WorldWideScience

Sample records for high-precision light curves

  1. Effect of stellar activity on the high precision transit light curve

    Oshagh, M.

    2015-01-01

    Full Text Available Stellar activity features such as spots and plages can create difficulties in determining planetary parameters through spectroscopic and photometric observations. The overlap of a transiting planet and a stellar spot, for instance, can produce anomalies in the transit light curve that may lead to inaccurate estimation of the transit duration, depth, and timing. Such inaccuracies can affect the precise derivation of the planet’s radius. In this talk we will present the results of a quantitative study on the effects of stellar spots on high precision transit light curves. We show that spot anomalies can lead to the estimate of a planet radius that is 4% smaller than the real value. The effects on the transit duration can also be of the order of 4%, longer or shorter. Depending on the size and distribution of spots, anomalies can also produce transit timing variations with significant amplitudes. For instance, TTVs with signal amplitudes of 200 seconds can be produced by spots as large as the largest sunspot. Finally, we examine the impact of active regions on the transit depth measurements in different wavelengths, in order to probe the impact of this effect on transmission spectroscopy measurements. We show that significant (up to 10% underestimation/overestimation of the planet-to-star radius ratio can be measured, especially in the short wavelength regime.

  2. High-precision 2MASS JHK{sub s} light curves and other data for RR Lyrae star SDSS J015450 + 001501: Strong constraints for nonlinear pulsation models

    Szabó, Róbert; Ivezić, Željko; Kiss, László L.; Kolláth, Zoltán [Konkoly Observatory, MTA CSFK, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Jones, Lynne; Becker, Andrew C.; Davenport, James R. A. [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195-1580 (United States); Sesar, Branimir [Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125 (United States); Cutri, Roc M., E-mail: rszabo@konkoly.hu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-01-01

    We present and discuss an extensive data set for the non-Blazhko ab-type RR Lyrae star SDSS J015450+001501, including optical Sloan Digital Sky Survey ugriz light curves and spectroscopic data, LINEAR and Catalina Sky Survey unfiltered optical light curves, and infrared Two Micron All Sky Survey (2MASS) JHK{sub s} and Wide-field Infrared Survey Explorer W1 and W2 light curves. Most notable is that light curves obtained by 2MASS include close to 9000 photometric measures collected over 3.3 yr and provide an exceedingly precise view of near-infrared variability. These data demonstrate that static atmosphere models are insufficient to explain multiband photometric light-curve behavior and present strong constraints for nonlinear pulsation models for RR Lyrae stars. It is a challenge to modelers to produce theoretical light curves that can explain data presented here, which we make publicly available.

  3. Simulating Supernova Light Curves

    Even, Wesley Paul; Dolence, Joshua C.

    2016-01-01

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth's atmosphere.

  4. Simulating Supernova Light Curves

    Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  5. LCC: Light Curves Classifier

    Vo, Martin

    2017-08-01

    Light Curves Classifier uses data mining and machine learning to obtain and classify desired objects. This task can be accomplished by attributes of light curves or any time series, including shapes, histograms, or variograms, or by other available information about the inspected objects, such as color indices, temperatures, and abundances. After specifying features which describe the objects to be searched, the software trains on a given training sample, and can then be used for unsupervised clustering for visualizing the natural separation of the sample. The package can be also used for automatic tuning parameters of used methods (for example, number of hidden neurons or binning ratio). Trained classifiers can be used for filtering outputs from astronomical databases or data stored locally. The Light Curve Classifier can also be used for simple downloading of light curves and all available information of queried stars. It natively can connect to OgleII, OgleIII, ASAS, CoRoT, Kepler, Catalina and MACHO, and new connectors or descriptors can be implemented. In addition to direct usage of the package and command line UI, the program can be used through a web interface. Users can create jobs for ”training” methods on given objects, querying databases and filtering outputs by trained filters. Preimplemented descriptors, classifier and connectors can be picked by simple clicks and their parameters can be tuned by giving ranges of these values. All combinations are then calculated and the best one is used for creating the filter. Natural separation of the data can be visualized by unsupervised clustering.

  6. High Precision Stokes Polarimetry for Scattering Light using Wide Dynamic Range Intensity Detector

    Shibata Shuhei

    2015-01-01

    Full Text Available This paper proposes a Stokes polarimetry for scattering light from a sample surface. To achieve a high accuracy measurement two approaches of an intensity detector and analysis algorism of a Stokes parameter were proposed. The dynamic range of this detector can achieve up to 1010 by combination of change of neutral-density (ND filters having different density and photon counting units. Stokes parameters can be measured by dual rotating of a retarder and an analyzer. The algorism of dual rotating polarimeter can be calibrated small linear diattenuation and linear retardance error of the retarder. This system can measured Stokes parameters from −20° to 70° of its scattering angle. It is possible to measure Stokes parameters of scattering of dust and scratch of optical device with high precision. This paper shows accuracy of this system, checking the polarization change of scattering angle and influence of beam size.

  7. Accurate and emergent applications for high precision light small aerial remote sensing system

    Pei, Liu; Yingcheng, Li; Yanli, Xue; Xiaofeng, Sun; Qingwu, Hu

    2014-01-01

    In this paper, we focus on the successful applications of accurate and emergent surveying and mapping for high precision light small aerial remote sensing system. First, the remote sensing system structure and three integrated operation modes will be introduced. It can be combined to three operation modes depending on the application requirements. Second, we describe the preliminary results of a precision validation method for POS direct orientation in 1:500 mapping. Third, it presents two fast response mapping products- regional continuous three-dimensional model and digital surface model, taking the efficiency and accuracy evaluation of the two products as an important point. The precision of both products meets the 1:2 000 topographic map accuracy specifications in Pingdingshan area. In the end, conclusions and future work are summarized

  8. Accurate and emergent applications for high precision light small aerial remote sensing system

    Pei, Liu; Yingcheng, Li; Yanli, Xue; Qingwu, Hu; Xiaofeng, Sun

    2014-03-01

    In this paper, we focus on the successful applications of accurate and emergent surveying and mapping for high precision light small aerial remote sensing system. First, the remote sensing system structure and three integrated operation modes will be introduced. It can be combined to three operation modes depending on the application requirements. Second, we describe the preliminary results of a precision validation method for POS direct orientation in 1:500 mapping. Third, it presents two fast response mapping products- regional continuous three-dimensional model and digital surface model, taking the efficiency and accuracy evaluation of the two products as an important point. The precision of both products meets the 1:2 000 topographic map accuracy specifications in Pingdingshan area. In the end, conclusions and future work are summarized.

  9. High-precision predictions for the light CP-even Higgs boson mass of the MSSM

    Hahn, T.; Hollik, W. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Rzehak, H. [Freiburg Univ. (Germany). Physikalisches Inst.; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2014-03-15

    For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realised in the Standard Model (SM) and its most commonly studied extension, the Minimal Supersymmetric SM (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, M{sub h}, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for M{sub h} in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FeynHiggs.

  10. High-precision MoSi multilayer coatings for radial and 2D designs on curved optics

    Kriese, Michael D.; Li, Yang; Platonov, Yuriy Y.

