays. These findings provide further evidence that 1RXS J154439.4-112820 belongs to the same class of objects as the nearby bona fide tMSPs PSR J1023+0038 and XSS J12270-4859 and therefore almost certainly hosts a millisecond pulsar accreting at low luminosities. I also examine the long-term accretion history of 1RXS J154439.4-112820 based on archival optical, ultraviolet, X-ray, and $\\gamma$-ray light curves covering the past $\\sim$decade. Throughout this period, the source has maintained similar flux levels at all wavelengths, which is an indication that ...

  17. A NuSTAR Observation of the Gamma-ray-emitting X-ray Binary and Transitional Millisecond Pulsar Candidate 1RXS J154439.4–112820

    Science.gov (United States)

    Bogdanov, Slavko

    2016-07-01

    I present a 40 ks Nuclear Spectroscopic Telescope Array observation of the recently identified low-luminosity X-ray binary and transitional millisecond pulsar (tMSP) candidate 1RXS J154439.4‑112820, which is associated with the high-energy γ-ray source 3FGL J1544.6‑1125. The system is detected up to ∼30 keV with an extension of the same power-law spectrum and rapid large-amplitude variability between two flux levels observed in soft X-rays. These findings provide further evidence that 1RXS J154439.4‑112820 belongs to the same class of objects as the nearby bona fide tMSPs PSR J1023+0038 and XSS J12270‑4859 and therefore almost certainly hosts a millisecond pulsar accreting at low luminosity. I also examine the long-term accretion history of 1RXS J154439.4‑112820 based on archival optical, ultraviolet, X-ray, and γ-ray light curves covering approximately the past decade. Throughout this period, the source has maintained similar flux levels at all wavelengths, which is an indication that it has not experienced prolonged episodes of a non-accreting radio pulsar state but may spontaneously undergo such events in the future.

  18. Direct Imaging and Spectroscopy of a Candidate Companion Below/Near the Deuterium-Burning Limit In The Young Binary Star System, ROXs 42B

    CERN Document Server

    Currie, Thayne; Debes, John; Lafreniere, David; Itoh, Yoichi; Jayawardhana, Ray; Ratzka, Thorsten; Correia, Sergio

    2013-01-01

    We present near-infrared high-contrast imaging photometry and integral field spectroscopy of ROXs 42B, a binary M0 star member of the 1--3 Myr-old $\\rho$ Ophiuchus star-forming region from data collected over a 7 year span. Each data set reveals a faint companion (hereafter ROXs 42Bb) located $\\sim$ 1.16" ($r_{proj}$ $\\approx$ 150 $AU$) from the primaries. ROXs 42Bb's astrometry is inconsistent with a background star but consistent with a bound companion, possibly one with detected orbital motion. The most recent data set reveals a second candidate companion at $\\sim$ 0.5" of roughly equal brightness. ROXs 42Bb's $H$ and $K_{s}$ band photometry is similar to dusty/cloudy young late M/early L dwarfs with masses at or below the deuterium-burning limit. $K$-band VLT/SINFONI spectroscopy shows ROXs 42Bb to be a cool substellar object (M8--L0; $T_{eff}$ $\\approx$ 1800--2600 $K$), not a background dwarf star, with a spectral shape indicative of young, low surface gravity companions with masses at/below the deuteriu...

  19. First long-term optical spectro-photometric monitoring of a binary black hole candidate E1821+643: I. Variability of spectral lines and continuum

    CERN Document Server

    Shapovalova, A I; Chavushyan, V H; Burenkov, A N; Ilic, D; Kollatschny, W; Kovacevic, A; Valdes, J R; Patino-Alvarez, V; Leon-Tavares, J; Torrealba, J; Zhdanova, V E

    2016-01-01

    We report the results of the first long-term (1990-2014) optical spectro-photometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift high-luminosity radio-quiet quasar. In the monitored period the continua and H$\\gamma$ fluxes changed for around two times, while the H$\\beta$ flux changed around 1.4 times. We found the periodical variations in the photometric flux with the periods of 1200, 1850 and 4000 days, and 4500 days periodicity in the spectroscopic variations. However, the periodicity of 4000-4500 days covers only one cycle of variation and should be confirmed with a longer monitoring campaign. There is an indication of the period around 1300 days in the spectroscopic light curves, but with small significance level, while the 1850 days period could not be clearly identified in the spectroscopic light curves. The line profiles have not significantly changed, showing an important red asymmetry and broad line peak redshifted around +1000 km s$^{-1}$. However, H$\\beta$ shows broade...

  20. Very Low-Mass Stellar and Substellar Companions to Solar-like Stars From MARVELS VI: A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646

    CERN Document Server

    Ma, Bo; Wolszczan, Alex; Muterspaugh, Matthew W; Lee, Brian; Henry, Gregory W; Schneider, Donald P; Martin, Eduardo L; Niedzielski, Andrzej; Xie, Jiwei; Fleming, Scott W; Thomas, Neil; Williamson, Michael; Zhu, Zhaohuan; Agol, Eric; Bizyaev, Dmitry; da Costa, Luiz Nicolaci; Jiang, Peng; Fiorenzano, A F Martinez; Hernandez, Jonay I Gonzalez; Guo, Pengcheng; Grieves, Nolan; Li, Rui; Liu, Jane; Mahadevan, Suvrath; Mazeh, Tsevi; Nguyen, Duy Cuong; Paegert, Martin; Sithajan, Sirinrat; Stassun, Keivan; Thirupathi, Sivarani; van Eyken, Julian C; Wan, Xiaoke; Wang, Ji; Wisniewski, John P; Zhao, Bo; Zucker, Shay

    2016-01-01

    We report the detections of a giant planet (MARVELS-7b) and a brown dwarf candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. It is the first close binary system with more than one substellar circum-primary companion discovered to the best of our knowledge. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using ET at Kitt Peak National Observatory, HRS at HET, the "Classic" spectrograph at the Automatic Spectroscopic Telescope at Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period brown dwarf in this binary. HD 87646 is a close binary with a separation of $\\sim22$ AU between the two stars, estimated using the Hipparcos catalogue and our newly acquired AO image from PALAO on the 200-inch Hale Telescope at Palomar. The primary star in the binary, HD 87646...

  1. THE QUASAR SDSS J153636.22+044127.0: A DOUBLE-PEAKED EMITTER IN A CANDIDATE BINARY BLACK HOLE SYSTEM

    International Nuclear Information System (INIS)

    Double-peaked emission lines are believed to be originated from accretion disks around supermassive black holes (SMBHs), and about 3% of z < 0.33 active galactic nuclei (AGNs) are found to be double-peaked emitters. The quasar SDSS J153636.22+044127.0 has recently been identified with peculiar broad-line emission systems exhibiting multiple redshifts. We decompose the Hα and Hβ profiles into a circular Keplerian disk-line component and other Gaussian components. We propose that the system is both a double-peaked emitter and a binary SMBH system, where the extra flux in the blue peaks of the broad lines comes from the region around the secondary black hole. We suggest that such black hole binary systems might also exist in many known double-peaked emitters, where the tidal torques from the secondary black hole clear the outer region of the disk around the primary black hole, similar to the gap in a protostellar disk due to the process of planetary migration, and might also stimulate the formation of a vertical extended source in the inner region around the primary which illuminates the disk. However, most secondary SMBHs in such systems might be too small to maintain a detectable broad-line region (BLR), so that the disk line from the primary dominates.

  2. A Periodically Varying Luminous Quasar at z=2 from the Pan-STARRS1 Medium Deep Survey: A Candidate Supermassive Black Hole Binary in the Gravitational Wave-Driven Regime

    CERN Document Server

    Liu, Tingting; Heinis, Sebastien; Magnier, Eugene A; Burgett, William S; Chambers, Kenneth; Flewelling, Heather; Huber, Mark; Hodapp, Klaus W; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Tonry, John L; Wainscoat, Richard J; Waters, Christopher

    2015-01-01

    Supermassive black hole binaries (SMBHBs) should be an inevitable consequence of the hierarchical growth of massive galaxies through mergers, and the strongest sirens of gravitational waves (GWs) in the cosmos. And yet, their direct detection has remained elusive due to the compact (sub-parsec) orbital separations of gravitationally bound SMBHBs. Here we exploit a theoretically predicted signature of a SMBHB in the time domain: periodic variability caused by a mass accretion rate that is modulated by the binary's orbital motion. We report our first significant periodically varying quasar detection from the systematic search in the Pan-STARRS1 (PS1) Medium Deep Survey. Our SMBHB candidate, PSO J334.2028+01.4075, is a luminous radio-loud quasar at $z=2.060$, with extended baseline photometry from the Catalina Real-Time Transient Survey, as well as archival spectroscopy from the FIRST Bright Quasar Survey. The observed period ($542 \\pm 15$ days) and estimated black hole mass ($\\log (M_{\\rm BH}/M_\\odot) = 9.97 \\p...

  3. VERY LARGE TELESCOPE/X-SHOOTER SPECTROSCOPY OF THE CANDIDATE BLACK HOLE X-RAY BINARY MAXI J1659-152 IN OUTBURST

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Ramanpreet; Kaper, Lex; Ellerbroek, Lucas E.; Russell, David M.; Altamirano, Diego; Wijnands, Rudy; Yang Yijung; Van der Horst, Alexander; Van der Klis, Michiel [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); D' Avanzo, Paolo [INAF, Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (Italy); De Ugarte Postigo, Antonio; Fynbo, Johan P. U. [Dark Cosmology Centre, Niels Bohr Institute, Juliane Maries Vej 30, Copenhagen 2100 (Denmark); Flores, Hector [GEPI, Paris Observatory, CNRS, University of Paris-Diderot, 5 Place Jules Janssen, 92195 Meudon (France); Goldoni, Paolo [Laboratoire Astroparticule et Cosmologie, 10 rue A. Domon et L. Duquet, 75205 Paris Cedex 13 (France); Thoene, Christina C. [IAA-CSIC, Glorieta de la Astronomia s/n, 18008 Granada (Spain); Kouveliotou, Chryssa [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Wiersema, Klaas [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Kuulkers, Erik, E-mail: r.kaur@uva.nl [European Space Agency, European Space Astronomy Centre, P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain)

    2012-02-20

    We present the optical to near-infrared spectrum of MAXI J1659-152 during the onset of its 2010 X-ray outburst. The spectrum was obtained with X-shooter on the ESO Very Large Telescope early in the outburst simultaneous with high-quality observations at both shorter and longer wavelengths. At the time of the observations, the source was in the low-hard state. The X-shooter spectrum includes many broad ({approx}2000 km s{sup -1}), double-peaked emission profiles of H, He I, and He II, characteristic signatures of a low-mass X-ray binary during outburst. We detect no spectral signatures of the low-mass companion star. The strength of the diffuse interstellar bands results in a lower limit to the total interstellar extinction of A{sub V} {approx_equal} 0.4 mag. Using the neutral hydrogen column density obtained from the X-ray spectrum we estimate A{sub V} {approx_equal} 1 mag. The radial velocity structure of the interstellar Na I D and Ca II H and K lines results in a lower limit to the distance of {approx}4 {+-} 1 kpc, consistent with previous estimates. With this distance and A{sub V} , the dereddened spectral energy distribution represents a flat disk spectrum. The two 10 minute X-shooter spectra show significant variability in the red wing of the emission-line profiles, indicating a global change in the density structure of the disk, though on a timescale much shorter than the typical viscous timescale of the disk.

  4. VERY LARGE TELESCOPE/X-SHOOTER SPECTROSCOPY OF THE CANDIDATE BLACK HOLE X-RAY BINARY MAXI J1659-152 IN OUTBURST

    International Nuclear Information System (INIS)

    We present the optical to near-infrared spectrum of MAXI J1659-152 during the onset of its 2010 X-ray outburst. The spectrum was obtained with X-shooter on the ESO Very Large Telescope early in the outburst simultaneous with high-quality observations at both shorter and longer wavelengths. At the time of the observations, the source was in the low-hard state. The X-shooter spectrum includes many broad (∼2000 km s–1), double-peaked emission profiles of H, He I, and He II, characteristic signatures of a low-mass X-ray binary during outburst. We detect no spectral signatures of the low-mass companion star. The strength of the diffuse interstellar bands results in a lower limit to the total interstellar extinction of AV ≅ 0.4 mag. Using the neutral hydrogen column density obtained from the X-ray spectrum we estimate AV ≅ 1 mag. The radial velocity structure of the interstellar Na I D and Ca II H and K lines results in a lower limit to the distance of ∼4 ± 1 kpc, consistent with previous estimates. With this distance and AV , the dereddened spectral energy distribution represents a flat disk spectrum. The two 10 minute X-shooter spectra show significant variability in the red wing of the emission-line profiles, indicating a global change in the density structure of the disk, though on a timescale much shorter than the typical viscous timescale of the disk.

  5. Calibration Binaries

    Science.gov (United States)

    Drummond, J.

    2011-09-01

    Two Excel Spreadsheet files are offered to help calibrate telescope or camera image scale and orientation with binary stars for any time. One is a personally selected list of fixed position binaries and binaries with well-determined orbits, and the other contains all binaries with published orbits. Both are derived from the web site of the Washington Double Star Library. The spreadsheets give the position angle and separation of the binaries for any entered time by taking advantage of Excel's built in iteration function to solve Kepler's transcendental equation.

  6. The Candidate

    OpenAIRE

    Osborn, John C

    2013-01-01

    ABSTRACT   The Candidate is an attempt to marry elements of journalism and gaming into a format that both entertains and educates the player. The Google-AP Scholarship, a new scholarship award that is given to several journalists a year to work on projects at the threshold of technology and journalism, funded the project. The objective in this prototype version of the game is to put the player in the shoes of a congressional candidate during an off-year election, specificall...

  7. 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.

  8. 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.

  9. Gravitational waves from inspiralling binary black holes

    International Nuclear Information System (INIS)

    Binary black holes are the most promising candidate sources for the first generation of earth-based interferometric gravitational-wave detectors. We summarize and discuss the state-of-the-art analytical techniques developed during the last few years to better describe the late dynamical evolution of binary black holes of comparable masses

  10. Binary Planets

    Science.gov (United States)

    Ryan, Keegan; Nakajima, Miki; Stevenson, David J.

    2014-11-01

    Can a bound pair of similar mass terrestrial planets exist? We are interested here in bodies with a mass ratio of ~ 3:1 or less (so Pluto/Charon or Earth/Moon do not qualify) and we do not regard the absence of any such discoveries in the Kepler data set to be significant since the tidal decay and merger of a close binary is prohibitively fast well inside of 1AU. SPH simulations of equal mass “Earths” were carried out to seek an answer to this question, assuming encounters that were only slightly more energetic than parabolic (zero energy). We were interested in whether the collision or near collision of two similar mass bodies would lead to a binary in which the two bodies remain largely intact, effectively a tidal capture hypothesis though with the tidal distortion being very large. Necessarily, the angular momentum of such an encounter will lead to bodies separated by only a few planetary radii if capture occurs. Consistent with previous work, mostly by Canup, we find that most impacts are disruptive, leading to a dominant mass body surrounded by a disk from which a secondary forms whose mass is small compared to the primary, hence not a binary planet by our adopted definition. However, larger impact parameter “kissing” collisions were found to produce binaries because the dissipation upon first encounter was sufficient to provide a bound orbit that was then rung down by tides to an end state where the planets are only a few planetary radii apart. The long computational times for these simulation make it difficult to fully map the phase space of encounters for which this outcome is likely but the indications are that the probability is not vanishingly small and since planetary encounters are a plausible part of planet formation, we expect binary planets to exist and be a non-negligible fraction of the larger orbital radius exoplanets awaiting discovery.

  11. Properties of M31. V: 298 Eclipsing Binaries from PAndromeda

    CERN Document Server

    Lee, C -H; Seitz, S; Bender, R; Riffeser, A; Kodric, M; Hopp, U; Snigula, J; Goessl, C; Kudritzki, R -P; Burgett, W; Chambers, K; Hodapp, K; Kaiser, N; Waters, C

    2014-01-01

    The goal of this work is to conduct a photometric study of eclipsing binaries in M31. We apply a modified box-fitting algorithm to search for eclipsing binary candidates and determine their period. We classify these candidates into detached, semi-detached, and contact systems using the Fourier decomposition method. We cross-match the position of our detached candidates with the photometry from Local Group Survey (Massey et al. 2006) and select 13 candidates brighter than 20.5 magnitude in V. The relative physical parameters of these detached candidates are further characterized with Detached Eclipsing Binary Light curve fitter (DEBiL) by Devor (2005). We will followup the detached eclipsing binaries spectroscopically and determine the distance to M31.

  12. Binary classification of items of interest in a repeatable process

    Science.gov (United States)

    Abell, Jeffrey A.; Spicer, John Patrick; Wincek, Michael Anthony; Wang, Hui; Chakraborty, Debejyo

    2014-06-24

    A system includes host and learning machines in electrical communication with sensors positioned with respect to an item of interest, e.g., a weld, and memory. The host executes instructions from memory to predict a binary quality status of the item. The learning machine receives signals from the sensor(s), identifies candidate features, and extracts features from the candidates that are more predictive of the binary quality status relative to other candidate features. The learning machine maps the extracted features to a dimensional space that includes most of the items from a passing binary class and excludes all or most of the items from a failing binary class. The host also compares the received signals for a subsequent item of interest to the dimensional space to thereby predict, in real time, the binary quality status of the subsequent item of interest.

  13. Red-giant stars in eccentric binaries

    Directory of Open Access Journals (Sweden)

    Beck P. G.

    2015-01-01

    Full Text Available The unparalleled photometric data obtained by NASA’s Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like oscillating red-giant primary component. We also report several new binary systems that are candidates for hosting an oscillating companion. A powerful approach to study binary stars is to combine asteroseimic techniques with light curve fitting. Seismology allows us to deduce the properties of red giants. In addition, by modeling the ellipsoidal modulations we can constrain the parameters of the binary system. An valuable independent source are ground-bases, high-resolution spectrographs.

  14. 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...... of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q ~ 0.1, making the companion of the lens a strong brown dwarf candidate....

  15. Binary effectivity rules

    DEFF Research Database (Denmark)

    Keiding, Hans; Peleg, Bezalel

    2006-01-01

    Abstract  A social choice rule (SCR) is a collection of social choice correspondences, one for each agenda. An effectivity rule is a collection of effectivity functions, one for each agenda. We prove that every monotonic and superadditive effectivity rule is the effectivity rule of some SCR. A SCR...... 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...... effectivity rule is regular if it is the effectivity rule of some regular binary SCR. We characterize completely the family of regular binary effectivity rules. Quite surprisingly, intrinsically defined von Neumann-Morgenstern solutions play an important role in this characterization...

  16. Eclipsing binaries in open clusters

    DEFF Research Database (Denmark)

    Southworth, John; Clausen, J.V.

    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...

  17. Ultra-short period binaries from the Catalina Surveys

    International Nuclear Information System (INIS)

    We investigate the properties of 367 ultra-short period binary candidates selected from 31,000 sources recently identified from Catalina Surveys data. Based on light curve morphology, along with WISE, Sloan Digital Sky Survey, and GALEX multi-color photometry, we identify two distinct groups of binaries with periods below the 0.22 day contact binary minimum. In contrast to most recent work, we spectroscopically confirm the existence of M dwarf+M dwarf contact binary systems. By measuring the radial velocity variations for five of the shortest-period systems, we find examples of rare cool white dwarf (WD)+M dwarf binaries. Only a few such systems are currently known. Unlike warmer WD systems, their UV flux and optical colors and spectra are dominated by the M-dwarf companion. We contrast our discoveries with previous photometrically selected ultra-short period contact binary candidates and highlight the ongoing need for confirmation using spectra and associated radial velocity measurements. Overall, our analysis increases the number of ultra-short period contact binary candidates by more than an order of magnitude.

  18. Globular Clusters Hosting Intermediate-Mass Black Holes: No Mass-Segregation Based Candidates

    Science.gov (United States)

    Pasquato, Mario; Miocchi, Paolo; Won, Sohn Bong; Lee, Young-Wook

    2016-06-01

    Recently, both stellar mass segregation and binary fractions were uniformly measured on relatively large samples of Galactic globular clusters (GCs). Simulations show that both sizable binary-star populations and intermediate-mass black holes (IMBHs) quench mass segregation in relaxed GCs. Thus mass segregation in GCs with a reliable binary-fraction measurement is a valuable probe to constrain IMBHs. In this paper we combine mass-segregation and binary-fraction measurements from the literature to build a sample of 33 GCs (with measured core binary fractions), and a sample of 43 GCs (with binary-fraction measurements in the area between the core radius and the half-mass radius). Within both samples we try to identify IMBH-host candidates. These should have relatively low mass segregation, a low binary fraction (segregated (and show a larger binary fraction), confirming the theoretical expectation that the energy sources responsible for the large core are also quenching mass segregation.

  19. Binary compact object inspiral: Detection expectations

    Indian Academy of Sciences (India)

    Vassiliki Kalogera

    2004-10-01

    We review the current estimates of binary compact object inspiral rates in particular in view of the recently discovered highly relativistic binary pulsar J0737-3039. One of the robust results is that, because of this discovery, the rate estimates for binary neutron stars have increased by a factor of 6-7 independent of any uncertainties related to the pulsar population properties. This rate increase has dramatic implications for gravitational wave detectors. For initial LIGO, the most probable detection rates for double neutron star (DNS) inspirals is 1 event/(5{250) yr; at 95% confidence we obtain rates up to 1/1.5 yr. For advanced LIGO, the most probable rates are 20-1000 events/yr. These predictions, for the first time, bring the expectations for DNS detections by initial LIGO to the astrophysically relevant regime. We also use our models to predict that the large-scale Parkes multibeam pulsar survey with acceleration searches could detect an average of three to four binary pulsars similar to those known at present. In comparison, rate estimates for binaries with black holes are derived based on binary evolution calculation, and based on the optimistic ends of the ranges, remain an important candidate for inspiral detection in the next few years. We also consider another aspect of the detectability of binary inspiral: the effect of precession on the detection efficiency of astrophysically relevant binaries. Based on our current astrophysical expectations, large tilt angles are not favored. As a result the decrease in detection rate varies rather slowly with black hole spin magnitude and is within 20-30% of the maximum possible values.

  20. PHOEBE: PHysics Of Eclipsing BinariEs

    Science.gov (United States)

    Prsa, Andrej; Matijevic, Gal; Latkovic, Olivera; Vilardell, Francesc; Wils, Patrick

    2011-06-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program (Wilson & Devinney 1971). This introductory paper overviews most important scientific extensions (incorporating observational spectra of eclipsing binaries into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining and proper treatment of the reddening), numerical innovations (suggested improvements to WD's Differential Corrections method, the new Nelder & Mead's downhill Simplex method) and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability.

  1. Multiples among detached eclipsing binaries from the ASAS catalog

    CERN Document Server

    Hełminiak, K G; Ratajczak, M; Jordán, A; Espinoza, N; Brahm, R; Kambe, E; Ukita, N

    2015-01-01

    For more than three years now we have been conducting a spectroscopic survey of detached eclipsing binaries (DEBs) from the All-Sky Automated Survey (ASAS) database. Thousands of high-resolution spectra of over 300 systems were secured, and used for radial velocity measurements and spectral analysis. In our sample we found a zoo of multiple systems, such as spectroscopic triples and quadruples, visual binaries with eclipsing components, and circumbinary low-mass companions, including sub-stellar-mass candidates

  2. Encounters of binaries

    International Nuclear Information System (INIS)

    Numerical integrations of encounters of pairs of binaries have been used to study the class of interactions, called fly-bys, in which the two-binary configuration survives. It is shown that these typically weak interactions can be treated by means of a first-order perturbation theory. A simple simulation model for obtaining the energy transfer rate between various degrees of freedom has been constructed. The model was employed to estimate the additional energy transfer arising from impact parameters larger than those used in the numerical experiments. In the hard binary limit the total energy transfer caused by binary-binary encounters is dominated by the collisional interactions in which the two-binary configuration is destroyed. (author)

  3. Chromospheric emission of planet candidate systems - a way to identify false positives

    CERN Document Server

    Karoff, Christoffer; Boxano, Alfio; Knudsen, Mads Faurschou

    2016-01-01

    It has been hypothesized that the presence of closely orbiting giant planets is associated with enhanced chromospheric emission of their host stars. The main cause for such a relation would likely be enhanced dynamo action induced by the planet. We present measurements of chromospheric emission in 234 planet candidate systems from the Kepler mission. This ensemble includes 37 systems with giant planet candidates, which show a clear emission enhancement. The enhancement, however, disappears when systems which are also identified as eclipsing binary candidates are removed from the ensemble. This suggests that a large fraction of the giant planet candidate systems with chromospheric emission stronger than the Sun are not giant planet system, but false positives. Such false-positive systems could be tidally interacting binaries with strong chromospheric emission. This hypotesis is supported by an analysis of 188 eclipsing binary candidates that show increasing chromospheric emission as function of decreasing orbi...

  4. Massive Black Hole Binaries: Dynamical Evolution and Observational Signatures

    Directory of Open Access Journals (Sweden)

    M. Dotti

    2012-01-01

    Full Text Available The study of the dynamical evolution of massive black hole pairs in mergers is crucial in the context of a hierarchical galaxy formation scenario. The timescales for the formation and the coalescence of black hole binaries are still poorly constrained, resulting in large uncertainties in the expected rate of massive black hole binaries detectable in the electromagnetic and gravitational wave spectra. Here, we review the current theoretical understanding of the black hole pairing in galaxy mergers, with a particular attention to recent developments and open issues. We conclude with a review of the expected observational signatures of massive binaries and of the candidates discussed in literature to date.

  5. 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

  6. Accessibility of the Gravitational-Wave Background due to Binary Coalescences to Second and Third Generation Gravitational-Wave Detectors

    OpenAIRE

    Wu, Chengjian; Mandic, Vuk; Regimbau, Tania

    2011-01-01

    Compact binary coalescences, such as binary neutron stars or black holes, are among the most promising candidate sources for the current and future terrestrial gravitational-wave detectors. While such sources are best searched using matched template techniques and chirp template banks, integrating chirp signals from binaries over the entire Universe also leads to a gravitational-wave background (GWB). In this paper we systematically scan the parameter space for the binary coalescence GWB mode...

  7. Polarization in binary microlensing events

    CERN Document Server

    Ingrosso, G; Nucita, A A; Strafella, F; Novati, S Calchi; Jetzer, Ph; Liuzzi, G; Zakharov, A

    2013-01-01

    The light received by source stars in microlensing events may be significantly polarized if both an efficient photon scattering mechanism is active in the source stellar atmosphere and a differential magnification is therein induced by the lensing system. The best candidate events for observing polarization are highly magnified events with source stars belonging to the class of cool, giant stars {in which the stellar light is polarized by photon scattering on dust grains contained in their envelopes. The presence in the stellar atmosphere of an internal cavity devoid of dust produces polarization profiles with a two peaks structure. Hence, the time interval between them gives an important observable quantity directly related to the size of the internal cavity and to the model parameters of the lens system.} We show that {during a microlensing event} the expected polarization variability can solve an ambiguity, that arises in some cases, related to the binary or planetary lensing interpretation of the perturba...

  8. Polarization in binary microlensing events

    International Nuclear Information System (INIS)

    The light received by source stars in microlensing events may be significantly polarized if both an efficient photon-scattering mechanism is active in the source stellar atmosphere and a differential magnification is therein induced by the lensing system. The best candidate events for observing polarization are highly magnified events with source stars belonging to the class of cool, giant stars in which the stellar light is polarized by photon scattering on dust grains contained in their envelopes. The presence in the stellar atmosphere of an internal cavity devoid of dust produces polarization profiles with a two peaks structure. Hence, the time interval between them gives an important observable quantity directly related to the size of the internal cavity and to the model parameters of the lens system. We show that, during a microlensing event, the expected polarization variability can solve an ambiguity that arises in some cases, related to the binary or planetary lensing interpretation of the perturbations observed near the maximum of the event light-curve. We consider a specific event case for which the parameter values corresponding to the two solutions are given. Then, assuming a polarization model for the source star, we compute the two expected polarization profiles. The position of the two peaks appearing in the polarization curves and the characteristic time interval between them allow us to distinguish between the binary and planetary lens solutions. (paper)

  9. Computational selection and prioritization of candidate genes for Fetal Alcohol Syndrome

    Directory of Open Access Journals (Sweden)

    Hide Winston

    2007-10-01

    Full Text Available Abstract Background Fetal alcohol syndrome (FAS is a serious global health problem and is observed at high frequencies in certain South African communities. Although in utero alcohol exposure is the primary trigger, there is evidence for genetic- and other susceptibility factors in FAS development. No genome-wide association or linkage studies have been performed for FAS, making computational selection and -prioritization of candidate disease genes an attractive approach. Results 10174 Candidate genes were initially selected from the whole genome using a previously described method, which selects candidate genes according to their expression in disease-affected tissues. Hereafter candidates were prioritized for experimental investigation by investigating criteria pertinent to FAS and binary filtering. 29 Criteria were assessed by mining various database sources to populate criteria-specific gene lists. Candidate genes were then prioritized for experimental investigation using a binary system that assessed the criteria gene lists against the candidate list, and candidate genes were scored accordingly. A group of 87 genes was prioritized as candidates and for future experimental validation. The validity of the binary prioritization method was assessed by investigating the protein-protein interactions, functional enrichment and common promoter element binding sites of the top-ranked genes. Conclusion This analysis highlighted a list of strong candidate genes from the TGF-β, MAPK and Hedgehog signalling pathways, which are all integral to fetal development and potential targets for alcohol's teratogenic effect. We conclude that this novel bioinformatics approach effectively prioritizes credible candidate genes for further experimental analysis.

  10. Massive Stars in Interactive Binaries

    Science.gov (United States)

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

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

  11. Globular clusters hosting intermediate-mass black-holes: no mass-segregation based candidates

    CERN Document Server

    Pasquato, Mario; Sohn, Bong Won; Lee, Young-Wook

    2016-01-01

    Recently, both stellar mass-segregation and binary-fractions were uniformly measured on relatively large samples of Galactic Globular Clusters (GCs). Simulations show that both sizeable binary-star populations and Intermediate-Mass Black Holes (IMBHs) quench mass-segregation in relaxed GCs. Thus mass-segregation in GCs with a reliable binary-fraction measurement is a valuable probe to constrain IMBHs. In this paper we combine mass-segregation and binary-fraction measurements from the literature to build a sample of 33 GCs (with measured core-binary fractions), and a sample of 43 GCs (with a binary fraction measurement in the area between the core radius and the half-mass radius). Within both samples we try to identify IMBH-host candidates. These should have relatively low mass-segregation, a low binary fraction (< 5%), and short (< 1 Gyr) relaxation time. Considering the core binary fraction sample, no suitable candidates emerge. If the binary fraction between the core and the half-mass radius is consid...

  12. The ELM Survey. VII. Orbital Properties of Low Mass White Dwarf Binaries

    CERN Document Server

    Brown, Warren R; Kilic, Mukremin; Kenyon, Scott J; Prieto, Carlos Allende

    2016-01-01

    We present the discovery of 15 extremely low mass (5 < log{g} < 7) white dwarf candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted ELM Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 Msun mean and 0.25 Msun dispersion. Thus extremely low mass white dwarfs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the white dwarf binaries have a total mass below the Chandrasekhar mass and thus are not Type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive white dwarfs and stable mass transfer AM CVn binaries.

  13. Binary Populations and Stellar Dynamics in Young Clusters

    Science.gov (United States)

    Vanbeveren, D.; Belkus, H.; Van Bever, J.; Mennekens, N.

    2008-06-01

    We first summarize work that has been done on the effects of binaries on theoretical population synthesis of stars and stellar phenomena. Next, we highlight the influence of stellar dynamics in young clusters by discussing a few candidate UFOs (unconventionally formed objects) like intermediate mass black holes, η Car, ζ Pup, γ2 Velorum and WR 140.

  14. Binary populations and stellar dynamics in young clusters

    CERN Document Server

    Vanbeveren, D; Van Bever, J; Mennekens, N

    2008-01-01

    We first summarize work that has been done on the effects of binaries on theoretical population synthesis of stars and stellar phenomena. Next, we highlight the influence of stellar dynamics in young clusters by discussing a few candidate UFOs (unconventionally formed objects) like intermediate mass black holes, Eta Carinae, Zeta Puppis, Gamma Velorum and WR 140.

  15. SOPHIE velocimetry of Kepler transit candidates VI. A false positive rate of 35% for Kepler close-in giant candidates

    CERN Document Server

    Santerne, A; Moutou, C; Bouchy, F; Hébrard, G; Almenara, J -M; Bonomo, A S; Deleuil, M; Santos, N C

    2012-01-01

    The false positive probability (FPP) of Kepler transiting candidates is a key value for statistical studies of candidate properties. An investigation of the stellar population in the Kepler field by Morton & Johnson (2011) has provided an estimation for the FPP of less than 5% for most of the candidates. We report here the results of our radial velocity observations on a sample of 46 Kepler candidates with transit depth greater than 0.4%, orbital period less than 25 days and host star brighter than Kepler magnitude 14.7. We used the SOPHIE spectrograph mounted on the 1.93-m telescope at the Observatoire de Haute-Provence to establish the nature of the transiting candidates. In this sample, we found 5 undiluted eclipsing binaries, 2 brown dwarfs, 6 diluted eclipsing binaries and 9 new transiting planets that complete the 11 already published. The remaining 13 candidates were not followed up or remain unsolved due to photon noise limitation or lack of observations. From these results we compute the FPP for ...

  16. The binary proletariat

    OpenAIRE

    Bolt, Nate

    2000-01-01

    In the endless quest to transform itself, capitalism has spawned a new working class. The proletariat was an essential product of the industrial revolution, and the lighter, more efficient capitalism of the digital revolution has created the Binary Proletariat.

  17. Performance analysis and binary working fluid selection of combined flash-binary geothermal cycle

    International Nuclear Information System (INIS)

    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. Eclipsing Binary Pulsars

    CERN Document Server

    Freire, P C C

    2004-01-01

    The first eclipsing binary pulsar, PSR B1957+20, was discovered in 1987. Since then, 13 other eclipsing low-mass binary pulsars have been found, 12 of these are in globular clusters. In this paper we list the known eclipsing binary pulsars and their properties, with special attention to the eclipsing systems in 47 Tuc. We find that there are two fundamentally different groups of eclipsing binary pulsars; separated by their companion masses. The less massive systems (M_c ~ 0.02 M_sun) are a product of predictable stellar evolution in binary pulsars. The systems with more massive companions (M_c ~ 0.2 M_sun) were formed by exchange encounters in globular clusters, and for that reason are exclusive to those environments. This class of systems can be used to learn about the neutron star recycling fraction in the globular clusters actively forming pulsars. We suggest that most of these binary systems are undetectable at radio wavelengths.

  19. Binary Evolutionary Models

    CERN Document Server

    Han, Z

    2008-01-01

    In this talk, we present the general principles of binary evolution and give two examples. The first example is the formation of subdwarf B stars (sdBs) and their application to the long-standing problem of ultraviolet excess (also known as UV-upturn) in elliptical galaxies. The second is for the progenitors of type Ia supernovae (SNe Ia). We discuss the main binary interactions, i.e., stable Roche lobe overflow (RLOF) and common envelope (CE) evolution, and show evolutionary channels leading to the formation of various binary-related objects. In the first example, we show that the binary model of sdB stars of Han et al. (2002, 2003) can reproduce field sdB stars and their counterparts, extreme horizontal branch (EHB) stars, in globular clusters. By applying the binary model to the study of evolutionary population synthesis, we have obtained an ``a priori'' model for the UV-upturn of elliptical galaxies and showed that the UV-upturn is most likely resulted from binary interactions. This has major implications...

  20. Hunting for brown dwarf binaries and testing atmospheric models with X-Shooter

    CERN Document Server

    Manjavacas, E; Alcalá, J M; Zapatero-Osorio, M R; Béjar, V J S; Homeier, D; Bonnefoy, M; Smart, R L; Henning, T; Allard, F

    2015-01-01

    The determination of the brown dwarf binary fraction may contribute to the understanding of the substellar formation mechanisms. Unresolved brown dwarf binaries may be revealed through their peculiar spectra or the discrepancy between optical and near-infrared spectral type classification. We obtained medium-resolution spectra of 22 brown dwarfs with these characteristics using the X-Shooter spectrograph at the VLT. We aimed to identify brown dwarf binary candidates, and to test if the BT-Settl 2014 atmospheric models reproduce their observed spectra. To find binaries spanning the L-T boundary, we used spectral indices and compared the spectra of the selected candidates to single spectra and synthetic binary spectra. We used synthetic binary spectra with components of same spectral type to determine as well the sensitivity of the method to this class of binaries. We identified three candidates to be combination of L plus T brown dwarfs. We are not able to identify binaries with components of similar spectral ...

  1. SEARCH FOR SUPERMASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

    International Nuclear Information System (INIS)

    Supermassive black hole (SMBH) binaries are expected in a ΛCDM cosmology given that most (if not all) massive galaxies contain a massive black hole (BH) at their center. So far, however, direct evidence for such binaries has been elusive. We use cross-correlation to search for temporal velocity shifts in the Mg II broad emission lines of 0.36 9 M☉ BHs in SMBH binaries, we are sensitive to velocity drifts for binary separations of ∼0.1 pc with orbital periods of ∼100 yr. We find seven candidate sub-parsec-scale binaries with velocity shifts >3.4σ ∼ 280 km s–1, where σ is our systematic error. Comparing the detectability of SMBH binaries with the number of candidates (N ≤ 7), we can rule out that most 109 M☉ BHs exist in ∼0.03-0.2 pc scale binaries, in a scenario where binaries stall at sub-parsec scales for a Hubble time. We further constrain that ≤16% (one-third) of quasars host SMBH binaries after considering gas-assisted sub-parsec evolution of SMBH binaries, although this result is very sensitive to the assumed size of the broad line region. We estimate the detectability of SMBH binaries with ongoing or next-generation surveys (e.g., Baryon Oscillation Spectroscopic Survey, Subaru Prime Focus Spectrograph), taking into account the evolution of the sub-parsec binary in circumbinary gas disks. These future observations will provide longer time baselines for searches similar to ours and may in turn constrain the evolutionary scenarios of SMBH binaries

  2. Binary Neutron Star Mergers

    Directory of Open Access Journals (Sweden)

    Joshua A. Faber

    2012-07-01

    Full Text Available We review the current status of studies of the coalescence of binary neutron star systems. We begin with a discussion of the formation channels of merging binaries and we discuss the most recent theoretical predictions for merger rates. Next, we turn to the quasi-equilibrium formalisms that are used to study binaries prior to the merger phase and to generate initial data for fully dynamical simulations. The quasi-equilibrium approximation has played a key role in developing our understanding of the physics of binary coalescence and, in particular, of the orbital instability processes that can drive binaries to merger at the end of their lifetimes. We then turn to the numerical techniques used in dynamical simulations, including relativistic formalisms, (magneto-hydrodynamics, gravitational-wave extraction techniques, and nuclear microphysics treatments. This is followed by a summary of the simulations performed across the field to date, including the most recent results from both fully relativistic and microphysically detailed simulations. Finally, we discuss the likely directions for the field as we transition from the first to the second generation of gravitational-wave interferometers and while supercomputers reach the petascale frontier.

  3. 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...

  4. Interim results from the ongoing hunt for supermassive black hole binaries

    Science.gov (United States)

    Runnoe, Jessie C.; Mathes, Gavin; Pennell, Alison; Brown, Stephanie Meghan; Eracleous, Michael; Boroson, Todd A.; Bogdanovic, Tamara; Sigurdsson, Steinn; Halpern, Jules P.; Liu, Jia

    2016-01-01

    Supermassive black hole binaries seem to be an inevitable product of the prevailing galaxy evolution scenarios in which most massive galaxies play host to a central black hole and undergo a history of mergers and accretion over the course of cosmic time. The early stages of this process have been observed in the form of interacting galaxy pairs as well dual active galactic nuclei with kilo-parsec separations, but detections of the close, bound binaries that are expected to follow have proven elusive. With this motivation, we have been conducting a systematic observational search for sub-parsec separation supermassive black hole binaries. Specifically, we test the hypothesis that the secondary black hole in the system is active and the resulting broad emission lines are doppler shifted due to orbital motion in the binary (analogous to a single-line spectroscopc binary star). Our sample includes 88 binary candidates selected from z1000 km/s) of their broad Hβ emission lines relative to their systemic redshifts. I will present the latest results from the spectroscopic monitoring campaign that we are conducting to constrain the nature of the binary candidates. These include the radial velocity curves, which now use observations made through 2015, and the constraints that can be placed on the physical properties of the binary based on the radial velocity curves and observed flux variability of the binaries.

  5. Binary Popldation Synthcsis Study

    Institute of Scientific and Technical Information of China (English)

    HAN Zhanwen

    2011-01-01

    Binary population synthesis (BPS), an approach to evolving millions of stars (including binaries) simultaneously, plays a crucial role in our understanding of stellar physics, the structure and evolution of galaxies, and cosmology. We proposed and developed a BPS approach, and used it to investigate the formation of many peculiar stars such as hot subdwarf stars, progenitors of type la supernovae, barium stars, CH stars, planetary nebulae, double white dwarfs, blue stragglers, contact binaries, etc. We also established an evolution population synthesis (EPS) model, the Yunnan Model, which takes into account binary interactions for the first time. We applied our model for the origin of hot subdwarf stars in the study of elliptical galaxies and explained their far-UV radiation.

  6. 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.

  7. Binary and Millisecond Pulsars

    CERN Document Server

    Lorimer, D 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 solar masses, 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.

  8. Hypervelocity binary stars: smoking gun of massive binary black holes

    CERN Document Server

    Lu, Youjun; Lin, D N C

    2007-01-01

    The hypervelocity stars recently found in the Galactic halo are expelled from the Galactic center through interactions between binary stars and the central massive black hole or between single stars and a hypothetical massive binary black hole. In this paper, we demonstrate that binary stars can be ejected out of the Galactic center with velocities up to 10^3 km/s, while preserving their integrity, through interactions with a massive binary black hole. Binary stars are unlikely to attain such high velocities via scattering by a single massive black hole or through any other mechanisms. Based on the above theoretical prediction, we propose a search for binary systems among the hypervelocity stars. Discovery of hypervelocity binary stars, even one, is a definitive evidence of the existence of a massive binary black hole in the Galactic center.

  9. Milli-arcsecond Binaries

    CERN Document Server

    Torres, R M; Mioduszewki, A; Rodríguez, L F

    2008-01-01

    As part of an astrometric program, we have used the Very Long Baseline Array to measure the trigonometric parallax of several young stars in the Taurus and Ophiuchus star-forming regions with great accuracy. Additionally, we have obtained an unprecedented sample of high-resolution (~ 1 mas) images of several young stellar systems. These images revealed that about 70% of the stars in our sample are very tight binary stars (with separations of a few mas). Since it is highly unlikely that 70% of all stars are such tight binaries, we argue that selection effects are at work.