    2017-10-01

    The development of industrial infrastructure for EUV lithography requires a wide array of optics beyond the mask and the scanner optics, which include optics for critical instruments such as exposure testing and actinic inspection. This paper will detail recent results in the production of a variety of high-precision multilayer coatings achieved to support this development. It is critical that the optical designs factor in the capabilities of the achievable multilayer gradients and the associated achievable precision, including impact to surface distortion from the added figure error of the multilayer coating, which adds additional requirements of a specific shape to the period distribution. For example, two different coatings may achieve a ±0.2% variation in multilayer period, but have considerably different added figure error. Part I of the paper will focus on radially-symmetric spherical and aspherical optics. Typical azimuthal uniformity (variation at a fixed radius) achieved is less than ±0.005nm total variation, including measurement precision, on concave optics up to 200mm diameter. For highly curved convex optics (radius of curvature less than 50mm), precision is more challenging and the total variation increases to ±0.01nm total variation for optics 10-30mm in diameter. Total added figure error achieved has been as low as 0.05nm. Part II of the paper will focus on multilayer designs graded in two directions, rather than radially, in order to accommodate the increased complexity of elliptical, toroidal and hyperbolic surfaces. In most cases, the symmetry of the required multilayer gradient does not match the symmetry of the optical surface, and this interaction must be countered via the process design. Achieving such results requires additional flexibility in the design of the deposition equipment, and will be discussed with several examples in the paper, such as the use of variable velocity of an inline substrate carrier in conjunction with a shaped

  11. High-precision soft x-ray polarimeter at Diamond Light Source.

    Wang, H; Dhesi, S S; Maccherozzi, F; Cavill, S; Shepherd, E; Yuan, F; Deshmukh, R; Scott, S; van der Laan, G; Sawhney, K J S

    2011-12-01

    The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 μrad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B(4)C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed.

  12. An automatic high precision registration method between large area aerial images and aerial light detection and ranging data

    Du, Q.; Xie, D.; Sun, Y.

    2015-06-01

    The integration of digital aerial photogrammetry and Light Detetion And Ranging (LiDAR) is an inevitable trend in Surveying and Mapping field. We calculate the external orientation elements of images which identical with LiDAR coordinate to realize automatic high precision registration between aerial images and LiDAR data. There are two ways to calculate orientation elements. One is single image spatial resection using image matching 3D points that registered to LiDAR. The other one is Position and Orientation System (POS) data supported aerotriangulation. The high precision registration points are selected as Ground Control Points (GCPs) instead of measuring GCPs manually during aerotriangulation. The registration experiments indicate that the method which registering aerial images and LiDAR points has a great advantage in higher automation and precision compare with manual registration.

  13. Three-dimensional high-precision indoor positioning strategy using Tabu search based on visible light communication

    Peng, Qi; Guan, Weipeng; Wu, Yuxiang; Cai, Ye; Xie, Canyu; Wang, Pengfei

    2018-01-01

    This paper proposes a three-dimensional (3-D) high-precision indoor positioning strategy using Tabu search based on visible light communication. Tabu search is a powerful global optimization algorithm, and the 3-D indoor positioning can be transformed into an optimal solution problem. Therefore, in the 3-D indoor positioning, the optimal receiver coordinate can be obtained by the Tabu search algorithm. For all we know, this is the first time the Tabu search algorithm is applied to visible light positioning. Each light-emitting diode (LED) in the system broadcasts a unique identity (ID) and transmits the ID information. When the receiver detects optical signals with ID information from different LEDs, using the global optimization of the Tabu search algorithm, the 3-D high-precision indoor positioning can be realized when the fitness value meets certain conditions. Simulation results show that the average positioning error is 0.79 cm, and the maximum error is 5.88 cm. The extended experiment of trajectory tracking also shows that 95.05% positioning errors are below 1.428 cm. It can be concluded from the data that the 3-D indoor positioning based on the Tabu search algorithm achieves the requirements of centimeter level indoor positioning. The algorithm used in indoor positioning is very effective and practical and is superior to other existing methods for visible light indoor positioning.

  14. Automated Blazar Light Curves Using Machine Learning

    Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-27

    This presentation describes a problem and methodology pertaining to automated blazar light curves. Namely, optical variability patterns for blazars require the construction of light curves and in order to generate the light curves, data must be filtered before processing to ensure quality.

  15. High-precision predictions for the light CP-even Higgs boson mass of the minimal supersymmetric standard model.

    Hahn, T; Heinemeyer, S; Hollik, W; Rzehak, H; Weiglein, G

    2014-04-11

    For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realized in the standard model (SM) and its most commonly studied extension, the minimal supersymmetric standard model (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, Mh, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for Mh in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FEYNHIGGS.

  16. Indoor high precision three-dimensional positioning system based on visible light communication using modified genetic algorithm

    Chen, Hao; Guan, Weipeng; Li, Simin; Wu, Yuxiang

    2018-04-01

    To improve the precision of indoor positioning and actualize three-dimensional positioning, a reversed indoor positioning system based on visible light communication (VLC) using genetic algorithm (GA) is proposed. In order to solve the problem of interference between signal sources, CDMA modulation is used. Each light-emitting diode (LED) in the system broadcasts a unique identity (ID) code using CDMA modulation. Receiver receives mixed signal from every LED reference point, by the orthogonality of spreading code in CDMA modulation, ID information and intensity attenuation information from every LED can be obtained. According to positioning principle of received signal strength (RSS), the coordinate of the receiver can be determined. Due to system noise and imperfection of device utilized in the system, distance between receiver and transmitters will deviate from the real value resulting in positioning error. By introducing error correction factors to global parallel search of genetic algorithm, coordinates of the receiver in three-dimensional space can be determined precisely. Both simulation results and experimental results show that in practical application scenarios, the proposed positioning system can realize high precision positioning service.

  17. High Precision Motion Control System for the Two-Stage Light Gas Gun at the Dynamic Compression Sector

    Zdanowicz, E.; Guarino, V.; Konrad, C.; Williams, B.; Capatina, D.; D'Amico, K.; Arganbright, N.; Zimmerman, K.; Turneaure, S.; Gupta, Y. M.

    2017-06-01

    The Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS), located at Argonne National Laboratory (ANL), has a diverse set of dynamic compression drivers to obtain time resolved x-ray data in single event, dynamic compression experiments. Because the APS x-ray beam direction is fixed, each driver at DCS must have the capability to move through a large range of linear and angular motions with high precision to accommodate a wide variety of scientific needs. Particularly challenging was the design and implementation of the motion control system for the two-stage light gas gun, which rests on a 26' long structure and weighs over 2 tons. The target must be precisely positioned in the x-ray beam while remaining perpendicular to the gun barrel axis to ensure one-dimensional loading of samples. To accommodate these requirements, the entire structure can pivot through 60° of angular motion and move 10's of inches along four independent linear directions with 0.01° and 10 μm resolution, respectively. This presentation will provide details of how this system was constructed, how it is controlled, and provide examples of the wide range of x-ray/sample geometries that can be accommodated. Work supported by DOE/NNSA.

  18. Deep-learnt classification of light curves

    Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru

    2017-01-01

    Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach is to d...

  19. Light extraction block with curved surface

    Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.

    2016-03-22

    Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.

  20. Reflected Light Curves of Extrasolar Planets

    Green, D.; Matthews, J.; Kuschnig, R.; Seager, S.

    The planned launches of ultra-precise photometric satellites such as MOST, COROT and MONS should provide the first opportunity to study the reflected light curves from extrasolar planets. To predict the capabilities of these missions, we have constructed a series of models of such light curves, improving upon the Monte Carlo simulations by Seager et al. (2000). These models include more realistic features such limb darkening of the star and broad band photometry. For specific models, the resulting planet light curves exhibit unique behavior with the variation of radius, inclination and presence or absence of clouds.