  10. Binary Cumulant Varieties

    CERN Document Server

    Sturmfels, Bernd

    2011-01-01

    Algebraic statistics for binary random variables is concerned with highly structured algebraic varieties in the space of 2x2x...x2-tensors. We demonstrate the advantages of representing such varieties in the coordinate system of binary cumulants. Our primary focus lies on hidden subset models. Parametrizations and implicit equations in cumulants are derived for hyperdeterminants, for secant and tangential varieties of Segre varieties, and for certain context-specific independence models. Extending work of Rota and collaborators, we explore the polynomial inequalities satisfied by cumulants.

  11. Dark matter candidates

    International Nuclear Information System (INIS)

    One of the simplest, yet most profound, questions we can ask about the Universe is, how much stuff is in it, and further what is that stuff composed of? Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation. Remarkably, at this late date in the history of the Universe we still do not have a definitive answer to this simplest of questions---although we have some very intriguing clues. It is known with certainty that most of the material in the Universe is dark, and we have the strong suspicion that the dominant component of material in the Cosmos is not baryons, but rather is exotic relic elementary particles left over from the earliest, very hot epoch of the Universe. If true, the Dark Matter question is a most fundamental one facing both particle physics and cosmology. The leading particle dark matter candidates are: the axion, the neutralino, and a light neutrino species. All three candidates are accessible to experimental tests, and experiments are now in progress. In addition, there are several dark horse, long shot, candidates, including the superheavy magnetic monopole and soliton stars. 13 refs

  12. Supermassive Black Hole Binaries: Environment and Galaxy Host Properties of PTA and eLISA sources

    CERN Document Server

    Palafox, Eva Martínez; Colín, Pedro; Gottlöber, Stefan

    2014-01-01

    Supermassive black hole (BH) binaries would comprise the strongest sources of gravitational waves (GW) once they reach <<1 pc separations, for both pulsar timing arrays (PTAs) and space based (SB) detectors. While BH binaries coalescences constitute a natural outcome of the cosmological standard model and galaxy mergers, their dynamical evolution is still poorly understood and therefore their abundances at different stages. We use a dynamical model for the decay of BH binaries coupled with a cosmological simulation and semi-empirical approaches to the occupation of haloes by galaxies and BHs, in order to follow the evolution of the properties distribution of galaxies hosting BH binaries candidates to decay due to GWs emission. Our models allow us to relax simplifying hypothesis about the binaries occupation in galaxies and their mass, as well as redshift evolution. Following previously proposed electromagnetic (EM) signatures of binaries in the subpc regime, that include spectral features and variabilit...

  13. Formation of binary radio pulsars

    International Nuclear Information System (INIS)

    In the framework of the standard scenario of the evolution of massive binary stars a study is made of the formation of final binary systems in which at least one of the components is a neutron star. It is found that about every fortieth radio pulsar must be a member of a close binary system. This is confirmed by observations. Radio pulsars are not formed in wide binary systems, possibly because of the very slow rotation of the presupernova stars

  14. Compressing Binary Decision Diagrams

    DEFF Research Database (Denmark)

    Hansen, Esben Rune; Satti, Srinivasa Rao; Tiedemann, Peter

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1...

  15. Equational binary decision diagrams

    NARCIS (Netherlands)

    Groote, J.F.; Pol, J.C. van de

    2000-01-01

    We 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 tautology checkin

  16. Eclipsing Binaries From the CSTAR Project at Dome A, Antarctica

    CERN Document Server

    Yang, Ming; Wang, Songhu; Zhou, Ji-Lin; Zhou, Xu; Wang, Lingzhi; Wang, Lifan; Wittenmyer, R A; Liu, Hui-Gen; Meng, Zeyang; Ashley, M C B; Storey, J W V; Bayliss, D; Tinney, Chris; Wang, Ying; Wu, Donghong; Liang, Ensi; Yu, Zhouyi; Fan, Zhou; Feng, Long-Long; Gong, Xuefei; Lawrence, J S; Liu, Qiang; Luong-Van, D M; Ma, Jun; Wu, Zhenyu; Yan, Jun; Yang, Huigen; Yang, Ji; Yuan, Xiangyan; Zhang, Tianmeng; Zhu, Zhenxi; Zou, Hu

    2015-01-01

    The Chinese Small Telescope ARray (CSTAR) has observed an area around the Celestial South Pole at Dome A since 2008. About $20,000$ light curves in the i band were obtained lasting from March to July, 2008. The photometric precision achieves about 4 mmag at i = 7.5 and 20 mmag at i = 12 within a 30 s exposure time. These light curves are analyzed using Lomb--Scargle, Phase Dispersion Minimization, and Box Least Squares methods to search for periodic signals. False positives may appear as a variable signature caused by contaminating stars and the observation mode of CSTAR. Therefore the period and position of each variable candidate are checked to eliminate false positives. Eclipsing binaries are removed by visual inspection, frequency spectrum analysis and locally linear embedding technique. We identify 53 eclipsing binaries in the field of view of CSTAR, containing 24 detached binaries, 8 semi-detached binaries, 18 contact binaries, and 3 ellipsoidal variables. To derive the parameters of these binaries, we ...

  17. MICROLENSING BINARIES DISCOVERED THROUGH HIGH-MAGNIFICATION CHANNEL

    Energy Technology Data Exchange (ETDEWEB)

    Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Gould, A.; Gaudi, B. S. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Beaulieu, J.-P. [Institut d' Astrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis Boulevard Arago, 75014 Paris (France); Dominik, M. [School of Physics and Astronomy, SUPA, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Allen, W. [Vintage Lane Observatory, Blenheim (New Zealand); Bos, M. [Molehill Astronomical Observatory, North Shore (New Zealand); Christie, G. W. [Auckland Observatory, P.O. Box 24-180, Auckland (New Zealand); Depoy, D. L. [Department of Physics, Texas A and M University, College Station, TX (United States); Dong, S. [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Drummond, J. [Possum Observatory, Patutahi (New Zealand); Gal-Yam, A. [Benoziyo Center for Astrophysics, the Weizmann Institute (Israel); Hung, L.-W. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Janczak, J. [Department of Physics, Ohio State University, 191 W. Woodruff, Columbus, OH 43210 (United States); Kaspi, S. [School of Physics and Astronomy, Tel-Aviv University, Tel Aviv 69978 (Israel); Collaboration: muFUN Collaboration; MOA Collaboration; OGLE Collaboration; PLANET Collaboration; RoboNet Collaboration; MiNDSTEp Consortium; and others

    2012-02-20

    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 perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a 3{sigma} confidence level for three events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretical prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q {approx} 0.1, making the companion of the lens a strong brown dwarf candidate.

  18. MICROLENSING BINARIES DISCOVERED THROUGH HIGH-MAGNIFICATION CHANNEL

    International Nuclear Information System (INIS)

    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 perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a 3σ confidence level for three events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretical prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q ∼ 0.1, making the companion of the lens a strong brown dwarf candidate.

  19. Particle Dark Matter Candidates

    CERN Document Server

    Scopel, Stefano

    2007-01-01

    I give a short overview on some of the favorite particle Cold Dark Matter candidates today, focusing on those having detectable interactions: the axion, the KK-photon in Universal Extra Dimensions, the heavy photon in Little Higgs and the neutralino in Supersymmetry. The neutralino is still the most popular, and today is available in different flavours: SUGRA, nuSUGRA, sub-GUT, Mirage mediation, NMSSM, effective MSSM, scenarios with CP violation. Some of these scenarios are already at the level of present sensitivities for direct DM searches.

  20. Pulsar Candidates Toward Fermi Unassociated Sources

    CERN Document Server

    Frail, D A; Jagannathan, P; Intema, H T

    2016-01-01

    We report on a search for steep spectrum radio sources within the 95% confidence error ellipses of the Fermi unassociated sources from the Large Array Telescope (LAT). Using existing catalogs and the newly released GMRT all-sky survey at 150 MHz we identify compact radio sources that are bright at MHz frequencies but faint or absent at GHz frequencies. Such steep spectrum radio sources are rare and constitute a sample of pulsar candidates, selected independently of period, dispersion measure, interstellar scattering and orbital parameters. We find point-like, steep spectrum candidates toward 11 Fermi sources. Based on the gamma-ray/radio positional coincidence, the rarity of such radio sources, and the properties of the 3FGL sources themselves, we argue that many of these sources could be pulsars. They may have been missed by previous radio periodicity searches due to interstellar propagation effects or because they lie in an unusually tight binary. If this hypothesis is correct, then renewed gamma-ray and ra...

  1. Binary MEMS gas sensors

    International Nuclear Information System (INIS)

    A novel sensing mechanism for electrostatic MEMS that employs static bifurcation-based sensing and binary detection is demonstrated. It is implemented as an ethanol vapour sensor that exploits the static pull-in bifurcation. Sensor detection of 5 ppm of ethanol vapour in dry nitrogen, equivalent to a detectable mass of 165 pg, is experimentally demonstrated. Sensor robustness to external disturbances is also demonstrated. A closed-form expression for the sensitivity of statically detected electrostatic MEMS sensors is derived. It is shown that the sensitivity of static bifurcation-based binary electrostatic MEMS sensors represents an upper bound on the sensitivity of static detection for given sensor dimensions and material properties. (paper)

  2. Binary Tetrahedral Flavor Symmetry

    CERN Document Server

    Eby, David A

    2013-01-01

    A study of the T' Model and its variants utilizing Binary Tetrahedral Flavor Symmetry. We begin with a description of the historical context and motivations for this theory, together with some conceptual background for added clarity, and an account of our theory's inception in previous works. Our model endeavors to bridge two categories of particles, leptons and quarks, a unification made possible by the inclusion of additional Higgs particles, shared between the two fermion sectors and creating a single coherent system. This is achieved through the use of the Binary Tetrahedral symmetry group and an investigation of the Tribimaximal symmetry evidenced by neutrinos. Our work details perturbations and extensions of this T' Model as we apply our framework to neutrino mixing, quark mixing, unification, and dark matter. Where possible, we evaluate model predictions against experimental results and find excellent matching with the atmospheric and reactor neutrino mixing angles, an accurate prediction of the Cabibb...

  3. Compressing Binary Decision Diagrams

    CERN Document Server

    Hansen, Esben Rune; Tiedemann, Peter

    2008-01-01

    The paper introduces a new technique for compressing Binary Decision Diagrams in those cases where random access is not required. Using this technique, compression and decompression can be done in linear time in the size of the BDD and compression will in many cases reduce the size of the BDD to 1-2 bits per node. Empirical results for our compression technique are presented, including comparisons with previously introduced techniques, showing that the new technique dominate on all tested instances.

  4. Astrometry and high-speed photometry of an optical candidate for PSR 1913+16

    International Nuclear Information System (INIS)

    A deep IIIaF plate has been obtained at the prime focus of the AAT which shows the candidate star described by previous workers near the timing position of the binary pulsar 1913+16. Our astrometry shows that this star does not coincide with the timing position. High-speed photometry of the candidate shows no evidence for pulsations down to a time-averaged R magnitude of 26.5. (author)

  5. Kepler Eclipsing Binary Stars. VI. Identification of Eclipsing Binaries in the K2 Campaign 0 Data-set

    CERN Document Server

    LaCourse, Daryll M; Jacobs, Thomas L; Winarski, Troy; Boyajian, Tabetha S; Rappaport, Saul A; Sanchis-Ojeda, Roberto; Conroy, Kyle E; Nelson, Lorne; Barclay, Tom; Fischer, Debra A; Schmitt, Joseph R; Wang, Ji; Prša, Andrej; Stassun, Keivan G; Pepper, Joshua; Coughlin, Jeffrey L; Shporer, Avi

    2015-01-01

    The original Kepler mission observed and characterized over 2400 eclipsing binaries in addition to its prolific exoplanet detections. Despite the mechanical malfunction and subsequent non-recovery of two reaction wheels used to stabilize the instrument, the Kepler satellite continues collecting data in its repurposed K2 mission surveying a series of fields along the ecliptic plane. Here we present an analysis of the first full baseline K2 data release: the Campaign 0 data-set. In the 7761 light curves, we have identified a total of 207 eclipsing binaries. Of these, 97 are new discoveries that were not previously identified. Our pixel level analysis of these objects has also resulted in identification of several false positive eclipsing binaries and the serendipitous discovery of three short period exoplanet candidates. We provide catalog cross-matched source identifications, orbital periods, morphologies and ephemerides for these eclipsing systems. We also describe the incorporation of the sample into the Kep...

  6. Binary-Signal Recovery

    Science.gov (United States)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  7. 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.

  8. Hunting for brown dwarf binaries and testing atmospheric models with X-Shooter

    Science.gov (United States)

    Manjavacas, E.; Goldman, B.; Alcalá, J. M.; Zapatero-Osorio, M. R.; Béjar, V. J. S.; Homeier, D.; Bonnefoy, M.; Smart, R. L.; Henning, T.; Allard, F.

    2016-01-01

    The determination of the brown dwarf binary fraction may contribute to the understanding of the substellar formation mechanisms. Unresolved brown dwarf binaries may be revealed through their peculiar spectra or the discrepancy between optical and near-infrared spectral-type classification. We obtained medium-resolution spectra of 22 brown dwarfs with these characteristics using the X-Shooter spectrograph at the Very Large Telescope. We aimed to identify brown dwarf binary candidates, and to test if the BT-Settl 2014 atmospheric models reproduce their observed spectra. To find binaries spanning the L-T boundary, we used spectral indices and compared the spectra of the selected candidates to single spectra and synthetic binary spectra. We used synthetic binary spectra with components of same spectral type to determine as well the sensitivity of the method to this class of binaries. We identified three candidates to be combination of L plus T brown dwarfs. We are not able to identify binaries with components of similar spectral type. In our sample, we measured minimum binary fraction of 9.1^{+9.9}_{-3.0} per cent. From the best fit of the BT-Settl models 2014 to the observed spectra, we derived the atmospheric parameters for the single objects. The BT-Settl models were able to reproduce the majority of the spectral energy distributions from our objects, and the variation of the equivalent width of the Rb I (794.8 nm) and Cs I (852.0 nm) lines with the spectral type. None the less, these models did not reproduce the evolution of the equivalent widths of the Na I (818.3 and 819.5 nm) and K I (1253 nm) lines with the spectral type.

  9. PLANET HUNTERS: NEW KEPLER PLANET CANDIDATES FROM ANALYSIS OF QUARTER 2

    International Nuclear Information System (INIS)

    We present new planet candidates identified in NASA Kepler Quarter 2 public release data by volunteers engaged in the Planet Hunters citizen science project. The two candidates presented here survive checks for false positives, including examination of the pixel offset to constrain the possibility of a background eclipsing binary. The orbital periods of the planet candidates are 97.46 days (KIC 4552729) and 284.03 (KIC 10005758) days and the modeled planet radii are 5.3 and 3.8 R⊕. The latter star has an additional known planet candidate with a radius of 5.05 R⊕ and a period of 134.49 days, which was detected by the Kepler pipeline. The discovery of these candidates illustrates the value of massively distributed volunteer review of the Kepler database to recover candidates which were otherwise uncataloged.

  10. PLANET HUNTERS: NEW KEPLER PLANET CANDIDATES FROM ANALYSIS OF QUARTER 2

    Energy Technology Data Exchange (ETDEWEB)

    Lintott, Chris J. [Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Schwamb, Megan E.; Schwainski, Kevin, E-mail: cjl@astro.ox.ac.uk [Department of Physics, Yale University, P.O. Box 208121, New Haven, CT 06520 (United States); and others

    2013-06-15

    We present new planet candidates identified in NASA Kepler Quarter 2 public release data by volunteers engaged in the Planet Hunters citizen science project. The two candidates presented here survive checks for false positives, including examination of the pixel offset to constrain the possibility of a background eclipsing binary. The orbital periods of the planet candidates are 97.46 days (KIC 4552729) and 284.03 (KIC 10005758) days and the modeled planet radii are 5.3 and 3.8 R{sub Circled-Plus }. The latter star has an additional known planet candidate with a radius of 5.05 R{sub Circled-Plus} and a period of 134.49 days, which was detected by the Kepler pipeline. The discovery of these candidates illustrates the value of massively distributed volunteer review of the Kepler database to recover candidates which were otherwise uncataloged.

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

    International Nuclear Information System (INIS)

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

  12. Non-thermal emission from high-energy binaries through interferometric radio observations

    CERN Document Server

    Marcote, B

    2016-01-01

    High-mass binary systems involve extreme environments that produce non-thermal emission from radio to gamma rays. Only three types of these systems are known to emit persistent gamma-ray emission: colliding-wind binaries, high-mass X-ray binaries and gamma-ray binaries. This thesis is focused on the radio emission of high-mass binary systems through interferometric observations, and we have explored several of these sources with low- and high-frequency radio observations, and very high-resolution VLBI ones. We have studied two gamma-ray binaries, LS 5039 and LS I +61 303, at low frequencies. We have obtained their light-curves and spectra, and we have determined the physical properties of their radio emitting regions. We have also studied the gamma-ray binary HESS J0632+057 through VLBI observations. A new colliding wind binary, HD 93129A, has been discovered through VLBI and optical observations. Finally, we have conducted radio observations of two sources that were candidates to be gamma-ray binaries.

  13. Biclustering Sparse Binary Genomic Data

    OpenAIRE

    Van Uitert, M.; Meuleman, W.; Wessels, L. F. A.

    2008-01-01

    Genomic datasets often consist of large, binary, sparse data matrices. In such a dataset, one is often interested in finding contiguous blocks that (mostly) contain ones. This is a biclustering problem, and while many algorithms have been proposed to deal with gene expression data, only two algorithms have been proposed that specifically deal with binary matrices. None of the gene expression biclustering algorithms can handle the large number of zeros in sparse binary matrices. The two propos...

  14. Parameters of 20 newly detected eclipsing binaries from the Kepler database

    CERN Document Server

    Dimitrov, Dinko P; Radeva, Veselka S

    2012-01-01

    The paper presents a sample of newly detected eclipsing binaries from the public Kepler data. Orbits and fundamental parameters of 20 unknown eclipsing binaries were determined by modeling of their photometric data. Most of them are well-detached, high-eccentric binaries. We established that the target KID8552719 satisfied all widespread criteria for a planetary candidate. Fitting its light curve we obtained radius R_p=0.9 R_Nept, distance to the host star a = 42.58 Rsun = 0.198 AU and equilibrium temperatute T_p= 489 K. These values imply a Neptune-size object out of the habitable zone of the host star.

  15. Evolution of Close Binary Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  16. Report IAU Comm. 42, Close Binary Stars

    OpenAIRE

    Ribas, Ignasi; Scarfe, Colin D.; Torres, Guillermo; Rucinski, Slavek M.; Sion, Edward M.; Richards, Mercedes T.; Niarchos, Panayiotis; Olah, Katalin

    2008-01-01

    Brief summaries are given about (1) close binary research from the perspective of the Bibliography of Close Binaries, (2) low-mass binaries and model discrepancies, (3) W UMa-type binaries, (4) cataclysmic variables, (5) Algol binaries, (6) the oEA stars, (7) effects of binarity on stellar activity.

  17. Low autocorrelation binary sequences

    Science.gov (United States)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  18. Magnetic binary nanofillers

    International Nuclear Information System (INIS)

    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. Computing on Binary Strings

    CERN Document Server

    Bu, Tian-Ming; Zhang, Peng

    2011-01-01

    Many problems in Computer Science can be abstracted to the following question: given a set of objects and rules respectively, which new objects can be produced? In the paper, we consider a succinct version of the question: given a set of binary strings and several operations like conjunction and disjunction, which new binary strings can be generated? Although it is a fundamental problem, to the best of our knowledge, the problem hasn't been studied yet. In this paper, an O(m^2n) algorithm is presented to determine whether a string s is representable by a set W, where n is the number of strings in W and each string has the same length m. However, looking for the minimum subset from a set to represent a given string is shown to be NP-hard. In addition, we prove that counting the number of strings representable is #P-complete. But if the operator negation can be used, the number is some power of 2. This di?erence maybe help us understand the problem more profoundly.

  20. Planet Hunters: New Kepler planet candidates from analysis of quarter 2

    OpenAIRE

    Lintott, Chris J.; Schwamb, Megan E.; Barclay, Thomas; Sharzer, Charlie; Fischer, Debra A; Brewer, John; Giguere, Matthew; Lynn, Stuart; Parrish, Michael; Batalha, Natalie; Bryson, Steve; Jenkins, Jon; Ragozzine, Darin; Rowe, Jason F.; Schwainski, Kevin

    2012-01-01

    We present new planet candidates identified in NASA Kepler quarter two public release data by volunteers engaged in the Planet Hunters citizen science project. The two candidates presented here survive checks for false-positives, including examination of the pixel offset to constrain the possibility of a background eclipsing binary. The orbital periods of the planet candidates are 97.46 days (KIC 4552729) and 284.03 (KIC 10005758) days and the modeled planet radii are 5.3 and 3.8 R_Earth. The...

  1. Generic Phase Diagram of Binary Superlattices

    Science.gov (United States)

    Tkachenko, Alexei

    Emergence of a large variety of self-assembled superlattices is a dramatic recent trend in the fields of nanoparticle and colloidal sciences. Motivated by this development, we propose a model that combines simplicity with a remarkably rich phase behavior, applicable to a wide range of such self-assembled systems. Those include nanoparticle and colloidal assemblies driven by DNA-mediated interactions, electrostatics, and possibly, by controlled drying. In our model, a binary system of Large and Small hard sphere (L and S)interact via selective short-range (''sticky'') attraction. In its simplest version, this Binary Sticky Sphere model features attraction only between 'S' and 'L' particles, respectively. We demonstrate that in the limit when this attraction is sufficiently strong compared to kT, the problem becomes purely geometrical: the thermodynamically preferred state should maximize the number of S-L contacts. A general procedure for constructing the phase diagram as a function of system composition f, and particle size ratio r, is outlined. In this way, the global phase behavior can be calculated very efficiently, for a given set of plausible candidate phases. Furthermore, the geometric nature of the problem enables us to generate those candidate phases through a well defined and intuitive construction. We calculate the phase diagrams both for 2D and 3D systems, and compare the results with existing experiments. Most of the 3D superlattices observed to date are featured in our phase diagram, while several more are yet to be discovered. The research was carried out at the CFN, DOE Office of Science Facility, at BNL, under Contract No. DE-SC0012704.

  2. Observations of accretion discs in interacting binaries

    Science.gov (United States)

    Honey, William Bruce

    Cataclysmic and X-ray binaries (CV and LMXB) are considered, and new observations of both types of source are considered. Chapter 1 gives an introduction to the subject and presents a study of the evolution and period relationships of these objects. Chapter 2 studies the superoutburst of a system. The observational data presented in the Chapter are used to place constraints on the geometry of the system, and also upon the theoretical models examined; only eccentric disc models are found to be acceptable. A tidally dominated eccentric accretion disc is considered, and good agreement between the observations and a tidally distorted disc simulation is achieved. In Chapter 3, a search for the superhump phenomenon is conducted. No such superhump behavior was found. These observations support the ideas first raised in Chapter 2 of the importance of tidal behavior in dwarf novae. Chapter 4 reviews observations of black hole candidates, and lists the generally expected 'fingerprint' thought to be associated with black holes in binary systems. Chapter 5 reports on observations of the LMXB GX339-4 and the discovery of the period for the system. Constraints on the system parameters are given and a model is presented that is compatible with the observations. Chapter 6 reviews the work done and considers other important observational evidence that is to be found in the literature and is pertinent to the work in this thesis.

  3. Electoral Systems and Candidate Selection

    NARCIS (Netherlands)

    Hazan, Reuven Y.; Voerman, Gerrit

    2006-01-01

    Electoral systems at the national level and candidate selection methods at the party level are connected, maybe not causally but they do influence each other. More precisely, the electoral system constrains and conditions the parties' menu of choices concerning candidate selection. Moreover, in ligh

  4. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew J.

    2006-02-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing 10^4 - 10^7 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 the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution 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.

  5. 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.

  6. PERIODIC COMPLEMENTARY BINARY SEQUENCE PAIRS

    Institute of Scientific and Technical Information of China (English)

    XuChengqian; ZhaoXiaoqun

    2002-01-01

    A new set of binary sequences-Periodic Complementary Binary Sequence Pair (PCSP)is proposed .A new class of block design-Difference Family Pair (DFP)is also proposed .The relationship between PCSP and DFP,the properties and exising conditions of PCSP and the recursive constructions for PCSP are given.

  7. PERIODIC COMPLEMENTARY BINARY SEQUENCE PAIRS

    Institute of Scientific and Technical Information of China (English)

    Xu Chengqian; Zhao Xiaoqun

    2002-01-01

    A new set of binary sequences-Periodic Complementary Binary Sequence Pair (PCSP) is proposed. A new class of block design-Difference Family Pair (DFP) is also proposed.The relationship between PCSP and DFP, the properties and existing conditions of PCSP and the recursive constructions for PCSP are given.

  8. SLoWPoKES-II: 100,000 Wide Binaries Identified in SDSS without Proper Motions

    Science.gov (United States)

    Dhital, Saurav; West, Andrew A.; Stassun, Keivan G.; Schluns, Kyle J.; Massey, Angela P.

    2015-08-01

    We present the Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES)-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey (SDSS) by matching photometric distances. The candidate pairs are vetted by comparing the stellar information. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without the need for proper motions. Here, 105,537 visual binaries with angular separations of ˜1-20″ were identified, each with a probability of chance alignment of ≤5%. This is the largest catalog of bona fide wide binaries to date, and it contains a diversity of systems—in mass, mass ratios, binary separations, metallicity, and evolutionary states—that should facilitate follow-up studies to characterize the properties of M dwarfs and white dwarfs. There is a subtle but definitive suggestion of multiple populations in the physical separation distribution, supporting earlier findings. We suggest that wide binaries are composed of multiple populations, most likely representing different formation modes. There are 141 M7 or later wide binary candidates, representing a seven-fold increase over the number currently known. These binaries are too wide to have been formed via the ejection mechanism. Finally, we found that 6% of spectroscopically confirmed M dwarfs are not included in the SDSS STAR catalog; they are misclassified as extended sources due to the presence of a nearby or partially resolved companion. The SLoWPoKES-II catalog is publicly available to the entire community on the World Wide Web via the Filtergraph data visualization portal.

  9. Pairing mechanisms for binary stars

    CERN Document Server

    Kouwenhoven, M B N; Goodwin, S P; Zwart, S F Portegies; Kaper, L; 10.1002/asna.200811061

    2008-01-01

    Knowledge of the binary population in stellar groupings provides important information about the outcome of the star forming process in different environments. Binarity is also a key ingredient in stellar population studies and is a prerequisite to calibrate the binary evolution channels. In these proceedings we present an overview of several commonly used methods to pair individual stars into binary systems, which we refer to as the pairing function. Many pairing functions are frequently used by observers and computational astronomers, either for the mathematical convenience, or because they roughly describe the expected outcome of the star forming process. We discuss the consequences of each pairing function for the interpretation of observations and numerical simulations. The binary fraction and mass ratio distribution generally depend strongly on the selection of the range in primary spectral type in a sample. These quantities, when derived from a binary survey with a mass-limited sample of target stars, ...

  10. 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...

  11. A spectroscopic and proper motion search of SDSS: Red subdwarfs in binary systems

    CERN Document Server

    Zhang, Z H; Burningham, B; Jones, H R A; Galvez-Ortiz, M C; Catalan, S; Smart, R L; Lepine, S; Clarke, J R A; Pavlenko, Ya V; Murray, D N; Kuznetsov, M K; Day-Jones, A C; Gomes, J; Marocco, F; Sipocz, B

    2013-01-01

    Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with SDSS spectroscopy. We present here discoveries from this search, as well as highlighting several additional objects of interest. We find thirty red subdwarfs in wide binary systems including: two with spectral type of esdM5.5, six companions to white dwarfs and three carbon enhanced red subdwarfs with normal red subdwarf companions. Fifteen red subdwarfs in our sample are partially resolved close binary systems. With this binary sample, we estimate the low limit of the red subdwarf binary fraction of ~ 10%. We find that the binary fraction goes down with decreasing masses and metallicities of red subdwarfs. A spectroscopic esdK7 subdwarf + white dwarf binary candidate is also reported. Thirty new M subdwarfs have spectral type of >M6 in our sample. We also derive relationships between spectral types and absolute magni...

  12. Towards Physarum Binary Adders

    CERN Document Server

    Jones, Jeff; 10.1016/j.biosystems.2010.04.005

    2010-01-01

    Plasmodium of \\emph{Physarum polycephalum} is a single cell visible by unaided eye. The plasmodium's foraging behaviour is interpreted in terms of computation. Input data is a configuration of nutrients, result of computation is a network of plasmodium's cytoplasmic tubes spanning sources of nutrients. Tsuda et al (2004) experimentally demonstrated that basic logical gates can be implemented in foraging behaviour of the plasmodium. We simplify the original designs of the gates and show --- in computer models --- that the plasmodium is capable for computation of two-input two-output gate $ \\to $ and three-input two-output $ \\to $. We assemble the gates in a binary one-bit adder and demonstrate validity of the design using computer simulation.

  13. Eccentric Binary Millisecond Pulsars

    CERN Document Server

    Freire, Paulo C C

    2009-01-01

    In this paper we review the recent discovery of several millisecond pulsars (MSPs) in eccentric binary systems. Timing these MSPs we were able to estimate (and in one case precisely measure) their masses. These results suggest that, as a class, MSPs have a much wider range of masses (1.3 to > 2 solar masses) than the normal and mildly recycled pulsars found in double neutron star (DNS) systems (1.25 < Mp < 1.44 solar masses). This is very likely to be due to the prolonged accretion episode that is thought to be required to form a MSP. The likely existence of massive MSPs makes them a powerful probe for understanding the behavior of matter at densities larger than that of the atomic nucleus; in particular, the precise measurement of the mass of PSR J1903+0327 ($1.67 +/- 0.01 solar masses) excludes several "soft" equations of state for dense matter.

  14. Binaries and distances

    Science.gov (United States)

    Pourbaix, D.; Arenou, F.; Halbwachs, J.-L.; Siopis, C.

    2013-02-01

    Gaia's five-year observation baseline might naively lead to the expectation that it will be possible to fit the parallax of any sufficiently nearby object with the default five-parameter model (position at a reference epoch, parallax and proper motion). However, simulated Gaia observations of a `model Universe' composed of nearly 107 objects, 50% of which turn out to be multiple stars, show that the single-star hypothesis can severely affect parallax estimation and that more sophisticated models must be adopted. In principle, screening these spurious single-star solutions is rather straightforward, for example by evaluating the quality of the fits. However, the simulated Gaia observations also reveal that some seemingly acceptable single-star solutions can nonetheless lead to erroneous distances. These solutions turn out to be binaries with an orbital period close to one year. Without auxiliary (e.g., spectroscopic) data, they will remain unnoticed.

  15. Evidence of a Massive Black Hole Companion in the Massive Eclipsing Binary V Puppis

    CERN Document Server

    Qian, S -B; Fernandez-Lajus, E

    2008-01-01

    Up to now, most stellar-mass black holes were discovered in X-ray emitting binaries, in which the black holes are formed through a common-envelope evolu tion. Here we give evidence for the presence of a massive black hole candidate as a tertiary companion in the massive eclipsing binary V Puppis. We found that the orbital period of this short-period binary (P=1.45 days) shows a periodic variation while it undergoes a long-term increase. The cyclic period oscillation can be interpreted by the light-travel time effect via the presence of a third body with a mass no less than 10.4 solar mass. However, no spectral lines of the third body were discovered indicating that it is a massive black hole candidate. The black hole candidate may correspond to the weak X-ray source close to V Puppis discovered by Uhuru, Copernicus, and ROSAT satellites produced by accreting materials from the massive binary via stellar wind. The circumstellar matter with many heavy elements around this binary may be formed by the supernova e...

  16. DANCING IN THE DARK: NEW BROWN DWARF BINARIES FROM KERNEL PHASE INTERFEROMETRY

    International Nuclear Information System (INIS)

    This paper revisits a sample of ultracool dwarfs in the solar neighborhood previously observed with the Hubble Space Telescope's NICMOS NIC1 instrument. We have applied a novel high angular resolution data analysis technique based on the extraction and fitting of kernel phases to archival data. This was found to deliver a dramatic improvement over earlier analysis methods, permitting a search for companions down to projected separations of ∼1 AU on NIC1 snapshot images. We reveal five new close binary candidates and present revised astrometry on previously known binaries, all of which were recovered with the technique. The new candidate binaries have sufficiently close separation to determine dynamical masses in a short-term observing campaign. We also present four marginal detections of objects which may be very close binaries or high-contrast companions. Including only confident detections within 19 pc, we report a binary fraction of at least ϵb = 17.2−3.7+5.7%. The results reported here provide new insights into the population of nearby ultracool binaries, while also offering an incisive case study of the benefits conferred by the kernel phase approach in the recovery of companions within a few resolution elements of the point-spread function core.

  17. DANCING IN THE DARK: NEW BROWN DWARF BINARIES FROM KERNEL PHASE INTERFEROMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Pope, Benjamin; Tuthill, Peter [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2226 (Australia); Martinache, Frantz, E-mail: bjsp@physics.usyd.edu.au, E-mail: p.tuthill@physics.usyd.edu.au, E-mail: frantz@naoj.org [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI 96720 (United States)

    2013-04-20

    This paper revisits a sample of ultracool dwarfs in the solar neighborhood previously observed with the Hubble Space Telescope's NICMOS NIC1 instrument. We have applied a novel high angular resolution data analysis technique based on the extraction and fitting of kernel phases to archival data. This was found to deliver a dramatic improvement over earlier analysis methods, permitting a search for companions down to projected separations of {approx}1 AU on NIC1 snapshot images. We reveal five new close binary candidates and present revised astrometry on previously known binaries, all of which were recovered with the technique. The new candidate binaries have sufficiently close separation to determine dynamical masses in a short-term observing campaign. We also present four marginal detections of objects which may be very close binaries or high-contrast companions. Including only confident detections within 19 pc, we report a binary fraction of at least #Greek Lunate Epsilon Symbol#{sub b} = 17.2{sub -3.7}{sup +5.7}%. The results reported here provide new insights into the population of nearby ultracool binaries, while also offering an incisive case study of the benefits conferred by the kernel phase approach in the recovery of companions within a few resolution elements of the point-spread function core.

  18. Single Transit Candidates from K2: Detection and Period Estimation

    CERN Document Server

    Osborn, H P; Brown, D J A; McCormac, J; Doyle, A P; Louden, T M; Kirk, J; Spake, J J; Lam, K W F; Walker, S R; Faedi, F; Pollacco, D L

    2015-01-01

    Photometric surveys such as Kepler have the precision to identify exoplanet and eclipsing binary candidates from only a single transit. K2, with its 75d campaign duration, is ideally suited to detect significant numbers of single-eclipsing objects. Here we develop a Bayesian transit-fitting tool ("Namaste: An Mcmc Analysis of Single Transit Exoplanets") to extract orbital information from single transit events. We achieve favourable results testing this technique on known Kepler planets, and apply the technique to 7 candidates identified from a targeted search of K2 campaigns 1, 2 and 3. We find EPIC203311200 to host an excellent exoplanet candidate with a period, assuming zero eccentricity, of $540 ^{+410}_{-230}$ days and a radius of $0.51 \\pm 0.05 R_{Jup}$. We also find six further transit candidates for which more follow-up is required to determine a planetary origin. Such a technique could be used in the future with TESS, PLATO and ground-based photometric surveys such as NGTS, potentially allowing the d...

  19. A Systematic Search for Exoplanet Candidates in K2 Data

    Science.gov (United States)

    Kahre, Tarryn; Karnes, Katherine L.; Caldwell, Douglas A.; Smith, Jeffrey C.

    2016-01-01

    We present a catalog of 41 promising exoplanet candidates in 33 stellar systems from the K2 Campaign 3 data. The K2 Mission was developed upon the mechanical failure of the second of four reaction wheels, as the Kepler Spacecraft could not continue the original Kepler Mission. The Kepler Mission was a 4-year mission designed to determine the prevalence of exoplanets in our galaxy, and the configuration and diversity of those planetary systems discovered. The K2 Mission has a similar goal, though the spacecraft now points at fields along the ecliptic in ~75 day campaigns (Howell et al. 2014). Although the light curves in K2 data are noisier and have significant motion-induced systematics, it has been shown that there is success in finding exoplanets and exoplanet candidates (Foreman-Mackey et al. 2015; Montet et al. 2015). Utilizing the Transiting Planet Search and Data Validation from the Kepler Processing Pipeline, we systematically search K2 Campaign 3 for potential exoplanet candidates. Setting a 7.1s maximum folded statistic threshold minimum for a minimum of three transit events, we define our initial candidate list. Our list is further narrowed by the results from Data Validation, as it allows us to statistically identify false positives, such as eclipsing binaries or uncorrected roll-drift, in our sample. We further draw parallels between our results and other transit-searching pipeline results published for Campaign 3.

  20. Single transit candidates from K2: detection and period estimation

    Science.gov (United States)

    Osborn, H. P.; Armstrong, D. J.; Brown, D. J. A.; McCormac, J.; Doyle, A. P.; Louden, T. M.; Kirk, J.; Spake, J. J.; Lam, K. W. F.; Walker, S. R.; Faedi, F.; Pollacco, D. L.

    2016-04-01

    Photometric surveys such as Kepler have the precision to identify exoplanet and eclipsing binary candidates from only a single transit. K2, with its 75 d campaign duration, is ideally suited to detect significant numbers of single-eclipsing objects. Here we develop a Bayesian transit-fitting tool (`Namaste: An Mcmc Analysis of Single Transit Exoplanets') to extract orbital information from single transit events. We achieve favourable results testing this technique on known Kepler planets, and apply the technique to seven candidates identified from a targeted search of K2 campaigns 1, 2 and 3. We find EPIC203311200 to host an excellent exoplanet candidate with a period, assuming zero eccentricity, of 540 ^{+410}_{-230} d and a radius of 0.51 ± 0.05RJup. We also find six further transit candidates for which more follow-up is required to determine a planetary origin. Such a technique could be used in the future with TESS, PLATO and ground-based photometric surveys such as NGTS, potentially allowing the detection of planets in reach of confirmation by Gaia.

  1. Exploring Dual and Binary AGN via Radio Emission

    Science.gov (United States)

    Burke Spolaor, Sarah; Lazio, J.

    2012-05-01

    Dual and binary supermassive black holes (SMBHs) are thought to form as a direct result of a major galaxy merger. The discovery of late-stage SMBH pairs could critically inform upcoming gravitational wave science and cosmological formation models, and could provide fascinating studies of post-merger dynamics and merger-induced SMBH growth. However, it has been notoriously difficult to identify clear electromagnetic markers for dual and binary SMBHs in late-stage merger systems. Accordingly, few definitive discoveries of paired SMBHs have yet been made, with only a handful of known systems at projected separations below 1kpc. We will review the unique contributions that radio imaging observations can make to this field: particularly in the search for new systems, the confirmation of candidate small-orbit binary systems, and the potential for multi-messenger gravitational wave science when combined with pulsar timing methods. We will also provide an update on recent radio searches for binary AGN. We acknowledge that a portion of research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  2. Modeling AGN outbursts from supermassive black hole binaries

    Directory of Open Access Journals (Sweden)

    Tanaka T.

    2012-12-01

    Full Text Available When galaxies merge to assemble more massive galaxies, their nuclear supermassive black holes (SMBHs should form bound binaries. As these interact with their stellar and gaseous environments, they will become increasingly compact, culminating in inspiral and coalescence through the emission of gravitational radiation. Because galaxy mergers and interactions are also thought to fuel star formation and nuclear black hole activity, it is plausible that such binaries would lie in gas-rich environments and power active galactic nuclei (AGN. The primary difference is that these binaries have gravitational potentials that vary – through their orbital motion as well as their orbital evolution – on humanly tractable timescales, and are thus excellent candidates to give rise to coherent AGN variability in the form of outbursts and recurrent transients. Although such electromagnetic signatures would be ideally observed concomitantly with the binary’s gravitational-wave signatures, they are also likely to be discovered serendipitously in wide-field, high-cadence surveys; some may even be confused for stellar tidal disruption events. I discuss several types of possible “smoking gun” AGN signatures caused by the peculiar geometry predicted for accretion disks around SMBH binaries.

  3. Binary black hole spectroscopy

    International Nuclear Information System (INIS)

    We study parameter estimation with post-Newtonian (PN) gravitational waveforms for the quasi-circular, adiabatic inspiral of spinning binary compact objects. In particular, the performance of amplitude-corrected waveforms is compared with that of the more commonly used restricted waveforms, in Advanced LIGO and EGO. With restricted waveforms, the properties of the source can only be extracted from the phasing. In the case of amplitude-corrected waveforms, the spectrum encodes a wealth of additional information, which leads to dramatic improvements in parameter estimation. At distances of ∼100 Mpc, the full PN waveforms allow for high-accuracy parameter extraction for total mass up to several hundred solar masses, while with the restricted ones the errors are steep functions of mass, and accurate parameter estimation is only possible for relatively light stellar mass binaries. At the low-mass end, the inclusion of amplitude corrections reduces the error on the time of coalescence by an order of magnitude in Advanced LIGO and a factor of 5 in EGO compared to the restricted waveforms; at higher masses these differences are much larger. The individual component masses, which are very poorly determined with restricted waveforms, become measurable with high accuracy if amplitude-corrected waveforms are used, with errors as low as a few per cent in Advanced LIGO and a few tenths of a per cent in EGO. The usual spin-orbit parameter β is also poorly determined with restricted waveforms (except for low-mass systems in EGO), but the full waveforms give errors that are small compared to the largest possible value consistent with the Kerr bound. This suggests a way of finding out if one or both of the component objects violate this bound. On the other hand, we find that the spin-spin parameter σ remains poorly determined even when the full waveform is used. Generally, all errors have but a weak dependence on the magnitudes and orientations of the spins. We also briefly

  4. Strong Lensing by Binary Galaxies

    CERN Document Server

    Shin, E M

    2008-01-01

    We study the problem of gravitational lensing by binary galaxies, idealized as two isothermal spheres. In a wide binary, each galaxy possesses individual tangential, nearly astroidal, caustics and roundish radial caustics. As the separation of the binary is made smaller, the caustics undergo a sequence of metamorphoses. The first metamorphosis occurs when the tangential caustics merge to form a single six-cusped caustic, lying interior to the radial caustics. At still smaller separations, the six-cusped caustic undergoes the second metamorphosis and splits into a four-cusped caustic and two three-cusped caustics, which shrink to zero size (an elliptic umbilic catastrophe) before they enlarge again and move away from the origin perpendicular to the binary axis. Finally, a third metamorphosis occurs as the three-cusp caustics join the radial caustics, leaving an inner distorted astroid caustic enclosed by two outer caustics. The maximum number of images possible is 7. Classifying the multiple imaging according ...

  5. Magnetic braking in ultracompact binaries

    CERN Document Server

    Farmer, Alison

    2010-01-01

    Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether magnetically coupled winds could in fact lead to substantial additional angular momentum losses. We remark that the scaling relations often invoked for the relative importance of gravitational and magnetic braking do not apply, and instead use simple non-empirical expressions for the braking rates. In order to remove significant angular momentum, the wind must be tied to field lines anchored in one of the binary's component stars; uncertainties remain as to the driving mechanism for such a wind. In the case of white dwarf accretors, we find that magnetic braking can potentially remove angular momentum on comparable or even shorter timescales than gravitational waves over a large range in orbital period. We present such a solution for the 17-minute binary AM CVn itself which a...

  6. Discs in misaligned binary systems

    CERN Document Server

    Rawiraswattana, Krisada; Goodwin, Simon P

    2016-01-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-...

  7. Cryptography with DNA binary strands.

    Science.gov (United States)

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'. PMID:10963862

  8. AN IMPROVED DESIGN OF REVERSIBLE BINARY TO BINARY CODED DECIMAL CONVERTER FOR BINARY CODED DECIMAL MULTIPLICATION

    Directory of Open Access Journals (Sweden)

    Praveena Murugesan

    2014-01-01

    Full Text Available Reversible logic gates under ideal conditions produce zero power dissipation. This factor highlights the usage of these gates in optical computing, low power CMOS design, quantum optics and quantum computing. The growth of decimal arithmetic in various applications as stressed the need to propose the study on reversible binary to BCD converter which plays a greater role in decimal multiplication for providing faster results. The different parameters such as gate count,garbage output and constant input are more optimized in the proposed fixed bit binary to binary coded decimal converter than the existing design.

  9. Transient Black Hole Binaries

    CERN Document Server

    Belloni, T M

    2016-01-01

    The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...

  10. Binary nucleation beyond capillarity approximation

    OpenAIRE

    Kalikmanov, V.I.

    2010-01-01

    Large discrepancies between binary classical nucleation theory (BCNT) and experiments result from adsorption effects and inability of BCNT, based on the phenomenological capillarity approximation, to treat small clusters. We propose a model aimed at eliminating both of these deficiencies. Adsorption is taken into account within Gibbsian approximation. Binary clusters are treated by means of statistical-mechanical considerations: tracing out the molecular degrees of freedom of the more volatil...

  11. Clostridium difficile binary toxin CDT

    OpenAIRE

    Gerding, Dale N.; Johnson, Stuart; Rupnik, Maja; Aktories, Klaus

    2013-01-01

    Binary toxin (CDT) is frequently observed in Clostridium difficile strains associated with increased severity of C. difficile infection (CDI). CDT belongs to the family of binary ADP-ribosylating toxins consisting of two separate toxin components: CDTa, the enzymatic ADP-ribosyltransferase which modifies actin, and CDTb which binds to host cells and translocates CDTa into the cytosol. CDTb is activated by serine proteases and binds to lipolysis stimulated lipoprotein receptor. ADP-ribosylatio...

  12. Coalescence of Binary Neutron Stars

    OpenAIRE

    Oohara, Ken-ichi; Namamura, Takashi

    1996-01-01

    The most important sources for laser-interferometric gravitational-wave detectors like LIGO or VIRGO are catastrophic events such as coalescence of a neutron-star binary. The final phase, or the last three milliseconds, of coalescence is considered. We describe results of numerical simulations of coalescing binary neutron stars using Newtonian and post-Newtonian hydrodynamics code and then discuss recent development of our 3D GR code.

  13. Orbital period changes and the higher-order multiplicity fraction amongst SuperWASP eclipsing binaries

    CERN Document Server

    Lohr, M E; Payne, S G; West, R G; Wheatley, P J

    2015-01-01

    Orbital period changes of binary stars may be caused by the presence of a third massive body in the system. Here we have searched the archive of the Wide Angle Search for Planets (SuperWASP) project for evidence of period variations in 13927 eclipsing binary candidates. Sinusoidal period changes, strongly suggestive of third bodies, were detected in 2% of cases; however, linear period changes were observed in a further 22% of systems. We argue on distributional grounds that the majority of these apparently linear changes are likely to reflect longer-term sinusoidal period variations caused by third bodies, and thus estimate a higher-order multiplicity fraction of 24% for SuperWASP binaries, in good agreement with other recent figures for the fraction of triple systems amongst binary stars in general.

  14. Multivariate Classification with Random Forests for Gravitational Wave Searches of Black Hole Binary Coalescence

    CERN Document Server

    Baker, Paul T; Hodge, Kari A; Talukder, Dipongkar; Capano, Collin; Cornish, Neil J

    2014-01-01

    Searches for gravitational waves produced by coalescing black hole binaries with total masses $\\gtrsim25\\,$M$_\\odot$ use matched filtering with templates of short duration. Non-Gaussian noise bursts in gravitational wave detector data can mimic short signals and limit the sensitivity of these searches. Previous searches have relied on empirically designed statistics incorporating signal-to-noise ratio and signal-based vetoes to separate gravitational wave candidates from noise candidates. We report on sensitivity improvements achieved using a multivariate candidate ranking statistic derived from a supervised machine learning algorithm. We apply the random forest of bagged decision trees technique to two separate searches in the high mass $\\left( \\gtrsim25\\,\\mathrm{M}_\\odot \\right)$ parameter space. For a search which is sensitive to gravitational waves from the inspiral, merger, and ringdown (IMR) of binary black holes with total mass between $25\\,$M$_\\odot$ and $100\\,$M$_\\odot$, we find sensitive volume impr...

  15. The ELM Survey. VII. Orbital Properties of Low-Mass White Dwarf Binaries

    Science.gov (United States)

    Brown, Warren R.; Gianninas, A.; Kilic, Mukremin; Kenyon, Scott J.; Allende Prieto, Carlos

    2016-02-01

    We present the discovery of 15 extremely low-mass (5\\lt {log}g\\lt 7) white dwarf (WD) candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted extremely low-mass Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 M⊙ mean and 0.25 M⊙ dispersion. Thus extremely low-mass WDs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the WD binaries have a total mass below the Chandrasekhar mass, and thus are not type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive WDs and stable mass transfer AM CVn binaries. Based on observations obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

  16. Binary Encodings of Non-binary Constraint Satisfaction Problems: Algorithms and Experimental Results

    CERN Document Server

    Samaras, N; 10.1613/jair.1776

    2011-01-01

    A non-binary Constraint Satisfaction Problem (CSP) can be solved directly using extended versions of binary techniques. Alternatively, the non-binary problem can be translated into an equivalent binary one. In this case, it is generally accepted that the translated problem can be solved by applying well-established techniques for binary CSPs. In this paper we evaluate the applicability of the latter approach. We demonstrate that the use of standard techniques for binary CSPs in the encodings of non-binary problems is problematic and results in models that are very rarely competitive with the non-binary representation. To overcome this, we propose specialized arc consistency and search algorithms for binary encodings, and we evaluate them theoretically and empirically. We consider three binary representations; the hidden variable encoding, the dual encoding, and the double encoding. Theoretical and empirical results show that, for certain classes of non-binary constraints, binary encodings are a competitive op...

  17. A Speeding Binary in the Galactic Halo

    Science.gov (United States)

    Kohler, Susanna

    2016-04-01

    The recent discovery of a hyper-velocity binary star system in the halo of the Milky Way poses a mystery: how was this system accelerated to its high speed?Accelerating StarsUnlike the uniform motion in the Galactic disk, stars in the Milky Ways halo exhibit a huge diversity of orbits that are usually tilted relative to the disk and have a variety of speeds. One type of halo star, so-called hyper-velocity stars, travel with speeds that can approach the escape velocity of the Galaxy.How do these hyper-velocity stars come about? Assuming they form in the Galactic disk, there are multiple proposed scenarios through which they could be accelerated and injected into the halo, such as:Ejection after a close encounter with the supermassive black hole at the Galactic centerEjection due to a nearby supernova explosionEjection as the result of a dynamical interaction in a dense stellar population.Further observations of hyper-velocity stars are necessary to identify the mechanism responsible for their acceleration.J1211s SurpriseModels of J1211s orbit show it did not originate from the Galactic center (black dot). The solar symbol shows the position of the Sun and the star shows the current position of J1211. The bottom two panels show two depictions(x-y plane and r-z plane) of estimated orbits of J1211 over the past 10 Gyr. [Nmeth et al. 2016]To this end, a team of scientists led by Pter Nmeth (Friedrich Alexander University, Erlangen-Nrnberg) recently studied the candidate halo hyper-velocity star SDSS J121150.27+143716.2. The scientists obtained spectroscopy of J1211 using spectrographs at the Keck Telescope in Hawaii and ESOs Very Large Telescope in Chile. To their surprise, they discovered the signature of a companion in the spectra: J1211 is actually a binary!Nmeth and collaborators found that J1211, located roughly 18,000 light-years away, is moving at a rapid ~570 km/s relative to the galactic rest frame. The binary system consists of a hot (30,600 K) subdwarf and a

  18. Binaries and Globular Cluster Dynamics

    CERN Document Server

    Rasio, F A; Joshi, K J; Rasio, Frederic A.; Fregeau, John M.; Joshi, Kriten J.

    2001-01-01

    We summarize the results of recent theoretical work on the dynamical evolution of globular clusters containing primordial binaries. Even a very small initial binary fraction (e.g., 10%) can play a key role in supporting a cluster against gravothermal collapse for many relaxation times. Inelastic encounters between binaries and single stars or other binaries provide a very significant energy source for the cluster. These dynamical interactions also lead to the production of large numbers of exotic systems such as ultracompact X-ray binaries, recycled radio pulsars, double degenerate systems, and blue stragglers. Our work is based on a new parallel supercomputer code implementing Henon's Monte Carlo method for simulating the dynamical evolution of dense stellar systems in the Fokker-Planck approximation. This new code allows us to calculate very accurately the evolution of a cluster containing a realistic number of stars (N ~ 10^5 - 10^6) in typically a few hours to a few days of computing time. The discrete, s...

  19. Exoplanets Bouncing Between Binary Stars

    CERN Document Server

    Moeckel, Nickolas

    2012-01-01

    Exoplanetary systems are found not only among single stars, but also binaries of widely varying parameters. Binaries with separations of 100--1000 au are prevalent in the Solar neighborhood; at these separations planet formation around a binary member may largely proceed as if around a single star. During the early dynamical evolution of a planetary system, planet--planet scattering can eject planets from a star's grasp. In a binary, the motion of a planet ejected from one star has effectively entered a restricted three-body system consisting of itself and the two stars, and the equations of motion of the three body problem will apply as long as the ejected planet remains far from the remaining planets. Depending on its energy, escape from the binary as a whole may be impossible or delayed until the three-body approximation breaks down, and further close interactions with its planetary siblings boost its energy when it passes close to its parent star. Until then this planet may be able to transition from the ...

  20. Candidate gene prioritization with Endeavour.

    Science.gov (United States)

    Tranchevent, Léon-Charles; Ardeshirdavani, Amin; ElShal, Sarah; Alcaide, Daniel; Aerts, Jan; Auboeuf, Didier; Moreau, Yves

    2016-07-01

    Genomic studies and high-throughput experiments often produce large lists of candidate genes among which only a small fraction are truly relevant to the disease, phenotype or biological process of interest. Gene prioritization tackles this problem by ranking candidate genes by profiling candidates across multiple genomic data sources and integrating this heterogeneous information into a global ranking. We describe an extended version of our gene prioritization method, Endeavour, now available for six species and integrating 75 data sources. The performance (Area Under the Curve) of Endeavour on cross-validation benchmarks using 'gold standard' gene sets varies from 88% (for human phenotypes) to 95% (for worm gene function). In addition, we have also validated our approach using a time-stamped benchmark derived from the Human Phenotype Ontology, which provides a setting close to prospective validation. With this benchmark, using 3854 novel gene-phenotype associations, we observe a performance of 82%. Altogether, our results indicate that this extended version of Endeavour efficiently prioritizes candidate genes. The Endeavour web server is freely available at https://endeavour.esat.kuleuven.be/. PMID:27131783

  1. Empathy Development in Teacher Candidates

    Science.gov (United States)

    Boyer, Wanda

    2010-01-01

    Using a grounded theory research design, the author examined 180 reflective essays of teacher candidates who participated in a "Learning Process Project," in which they were asked to synthesize and document their discoveries about the learning process over the course of a completely new learning experience as naive learners. This study explored…

  2. Candidate Prediction Models and Methods

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Madsen, Henrik;

    2005-01-01

    This document lists candidate prediction models for Work Package 3 (WP3) of the PSO-project called ``Intelligent wind power prediction systems'' (FU4101). The main focus is on the models transforming numerical weather predictions into predictions of power production. The document also outlines the...

  3. Using Binary Code Instrumentation in Computer Security

    Directory of Open Access Journals (Sweden)

    Marius POPA

    2013-01-01

    Full Text Available The paper approaches the low-level details of the code generated by compilers whose format permits outside actions. Binary code modifications are manually done when the internal format is known and understood, or automatically by certain tools developed to process the binary code. The binary code instrumentation goals may be various from security increasing and bug fixing to development of malicious software. The paper highlights the binary code instrumentation techniques by code injection to increase the security and reliability of a software application. Also, the paper offers examples for binary code formats understanding and how the binary code injection may be applied.

  4. Global blending optimization of laminated composites with discrete material candidate selection and thickness variation

    DEFF Research Database (Denmark)

    Sørensen, Søren N.; Stolpe, Mathias

    2015-01-01

    distinct choice among predefined numbers of candidates. The laminate thickness is variable but the number of plies must be integer. We solve the convex mixed binary non-linear programming problem by an outer approximation cutting-plane method augmented with a few heuristics to accelerate the convergence...... but is, however, convex in the original mixed binary nested form. Convexity is the foremost important property of optimization problems, and the proposed method can guarantee the global or near-global optimal solution; unlike most topology optimization methods. The material selection is limited to a...... rate. The capabilities of the method and the effect of active versus inactive manufacturing constraints are demonstrated on several numerical examples of limited size, involving at most 320 binary variables. Most examples are solved to guaranteed global optimality and may constitute benchmark examples...

  5. SLoWPoKES-II: 100,000 Wide Binaries Identified in SDSS without Proper Motions

    CERN Document Server

    Dhital, Saurav; Stassun, Keivan G; Schluns, Kyle J; Massey, Angela P

    2015-01-01

    We present the SLoWPoKES-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey by matching photometric distances. The candidate pairs are vetted by comparing the stellar information. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without need of proper motions. 105,537 visual binaries with angular separations of $\\sim$1-20", were identified, each with a probability of chance alignment of $\\lesssim$5%. This is the largest catalog of bona fide wide binaries to date, and it contains a diversity of systems---in mass, mass ratios, binary separations, metallicity, and evolutionary states---that should facilitate follow-up studies to characterize the properties of M dwarfs and white dwarfs. There is a subtle but definitive suggestion of multiple populations in the physical separation distribution, supp...

  6. Double-lined Spectroscopic Binary Stars in the Radial Velocity Experiment Survey

    CERN Document Server

    Matijevic, G; Munari, U; Bienayme, O; Binney, J; Bland-Hawthorn, J; Boeche, C; Campbell, R; Freeman, K C; Gibson, B; Gilmore, G; Grebel, E K; Helmi, A; Navarro, J F; Parker, Q A; Seabroke, G M; Siebert, A; Siviero, A; Steinmetz, M; Watson, F G; Williams, M; Wyse, R F G; 10.1088/0004-6256/140/1/184

    2010-01-01

    We devise a new method for the detection of double-lined binary stars in a sample of the Radial Velocity Experiment (RAVE) survey spectra. The method is both tested against extensive simulations based on synthetic spectra, and compared to direct visual inspection of all RAVE spectra. It is based on the properties and shape of the cross-correlation function, and is able to recover ~80% of all binaries with an orbital period of order 1 day. Systems with periods up to 1 year are still within the detection reach. We have applied the method to 25,850 spectra of the RAVE second data release and found 123 double-lined binary candidates, only eight of which are already marked as binaries in the SIMBAD database. Among the candidates, there are seven that show spectral features consistent with the RS CVn type (solar type with active chromosphere) and seven that might be of W UMa type (over-contact binaries). One star, HD 101167, seems to be a triple system composed of three nearly identical G-type dwarfs. The tested cl...

  7. Dancing in the Dark: New Brown Dwarf Binaries from Kernel Phase Interferometry

    CERN Document Server

    Pope, Benjamin; Tuthill, Peter

    2013-01-01

    This paper revisits a sample of ultracool dwarfs in the Solar neighborhood previously observed with the Hubble Space Telescope's NICMOS NIC1 instrument. We have applied a novel high angular resolution data analysis technique based on the extraction and fitting of kernel phases to archival data. This was found to deliver a dramatic improvement over earlier analysis methods, permitting a search for companions down to projected separations of $\\sim$1 AU on NIC1 snapshot images. We reveal five new close binary candidates and present revised astrometry on previously-known binaries, all of which were recovered with the technique. The new candidate binaries have sufficiently close separation to determine dynamical masses in a short-term observing campaign. We also present four marginal detections of objects which may be very close binaries or high contrast companions. Including only confident detections within 19 parsecs, we report a binary fraction of at least $\\epsilon_b = 17.2^{+5.7}_{-3.7}%$. The results reporte...

  8. The structure of contact binaries

    CERN Document Server

    Kaehler, H

    2003-01-01

    In radiative layers of rotating stars the luminosity carried by circulation currents through a surface of constant entropy (circulation luminosity) is shown to be positive. The corresponding decrease in the temperature gradient is important in the secondary of contact binaries. This result removes the deadlock in the theory of contact binaries. The resulting treatment of contact binaries is investigated, assuming thermal equilibrium. If the circulation luminosity is adjusted to give a prescribed temperature difference between the components, details turn out to be unimportant. The temperature difference is bound to be positive. The fractional extent of radiative regions is larger in the secondary than in the primary. In the course of evolution the period increases and the mass ratio decreases. A survey of unevolved and evolved contact configurations is presented. Observational tests are passed. In stable systems the degree of contact is small. Stable systems in the period-colour diagram, unevolved and evolved...

  9. Practical Binary Adaptive Block Coder

    CERN Document Server

    Reznik, Yuriy A

    2007-01-01

    This paper describes design of a low-complexity algorithm for adaptive encoding/ decoding of binary sequences produced by memoryless sources. The algorithm implements universal block codes constructed for a set of contexts identified by the numbers of non-zero bits in previous bits in a sequence. We derive a precise formula for asymptotic redundancy of such codes, which refines previous well-known estimate by Krichevsky and Trofimov, and provide experimental verification of this result. In our experimental study we also compare our implementation with existing binary adaptive encoders, such as JBIG's Q-coder, and MPEG AVC (ITU-T H.264)'s CABAC algorithms.

  10. Coalescing binaries and Doppler experiments

    OpenAIRE

    Vecchio, A.; Bertotti, B.; Iess, L.

    1997-01-01

    We discuss the sensitivity of the CASSINI experiments to gravitational waves emitted by the in-spiral of compact binaries. We show that the maximum distance reachable by the instrument is $\\sim 100$ Mpc. In particular, CASSINI can detect massive black hole binaries with chirp mass $\\simgt 10^6 \\Ms$ in the Virgo Cluster with signal-to-noise ratio between 5 and 30 and possible compact objects of mass $\\simgt 30 \\Ms$ orbiting the massive black hole that our Galactic Centre is likely to harbour.

  11. Rectangular Decomposition of Binary Images

    Czech Academy of Sciences Publication Activity Database

    Suk, Tomáš; Höschl, Cyril; Flusser, Jan

    Berlin : Springer, 2012 - (Blanc-Talon, J.; Popescu, D.; Philips, W.; Scheunders, P.), s. 213-224 ISBN 978-3-642-33139-8. - (Lecture Notes in Computer Science. 7517). [Advanced Concepts for Intelligent Vision Systems (Acivs 2012). Brno (CZ), 04.09.2012-07.09.2012] R&D Projects: GA ČR GAP103/11/1552 Institutional support: RVO:67985556 Keywords : binary image decomposition * generalized delta-method * distance transformation * quadtree * bipartite graph * image compression * fast convolution Subject RIV: IN - Informatics, Computer Science http://library.utia.cas.cz/separaty/2012/ZOI/suk-rectangular decomposition of binary images.pdf

  12. The quest for collapsed/frozen stars in single-line spectroscopic binary systems

    CERN Document Server

    Trimble, Virginia

    2014-01-01

    Black holes are now commonplace, among the stars, in Galactic centers, and perhaps other places. But within living memory, their very existence was doubted by many, and few chose to look for them. Zeldovich and Guseinov were first, followed by Trimble and Thorne, using a method that would have identified HDE 226868 as a plausible candidate, if it had been in the 1968 catalogue of spectroscopic binaries. That it was not arose from an unhappy accident in the observing program of Daniel M. Popper long before the discovery of X-ray binaries and the identification of Cygnus X-1 with that hot, massive star and its collapsed companion.

  13. The Magellanic Bridge: evidence for a population of X-ray binaries

    OpenAIRE

    McBride, V. A.; Bird, A. J.; Coe, M. J.; Townsend, L. J.; Corbet, R. H. D.; Haberl, F.

    2009-01-01

    INTEGRAL observations of the Small Magellanic Cloud region have resulted in the serendipitous detection of two transient hard X-ray sources in the Magellanic Bridge. In this paper we present the timing and spectral characteristics of these sources across the 2-100 keV energy range, which, in conjunction with their optical counterparts, demonstrate that they are high mass X-ray binaries in the Magellanic Bridge. Together with one previously known high mass X-ray binary system, and three candid...

  14. Kepler Eclipsing Binaries with Stellar Companions

    CERN Document Server

    Gies, D R; Guo, Z; Lester, K V; Orosz, J A; Peters, G J

    2015-01-01

    Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.

  15. Flares from a new Integral hard X-ray source, IGR J17407-2808, likely associated with the ROSAT source SBM 10

    DEFF Research Database (Denmark)

    Kretschmar, P.; Mereghetti, S.; Hermsen, W.;

    2004-01-01

    detected. The last flare, with peak fluxes of 0.8±0.1 Crab and 0.6±0.1 Crab in the energy ranges 20-40 keV and 40-60 keV respectively, triggered an automatic alert message of the Integral Burst Alert System (IBAS Alert #2010) which led to the discovery of the source (Gotz et al., GCN Circ. #2793). The...... observations of [SBM2001] 10 have been published up to date. The flares were observed with the IBIS instrument in the 20-60 keV energy range, starting at MJD 53287.6310 and over a timespan of 2000 seconds finishing in a strong flare at MJD 53287.6327. Before and after this time period the source was not...... source was outside the FOV of the JEM-X and OMC monitor instruments during this flare. Note that the position of J17407-2808 is inconsistent with that of the X-ray burster SLX 1737-282 [AX J1740.7-2818] (in't Zand et al. 2002, A&A 389, L43), which is just ~11 arcmin away. The correct Integral attitude is...

  16. IAEA Director General candidates announced

    International Nuclear Information System (INIS)

    Full text: The IAEA today confirms receipt of the nomination of five candidates for Director General of the IAEA. Nominations of the following individuals have been received by the Chairperson of the IAEA Board of Governors, Ms. Taous Feroukhi: Mr. Jean-Pol Poncelet of Belgium; Mr. Yukiya Amano of Japan; Mr. Ernest Petric of Slovenia; Mr. Abdul Samad Minty of South Africa; and Mr. Luis Echavarri of Spain. The five candidates were nominated in line with a process approved by the Board in October 2008. IAEA Director General Mohamed ElBaradei's term of office expires on 30 November 2009. He has served as Director General since 1997 and has stated that he is not available for a fourth term of office. (IAEA)

  17. VALUE ORIENTATIONS OF TEACHER CANDIDATES

    OpenAIRE

    YAPICI, Asım; KUTLU, M.Oğuz; BİLİCAN, F.Işıl

    2012-01-01

    Abstract This cross-sectional, descriptive study examined the change in values in time among teacher candidates. The Schwartz Values Inventory was administered to 708 freshmen and senior students studying at Cukurova University, Education Faculty. The results have shown that the students at the department of Science Education valued power, achievement, stimulation; the department of English Teaching Education valued hedonism; and the department of Education of Religious Culture valued un...

  18. Frame theory for binary vector spaces

    OpenAIRE

    Bodmann, Bernhard G.; Le, My; Reza, Letty; Tobin, Matthew; Tomforde, Mark

    2009-01-01

    We develop the theory of frames and Parseval frames for finite-dimensional vector spaces over the binary numbers. This includes characterizations which are similar to frames and Parseval frames for real or complex Hilbert spaces, and the discussion of conceptual differences caused by the lack of a proper inner product on binary vector spaces. We also define switching equivalence for binary frames, and list all equivalence classes of binary Parseval frames in lowest dimensions, excluding cases...

  19. Using Binary Code Instrumentation in Computer Security

    OpenAIRE

    Marius POPA; Sergiu Marin CAPISIZU

    2013-01-01

    The paper approaches the low-level details of the code generated by compilers whose format permits outside actions. Binary code modifications are manually done when the internal format is known and understood, or automatically by certain tools developed to process the binary code. The binary code instrumentation goals may be various from security increasing and bug fixing to development of malicious software. The paper highlights the binary code instrumentation techniques by code injection to...

  20. Population Synthesis for Symbiotic X-ray Binaries

    CERN Document Server

    Lu, G -L; Postnov, K A; Yungelson, L R; Kuranov, A G; Wang, N

    2012-01-01

    Symbiotic X-ray binaries (SyXBs) comprise a rare class of low-mass X-ray binaries. We study the Galactic SyXBs, which we consider as detached binaries composed of low-mass giants and wind-fed neutron star companions, by simulation of the interaction of a magnetized neutron star (NS) with its environment and utilizing a population synthesis code. We focus mainly on the parameters that influence observational appearance of the SyXB: the donor wind velocity (vw) and the angular momentum distribution in the shell of matter settling onto NS. We estimate the birthrate of SyXB as $\\sim 4.1\\times 10^{-5}$ yr$^{-1}$ to $ \\sim 6.6\\times 10^{-6}$ yr$^{-1}$ and their number in the Galaxy as $\\sim$(100 -- 1000). Assumed stellar wind velocity from cool giants is the input parameter that influences the model SyXBs population most. Among known SyXBs or candidate systems, 4U 1954+31 and IGR J16358-4724 in which NS have very long spin periods may host quasi-spherically accreting NSs. GX 1+4 has a peculiar long-term spin behavi...

  1. Benchmark ultra-cool dwarfs in widely separated binary systems

    Directory of Open Access Journals (Sweden)

    Jones H.R.A.

    2011-07-01

    Full Text Available Ultra-cool dwarfs as wide companions to subgiants, giants, white dwarfs and main sequence stars can be very good benchmark objects, for which we can infer physical properties with minimal reference to theoretical models, through association with the primary stars. We have searched for benchmark ultra-cool dwarfs in widely separated binary systems using SDSS, UKIDSS, and 2MASS. We then estimate spectral types using SDSS spectroscopy and multi-band colors, place constraints on distance, and perform proper motions calculations for all candidates which have sufficient epoch baseline coverage. Analysis of the proper motion and distance constraints show that eight of our ultra-cool dwarfs are members of widely separated binary systems. Another L3.5 dwarf, SDSS 0832, is shown to be a companion to the bright K3 giant η Cancri. Such primaries can provide age and metallicity constraints for any companion objects, yielding excellent benchmark objects. This is the first wide ultra-cool dwarf + giant binary system identified.

  2. Discs in misaligned binary systems

    Science.gov (United States)

    Rawiraswattana, Krisada; Hubber, David A.; Goodwin, Simon P.

    2016-08-01

    We perform SPH simulations to study precession and changes in alignment between the circumprimary disc and the binary orbit in misaligned binary systems. We find that the precession process can be described by the rigid-disc approximation, where the disc is considered as a rigid body interacting with the binary companion only gravitationally. Precession also causes change in alignment between the rotational axis of the disc and the spin axis of the primary star. This type of alignment is of great important for explaining the origin of spin-orbit misaligned planetary systems. However, we find that the rigid-disc approximation fails to describe changes in alignment between the disc and the binary orbit. This is because the alignment process is a consequence of interactions that involve the fluidity of the disc, such as the tidal interaction and the encounter interaction. Furthermore, simulation results show that there are not only alignment processes, which bring the components towards alignment, but also anti-alignment processes, which tend to misalign the components. The alignment process dominates in systems with misalignment angle near 90°, while the anti-alignment process dominates in systems with the misalignment angle near 0° or 180°. This means that highly misaligned systems will become more aligned but slightly misaligned systems will become more misaligned.

  3. A Galactic Binary Detection Pipeline

    Science.gov (United States)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  4. CFD Simulations of Binary Nucleation

    Czech Academy of Sciences Publication Activity Database

    Herrmann, E.; Brus, David; Hyvärinen, A-P.; Kulmala, M.

    Helsinki : -, 2010, P3U16. ISBN N. [International Aerosol Conference IAC 2010. Helsinki (FI), 29.08.2010-03.09.2010] Grant ostatní: FCR(FI) 1118615 Institutional research plan: CEZ:AV0Z40720504 Keywords : nucleation * binary * parameterization Subject RIV: CF - Physical ; Theoretical Chemistry www.iac2010.fi

  5. Eccentricity distribution of wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    A sample of 477 solar-type binaries within 67pc with projected separations larger than 50AU is studied by a new statistical method. Speed and direction of the relative motion are determined from the short observed arcs or known orbits, and their joint distribution is compared to the numerical simulations. By inverting the observed distribution with the help of simulations, we find that average eccentricity of wide binaries is 0.59+-0.02 and the eccentricity distribution can be modeled as f(e) ~= 1.2 e + 0.4. However, wide binaries containing inner subsystems, i.e. triple or higher-order multiples, have significantly smaller eccentricities with the average e = 0.52+-0.05 and the peak at e ~ 0.5. We find that the catalog of visual orbits is strongly biased against large eccentricities. A marginal evidence of eccentricity increasing with separation (or period) is found for this sample. Comparison with spectroscopic binaries proves the reality of the controversial period-eccentricity relation. The average eccentr...

  6. A Redundant Binary Algorithm for RSA

    Institute of Scientific and Technical Information of China (English)

    施荣华

    1996-01-01

    The normal form and modified normal form for binary redundant representation are defined.A redundant binary algorithm to compute modular exponentiation for very large integers is proposed.It is shown that the proposed algorithm requires the minimum number of basic operations(modular multiplications)among all possible binary redundant representations.

  7. Competitive learning for binary valued data

    OpenAIRE

    Leisch, Friedrich; Weingessel, Andreas; Dimitriadou, Evgenia

    1998-01-01

    We propose a new approach for using online competitive learning on binary data. The usual Euclidean distance is replaced by binary distance measures, which take possible asymmetries of binary data into account and therefore provide a "different point of view" for looking at the data. The method is demonstrated on two artificial examples and applied on tourist marketing research data. (author's abstract)

  8. New prospects for observing and cataloguing exoplanets in well-detached binaries

    Science.gov (United States)

    Schwarz, R.; Funk, B.; Zechner, R.; Bazsó, Á.

    2016-08-01

    This paper is devoted to study the circumstances favourable to detect circumstellar and circumbinary planets in well-detached binary-star systems using eclipse timing variations (ETVs). We investigated the dynamics of well-detached binary star systems with a star separation from 0.5 to 3 au, to determine the probability of the detection of such variations with ground-based telescopes and space telescopes (like former missions CoRoT and Kepler and future space missions Plato, Tess and Cheops). For the chosen star separations both dynamical configurations (circumstellar and circumbinary) may be observable. We performed numerical simulations by using the full three-body problem as dynamical model. The dynamical stability and the ETVs are investigated by computing ETV maps for different masses of the secondary star and the exoplanet (Earth, Neptune and Jupiter size). In addition we changed the planet's and binary's eccentricities. We conclude that many amplitudes of ETVs are large enough to detect exoplanets in binary-star systems. As an application, we prepared statistics of the catalogue of exoplanets in binary star systems which we introduce in this article and compared the statistics with our parameter-space which we used for our calculations. In addition to these statistics of the catalogue we enlarged them by the investigation of well-detached binary star systems from several catalogues and discussed the possibility of further candidates.

  9. The Impact of Stellar Multiplicity on Planetary Systems, I.: The Ruinous Influence of Close Binary Companions

    CERN Document Server

    Kraus, Adam L; Huber, Daniel; Mann, Andrew W; Dupuy, Trent J

    2016-01-01

    The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry (NRM) on the Keck-II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of 0.4; we instead only found 23 companions (a 4.6 sigma deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a_cut and a suppression factor inside that cutoff S_bin, we find with correlated uncertainties that inside a_cut = 47 +59/-23 AU, the planet occurrence rate in...

  10. Planetary Candidates Observed by \\ik V: Planet Sample from Q1-Q12 (36 Months)

    CERN Document Server

    Rowe, Jason F; Antoci, Victoria; Barclay, Thomas; Batalha, Natalie M; Borucki, William J; Burke, Christopher J; Bryson, Steven T; Caldwell, Douglas A; Campbell, Jennifer R; Catanzarite, Joseph H; Christiansen, Jessie L; Cochran, William; Gilliland, Ronald L; Girouard, Forrest R; Haas, Michael R; Helminiak, Krzysztof G; Henze, Christopher E; Hoffman, Kelsey L; Howell, Steve B; Huber, Daniel; Hunter, Roger C; Jang-Condell, Hannah; Jenkins, Jon M; Klaus, Todd C; Latham, David W; Li, Jie; Lissauer, Jack J; McCauliff, Sean D; Morris, Robert L; Mullally, F; Ofir, Aviv; Quarles, Billy; Quintana, Elisa; Sabale, Anima; Seader, Shawn; Shporer, Avi; Smith, Jeffrey C; Steffen, Jason H; Still, Martin; Tenenbaum, Peter; Thompson, Susan E; Twicken, Joseph D; Van Laerhoven, Christa; Wolfgang, Angie; Zamudio, Khadeejah A

    2015-01-01

    The Kepler mission discovered 2842 exoplanet candidates with 2 years of data. We provide updates to the Kepler planet candidate sample based upon 3 years (Q1-Q12) of data. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars and instrumental systematics, 855 additional planetary candidates have been discovered, bringing the total number known to 3697. We provide revised transit parameters and accompanying posterior distributions based on a Markov Chain Monte Carlo algorithm for the cumulative catalogue of Kepler Objects of Interest. There are now 130 candidates in the cumulative catalogue that receive less than twice the flux the Earth receives and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen candidates meeting both criteria, roughly doubling the number of candidate Earth analogs. A majority of planetary candidates have a high probability of being bonafide planets, however, there are populations of likely false-positives. We discuss and s...

  11. PLANETARY CANDIDATES OBSERVED BY KEPLER. III. ANALYSIS OF THE FIRST 16 MONTHS OF DATA

    International Nuclear Information System (INIS)

    New transiting planet candidates are identified in 16 months (2009 May-2010 September) of data from the Kepler spacecraft. Nearly 5000 periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1108 viable new planet candidates, bringing the total count up to over 2300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis that identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the candidates. Ephemerides (transit epoch, T 0, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (R P/R *), reduced semimajor axis (d/R *), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (201% for candidates smaller than 2 R ⊕ compared to 53% for candidates larger than 2 R ⊕) and those at longer orbital periods (124% for candidates outside of 50 day orbits versus 86% for candidates inside of 50 day orbits). The gains are larger than expected from increasing the observing window from 13 months (Quarters 1-5) to 16 months (Quarters 1-6) even in regions of parameter space where one would have expected the previous catalogs to be complete. Analyses of planet frequencies based on previous catalogs will be affected by such incompleteness. The fraction of all planet candidate host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the habitable zone are forthcoming if, indeed, such planets are abundant.

  12. The historical 1900 and 1913 outbursts of the binary blazar candidate OJ287

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Bašta, M.; Pihajoki, P.; Valtonen, M.J.

    2013-01-01

    Roč. 559, October (2013), A20/1-A20/9. ISSN 0004-6361 Institutional support: RVO:67985815 Keywords : observational methods * OJ287 * photometric techniques Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.479, year: 2013

  13. An eclipsing binary black hole candidate system in the blazar Mrk 421

    CERN Document Server

    Benitez, E; Fraija, N; Hernandez, X; Lopez-Corona, O; Lora-Clavijo, F D; Mendoza, S

    2015-01-01

    Removing strong outbursts from multiwavelength light curves of the blazar Mrk 421, we construct outburstless time series for this system. A model-independent power spectrum light curve analysis in the optical, hard X-ray and gamma-rays of this outburstless state shows clear evidence for a periodicity of \\approx 400 days. A subsequent full maximum likelihood analysis fitting an eclipse model confirms a periodicity of 387.16 days. The power spectrum of the signal in the outburstless state of the source does not follow a flicker noise behaviour and so, the system producing it is not self-organised. This means that the periodicity is not produced by any internal physical processes associated to the central engine. The simplest physical mechanism to which this periodicity could be ascribed is a dynamical effect produced by an orbiting supermassive black hole companion of mass \\sim 10^7 M_\\odot eclipsing the central black hole, which has a mass \\sim 10^8 M_\\odot. The optimal model restricts the physics of the eclip...

  14. Very long term observations of blazars candidates for supermassive black hole binaries

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Bašta, Milan

    Trieste: Proceedings of Science, 2008, s. 1-7. ISSN 1824-8039. [Workshop on Blazar Variability across the Electromagnetic Spectrum. Palaiseau (FR), 22.04.2008-25.04.2008] R&D Projects: GA ČR GA205/08/1207; GA ČR GA205/05/2167 Institutional research plan: CEZ:AV0Z10030501 Keywords : cosmic sources * supermassive black holes * high-energy sources Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://pos.sissa.it

  15. 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.

  16. New planetary and EB candidates from Campaigns 1-6 of the K2 mission

    CERN Document Server

    Barros, S C C; Deleuil, M

    2016-01-01

    With only two functional reaction wheels, Kepler cannot maintain stable pointing at its original target field and entered a new mode of observation called K2. Our method is based on many years of experience in planet hunting for the CoRoT mission. Due to the unstable pointing, K2 light curves present systematics that are correlated with the target position in the CCD. Therefore, our pipeline also includes a decorrelation of this systematic noise. Our pipeline is optimised for bright stars for which spectroscopic follow-up is possible. We achieve a maximum precision on 6 hours of 6 ppm. The decorrelated light curves are searched for transits with an adapted version of the CoRoT alarm pipeline. We present 172 planetary candidates and 327 eclipsing binary candidates from campaigns 1, 2, 3, 4, 5 and 6 of K2. Both the planetary candidates and eclipsing binary candidates lists are made public to promote follow-up studies. The light curves will also be available to the community.

  17. The Magellanic Bridge: evidence for a population of X-ray binaries

    CERN Document Server

    McBride, V A; Coe, M J; Townsend, L J; Corbet, R H D; Haberl, F

    2009-01-01

    INTEGRAL observations of the Small Magellanic Cloud region have resulted in the serendipitous detection of two transient hard X-ray sources in the Magellanic Bridge. In this paper we present the timing and spectral characteristics of these sources across the 2-100 keV energy range, which, in conjunction with their optical counterparts, demonstrate that they are high mass X-ray binaries in the Magellanic Bridge. Together with one previously known high mass X-ray binary system, and three candidates, these sources represent an emerging population of X-ray binaries in the Bridge, probably initiated by tidally induced star formation as a result of the gravitational interaction between the Large and Small Magellanic Clouds.

  18. Supermassive binary black holes - possible observational effects in the x-ray emission

    Directory of Open Access Journals (Sweden)

    Jovanović Predrag

    2014-01-01

    Full Text Available Here we discuss the possible observational effects in the X-ray emission from two relativistic accretion disks in a supermassive binary black hole system. For that purpose we developed a model and performed numerical simulations of the X-ray radiation from a relativistic accretion disk around a supermassive black hole, based on the ray-tracing method in the Kerr metric, and applied it to the case of the close binary supermassive black holes. Our results indicate that the broad Fe Kα line is a powerful tool for detecting such systems and studying their properties. The most favorable candidates for observational studies are the supermassive binary black holes in the galactic mergers during the phase when the orbital velocities of their components are very large and exceed several thousand kms -1. [Projekat Ministarstva nauke Republike Srbije, br. 176003: Gravitation and the Large Scale Structure of the Universe i br. 176001: Astrophysical Spectroscopy of Extragalactic Objects

  19. Computational Identification of Promising Thermoelectric Materials Among Known Quasi-2D Binary Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gorai, Prashun; Toberer, Eric S.; Stevanovic, Vladan

    2016-07-28

    Quasi low-dimensional structures are abundant among known thermoelectric materials, primarily because of their low lattice thermal conductivities. In this work, we have computationally assessed the potential of 427 known binary quasi-2D structures in 272 different chemistries for thermoelectric performance. To assess the thermoelectric performance, we employ an improved version of our previously developed descriptor for thermoelectric performance [Yan et al., Energy Environ. Sci., 2015, 8, 983]. The improvement is in the explicit treatment of van der Waals interactions in quasi-2D materials, which leads to significantly better predictions of their crystal structures and lattice thermal conductivities. The improved methodology correctly identifies known binary quasi-2D thermoelectric materials such as Sb2Te3, Bi2Te3, SnSe, SnS, InSe, and In2Se3. As a result, we propose candidate quasi-2D binary materials, a number of which have not been previously considered for thermoelectric applications.

  20. Promising new cryogenic seal candidate

    International Nuclear Information System (INIS)

    Of the five seal candidates considered for the main propellant system of the Space Shuttle, only one candidate, the fluoroplastic Halar, satisfied all tests including the critical LO2 impact test and the cryogenic compression sealability test. Radiation-cross-linked Halar is a tough, strong thermoplastic that not only endured one hundred 2200 N compression cycles at 83 K while mounted in a standard military O-ring gland without cracking or deforming, but improved in sealability as a result of this cycling. Although these Halar O-rings require much higher sealing forces (approximately 500 N) at room temperature than rubber O-rings, on cooling to cryogenic temperatures the required sealing force only doubles, whereas the sealing force for rubber O-rings increases eightfold. Although these Halar O-rings were inadequately cross-linked, they still exhibited promise as LO2-compatible cryogenic seals. It is expected that their high-temperature properties can be greatly improved by higher degrees of cross-linking (e.g., by 20 mrad of radiation) without compromising their already excellent low-temperature properties. A direct comparison should then be obtained between the best of the cross-linked Halar compounds and the current commercial cryogenic seal materials, filled Teflon and Kel-F

  1. Remnants of compact binary mergers

    CERN Document Server

    Domainko, W

    2006-01-01

    We investigate the long-term evolution and observability of remnants originating from the merger of compact binary systems and discuss the differences to supernova remnants. Compact binary mergers expel much smaller amounts of mass at much higher velocities, as compared to supernovae, which will affect the dynamical evolution of their remnants. The ejecta of mergers consist of very neutron rich nuclei. Some of these neutron rich nuclei will produce observational signatures in form of gamma ray lines during their decay. The composition of the ejecta might even give interesting constraints about the internal structure of the neutron star. We further discuss the possibility that merger remnants appear as recently discovered 'dark accelerators' which are extended TeV sources which lack emission in other bands.