  1. Classification of ASKAP Vast Radio Light Curves

    Rebbapragada, Umaa; Lo, Kitty; Wagstaff, Kiri L.; Reed, Colorado; Murphy, Tara; Thompson, David R.

    2012-01-01

    The VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light curve characterization and classification algorithms that are best suited for archival VAST light curve classification. We perform our experiments on light curve simulations of eight source types and achieve best case performance of approximately 90% accuracy. We note that classification performance is most influenced by light curve characterization rather than classifier algorithm.

  2. Light Curve Analysis of SAO23229

    Ho-Il Kim

    1993-06-01

    Full Text Available We have made UBV light curves of a newly discovered eclipsing binary, SAO23229 at Sobaeksan Astronomy Observatory. We determined a minimum light time of HJD2448636.1170+/-0.0005 that is 3 minutes later than predicted time, and founda peculiar light variation at phase 0.75 that may not be secondary eclipse. Orbital period of SAO23229 would be 4.2 days rather than 2.1 days. Our analysis of the light curves shows that SAO23229 has a detached configuration consisting of two almost identical F type main sequence stars.

  3. Light propagation in the gravitational field of N arbitrarily moving bodies in the 1.5PN approximation for high-precision astrometry

    Zschocke, Sven

    2016-05-01

    High-precision astrometry on sub-micro-arcsecond level in angular resolution requires accurate determination of the trajectory of a light-signal from the celestial light source through the gravitational field of the Solar System toward the observer. In this investigation the light trajectory in the gravitational field of N moving bodies is determined in the 1.5 post-Newtonian approximation. In the approach presented two specific issues of particular importance are accounted for: (1) According to the recommendations of International Astronomical Union, the metric of the Solar System is expressed in terms of intrinsic mass-multipoles and intrinsic spin-multipoles of the massive bodies, allowing for arbitrary shape, inner structure and rotational motion of the massive bodies of the Solar System. (2) The Solar System bodies move along arbitrary world lines which can later be specified by Solar System ephemeris. The presented analytical solution for light trajectory is a primary requirement for extremely high-precision astrometry on sub-micro-arcsecond level of accuracy and associated massive computations in astrometric data reduction. An estimation of the numerical magnitude for time delay and light deflection of the leading multipoles is given.

  4. Multiwavelength light curve parameters of Cepheid variables

    Bhardwaj Anupam

    2017-01-01

    Full Text Available We present a comparative analysis of theoretical and observed light curves of Cepheid variables using Fourier decomposition. The theoretical light curves at multiple wavelengths are generated using stellar pulsation models for chemical compositions representative of Cepheids in the Galaxy and Magellanic Clouds. The observed light curves at optical (VI, near-infrared (JHKs and mid-infrared (3.6 & 4.5-μm bands are compiled from the literature. We discuss the variation of light curve parameters as a function of period, wavelength and metallicity. Theoretical and observed Fourier amplitude parameters decrease with increase in wavelength while the phase parameters increase with wavelength. We find that theoretical amplitude parameters obtained using canonical mass-luminosity levels exhibit a greater offset with respect to observations when compared to non-canonical relations. We also discuss the impact of variation in convective efficiency on the light curve structure of Cepheid variables. The increase in mixing length parameter results in a zero-point offset in bolometric mean magnitudes and reduces the systematic large difference in theoretical amplitudes with respect to observations.

  5. a new approach of Analysing GRB light curves

    Varga, B.; Horvath, I.

    2005-01-01

    We estimated the T xx quantiles of the cumulative GRB light curves using our recalculated background. The basic information of the light curves was extracted by multivariate statistical methods. The possible classes of the light curves are also briefly discussed

  6. Deep-learnt classification of light curves

    Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru

    2017-01-01

    is to derive statistical features from the time series and to use machine learning methods, generally supervised, to separate objects into a few of the standard classes. In this work, we transform the time series to two-dimensional light curve representations in order to classify them using modern deep......Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach...... learning techniques. In particular, we show that convolutional neural networks based classifiers work well for broad characterization and classification. We use labeled datasets of periodic variables from CRTS survey and show how this opens doors for a quick classification of diverse classes with several...

  7. Development of ultra-light pixelated systems based on CMOS sensors for future high precision vertex detectors

    Winter, Marc [Institut Pluridisciplinaire Hubert Curien - IPHC, 23 rue du loess - BP28, 67037 Strasbourg cedex 2 (France)

    2010-07-01

    CMOS pixel sensors have demonstrated attractive performances in terms of spatial resolution and material budget. The recent emergence of high resistivity substrates in mass production CMOS processes has originated particularly high signal-to-noise ratios and improved the non-ionising radiation tolerance to fluences close to 10{sup 14} Neq/cm{sup 2}. These achievements, obtained with MIMOSA sensors developed at IPHC (Strasbourg) and IRFU (Saclay) will be overviewed and put in perspective of the numerous applications of the sensors. These include collider experiments at RHIC, LHC, ILC and CLIC. The development of ultra-light ladders composed of these sensors and featuring 0.1% to 0.3% of radiation length, will be summarised. The contribution to the conference will also address the evolution of these pixelated systems, including on-going R on multi-tier sensors exploiting vertical integration technologies. (author)

  8. High-precision approach to localization scheme of visible light communication based on artificial neural networks and modified genetic algorithms

    Guan, Weipeng; Wu, Yuxiang; Xie, Canyu; Chen, Hao; Cai, Ye; Chen, Yingcong

    2017-10-01

    An indoor positioning algorithm based on visible light communication (VLC) is presented. This algorithm is used to calculate a three-dimensional (3-D) coordinate of an indoor optical wireless environment, which includes sufficient orders of multipath reflections from reflecting surfaces of the room. Leveraging the global optimization ability of the genetic algorithm (GA), an innovative framework for 3-D position estimation based on a modified genetic algorithm is proposed. Unlike other techniques using VLC for positioning, the proposed system can achieve indoor 3-D localization without making assumptions about the height or acquiring the orientation angle of the mobile terminal. Simulation results show that an average localization error of less than 1.02 cm can be achieved. In addition, in most VLC-positioning systems, the effect of reflection is always neglected and its performance is limited by reflection, which makes the results not so accurate for a real scenario and the positioning errors at the corners are relatively larger than other places. So, we take the first-order reflection into consideration and use artificial neural network to match the model of a nonlinear channel. The studies show that under the nonlinear matching of direct and reflected channels the average positioning errors of four corners decrease from 11.94 to 0.95 cm. The employed algorithm is emerged as an effective and practical method for indoor localization and outperform other existing indoor wireless localization approaches.

  9. Aspherical Supernovae: Effects on Early Light Curves

    Afsariardchi, Niloufar; Matzner, Christopher D.

    2018-04-01

    Early light from core-collapse supernovae, now detectable in high-cadence surveys, holds clues to a star and its environment just before it explodes. However, effects that alter the early light have not been fully explored. We highlight the possibility of nonradial flows at the time of shock breakout. These develop in sufficiently nonspherical explosions if the progenitor is not too diffuse. When they do develop, nonradial flows limit ejecta speeds and cause ejecta–ejecta collisions. We explore these phenomena and their observational implications using global, axisymmetric, nonrelativistic FLASH simulations of simplified polytropic progenitors, which we scale to representative stars. We develop a method to track photon production within the ejecta, enabling us to estimate band-dependent light curves from adiabatic simulations. Immediate breakout emission becomes hidden as an oblique flow develops. Nonspherical effects lead the shock-heated ejecta to release a more constant luminosity at a higher, evolving color temperature at early times, effectively mixing breakout light with the early light curve. Collisions between nonradial ejecta thermalize a small fraction of the explosion energy; we will address emission from these collisions in a subsequent paper.

  10. SPOTTED STAR LIGHT CURVES WITH ENHANCED PRECISION

    Wilson, R. E.

    2012-01-01

    The nearly continuous timewise coverage of recent photometric surveys is free of the large gaps that compromise attempts to follow starspot growth and decay as well as motions, thereby giving incentive to improve computational precision for modeled spots. Due to the wide variety of star systems in the surveys, such improvement should apply to light/velocity curve models that accurately include all the main phenomena of close binaries and rotating single stars. The vector fractional area (VFA) algorithm that is introduced here represents surface elements by small sets of position vectors so as to allow accurate computation of circle-triangle overlap by spherical geometry. When computed by VFA, spots introduce essentially no noticeable scatter in light curves at the level of one part in 10,000. VFA has been put into the Wilson-Devinney light/velocity curve program and all logic and mathematics are given so as to facilitate entry into other such programs. Advantages of precise spot computation include improved statistics of spot motions and aging, reduced computation time (intrinsic precision relaxes needs for grid fineness), noise-free illustration of spot effects in figures, and help in guarding against false positives in exoplanet searches, where spots could approximately mimic transiting planets in unusual circumstances. A simple spot growth and decay template quantifies time profiles, and specifics of its utilization in differential corrections solutions are given. Computational strategies are discussed, the overall process is tested in simulations via solutions of synthetic light curve data, and essential simulation results are described. An efficient time smearing facility by Gaussian quadrature can deal with Kepler mission data that are in 30 minute time bins.

  11. Light Curve Variations of AR Lacertae

    Il-Seong Nha

    1991-12-01

    Full Text Available Sixteen unitary Light curves of AR Lac in B and V are made at Yonsei University Observatory in the period of 1980-1988. Some overview findings of light variations are made. (1 The light variations outside eclipse follow none of the wave migration patterns reported by previous investigators. (2 Complicated shapes outside eclipse are apparently much reduced in the light curves of 1983-1984. This suggests that, in the future, AR Lac has a chance to attain a normal state with mo complicated interactions. (3 The depths of the primary and the secondary mid-eclipses are changing year-to-year. (4 The K0 star, the larger component, has brightened by 0.m14 V, while the G2 star has shown a fluctuation of about 0.m05 in V. (5 The B-V values at primary mid-eclipse have no correlation with the depth variations. (6 Independently of the increase of maximum brightness, the B-V colors in the non-eclipsed phases changed slightly over the years.

  12. Photoelectic BV Light Curves of Algol and the Interpretations of the Light Curves

    Ho-Il Kim

    1985-06-01

    Full Text Available Standardized B and V photoelectric light curves of Algol are made with the observations obtained during 1982-84 with the 40-cm and the 61-cm reflectors of Yonsei University Observatory. These light curves show asymmetry between ascending and descending shoulders. The ascending shoulder is 0.02 mag brighter than descending shoulder in V light curve and 0.03 mag in B light curve. These asymmetric light curves are interpreted as the result of inhomogeneous energy distribution on the surface of one star of the eclipsing pair rather than the result of gaseous stream flowing from KOIV to B8V star. The 180-year periodicity, so called great inequality, are most likely the result proposed by Kim et al. (1983 that the abrupt and discrete mass losses of cooler component may be the cause of this orbital change. The amount of mass loss deduced from these discrete period changes turned out to be of the order of 10^(-6 - 10^(-5 Msolar.

  13. SUPERNOVA LIGHT CURVES POWERED BY FALLBACK ACCRETION

    Dexter, Jason; Kasen, Daniel, E-mail: jdexter@berkeley.edu [Departments of Physics and Astronomy, University of California, Berkeley, CA 94720 (United States)

    2013-07-20

    Some fraction of the material ejected in a core collapse supernova explosion may remain bound to the compact remnant, and eventually turn around and fall back. We show that the late time ({approx}>days) power potentially associated with the accretion of this 'fallback' material could significantly affect the optical light curve, in some cases producing super-luminous or otherwise peculiar supernovae. We use spherically symmetric hydrodynamical models to estimate the accretion rate at late times for a range of progenitor masses and radii and explosion energies. The accretion rate onto the proto-neutron star or black hole decreases as M-dot {proportional_to}t{sup -5/3} at late times, but its normalization can be significantly enhanced at low explosion energies, in very massive stars, or if a strong reverse shock wave forms at the helium/hydrogen interface in the progenitor. If the resulting super-Eddington accretion drives an outflow which thermalizes in the outgoing ejecta, the supernova debris will be re-energized at a time when photons can diffuse out efficiently. The resulting light curves are different and more diverse than previous fallback supernova models which ignored the input of accretion power and produced short-lived, dim transients. The possible outcomes when fallback accretion power is significant include super-luminous ({approx}> 10{sup 44} erg s{sup -1}) Type II events of both short and long durations, as well as luminous Type I events from compact stars that may have experienced significant mass loss. Accretion power may unbind the remaining infalling material, causing a sudden decrease in the brightness of some long duration Type II events. This scenario may be relevant for explaining some of the recently discovered classes of peculiar and rare supernovae.

  14. Interpretation of photometric observations of R Coronae Borealis. Light curves

    Pugach, A.F.

    1990-01-01

    The calculations confirm the 'reptive hypothesis' of light variations of R CrB. The central point of the hypothesis is an assertion of infinite expansion of an elementary dust cloud. The calculations for different masses of the dust cloud provide a set of elementary light curves. Superposition of the curves yields a complex light curve. The comparison with the observed minima of 1972 has been performed

  15. Physics of Eclipsing Binaries: Modelling in the new era of ultra-high precision photometry

    Pavlovski, K.; Bloemen, S.; Degroote, P.; Conroy, K.; Hambleton, Kelly; Giammarco, J.M.; Pablo, H.; Prša, A.; Tkachenko, A.; Torres, G.

    2013-01-01

    Recent ultra-high precision observations of eclipsing binaries, especially data acquired by the Kepler satellite, have made accurate light curve modelling increasingly challenging but also more rewarding. In this contribution, we discuss low-amplitude signals in light curves that can now be used to derive physical information about eclipsing binaries but that were unaccessible before the Kepler era. A notable example is the detection of Doppler beaming, which leads to an increase in flux when...

  16. Rectification of light refraction in curved waveguide arrays.

    Longhi, Stefano

    2009-02-15

    An "optical ratchet" for discretized light in photonic lattices, which enables observing rectification of light refraction at any input beam conditions, is theoretically presented, and a possible experimental implementation based on periodically curved zigzag waveguide arrays is proposed.

  17. Rectification of light refraction in curved waveguide arrays

    Longhi, S.

    2010-01-01

    An 'optical ratchet' for discretized light in photonic lattices, which enables to observe rectification of light refraction at any input beam conditions, is theoretically presented, and a possible experimental implementation based on periodically-curved zigzag waveguide arrays is proposed.