  2. Event Rates for Binary Inspiral

    CERN Document Server

    Kalogera, V

    2001-01-01

    Double compact objects (neutron stars and black holes) found in binaries with small orbital separations are known to spiral in and are expected to coalesce eventually because of the emission of gravitational waves. Such inspiral and merger events are thought to be primary sources for ground based gravitational-wave interferometric detectors (such as LIGO). Here, we present a brief review of estimates of coalescence rates and we examine the origin and relative importance of uncertainties associated with the rate estimates. For the case of double neutron star systems, we compare the most recent rate estimates to upper limits derived in a number of different ways. We also discuss the implications of the formation of close binaries with two non-recycled pulsars.

  3. Low-Mass X-ray Binaries and Globular Clusters in Centaurus A

    OpenAIRE

    Jordan, Andres; Sivakoff, Gregory R.; McLaughlin, Dean E.; Blakeslee, John P; Evans, Daniel A.; Kraft, Ralph P.; Hardcastle, Martin J.; Peng, Eric W.; Cote, Patrick; Croston, Judith H.; Juett, Adrienne M.; Minniti, Dante; Raychaudhury, Somak; Sarazin, Craig L.; Worrall, Diana M.

    2007-01-01

    We present results of Hubble Space Telescope and Chandra X-ray Observatory observations of globular clusters (GCs) and low-mass X-ray binaries (LMXBs) in the central regions of Centaurus A. Out of 440 GC candidates we find that 41 host X-ray point sources that are most likely LMXBs. We fit King models to our GC candidates in order to measure their structural parameters. We find that GCs that host LMXBs are denser and more compact, and have higher encounter rates and concentrations than the GC...

  4. The Ages of High Mass X-ray Binaries in NGC 2403 and NGC 300

    OpenAIRE

    Williams, Benjamin F.; Binder, Breanna A.; Dalcanton, Julianne J.; Eracleous, Michael; Dolphin, Andrew

    2013-01-01

    We have examined resolved stellar photometry from HST imaging surrounding 18 high-mass X-ray binary (HMXB) candidates in NGC 300 and NGC 2403 as determined from combined Chandra/HST analysis. We have fit the color-magnitude distribution of the surrounding stars with stellar evolution models. All but one region in NGC 300 and two in NGC 2403 contain a population with an age between 20 and 70 Myr. One of the candidates is the ultraluminous X-ray source (ULX) in NGC 2403, which we associate with...

  5. Modified binary particle swam optimization

    Institute of Scientific and Technical Information of China (English)

    Sangwook Lee; Sangmoon Soak; Sanghoun Oh; Witold Pedrycz; Moongu Jeon

    2008-01-01

    This paper presents a modified binary particle swarm optimization(BPSO)which adopts concepts of the genotype-phenotype rep-resentation and the mutation operator of genetic algorithms.Its main feature is that the BPSO can be treated as a continuous PSO.The proposed BPSO algorithm is tested on various benchmark functions,and its performance is compared with that of the original BPSO.Experimental results show that the modified BPSO outperforms the original BPSO algorithm.

  6. Tides in asynchronous binary systems

    OpenAIRE

    Toledano, Oswaldo; Moreno, Edmundo; Koenigsberger, Gloria; Detmers, R.; Langer, Norbert

    2006-01-01

    Stellar oscillations are excited in non-synchronously rotating stars in binary systems due to the tidal forces. Tangential components of the tides can drive a shear flow which behaves as a differentially forced rotating structure in a stratified outer medium. In this paper we show that our single-layer approximation for the calculation of the forced oscillations yields results that are consistent with the predictions for the synchronization timescales in circular orbits. In addition, calibrat...

  7. Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data

    DEFF Research Database (Denmark)

    Batalha, Natalie M.; Rowe, Jason F.; Bryson, Stephen T.;

    2012-01-01

    binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the new candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (Rp/R*), reduced semi-major axis (d/R*), and impact......New transiting planet candidates are identified in sixteen months (May 2009 - September 2010) of data from the Kepler spacecraft. Nearly five thousand periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1,091 viable new planet candidates...... orbits). The gains are larger than expected from increasing the observing window from thirteen months (Quarter 1-- Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the benefit of continued development of pipeline analysis software. The fraction of all host stars with multiple...

  8. A Fast Distributed Algorithm for Association Rule Mining Based on Binary Coding Mapping Relation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Association rule mining is an important issue in data mining. The paper proposed an binary system based method to generate candidate frequent itemsets and corresponding supporting counts efficiently, which needs only some operations such as "and", "or" and "xor". Applying this idea in the existed distributed association rule mining algorithm FDM, the improved algorithm BFDM is proposed. The theoretical analysis and experiment testify that BFDM is effective and efficient.

  9. The end of the MACHO era- revisited: new limits on MACHO masses from halo wide binaries

    CERN Document Server

    Monroy-Rodríguez, Miguel A

    2014-01-01

    In order to determine an upper bound for the mass of the massive compact halo objets (MACHOs) we use the halo binaries contained in a recent catalog (Allen \\& Monroy-Rodr\\'{\\i}guez 2013). To dynamically model their interactions with massive perturbers a Monte Carlo simulation is conducted, using an impulsive approximation method and assuming a galactic halo constituted by massive particles of a characteristic mass. The results of such simulations are compared with several subsamples of our improved catalog of candidate halo wide binaries. In accordance with Quinn et al. (2009) we also find our results to be very sensitive to the widest binaries. However, our larger sample, together with the fact that we can obtain galactic orbits for 150 of our systems, allows a more reliable estimate of the maximum MACHO mass than that obtained previously. If we employ the entire sample of 211 candidate halo stars we obtain an upper limit of $112 M_\\sun$. However, using the 150 binaries in our catalog with computed galac...

  10. Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications

    Directory of Open Access Journals (Sweden)

    S. Komossa

    2012-01-01

    Full Text Available Supermassive black holes (SMBHs may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically offset from their host galaxies. The presence of the “kicks” has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of active galactic nuclei (AGN. Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which have emerged, including follow-up studies of the candidate recoiling SMBH of SDSSJ092712.65+294344.0.

  11. Spectral analysis of Kepler SPB and Beta Cep candidate stars

    CERN Document Server

    Lehmann, H; Semaan, T; Gutiérrez, J; Smalley, B; Briquet, M; Shulyak, D; Tsymbal, V; de Cat, P

    2010-01-01

    We determine the fundamental parameters of SPB and Beta Cep candidate stars observed by the Kepler satellite mission and estimate the expected types of non-radial pulsators by comparing newly obtained high-resolution spectra with synthetic spectra computed on a grid of stellar parameters assuming LTE and check for NLTE effects for the hottest stars. For comparison, we determine Teff independently from fitting the spectral energy distribution of the stars obtained from the available photometry. We determine Teff, log(g), micro-turbulent velocity, vsin(i), metallicity, and elemental abundance for 14 of the 16 candidate stars, two of the stars are spectroscopic binaries. No significant influence of NLTE effects on the results could be found. For hot stars, we find systematic deviations of the determined effective temperatures from those given in the Kepler Input Catalogue. The deviations are confirmed by the results obtained from ground-based photometry. Five stars show reduced metallicity, two stars are He-stro...

  12. Galaxy Rotation and Rapid Supermassive Binary Coalescence

    Science.gov (United States)

    Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-01

    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.

  13. Visual Binaries in the Orion Nebula Cluster

    CERN Document Server

    Reipurth, Bo; Connelley, Michael S; Bally, John

    2007-01-01

    We have carried out a major survey for visual binaries towards the Orion Nebula Cluster using HST images obtained with an H-alpha filter. Among 781 likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". About 9 binaries are likely line-of-sight associations. We find a binary fraction of 8.8%+-1.1% within the limited separation range from 67.5 to 675 AU. The field binary fraction in the same range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T Tauri associations have a factor 2.2 more binaries than the ONC. The binary separation distribution function of the ONC shows unusual structure, with a sudden steep decrease in the number of binaries as the separation increases beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries wider than 0.5" to binaries closer than 0.5" as a function of distance from the Trapezium, and find that this ratio is signifi...

  14. Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data

    Energy Technology Data Exchange (ETDEWEB)

    Batalha, Natalie M.; /San Jose State U.; Rowe, Jason F.; /NASA, Ames; Bryson, Stephen T.; /NASA, Ames; Barclay, Thomas; /NASA, Ames; Burke, Christopher J.; /NASA, Ames; Caldwell, Douglas A.; /NASA, Ames; Christiansen, Jessie L.; /NASA, Ames; Mullally, Fergal; /NASA, Ames; Thompson, Susan E.; /NASA, Ames; Brown, Timothy M.; /Las Cumbres Observ.; Dupree, Andrea K.; /Harvard-Smithsonian Ctr. Astrophys. /UC, Santa Cruz

    2012-02-01

    New transiting planet candidates are identified in sixteen months (May 2009 - September 2010) of data from the Kepler spacecraft. Nearly five thousand periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1091 viable new planet candidates, bringing the total count up to over 2,300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multiquarter photo-center offsets derived from difference image analysis which identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the new candidates. Ephemerides (transit epoch, T{sub 0}, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (R{sub P}/R{sub {star}}), reduced semi-major axis (d/R{sub {star}}), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (197% for candidates smaller than 2R{sub {circle_plus}} compared to 52% for candidates larger than 2R{sub {circle_plus}}) and those at longer orbital periods (123% for candidates outside of 50 day orbits versus 85% for candidates inside of 50 day orbits). The gains are larger than expected from increasing the observing window from thirteen months (Quarter 1 - Quarter 5) to sixteen months (Quarter 1 - Quarter 6). This demonstrates the benefit of continued development of pipeline analysis software. The fraction of all host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the Habitable Zone are forthcoming if, indeed, such planets are abundant.

  15. A First Comparison of Kepler Planet Candidates in Single and Multiple Systems

    CERN Document Server

    Latham, David W; Quinn, Samuel N; Batalha, Natalie M; Borucki, William J; Brown, Timothy M; Bryson, Stephen T; Buchhave, Lars A; Caldwell, Douglas A; Carter, Joshua A; Christiansen, Jesse L; Ciardi, David R; Cochran, William D; Dunham, Edward W; Fabrycky, Daniel C; Ford, Eric B; Gautier, Thomas N; Gilliland, Ronald L; Holman, Matthew J; Howell, Steve B; Ibrahim, Khadeejah A; Isaacson, Howard; Basri, Gibor; Furesz, Gabor; Geary, John C; Jenkins, Jon M; Koch, David G; Lissauer, Jack J; Marcy, Geoffrey W; Quintana, Elisa V; Ragozzine, Darin; Sasselov, Dimitar D; Shporer, Avi; Steffen, Jason H; Welsh, William F; Wohler, Bill

    2011-01-01

    In this letter we present an overview of the rich population of systems with multiple candidate transiting planets found in the first four months of Kepler data. The census of multiples includes 115 targets that show 2 candidate planets, 45 with 3, 8 with 4, and 1 each with 5 and 6, for a total of 170 systems with 408 candidates. When compared to the 827 systems with only one candidate, the multiples account for 17 percent of the total number of systems, and a third of all the planet candidates. We compare the characteristics of candidates found in multiples with those found in singles. False positives due to eclipsing binaries are much less common for the multiples, as expected. Singles and multiples are both dominated by planets smaller than Neptune; 69 +2/-3 percent for singles and 86 +2/-5 percent for multiples. This result, that systems with multiple transiting planets are less likely to include a transiting giant planet, suggests that close-in giant planets tend to disrupt the orbital inclinations of sm...

  16. A FIRST COMPARISON OF KEPLER PLANET CANDIDATES IN SINGLE AND MULTIPLE SYSTEMS

    International Nuclear Information System (INIS)

    In this Letter, we present an overview of the rich population of systems with multiple candidate transiting planets found in the first four months of Kepler data. The census of multiples includes 115 targets that show two candidate planets, 45 with three, eight with four, and one each with five and six, for a total of 170 systems with 408 candidates. When compared to the 827 systems with only one candidate, the multiples account for 17% of the total number of systems, and one-third of all the planet candidates. We compare the characteristics of candidates found in multiples with those found in singles. False positives due to eclipsing binaries are much less common for the multiples, as expected. Singles and multiples are both dominated by planets smaller than Neptune; 69+2-3% for singles and 86+2-5% for multiples. This result, that systems with multiple transiting planets are less likely to include a transiting giant planet, suggests that close-in giant planets tend to disrupt the orbital inclinations of small planets in flat systems, or maybe even prevent the formation of such systems in the first place.

  17. PLANETARY CANDIDATES OBSERVED BY KEPLER IV: PLANET SAMPLE FROM Q1-Q8 (22 MONTHS)

    International Nuclear Information System (INIS)

    We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ∼40% of the sample with R P ∼ 1 R ⊕ and represent ∼40% of the low equilibrium temperature (T eq < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample

  18. WISE Detection of the Galactic Low-Mass X-Ray Binaries

    CERN Document Server

    Wang, Xuebing

    2014-01-01

    We report on the results from our search for the Wide-field Infrared Survey Explorer detection of the Galactic low-mass X-ray binaries. Among 187 binaries catalogued in Liu et al. (2007), we find 13 counterparts and two candidate counterparts. For the 13 counterparts, two (4U~0614+091 and GX~339$-$4) have already been confirmed by previous studies to have a jet and one (GRS~1915+105) to have a candidate circumbinary disk, from which the detected infrared emission arose. Having collected the broad-band optical and near-infrared data in literature and constructed flux density spectra for the other 10 binaries, we identify that three (A0620$-$00, XTE J1118+480, and GX 1+4) are candidate circumbinary disk systems, four (Cen X-4, 4U 1700+24, 3A 1954+319, and Cyg X-2) had thermal emission from their companion stars, and three (Sco X-1, Her X-1, and Swift J1753.5$-$0127) are peculiar systems with the origin of their infrared emission rather uncertain. We discuss the results and WISE counterparts' brightness distribu...

  19. Evolution of binary stars in multiple-population globular clusters - II. Compact binaries

    Science.gov (United States)

    Hong, Jongsuk; Vesperini, Enrico; Sollima, Antonio; McMillan, Stephen L. W.; D'Antona, Franca; D'Ercole, Annibale

    2016-04-01

    We present the results of a survey of N-body simulations aimed at exploring the evolution of compact binaries in multiple-population globular clusters. We show that as a consequence of the initial differences in the structural properties of the first-generation (FG) and the second-generation (SG) populations and the effects of dynamical processes on binary stars, the SG binary fraction decreases more rapidly than that of the FG population. The difference between the FG and SG binary fraction is qualitatively similar to but quantitatively smaller than that found for wider binaries in our previous investigations. The evolution of the radial variation of the binary fraction is driven by the interplay between binary segregation, ionization and ejection. Ionization and ejection counteract in part the effects of mass segregation but for compact binaries the effects of segregation dominate and the inner binary fraction increases during the cluster evolution. We explore the variation of the difference between the FG and the SG binary fraction with the distance from the cluster centre and its dependence on the binary binding energy and cluster structural parameters. The difference between the binary fraction in the FG and the SG populations found in our simulations is consistent with the results of observational studies finding a smaller binary fraction in the SG population.

  20. Constraining RRc candidates using SDSS colours

    CERN Document Server

    Bányai, E; Molnár, L; Dobos, L; Szabó, R

    2016-01-01

    The light variations of first-overtone RR Lyrae stars and contact eclipsing binaries can be difficult to distinguish. The Catalina Periodic Variable Star catalog contains several misclassified objects, despite the classification efforts by Drake et al. (2014). They used metallicity and surface gravity derived from spectroscopic data (from the SDSS database) to rule out binaries. Our aim is to further constrain the catalog using SDSS colours to estimate physical parameters for stars that did not have spectroscopic data.

  1. Orbital eccentricities in primordial black holes binaries

    OpenAIRE

    Cholis, Ilias; Kovetz, Ely D.; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B.; Raccanelli, Alvise

    2016-01-01

    It was recently suggested that the merger of $\\sim30\\,M_\\odot$ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly ecce...

  2. Asteroid Systems: Binaries, Triples, and Pairs

    CERN Document Server

    Margot, Jean-Luc; Taylor, Patrick; Carry, Benoît; Jacobson, Seth

    2015-01-01

    In the past decade, the number of known binary near-Earth asteroids has more than quadrupled and the number of known large main belt asteroids with satellites has doubled. Half a dozen triple asteroids have been discovered, and the previously unrecognized populations of asteroid pairs and small main belt binaries have been identified. The current observational evidence confirms that small (20 km) binaries with small satellites are most likely created during large collisions.

  3. Relativistic Gravity and Binary Radio Pulsars

    OpenAIRE

    Kaspi, V. M.

    1999-01-01

    Following a summary of the basic principles of pulsar timing, we present a review of recent results from timing observations of relativistic binary pulsars. In particular, we summarize the status of timing observations of the much celebrated original binary pulsar PSR B1913+16, draw attention to the recent confirmation of strong evidence for geodetic precession in this system, review the recent measurement of multiple post-Keplerian binary parameters for PSR B1534+12, and describe the Parkes ...

  4. Detection of unresolved binaries with multicolor photometry

    CERN Document Server

    Chulkov, D; Malkov, O; Sichevskij, S; Krussanova, N; Mironov, A; Zakharov, A; Kniazev, A

    2016-01-01

    The principal goal of this paper is to specify conditions of detection of unresolved binaries by multicolor photometry. We have developed a method for estimating the critical distance at which an unresolved binary of given mass and age can be detected. The method is applied to the photometric system of the planned Lyra-B spaceborne experiment. We have shown that some types of unresolved binary stars can be discovered and distinguished from single stars solely by means of photometric observations.

  5. WIYN open cluster study. LX. Spectroscopic binary orbits in NGC 6819

    Energy Technology Data Exchange (ETDEWEB)

    Milliman, Katelyn E.; Mathieu, Robert D.; Gosnell, Natalie M. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street Madison, WI 53706 (United States); Geller, Aaron M. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Meibom, Søren [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Platais, Imants, E-mail: milliman@astro.wisc.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2014-08-01

    We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5 Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8000 days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1° field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV, and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10{sup 4} days to be 22% ± 3% and a tidal circularization period of 6.2{sub −1.1}{sup +1.1} days for NGC 6819.

  6. Relativistic Gravity and Binary Radio Pulsars

    CERN Document Server

    Kaspi, V M

    1999-01-01

    Following a summary of the basic principles of pulsar timing, we present a review of recent results from timing observations of relativistic binary pulsars. In particular, we summarize the status of timing observations of the much celebrated original binary pulsar PSR B1913+16, draw attention to the recent confirmation of strong evidence for geodetic precession in this system, review the recent measurement of multiple post-Keplerian binary parameters for PSR B1534+12, and describe the Parkes Multibeam survey, a major survey of the Galactic Plane which promises to discover new relativistic binary pulsar systems.

  7. Speech perception of noise with binary gains

    DEFF Research Database (Denmark)

    Wang, DeLiang; Kjems, Ulrik; Pedersen, Michael Syskind;

    2008-01-01

    For a given mixture of speech and noise, an ideal binary time-frequency mask is constructed by comparing speech energy and noise energy within local time-frequency units. It is observed that listeners achieve nearly perfect speech recognition from gated noise with binary gains prescribed by the i...... by the ideal binary mask. Only 16 filter channels and a frame rate of 100 Hz are sufficient for high intelligibility. The results show that, despite a dramatic reduction of speech information, a pattern of binary gains provides an adequate basis for speech perception....

  8. The equations for binary density and the binary stream of particles of electro conducting magnetic liquids

    International Nuclear Information System (INIS)

    In work on the basis of a method of the kinetic equations it is output the differential equations for binary density and a binary stream of particles of electro conducting magnetic liquids. These equations are the nonuniform equations of parabolic type. The solution of these equations completely feature existential behaviour of binary density and a binary stream of particles of electro conducting magnetic liquids, i.e. process of a structural relaxation. (author)

  9. 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

  10. 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

  11. Constraining the shape distribution and binary fractions of asteroids observed by NEOWISE

    Science.gov (United States)

    Sonnett, Sarah M.; Mainzer, Amy; Grav, Tommy; Masiero, Joseph; Bauer, James; Vernazza, Pierre; Ries, Judit Gyorgyey; Kramer, Emily

    2015-11-01

    Knowing the shape distribution of an asteroid population gives clues to its collisional and dynamical history. Constraining light curve amplitudes (brightness variations) offers a first-order approximation to the shape distribution, provided all asteroids in the distribution were subject to the same observing biases. Asteroids observed by the NEOWISE space mission at roughly the same heliocentric distances have essentially the same observing biases and can therefore be inter-compared. We used the archival NEOWISE photometry of a statistically significant sample of Jovian Trojans, Hildas, and Main belt asteroids to compare the amplitude (and by proxy, shape) distributions of L4 vs. L5 Trojans, Trojans vs. Hildas of the same size range, and several subpopulations of Main belt asteroids.For asteroids with near-fluid rubble pile structures, very large light curve amplitudes can only be explained by close or contact binary systems, offering the potential to catalog and characterize binaries within a population and gleaning more information on its dynamical evolution. Because the structure of most asteroids is not known to a high confidence level, objects with very high light curve amplitudes can only be considered candidate binaries. In Sonnett et al. (2015), we identified several binary candidates in the Jovian Trojan and Hilda populations. We have since been conducting a follow-up campaign to obtain densely sampled light curves of the binary candidates to allow detailed shape and binary modeling, helping identify true binaries. Here, we present preliminary results from the follow-up campaign, including rotation properties.This research was carried out at the Jet Propulsion Laboratory (JPL), California Institute of Technology (CalTech) under a contract with the National Aeronautics and Space Administration (NASA) and was supported by the NASA Postdoctoral Program at JPL. We make use of data products from the Wide-field Infrared Survey Explorer, which is a joint project

  12. A millisecond pulsar candidate in a 21-hr orbit: 3FGL J0212.1+5320

    CERN Document Server

    Linares, Manuel; Rodríguez-Gil, Pablo; Shahbaz, Tariq; Casares, Jorge; Fariña, Cecilia; Karjalainen, Raine

    2016-01-01

    We present the discovery of a variable optical counterpart to the unidentified gamma-ray source 3FGL J0212.1+5320, and argue this is a new compact binary millisecond pulsar (MSP) candidate. We show 3FGL J0212.1+5320 hosts a semi-detached binary with a 0.86955$\\pm$0.00015 d orbital period and a F6-type companion star at an estimated distance of D=1.1$\\pm$0.2 kpc, with a radial velocity curve semi-amplitude K$_2$=214.1$\\pm$5.0 km s$^{-1}$ and a projected rotational velocity of Vsin(i)=73.2$\\pm$1.6 km s$^{-1}$. We find a hard X-ray source at the same location with a 0.5$-$10 keV luminosity L$_\\mathrm{X}$=2.6$\\times$10$^{32}$ (D/1.1 kpc)$^2$ erg s$^{-1}$, which strengthens the MSP identification. Our results imply a mass ratio q=M$_2$/M$_1$=0.26$^{+0.02}_{-0.03}$ if the companion star fills its Roche lobe, and q$\\gtrsim$0.23 in any case. This classifies 3FGL J0212.1+5320 as a "redback" binary MSP; if its MSP nature is confirmed, this will be the brightest compact binary MSP in the optical band (r'$\\simeq$14.3 mag...

  13. R144 : a very massive binary likely ejected from R136 through a binary-binary encounter

    CERN Document Server

    Oh, Seungkyung; Banerjee, Sambaran

    2013-01-01

    R144 is a recently confirmed very massive, spectroscopic binary which appears isolated from the core of the massive young star cluster R136. The dynamical ejection hypothesis as an origin for its location is claimed improbable by Sana et al. due to its binary nature and high mass. We demonstrate here by means of direct N-body calculations that a very massive binary system can be readily dynamically ejected from a R136-like cluster, through a close encounter with a very massive system. One out of four N-body cluster models produces a dynamically ejected very massive binary system with a mass comparable to R144. The system has a system mass of $\\approx$ 355 Msun and is located at 36.8 pc from the centre of its parent cluster, moving away from the cluster with a velocity of 57 km/s at 2 Myr as a result of a binary-binary interaction. This implies that R144 could have been ejected from R136 through a strong encounter with an other massive binary or single star. In addition, we discuss all massive binaries and sin...

  14. An Efficient Approach for Candidate Set Generation

    OpenAIRE

    Nawar Malhis; Arden Ruttan; Hazem H. Refai

    2005-01-01

    When Apriori was first introduced as an algorithm for discovering association rules in a database of market basket data, the problem of generating the candidate set of the large set was a bottleneck in Apriori's performance, both in space and computational requirements. At first, many unsuccessful attempts were made to improve the generation of a candidate set. Later, other algorithms that out performed Apriori were developed that generate association rules without using a candidate set. They...

  15. Cardiac evaluation of liver transplant candidates

    OpenAIRE

    Mandell, Mercedes Susan; Lindenfeld, JoAnn; Tsou, Mei-Yung; Zimmerman, Michael

    2008-01-01

    Physicians previously thought that heart disease was rare in patients with end stage liver disease. However, recent evidence shows that the prevalence of ischemic heart disease and cardiomyopathy is increased in transplant candidates compared to most other surgical candidates. Investigators estimate that up to 26% of all liver transplant candidates have at least one critical coronary artery stenosis and that at least half of these patients will die perioperatively of cardiac complications. Ca...

  16. Millisecond Pulsars in Close Binaries

    CERN Document Server

    Tauris, Thomas M

    2015-01-01

    In this Habilitationsschrift (Habilitation thesis) I present my research carried out over the last four years at the Argelander Institute for Astronomy (AIfA) and the Max Planck Institute for Radio Astronomy (MPIfR). The thesis summarizes my main findings and has been written to fulfill the requirements for the Habilitation qualification at the University of Bonn. Although my work is mainly focused on the topic of millisecond pulsars (MSPs), there is a fairly broad spread of research areas ranging from the formation of neutron stars (NSs) in various supernova (SN) events, to their evolution, for example, via accretion processes in binary and triple systems, and finally to their possible destruction in merger events. The thesis is organized in the following manner: A general introduction to neutron stars and millisecond pulsars is given in Chapter 1. A selection of key papers published in 2011-2014 are presented in Chapters 2-10, ordered within five main research areas (ultra-stripped SNe in close binaries, ma...

  17. Discovery of a broad iron line in the black hole candidate Swift J1753.5-0127, and the disc emission in the low/hard state revisited

    NARCIS (Netherlands)

    Hiemstra, Beike; Soleri, Paolo; Mendez, Mariano; Belloni, Tomaso; Mostafa, Reham; Wijnands, Rudy

    2009-01-01

    We analysed simultaneous archival XMM-Newton and Rossi X-ray Timing Explorer observations of the X-ray binary and black hole candidate Swift J1753.5-0127. In a previous analysis of the same data, a soft thermal component was found in the X-ray spectrum, and the presence of an accretion disc extendin

  18. CONSTRAINING SUB-PARSEC BINARY SUPERMASSIVE BLACK HOLES IN QUASARS WITH MULTI-EPOCH SPECTROSCOPY. I. THE GENERAL QUASAR POPULATION

    International Nuclear Information System (INIS)

    We perform a systematic search for sub-parsec binary supermassive black holes (BHs) in normal broad-line quasars at z BLR, where RBLR ∼ 0.01-0.1 pc is the BLR size. We search for the expected line-of-sight acceleration of the broad-line velocity from binary orbital motion by cross-correlating SDSS spectra from two epochs separated by up to several years in the quasar rest frame. Out of ∼700 pairs of spectra for which we have good measurements of the velocity shift between two epochs (1σ error ∼40 km s–1), we detect 28 systems with significant velocity shifts in broad Hβ, among which 7 are the best candidates for the hypothesized binaries, 4 are most likely due to broad-line variability in single BHs, and the rest are ambiguous. Continued spectroscopic observations of these candidates will easily strengthen or disprove these claims. We use the distribution of the observed accelerations (mostly non-detections) to place constraints on the abundance of such binary systems among the general quasar population. Excess variance in the velocity shift is inferred for observations separated by longer than 0.4 yr (quasar rest frame). Attributing all the excess to binary motion would imply that most of the quasars in this sample must be in binaries, that the inactive BH must be on average more massive than the active one, and that the binary separation is at most a few times the size of the BLR. However, if this excess variance is partly or largely due to long-term broad-line variability, the requirement of a large population of close binaries is much weakened or even disfavored for massive companions. Future time-domain spectroscopic surveys of normal quasars can provide vital prior information on the structure function of stochastic velocity shifts induced by broad-line variability in single BHs. Such surveys with improved spectral quality, increased time baseline, and more epochs can greatly improve the statistical constraints of this method on the general binary

  19. Resolved Companions of Cepheids: Testing the Candidates with X-Ray Observations

    Science.gov (United States)

    Evans, Nancy Remage; Pillitteri, Ignazio; Wolk, Scott; Karovska, Margarita; Tingle, Evan; Guinan, Edward; Engle, Scott; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.

    2016-04-01

    We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥5″) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposures were set to detect essentially all companions hotter than spectral type M0 (corresponding to 0.5 M⊙). The large majority of our candidate companions were not detected in X-rays, and hence are not confirmed as young companions. One resolved candidate (S Nor #4) was unambiguously detected, but the Cepheid is a member of a populous cluster. For this reason, it is likely that S Nor #4 is a cluster member rather than a gravitationally bound companion. Two further Cepheids (S Mus and R Cru) have X-ray emission that might be produced by either the Cepheid or the candidate resolved companion. A subsequent Chandra observation of S Mus shows that the X-rays are at the location of the Cepheid/spectroscopic binary. R Cru and also V659 Cen (also X-ray bright) have possible companions closer than 5″ (the limit for this study) which are the likely sources of X-rays. One final X-ray detection (V473 Lyr) has no known optical companion, so the prime suspect is the Cepheid itself. It is a unique Cepheid with a variable amplitude. The 14 stars that we observed with XMM constitute 36% of the 39 Cepheids found to have candidate companions in our HST/WFC3 optical survey. No young probable binary companions were found with separations of ≥5″ or 4000 au. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).

  20. New systemic radial velocities of suspected RR Lyrae binary stars

    Science.gov (United States)

    Guggenberger, E.; Barnes, T. G.; Kolenberg, K.

    2016-05-01

    Among the tens of thousands of known RR Lyrae stars there are only a handful that show indications of possible binarity. The question why this is the case is still unsolved, and has recently sparked several studies dedicated to the search for additional RR Lyraes in binary systems. Such systems are particularly valuable because they might allow to constrain the stellar mass. Most of the recent studies, however, are based on photometry by finding a light time effect in the timings of maximum light. This approach is a very promising and successful one, but it has a major drawback: by itself, it cannot serve as a definite proof of binarity, because other phenomena such as the Blazhko effect or intrinsic period changes could lead to similar results. Spectroscopic radial velocity measurements, on the other hand, can serve as definite proof of binarity. We have therefore started a project to study spectroscopically RR Lyrae stars that are suspected to be binaries. We have obtained radial velocity (RV) curves with the 2.1m telescope at McDonald observatory. From these we derive systemic RVs which we will compare to previous measurements in order to find changes induced by orbital motions. We also construct templates of the RV curves that can facilitate future studies. We also observed the most promising RR Lyrae binary candidate, TU UMa, as no recent spectroscopic measurements were available. We present a densely covered pulsational RV curve, which will be used to test the predictions of the orbit models that are based on the O - C variations.

  1. A PSF-based approach to Kepler/K2 data. II. Exoplanet candidates in Praesepe (M 44)

    Science.gov (United States)

    Libralato, M.; Nardiello, D.; Bedin, L. R.; Borsato, L.; Granata, V.; Malavolta, L.; Piotto, G.; Ochner, P.; Cunial, A.; Nascimbeni, V.

    2016-08-01

    In this work we keep pushing K2 data to a high photometric precision, close to that of the Kepler main mission, using a PSF-based, neighbour-subtraction technique, which also overcome the dilution effects in crowded environments. We analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5, and extract light curves of stars imaged on module 14, where most of the cluster lies. We present two candidate exoplanets hosted by cluster members and five by field stars. As a by-product of our investigation, we find 1680 eclipsing binaries and variable stars, 1071 of which are new discoveries. Among them, we report the presence of a heartbeat binary star. Together with this work, we release to the community a catalogue with the variable stars and the candidate exoplanets found, as well as all our raw and detrended light curves.

  2. A PSF-based approach to Kepler/K2 data. II. Exoplanet candidates in Praesepe (M 44)

    CERN Document Server

    Libralato, M; Bedin, L R; Borsato, L; Granata, V; Malavolta, L; Piotto, G; Ochner, P; Cunial, A; Nascimbeni, V

    2016-01-01

    In this work we keep pushing K2 data to a high photometric precision, close to that of the Kepler main mission, using a PSF-based, neighbour-subtraction technique, which also overcome the dilution effects in crowded environments. We analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5, and extract light curves of stars imaged on module 14, where most of the cluster lies. We present two candidate exoplanets hosted by cluster members and five by field stars. As a by-product of our investigation, we find 1680 eclipsing binaries and variable stars, 1071 of which are new discoveries. Among them, we report the presence of a heartbeat binary star. Together with this work, we release to the community a catalogue with the variable stars and the candidate exoplanets found, as well as all our raw and detrended light curves.

  3. Design of lead-free candidate alloys for high-temperature soldering based on the Au–Sn system

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hattel, Jesper Henri; Hald, John

    2010-01-01

    Au–Sn based candidate alloys have been proposed as a substitute for high-lead content solders that are currently being used for high-temperature soldering. The changes in microstructure and microhardness associated with the alloying of Ag and Cu to the Au rich side as well to the Sn rich side of...... the Au–Sn binary system were explored in this work. Furthermore, the effects of thermal aging on the microstructure and microhardness of these promising Au–Sn based ternary alloys were investigated. For this purpose, the candidate alloys were aged at a lower temperature, 150°C for up to 1week and...

  4. Unsupervised learning of binary vectors: A Gaussian scenario

    International Nuclear Information System (INIS)

    We study a model of unsupervised learning where the real-valued data vectors are isotropically distributed, except for a single symmetry-breaking binary direction B(set-membership sign){-1,+1}N, onto which the projections have a Gaussian distribution. We show that a candidate vector J undergoing Gibbs learning in this discrete space, approaches the perfect match J=B exponentially. In addition to the second-order ''retarded learning'' phase transition for unbiased distributions, we show that first-order transitions can also occur. Extending the known result that the center of mass of the Gibbs ensemble has Bayes-optimal performance, we show that taking the sign of the components of this vector (clipping) leads to the vector with optimal performance in the binary space. These upper bounds are shown generally not to be saturated with the technique of transforming the components of a special continuous vector, except in asymptotic limits and in a special linear case. Simulations are presented which are in excellent agreement with the theoretical results. (c) 2000 The American Physical Society

  5. A solar twin in the eclipsing binary LL Aqr

    CERN Document Server

    Graczyk, D; Pavlovski, K; Southworth, J; Pietrzynski, G; Maxted, P F L; Konorski, P; Gieren, W; Pilecki, B; Taormina, M; Suchomska, K; Karczmarek, P; Gorski, M; Wielgorski, P

    2016-01-01

    In the course of a project to study eclipsing binary stars in vinicity of the Sun, we found that the cooler component of LL Aqr is a solar twin candidate. This is the first known star with properties of a solar twin existing in a non-interacting eclipsing binary, offering an excellent opportunity to fully characterise its physical properties with very high precision. We used extensive multi-band, archival photometry and the Super-WASP project and high-resolution spectroscopy obtained from the HARPS and CORALIE spectrographs. The spectra of both components were decomposed and a detailed LTE abundance analysis was performed. The light and radial velocity curves were simultanously analysed with the Wilson-Devinney code. The resulting highly precise stellar parameters were used for a detailed comparison with PARSEC, MESA, and GARSTEC stellar evolution models. LL Aqr consists of two main-sequence stars (F9 V + G3 V) with masses of M1 = 1.1949$\\pm$0.0007 and M2=1.0337$\\pm$0.0007 $M_\\odot$, radii R1 = 1.321$\\pm$0.00...

  6. The PTF Orion Project: Eclipsing Binaries and Young Stellar Objects

    CERN Document Server

    van Eyken, Julian C; Rebull, Luisa M; Stauffer, John R; Akeson, Rachel L; Beichman, Charles A; Boden, Andrew F; von Braun, Kaspar; Gelino, Dawn M; Hoard, D W; Howell, Steve B; Kane, Stephen R; Plavchan, Peter; Ramírez, Solange V; Bloom, Joshua S; Cenko, S Bradley; Kasliwal, Mansi M; Kulkarni, Shrinivas R; Law, Nicholas M; Nugent, Peter E; Ofek, Eran O; Poznanski, Dovi; Quimby, Robert M; Grillmair, Carl J; Laher, Russ; Levitan, David; Mattingly, Sean; Surace, Jason A

    2011-01-01

    The Palomar Transient Factory (PTF) Orion project is an experiment within the broader PTF survey, a systematic automated exploration of the sky for optical transients. Taking advantage of the wide field of view available using the PTF camera at the Palomar 48" telescope, 40 nights were dedicated in December 2009-January 2010 to perform continuous high-cadence differential photometry on a single field containing the young (7-10Myr) 25 Ori association. The primary motivation for the project is to search for planets around young stars in this region. The unique data set also provides for much ancillary science. In this first paper we describe the survey and data reduction pipeline, and present initial results from an inspection of the most clearly varying stars relating to two of the ancillary science objectives: detection of eclipsing binaries and young stellar objects. We find 82 new eclipsing binary systems, 9 of which we are candidate 25 Ori- or Orion OB1a-association members. Of these, 2 are potential young...

  7. Evidence for a binary origin of a central compact object

    Science.gov (United States)

    Doroshenko, Victor; Pühlhofer, Gerd; Kavanagh, Patrick; Santangelo, Andrea; Suleimanov, Valery; Klochkov, Dmitry

    2016-05-01

    Central compact objects (CCOs) are thought to be young thermally emitting isolated neutron stars that were born during the preceding core-collapse supernova explosion. Here, we present evidence that at least in one case the CCO could have been formed within a binary system. We show that the highly reddened optical source IRAS 17287-3443, located 25 arcsec away from the CCO candidate XMMUJ173203.3-344518 and classified previously as a post asymptotic giant branch star, is indeed surrounded by a dust shell. This shell is heated by the central star to temperatures of ˜90 K and observed as extended infrared emission in 8-160 μm band. The dust temperature also increases in the vicinity of the CCO which implies that it likely resides within the shell. We estimate the total dust mass to be ˜0.4-1.5 M⊙ which significantly exceeds expected dust yields by normal stars and thus likely condensed from supernova ejecta. Taking into account that both the age of the supernova remnant and the duration of active mass-loss phase by the optical star are much shorter than the total lifetime of either object, the supernova and the onset of the active mass-loss phase of the companion have likely occurred approximately simultaneously. This is most easily explained if the evolution of both objects is interconnected. We conclude, therefore, that both stars were likely members of the same binary system disrupted by a supernova.

  8. {\\Delta}{\\mu} Binaries among Stars with Large Proper Motions

    CERN Document Server

    Khovritchev, M Yu

    2016-01-01

    Based on observations performed with the Pulkovo normal astrograph in 2008-2015 and data from sky surveys (DSS, 2MASS, SDSS DR12, WISE), we have investigated the motions of 1308 stars with proper motions larger than 300 mas/yr down to magnitude 17. The main idea of our search for binary stars based on this material is reduced to comparing the quasi-mean (POSS2-POSS1; an epoch difference of $\\approx$50 yr) and quasi-instantaneous (2MASS, SDSS, WISE, Pulkovo; an epoch difference of $\\approx$10 yr) proper motions. If the difference is statistically significant compared to the proper motion errors, then the object may be considered as a {\\Delta}{\\mu}-binary candidate. One hundred and twenty one stars from among those included in the observational program satisfy this requirement. Additional confirmations of binarity for a number of stars have been obtained by comparing the calculated proper motions with the data from several programs of stellar trigonometric parallax determinations and by analyzing the asymmetry ...

  9. Fast large-scale object retrieval with binary quantization

    Science.gov (United States)

    Zhou, Shifu; Zeng, Dan; Shen, Wei; Zhang, Zhijiang; Tian, Qi

    2015-11-01

    The objective of large-scale object retrieval systems is to search for images that contain the target object in an image database. Where state-of-the-art approaches rely on global image representations to conduct searches, we consider many boxes per image as candidates to search locally in a picture. In this paper, a feature quantization algorithm called binary quantization is proposed. In binary quantization, a scale-invariant feature transform (SIFT) feature is quantized into a descriptive and discriminative bit-vector, which allows itself to adapt to the classic inverted file structure for box indexing. The inverted file, which stores the bit-vector and box ID where the SIFT feature is located inside, is compact and can be loaded into the main memory for efficient box indexing. We evaluate our approach on available object retrieval datasets. Experimental results demonstrate that the proposed approach is fast and achieves excellent search quality. Therefore, the proposed approach is an improvement over state-of-the-art approaches for object retrieval.

  10. Pulsating Components in Binary and Multiple Stellar Systems --- A Catalog of Oscillating Binaries

    OpenAIRE

    Zhou, A. -Y.

    2010-01-01

    We present an up-to-date catalog of pulsating binaries, i.e. the binary and multiple stellar systems containing pulsating components, along with a statistics on them. Compared to the earlier compilation by Soydugan et al.(2006a) of 25 delta Scuti-type `oscillating Algol-type eclipsing binaries' (oEA), the recent collection of 74 oEA by Liakos et al.(2012), and the collection of Cepheids in binaries by Szabados (2003a), the numbers and types of pulsating variables in binaries are now extended....

  11. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Yungelson, Lev R.

    2006-12-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA. Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

  12. The Evolution of Compact Binary Star Systems

    Directory of Open Access Journals (Sweden)

    Konstantin A. Postnov

    2014-05-01

    Full Text Available We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs, neutron stars (NSs, and black holes (BHs. Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  13. Eliciting Subjective Probabilities with Binary Lotteries

    DEFF Research Database (Denmark)

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

    We evaluate the binary lottery procedure for inducing risk neutral behavior in a subjective belief elicitation task. Harrison, Martínez-Correa and Swarthout [2013] found that the binary lottery procedure works robustly to induce risk neutrality when subjects are given one risk task defined over o...

  14. Pulsed Accretion onto Eccentric and Circular Binaries

    CERN Document Server

    Muñoz, Diego J

    2016-01-01

    We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is the first set of simulations to tackle the problem of binary accretion using a finite-volume scheme on a freely moving mesh, which allows for accurate measurements of accretion onto individual stars for arbitrary binary eccentricity. While accretion onto a circular binary shows bursts with period of ~5 times the binary period P_b,accretion onto an eccentric binary is predominantly modulated at the period ~1P_b. For an equal-mass circular binary, the accretion rates onto individual stars are quite similar to each other, following the same variable pattern in time. By contrast, for eccentric binaries, one of the stars can accrete at a rate 10-20 times larger than its companion. This "symmetry breaking" between the stars, however, alternates over timescales of order 200 P_b, and can be attributed to a slowly precessing, eccentric circumbinary disk. Over longer timescales, the ...