  18. An Alternate Light Curve Solution of AR Lacertae

    Hong Suh Park

    1984-09-01

    Full Text Available Photoelectric UBV light curves of AR Lacertae made in one season during 1981-82 are presented. Although the shape of the light curves in the outside eclipses show a strong distortion, the scatter of observations as well as phase coverage are better than those previously available. Fourier coefficients are derived from the V-light curve and observed curve successfully rectified to the Russell model. Light curve solutions are computed and the geometrical and physical parameters of AR Lac are derived as as = 0.812, ag = 0.341, j = 86°3, Ls = 0.372, Lg = 0.628, k = 0.53, Xs = 0.85, Xg = 0.4.

  19. Explosions and light curves of supernovae

    Gaffet, B.

    1975-01-01

    The models developed to explain supernovae explosions are reviewed. The first one is thermonuclear explosion (simple or preceded by an implosion phase); the neutrino emission which results of such an explosion can have an important dynamical effect, according as the star is opaque or transparent to them; another theory involves the radiation pressure of the pulsar which is formed in the center of the star. The origin of the supernovae brightness is also uncertain: the initial heat due to the explosion does not seem to be sufficient; the brightness can result from the diffusion of the heat through the ejected matter or can be transported more rapidly by a shock wave. A model in which the heat is produced by the pulsar seems compatible with most observations (shapes of the brightness curves and the continuum spectra, expansion velocities, temperature and luminosity at the peak, total kinetic energy) [fr

  20. Light Curve Solution of the Contact Binary AW UMa

    J. H. Jeong

    1997-12-01

    Full Text Available A total of 1088 observations (272 in B,272 in V, 272 in R, and 272 in I were made from January to February in 1995 at Chungbuk National University observatory(CbNUO. We constructed BVRI light curves with our data. The photometric solution of these light curves was obtained by means of the Wilson-Devinney method. Our result was compared with those by previous investigators.

  1. EVEREST: Pixel Level Decorrelation of K2 Light Curves

    Luger, Rodrigo; Agol, Eric; Kruse, Ethan; Barnes, Rory; Becker, Andrew; Foreman-Mackey, Daniel; Deming, Drake

    2016-10-01

    We present EPIC Variability Extraction and Removal for Exoplanet Science Targets (EVEREST), an open-source pipeline for removing instrumental noise from K2 light curves. EVEREST employs a variant of pixel level decorrelation to remove systematics introduced by the spacecraft’s pointing error and a Gaussian process to capture astrophysical variability. We apply EVEREST to all K2 targets in campaigns 0-7, yielding light curves with precision comparable to that of the original Kepler mission for stars brighter than {K}p≈ 13, and within a factor of two of the Kepler precision for fainter targets. We perform cross-validation and transit injection and recovery tests to validate the pipeline, and compare our light curves to the other de-trended light curves available for download at the MAST High Level Science Products archive. We find that EVEREST achieves the highest average precision of any of these pipelines for unsaturated K2 stars. The improved precision of these light curves will aid in exoplanet detection and characterization, investigations of stellar variability, asteroseismology, and other photometric studies. The EVEREST pipeline can also easily be applied to future surveys, such as the TESS mission, to correct for instrumental systematics and enable the detection of low signal-to-noise transiting exoplanets. The EVEREST light curves and the source code used to generate them are freely available online.

  2. Optical and IR light curves of VV Puppis

    Szkody, P.; Bailey, J.A.; Hough, J.H.

    1983-01-01

    We present optical (0.36 to 0.6 μm) light curves with time resolutions of seconds and infrared (IR) (1.25 to 2.2 μm) light curves with time resolutions of minutes for VV Puppis during a high state. The optical light curves show a single hump with largest amplitude in the V filter, while the IR light curves show a double hump sinusoidal variation. Flickering is evident in both the optical and IR light curves, with the largest amplitude in optical B light. Through subtraction of the low state fluxes from our high state values, we obtain a flux distribution of the accretion column which peaks at 0.55 μm and becomes #betta# 2 in the IR, consistent with current cyclotron models. Comparison of the observed IR variations throughout the orbit with the expected variations due to an M4 star heated by an accretion column at an inclination of 66 0 suggests that the IR light is a combination of the secondary star plus contributions from two emitting poles. (author)

  3. Closed Paths of Light Trapped in a Closed Fermat Curve

    Dana-Picard, Thierry; Naiman, Aaron

    2002-01-01

    Geometric constructions have previously been shown that can be interpreted as rays of light trapped either in polygons or in conics, by successive reflections. The same question, trapping light in closed Fermat curves, is addressed here. Numerical methods are used to study the behaviour of the reflection points of a triangle when the degree of the…

  4. Automated Blazar Light Curves Using Machine Learning

    Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-07-27

    Every night in a remote clearing called Fenton Hill high in the Jemez Mountains of central New Mexico, a bank of robotically controlled telescopes tilt their lenses to the sky for another round of observation through digital imaging. Los Alamos National Laboratory’s Thinking Telescopes project is watching for celestial transients including high-power cosmic flashes called, and like all science, it can be messy work. To keep the project clicking along, Los Alamos scientists routinely install equipment upgrades, maintain the site, and refine the sophisticated machinelearning computer programs that process those images and extract useful data from them. Each week the system amasses 100,000 digital images of the heavens, some of which are compromised by clouds, wind gusts, focus problems, and so on. For a graduate student at the Lab taking a year’s break between master’s and Ph.D. studies, working with state-of-the-art autonomous telescopes that can make fundamental discoveries feels light years beyond the classroom.

  5. The hidden X-ray breaks in afterglow light curves

    Curran, P. A.; Wijers, R. A. M. J.; Horst, A. J. van der; Starling, R. L. C.

    2008-01-01

    Gamma-Ray Burst (GRB) afterglow observations in the Swift era have a perceived lack of achromatic jet breaks compared to the BeppoSAX, or pre-Swift era. Specifically, relatively few breaks, consistent with jet breaks, are observed in the X-ray light curves of these bursts. If these breaks are truly missing, it has serious consequences for the interpretation of GRB jet collimation and energy requirements, and the use of GRBs as standard candles.Here we address the issue of X-ray breaks which are possibly 'hidden' and hence the light curves are misinterpreted as being single power-laws. We show how a number of precedents, including GRB 990510 and GRB 060206, exist for such hidden breaks and how, even with the well sampled light curves of the Swift era, these breaks may be left misidentified. We do so by synthesising X-ray light curves and finding general trends via Monte Carlo analysis. Furthermore, in light of these simulations, we discuss how to best identify achromatic breaks in afterglow light curves via multi-wavelength analysis

  6. SPITZER SPACE TELESCOPE MID-IR LIGHT CURVES OF NEPTUNE

    Stauffer, John; Rebull, Luisa; Carey, Sean J.; Krick, Jessica; Ingalls, James G.; Lowrance, Patrick; Glaccum, William [Spitzer Science Center (SSC), California Institute of Technology, Pasadena, CA 91125 (United States); Marley, Mark S. [NASA Ames Research Center, Space Sciences and Astrobiology Division, MS245-3, Moffett Field, CA 94035 (United States); Gizis, John E. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Kirkpatrick, J. Davy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Simon, Amy A. [NASA Goddard Space Flight Center, Solar System Exploration Division (690.0), 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Wong, Michael H. [University of California, Department of Astronomy, Berkeley CA 94720-3411 (United States)

    2016-11-01

    We have used the Spitzer Space Telescope in 2016 February to obtain high cadence, high signal-to-noise, 17 hr duration light curves of Neptune at 3.6 and 4.5 μ m. The light curve duration was chosen to correspond to the rotation period of Neptune. Both light curves are slowly varying with time, with full amplitudes of 1.1 mag at 3.6 μ m and 0.6 mag at 4.5 μ m. We have also extracted sparsely sampled 18 hr light curves of Neptune at W1 (3.4 μ m) and W2 (4.6 μ m) from the Wide-feld Infrared Survey Explorer ( WISE )/ NEOWISE archive at six epochs in 2010–2015. These light curves all show similar shapes and amplitudes compared to the Spitzer light curves but with considerable variation from epoch to epoch. These amplitudes are much larger than those observed with Kepler / K 2 in the visible (amplitude ∼0.02 mag) or at 845 nm with the Hubble Space Telescope ( HST ) in 2015 and at 763 nm in 2016 (amplitude ∼0.2 mag). We interpret the Spitzer and WISE light curves as arising entirely from reflected solar photons, from higher levels in Neptune’s atmosphere than for K 2. Methane gas is the dominant opacity source in Neptune’s atmosphere, and methane absorption bands are present in the HST 763 and 845 nm, WISE W1, and Spitzer 3.6 μ m filters.

  7. Exploring Algorithms for Stellar Light Curves With TESS

    Buzasi, Derek

    2018-01-01

    The Kepler and K2 missions have produced tens of thousands of stellar light curves, which have been used to measure rotation periods, characterize photometric activity levels, and explore phenomena such as differential rotation. The quasi-periodic nature of rotational light curves, combined with the potential presence of additional periodicities not due to rotation, complicates the analysis of these time series and makes characterization of uncertainties difficult. A variety of algorithms have been used for the extraction of rotational signals, including autocorrelation functions, discrete Fourier transforms, Lomb-Scargle periodograms, wavelet transforms, and the Hilbert-Huang transform. In addition, in the case of K2 a number of different pipelines have been used to produce initial detrended light curves from the raw image frames.In the near future, TESS photometry, particularly that deriving from the full-frame images, will dramatically further expand the number of such light curves, but details of the pipeline to be used to produce photometry from the FFIs remain under development. K2 data offers us an opportunity to explore the utility of different reduction and analysis tool combinations applied to these astrophysically important tasks. In this work, we apply a wide range of algorithms to light curves produced by a number of popular K2 pipeline products to better understand the advantages and limitations of each approach and provide guidance for the most reliable and most efficient analysis of TESS stellar data.

  8. QUEST1 Variability Survey. III. Light Curve Catalog Update

    Rengstorf, A. W.; Thompson, D. L.; Mufson, S. L.; Andrews, P.; Honeycutt, R. K.; Vivas, A. K.; Abad, C.; Adams, B.; Bailyn, C.; Baltay, C.; Bongiovanni, A.; Briceño, C.; Bruzual, G.; Coppi, P.; Della Prugna, F.; Emmet, W.; Ferrín, I.; Fuenmayor, F.; Gebhard, M.; Hernández, J.; Magris, G.; Musser, J.; Naranjo, O.; Oemler, A.; Rosenzweig, P.; Sabbey, C. N.; Sánchez, Ge.; Sánchez, Gu.; Schaefer, B.; Schenner, H.; Sinnott, J.; Snyder, J. A.; Sofia, S.; Stock, J.; van Altena, W.

    2009-03-01

    This paper reports an update to the QUEST1 (QUasar Equatorial Survey Team, Phase 1) Variability Survey (QVS) light curve catalog, which links QVS instrumental magnitude light curves to Sloan Digital Sky Survey (SDSS) objects and photometry. In the time since the original QVS catalog release, the overlap between publicly available SDSS data and QVS data has increased by 8% in sky coverage and 16,728 in number of matched objects. The astrometric matching and the treatment of SDSS masks have been refined for the updated catalog. We report on these improvements and present multiple bandpass light curves, global variability information, and matched SDSS photometry for 214,941 QUEST1 objects. Based on observations obtained at the Llano del Hato National Astronomical Observatory, operated by the Centro de Investigaciones de Astronomía for the Ministerio de Ciencia y Tecnologia of Venezuela.

  9. Multiperiodicity in the light curve of Alpha Orionis

    Karovska, M.

    1987-01-01

    Alpha Ori, a supergiant star classified as M2 Iab, is characterized by pronounced variability encompassing most of its observed parameters. Variability on two different time scales has been observed in the light and velocity curves: a long period variation of about 6 years and superposed on this, irregular fluctuations having a time scale of several hundred days. This paper reports the results of Fourier analysis of more than 60- years of AAVSO (American Association of Variable Stars Observers) data which suggest a multiperiodicity in the light curve of α Ori

  10. A High Precision Approach to Calibrate a Structured Light Vision Sensor in a Robot-Based Three-Dimensional Measurement System

    Defeng Wu

    2016-08-01

    Full Text Available A robot-based three-dimensional (3D measurement system is presented. In the presented system, a structured light vision sensor is mounted on the arm of an industrial robot. Measurement accuracy is one of the most important aspects of any 3D measurement system. To improve the measuring accuracy of the structured light vision sensor, a novel sensor calibration approach is proposed to improve the calibration accuracy. The approach is based on a number of fixed concentric circles manufactured in a calibration target. The concentric circle is employed to determine the real projected centres of the circles. Then, a calibration point generation procedure is used with the help of the calibrated robot. When enough calibration points are ready, the radial alignment constraint (RAC method is adopted to calibrate the camera model. A multilayer perceptron neural network (MLPNN is then employed to identify the calibration residuals after the application of the RAC method. Therefore, the hybrid pinhole model and the MLPNN are used to represent the real camera model. Using a standard ball to validate the effectiveness of the presented technique, the experimental results demonstrate that the proposed novel calibration approach can achieve a highly accurate model of the structured light vision sensor.

  11. The Kepler Light Curves of AGN: A Detailed Analysis

    Smith, Krista Lynne; Mushotzky, Richard F.; Boyd, Patricia T.; Malkan, Matt; Howell, Steve B.; Gelino, Dawn M.

    2018-04-01

    We present a comprehensive analysis of 21 light curves of Type 1 active galactic nuclei (AGN) from the Kepler spacecraft. First, we describe the necessity and development of a customized pipeline for treating Kepler data of stochastically variable sources like AGN. We then present the light curves, power spectral density functions (PSDs), and flux histograms. The light curves display an astonishing variety of behaviors, many of which would not be detected in ground-based studies, including switching between distinct flux levels. Six objects exhibit PSD flattening at characteristic timescales that roughly correlate with black hole mass. These timescales are consistent with orbital timescales or free-fall accretion timescales. We check for correlations of variability and high-frequency PSD slope with accretion rate, black hole mass, redshift, and luminosity. We find that bolometric luminosity is anticorrelated with both variability and steepness of the PSD slope. We do not find evidence of the linear rms–flux relationships or lognormal flux distributions found in X-ray AGN light curves, indicating that reprocessing is not a significant contributor to optical variability at the 0.1%–10% level.

  12. Orbital Signatures from Observed Light Curves of Blazars

    2016-01-27

    Jan 27, 2016 ... Variability in active galactic nuclei is observed in UV to X-ray emission based light curves. This could be attributed to orbital signatures of the plasma that constitutes the accretion flow on the putative disk or in the developing jet close to the inner region of the central black hole. We discuss some theoretical ...

  13. The GO Cygni system: photoelectric observations and light curves analysis

    Rovithis, P.; Rovithis-Livaniou, H.; Niarchos, P.G.