  15. ECCENTRIC EVOLUTION OF SUPERMASSIVE BLACK HOLE BINARIES

    International Nuclear Information System (INIS)

    In recent numerical simulations, it has been found that the eccentricity of supermassive black hole (SMBH)-intermediate black hole (IMBH) binaries grows toward unity through interactions with the stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to a value well below the Hubble time. It also gives a theoretical explanation of the existence of eccentric binaries such as that in OJ287. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of the scattering experiment between SMBH binaries and field stars indicated that the eccentricity dose not change significantly. This discrepancy leaves the high eccentricity of the SMBH binaries in N-body simulations unexplained. Here, we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with a large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under a non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the 'last-parsec problem'.

  16. Gravitational radiation, inspiraling binaries, and cosmology

    Science.gov (United States)

    Chernoff, David F.; Finn, Lee S.

    1993-01-01

    We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.

  17. Bayesian analysis of exoplanet and binary orbits

    CERN Document Server

    Schulze-Hartung, Tim; Henning, Thomas

    2012-01-01

    We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection and characterisation tool), a novel program for the combined or separate Bayesian analysis of astrometric and radial-velocity measurements of potential exoplanet hosts and binary stars. The capabilities of BASE are demonstrated using all publicly available data of the binary Mizar A.

  18. An Extremely Fast Halo Hot Subdwarf Star in a Wide Binary System

    Science.gov (United States)

    Németh, Péter; Ziegerer, Eva; Irrgang, Andreas; Geier, Stephan; Fürst, Felix; Kupfer, Thomas; Heber, Ulrich

    2016-04-01

    New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 (V = 17.92 mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute luminosities are consistent with the same distance, confirming the physical nature of the binary, which is the first double-lined hyper-velocity candidate. Our spectral decomposition of the Keck/ESI spectrum provided an sdB+K3V pair, analogous to many long-period subdwarf binaries observed in the Galactic disk. We found the subdwarf atmospheric parameters: {T}{{eff}}=30\\600+/- 500 K, {log}g=5.57+/- 0.06 cm s-2, and He abundance {log}(n{{He}}/n{{H}})=-3.0+/- 0.2. Oxygen is the most abundant metal in the hot subdwarf atmosphere, and Mg and Na lines are the most prominent spectral features of the cool companion, consistent with a metallicity of [{{Fe}}/{{H}}]=-1.3. The non-detection of radial velocity variations suggest the orbital period to be a few hundred days, in agreement with similar binaries observed in the disk. Using the SDSS-III flux calibrated spectrum we measured the distance to the system d=5.5+/- 0.5 {{kpc}}, which is consistent with ultraviolet, optical, and infrared photometric constraints derived from binary spectral energy distributions. Our kinematic study shows that the Galactic rest-frame velocity of the system is so high that an unbound orbit cannot be ruled out. On the other hand, a bound orbit requires a massive dark matter halo. We conclude that the binary either formed in the halo or was accreted from the tidal debris of a dwarf galaxy by the Milky Way.

  19. An Extremely Fast Halo Hot Subdwarf Star in a Wide Binary System

    Science.gov (United States)

    Németh, Péter; Ziegerer, Eva; Irrgang, Andreas; Geier, Stephan; Fürst, Felix; Kupfer, Thomas; Heber, Ulrich

    2016-04-01

    New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 (V = 17.92 mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute luminosities are consistent with the same distance, confirming the physical nature of the binary, which is the first double-lined hyper-velocity candidate. Our spectral decomposition of the Keck/ESI spectrum provided an sdB+K3V pair, analogous to many long-period subdwarf binaries observed in the Galactic disk. We found the subdwarf atmospheric parameters: {T}{{eff}}=30\\600+/- 500 K, {log}g=5.57+/- 0.06 cm s‑2, and He abundance {log}(n{{He}}/n{{H}})=-3.0+/- 0.2. Oxygen is the most abundant metal in the hot subdwarf atmosphere, and Mg and Na lines are the most prominent spectral features of the cool companion, consistent with a metallicity of [{{Fe}}/{{H}}]=-1.3. The non-detection of radial velocity variations suggest the orbital period to be a few hundred days, in agreement with similar binaries observed in the disk. Using the SDSS-III flux calibrated spectrum we measured the distance to the system d=5.5+/- 0.5 {{kpc}}, which is consistent with ultraviolet, optical, and infrared photometric constraints derived from binary spectral energy distributions. Our kinematic study shows that the Galactic rest-frame velocity of the system is so high that an unbound orbit cannot be ruled out. On the other hand, a bound orbit requires a massive dark matter halo. We conclude that the binary either formed in the halo or was accreted from the tidal debris of a dwarf galaxy by the Milky Way.

  20. Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data

    CERN Document Server

    Batalha, Natalie M; Bryson, Stephen T; Barclay, Thomas; Burke, Christopher J; Caldwell, Douglas A; Christiansen, Jessie L; Mullally, Fergal; Thompson, Susan E; Brown, Timothy M; Dupree, Andrea K; Fabrycky, Daniel C; Ford, Eric B; Fortney, Jonathan J; Gilliland, Ronald L; Isaacson, Howard; Latham, David W; Marcy, Geoffrey W; Quinn, Samuel; Ragozzine, Darin; Shporer, Avi; Borucki, William J; Ciardi, David R; Gautier, Thomas N; Haas, Michael R; Jenkins, Jon M; Koch, David G; Lissauer, Jack J; Rapin, William; Basri, Gibor S; Boss, Alan P; Buchhave, Lars A; Charbonneau, David; Christensen-Dalsgaard, Joergen; Clarke, Bruce D; Cochran, William D; Demory, Brice-Olivier; Devore, Edna; Esquerdo, Gilbert A; Everett, Mark; Fressin, Francois; Geary, John C; Girouard, Forrest R; Gould, Alan; Hall, Jennifer R; Holman, Matthew J; Howard, Andrew W; Howell, Steve B; Ibrahim, Khadeejah A; Kinemuchi, K; Kjeldsen, Hans; Klaus, Todd C; Li, Jie; Lucas, Philip W; Morris, Robert L; Prsa, Andrej; Quintana, Elisa; Sanderfer, Dwight T; Sasselov, Dimitar; Seader, Shawn E; Smith, Jeffrey C; Steffen, Jason H; Still, Martin; Stumpe, Martin C; Tarter, Jill C; Tenenbaum, Peter; Torres, Guillermo; Twicken, Joseph D; Uddin, Kamal; Van Cleve, Jeffrey; Walkowicz, Lucianne; Welsh, William F

    2012-01-01

    New transiting planet candidates are identified in sixteen months (May 2009 - September 2010) of data from the Kepler spacecraft. Nearly five thousand periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1,091 viable new planet candidates, bringing the total count up to over 2,300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis which identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the new candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (197% for candidates smaller than 2Re com...

  1. Planet Scattering Around Binaries: Ejections, Not Collisions

    CERN Document Server

    Smullen, Rachel A; Shannon, Andrew

    2016-01-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically effects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Asid...

  2. Orbital dynamics of binary boson star systems

    International Nuclear Information System (INIS)

    We extend our previous studies of head-on collisions of boson stars by considering orbiting binary boson stars. We concentrate on equal-mass binaries and study the dynamical behavior of boson/boson and boson/antiboson pairs. We examine the gravitational wave output of these binaries and compare with other compact binaries. Such a comparison lets us probe the apparent simplicity observed in gravitational waves produced by black hole binary systems. In our system of interest however, there is an additional internal freedom which plays a significant role in the system's dynamics, namely, the phase of each star. Our evolutions show rather simple behavior at early times, but large differences occur at late times for the various initial configurations

  3. Logistic chaotic maps for binary numbers generations

    International Nuclear Information System (INIS)

    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.

  4. Special Education Teacher Candidate Assessment: A Review

    Science.gov (United States)

    McCall, Zach; McHatton, Patricia Alvarez; Shealey, Monika Williams

    2014-01-01

    Teacher preparation has been under intense scrutiny in recent years. In order for preparation of special education teacher candidates to remain viable, candidate assessment practices must apply practices identified in the extant literature base, while special education teacher education researchers must extend this base with rigorous efforts to…

  5. Do People 'Like' Candidates on Facebook?

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Kleis

    The online popularity of a few exceptional candidates has led many to suggest that social media have given politicians powerful ways of communicating directly with voters. In this paper, we examine whether this is happening on a significant scale and show, based on analysis of 224 candidates invo...

  6. Binary Cepheids from optical interferometry

    CERN Document Server

    Gallenne, A; Mérand, A; Monnier, J D; Pietrzyński, J Breitfelder G; Gieren, W

    2013-01-01

    Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical laboratories, providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. When in binary systems, we can investigate the age and evolution of the Cepheid, estimate the mass and distance, and constrain theoretical models. However, most of the companions are located too close to the Cepheid (1-40 mas) to be spatially resolved with a 10-meter class telescope. The only way to spatially resolve such systems is to use long-baseline interferometry. Recently, we have started a unique and long-term interferometric program that aims at detecting and characterizing physical parameters of the Cepheid companions, with as main objectives the determination of accurate masses and geometric distances.

  7. Binary theory of electronic stopping

    CERN Document Server

    Sigmund, P

    2002-01-01

    Binary stopping theory has been developed to characterize the electronic stopping of swift heavy ions in matter. It is an extension of Bohr's classical theory of 1913 incorporating screening, higher-order-Z sub 1 and shell corrections, high-speed quantum and relativity corrections as well as projectile excitation and ionization. The main numerical input comes from optical properties. The computation of shell corrections involves orbital velocity distributions of target and projectile electrons. Calculated stopping parameters depend on ion charge. Equilibrium stopping forces may be computed by adoption of a suitable model for the equilibrium charge state. This paper summarizes the current status of the theory, in particular the sensitivity of its predictions to pertinent input. Charge-dependent stopping forces have been calculated for selected systems and compared to experimental results. Equilibrium stopping forces calculated for a wide variety of ion-target combinations are compared with experimental data fr...

  8. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  9. Planetary Candidates Observed by Kepler IV: Planet Sample from Q1-Q8 (22 Months)

    OpenAIRE

    Burke, Christopher J.; Christensen, Jessie L.; Ciardi, David R.; Morton, Timothy D.; Shporer, Avi

    2014-01-01

    We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during tra...

  10. Improved mixed integer optimization approach for data rectification with gross error candidates%带显著误差集的改进MILP数据协调方法

    Institute of Scientific and Technical Information of China (English)

    李笕列; 荣冈

    2009-01-01

    Mixed integer linear programming(MILP)approach for simultaneous gross error detection and data reconciliation has been proved as an efficient Way to adjust process data with material,energy,and other balance constrains.BUt the efficiency will decrease significantly when this method IS applied in a large-scale problem because there are too many binary variables involved.In this article, an improved method IS proposed in order to generate gross error candidates with reliability factors before data rectification.Candidates are used in the MILP objectivc function to improve the emciency and accuracy by reducing the number of binary variables and gwmg accurate weights for suspected gross errors candidates.Performance of this improved method IS compared and discussed by applying the algorithm in a widely used industrial example.

  11. THE PALOMAR TRANSIENT FACTORY ORION PROJECT: ECLIPSING BINARIES AND YOUNG STELLAR OBJECTS

    International Nuclear Information System (INIS)

    The Palomar Transient Factory (PTF) Orion project is one of the experiments within the broader PTF survey, a systematic automated exploration of the sky for optical transients. Taking advantage of the wide (3.05 x 2.03) field of view available using the PTF camera installed at the Palomar 48 inch telescope, 40 nights were dedicated in 2009 December to 2010 January to perform continuous high-cadence differential photometry on a single field containing the young (7-10 Myr) 25 Ori association. Little is known empirically about the formation of planets at these young ages, and the primary motivation for the project is to search for planets around young stars in this region. The unique data set also provides for much ancillary science. In this first paper, we describe the survey and the data reduction pipeline, and present some initial results from an inspection of the most clearly varying stars relating to two of the ancillary science objectives: detection of eclipsing binaries and young stellar objects. We find 82 new eclipsing binary systems, 9 of which are good candidate 25 Ori or Orion OB1a association members. Of these, two are potential young W UMa type systems. We report on the possible low-mass (M-dwarf primary) eclipsing systems in the sample, which include six of the candidate young systems. Forty-five of the binary systems are close (mainly contact) systems, and one of these shows an orbital period among the shortest known for W UMa binaries, at 0.2156509 ± 0.0000071 days, with flat-bottomed primary eclipses, and a derived distance that appears consistent with membership in the general Orion association. One of the candidate young systems presents an unusual light curve, perhaps representing a semi-detached binary system with an inflated low-mass primary or a star with a warped disk, and may represent an additional young Orion member. Finally, we identify 14 probable new classical T-Tauri stars in our data, along with one previously known (CVSO 35) and one

  12. Gamma-ray binaries and related systems

    CERN Document Server

    Dubus, Guillaume

    2013-01-01

    After initial claims and a long hiatus, it is now established that several binary stars emit high (0.1-100 GeV) and very high energy (>100 GeV) gamma rays. A new class has emerged called 'gamma-ray binaries', since most of their radiated power is emitted beyond 1 MeV. Accreting X-ray binaries, novae and a colliding wind binary (eta Car) have also been detected - 'related systems' that confirm the ubiquity of particle acceleration in astrophysical sources. Do these systems have anything in common ? What drives their high-energy emission ? How do the processes involved compare to those in other sources of gamma rays: pulsars, active galactic nuclei, supernova remnants ? I review the wealth of observational and theoretical work that have followed these detections, with an emphasis on gamma-ray binaries. I present the current evidence that gamma-ray binaries are driven by rotation-powered pulsars. Binaries are laboratories giving access to different vantage points or physical conditions on a regular timescale as ...

  13. Interrupted Binary Mass Transfer in Star Clusters

    CERN Document Server

    Leigh, Nathan W C; Toonen, Silvia

    2016-01-01

    Binary mass transfer is at the forefront of some of the most exciting puzzles of modern astrophysics, including Type Ia supernovae, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this time-scale to the mean time for stable mass transfer to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing mass transfer that are expected to be disrupted as a function of the host cluster pro...

  14. A fast search strategy for gravitational waves from low-mass X-ray binaries

    CERN Document Server

    Messenger, C

    2007-01-01

    We present a new type of search strategy designed specifically to find continuously emitting gravitational wave sources in known binary systems based on the incoherent sum of frequency modulated binary signal sidebands. The search pipeline can be divided into three stages: the first is a wide bandwidth, F-statistic search demodulated for sky position. This is followed by a fast second stage in which areas in frequency space are identified as signal candidates through the frequency domain convolution of the F-statistic with an approximate signal template. For this second stage only precise information on the orbit period and approximate information on the orbital semi-major axis are required apriori. For the final stage we propose a fully coherent Markov chain monte carlo based follow up search on the frequency subspace defined by the candidates identified by the second stage. This search is particularly suited to the low-mass X-ray binaries, for which orbital period and sky position are typically well known a...

  15. How the Sausage is Made: Kepler's False Alarms, False Positives, and Planet Candidates

    Science.gov (United States)

    Coughlin, J.

    2014-04-01

    The Kepler mission has now designated over 7,000 Kepler objects of interest (KOIs), or transit-like signatures, utilizing up to four years of data. The number of potentially habitable planet candidates (PCs) among this sample has risen significantly over time. However, starting with Kepler threshold crossing events (TCEs), there are initially about as many false alarms (FAs) detected as there are KOIs. Furthermore, due to its design, contamination from eclipsing binaries, variable stars, and other transiting planets result in a significant number of KOIs being designated as false positives (FPs). Many of these FAs and FPs occur at long orbital periods, where habitable planets are typically found. I will review the process of how an initial TCE becomes a KOI, and then is ultimately classified as a FA, FP, or PC, along with the various vetting tools employed. The understanding of this process is crucial to performing accurate statistical analyses on populations of habitable planet candidates discovered by Kepler.

  16. Pd-Si binary bulk metallic glass

    Institute of Scientific and Technical Information of China (English)

    YAO KeFu; CHEN Na

    2008-01-01

    Pd80+xSi20-x (x=0, 1, and 2) binary metallic glasses with the diameter ranging from 7 to 8 mm were prepared by a combination of fluxing and water quenching or air cooling. Thermal analysis results show that with increasing Si content, the glass transition temperature Tg, the initial crystallization temperature Tx and the onset crystalliza-tion temperature Tp of Pd-Si binary glassy alloys increase. Moreover, the super-cooled liquid region reaches 61 K. It indicates that Pd-Si binary alloys possess large glass forming ability, which can be greatly improved by fluxing treatment.

  17. Pd-Si binary bulk metallic glass

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pd80+xSi20-x (x=0,1,and 2) binary metallic glasses with the diameter ranging from 7 to 8 mm were prepared by a combination of fluxing and water quenching or air cooling. Thermal analysis results show that with increasing Si content,the glass transition temperature Tg,the initial crystallization temperature Tx and the onset crystalliza-tion temperature Tp of Pd-Si binary glassy alloys increase. Moreover,the super-cooled liquid region reaches 61 K. It indicates that Pd-Si binary alloys possess large glass forming ability,which can be greatly improved by fluxing treatment.

  18. Eliciting Subjective Probabilities with Binary Lotteries

    DEFF Research Database (Denmark)

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

    2014-01-01

    We evaluate a binary lottery procedure for inducing risk neutral behavior in a subjective belief elicitation task. Prior research has shown this procedure to robustly induce risk neutrality when subjects are given a single risk task defined over objective probabilities. Drawing a sample from the...... same subject population, we find evidence that the binary lottery procedure also 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 of subjective probabilities in subjects with...

  19. Cassini states for black hole binaries

    OpenAIRE

    Correia, Alexandre C. M.

    2015-01-01

    Cassini states correspond to the equilibria of the spin axis of a body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black hole binary systems base...

  20. Fast algorithms for generating binary holograms

    CERN Document Server

    Stuart, Dustin; Kuhn, Axel

    2014-01-01

    We describe three algorithms for generating binary-valued holograms. Our methods are optimised for producing large arrays of tightly focussed optical tweezers for trapping particles. Binary-valued holograms allow us to use a digital mirror device (DMD) as the display element, which is much faster than other alternatives. We describe how our binary amplitude holograms can be used to correct for phase errors caused by optical aberrations. Furthermore, we compare the speed and accuracy of the algorithms for both periodic and arbitrary arrangements of traps, which allows one to choose the ideal scheme depending on the circumstances.

  1. Eclipsing binary stars in the Large Magellanic Cloud: results from the EROS-2, OGLE and VMC surveys

    Science.gov (United States)

    Muraveva, T.; Clementini, G.; Maceroni, C.; Evans, C. J.; Moretti, M. I.; Cioni, M.-R. L.; Marquette, J. B.; Ripepi, V.; de Grijs, R.; Groenewegen, M. A. T.; Piatti, A. E.; van Loon, J. Th.

    2014-09-01

    We present a catalogue of 1768 eclipsing binary stars (EBs) detected in the Large Magellanic Cloud (LMC) by the second generation of the EROS survey (hereinafter EROS-2); 493 of them are new discoveries located in outer regions (out of the central bar) of the LMC. These sources were originally included in a list of candidate classical Cepheids (CCs) extracted from the EROS-2 catalogue on the basis of the period (0.89 < 17.82 mag] diagram. After visual inspection of the light curves we reclassified them as eclipsing binaries. They have blue colours (BEROS - REROS < 0.2 mag) hence we classed them as hot eclipsing binaries (HEBs) containing hot massive components: main sequence (MS) stars or blue giants. We present Ks-band light curves for 999 binaries from our sample that have a counterpart in the VISTA near-infrared ESO public survey of the Magellanic Clouds system (VMC). We provide spectral classifications of 13 HEBs with existing spectroscopy. We divided our sample into contact-like binaries and detached/semi-detached systems based on both visual inspection and the parameters of the Fourier decomposition of the light curves and analysed the period-luminosity (PL) relations of the contact-like systems using the REROS and Ks magnitudes at maximum light. The contact-like binaries in our sample do not follow PL relations. We analysed the sample of contact binaries from the OGLE III catalogue and confirmed that PLI and PL_{K_s} sequences are defined only by eclipsing binaries containing a red giant component.

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

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. H$\\alpha$ Emission From Active Equal-mass, Wide M Dwarf Binaries

    CERN Document Server

    Gunning, Heather C; Davenport, James R A; Dhital, Saurav; Hawley, Suzanne L; West, Andrew A

    2014-01-01

    We identify a sample of near-equal mass wide binary M dwarf systems from the SLoWPoKES catalog of common proper-motion binaries and obtain follow-up observations of their chromospheric activity as measured by the H$\\alpha$ emission line. We present optical spectra for both components of 48 candidate M dwarf binaries, confirming their mid-M spectral types. Of those 48 coeval pairs, we find eight with H$\\alpha$ emission from both components, three with weak emission in one component and no emission in the other, and 37 with two inactive components. We find that of the eleven pairs with at least one active component, only three follow the net trend of decreasing activity strength $L_{\\rm H\\alpha}/L_{\\rm bol}$ with later spectral type. The difference in quiescent activity strength between the A and B components is larger than what would be expected based on the small differences in color (mass). For five binaries with two active components, we present 47 hours of time-resolved spectroscopy, observed on the ARC 3....

  5. Testing Asteroseismology with red giants in eclipsing binary and multiple-star systems

    CERN Document Server

    Gaulme, Patrick

    2013-01-01

    Red-giant stars are proving to be an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions CoRoT and Kepler as well as recent theoretical advances. Eclipsing binaries are also fundamental astrophysical objects, and when coupled with asteroseismology, they would provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. Gaulme et al. (2013) reported the discovery of 13 bona fide candidates (12 previously unknown) to be eclipsing binaries, one to be an non-eclipsing binary with tidally induced oscillations, and 10 more to be hierarchical triple systems, all of which include a pulsating red giant. When ground-based support in terms of atmospheric abundance and radial velocities are completed, these red giants in eclipsing binary systems have the potential to become some of the m...

  6. A massive binary black-hole system in OJ 287 and a test of general relativity.

    Science.gov (United States)

    Valtonen, M J; Lehto, H J; Nilsson, K; Heidt, J; Takalo, L O; Sillanpää, A; Villforth, C; Kidger, M; Poyner, G; Pursimo, T; Zola, S; Wu, J-H; Zhou, X; Sadakane, K; Drozdz, M; Koziel, D; Marchev, D; Ogloza, W; Porowski, C; Siwak, M; Stachowski, G; Winiarski, M; Hentunen, V-P; Nissinen, M; Liakos, A; Dogru, S

    2008-04-17

    Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later. PMID:18421348

  7. Compact Binaries in Star Clusters I - Black Hole Binaries Inside Globular Clusters

    OpenAIRE

    Downing, J. M. B.; Benacquista, M. J.; Giersz, M.; Spurzem, R.

    2009-01-01

    We study the compact binary population in star clusters, focusing on binaries containing black holes, using a self-consistent Monte Carlo treatment of dynamics and full stellar evolution. We find that the black holes experience strong mass segregation and become centrally concentrated. In the core the black holes interact strongly with each other and black hole-black hole binaries are formed very efficiently. The strong interactions, however, also destroy or eject the black hole-black hole bi...

  8. Properties of planets in binary systems. The role of binary separation

    OpenAIRE

    Desidera, S.; Barbieri, M.

    2006-01-01

    The statistical properties of planets in binaries were investigated. Any difference to planets orbiting single stars can shed light on the formation and evolution of planetary systems. As planets were found around components of binaries with very different separation and mass ratio, it is particularly important to study the characteristics of planets as a function of the effective gravitational influence of the companion. A compilation of planets in binary systems was made; a search for compa...

  9. Wide Low-Mass Tertiary Companions of Binary Star Systems as a Test of Star Formation Theories

    Science.gov (United States)

    Douglas, Stephanie; Allen, P.

    2012-01-01

    We will present the status of a common proper motion search for wide low-mass stellar and sub-stellar companions to known white dwarf-M dwarf binary systems. I-band observations were made using the 31" NURO telescope at Lowell Observatory. Candidate companions are selected using astrometry from our own data and 2MASS photometry. We have begun to spectroscopically confirm candidates that pass our selection criteria. The ultimate goal of the search is to test star formation theories which predict that close binary systems form by transferring angular momentum to a third companion. To this end, we will model the physical companion population and perform Bayesian statistical analysis to determine the best-fit population model to our data. Here we will present our spectroscopically confirmed companions as well as the preliminary results of our population models and statistical analysis.

  10. A systematic search for close supermassive black hole binaries in the Catalina Real-Time Transient Survey

    CERN Document Server

    Graham, Matthew J; Stern, Daniel; Drake, Andrew J; Mahabal, Ashish A; Donalek, Ciro; Glikman, Eilat; Larsen, Steve; Christensen, Eric

    2015-01-01

    Hierarchical assembly models predict a population of supermassive black hole (SMBH) binaries. These are not resolvable by direct imaging but may be detectable via periodic variability (or nanohertz frequency gravitational waves). Following our detection of a 5.2 year periodic signal in the quasar PG 1302-102 (Graham et al. 2015), we present a novel analysis of the optical variability of 243,500 known spectroscopically confirmed quasars using data from the Catalina Real-time Transient Survey (CRTS) to look for close (< 0.1 pc) SMBH systems. Looking for a strong Keplerian periodic signal with at least 1.5 cycles over a baseline of nine years, we find a sample of 111 candidate objects. This is in conservative agreement with theoretical predictions from models of binary SMBH populations. Simulated data sets, assuming stochastic variability, also produce no equivalent candidates implying a low likelihood of spurious detections. The periodicity seen is likely attributable to either jet precession, warped accreti...

  11. The first low-mass black hole X-ray binary identified in quiescence outside of a globular cluster

    OpenAIRE

    Tetarenko, B. E.; Bahramian, A.; Arnason, R. M.; Miller-Jones, J. C. A.; Repetto, S.; Heinke, C. O.; Maccarone, T. J.; Chomiuk, L.; Sivakoff, G. R.; Strader, J.; Kirsten, F.; Vlemmings, W

    2016-01-01

    The observed relation between the X-ray and radio properties of low-luminosity accreting black holes has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters. Here we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al. 2014, as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a 2.2$^{+0.5}_{-0.3}$ kpc distance, which identifie...

  12. Binaries in the Hipparcos data: Keep digging

    CERN Document Server

    Pourbaix, D; Jorissen, A

    2004-01-01

    Among the 120 000 objects in the Hipparcos catalogue, only 235 were fitted with an orbital model. Besides these 235 original astrometric binaries, most Hipparcos entries with a known spectroscopic orbit (extrasolar planet or stellar companion) have now been re-processed, as part of the on-going construction of the 9th Catalogue of Spectroscopic Binary Orbits (SB9, available at http://sb9.astro.ulb.ac.be). The pitfalls and successes of this re-processing are discussed in various contexts, like (i) orbital inclinations: the holy grail for extrasolar planets (ii) searching for binaries without a priori knowledge of their spectroscopic orbital elements, and application to barium stars (iii) why not all SB9 entries yield acceptable astrometric solutions? The lessons learned from this study are useful to devise the best possible binary-detection and orbit-determination algorithms for future astrometric missions like GAIA.

  13. A mesoscopic model for binary fluids

    CERN Document Server

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

    2016-01-01

    We propose a model to study symmetric binary fluids, based in the mesoscopic molecular simulation technique known as multiparticle collision, where space and state variables are continuous while time is discrete. We include a repulsion rule to simulate segregation processes that does not require the calculation of the interaction forces between particles, thus allowing the description of binary fluids at a mesoscopic scale. The model is conceptually simple, computationally efficient, maintains Galilean invariance, and conserves the mass and the energy in the system at micro and macro scales; while 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 density profile, width of the interface, phase separation and phase growth. We also apply the model to study binary fluids in crowded environments with consistent results.

  14. Cattle Candidate Genes for Milk Production Traits

    OpenAIRE

    Kadlec,Tomáš

    2012-01-01

    The aim of this thesis is to make an overview of important candidate genes affecting milk yield and milk quality parameters, with an emphasis on genes associated with the quantity and quality of milk proteins and milk fat.

  15. Evaluating historical candidate genes for schizophrenia

    DEFF Research Database (Denmark)

    Farrell, M S; Werge, T; Sklar, P;

    2015-01-01

    Prior to the genome-wide association era, candidate gene studies were a major approach in schizophrenia genetics. In this invited review, we consider the current status of 25 historical candidate genes for schizophrenia (for example, COMT, DISC1, DTNBP1 and NRG1). The initial study for 24 of these...... genes explicitly evaluated common variant hypotheses about schizophrenia. Our evaluation included a meta-analysis of the candidate gene literature, incorporation of the results of the largest genomic study yet published for schizophrenia, ratings from informed researchers who have published on these...... genes, and ratings from 24 schizophrenia geneticists. On the basis of current empirical evidence and mostly consensual assessments of informed opinion, it appears that the historical candidate gene literature did not yield clear insights into the genetic basis of schizophrenia. A likely reason why...

  16. Scattering Properties of Candidate Planetary Regolith Materials

    Science.gov (United States)

    Nelson, R. M.; Smythe, W. D.; Hapke, B. W.; Hale, A. S.; Piatek, J. A.

    2001-01-01

    The laboratory investigation of the scattering properties of candidate planetary regolith materials is an important technique for understanding the physical properties of a planetary regolith. Additional information is contained in the original extended abstract.

  17. Characterization of nanoparticles as candidate reference materials

    International Nuclear Information System (INIS)

    We report the characterization of three different nanoparticles (silica, silver and multi-walled carbon nanotubes) as candidate reference material. We focus our analysis on the size distribution of those particles as measured by different microscopy techniques. (author)

  18. Characterization of nanoparticles as candidate reference materials

    Energy Technology Data Exchange (ETDEWEB)

    Martins Ferreira, E.H.; Robertis, E. de; Landi, S.M.; Gouvea, C.P.; Archanjo, B.S.; Almeida, C.A.; Araujo, J.R. de; Kuznetsov, O.; Achete, C.A., E-mail: smlandi@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    We report the characterization of three different nanoparticles (silica, silver and multi-walled carbon nanotubes) as candidate reference material. We focus our analysis on the size distribution of those particles as measured by different microscopy techniques. (author)

  19. 76 FR 4896 - Call for Candidates

    Science.gov (United States)

    2011-01-27

    ... accepted accounting principles for federal government entities. Generally, non-federal Board members are... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Call for Candidates AGENCY: Federal Accounting Standards Advisory Board. ACTION:...

  20. 76 FR 36130 - Call for Candidates

    Science.gov (United States)

    2011-06-21

    ... establish generally accepted accounting principles for federal government entities. Generally, non- federal... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Call for Candidates AGENCY: Federal Accounting Standards Advisory Board. ACTION: Request...

  1. Evolution of Binary Stars in Multiple-Population Globular Clusters - II. Compact Binaries

    CERN Document Server

    Hong, Jongsuk; Sollima, Antonio; McMillan, Stephen L W; D'Antona, Franca; D'Ercole, Annibale

    2016-01-01

    We present the results of a survey of N-body simulations aimed at exploring the evolution of compact binaries in multiple-population globular clusters.We show that as a consequence of the initial differences in the structural properties of the first-generation (FG) and the second-generation (SG) populations and the effects of dynamical processes on binary stars, the SG binary fraction decreases more rapidly than that of the FG population. The difference between the FG and SG binary fraction is qualitatively similar to but quantitatively smaller than that found for wider binaries in our previous investigations.The evolution of the radial variation of the binary fraction is driven by the interplay between binary segregation, ionization and ejection. Ionization and ejection counteract in part the effects of mass segregation but for compact binaries the effects of segregation dominate and the inner binary fraction increases during the cluster evolution. We explore the variation of the difference between the FG an...

  2. Tidal capture formation of Low Mass X-Ray Binaries from wide binaries in the field

    CERN Document Server

    Michaely, Erez

    2015-01-01

    We present a potentially efficient dynamical formation scenario for Low Mass X-ray Binaries (LMXBs) in the field, focusing on black-hole (BH) LMXBs. In this formation channel LMXBs are formed from wide binaries $(>1000$ AU) with a BH component and a stellar companion. The wide binary is perturbed by fly-by's of field stars and its orbit random-walks and changes over time. This diffusion process can drive the binary into a sufficiently eccentric orbit such that the binary components tidally interact at peri-center and the binary evolves to become a short period binary, which eventually evolves into an LMXB. The formation rate of LMXBs through this channel mostly depends on the number of such BH wide binaries progenitors, which in turn depends on the velocity kicks imparted to BHs (or NSs) at birth. We consider several models for the formation and survival of such wide binaries, and calculate the LMXB formation rates for each model. We find that models where BHs form through direct collapse with no/little natal...

  3. Binary is Good: A Binary Inference Framework for Primary User Separation in Cognitive Radio Networks

    CERN Document Server

    Nguyen, Huy; Han, Zhu

    2010-01-01

    Primary users (PU) separation concerns with the issues of distinguishing and characterizing primary users in cognitive radio (CR) networks. We argue the need for PU separation in the context of collaborative spectrum sensing and monitor selection. In this paper, we model the observations of monitors as boolean OR mixtures of underlying binary latency sources for PUs, and devise a novel binary inference algorithm for PU separation. Simulation results show that without prior knowledge regarding PUs' activities, the algorithm achieves high inference accuracy. An interesting implication of the proposed algorithm is the ability to effectively represent n independent binary sources via (correlated) binary vectors of logarithmic length.

  4. A statistical study of binary and multiple clusters in the LMC

    CERN Document Server

    Dieball, A; Grebel, E K; Dieball, Andrea; Mueller, Hardo; Grebel, Eva K.

    2002-01-01

    Based on the Bica et al. (1999) catalogue we studied the star cluster system of the LMC and provide a new catalogue of all binary and multiple cluster candidates found. We performed Monte Carlo simulations and produced artificial cluster distributions that we compared with the real one in order to check how many of the found cluster pairs and groups can be expected statistically due to chance superposition on the plane of the sky. We found that, depending on the cluster density, between 56% (bar region) and 12% (outer LMC) of the detected pairs can be explained statistically. We studied in detail the properties of the multiple cluster candidates. The binary cluster candidates seem to show a tendency to form with components of similar size. When possible, we studied the age structure of the cluster groups and found that the multiple clusters are predominantly young with only a few cluster groups older than 300 Myr. The spatial distribution of the cluster pairs and groups coincides with the distribution of clus...

  5. 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.

  6. Structure of simple (binary) oxides

    International Nuclear Information System (INIS)

    Crystal structures of different simple and binary oxides of M3O, M2O, MO, MO2, MO4, MO3, M2O3, M3O4, M2O5, M2O7 composition as well as lowest cesium oxides (Cs7O, Cs4O, Cs11O3) are considered. Cs3O crystals are constructed out of the colomns of the Cs3O composition consisting of octahedrals OCs6 jointed through the opposite faces. This is the ZrI3 ''antistructure''. Cs2O has the CdCl2 antistructure. ZrO2, HfO2, CeO2, ThO2, UO2, NpO2, PuO2, AmO2, CmO2, PoO2 oxides have the structural type of fluorite of rutile - VO2, NbO2, TaO2, MoO2, ReO2 oxides, of wurtzite - BeO. The NbO oxide is unique, in its structure the oxygen and niobium atoms form four complanar bonds. A three-dimensional skeleton constructed out of the octahedral structural units Nb6 (Nb-Nb 2.98 A) is separated. ZrO2 is a polymorphous, at 1100 grad. the monoclinic modification transfers to tetragonal. M2O7 oxides are Re2O7, Tc2O7

  7. Vaccine candidates for malaria: what's new?

    Science.gov (United States)

    Takashima, Eizo; Morita, Masayuki; Tsuboi, Takafumi

    2016-01-01

    Although it is more than a decade since the parasite genome information was obtained, standardized novel genome-wide selection/prioritization strategies for candidacy of malaria vaccine antigens are still sought. In the quest to systematically identify candidates, it is impossible to overemphasize the usefulness of wheat germ cell-free technology in expressing quality proteins for the post-genome vaccine candidate discovery. PMID:26559316

  8. Detecting Eccentric Globular Cluster Binaries with LISA

    OpenAIRE

    Benacquista, M.

    2001-01-01

    The energy carried in the gravitational wave signal from an eccentric binary is spread across several harmonics of the orbital frequency. The inclusion of the harmonics in the analysis of the gravitational wave signal increases the signal-to-noise ratio of the detected signal for binaries whose fundamental frequency is below the galactic confusion-limited noise cut-off. This can allow for an improved angular resolution for sources whose orbital period is greater than 2000 s. Globular cluster ...

  9. Copula-based bivariate binary response models

    OpenAIRE

    Winkelmann, Rainer

    2009-01-01

    The bivariate probit model is frequently used for estimating the effect of an endogenous binary regressor on a binary outcome variable. This paper discusses simple modifications that maintain the probit assumption for the marginal distributions while introducing non-normal dependence among the two variables using copulas. Simulation results and evidence from two applications, one on the effect of insurance status on ambulatory expenditure and one on the effect of completing high school on sub...

  10. Planet Scattering Around Binaries: Ejections, Not Collisions

    OpenAIRE

    Smullen, Rachel A.; Kratter, Kaitlin M.; Shannon, Andrew

    2016-01-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in...

  11. GAIA survey of galactic eclipsing binaries

    OpenAIRE

    Zwitter, Tomaz

    2002-01-01

    General importance and capabilities of observations of eclipsing binaries by the forthcoming ESA mission GAIA are discussed. Availability of spectroscopic observations and a large number of photometric bands on board will make it possible to reliably determine physical parameters for $\\sim 10^5$ binary stars. It is stressed that current methods of object by object analysis will have to be modified and included in an automatic analysis pipeline.

  12. Formation of Compact Binaries in Globular Clusters

    OpenAIRE

    Rappaport, Saul; Pfahl, Eric; Rasio, Fred; Podsiadlowski, Philipp

    2001-01-01

    We report here on two complementary population synthesis studies which relate directly to the formation and evolution of neutron star binaries in globular clusters. In the first, we compute the probability of retaining neutron stars in globular clusters, and quantitatively confirm the idea that the retention fraction for neutron stars born in binary systems is greatly enhanced over those born in isolated stars. However, the retention fraction may well be insufficient to explain the current po...

  13. Diffusion in ordered binary solid systems

    International Nuclear Information System (INIS)

    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.)

  14. Binary nature of the Barium stars

    International Nuclear Information System (INIS)

    We present radial-velocity spectrometer observations that indicate that Ba II stars are binary systems. The secondary stars of these systems have low masses, consistent with their being degenerate objects which have lost mass onto their primaries in a previous stage of evolution. It is suggested that the Population II equivalents, the CH stars, may also be binary systems. This may be related to the fact that they are found only in globular clusters of the lowest central concentration

  15. On homogeneous nontransitive binary perfect code

    OpenAIRE

    Mogilnykh, I. Yu.; Solov'eva, F. I.

    2014-01-01

    Studying binary perfect codes we show the existence of homogeneous nontransitive codes. Thus, as far as perfect codes are concerned, the propelinear codes are strictly contained in transitive codes, wheresas homogeneous codes form a strict subclass of transitive codes. In the work we deduce a necessary and sufficient condition for transitivity of perfect binary codes of rank one more than that of Hamming code. The paper is in Russian.

  16. Planetary Candidates Observed by Kepler IV: Planet Sample From Q1-Q8 (22 Months)

    CERN Document Server

    Burke, Christopher J; Mullally, F; Rowe, Jason F; Christiansen, Jessie L; Thompson, Susan E; Coughlin, Jeffrey L; Haas, Michael R; Batalha, Natalie M; Caldwell, Douglas A; Jenkins, Jon M; Still, Martin; Barclay, Thomas; Borucki, William J; Chaplin, William J; Ciardi, David R; Clarke, Bruce D; Cochran, William D; Demory, Brice-Olivier; Esquerdo, Gilbert A; Gautier, Thomas N; Gilliland, Ronald L; Girouard, Forrest R; Havel, Mathieu; Henze, Christopher E; Howell, Steve B; Huber, Daniel; Latham, David W; Li, Jie; Morehead, Robert C; Morton, Timothy D; Pepper, Joshua; Quintana, Elisa; Ragozzine, Darin; Seader, Shawn E; Shah, Yash; Shporer, Avi; Tenenbaum, Peter; Twicken, Joseph D; Wolfgang, Angie

    2013-01-01

    We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 Threshold Crossing Events (TCEs), 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOI) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2,738 Kepler planet candidates distributed across 2,017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ~40% of th...

  17. Vetting Kepler Planet Candidates in the Sub-Jovian Desert with Multi-Band Photometry

    CERN Document Server

    Colón, Knicole D; Ford, Eric B

    2015-01-01

    We present new multi-band transit photometry of three small (R$_{p}$ < 6 R$_{\\oplus}$), short-period (P < 6 days) Kepler planet candidates acquired with the Gran Telescopio Canarias. These observations supplement the results presented in Col\\'on & Ford (2011) and Col\\'on et al. (2012), where we used multicolor transit photometry of five Kepler planet candidates to search for wavelength-dependent transit depths and either validate planet candidates or identify eclipsing binary false positives within our sample. In those previous studies, we provided evidence that three targets were false positives and two targets were planets. Here, we present observations that provide evidence supporting a planetary nature for KOI 439.01 and KOI 732.01, and we find that KOI 531.01, a 6 R$_{\\oplus}$ planet candidate around an M dwarf, is likely a false positive. We also present a discussion of the purported "sub-Jovian desert" in the orbital period-planet radius plane, which cannot be easily explained by observationa...

  18. Search for gravitational waves from galactic and extra--galactic binary neutron stars

    CERN Document Server

    Abbott, B; Adhikari, R; Ageev, A; Allen, B; Amin, R; Anderson, S B; Anderson, W G; Araya, M; Armandula, H; Ashley, M; Asiri, F; Aufmuth, P; Aulbert, C; Babak, S; Balasubramanian, R; Ballmer, S; Barish, B C; Barker, C; Barker, D; Barnes, M; Barr, B; Barton, M A; Bayer, K; Beausoleil, R; Belczynski, K; Bennett, R; Berukoff, S J; Betzwieser, J; Bhawal, B; Bilenko, I A; Billingsley, G; Black, E; Blackburn, K; Blackburn, L; Bland, B; Bochner, B; Bogue, L; Bork, R; Bose, S; Brady, P R; Braginsky, V B; Brau, J E; Brown, D A; Bullington, A; Bunkowski, A; Buonanno, A; Burgess, R; Busby, D; Butler, W E; Byer, R L; Cadonati, L; Cagnoli, G; Camp, J B; Cantley, C A; Cardenas, L; Carter, K; Casey, M M; Castiglione, J; Chandler, A; Chapsky, J; Charlton, P; Chatterji, S; Chelkowski, S; Chen, Y; Chickarmane, V; Chin, D; Christensen, N; Churches, D; Cokelaer, T; Colacino, C; Coldwell, R; Coles, M; Cook, D; Corbitt, T; Coyne, D; Creighton, J D E; Creighton, T D; Crooks, D R M; Csatorday, P; Cusack, B J; Cutler, C; D'Ambrosio, E; Danzmann, K; Daw, E; De Bra, D; DeSalvo, R; Delker, T; Dergachev, V; Dhurandhar, S V; Di Credico, A; Ding, H; Drever, R W P; Dupuis, R J; Edlund, J A; Ehrens, P; Elliffe, E J; Etzel, T; Evans, M; Evans, T; Fairhurst, S; Fallnich, C; Farnham, D; Fejer, M M; Findley, T; Fine, M; Finn, L S; Franzen, K Y; Freise, A; Frey, R; Fritschel, P; Frolov, V V; Fyffe, M; Ganezer, K S; Garofoli, J; Giaime, J A; Gillespie, A; Goda, K; Goler, S; González, G; Grandclément, P; Grant, A; Gray, C; Gretarsson, A M; Grimmett, D; Grote, H; Grünewald, S; Gustafson, E; Gustafson, R; Günther, M; Hamilton, W O; Hammond, M; Hanson, J; Hardham, C; Harms, J; Harry, G; Hartunian, A; Heefner, J; Hefetz, Y; Heinzel, G; Heng, I S; Hennessy, M; Hepler, N; Heptonstall, A; Heurs, M; Hewitson, M; Hild, S; Hindman, N; Hoang, P; Hough, J; Hrynevych, M; Hua, W; Ito, M; Itoh, Y; Ivanov, A; Jennrich, O; Johnson, B; Johnson, W W; Johnston, W R; Jones, D I; Jones, L; Jungwirth, D; Kalogera, V; Katsavounidis, E; Kawabe, K; Kawamura, S; Kells, W; Kern, J; Khan, A; Killbourn, S; Killow, C J; Kim, C; King, C; King, P; Klimenko, S; Koranda, S; Kotter, K; Kovalik, Yu; Kozak, D; Krishnan, B; Landry, M; Langdale, J; Lantz, B; Lawrence, R; Lazzarini, A; Lei, M; Leonor, I; Libbrecht, K; Libson, A; Lindquist, P; Liu, S; Logan, J; Lormand, M; Lubinski, M; Luck, H; Lyons, T T; MacInnis, M; Machenschalk, B; Mageswaran, M; Mailand, K; Majid, W; Malec, M; Mann, F; Marin, A; Marka, S; Maros, E; Mason, J; Mason, K; Matherny, O; Matone, L; Mavalvala, N; McCarthy, R; McClelland, D E; McHugh, M; McNabb, J W C; Mendell, G; Mercer, R A; Meshkov, S; Messaritaki, E; Messenger, C; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miyakawa, O; Miyoki, S; Mohanty, S; Moreno, G; Mossavi, K; Mukherjee, S; Murray, P; Myers, J; Müller, G; Nagano, S; Nash, T; Nayak, R; Newton, G; Nocera, F; Noel, J S; Nutzman, P; O'Reilly, B; Olson, T; Ottaway, D J; Ottewill, A; Ouimette, D A; Overmier, H; Owen, B J; Pan, Y; Papa, M A; Parameshwaraiah, V; Parameswariah, C; Pedraza, M; Penn, S; Pitkin, M; Plissi, M; Prix, R; Quetschke, V; Raab, F; Radkins, H; Rahkola, R; Rakhmanov, M; Rao, S R; Rawlins, K; Ray-Majumder, S; Re, V; Redding, D; Regehr, M W; Regimbau, T; Reid, S; Reilly, K T; Reithmaier, K; Reitze, D H; Richman, S; Riesen, R; Riles, K; Rivera, B; Rizzi, A; Robertson, D I; Robertson, N A; Robison, L; Roddy, S; Rollins, J; Romano, J D; Romie, J; Rong, H; Rose, D; Rotthoff, E; Rowan, S; Russell, P; Ryan, K; Rüdiger, A; Salzman, I; Sandberg, V; Sanders, G H; Sannibale, V; Sathyaprakash, B; Saulson, P R; Savage, R; Sazonov, A; Schilling, R; Schlaufman, K; Schmidt, V; Schnabel, R; Schofield, R; Schutz, B F; Schwinberg, P; Scott, S M; Seader, S E; Searle, A C; Sears, B; Seel, S; Seifert, F; Sengupta, A S; Shapiro, C A; Shawhan, P; Shoemaker, D H; Shu, Q Z; Sibley, A; Siemens, X; Sievers, L; Sigg, D; Sintes, A M; Smith, J R; Smith, M; Smith, M R; Sneddon, P H; Spero, R; Stapfer, G; Steussy, D; Strain, K A; Strom, D; Stuver, A; Summerscales, T; Sumner, M C; Sutton, P J; Sylvestre, J; Takamori, A; Tanner, D B; Tariq, H; Taylor, I; Taylor, R; Thorne, K A; Thorne, K S; Tibbits, M; Tilav, S; Tinto, M; Tokmakov, K V; Torres, C; Torrie, C; Traylor, G; Tyler, W; Ugolini, D W; Ungarelli, C; Vallisneri, M; Van Putten, M H P M; Vass, S; Vecchio, A; Veitch, J; Vorvick, C; Vyachanin, S P; Wallace, L; Walther, H; Ward, H; Ware, B; Watts, K; Webber, D; Weidner, A; Weiland, U; Weinstein, A; Weiss, R; Welling, H; Wen, L; Wen, S; Whelan, J T; Whitcomb, S E; Whiting, B F; Wiley, S; Wilkinson, C; Willems, P A; Williams, P R; Williams, R; Willke, B; Wilson, A; Winjum, B J; Winkler, W; Wise, S; Wiseman, A G; Woan, G; Wooley, R; Worden, J; Wu, W; Yakushin, I; Yamamoto, H; Yoshida, S; Zaleski, K D; Zanolin, M; Zawischa, I; Zhang, L; Zhu, R; Zotov, N P; Zucker, M; Zweizig, J

    2005-01-01

    We use 373 hours ($\\approx$ 15 days) of data from the second science run of the LIGO gravitational-wave detectors to search for signals from binary neutron star coalescences within a maximum distance of about 1.5 Mpc, a volume of space which includes the Andromeda Galaxy and other galaxies of the Local Group of galaxies. This analysis requires a signal to be found in data from detectors at the two LIGO sites, according to a set of coincidence criteria. The background (accidental coincidence rate) is determined from the data and is used to judge the significance of event candidates. No inspiral gravitational wave events were identified in our search. Using a population model which includes the Local Group, we establish an upper limit of less than 47 inspiral events per year per Milky Way equivalent galaxy with 90% confidence for non-spinning binary neutron star systems with component masses between 1 and 3 $M_\\odot$.

  19. Discovery of very high energy gamma-rays associated with an X-ray binary

    CERN Document Server

    Aharonian, F; Aye, K M; Bazer-Bachi, A R; Beilicke, M; Benbow, W; Berge, D; Berghaus, P; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Breitling, F; Brown, A M; Bussons-Gordo, J; Chadwick, P M; Chounet, L M; Cornils, R; Costamante, L; Degrange, B; Dickinson, H J; Djannati-Ata, A; O'Connor-Drury, L; Dubus, G; Emmanoulopoulos, D; Espigat, P; Feinstein, F; Fleury, P; Fontaine, G; Fuchs, Y; Funk, S; Gallant, Y A; Giebels, B; Gillessen, S; Glicenstein, J F; Goret, P; Hadjichristidis, C; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hofmann, W; Holleran, M; Horns, D; Jacholkowska, A; De Jager, O C; Khelifi, B; Komin, Nu; Konopelko, A; Latham, I J; Le Gallou, R; Lemiere, A; Lemoine-Goumard, M; Leroy, N; Lohse, T; Marcowith, A; Martin, J M; Martineau-Huynh, O; Masterson, C; McComb, T J L; De Naurois, Mathieu; Nolan, S J; Noutsos, A; Orford, K J; Osborne, J L; Ouchrif, M; Panter, M; Pelletier, G; Pita, S; Pühlhofer, G; Punch, M; Raubenheimer, B C; Raue, M; Raux, J; Rayner, S M; Reimer, A; Reimer, O; Ripken, J; Rob, L; Rolland, L; Rowell, G; Sahakian, V V; Sauge, L; Schlenker, S; Schlickeiser, R; Schuster, C; Schwanke, U; Siewert, M; Sol, H; Spangler, D; Steenkamp, R; Stegmann, C; Tavernet, J P; Terrier, R; Theoret, C G; Tluczykont, M; Vasileiadis, G; Venter, C; Vincent, P; Völk, H J; Wagner, S J

    2005-01-01

    X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and X-ray observations have led to the presumption that some X-ray binaries called microquasars behave as scaled down active galactic nuclei. Microquasars have resolved radio emission that is thought to arise from a relativistic outflow akin to active galactic nuclei jets, in which particles can be accelerated to large energies. Very high energy gamma-rays produced by the interactions of these particles have been observed from several active galactic nuclei. Using the High Energy Stereoscopic System, we find evidence for gamma-ray emission >100 GeV from a candidate microquasar, LS 5039, showing that particles are also accelerated to very high energies in these systems.

  20. On the Convergence of Biogeography-Based Optimization for Binary Problems

    Directory of Open Access Journals (Sweden)

    Haiping Ma

    2014-01-01

    Full Text Available Biogeography-based optimization (BBO is an evolutionary algorithm inspired by biogeography, which is the study of the migration of species between habitats. A finite Markov chain model of BBO for binary problems was derived in earlier work, and some significant theoretical results were obtained. This paper analyzes the convergence properties of BBO on binary problems based on the previously derived BBO Markov chain model. Analysis reveals that BBO with only migration and mutation never converges to the global optimum. However, BBO with elitism, which maintains the best candidate in the population from one generation to the next, converges to the global optimum. In spite of previously published differences between genetic algorithms (GAs and BBO, this paper shows that the convergence properties of BBO are similar to those of the canonical GA. In addition, the convergence rate estimate of BBO with elitism is obtained in this paper and is confirmed by simulations for some simple representative problems.

  1. Detached Red Giant Eclipsing Binary Twins: Rosetta Stones to the Galactic Bulge

    CERN Document Server

    Nataf, David M; Pinsonneault, Marc H

    2012-01-01

    We identify 34 highly-probable detached, red giant eclipsing binary pairs among 315 candidates in Devor's catalog of $\\sim$10,000 OGLE-II eclipsing binaries. We estimate that there should be at least 200 such systems in OGLE-III. We show that spectroscopic measurements of the metallicities and radial-velocity-derived masses of these systems would independently constrain both the age-metallicity and helium-metallicity relations of the Galactic Bulge, potentially breaking the age-helium degeneracy that currently limits our ability to characterize the Bulge stellar population. Mass and metallicity measurements alone would be sufficient to immediately validate or falsify recent claims about the age and helium abundance of the Bulge. A spectroscopic survey of these systems would constrain models of Milky Way assembly, as well as provide significant auxiliary science on research questions such as mass loss on the red giant branch. We discuss the theoretical uncertainties in stellar evolution models that would need ...

  2. Computing the merger of black-hole binaries the IBBH problem

    CERN Document Server

    Brady, P R; Thorne, K S; Brady, Patrick R.; Creighton, Jolien D. E.; Thorne, Kip S.

    1998-01-01

    Gravitational radiation arising from the inspiral and merger of binary black holes (BBH's) is a promising candidate for detection by kilometer-scale interferometric gravitational wave observatories. This paper discusses a serious obstacle to searches for such radiation and to the interpretation of any observed waves: the inability of current computational techniques to evolve a BBH through its last ~10 orbits of inspiral (~100 radians of gravitational-wave phase). A new set of numerical-relativity techniques is proposed for solving this ``Intermediate Binary Black Hole'' (IBBH) problem: (i) numerical evolutions performed in coordinates co-rotating with the BBH, in which the metric coefficients evolve on the long timescale of inspiral, and (ii) techniques for mathematically freezing out gravitational degrees of freedom that are not excited by the waves.

  3. Cardiac evaluation of liver transplant candidates

    Institute of Scientific and Technical Information of China (English)

    Mercedes Susan Mandell; JoAnn Lindenfeld; Mei-Yung Tsou; Michael Zimmerman

    2008-01-01

    Physicians previously thought that heart disease was rare in patients with end stage liver disease. However, recent evidence shows that the prevalence of ischemic heart disease and cardiomyopathy is increased in transplant candidates compared to most other surgical candidates. Investigators estimate that up to 26% of all liver transplant candidates have at least one critical coronary artery stenosis and that at least half of these patients will die perioperatively of cardiac complications. Cardiomyopathy also occurs in greater frequency. While all patients with advanced cardiac disease have defects in cardiac performance, a larger than expected number of patients have classical findings of dilated, restrictive and hypertropic cardiomyopathy. This may explain why up to 56% of patients suffer from hypoxemia due to pulmonary edema following transplant surgery. There is considerable controversy on how to screen transplant candidates for the presence of heart disease. Questions focus upon, which patients should be screened and what tests should be used. This review examines screening strategies for transplant candidates and details the prognostic value of common tests used to identify ischemic heart disease. We also review the physiological consequences of cardiomyopathy in transplant candidates and explore the specific syndrome of "cirrhotic cardiomyopathy".

  4. Texture classification by texton: statistical versus binary.

    Science.gov (United States)

    Guo, Zhenhua; Zhang, Zhongcheng; Li, Xiu; Li, Qin; You, Jane

    2014-01-01

    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. PMID:24520346

  5. 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.

  6. Direct Exoplanet Detection with Binary Differential Imaging

    CERN Document Server

    Rodigas, Timothy J; Mamajek, Eric E; Males, Jared R; Close, Laird M; Morzinski, Katie; Hinz, Philip M; Kaib, Nathan

    2015-01-01

    Binaries are typically excluded from direct imaging exoplanet surveys. However, the recent findings of Kepler and radial velocity programs show that planets can and do form in binary systems. Here, we suggest that visual binaries offer unique advantages for direct imaging. We show that Binary Differential Imaging (BDI), whereby two stars are imaged simultaneously at the same wavelength within the isoplanatic patch at high Strehl ratio, offers improved point spread function (PSF) subtraction that can result in increased sensitivity to planets close to each star. We demonstrate this by observing a young visual binary separated by 4\\asec ~with MagAO/Clio-2 at 3.9 \\microns, where the Strehl ratio is high, the isoplanatic patch is large, and giant planets are bright. Comparing BDI to angular differential imaging (ADI), we find that BDI's 5$\\sigma$ contrast is \\about 0.5 mags better than ADI's within \\about 1\\asec ~for the particular binary we observed. Because planets typically reside close to their host stars, BD...

  7. Spectroscopic Orbits for Kepler FOV Eclipsing Binaries

    Science.gov (United States)

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

    2013-02-01

    We are currently involved in a four year program of precise eclipsing binary photometry with the NASA Kepler Observatory. Our goal is to search for variations in minimum light timing for intermediate mass eclipsing binaries. Such periodic variations will reveal the reflex motion caused by any distant, low mass object that orbits the close binary. it Kepler's unprecedented accuracy and continuous observations provide a unique opportunity to detect the low mass companions that are predicted to result from the angular momentum of the natal cloud. The goal of this proposal is to obtain blue spectra of short period (0.9-6d) eclipsing binaries, derive radial velocities, and produce a double-lined spectroscopic orbit (as well as estimates of the stellar effective temperatures, gravities, and metallicities). Combined with the it Kepler light curve, we will determine very accurate masses and radii for the members of the close binary, which will yield the mass-inclination product M_3 sin i for any companions detected by light travel time or other effects. An extended sample of eclipsing binaries with longer periods (up to 50d) is now being investigated to test whether the presence of a tertiary companion declines with increasing period. We propose to obtain a single spectrum at quadrature for the brightest 48 stars in this expanded sample to characterize the effective temperatures and total mass contained in these systems.

  8. Stability and Coalescence of Massive Twin Binaries

    CERN Document Server

    Hwang, Jason A; Rasio, Frederic A; Kalogera, Vassiliki

    2015-01-01

    Massive stars are usually found in binaries, and binaries with periods less than 10 days may have a preference for near equal component masses. In this paper we investigate the evolution of these binaries all the way to contact and the possibility that these systems can be progenitors of double neutron star binaries. The small orbital separations of observed double neutron star binaries suggest that the progenitor systems underwent a common envelope phase at least once during their evolution. Bethe & Brown (1998) proposed that massive binary twins will undergo a common envelope evolution while both components are ascending the red giant branch or asymptotic giant branch simultaneously, also known as double-core evolution. Using models generated from the stellar evolution code Evolve Zero Age Main Sequence, we determine the range of mass ratios resulting in both components simultaneously ascending the RGB or AGB as a function of the difference in birth times, t. We find that, even for a generous t=5 Myr, t...

  9. Spectroscopic subsystems in nearby wide binaries

    CERN Document Server

    Tokovinin, Andrei

    2015-01-01

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5-m telescope to study short-period systems. Data reduction is described, mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, for some of them orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67pc. It is found that 43 binaries contain at least one subsystem and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods match the simple prescription proposed by the author (2014, AJ, 147, 87). The remaining 53 simple wide binaries with a median projected separation of 1300AU have the distri...

  10. An Initial Census of Eclipsing Binaries in the Pleiades and Hyades in Field 4 of the K2 Mission

    Science.gov (United States)

    Stauffer, John R.; Stassun, Keivan; Aigrain, Suzanne; Hillenbrand, Lynne; David, Trevor J.; Rebull, Luisa M.; K2 Young Clusters Team

    2016-01-01

    We have identified four new eclipsing binary members of the Pleiades and Hyades in the K2 Field 4 data.For one of those stars, where radial velocities are available, we report a complete SB1/EB orbital fit to the data.For the other EB candidates, we describe the information we have derived from the K2 light curve and what is known about the stars from the published literature.

  11. Design and Implementation of BDB, the Binary Star Database

    Science.gov (United States)

    Kaygorodov, P.; Kovaleva, D.; Malkov, O.

    2013-02-01

    The Binary star DataBase (BDB, http://bdb.inasan.ru) is created to provide liasons between binary star catalogue data of various origin. Information on different observational types of binaries is obtained from heterogeneous sources of data - astronomical catalogues and surveys. The database allows a variety of query options useful for selected stars investigation purposes, for binary observations planning, and for construction and examination of binary datasets with certain characteristics.

  12. Exploring the Birth of Binary Stars

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    More than half of all stars are thought to be in binary or multiple star systems. But how do these systems form? The misaligned spins of some binary protostars might provide a clue.Two Formation ModelsIts hard to tell how multiple-star systems form, since these systems are difficult to observe in their early stages. But based on numerical simulations, there are two proposed models for the formation of stellar binaries:Turbulent fragmentationTurbulence within a single core leads to multiple dense clumps. These clumps independently collapse to form stars that orbit each other.Disk fragmentationGravitational instabilities in a massive accretion disk cause the formation of a smaller, secondary disk within the first, resulting in two stars that orbit each other.Log column density for one of the authors simulated binary systems, just after the formation of two protostars. Diamonds indicate the protostar positions. [Adapted from Offner et al. 2016]Outflows as CluesHow can we differentiate between these formation mechanisms? Led by Stella Offner (University of Massachusetts), a team of scientists has suggested that the key isto examine the alignment of the stars protostellar outflows jets that are often emitted from the poles of young, newly forming stars.Naively, wed expect that disk fragmentation would produce binary stars with common angular momentum. As the stars spins would be aligned, they would therefore also launch protostellar jets that were aligned with each other. Turbulent fragmentation, on the other hand, would cause the stars to have independent angular momentum. This would lead to randomly oriented spins, so the protostellar jets would be misaligned.Snapshots from the authors simulations. Left panel of each pair: column density; green arrows giveprotostellar spin directions. Right panel: synthetic observations produced from the simulations; cyan arrows giveprotostellar outflow directions. [Offner et al. 2016]Simulations of FragmentationIn order to better

  13. New spectroscopic binary companions of giant stars and updated metallicity distribution for binary systems

    CERN Document Server

    Bluhm, P; Vanzi, L; Soto, M G; Vos, J; Wittenmyer, R A; Olivares, F; Drass, H; Mennickent, R E; Vuckovic, M; Rojo, P; Melo, C H F

    2016-01-01

    We report the discovery of 24 spectroscopic binary companions to giant stars. We fully constrain the orbital solution for 6 of these systems. We cannot unambiguously derive the orbital elements for the remaining stars because the phase coverage is incomplete. Of these stars, 6 present radial velocity trends that are compatible with long-period brown dwarf companions.The orbital solutions of the 24 binary systems indicate that these giant binary systems have a wide range in orbital periods, eccentricities, and companion masses. For the binaries with restricted orbital solutions, we find a range of orbital periods of between $\\sim$ 97-1600 days and eccentricities of between $\\sim$ 0.1-0.4. In addition, we studied the metallicity distribution of single and binary giant stars. We computed the metallicity of a total of 395 evolved stars, 59 of wich are in binary systems. We find a flat distribution for these binary stars and therefore conclude that stellar binary systems, and potentially brown dwarfs, have a diffe...

  14. Towards the field binary population: Influence of orbital decay on close binaries

    CERN Document Server

    Korntreff, Christina; Pfalzner, Susanne

    2012-01-01

    Surveys of the binary populations in the solar neighbourhood have shown that the periods of G- and M-type stars are log-normally distributed. However, observations of young binary populations suggest a log-uniform distribution. Clearly some process(es) change the period distribution over time. Most stars form in star clusters, in which two important dynamical processes occur: i) gas-induced orbital decay of embedded binary systems and ii) destruction of soft binaries in three-body interactions. The emphasis here is on orbital decay which has been largely neglected so far. Using a combination of Monte-Carlo and dynamical nbody modelling it is demonstrated here that the cluster dynamics destroys the number of wide binaries, but leaves short-period binaries basically undisturbed even for a initially log-uniform distribution. By contrast orbital decay significantly reduces the number and changes the properties of short-period binaries, but leaves wide binaries largely uneffected. Until now it was unclear whether ...

  15. Effects of lubricants on binary direct compression mixtures.

    Science.gov (United States)

    Uğurlu, T; Halaçoğlu, M D; Türkoğlu, M

    2010-04-01

    The objective of this study was to investigate the effects of conventional lubricants including a new candidate lubricant on binary direct compression mixtures. Magnesium stearate (MGST), stearic acid (STAC), glyceryl behenate (COMP) and hexagonal boron nitride (HBN) were tested. The binary mixtures were 1:1 combinations of spray dried lactose (FlowLac 100), dicalcium phosphate dihydrate (Emcompress), and modified starch (Starch 1500) with microcrystalline cellulose (Avicel PH 102). Tablets were manufactured on a single-station instrumented tablet press with and without lubricants. In the case of unlubricated granules, the modified starch-microcrystalline cellulose mixture provided the highest percent compressibility value at 8.25%, spray dried lactose-microcrystalline cellulose mixture was 7.33%, and the dialcium phosphate dihydrate-microcrystalline cellulose mixture was 5.79%. Their corresponding tablet crushing strength values were: 104 N, 117 N, and 61 N, respectively. The lubricant concentrations studied were 0.5, 1, 2, and 4%. Effects of lubricant type and lubricant concentration on crushing strength were analyzed using a factorial ANOVA model. It was found that the Avicel PH 102-Starch 1500 mixture showed the highest lubricant sensitivity (110 N vs. 9 N), the least affected formulation was FlowLac-Avicel PH 102 mixture (118 N vs. 62 N). The crushing strength vs. concentration curve for MGST showed a typical biphasic profile, a fast drop up to 1% and a slower decline between 1 and 4%. The STAC, COMP, and HBN for all formulations showed a shallow linear decline of tablet crushing strength with increasing lubricant concentration. The HBN was as effective as MGST as a lubricant, and did not show a significant negative effect on the crushing strength of the tablets. The COMP and STAC also did not interfere with the crushing strength, however, they were not as effective lubricants as MGST or HBN. PMID:22491169

  16. Gravitational wave background from binary systems

    International Nuclear Information System (INIS)

    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter Ω(f), commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, Ω(f) is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the frequencies of all existing and planned detectors. A semi-analytical formula for Ω(f) is derived in the case of stellar binaries (containing white dwarfs, neutron stars or stellar-mass black holes). Besides a realistic expectation of the level of background, upper and lower limits are given, to account for the uncertainties in some astrophysical parameters such as binary coalescence rates. One interesting result concerns all current and planned ground-based detectors (including the Einstein Telescope). In their frequency range, the background of binaries is resolvable and only sporadically present. In other words, there is no stochastic background of binaries for ground-based detectors.

  17. Birth of Massive Black Hole Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Colpi, M.; /Milan Bicocca U.; Dotti, M.; /Insubria U., Como; Mayer, L.; /Zurich, ETH; Kazantzidis, S.; /KIPAC, Menlo Park

    2007-11-19

    If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.

  18. Poetry in Motion: Asteroseismology of Delta Scuti Stars in Binaries using Kepler Data

    CERN Document Server

    Liakos, Alexios

    2016-01-01

    The results of our six year systematic observational survey on candidate eclipsing binaries with a delta Sct component are briefly presented. A new catalogue for this kind of systems as well as the properties of their delta Sct members are also presented. The comparison between the components-pulsators and the single delta Sct stars shows that both the evolution and the pulsating properties differ significantly. Finally, we introduce the new era of studying stellar pulsations using high accuracy data from Kepler mission and emphasizing the great opportunities that are now opened for a deep knowledge of the properties of stellar pulsations.

  19. NGC300 X-1 and IC10 X-1: a new breed of black hole binary?

    OpenAIRE

    Barnard, R.; Clark, J. S.; Kolb, U. C.

    2008-01-01

    Context. IC 10 X-1 has recently been confirmed as a black hole (BH) + Wolf-Rayet (WR) X-ray binary, and NGC 300 X-1 is thought to be. The only other known BH+WR candidate is Cygnus X-3. IC 10 X-1 and NGC 300 X-1 have similar X-ray properties, with 0.3-10 keV luminosities ~1038 erg s-1, and their X-ray lightcurves exhibit orbital periods ~30 h. Aims. We investigate similarities between IC 10 X-1 and NGC 300 X-1, as well as differences between these systems and the known Galactic BH bina...

  20. Constraints on binary neutron star merger product from short GRB observations

    OpenAIRE

    Gao, He; Zhang, Bing; Lü, Hou-Jun

    2015-01-01

    Binary neutron star mergers are strong gravitational wave (GW) sources and the leading candidates to interpret short duration gamma-ray bursts (SGRBs). Under the assumptions that SGRBs are produced by double neutron star mergers and that the X-ray plateau followed by a steep decay as observed in SGRB X-ray light curves marks the collapse of a supra-massive neutron star to a black hole (BH), we use the statistical observational properties of {\\em Swift} SGRBs and the mass distribution of Galac...

  1. Evaluating historical candidate genes for schizophrenia.

    Science.gov (United States)

    Farrell, M S; Werge, T; Sklar, P; Owen, M J; Ophoff, R A; O'Donovan, M C; Corvin, A; Cichon, S; Sullivan, P F

    2015-05-01

    Prior to the genome-wide association era, candidate gene studies were a major approach in schizophrenia genetics. In this invited review, we consider the current status of 25 historical candidate genes for schizophrenia (for example, COMT, DISC1, DTNBP1 and NRG1). The initial study for 24 of these genes explicitly evaluated common variant hypotheses about schizophrenia. Our evaluation included a meta-analysis of the candidate gene literature, incorporation of the results of the largest genomic study yet published for schizophrenia, ratings from informed researchers who have published on these genes, and ratings from 24 schizophrenia geneticists. On the basis of current empirical evidence and mostly consensual assessments of informed opinion, it appears that the historical candidate gene literature did not yield clear insights into the genetic basis of schizophrenia. A likely reason why historical candidate gene studies did not achieve their primary aims is inadequate statistical power. However, the considerable efforts embodied in these early studies unquestionably set the stage for current successes in genomic approaches to schizophrenia. PMID:25754081

  2. Massive gaseous discs around SMBH binaries: Binary decay and tidal disruptions

    Directory of Open Access Journals (Sweden)

    Brem P.

    2012-12-01

    Full Text Available We investigate the evolution of black hole binaries embedded within geometrically thin gas discs. Our results imply that such discs can produce black hole mergers for relatively low-mass binaries, and that a significant population of eccentric binaries might exist at separations of a few 0.01 pc. These binaries may be detectable due to the time-variable accretion on to the black holes. If the disc fragments, then the newly-born stars will continue driving the binary to its coalescence, although at a slower rate. Interestingly, our preliminary analysis shows that these stars will be disrupted at a rate of ∼10−4–2 · 10−5 events per year per system.

  3. A SEARCH FOR BINARY ACTIVE GALACTIC NUCLEI: DOUBLE-PEAKED [O III] AGNs IN THE SLOAN DIGITAL SKY SURVEY

    International Nuclear Information System (INIS)

    We present active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS) having double-peaked profiles of [O III]λλ5007, 4959 and other narrow emission lines, motivated by the prospect of finding candidate binary AGNs. These objects were identified by means of a visual examination of 21,592 quasars at z < 0.7 in SDSS Data Release 7 (DR7). Of the spectra with adequate signal-to-noise, 148 spectra exhibit a double-peaked [O III] profile. Of these, 86 are Type 1 AGNs and 62 are Type 2 AGNs. Only two give the appearance of possibly being optically resolved double AGNs in the SDSS images, but many show close companions or signs of recent interaction. Radio-detected quasars are three times more likely to exhibit a double-peaked [O III] profile than quasars with no detected radio flux, suggesting a role for jet interactions in producing the double-peaked profiles. Of the 66 broad-line (Type 1) AGNs that are undetected in the FIRST survey, 0.9% show double-peaked [O III] profiles. We discuss statistical tests of the nature of the double-peaked objects. Further study is needed to determine which of them are binary AGNs rather than disturbed narrow line regions, and how many additional binaries may remain undetected because of insufficient line-of-sight velocity splitting. Previous studies indicate that 0.1% of SDSS quasars are spatially resolved binaries, with typical spacings of ∼10-100 kpc. If a substantial fraction of the double-peaked objects are indeed binaries, then our results imply that binaries occur more frequently at smaller separations (<10 kpc). This suggests that simultaneous fueling of both black holes is more common as the binary orbit decays through these spacings.

  4. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    XiangWu

    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.

  5. Closing the door on dark matter candidates

    International Nuclear Information System (INIS)

    Cold dark matter candidates - if they exist - will be present in, and perhaps dominate the mass density of, the halo of our Galaxy. As they pass the vicinity of the Sun, such halo particles will be focussed gravitationally, pass through the Sun and - occasionally - be captured and accumulate in the solar core. When the density in the core of the Sun of dark matter candidates has increased sufficiently, they will annihilate and among the annihilation products will be energetic (≥ GeV) ''ordinary'' neutrinos (νe, νμ, ντ) which are detectable in deep underground experiments. The event rates in such detectors from the capture and annihilation of various dark matter candidates (Dirac and Majorana neutrinos, Sneutrinos and Photinos) are presented and it is shown how comparison with data may lead to constraints on (or, the exclusion of) the masses of these particles. 6 refs

  6. Urey Prize Lecture: Binary Minor Planets

    Science.gov (United States)

    Margot, J. L.

    2004-11-01

    The discovery of binary systems in the near-Earth, main belt, and Kuiper belt populations provides an abundance of new data that expand our knowledge of the physics and chemistry of the solar system. Binary minor planets form as a result of collisional, tidal, and capture processes that are important to study as they play major roles in the formation and evolution of planetary systems. The frequency of occurrence of such processes directly reflects the dynamical environment in the various populations. Observations of binaries provide a powerful way to measure the bulk properties of small bodies, which in turn lead to inferences about their composition and internal structure. These data may offer a rare glimpse of what physical and chemical conditions prevailed when protoplanets formed, and what subsequent evolution took place. In the case of the Kuiper Belt, the study of a handful of binaries forces us to rethink how dense and how bright these bodies are, and to significantly revise our current mass estimates for the entire population. The number of known binary minor planets has increased dramatically over the past few years, with roughly ten new discoveries each year. I will attempt to summarize recent developments, with examples drawn from my observations with the Hubble, Palomar, Keck, Arecibo and Goldstone telescopes.

  7. Orbital eccentricities in primordial black holes binaries

    CERN Document Server

    Cholis, Ilias; Ali-Haïmoud, Yacine; Bird, Simeon; Kamionkowski, Marc; Muñoz, Julian B; Raccanelli, Alvise

    2016-01-01

    It was recently suggested that the merger of $\\sim30\\,M_\\odot$ primordial black holes (PBHs) may provide a significant number of events in gravitational-wave observatories over the next decade, if they make up an appreciable fraction of the dark matter. Here we show that measurement of the eccentricities of the inspiralling binary black holes can be used to distinguish these binaries from those produced by more traditional astrophysical mechanisms. These PBH binaries are formed on highly eccentric orbits and can then merge on timescales that in some cases are years or less, retaining some eccentricity in the last seconds before the merger. This is to be contrasted with massive-stellar-binary, globular-cluster, or other astrophysical origins for binary black holes (BBHs) in which the orbits have very effectively circularized by the time the BBH enters the observable LIGO window. Here we discuss the features of the gravitational-wave signals that indicate this eccentricity and forecast the sensitivity of LIGO a...

  8. Spherical hashing: binary code embedding with hyperspheres.

    Science.gov (United States)

    Heo, Jae-Pil; Lee, Youngwoon; He, Junfeng; Chang, Shih-Fu; Yoon, Sung-Eui

    2015-11-01

    Many binary code embedding schemes have been actively studied recently, since they can provide efficient similarity search, and compact data representations suitable for handling large scale image databases. Existing binary code embedding techniques encode high-dimensional data by using hyperplane-based hashing functions. In this paper we propose a novel hypersphere-based hashing function, spherical hashing, to map more spatially coherent data points into a binary code compared to hyperplane-based hashing functions. We also propose a new binary code distance function, spherical Hamming distance, tailored for our hypersphere-based binary coding scheme, and design an efficient iterative optimization process to achieve both balanced partitioning for each hash function and independence between hashing functions. Furthermore, we generalize spherical hashing to support various similarity measures defined by kernel functions. Our extensive experiments show that our spherical hashing technique significantly outperforms state-of-the-art techniques based on hyperplanes across various benchmarks with sizes ranging from one to 75 million of GIST, BoW and VLAD descriptors. The performance gains are consistent and large, up to 100 percent improvements over the second best method among tested methods. These results confirm the unique merits of using hyperspheres to encode proximity regions in high-dimensional spaces. Finally, our method is intuitive and easy to implement. PMID:26440269

  9. An interferometric view of binary stars

    CERN Document Server

    Boffin, Henri M J

    2016-01-01

    The study of binary stars is critical to apprehend many of the most interesting classes of stars. Moreover, quite often, the study of stars in binary systems is our only mean to constrain stellar properties, such as masses and radii. Unfortunately, a great fraction of the most interesting binaries are so compact that they can only be apprehended by high-resolution techniques, mostly by interferometry. I present some results highlighting the use of interferometry in the study of binary stars, from finding companions and deriving orbits, determining the mass and radius of stars, to studying mass transfer in symbiotic stars, and tackling luminous blue variables. In particular, I show how interferometric studies using the PIONIER instrument have allowed us to confirm a dichotomy within symbiotic stars, obtain masses of stars with a precision better than 1%, and help us find a new Eta Carinae-like system. I will also illustrate the benefits for the study of binary stars one would get from upgrading the VLT Interfe...

  10. Planet Scattering Around Binaries: Ejections, Not Collisions

    Science.gov (United States)

    Smullen, Rachel A.; Kratter, Kaitlin M.; Shannon, Andrew

    2016-06-01

    Transiting circumbinary planets discovered by Kepler provide unique insight into binary star and planet formation. Several features of this new found population, for example the apparent pile-up of planets near the innermost stable orbit, may distinguish between formation theories. In this work, we determine how planet-planet scattering shapes planetary systems around binaries as compared to single stars. In particular, we look for signatures that arise due to differences in dynamical evolution in binary systems. We carry out a parameter study of N-body scattering simulations for four distinct planet populations around both binary and single stars. While binarity has little influence on the final system multiplicity or orbital distribution, the presence of a binary dramatically effects the means by which planets are lost from the system. Most circumbinary planets are lost due to ejections rather than planet-planet or planet-star collisions. The most massive planet in the system tends to control the evolution. Systems similar to the only observed multi-planet circumbinary system, Kepler-47, can arise from much more tightly packed, unstable systems. Only extreme initial conditions introduce differences in the final planet populations. Thus, we suggest that any intrinsic differences in the populations are imprinted by formation.

  11. Investigating Dark Energy with Black Hole Binaries

    International Nuclear Information System (INIS)

    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.

  12. Potential Optical Counterparts to High Mass X-Ray and γ-Ray Binaries

    Science.gov (United States)

    Mitchell, Carl; McSwain, M. V.

    2011-01-01

    We seek to identify optical counterparts to several previously discovered high mass X-ray binaries and γ-ray sources from the Liu et al. and Fermi first year catalogues. Observations were taken with the CTIO 0.9-meter telescope, operated by the SMARTS Consortium. Photometric data were taken in the Strömgren b and y filters, as well as a narrow-band Hα filter. We present color-color diagrams of y-Hα vs. b-y for each field, and candidates for optical counterparts were selected based on their excesses of Hα emission. We also present spectral energy distributions for select candidates. This work is supported by the NSF REU site grant PHY-0849416, NASA DPR No. NNX09AT67G, and Lehigh University. We also thank the SMARTS Consortium, Rachael Roettenbacher, Tina Aragona, and Amber Marsh.

  13. Compact symmetric objects and supermassive binary black holes in the VLBA Imaging and Polarimetry Survey

    Science.gov (United States)

    Tremblay, S. E.; Taylor, G. B.; Ortiz, A. A.; Tremblay, C. D.; Helmboldt, J. F.; Romani, R. W.

    2016-06-01

    We present multifrequency Very Long Baseline Array (VLBA) follow-up observations of VLBA Imaging and Polarimetry Survey sources identified as likely compact symmetric objects (CSOs) or supermassive binary black holes (SBBHs). We also present new spectroscopic redshifts for 11 sources observed with the Hobby-Eberly Telescope. While no new SBBHs can be confirmed from these observations, we have identified 24 CSOs in the sample, 15 of which are newly designated, and refuted 52 candidates leaving 33 unconfirmed candidates. This is the first large uniform sample of CSOs which can be used to elicit some of the general properties of these sources, including morphological evolution and environmental interaction. We have detected polarized emission from two of these CSOs the properties of which are consistent with active galactic nuclei unification schemes.

  14. Compact Symmetric Objects and Supermassive Binary Black Holes in the VLBA Imaging and Polarimetry Survey

    CERN Document Server

    Tremblay, S E; Ortiz, A A; Tremblay, C D; Helmboldt, J F; Romani, R W

    2016-01-01

    We present multi-frequency Very Long Baseline Array (VLBA) follow-up observations of VLBA Imaging and Polarimetry Survey sources identified as likely compact symmetric objects (CSOs) or super-massive binary black holes (SBBHs). We also present new spectroscopic redshifts for 11 sources observed with the Hobby-Eberly Telescope. While no new SBBHs can be confirmed from these observations, we have identified 24 CSOs in the sample, 15 of which are newly designated, and refuted 52 candidates leaving 33 unconfirmed candidates. This is the first large uniform sample of CSOs which can be used to elicit some of the general properties of these sources, including morphological evolution and environmental interaction. We have detected polarised emission from two of these CSOs the properties of which are consistent with Active Galactic Nuclei unification schemes.

  15. Cattle Candidate Genes for Meat Production Traits

    OpenAIRE

    Bláhová, Alice

    2013-01-01

    The objective of this study was to compile a summary of the most important candidate genes for meat production. The studied genes were: GH, GHR, MSTN, MyoD family, leptin, IGF, TG5, SCD, DGAT and STAT5A. Growth hormone (GH) is involved in physiological processes of growth and metabolism. Growth hormone receptor (GHR) has been proposed as a candidate gene for meat production in cattle. Myostatin is a significant marker. It affects the amount of muscle, reduces marbling and elevate meat tendern...

  16. INTEGRAL & RXTE View of Gamma-ray Binaries

    OpenAIRE

    Jian LI; Torres, Diego F.; Zhang, Shu; WANG, JIANMIN

    2013-01-01

    Gamma-ray binaries are X-ray binaries with gamma-ray emissions. Their multi-wavelength emissions range from radio, optical, X-ray and to very high energy (TeV). X-ray emissions are crucial to understand the nature of gamma-ray binaries. INTEGRAL and RXTE have covered and monitored most of the gamma-ray binaries in hard and soft X-rays. Here we report the results of several gamma-ray binaries and possible gamma-ray binaries from INTEGRAL and RXTE.

  17. The Circulation Pattern in Simulated Contact Binaries

    Science.gov (United States)

    Motl, Patrick M.; Frank, J.; Tohline, J. E.

    2006-06-01

    We present a three-dimensional hydrodynamical simulation of an initially symmetric (equal mass) binary where both components are marginally in contact. The simulation evolves the binary through approximately 150 orbital periods and within the first 20 orbits, a global velocity field is established that carries material between both components. In the equatorial plane, the flow is along a figure eight pattern with streams of material sliding past one another in the neighborhood of the inner Lagrange point. For our chosen equation of state, mass transfer is ultimately unstable in this binary though the growth time is long compared to the orbital period. We are therefore able to observe that the circulation pattern, once established, is quite close to steady state. We explore the role that similar steady state flows may play in real contact systems.

  18. TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

    International Nuclear Information System (INIS)

    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 105-106 years.

  19. Gravitational waves from spinning eccentric binaries

    CERN Document Server

    Csizmadia, Péter; Rácz, István; Vasúth, Mátyás

    2012-01-01

    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. In addition, by investigating the validity of the energy balance relat...

  20. Binary Particle Model of Weak Interactions

    CERN Document Server

    Ndili, F N

    2011-01-01

    We introduce the new concept of binary particle as the basic matter unit that participates in weak interactions and not any one fermion singly. We state the quantum numbers of this binary particle, and show the concept leads us to a natural explanation of the standard model puzzle of the origin of flavor mixing and the CKM matrix. Certain other puzzles of the standard model such as the absence of flavor changing neutral currents (FCNC), are also explained naturally by the binary particle model. These puzzles are currently thought to be esoteric properties of electro weak interactions that have origins in physics beyond the standard model at some ultra high energy scales. We show that this is not necessarily the case.

  1. A binary spelling interface with random errors.

    Science.gov (United States)

    Perelmouter, J; Birbaumer, N

    2000-06-01

    An algorithm for design of a spelling interface based on a modified Huffman's algorithm is presented. This algorithm builds a full binary tree that allows to maximize an average probability to reach a leaf where a required character is located when a choice at each node is made with possible errors. A means to correct errors (a delete-function) and an optimization method to build this delete-function into the binary tree are also discussed. Such a spelling interface could be successfully applied to any menu-orientated alternative communication system when a user (typically, a patient with devastating neuromuscular handicap) is not able to express an intended single binary response, either through motor responses or by using of brain-computer interfaces, with an absolute reliability. PMID:10896195

  2. 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."