    1990-01-01

    Photoelectric observations, in B and V, of the system GO Cygni obtained during 1985 at the Kryonerion Astronomical Station of the National Observatory of Greece are given. The corresponding light curves (typical β Lyrae) are analysed using Frequency Domain techniques. New photoelectric and absolute elements for the system are given, and its period was found to continue its increasing

  14. Photometric Observation and Light Curve Analysis of Binary System ...

    2016-01-27

    Jan 27, 2016 ... Photometric Observation and Light Curve Analysis of Binary System ER-Orionis ... February to April 2008 with the 51 cm telescope of Biruni Observatory of Shiraz University in U, B and V filters (Johnson system) and an RCA 4509 photomultiplier. ... Articles are also visible in Web of Science immediately.

  15. Photometric Observation and Light Curve Analysis of Binary System ...

    Abstract. Photometric observations of the over-contact binary ER ORI were performed during November 2007 and February to April 2008 with the 51cm telescope of Biruni Observatory of Shiraz University in U, B and V filters (Johnson system) and an RCA 4509 photomultiplier. We used these data to obtain the light curves ...

  16. The 1.4 GHZ light curve of GRB 970508

    Galama, TJ; Wijers, RAMJ; Groot, PJ; Strom, RG; De Bruyn, AG; Kouveliotou, C; Robinson, CR; van Paradus, J

    1998-01-01

    We report on Westerbork 1.4 GHz radio observations of the radio counterpart to gamma-ray burst GRB 970508, between 0.80 and 138 days after this event. The 1.4 GHz light curve shows a transition from optically thick to thin emission between 39 and 54 days after the event. We derive the slope p of the

  17. UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE

    Sanders, N. E.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Betancourt, M., E-mail: nsanders@cfa.harvard.edu [Department of Statistics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-02-10

    Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST.

  18. UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE

    Sanders, N. E.; Soderberg, A. M.; Betancourt, M.

    2015-01-01

    Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST

  19. Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

    Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

    2016-04-15

    A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

  20. Human Adolescent Phase Response Curves to Bright White Light.

    Crowley, Stephanie J; Eastman, Charmane I

    2017-08-01

    Older adolescents are particularly vulnerable to circadian misalignment and sleep restriction, primarily due to early school start times. Light can shift the circadian system and could help attenuate circadian misalignment; however, a phase response curve (PRC) to determine the optimal time for receiving light and avoiding light is not available for adolescents. We constructed light PRCs for late pubertal to postpubertal adolescents aged 14 to 17 years. Participants completed 2 counterbalanced 5-day laboratory sessions after 8 or 9 days of scheduled sleep at home. Each session included phase assessments to measure the dim light melatonin onset (DLMO) before and after 3 days of free-running through an ultradian light-dark (wake-sleep) cycle (2 h dim [~20 lux] light, 2 h dark). In one session, intermittent bright white light (~5000 lux; four 20-min exposures) was alternated with 10 min of dim room light once per day for 3 consecutive days. The time of light varied among participants to cover the 24-h day. For each individual, the phase shift to bright light was corrected for the free-run derived from the other laboratory session with no bright light. One PRC showed phase shifts in response to light start time relative to the DLMO and another relative to home sleep. Phase delay shifts occurred around the hours corresponding to home bedtime. Phase advances occurred during the hours surrounding wake time and later in the afternoon. The transition from delays to advances occurred at the midpoint of home sleep. The adolescent PRCs presented here provide a valuable tool to time bright light in adolescents.

  1. Interpretation of eclipsing light curves of dwarf novae

    Matvienko, A.N.; Cherepashchuk, A.M.; Yagola, A.G.

    1988-01-01

    The method for interpretation of eclipsing light curves of dwarf novae is proposed, taking into account the influence of the hot spot situated in the outer part of the disk-like envelope surrounding a white dwarf. This method is applied to the analysis of the eclipsing light curves of the system Z Cha in the quiet and active stages. It is shown that the optical luminosity of the hot spot in the system Z Cha in the active stage is 3-5 times greater than that in the quiet stage. Radius of the disk-like envelope in the active stage is more than twice greater than that in the quiet stage

  2. Light and velocity curve bumps for BW Vulpeculae

    Pesnell, W.D.; Cox, A.N.

    1980-01-01

    Bumps in the light and radial velocity curves of the Beta Cephei star BW Vulpeculae were modeled. Two mechanisms, a resonance phenomena and non-linear pulsations, were investigated. The resonance condition was clearly not fulfilled, the calculated period ratio being approximately 0.60, where a value of 0.50 L +- 0.03 is required for resonance. In the non-linear calculation, the bump appears, with the correct phase, but was found at an amplitude that is too large. Further, the light curve does not show any bump-like feature. The cause of the bump is the large spurious boost given the star's velocity field by the solution methods. The calculated periods of the stellar models are shorter than those of previous calculations, enhancing the possibility that these stars pulsate in a radial fundamental mode

  3. Preparation of Kepler light curves for asteroseismic analyses

    García, R.A.; Hekker, Saskia; Stello, Dennis

    2011-01-01

    The Kepler mission is providing photometric data of exquisite quality for the asteroseismic study of different classes of pulsating stars. These analyses place particular demands on the pre-processing of the data, over a range of time-scales from minutes to months. Here, we describe processing...... procedures developed by the Kepler Asteroseismic Science Consortium to prepare light curves that are optimized for the asteroseismic study of solar-like oscillating stars in which outliers, jumps and drifts are corrected....

  4. Candidate Binary Trojan and Hilda Asteroids from Rotational Light Curves

    Sonnett, Sarah M.; Mainzer, Amy K.; Grav, Tommy; Masiero, Joseph R.; Bauer, James M.; Kramer, Emily A.

    2017-10-01

    Jovian Trojans (hereafter, Trojans) are asteroids in stable orbits at Jupiter's L4 and L5 Lagrange points, and Hilda asteroids are inwards of the Trojans in 3:2 mean-motion resonance with Jupiter. Due to their special dynamical properties, observationally constraining the formation location and dynamical histories of Trojans and HIldas offers key input for giant planet migration models. A fundamental parameter in assessing formation location is the bulk density - with low-density objects associated with an ice-rich formation environment in the outer solar system and high-density objects typically linked to the warmer inner solar system. Bulk density can only be directly measured during a close fly-by or by determining the mutual orbits of binary asteroid systems. With the aim of determining densities for a statistically significant sample of Trojans and Hildas, we are undertaking an observational campaign to confirm and characterize candidate binary asteroids published in Sonnett et al. (2015). These objects were flagged as binary candidates because their large NEOWISE brightness variations imply shapes so elongated that they are not likely explained by a singular equilibrium rubble pile and instead may be two elongated, gravitationally bound asteroids. We are obtaining densely sampled rotational light curves of these possible binaries to search for light curve features diagnostic of binarity and to determine the orbital properties of any confirmed binary systems by modeling the light curve. We compare the We present an update on this follow-up campaign and comment on future steps.