  3. Modeling Flows Around Merging Black Hole Binaries

    CERN Document Server

    van Meter, James R; Miller, M Coleman; Reynolds, Christopher S; Centrella, Joan M; Baker, John G; Boggs, William D; Kelly, Bernard J; McWilliams, Sean T

    2009-01-01

    Coalescing massive black hole binaries are produced by the mergers of galaxies. The final stages of the black hole coalescence produce strong gravitational radiation that can be detected by the space-borne LISA. In cases where the black hole merger takes place in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Modeling such electromagnetic counterparts of the final merger requires evolving the behavior of both gas and fields in the strong-field regions around the black holes. We have taken a step towards solving this problem by mapping the flow of pressureless matter in the dynamic, 3-D general relativistic spacetime around the merging black holes. We find qualitative differences in collision and outflow speeds, including a signature of the merger when the net angular momentum of the matter is low, between the results from single and binary black holes, and between nonrotating and rotating holes in binaries. If future magnetohydrodynamic results confirm ...

  4. Nonlinear Tides in Close Binary Systems

    CERN Document Server

    Weinberg, Nevin N; Quataert, Eliot; Burkart, Josh

    2011-01-01

    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 effects: three-mode nonlinear interactions and nonlinear excitation of modes by the time-varying gravitational potential of the companion. This paper presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism is applicable to binaries containing stars, planets, or compact objects, we focus on solar type stars with stellar or planetary companions. Our primary results include: (1) The linear tidal solution often used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited gravity waves are unstable to parametric resonance for companion masses M' > 10-100 M_Earth at orbital periods P = 1-10 days. The nearly static equilibrium tide is, however, parametrically s...

  5. Gravitational wave background from binary systems

    CERN Document Server

    Rosado, Pablo A

    2011-01-01

    Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter $\\Omega(f)$, commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, $\\Omega(f)$ is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the ...

  6. Binary Code Disassembly for Reverse Engineering

    Directory of Open Access Journals (Sweden)

    Marius Popa

    2013-01-01

    Full Text Available The disassembly of binary file is used to restore the software application code in a readable and understandable format for humans. Further, the assembly code file can be used in reverse engineering processes to establish the logical flows of the computer program or its vulnerabilities in real-world running environment. The paper highlights the features of the binary executable files under the x86 architecture and portable format, presents issues of disassembly process of a machine code file and intermediate code, disassembly algorithms which can be applied to a correct and complete reconstruction of the source file written in assembly language, and techniques and tools used in binary code disassembly.

  7. Supermassive Black Hole Binaries as Galactic Blenders

    CERN Document Server

    Kandrup, H E; Terzic, B; Bohn, C L; Kandrup, Henry E.; Sideris, Ioannis V.; Terzic, Balsa; Bohn, Courtlandt L.

    2003-01-01

    This paper focuses on the dynamical implications of close supermassive black hole binaries both as an example of resonant phase mixing and as a potential explanation of inversions and other anomalous features observed in the luminosity profiles of some elliptical galaxies. The presence of a binary comprised of black holes executing nearly periodic orbits leads to the possibility of a broad resonant coupling between the black holes and various stars in the galaxy. This can result in efficient chaotic phase mixing and, in many cases, systematic increases in the energies of stars and their consequent transport towards larger radii. Allowing for the presence of a supermassive black hole binary with plausible parameter values near the center of a spherical, or nearly spherical, galaxy characterised initially by a Nuker density profile enables one to reproduce in considerable detail the central surface brightness distributions of such galaxies as NGC 3706.

  8. Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Lumninous Infrared Galaxy Candidates

    Science.gov (United States)

    Griffith, Roger L.; Kirkpatrick, J. Davy; Eisenhardt, Peter R. M.; Gelino, Christopher R.; Cushing, Michael C.; Benford, Dominic; Blain, Andrew; Bridge, Carrie R.; Cohen, Martin; Cutri, Roc M.; Donoso, Emilio; Jarrett, Thomas H.; Lonsdale, Carol; Mace, Gregory; Mainzer, A.; Marsh, Ken; Padgett, Deborah; Petty, Sara; Ressler, Michael E.; Skrutskie, Michael F.; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

    2012-01-01

    We present Spitzer 3.6 and 4.5 micrometer photometry and positions for a sample of 1510 brown dwarf candidates identified by the Wide-field Infrared Survey Explorer (WISE) all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12). Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify seven fainter (4.5 m to approximately 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy candidates. For this control sample, we find another six brown dwarf candidates, suggesting that the seven companion candidates are not physically associated. In fact, only one of these seven Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this, there is no evidence for any widely separated (greater than 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of 7.33 x 10(exp 5) objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 m photometry, along with positionally matched B and R photometry from USNO-B; J, H, and Ks photometry from Two Micron All-Sky Survey; and W1, W2, W3, and W4 photometry from the WISE all-sky catalog.

  9. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. I. S-TYPE BINARIES

    International Nuclear Information System (INIS)

    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

  10. 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.

  11. Binary black holes' effects on electromagnetic fields.

    Science.gov (United States)

    Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David

    2009-08-21

    In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves. PMID:19792706

  12. Spin supplementary conditions for spinning compact binaries

    CERN Document Server

    Mikóczi, Balázs

    2016-01-01

    We consider the different spin supplementary conditions (SSC) for a spinning compact binary with the leading-order spin-orbit (SO) interaction. The Lagrangian of the binary system can be constructed but it is acceleration-dependent in two cases of SSC. We rewrite the generalized Hamiltonian formalism proposed by Ostrogradsky and compute the conservative quantities and the dissipative part of relative motion during the gravitational radiation of each SSCs. We give the orbital elements and observed quantities of the SO dynamics, for instance the energy and the orbital angular momentum losses and waveforms and discuss their SSC dependence.

  13. Quasi periodic oscillations in black hole binaries

    CERN Document Server

    Motta, S E

    2016-01-01

    Fast time variability is the most prominent characteristic of accreting systems and the presence of quasi periodic oscillations (QPOs) is a constant in all accreting systems, from cataclysmic variables to AGNs, passing through black hole and neutron star X-ray binaries and through the enigmatic ultra-luminous X-ray sources. In this paper I will briefly review the current knowledge of QPOs in black hole X-ray binaries, mainly focussing on their observed properties, but also mentioning the most important models that have been proposed to explain the origin of QPOs over the last decades.

  14. Photometric constraints on binary asteroid dynamics

    Science.gov (United States)

    Scheirich, Peter

    2015-08-01

    To date, about 50 binary NEAs, 20 Mars-crossing and 80 small MB asteroids are known. We observe also a population of about 200 unbound asteroid systems (asteroid pairs). I will review the photometric observational data we have for the best observed cases and compare them with theories of binary and paired asteroids evolution.The observed characteristics of asteroid systems suggest their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits of observed binary systems are non-random; the orbital poles concentrate near the obliquities of 0 and 180 degrees, i.e., near the YORP asymptotic states.Recently, a significant excess of retrograde satellite orbits was detected, which is not yet explained characteristic.An evolution of binary system depend heavily on the BYORP effect. If BYORP is contractive, the primary and secondary could end in a tidal-BYORP equilibrium. Observations of mutual events between binary components in at least four apparitions are needed for BYORP to be revealed by detecting a quadratic drift in mean anomaly of the satellite. I will show the observational evidence of single-synchronous binary asteroid with tidally locked satellite (175706 1996 FG3), i.e, with the quadratic drift equal to zero, and binary asteroid with contracting orbit (88710 2001 SL9), with positive value of the quadratic drift (the solution for the quadratic drift is ambiguous so far, with possible values of 5 and 8 deg/yr2).The spin configuration of the satellite play a crucial role in the evolution of the system under the influence of the BYORP effect. I will show that the rotational lightcurves of the satellites show that most of them have small libration amplitudes (up to 20 deg.), with a few interesting exceptions.Acknowledgements: This work has been supported by the Grant Agency of the Czech Republic, Grant P209

  15. 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.

  16. Inducing Risk Neutral Preferences with Binary Lotteries

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... 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...... toward risk neutrality. This striking result generalizes to the case in which subjects make several lottery choices and one is selected for payment....

  17. Toroidal Horizons in Binary Black Hole Mergers

    OpenAIRE

    Bohn, Andy; Kidder, Lawrence E.; Teukolsky, Saul A.

    2016-01-01

    We find the first binary black hole event horizon with a toroidal topology. It had been predicted that generically the event horizons of merging black holes should briefly have a toroidal topology, but such a phase has never been seen prior to this work. In all previous binary black hole simulations, in the coordinate slicing used to evolve the black holes, the topology of the event horizon transitions directly from two spheres during the inspiral to a single sphere as the black holes merge. ...

  18. Binaries in the Hipparcos data: Keep digging

    OpenAIRE

    Pourbaix, D.; Jancart, S.; Jorissen, A.

    2004-01-01

    Among the 120 000 objects in the Hipparcos catalogue, only 235 were fitted with an orbital model. Besides these 235 original astrometric binaries, most Hipparcos entries with a known spectroscopic orbit (extrasolar planet or stellar companion) have now been re-processed, as part of the on-going construction of the 9th Catalogue of Spectroscopic Binary Orbits (SB9, available at http://sb9.astro.ulb.ac.be). The pitfalls and successes of this re-processing are discussed in various contexts, like...

  19. Apsidal motion in eclipsing binary GG Orionis

    Science.gov (United States)

    Yilan, E.; Bulut, I.

    2016-03-01

    The study of apsidal motion in binary stars with eccentric orbit is well known as an important source of information for the stellar internal structure as well as the possibility of verification of general relativity. In this study, the apsidal motion of the eccentric eclipsing binary GG Ori (P = 6.631 days, e = 0.22) has been analyzed using the times of minimum light taken from the literature and databases and the elements of apsidal motion have been computed. The method described by Giménez and García-Pelayo (1983) has been used for the apsidal motion analysis.

  20. Decomposition of Binary Signed-Graphic Matroids

    CERN Document Server

    Pitsoulis, Leonidas

    2010-01-01

    In this paper we employ Tutte's theory of bridges to derive a decomposition theorem for binary matroids arising from signed graphs. The proposed decomposition differs from previous decomposition results on matroids that have appeared in the literature in the sense that it is not based on $k$-sums, but rather on the operation of deletion of a cocircuit. Specifically, it is shown that certain minors resulting from the deletion of a cocircuit of a binary matroid will be graphic matroids apart from exactly one that will be signed-graphic, if and only if the matroid is signed-graphic.

  1. Quantitative spectroscopy of close binary stars

    CERN Document Server

    Pavlovski, K

    2011-01-01

    The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution, a vital aspect in understanding the evolution of stellar systems. We review different ways to reconstruct individual spectra from eclipsing and non-eclipsing systems, and then concentrate on some recent applications to detached binaries with high-mass and intermediate-mass stars, and Algol-type mass-transfer systems.

  2. Promoting Team Leadership Skills in Doctoral Candidates

    Science.gov (United States)

    Suleiman, Mahmoud; Whetton, Danny

    2014-01-01

    Doctoral programs can serve as an optimal opportunity for candidates to engage in tasks and activities to transform them and their schools. The paradigm shifts in such preparation involve moving from sitting and getting to making and taking. Most importantly, it requires building leadership skills and styles necessary to bring about desired change…

  3. Secondary Teacher Candidates' Lesson Planning Learning

    Science.gov (United States)

    Santoyo, Christina; Zhang, Shaoan

    2016-01-01

    Teacher candidates (TCs) use clinical experiences to enact concepts taught in their university courses; therefore field experiences may be the most important component of teacher preparation (Hammerness et al., 2005). TCs require support and guidance as they learn to adapt curriculum materials for effective use in the classroom (Davis, 2006). They…

  4. The Responsibility Education of Teacher Candidates

    Science.gov (United States)

    Toremen, Fatih

    2011-01-01

    In this study, it was aimed to take the views and suggestions of academicians working at the faculty of education on what can be done about teacher candidates' responsibility education. This study was designed on the basis of qualitative research approach and purposive sampling method was used. Data were collected by unstructured interview method…

  5. FAME's Search for Extrasolar Planet Candidates

    Science.gov (United States)

    Johnston, K.

    FAME is a five year survey mission to observe the positions, proper motions, and parallaxes of 40,000,000 stars down to 15th magnitude with accuracies of 50 microarcseconds at 9th magnitude. In addition to producing an astrometric and photometric catalog unparalleled for its accuracy and size, the survey will provide significant astrophysics results and search for extrasolar planet candidates.

  6. Query by image example: The CANDID approach

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, P.M.; Cannon, M. [Los Alamos National Lab., NM (United States). Computer Research and Applications Group; Hush, D.R. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering

    1995-02-01

    CANDID (Comparison Algorithm for Navigating Digital Image Databases) was developed to enable content-based retrieval of digital imagery from large databases using a query-by-example methodology. A user provides an example image to the system, and images in the database that are similar to that example are retrieved. The development of CANDID was inspired by the N-gram approach to document fingerprinting, where a ``global signature`` is computed for every document in a database and these signatures are compared to one another to determine the similarity between any two documents. CANDID computes a global signature for every image in a database, where the signature is derived from various image features such as localized texture, shape, or color information. A distance between probability density functions of feature vectors is then used to compare signatures. In this paper, the authors present CANDID and highlight two results from their current research: subtracting a ``background`` signature from every signature in a database in an attempt to improve system performance when using inner-product similarity measures, and visualizing the contribution of individual pixels in the matching process. These ideas are applicable to any histogram-based comparison technique.

  7. Candidal Leukoplakia on Patient with Removable Denture

    Directory of Open Access Journals (Sweden)

    Shiril Paskalis

    2013-07-01

    Full Text Available Candida infection is a common problem in patients using removable dentures, with the most frequent type is denture stomatitis. But other type of candidal infection could also happen in these patients, such as candidal leukoplakia. We reported a 61 years old female patient who complained a painful lesion under her lower removable denture. Oral examination revealed white plaque that could not be rubbed over an ulcer on the lingual part of alveolar processes under the lower removable denture plate, and also an erythematous area on palatum durum above the upper full denture. The patient was suspected to have candidal leukoplakia on the lingual part of the mandible and denture stomatitis on the palate area. The treatment consisted of nystatin oral suspension, chlorhexidine solution, multivitamins, along with denture replacement and oral health education. The entire lesion resolved within 2 months therapy. Candidal infection treatment on denture patient needs not only medication or denture replacement, but also patient compliance to achieve maximal result.

  8. Social Justice Perceptions of Teacher Candidates

    Science.gov (United States)

    Turhan, Muhammed

    2010-01-01

    This study aims to determine the social justice perceptions of teacher candidates being trained in an education faculty. For this purpose, national and international literature was reviewed by the researcher and a 32-item questionnaire was developed and implemented on 237 senior year education faculty students. Data from the questionnaires were…

  9. Gallium-67 imaging in candidal esophagitis

    Energy Technology Data Exchange (ETDEWEB)

    Rundback, J.H.; Goldfarb, C.R.; Ongseng, F. (Beth Israel Medical Center, New York, NY (USA))

    1990-01-01

    Ga-67 scanning has been used to evaluate esophageal carcinoma. It has demonstrated candidal infection in other body sites and, in one previous case, in the esophagus. The authors present a case of diffuse esophageal uptake of Ga-67 in esophageal candidiasis.

  10. Gallium-67 imaging in candidal esophagitis

    International Nuclear Information System (INIS)

    Ga-67 scanning has been used to evaluate esophageal carcinoma. It has demonstrated candidal infection in other body sites and, in one previous case, in the esophagus. The authors present a case of diffuse esophageal uptake of Ga-67 in esophageal candidiasis

  11. Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae.

    Science.gov (United States)

    Fryer, Chris L; Oliveira, F G; Rueda, J A; Ruffini, R

    2015-12-01

    Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E_{iso}≳10^{52}  erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs. PMID:26684106

  12. Retrograde binaries of massive black holes in circum-binary accretion discs

    OpenAIRE

    Amaro-Seoane, Pau; Maureira-Fredes, Cristián; Dotti, Massimo; Colpi, Monica

    2016-01-01

    We explore the hardening of a massive black hole binary embedded in a circum-binary gas disc when the binary and the gas are coplanar and the gas is counter-rotating. The secondary black hole, revolving in the direction opposite to the gas, experiences a drag from gas-dynamical friction and from direct accretion of part of it. Using two-dimensional (2D) hydrodynamical grid simulations we investigate the effect of changing the accretion prescriptions on the dynamics of the secondary black hole...

  13. A Survey Design for a Sensitive Binary Variable Correlated with Another Nonsensitive Binary Variable

    OpenAIRE

    Jun-Wu Yu; Guo-Liang Tian; Yang Lu

    2013-01-01

    Tian et al. (2007) introduced a so-called hidden sensitivity model for evaluating the association of two sensitive questions with binary outcomes. However, in practice, we sometimes need to assess the association between one sensitive binary variable (e.g., whether or not a drug user, the number of sex partner being ⩽1 or >1, and so on) and one nonsensitive binary variable (e.g., good or poor health status, with or without cervical cancer, and so on). To address this issue, by sufficiently ut...

  14. Adiabatic Mass Loss Model in Binary Stars

    Science.gov (United States)

    Ge, H. W.

    2012-07-01

    Rapid mass transfer process in the interacting binary systems is very complicated. It relates to two basic problems in the binary star evolution, i.e., the dynamically unstable Roche-lobe overflow and the common envelope evolution. Both of the problems are very important and difficult to be modeled. In this PhD thesis, we focus on the rapid mass loss process of the donor in interacting binary systems. The application to the criterion of dynamically unstable mass transfer and the common envelope evolution are also included. Our results based on the adiabatic mass loss model could be used to improve the binary evolution theory, the binary population synthetic method, and other related aspects. We build up the adiabatic mass loss model. In this model, two approximations are included. The first one is that the energy generation and heat flow through the stellar interior can be neglected, hence the restructuring is adiabatic. The second one is that he stellar interior remains in hydrostatic equilibrium. We model this response by constructing model sequences, beginning with a donor star filling its Roche lobe at an arbitrary point in its evolution, holding its specific entropy and composition profiles fixed. These approximations are validated by the comparison with the time-dependent binary mass transfer calculations and the polytropic model for low mass zero-age main-sequence stars. In the dynamical time scale mass transfer, the adiabatic response of the donor star drives it to expand beyond its Roche lobe, leading to runaway mass transfer and the formation of a common envelope with its companion star. For donor stars with surface convection zones of any significant depth, this runaway condition is encountered early in mass transfer, if at all; but for main sequence stars with radiative envelopes, it may be encountered after a prolonged phase of thermal time scale mass transfer, so-called delayed dynamical instability. We identify the critical binary mass ratio for the

  15. Eclipsing binaries and fast rotators in the Kepler sample. Characterization via radial velocity analysis from Calar Alto

    CERN Document Server

    Lillo-Box, J; Mancini, L; Henning, Th; Figueira, P; Ciceri, S; Santos, N

    2015-01-01

    The Kepler mission has provided high-accurate photometric data in a long time span for more than two hundred thousands stars, looking for planetary transits. Among the detected candidates, the planetary nature of around 15% has been established or validated by different techniques. But additional data is needed to characterize the rest of the candidates and reject other possible configurations. We started a follow-up program to validate, confirm, and characterize some of the planet candidates. In this paper we present the radial velocity analysis (RV) of those presenting large variations, compatible with being eclipsing binaries. We also study those showing large rotational velocities, which prevents us from obtaining the necessary precision to detect planetary-like objects. We present new RV results for 13 Kepler objects of interest (KOIs) obtained with the CAFE spectrograph at the Calar Alto Observatory, and analyze their high-spatial resolution images and the Kepler light curves of some interesting cases. ...

  16. Evolution of Binary Stars in Multiple-Population Globular Clusters

    CERN Document Server

    Hong, Jongsuk; Sollima, Antonio; McMillan, Stephen L W; D'Antona, Franca; D'Ercole, Annibale

    2015-01-01

    The discovery of multiple stellar populations in globular clusters has implications for all the aspects of the study of these stellar systems. In this paper, by means of N-body simulations, we study the evolution of binary stars in multiple-population clusters and explore the implications of the initial differences in the spatial distribution of different stellar populations for the evolution and survival of their binary stars. Our simulations show that initial differences between the spatial distribution of first-generation (FG) and second-generation (SG) stars can leave a fingerprint in the current properties of the binary population. SG binaries are disrupted more efficiently than those of the FG population resulting in a global SG binary fraction smaller than that of the FG. As for surviving binaries, dynamical evolution produces a difference between the SG and the FG binary binding energy distribution with the SG population characterized by a larger fraction of high binding energy (more bound) binaries. ...

  17. Model-independent inference on compact-binary observations

    CERN Document Server

    Mandel, Ilya; Colonna, Andrea; Stevenson, Simon; Tiňo, Peter; Veitch, John

    2016-01-01

    The recent advanced LIGO detections of gravitational waves from merging binary black holes enhance the prospect of exploring binary evolution via gravitational-wave observations of a population of compact-object binaries. In the face of uncertainty about binary formation models, model-independent inference provides an appealing alternative to comparisons between observed and modelled populations. We describe a procedure for clustering in the multi-dimensional parameter space of observations that are subject to significant measurement errors. We apply this procedure to a mock data set of population-synthesis predictions for the masses of merging compact binaries convolved with realistic measurement uncertainties, and demonstrate that we can accurately distinguish subpopulations of binary neutron stars, binary black holes, and mixed black hole -- neutron star binaries.

  18. BINARY ASTEROID ENCOUNTERS WITH TERRESTRIAL PLANETS: TIMESCALES AND EFFECTS

    International Nuclear Information System (INIS)

    Many asteroids that make close encounters with terrestrial planets are in a binary configuration. Here, we calculate the relevant encounter timescales and investigate the effects of encounters on a binary's mutual orbit. We use a combination of analytical and numerical approaches with a wide range of initial conditions. Our test cases include generic binaries with close, moderate, and wide separations, as well as seven well-characterized near-Earth binaries. We find that close approaches (<10 Earth radii) occur for almost all binaries on 1-10 million year timescales. At such distances, our results suggest substantial modifications to a binary's semimajor axis, eccentricity, and inclination, which we quantify. Encounters within 30 Earth radii typically occur on sub-million year timescales and significantly affect the wider binaries. Important processes in the lives of near-Earth binaries, such as tidal and radiative evolution, can be altered or stopped by planetary encounters.

  19. 22 CFR 11.8 - Travel expenses of candidates.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Travel expenses of candidates. 11.8 Section 11... Travel expenses of candidates. The travel and other personal expenses of candidates incurred in... Department may issue round-trip invitational travel orders to bring candidates to Washington at...

  20. The Fermi LAT view of the colliding wind binaries

    CERN Document Server

    Pshirkov, Maxim S

    2015-01-01

    Colliding wind binaries (CWBs) have been considered as a possible high energy $\\gamma$-ray sources for some time, however no system other than $\\eta$ Car has been detected. In the paper a sample of seven CWBs (WR 11, WR 70, WR 137, WR 140, WR 146, WR 147) which were deemed most favourable candidates by a theoretic modelling was analyzed and almost 7 years of the Fermi-LAT data was used. WR 11 ($\\gamma^2$ Vel) was detected at 6.1$\\sigma$ significance level with a photon flux in 0.1-100 GeV range $(1.8\\pm0.6)\\times10^{-9}~\\mathrm{ph~cm^{-2}~s^{-1}}$, the energy flux $(2.7\\pm0.5)\\times10^{-12}~~\\mathrm{erg~cm^{-2}~s^{-1}}$. At the adopted distance $d=340$ pc that corresponds to luminosity $L=(3.7\\pm0.7)\\times10^{31}~\\mathrm{erg~s^{-1}}$. This luminosity amounts to $\\sim2\\times10^{-6}$ fraction of total wind kinetic power and $\\sim2\\times10^{-4}$ fraction of power injected into the wind-wind interaction region of this system. Upper limits were set on the high-energy flux from the WR 70 and WR 140 systems.

  1. Binary dynamics on star networks under external perturbations.

    Science.gov (United States)

    Moreira, Carolina A; Schneider, David M; de Aguiar, Marcus A M

    2015-10-01

    We study a binary dynamical process that is a representation of the voter model with two candidates and opinion makers. The voters are represented by nodes of a network of social contacts with internal states labeled 0 or 1 and nodes that are connected can influence each other. The network is also perturbed by opinion makers, a set of external nodes whose states are frozen in 0 or 1 and that can influence all nodes of the network. The quantity of interest is the probability of finding m nodes in state 1 at time t. Here we study this process on star networks, which are simple representations of hubs found in complex systems, and compare the results with those obtained for networks that are fully connected. In both cases a transition from disordered to ordered equilibrium states is observed as the number of external nodes becomes small. For fully connected networks the probability distribution becomes uniform at the critical point. For star networks, on the other hand, we show that the equilibrium distribution splits in two peaks, reflecting the two possible states of the central node. We obtain approximate analytical solutions for the equilibrium distribution that clarify the role of the central node in the process. We show that the network topology also affects the time scale of oscillations in single realizations of the dynamics, which are much faster for the star network. Finally, extending the analysis to two stars we compare our results with simulations in simple scale-free networks. PMID:26565294

  2. Binary dynamics on star networks under external perturbations

    Science.gov (United States)

    Moreira, Carolina A.; Schneider, David M.; de Aguiar, Marcus A. M.

    2015-10-01

    We study a binary dynamical process that is a representation of the voter model with two candidates and opinion makers. The voters are represented by nodes of a network of social contacts with internal states labeled 0 or 1 and nodes that are connected can influence each other. The network is also perturbed by opinion makers, a set of external nodes whose states are frozen in 0 or 1 and that can influence all nodes of the network. The quantity of interest is the probability of finding m nodes in state 1 at time t . Here we study this process on star networks, which are simple representations of hubs found in complex systems, and compare the results with those obtained for networks that are fully connected. In both cases a transition from disordered to ordered equilibrium states is observed as the number of external nodes becomes small. For fully connected networks the probability distribution becomes uniform at the critical point. For star networks, on the other hand, we show that the equilibrium distribution splits in two peaks, reflecting the two possible states of the central node. We obtain approximate analytical solutions for the equilibrium distribution that clarify the role of the central node in the process. We show that the network topology also affects the time scale of oscillations in single realizations of the dynamics, which are much faster for the star network. Finally, extending the analysis to two stars we compare our results with simulations in simple scale-free networks.

  3. Gemini optical observations of binary millisecond-pulsars

    CERN Document Server

    Testa, V; Pallanca, C; Corongiu, A; Ferraro, F R

    2015-01-01

    Milli-second pulsars (MSPs) are rapidly spinning neutron stars, with spin periods P_s <= 10 ms, which have been most likely spun up after a phase of matter accretion from a companion star. In this work we present the results of the search for the companion stars of four binary milli-second pulsars, carried out with archival data from the Gemini South telescope. Based upon a very good positional coincidence with the pulsar radio coordinates, we likely identified the companion stars to three MSPs, namely PSRJ0614-3329 (g=21.95 +- 0.05), J1231-1411 (g=25.40 +-0.23), and J2017+0603 (g=24.72 +- 0.28). For the last pulsar (PSRJ0613-0200) the identification was hampered by the presence of a bright star (g=16 +- 0.03) at \\sim 2" from the pulsar radio coordinates and we could only set 3-sigma upper limits of g=25.0, r= 24.3, and i= 24.2 on the magnitudes of its companion star. The candidate companion stars to PSRJ0614-3329, J1231-1411, and J2017+0603 can be tentatively identified as He white dwarfs (WDs) on the bas...

  4. Binary dynamics on star networks under external perturbations

    CERN Document Server

    Moreira, Carolina A

    2015-01-01

    We study a binary dynamical process that is a representation of the voter model with opinion makers. The process models an election with two candidates but can also describe the frequencies of a biallelic gene in a population or atoms with two spin orientations in a magnetic material. The system is represented by a network whose nodes have internal states labeled 0 or 1, and nodes that are connected can influence each other. The network is perturbed by a set of external nodes whose states are fixed in 0 or 1 and that can influence all nodes of the network. The fixed nodes play the role of opinion makers in the voter model, mutation rates in population genetics or temperature in a magnetic material. The quantity of interest is the probability $\\rho(m,t)$ that $m$ nodes are in state 1 at time $t$. Here we study this process on star networks and compare the results with those obtained for networks that are fully connected. In both cases a transition from disordered to ordered equilibrium states is observed as th...

  5. Candidate marketing takes the guessing game out of choosing employers.

    Science.gov (United States)

    Russell, Judith; Havel, Stacey

    2010-01-01

    Candidate marketing builds a foundation for relationships between employers and potential employees. Additionally, candidate marketing differentiates organizations in the marketplace. Organizations using candidate marketing to communicate the employer brand can expect a higher quality of candidates, and new employees are better prepared for the work environment and culture. Today, organizations can use a variety of integrated tools and techniques to communicate and build relationships with candidates. Candidate marketing demonstrates an organization's willingness towards transparency, and ability to invite open conversations between candidates and members of the organizations. PMID:20672542

  6. BEER analysis of Kepler and CoRoT light curves. III. Spectroscopic confirmation of seventy new beaming binaries discovered in CoRoT light curves

    Science.gov (United States)

    Tal-Or, L.; Faigler, S.; Mazeh, T.

    2015-08-01

    Context. The BEER algorithm searches stellar light curves for the BEaming, Ellipsoidal, and Reflection photometric modulations that are caused by a short-period companion. These three effects are typically of very low amplitude and can mainly be detected in light curves from space-based photometers. Unlike eclipsing binaries, these effects are not limited to edge-on inclinations. Aims: Applying the algorithm to wide-field photometric surveys such as CoRoT and Kepler offers an opportunity to better understand the statistical properties of short-period binaries. It also widens the window for detecting intrinsically rare systems, such as short-period brown-dwarf and massive-planetary companions to main-sequence stars. Methods: Applying the search to the first five long-run center CoRoT fields, we identified 481 non-eclipsing candidates with periodic flux amplitudes of 0.5-87 mmag. Optimizing the Anglo-Australian-Telescope pointing coordinates and the AAOmega fiber-allocations with dedicated softwares, we acquired six spectra for 231 candidates and seven spectra for another 50 candidates in a seven-night campaign. Analysis of the red-arm AAOmega spectra, which covered the range of 8342-8842 Å, yielded a radial-velocity precision of ~1 km s-1. Spectra containing lines of more than one star were analyzed with the two-dimensional correlation algorithm TODCOR. Results: The measured radial velocities confirmed the binarity of seventy of the BEER candidates - 45 single-line binaries, 18 double-line binaries, and 7 diluted binaries. We show that red giants introduce a major source of false candidates and demonstrate a way to improve BEER's performance in extracting higher fidelity samples from future searches of CoRoT light curves. The periods of the confirmed binaries span a range of 0.3-10 days and show a rise in the number of binaries per ΔlogP toward longer periods. The estimated mass ratios of the double-line binaries and the mass ratios assigned to the single

  7. Formation and evolution of X-ray binaries

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We review recent progress in theoretical understanding of X-ray binaries,which has largely been driven by new observations.We select several topics including formation of compact low-mass X-ray binaries,the evolutionary connection between low-mass X-ray binaries and binary and millisecond radio pulsars,and ultraluminous X-ray sources,to illustrate the interplay between theories and observations.

  8. A Luminous Gamma-ray Binary in the Large Magellanic Cloud

    CERN Document Server

    Corbet, R H D; Coe, M J; Coley, J B; Dubus, G; Edwards, P G; Martin, P; McBride, V A; Stevens, J; Strader, J; Townsend, L J; Udalski, A

    2016-01-01

    Gamma-ray binaries consist of a neutron star or a black hole interacting with a normal star to produce gamma-ray emission that dominates the radiative output of the system. Only a handful of such systems have been previously discovered, all within our Galaxy. Here we report the discovery with the Fermi Large Area Telescope (LAT) of a luminous gamma-ray binary in the Large Magellanic Cloud from a search for periodic modulation in all sources in the third Fermi LAT catalog. This is the first such system to be found outside the Milky Way. The system has an orbital period of 10.3 days and is associated with a massive O5III star located in the supernova remnant DEM L241, previously identified as the candidate high-mass X-ray binary (HMXB) CXOU J053600.0-673507. X-ray and radio emission are also modulated on the 10.3 day period, but are in anti-phase with the gamma-ray modulation. Optical radial velocity measurements suggest that the system contains a neutron star. The source is significantly more luminous than sim...

  9. A LARGE SYSTEMATIC SEARCH FOR CLOSE SUPERMASSIVE BINARY AND RAPIDLY RECOILING BLACK HOLES

    International Nuclear Information System (INIS)

    We have carried out a systematic search for subparsec supermassive black hole (BH) binaries among z ∼ 1000 km s–1. This method also yields candidates for rapidly recoiling BHs. Of the 88 candidates, several were previously reported in the literature. We found a correlation between the peak offset and skewness of the broad Hβ profiles, suggesting a common physical explanation for these profiles. We carried out follow-up spectroscopic observations of 68 objects to search for changes in the peak velocities of the Hβ lines. We measured statistically significant changes in 14 objects, with implied accelerations between –120 and +120 km s–1 yr–1. Interpreting the offset broad emission lines as signatures of supermassive binaries is subject to many caveats. Many more follow-up observations over a long temporal baseline are needed to characterize the variability pattern of the broad lines and test that it is consistent with orbital motion. The possibility that some of the objects in this sample are rapidly recoiling BHs remains open.

  10. An extremely fast halo hot subdwarf star in a wide binary system

    CERN Document Server

    Németh, Péter; Irrgang, Andreas; Geier, Stephan; Fürst, Felix; Kupfer, Thomas; Heber, Ulrich

    2016-01-01

    New spectroscopic observations of the halo hyper-velocity star candidate SDSS J121150.27+143716.2 ($V=17.92$ mag) revealed a cool companion to the hot subdwarf primary. The components have a very similar radial velocity and their absolute luminosities are consistent with the same distance, confirming the physical nature of the binary, which is the first double-lined hyper-velocity candidate. Our spectral decomposition of the Keck/ESI spectrum provided an sdB+K3V pair, analogous to many long-period subdwarf binaries observed in the Galactic disk. We found the subdwarf atmospheric parameters: $T_{\\rm eff}=30\\,600\\pm500$ K, $\\log{g}=5.57\\pm0.06$ cm s$^{-2}$ and He abundance $\\log(n{\\rm He}/n{\\rm H})=-3.0\\pm0.2$. Oxygen is the most abundant metal in the hot subdwarf atmosphere, and Mg and Na lines are the most prominent spectral features of the cool companion, consistent with a metallicity of $[{\\rm Fe}/{\\rm H}]=-1.3$. The non-detection of radial velocity variations suggest the orbital period to be a few hundred ...

  11. Binary Solid-Liquid Phase Equilibria

    Science.gov (United States)

    Ellison, Herbert R.

    1978-01-01

    Indicates some of the information that may be obtained from a binary solid-liquid phase equilibria experiment and a method to write a computer program that will plot an ideal phase diagram to which the experimental results may be compared. (Author/CP)

  12. The Environment of Binary Nuetron Star Mergers

    Science.gov (United States)

    Wiggins, Brandon

    2016-04-01

    In addition to detections by LIGO, binary neutron star mergers may be detected via luminous interaction with surrounding interstellar media. Upcoming observations including the VLASS survey may be able to detect such interactions and offer constraints on the binary neutron star merger rate. In this talk, I will present the results of cosmological simulations of a cluster of galaxies followed down to redshift 0. Our calculation includes star formation from which we infer a supernova and binary neutron star production rate. Using pre-existing models of neutron star binaries, we follow the positions of neutron star pairs in the cluster potential throughout cosmic time allowing us to identify regions in which neutron stars merge. We present statistics of many Monte Carlo instances of nuetron star pairs and trajectories allowing us to constrain the approximate fraction of neutron stars merging in dense gas. Our work has implications for R-process enrichment of galaxies in addition to predicting electromagnetic counterparts to gravitational wave detections of neutron star mergers.

  13. The Evolution of Relativistic Binary Progenitor Systems

    CERN Document Server

    Francischelli, G J; Brown, G E

    2001-01-01

    Relativistic binary pulsars, such as B1534+12 and B1913+16 are characterized by having close orbits with a binary separation of ~ 3 R_\\sun. The progenitor of such a system is a neutron star, helium star binary. The helium star, with a strong stellar wind, is able to spin up its compact companion via accretion. The neutron star's magnetic field is then lowered to observed values of about 10^{10} Gauss. As the pulsar lifetime is inversely proportional to its magnetic field, the possibility of observing such a system is, thus, enhanced by this type of evolution. We will show that a nascent (Crab-like) pulsar in such a system can, through accretion-braking torques (i.e. the "propeller effect") and wind-induced spin-up rates, reach equilibrium periods that are close to observed values. Such processes occur within the relatively short helium star lifetimes. Additionally, we find that the final outcome of such evolutionary scenarios depends strongly on initial parameters, particularly the initial binary separation a...

  14. 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)

  15. A Binary Teetering on the Edge

    Science.gov (United States)

    Motl, P. M.; D'Souza, M. C. R.; Tohline, J. E.; Frank, J.

    2005-05-01

    We present a fully three-dimensional hydrodynamical simulation of Roche lobe overflow in a binary near the stability boundary. This boundary separates evolutionary branches that correspond to either an accelerating mass transfer rate leading eventually to merger through tidal instability or to a decaying mass transfer rate as the orbit expands. The binary begins with a mass ratio of 0.4 (ratio of donor to accretor mass) and is initially assumed to be rotating synchronously. We treat the stellar components as simple polytropic fluids characterized by a polytropic index, n = 3/2. As the donor overflows its Roche lobe, the mass transfer rate initially accelerates before stabilizing and eventually dropping over a timescale of tens of orbits. We also note that for this particular binary, the accretion stream impacts on the surface of the donor rather than forming an accretion disk. This simulation allows us to measure the efficiency with which the accretion stream spins up the accretor in this "direct impact" scenario and the degree to which angular momentum is transfered back to the binary orbit via the tidal field.

  16. Pedestrian Detection Using Gradient Local Binary Patterns

    Science.gov (United States)

    Jiang, Ning; Xu, Jiu; Goto, Satoshi

    In recent years, local pattern based features have attracted increasing interest in object detection and recognition systems. Local Binary Pattern (LBP) feature is widely used in texture classification and face detection. But the original definition of LBP is not suitable for human detection. In this paper, we propose a novel feature named gradient local binary patterns (GLBP) for human detection. In this feature, original 256 local binary patterns are reduced to 56 patterns. These 56 patterns named uniform patterns are used for generating a 56-bin histogram. And gradient value of each pixel is set as the weight which is always same in LBP based features in histogram calculation to computing the values in 56 bins for histogram. Experiments are performed on INRIA dataset, which shows the proposal GLBP feature is discriminative than histogram of orientated gradient (HOG), Semantic Local Binary Patterns (S-LBP) and histogram of template (HOT). In our experiments, the window size is fixed. That means the performance can be improved by boosting methods. And the computation of GLBP feature is parallel, which make it easy for hardware acceleration. These factors make GLBP feature possible for real-time pedestrian detection.

  17. 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.

  18. 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. PMID:25910104

  19. Numerical simulations of compact object binaries

    OpenAIRE

    Pfeiffer, Harald P.

    2012-01-01

    Coalescing compact object binaries consisting of black holes and/or Neutron stars are a prime target for ground-based gravitational wave detectors. This article reviews the status of numerical simulations of these systems, with an emphasis on recent progress.

  20. PARTICLE SEGREGATION IN FLUIDIZED BINARY-MIXTURES

    NARCIS (Netherlands)

    HOFFMANN, AC; JANSSEN, LPBM

    1993-01-01

    The particle segregation in fluidised beds consisting of different types of binary mixtures is shown to be governed by the same particle transport processes. The segregation behaviour of both ''different-density mixtures'' and ''equal-density mixtures'', two types of system which until now largely h

  1. Planetary nebula progenitors that swallow binary systems

    CERN Document Server

    Soker, Noam

    2015-01-01

    I propose that some irregular `messy' planetary nebulae owe their morphologies to triple-stellar evolution where tight binary systems are tidally and frictionally destroyed inside the envelope of asymptotic giant branch (AGB) stars. The tight binary system might breakup with one star leaving the system. In an alternative evolution, one of the stars of the brook-up tight binary system falls toward the AGB envelope with low specific angular momentum, and drowns in the envelope. In a different type of destruction process the drag inside the AGB envelope causes the tight binary system to merge. This releases gravitational energy within the AGB envelope, leading to a very asymmetrical envelope ejection, with an irregular and `messy' planetary nebula as a descendant. The evolution of the triple-stellar system before destruction can be in a full common envelope evolution (CEE) or in a grazing envelope evolution (GEE). Both before and after destruction the system might lunch pairs of opposite jets. One pronounced sig...

  2. Locating Restricted Facilities on Binary Maps

    CERN Document Server

    Andreica, Mugurel Ionut; Andreica, Madalina Ecaterina

    2008-01-01

    In this paper we consider several facility location problems with applications to cost and social welfare optimization, when the area map is encoded as a binary (0,1) mxn matrix. We present algorithmic solutions for all the problems. Some cases are too particular to be used in practical situations, but they are at least a starting point for more generic solutions.

  3. Cassini states for black hole binaries

    Science.gov (United States)

    Correia, Alexandre C. M.

    2016-03-01

    Cassini states correspond to the equilibria of the spin axis of a body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black hole binary systems based on a Hamiltonian formalism. In absence of dissipation, the problem is integrable and it is easy to identify all possible trajectories for the spin for a given value of the total angular momentum. As the system collapses due to radiation reaction, the Cassini states are shifted to different positions, which modifies the dynamics around them. This is why the final spin distribution may differ from the initial one. Our method provides a simple way of predicting the distribution of the spin of black hole binaries at the end of the inspiral phase.

  4. 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. PMID:26753630

  5. Eclipsing Binaries with the Kepler Mission

    Science.gov (United States)

    Prsa, Andrej; Kepler Eclipsing Binary Working Group

    2012-05-01

    Kepler has revolutionized the eclipsing binary field by providing us essentially uninterrupted data of unprecedented quality. Out of 160,000 targets, we detected over 2500 eclipsing binaries. These range in orbital periods from as short as 0.3 days, all the way to several years, and encompass stellar types across the H-R diagram. In this talk I will present the collaborative effort of the Kepler Eclipsing Binary Working Group to study and characterize these systems on a statistical level: their distribution in periods, galactic latitude, spectral type, fundamental stellar properties and multiplicity as evidenced by eclipse timing variations. I will further show the gems that have sprung from this sample, which were modeled and interpreted to reveal intrinsically pulsating components, runaway encounters with massive tertiaries, stellar objects that populate the lowest end of the main sequence and circumbinary planets. I will critically review and discuss the causes of data systematics and detrending, and introduce a novel algorithm to classify light curves into morphological types using Locally Linear Embedding. Finally, I will touch on the dark side of eclipsing binaries as the primary cause of false positives in extrasolar planet detections with Kepler.

  6. Spin frequency distributions of binary millisecond pulsars

    NARCIS (Netherlands)

    A. Papitto; D.F. Torres; N. Rea; T.M. Tauris

    2014-01-01

    Rotation-powered millisecond radio pulsars have been spun up to their present spin period by a 108−109 yr long X-ray-bright phase of accretion of matter and angular momentum in a low-to-intermediate mass binary system. Recently, the discovery of transitional pulsars that alternate cyclically between

  7. Short-timescale variability in cataclysmic binaries

    International Nuclear Information System (INIS)

    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

  8. Cassini states for black-hole binaries

    CERN Document Server

    Correia, Alexandre C M

    2016-01-01

    Cassini states correspond to equilibria of the spin axis of a celestial body when its orbit is perturbed. They were initially described for planetary satellites, but the spin axes of black-hole binaries also present this kind of equilibria. In previous works, Cassini states were reported as spin-orbit resonances, but actually the spin of black-hole binaries is in circulation and there is no resonant motion. Here we provide a general description of the spin dynamics of black-hole binary systems based on a Hamiltonian formalism. In absence of dissipation the problem is integrable and it is easy to identify all possible trajectories for the spin for a given value of the total angular momentum. As the system collapses due to radiation reaction, the Cassini states are shifted to different positions, which modifies the dynamics around them. This is why the final spin distribution may differ from the initial one. Our method provides a simple way of predicting the distribution of the spin of black-hole binaries at th...

  9. Supermassive Black Hole Binaries: The Search Continues

    CERN Document Server

    Bogdanovic, Tamara

    2014-01-01

    Gravitationally bound supermassive black hole binaries (SBHBs) are thought to be a natural product of galactic mergers and growth of the large scale structure in the universe. They however remain observationally elusive, thus raising a question about characteristic observational signatures associated with these systems. In this conference proceeding I discuss current theoretical understanding and latest advances and prospects in observational searches for SBHBs.

  10. 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

  11. Generating quality tetrahedral meshes from binary volumes

    DEFF Research Database (Denmark)

    Hansen, Mads Fogtmann; Bærentzen, Jakob Andreas; Larsen, Rasmus

    2010-01-01

    use these measures to generate high quality meshes from signed distance maps. This paper also describes an approach for computing (smooth) signed distance maps from binary volumes as volumetric data in many cases originate from segmentation of objects from imaging techniques such as CT, MRI, etc. The...

  12. Binary pulsars as dark-matter probes

    CERN Document Server

    Pani, Paolo

    2015-01-01

    During the motion of a binary pulsar around the galactic center, the pulsar and its companion experience a wind of dark-matter particles that can affect the orbital motion through dynamical friction. We show that this effect produces a characteristic seasonal modulation of the orbit and causes a secular change of the orbital period whose magnitude can be well within the astonishing precision of various binary-pulsar observations. Our analysis is valid for binary systems with orbital period longer than a day. By comparing this effect with pulsar-timing measurements, it is possible to derive model-independent upper bounds on the dark-matter density at different distances $D$ from the galactic center. For example, the precision timing of J1713+0747 imposes $\\rho_{\\rm DM}\\lesssim 10^5\\,{\\rm GeV/cm}^3$ at $D\\approx7\\,{\\rm kpc}$. The detection of a binary pulsar at $D\\lesssim 10\\,{\\rm pc}$ could provide stringent constraints on dark-matter halo profiles and on growth models of the central black hole. The Square Kil...

  13. Testing the Binary Trigger Hypothesis in FUors

    CERN Document Server

    Green, Joel D; Rizzuto, Aaron C; Ireland, Michael J; Dupuy, Trent J; Mann, Andrew W; Kuruwita, Rajika

    2016-01-01

    We present observations of three FU Orionis objects (hereafter, FUors) with nonredundant aperture-mask interferometry (NRM) at 1.59 um and 2.12 um that probe for binary companions on the scale of the protoplanetary disk that feeds their accretion outbursts. We do not identify any companions to V1515 Cyg or HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the diffraction limit (rho = 58.3 +/- 1.4 mas or 30 +/- 5 AU) and currently much fainter than the outbursting star (delta(K') = 3.34 +/- 0.10 mag). Given the flux excess of the outbursting star, we estimate that the mass of the companion (M ~ 0.25 Msun) is similar to or slightly below that of the FUor itself, and therefore it resembles a typical T Tauri binary system. Our observations only achieve contrast limits of delta(K') ~ 4 mag, and hence we are only sensitive to companions that were near or above the pre-outburst luminosity of the FUors. It remains plausible that FUor outbursts could be tied to the presence of a close binary ...

  14. Constraining Binary Stellar Evolution With Pulsar Timing

    Science.gov (United States)

    Ferdman, Robert D.; Stairs, I. H.; Backer, D. C.; Burgay, M.; Camilo, F.; D'Amico, N.; Demorest, P.; Faulkner, A.; Hobbs, G.; Kramer, M.; Lorimer, D. R.; Lyne, A. G.; Manchester, R.; McLaughlin, M.; Nice, D. J.; Possenti, A.

    2006-06-01

    The Parkes Multibeam Pulsar Survey has yielded a significant number of very interesting binary and millisecond pulsars. Two of these objects are part of an ongoing timing study at the Green Bank Telescope (GBT). PSR J1756-2251 is a double-neutron star (DNS) binary system. It is similar to the original Hulse-Taylor binary pulsar system PSR B1913+16 in its orbital properties, thus providing another important opportunity to test the validity of General Relativity, as well as the evolutionary history of DNS systems through mass measurements. PSR J1802-2124 is part of the relatively new and unstudied "intermediate-mass" class of binary system, which typically have spin periods in the tens of milliseconds, and/or relatively massive (> 0.7 solar masses) white dwarf companions. With our GBT observations, we have detected the Shapiro delay in this system, allowing us to constrain the individual masses of the neutron star and white dwarf companion, and thus the mass-transfer history, in this unusual system.

  15. Performance of binary FSK data transmission systems

    Science.gov (United States)

    Batson, B. H.

    1973-01-01

    Matched-filter detection of binary signals is discussed in terms of the probability of bit error. The equations for the probability of error are derived for coherent phase shift keying, and coherent frequency shift keying (FSK). Suboptimum detection of FSK signals is also discussed for discriminators.

  16. BINARY WAVELET TRANSFORM FOR IMAGE REPRESENTATION

    Directory of Open Access Journals (Sweden)

    ASHOK.M

    2011-08-01

    Full Text Available The MRA (Multi resolution analysis for an image provides specific information localized in space or frequency domain .In this paper an efficient representation of the visual information is presented using Binary wavelet Transform for both color and gray level image. Analytical results shows that this method proves to be more efficient in representing the visual information than the earlier

  17. A semantic constraint on binary determiners

    OpenAIRE

    Zuber, Richard

    2009-01-01

    Abstract A type $${\\langle{1^2, 1}\\rangle}$$ quantifier F is symmetric iff F(X, X)(Y) = F(Y, Y)(X). It is shown that quantifiers denoted by irreducible binary determiners in natural languages are both conservative and symmetric and not only conservative.

  18. Orbits of Ten Visual Binary Stars

    Institute of Scientific and Technical Information of China (English)

    B.Novakovi(c)

    2007-01-01

    We present the orbits of ten visual binary stars:WDS 01015+6922.WDS 01424-0645,WDS 01461+6349,WDS 04374-0951,WDS 04478+5318,WDS 05255-0033,WDS 05491+6248,WDS 06404+4058,WDS 07479-1212,and WDS 18384+0850.We have also determined their masses,dynamical parallaxes and ephemerides.

  19. 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-m...

  20. Cluster selection in binary nuclear models

    CERN Document Server

    Buck, B; Pérez, S M

    2000-01-01

    We present a simple prescription for selecting the cluster and core in a binary cluster-model description of a nucleus. The prescription reproduces the cluster-core combinations used in earlier successful applications of the model, predicts others, and extends the good agreement previously found with observed B(E2; 2 sup + -> 0 sup +) values of actinide nuclei. Refs. 31 (author)

  1. Merging Compact Binaries in Hierarchical Triple Systems: Resonant Excitation of Binary Eccentricity

    CERN Document Server

    Liu, Bin; Yuan, Ye-Fei

    2015-01-01

    The merging of compact binaries play an important role in astrophysical context. The gravitational waves takes the angular momentum off the merging binary, which makes the orbit of the inner binary shrink. In this work, we study the secular dynamics of merging binary with a small perturber in hierarchical triple systems. From our numerical calculations, we find that the triple system goes through a resonant state between the apsidal precession rates of two orbits during the orbital decay, and the eccentricity of the inner orbit is excited, as well as the corresponding gravita- tional wave frequency. Our numerical results could be understood under the linear approximation of small orbital eccentricities and coplanar configuration. Especially, the resonant condition and the excited eccentricity can be estimated analytically.

  2. Infalling clouds on to supermassive black hole binaries - II. Binary evolution and the final parsec problem

    CERN Document Server

    Goicovic, Felipe G; Cuadra, Jorge; Stasyszyn, Federico

    2016-01-01

    The formation of massive black hole binaries (MBHBs) is an unavoidable outcome of galaxy evolution via successive mergers. However, the mechanism that drives their orbital evolution from parsec separations down to the gravitational wave (GW) dominated regime is poorly understood and their final fate is still unclear. If such binaries are embedded in gas-rich and turbulent environments, as observed in remnants of galaxy mergers, the interaction with gas clumps (such as molecular clouds) may efficiently drive their orbital evolution. Using numerical simulations, we test this hypothesis by studying the dynamical evolution of an equal-mass, circular MBHB accreting infalling molecular clouds. We investigate different orbital configurations, modelling a total of 13 systems to explore different possible pericentre distances and relative inclinations of the cloud-binary encounter. We show that the evolution of the binary orbit is dominated by the exchange of angular momentum through gas accretion during the first sta...

  3. Radio evidence for binary super massive black holes

    Science.gov (United States)

    Ekers, R. D.

    2016-02-01

    I present examples of radio AGN with binary nuclei which provide the direct radio evidence for binary Super Massive Black Holes (SMBH) driving the AGN activity. There is also other evidence for distorted radio morphology and periodic variability which may indicate the presence of a second (inactive) SMBH. Finally I enumerate a number of possible radio tracers for the binary SMBH merger events.

  4. Kepler Eclipsing Binary Stars. VIII. Identification of False Positive Eclipsing Binaries and Re-extraction of New Light Curves

    CERN Document Server

    Abdul-Masih, Michael; Conroy, Kyle; Bloemen, Steven; Boyajian, Tabetha; Doyle, Laurance R; Johnston, Cole; Kostov, Veselin; Latham, David W; Matijevic, Gal; Shporer, Avi; Southworth, John

    2016-01-01

    The Kepler Mission has provided unprecedented, nearly continuous photometric data of $\\sim$200,000 objects in the $\\sim$105 deg$^{2}$ field of view from the beginning of science operations in May of 2009 until the loss of the second reaction wheel in May of 2013. The Kepler Eclipsing Binary Catalog contains information including but not limited to ephemerides, stellar parameters and analytical approximation fits for every known eclipsing binary system in the Kepler Field of View. Using Target Pixel level data collected from Kepler in conjunction with the Kepler Eclipsing Binary Catalog, we identify false positives among eclipsing binaries, i.e. targets that are not eclipsing binaries themselves, but are instead contaminated by eclipsing binary sources nearby on the sky and show eclipsing binary signatures in their light curves. We present methods for identifying these false positives and for extracting new light curves for the true source of the observed binary signal. For each source, we extract three separa...

  5. A decoding method of an n length binary BCH code through (n + 1n length binary cyclic code

    Directory of Open Access Journals (Sweden)

    TARIQ SHAH

    2013-09-01

    Full Text Available For a given binary BCH code Cn of length n = 2 s - 1 generated by a polynomial of degree r there is no binary BCH code of length (n + 1n generated by a generalized polynomial of degree 2r. However, it does exist a binary cyclic code C (n+1n of length (n + 1n such that the binary BCH code Cn is embedded in C (n+1n . Accordingly a high code rate is attained through a binary cyclic code C (n+1n for a binary BCH code Cn . Furthermore, an algorithm proposed facilitates in a decoding of a binary BCH code Cn through the decoding of a binary cyclic code C (n+1n , while the codes Cn and C (n+1n have the same minimum hamming distance.

  6. A LARGE SYSTEMATIC SEARCH FOR CLOSE SUPERMASSIVE BINARY AND RAPIDLY RECOILING BLACK HOLES

    Energy Technology Data Exchange (ETDEWEB)

    Eracleous, Michael [Department of Astronomy and Astrophysics and Center for Gravitational Wave Physics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16803 (United States); Boroson, Todd A. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Halpern, Jules P.; Liu Jia [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027-6601 (United States)

    2012-08-01

    We have carried out a systematic search for subparsec supermassive black hole (BH) binaries among z {approx}< 0.7 Sloan Digital Sky Survey quasars. These are predicted by models of supermassive BH and host galaxy coevolution, therefore their census and population properties constitute an important test of these models. In our working hypothesis, one of the two BHs accretes at a much higher rate than the other and carries with it the only broad emission line region of the system, making the system analogous to a single-lined spectroscopic binary star. Accordingly, we used spectroscopic principal component analysis to search for broad H{beta} emission lines that are displaced from the quasar rest frame by |{Delta} v| {approx}> 1000 km s{sup -1}. This method also yields candidates for rapidly recoiling BHs. Of the 88 candidates, several were previously reported in the literature. We found a correlation between the peak offset and skewness of the broad H{beta} profiles, suggesting a common physical explanation for these profiles. We carried out follow-up spectroscopic observations of 68 objects to search for changes in the peak velocities of the H{beta} lines. We measured statistically significant changes in 14 objects, with implied accelerations between -120 and +120 km s{sup -1} yr{sup -1}. Interpreting the offset broad emission lines as signatures of supermassive binaries is subject to many caveats. Many more follow-up observations over a long temporal baseline are needed to characterize the variability pattern of the broad lines and test that it is consistent with orbital motion. The possibility that some of the objects in this sample are rapidly recoiling BHs remains open.

  7. Candidate Species Selection: Cultural and Photosynthetic Aspects

    Science.gov (United States)

    Mitchell, C. A.

    1982-01-01

    Cultural information is provided for a data base that will be used to select candidate crop species for a controlled ecological life support system (CELSS). Lists of food crops which will satisfy most nutritional requirements of humans and also fit within the scope of cultural restrictions that logically would apply to a closed, regenerating system were generated. Cultural and environmental conditions that will allow the most rapid production of edible biomass from candidate species in the shortest possible time are identified. Cultivars which are most productive in terms of edible biomass production by (CE) conditions, and which respond to the ever-closed approach to optimization realized by each shortened production cycle are selected. The experimental approach with lettuce was to grow the crop hydroponically in a growth chamber and to manipulate such variables as light level and duration, day/night temperature, and nutrient form and level in the solution culture.

  8. New drug candidates in tuberculosis treatment

    Directory of Open Access Journals (Sweden)

    Begüm Evranos Aksöz

    2014-12-01

    makes them quit the treatment. From these problems emerges the need for development of effective new drugs, with smaller duration of therapy, less side effects and without the problem of resistance. After a long period such as 40 years, a new drug molecule bedaquiline was approved in December 2012 by FDA while the drug was in phase II research. Bedaquiline will be used in multidrug resistant tuberculosis therapy. When the chemical structures of bedaquilline and other candidate drugs were examined, the structures such as diarylquinoline, oxazolidinone, nitroimidazole, ethylenediamine drew attention. These common structures will be directive in designing new molecules. In this review, bedaquiline and other candidate drug molecules such as sutezolide, linezolide, PA-824, delamanide, rifapentine, gatifloxacin, moxifloxacin, BTZ-043, TBA-354, CPZEN-45, DC-159a, Q201, SQ-609, SQ-641 were mentioned.

  9. Optical Nova Candidate in M 31

    Science.gov (United States)

    Henze, M.; Burwitz, V.; Pietsch, W.; Updike, A.; Milne, P.; Williams, G.; Hartmann, D. H.

    2008-06-01

    We report the discovery of an optical nova candidate in M 31 on two 11x60s stacked R filter CCD images obtained with the robotic 60cm telescope with an E2V CCD (2kx2k) of the Livermore Optical Transient Imaging System (Super-LOTIS, located at Steward Observatory, Kitt Peak, Arizona, USA). The object was first detected on 2008 June 14.46 and 16.46 UT with respective magnitudes of 18.0 and 17.7. The position for the nova candidate is RA = 00h42m37.72s, Dec = +41d12'30.0"(J2000, accuracy of 0.3"), which is 1'14" west and 3'39" south of the core of M 31. All magnitudes given are obtained from a photometric solution using R magnitudes of the Local Group Survey M 31 catalogue (Massey et al.

  10. Spectroscopic follow up of Kepler planet candidates

    DEFF Research Database (Denmark)

    Latham..[], D. W.; Cochran, W. D.; Marcy, G.W.;

    2010-01-01

    Spectroscopic follow-up observations play a crucial role in the confirmation and characterization of transiting planet candidates identified by Kepler. The most challenging part of this work is the determination of radial velocities with a precision approaching 1 m/s in order to derive masses from...... spectroscopic orbits. The most precious resource for this work is HIRES on Keck I, to be joined by HARPS-North on the William Herschel Telescope when that new spectrometer comes on line in two years. Because a large fraction of the planet candidates are in fact stellar systems involving eclipsing stars and not...... planets, our strategy is to start with reconnaissance spectroscopy using smaller telescopes, to sort out and reject as many of the false positives as possible before going to Keck. During the first Kepler observing season in 2009, more than 100 nights of telescope time were allocated for this work, using...

  11. Binary Disk interaction II: Gap-Opening criteria for unequal mass binaries

    CERN Document Server

    del Valle, Luciano

    2013-01-01

    We study the interaction between an unequal mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a SMBH binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts onto the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong non-axisymmetric density perturbation that is produced in the disk, as response to the presence of the binary. Using SPH numerical simulations we tested two gap-opening criterion, one that assumes that the geometry of the density perturbation is an ellipsoid/thick-spirals and another that assumes a geometry of flat-spirals for the density perturbation. We find that the flat-spirals gap opening criterion successfully predicts which simulations will hav...

  12. Binaries migrating in a gaseous disk: Where are the Galactic center binaries?

    CERN Document Server

    Baruteau, C; Lin, D N C

    2010-01-01

    The massive stars in the Galactic center inner arcsecond share analogous properties with the so-called Hot Jupiters. Most of these young stars have highly eccentric orbits, and were probably not formed in-situ. It has been proposed that these stars acquired their current orbits from the tidal disruption of compact massive binaries scattered toward the proximity of the central supermassive black hole. Assuming a binary star formed in a thin gaseous disk beyond 0.1 pc from the central object, we investigate the relevance of disk-satellite interactions to harden the binding energy of the binary, and to drive its inward migration. A massive, equal-mass binary star is found to become more tightly wound as it migrates inwards toward the central black hole. The migration timescale is very similar to that of a single-star satellite of the same mass. The binary's hardening is caused by the formation of spiral tails lagging the stars inside the binary's Hill radius. We show that the hardening timescale is mostly determ...

  13. Reducing stigma and discrimination: Candidate interventions

    OpenAIRE

    Kassam Aliya; Brohan Elaine; Thornicroft Graham; Lewis-Holmes Elanor

    2008-01-01

    Abstract This paper proposes that stigma in relation to people with mental illness can be understood as a combination of problems of knowledge (ignorance), attitudes (prejudice) and behaviour (discrimination). From a literature review, a series of candidate interventions are identified which may be effective in reducing stigmatisation and discrimination at the following levels: individuals with mental illness and their family members; the workplace; and local, national and international. The ...

  14. Tantalum oxide coatings as candidate environmental barriers

    OpenAIRE

    Moldovan, Monica; Weyant, C. M.; Johnson, D. Lynn; Faber, K. T.

    2004-01-01

    Tantalum (Ta) oxide, due to its high-temperature capabilities and thermal expansion coefficient similar to silicon nitride, is a promising candidate for environmental barriers for silicon (Si) nitride-based ceramics. This paper focuses on the development of plasma-sprayed Ta oxide as an environmental barrier coating for silicon nitride. Using a D-optimal design of experiments, plasma-spray processing variables were optimized to maximize coating density. The effect of processing variables on c...

  15. Sensitive Radio Survey of Obscured Quasar Candidates

    CERN Document Server

    Alexandroff, Rachael M; van Velzen, Sjoert; Greene, Jenny E; Strauss, Michael A

    2016-01-01

    We study the radio properties of moderately obscured quasars over a range of redshifts to understand the role of radio activity in accretion using the Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of $\

  16. Nonclinical Development of BCG Replacement Vaccine Candidates

    OpenAIRE

    Bernd Eisele; Martin Gengenbacher; Reginald Kidd; David McCown; Sheldon Morris; Steven Derrick; David Hokey; Dominick Laddy; Rosemary Chang; Megan Fitzpatrick; Leander Grode; Kamalakannan Velmurugan; Stefan H. E. Kaufmann; John Fulkerson; Brennan, Michael J.

    2013-01-01

    The failure of current Mycobacterium bovis bacille Calmette–Guérin (BCG) vaccines, given to neonates to protect against adult tuberculosis and the risk of using these live vaccines in HIV-infected infants, has emphasized the need for generating new, more efficacious and safer replacement vaccines. With the availability of genetic techniques for constructing recombinant BCG (rBCG) strains containing well-defined gene deletions or insertions, new vaccine candidates are under evaluation at both ...

  17. Optical durability testing of candidate solar mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Kennedy, C.; King, D.; Terwilliger, K.

    2000-03-24

    Durability testing of a variety of candidate solar reflector materials at outdoor test sites and in laboratory accelerated weathering chambers is the main activity within the Advanced Materials task of the Concentrated Solar Power (CSP) Program. Outdoor exposure testing (OET) at up to eight outdoor, worldwide exposure sites has been underway for several years. This includes collaboration under the auspices of the International Energy Agency (IEA) Solar Power and Chemical Energy Systems (SolarPACES) agreement. Outdoor sites are fully instrumented in terms of monitoring meteorological conditions and solar irradiance. Candidate materials are optically characterized prior to being subjected to exposure in real and simulated weathering environments. Optical durability is quantified by periodically re-measuring hemispherical and specular reflectance as a function of exposure time. By closely monitoring the site- and time-dependent environmental stress conditions experienced by the material samples, site-dependent loss of performance may be quantified. In addition, accelerated exposure testing (AET) of these materials in parallel under laboratory-controlled conditions may permit correlating the outdoor results with AET, and subsequently predicting service lifetimes. Test results to date for a large number of candidate solar reflector materials are presented in this report. Acronyms are defined. Based upon OET and AET results to date, conclusions can be drawn about the optical durability of the candidate reflector materials. The optical durability of thin glass, thick glass, and two metallized polymers can be characterized as excellent. The all-polymeric construction, several of the aluminized reflectors, and a metallized polymer can be characterized as having intermediate durability and require further improvement, testing and evaluation, or both.

  18. Comparing Candidate Selection : A Feminist Institutionalist Approach

    OpenAIRE

    Bjarnegard, Elin; Kenny, Meryl

    2016-01-01

    This contribution evaluates the theoretical and methodological challenges ofresearching the gendered dynamics of candidate selection in comparativeperspective. It argues that comparative studies should take into account not only thegendered nature of political parties and their wider institutional context, but mustalso investigate the informal aspects of the selection process and their genderedconsequences. The article explores these dynamics by revisiting original in-depthresearch on the can...

  19. Various Approaches for Targeting Quasar Candidates

    Science.gov (United States)

    Zhang, Y.; Zhao, Y.

    2015-09-01

    With the establishment and development of space-based and ground-based observational facilities, the improvement of scientific output of high-cost facilities is still a hot issue for astronomers. The discovery of new and rare quasars attracts much attention. Different methods to select quasar candidates are in bloom. Among them, some are based on color cuts, some are from multiwavelength data, some rely on variability of quasars, some are based on data mining, and some depend on ensemble methods.

  20. MANAGEMENT OF ALLOSENSITIZED CARDIAC TRANSPLANT CANDIDATES

    OpenAIRE

    Velez, Mauricio; Johnson, Maryl R.

    2009-01-01

    Cardiac transplantation remains the best treatment in advanced heart failure patients with a high risk of death. However, an inadequate supply of donor hearts decreases the likelihood of transplantation for many patients. Ventricular assist devices (VAD) are being increasingly used as a bridge to transplant in patients who may not survive long enough to receive a heart. This expansion in VAD use has been associated with increasing rates of allosensitization in cardiac transplant candidates. A...

  1. Critical Thinking Tendencies of Music Teacher Candidates

    OpenAIRE

    Duygu PİJİ KÜÇÜK; Yusuf Barış UZUN

    2013-01-01

    In this study, determining critical thinking and education levels, which are in sub-dimensions, of music teacher candidates, determining critical thinking tendency and the relations between sub dimensions and detecting if or if not critical thinking tendency creates a difference in terms of gender, class and what type of school they graduated from are aimed. Work group composes of 274 students being educated in the Departments of Music Education GSEB of Education Faculty of Bolu Abant İzzet B...

  2. Preoperative Anxiety in Candidates for Heart Surgery

    OpenAIRE

    Fathi, Mehdi; Alavi, Seyed Mostafa; Joudi, Marjan; Joudi, Mitra; Mahdikhani, Helia; Ferasatkish, Rasool; Bakhshandeh, Houman; Jabbari Nooghabi, Mehdi

    2014-01-01

    Objective: The goal of this study was to evaluate preoperative anxiety and its predisposing factors in a group of adult patients who were candidate for any kind of heart surgery. Methods: We evaluated preoperative anxiety in 300 patients undergoing heart surgery whose ages ranged between 18-65 years. Relationship of probable demographic factors like gender, educational level, marital status, number of children, family support, opium addiction, occupational status, and left ventricular ejectio...

  3. Alcoholism and Alternative Splicing of Candidate Genes

    OpenAIRE

    Toshikazu Sasabe; Shoichi Ishiura

    2010-01-01

    Gene expression studies have shown that expression patterns of several genes have changed during the development of alcoholism. Gene expression is regulated not only at the level of transcription but also through alternative splicing of pre-mRNA. In this review, we discuss some of the evidence suggesting that alternative splicing of candidate genes such as DRD2 (encoding dopamine D2 receptor) may form the basis of the mechanisms underlying the pathophysiology of alcoholism. These reports sugg...

  4. VLT/NACO adaptive optics imaging of the TY CrA system - A fourth stellar component candidate detected

    CERN Document Server

    Chauvin, G; Beust, H; Fusco, T; Mouillet, D; Lacombe, F; Gendron, E; Rousset, G; Rouan, D; Brandner, W; Lenzen, R; Hubin, N; Hartung, M; Perrier, C

    2003-01-01

    We report the detection of a possible subsolar mass companion to the triple young system TY CrA using the NACO instrument at the VLT UT4 during its commissioning. Assuming for TY CrA a distance similar to that of the close binary system HD 176386, the photometric spectral type of this fourth stellar component candidate is consistent with an ~M4 star. We discuss the dynamical stability of this possible quadruple system as well as the possible location of dusty particles inside or outside the system.

  5. Nuclear safety in EU candidate countries

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-10-01

    Nuclear safety in the candidate countries to the European Union is a major issue that needs to be addressed in the framework of the enlargement process. Therefore WENRA members considered it was their duty to offer their technical assistance to their Governments and the European Union Institutions. They decided to express their collective opinion on nuclear safety in those candidate countries having at least one nuclear power plant: Bulgaria, the Czech Republic, Hungary, Lithuania, Romania, Slovakia and Slovenia. The report is structured as follows: A foreword including background information, structure of the report and the methodology used, General conclusions of WENRA members reflecting their collective opinion, For each candidate country, an executive summary, a chapter on the status of the regulatory regime and regulatory body, and a chapter on the nuclear power plant safety status. Two annexes are added to address the generic safety characteristics and safety issues for RBMK and VVER plants. The report does not cover radiation protection and decommissioning issues, while safety aspects of spent fuel and radioactive waste management are only covered as regards on-site provisions. In order to produce this report, WENRA used different means: For the chapters on the regulatory regimes and regulatory bodies, experts from WENRA did the work. For the chapters on nuclear power plant safety status, experts from WENRA and from French and German technical support organisations did the work. Taking into account the contents of these chapters, WENRA has formulated its general conclusions in this report.

  6. Nuclear safety in EU candidate countries

    International Nuclear Information System (INIS)

    Nuclear safety in the candidate countries to the European Union is a major issue that needs to be addressed in the framework of the enlargement process. Therefore WENRA members considered it was their duty to offer their technical assistance to their Governments and the European Union Institutions. They decided to express their collective opinion on nuclear safety in those candidate countries having at least one nuclear power plant: Bulgaria, the Czech Republic, Hungary, Lithuania, Romania, Slovakia and Slovenia. The report is structured as follows: A foreword including background information, structure of the report and the methodology used, General conclusions of WENRA members reflecting their collective opinion, For each candidate country, an executive summary, a chapter on the status of the regulatory regime and regulatory body, and a chapter on the nuclear power plant safety status. Two annexes are added to address the generic safety characteristics and safety issues for RBMK and VVER plants. The report does not cover radiation protection and decommissioning issues, while safety aspects of spent fuel and radioactive waste management are only covered as regards on-site provisions. In order to produce this report, WENRA used different means: For the chapters on the regulatory regimes and regulatory bodies, experts from WENRA did the work. For the chapters on nuclear power plant safety status, experts from WENRA and from French and German technical support organisations did the work. Taking into account the contents of these chapters, WENRA has formulated its general conclusions in this report

  7. Binary and ternary liquid metal-steam cycles for high-efficiency coal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Angelino, G.; Invernizzi, C. [University of Brescia, Brescia (Italy). Dept. of Mechanical Engineering

    2006-05-15

    Since in the use of coal the direct recourse to combined cycles is impractical, binary alkali metal steam cycles are recognized as an interesting and feasible option. Past attempts to employ metal vapour conversion cycles for power generation are surveyed. After selecting potassium and cesium as possible candidate fluids, the binary cycle is optimized taking as variables the top temperature, the number of condensation levels of the metal vapour cycle, and the characteristics of the bottoming steam cycle. At vaporization temperatures in the range of 750-850{sup o}C, metal vapour cycle efficiencies of about 20-24 per cent and binary cycle efficiencies of 57-61 per cent seem achievable. A survey of available building materials in the steel and in the super-alloy class showed that top temperatures of 800-850{sup o}C could be reached with state-of-the-art alloys. Metal vapour turbines are recognized as a key issue of binary plant design in that exhaust volume flows are very large even for a moderate turbine capacity. For a double flow solution, limiting turbine dimensions to those of existing 1500 r/min steam low pressure stages leads to metal vapour turbine capacity of 120 MW for potassium and 170 MW for cesium. Assuming that in the future, better materials will be available allowing alkali metal vaporization temperatures in the range of 1400-1500{sup o}C, a ternary solution is proposed which employs lithium, potassium, and steam as working fluids. At 1450{sup o}C top temperature, a cycle efficiency in excess of 70 per cent is attained.

  8. Double White Dwarfs as Probes of Single and Binary Star Evolution

    Science.gov (United States)

    Andrews, Jeffrey John

    2016-01-01

    As the endpoints of stars less massive than roughly eight solar masses, the population of Galactic white dwarfs (WD) contain information about complex stellar evolution processes. Associated pairs of WDs add an extra degree of leverage; both WDs must have formed and evolved together. The work presented in this dissertation uses various populations of double WDs (DWD) to constrain evolution of both single and binary stars. One example is the set of low-mass WDs with unseen WD companions, which are formed through a dynamically-unstable mass loss process called the common envelope. To work toward a quantitative understanding of the common envelope, we develop and apply a Bayesian statistical technique to identify the masses of the unseen WD companions. We provide results which can be compared to evolutionary models and hence a deeper understanding of how binary stars evolve through a common envelope. The statistical technique we develop can be applied to any population of single-line spectroscopic binaries. Binaries widely separated enough that they avoid any significant interaction independently evolve into separate WDs that can be identified in photometric and astrometric surveys. We discuss techniques for finding these objects, known as wide DWDs. We present a catalog of 142 candidate wide DWDs, combining both previously detected systems and systems we identify in our searches in the Sloan Digital Sky Survey. Having been born at the same time, the masses and cooling ages of the WDs in wide DWDs, obtained with our spectroscopic follow-up campaign can be used to constrain the initial-final mass relation, which relates a main sequence star to the mass of the WD into which it will evolve. We develop a novel Bayesian technique to interpret our data and present our resulting constraints on this relation which are particularly strong for initial masses between two and four solar masses. During this process, we identified one wide DWD, HS 2220+2146, that was peculiar since

  9. Robotic laser adaptive optics imaging of 715 Kepler exoplanet candidates using Robo-AO

    International Nuclear Information System (INIS)

    The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results from the 2012 observing season, searching for stars close to 715 Kepler planet candidate hosts. We find 53 companions, 43 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for large adaptive optics surveys. Our survey is sensitive to objects from ≈0.''15 to 2.''5 separation, with magnitude differences up to Δm ≈ 6. We measure an overall nearby-star probability for Kepler planet candidates of 7.4% ± 1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several Kepler Objects of Interest (KOIs) of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are 'coincident multiple' systems, with several transiting planets shared between the two stars. Finally, we find 98% confidence evidence that short-period giant planets are two to three times more likely than longer-period planets to be found in wide stellar binaries.

  10. White-light Flares on Close Binaries Observed with Kepler

    Science.gov (United States)

    Gao, Qing; Xin, Yu; Liu, Ji-Feng; Zhang, Xiao-Bin; Gao, Shuang

    2016-06-01

    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.

  11. Monitoring of Transient Black Hole Candidates observed in the INTEGRAL survey

    CERN Document Server

    Capitanio, F; Bird, A J; Ubertini, P; Federici, M

    2007-01-01

    The INTEGRAL/IBIS survey was performed collecting all the GPS and GCDE data together with all the available public data . The second catalogue, published in 2006 by Bird et al., is dominated by detection of 113 X-ray binaries, with 38 being high-mass and 67 low-mass. In most systems the compact object is a neutron star, but the sample also contains 4 confirmed Black Holes and 6 LMXB black hole candidates (BHC). There are also, in additional, 6 tentative associations as BHCs based simply on spectral and timing properties. In the sample of 12 sources (BHC and tentatively associated BHC) there are 7 transient sources that went into outbursts during the INTEGRAL survey observations. We present here the monitoring of the time and spectral evolution of these 7 outbursts.

  12. 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. PMID:27015470

  13. Twin Binaries: Studies of Stability, Mass Transfer, and Coalescence

    CERN Document Server

    Lombardi, James C; Dooley, Katherine L; Gearity, Kyle; Kalogera, Vassiliki; Rasio, Frederic A

    2010-01-01

    Motivated by suggestions that binaries with almost equal-mass components ("twins") play an important role in the formation of double neutron stars and may be rather abundant among binaries, we study the stability of synchronized close and contact binaries with identical components in circular orbits. In particular, we investigate the dependency of the innermost stable circular orbit on the core mass, and we study the coalescence of the binary that occurs at smaller separations. For twin binaries composed of convective main-sequence stars, subgiants, or giants with low mass cores (M_c ~0.15M), we find that stable contact configurations exist at all separations down to the Roche limit, when mass shedding through the outer Lagrangian points triggers a coalescence of the envelopes and leaves the cores orbiting in a central tight binary. We discuss the implications of our results to the formation of binary neutron stars.

  14. Template Mode Hierarchies for Binary Black Hole Mergers

    CERN Document Server

    Healy, James; Pekowsky, Larne; Shoemaker, Deirdre

    2013-01-01

    Matched filtering is a popular data analysis framework used to search for gravitational wave signals emitted by compact object binaries. The templates used in matched filtering searches are constructed predominantly from the quadrupolar mode because this mode is the energetically most dominant channel. However, for highly precessing binaries or binaries with moderately large mass ratios, significant power is also carried by higher-order modes. We investigate how the inclusion of higher modes in the templates increases the prospects for detecting gravitational waves. Specifically, we use numerical relativity waveforms from the late inspiral and coalescence of binary black holes to identify mode hierarchies that cover the sky of binary orientations. We show that the ordering in these hierarchies depends on the characteristics of the binary system and the mode strengths. Our study demonstrates that detecting moderately high precessing or unequal mass binaries requires the inclusion of higher modes in the templat...

  15. A systematic search for close supermassive black hole binaries in the Catalina Real-time Transient Survey

    Science.gov (United States)

    Graham, Matthew J.; Djorgovski, S. G.; Stern, Daniel; Drake, Andrew J.; Mahabal, Ashish A.; Donalek, Ciro; Glikman, Eilat; Larson, Steve; Christensen, Eric

    2015-10-01

    Hierarchical assembly models predict a population of supermassive black hole (SMBH) binaries. These are not resolvable by direct imaging but may be detectable via periodic variability (or nanohertz frequency gravitational waves). Following our detection of a 5.2-year periodic signal in the quasar PG 1302-102, we present a novel analysis of the optical variability of 243 500 known spectroscopically confirmed quasars using data from the Catalina Real-time Transient Survey (CRTS) to look for close (warped accretion discs or periodic accretion associated with a close SMBH binary system. We also consider how other SMBH binary candidates in the literature appear in CRTS data and show that none of these are equivalent to the identified objects. Finally, the distribution of objects found is consistent with that expected from a gravitational-wave-driven population. This implies that circumbinary gas is present at small orbital radii and is being perturbed by the black holes. None of the sources is expected to merge within at least the next century. This study opens a new unique window to study a population of close SMBH binaries that must exist according to our current understanding of galaxy and SMBH evolution.

  16. Eclipsing binary stars in the Large Magellanic Cloud. Results from the EROS-2, OGLE and VMC surveys

    CERN Document Server

    Muraveva, T; Maceroni, C; Evans, C J; Moretti, M I; Cioni, M -R L; Marquette, J B; Ripepi, V; de Grijs, R; Groenewegen, M A T; Piatti, A E; van Loon, J Th

    2014-01-01

    We present a catalogue of 1768 eclipsing binary stars (EBs) detected in the Large Magellanic Cloud (LMC) by the second generation of the EROS survey (hereinafter EROS-2); 493 of them are new discoveries located in outer regions (out of the central bar) of the LMC. These sources were originally included in a list of candidate classical Cepheids (CCs) extracted from the EROS-2 catalogue on the basis of the period (0.89 $binaries. They have blue colours ($B_{EROS} - R_{EROS} < $ 0.2 mag) hence we classed them as hot eclipsing binaries (HEBs) containing hot massive components: main sequence (MS) stars or blue giants. We present $K_{\\rm s}$-band light curves for 999 binaries from our sample that have a counterpart in the VISTA near-infrared ESO public survey of the Magellanic Clouds system (VMC). We provide spectral classificati...

  17. Exploring eclipsing binaries, triples and higher-order multiple star systems with the SuperWASP archive

    CERN Document Server

    Lohr, M E

    2015-01-01

    The Super Wide Angle Search for Planets (SuperWASP) is a whole-sky high-cadence optical survey which has searched for exoplanetary transit signatures since 2004. Its archive contains long-term light curves for ~30 million 8-15 V magnitude stars, making it a valuable serendipitous resource for variable star research. We have concentrated on the evidence it provides for eclipsing binaries, in particular those exhibiting orbital period variations, and have developed custom tools to measure periods precisely and detect period changes reliably. Amongst our results are: a collection of 143 candidate contact or semi-detached eclipsing binaries near the short-period limit in the main sequence binary period distribution; a probable hierarchical triple exhibiting dramatic sinusoidal period variations; a new doubly-eclipsing quintuple system; and new evidence for period change or stability in 12 post-common-envelope eclipsing binaries, which may support the existence of circumbinary planets in such systems. A large-scal...

  18. [Searching for WDMS Candidates In SDSS-DR10 With Automatic Method].

    Science.gov (United States)

    Jiang, Bin; Wang, Cheng-you; Wang, Wen-yu; Wang, Wei

    2015-05-01

    The Sloan Digital Sky Survey (SDSS) has released the latest data (DR10) which covers the first APOGEE spectra. The massive spectra can be used for large sample research inscluding the structure and evolution of the Galaxy and multi-wave-band identi cation. In addition, the spectra are also ideal for searching for rare and special objects like white dwarf main-sequence star (WDMS). WDMS consist of a white dwarf primary and a low-mass main-sequence (MS) companion which has positive significance to the study of evolution and parameter of close binaries. WDMS is generally discovered by repeated imaging of the same area of sky, measuring light curves for objects or through photometric selection with follow-up observations. These methods require significant manual processing time with low accuracy and the real-time processing requirements can not be satisfied. In this paper, an automatic and efficient method for searching for WDMS candidates is presented. The method Genetic Algorithm (GA) is applied in the newly released SDSS-DR10 spectra. A total number of 4 140 WDMS candidates are selected by the method and 24 of them are new discoveries which prove that our approach of finding special celestial bodies in massive spectra data is feasible. In addition, this method is also applicable to mining other special celestial objects in sky survey telescope data. We report the identfication of 24 new WDMS with spectra. A compendium of positions, mjd, plate and fiberid of these new discoveries is presented which enrich the spectral library and will be useful to the research of binary evolution models. PMID:26415473

  19. High Resolution Imaging of Very Low Mass Spectral Binaries: Three Resolved Systems and Detection of Orbital Motion in an L/T Transition Binary

    Science.gov (United States)

    Bardalez Gagliuffi, Daniella C.; Gelino, Christopher R.; Burgasser, Adam J.

    2015-11-01

    We present high resolution Laser Guide Star Adaptive Optics imaging of 43 late-M, L and T dwarf systems with Keck/NIRC2. These include 17 spectral binary candidates, systems whose spectra suggest the presence of a T dwarf secondary. We resolve three systems: 2MASS J1341-3052, SDSS J1511+0607 and SDSS J2052-1609 the first two are resolved for the first time. All three have projected separations Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  20. An object that defies stereotypes. X-ray observations of SBS 1150+599A -- the binary nucleus of PN G135.9+55.9

    CERN Document Server

    Tovmassian, G; Napiwotzki, R; Yungelson, L; Stasińska, G; Peña, M; Richer, M

    2007-01-01

    We present X-ray observations of the close binary nucleus of the planetary nebula PN G135.9+55.9 obtained with the XMM satellite. The nebula is the most oxygen-poor PN known to date and is located in the Galactic halo. It is known to harbor a close binary nucleus of which only one component can be observed in optical-UV range. New X-ray observations show that the invisible component is a very hot compact star. This finding allows us to reconstruct the immediate past of the object and predict its future. The parameters of the binary components we determine strongly suggest that the precursor was a symbiotic supersoft X-ray source that finished its life by Roche lobe overflow. PN G135.9+55.9 is an excelent candidate for a future type Ia supernova.