  5. Pre-nebular Light Curves of SNe I

    Arnett, W. David [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Fryer, Christopher [Los Alamos National Laboratory, Los Alamos, NM (United States); Matheson, Thomas [National Optical Astronomy Observatory, Tucson, AZ (United States)

    2017-09-01

    We compare analytic predictions of supernova light curves with recent high-quality data from SN2011fe (Ia), KSN2011b (Ia), and the Palomar Transient Factory and the La Silla-QUEST variability survey (LSQ) (Ia). Because of the steady, fast cadence of observations, KSN2011b provides unique new information on SNe Ia: the smoothness of the light curve, which is consistent with significant large-scale mixing during the explosion, possibly due to 3D effects (e.g., Rayleigh–Taylor instabilities), and provides support for a slowly varying leakage (mean opacity). For a more complex light curve (SN2008D, SN Ib), we separate the luminosity due to multiple causes and indicate the possibility of a radioactive plume. The early rise in luminosity is shown to be affected by the opacity (leakage rate) for thermal and non-thermal radiation. A general derivation of Arnett’s rule again shows that it depends upon all processes heating the plasma, not just radioactive ones, so that SNe Ia will differ from SNe Ibc if the latter have multiple heating processes.

  6. Fourier analysis of the light curves of eclipsing variables. XV

    Demircan, O.

    1978-01-01

    A new general expression for the theoretical moments Asub(2m) of the light curves of eclipsing systems has been presented in the form of infinite series expansion. In this expansion, the terms have been given as the product of two different polynomials which satisfy certain three-term recursion formulae, and the coefficients diminish rapidly with increasing number of terms. Thus, the numerical values of the theoretical moments Asub(2m) can be generated recursively up to four significant figures for any given set of eclipse elements. This can be utilized to solve the eclipse elements in two ways: (i) with an indirect method, (ii) with a direct method as minimization to the observational moments Asub(2m) (area fitting). The procedures for obtaining the elements of any eclipsing system consisting of spherical stars have been automated by making use of the new expression for the moments Asub(2m) of the light curves. The theoretical functions f 0 , f 2 , f 4 , f 6 , g 2 and g 4 which are the functions of a and c 0 , have been used to solve the eclipse elements from the observed photometric data. The closed-form expressions for the functions f 2 , f 4 and f 6 have also been derived in terms of Kopal's I-integrals. The automated methods for obtaining the eclipse elements from one minimum alone have been tested on the light curves of YZ (21) Cassiopeiae under the spherical model assumptions. The results of these applications are given. (Auth.)

  7. Early light curves for Type Ia supernova explosion models

    Noebauer, U. M.; Kromer, M.; Taubenberger, S.; Baklanov, P.; Blinnikov, S.; Sorokina, E.; Hillebrandt, W.

    2017-12-01

    Upcoming high-cadence transient survey programmes will produce a wealth of observational data for Type Ia supernovae. These data sets will contain numerous events detected very early in their evolution, shortly after explosion. Here, we present synthetic light curves, calculated with the radiation hydrodynamical approach STELLA for a number of different explosion models, specifically focusing on these first few days after explosion. We show that overall the early light curve evolution is similar for most of the investigated models. Characteristic imprints are induced by radioactive material located close to the surface. However, these are very similar to the signatures expected from ejecta-CSM or ejecta-companion interaction. Apart from the pure deflagration explosion models, none of our synthetic light curves exhibit the commonly assumed power-law rise. We demonstrate that this can lead to substantial errors in the determination of the time of explosion. In summary, we illustrate with our calculations that even with very early data an identification of specific explosion scenarios is challenging, if only photometric observations are available.

  8. PAIR INSTABILITY SUPERNOVAE: LIGHT CURVES, SPECTRA, AND SHOCK BREAKOUT

    Kasen, Daniel; Woosley, S. E.; Heger, Alexander

    2011-01-01

    For the initial mass range (140 M sun sun ) stars die in a thermonuclear runaway triggered by the pair-production instability. The supernovae they make can be remarkably energetic (up to ∼10 53 erg) and synthesize considerable amounts of radioactive isotopes. Here we model the evolution, explosion, and observational signatures of representative pair instability supernovae (PI SNe) spanning a range of initial masses and envelope structures. The predicted light curves last for hundreds of days and range in luminosity from very dim to extremely bright (L ∼ 10 44 erg s -1 ). The most massive events are bright enough to be seen at high redshift, but the extended light curve duration (∼1 yr)-prolonged by cosmological time-dilation-may make it difficult to detect them as transients. A more promising approach may be to search for the brief and luminous outbreak occurring when the explosion shock wave first reaches the stellar surface. Using a multi-wavelength radiation-hydrodynamics code we calculate that, in the rest frame, the shock breakout transients of PI SNe reach luminosities of 10 45 -10 46 erg s -1 , peak at wavelengths ∼30-170 A, and last for several hours. We discuss how observations of the light curves, spectra, and breakout emission can be used to constrain the mass, radius, and metallicity of the progenitor.

  9. UBVRIz LIGHT CURVES OF 51 TYPE II SUPERNOVAE

    Galbany, Lluis; Hamuy, Mario; Jaeger, Thomas de; Moraga, Tania; González-Gaitán, Santiago; Gutiérrez, Claudia P.; Phillips, Mark M.; Morrell, Nidia I.; Thomas-Osip, Joanna; Suntzeff, Nicholas B.; Maza, José; González, Luis; Antezana, Roberto; Wishnjewski, Marina; Krisciunas, Kevin; Krzeminski, Wojtek; McCarthy, Patrick; Anderson, Joseph P.; Stritzinger, Maximilian; Folatelli, Gastón

    2016-01-01

    We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986–2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C and T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values

  10. UBVRIz LIGHT CURVES OF 51 TYPE II SUPERNOVAE

    Galbany, Lluis; Hamuy, Mario; Jaeger, Thomas de; Moraga, Tania; González-Gaitán, Santiago; Gutiérrez, Claudia P. [Millennium Institute of Astrophysics, Universidad de Chile (Chile); Phillips, Mark M.; Morrell, Nidia I.; Thomas-Osip, Joanna [Carnegie Observatories, Las Campanas Observatory, Casilla 60, La Serena (Chile); Suntzeff, Nicholas B. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Maza, José; González, Luis; Antezana, Roberto; Wishnjewski, Marina [Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Krisciunas, Kevin [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States); Krzeminski, Wojtek [N. Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa (Poland); McCarthy, Patrick [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Anderson, Joseph P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago (Chile); Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University (Denmark); Folatelli, Gastón, E-mail: lgalbany@das.uchile.cl [Instituto de Astrofísica de La Plata (IALP, CONICET) (Argentina); and others

    2016-02-15

    We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986–2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C and T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.

  11. Marginalizing Instrument Systematics in HST WFC3 Transit Light Curves

    Wakeford, H. R.; Sing, D. K.; Evans, T.; Deming, D.; Mandell, A.

    2016-03-01

    Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) infrared observations at 1.1-1.7 μm probe primarily the H2O absorption band at 1.4 μm, and have provided low-resolution transmission spectra for a wide range of exoplanets. We present the application of marginalization based on Gibson to analyze exoplanet transit light curves obtained from HST WFC3 to better determine important transit parameters such as Rp/R*, which are important for accurate detections of H2O. We approximate the evidence, often referred to as the marginal likelihood, for a grid of systematic models using the Akaike Information Criterion. We then calculate the evidence-based weight assigned to each systematic model and use the information from all tested models to calculate the final marginalized transit parameters for both the band-integrated and spectroscopic light curves to construct the transmission spectrum. We find that a majority of the highest weight models contain a correction for a linear trend in time as well as corrections related to HST orbital phase. We additionally test the dependence on the shift in spectral wavelength position over the course of the observations and find that spectroscopic wavelength shifts {δ }λ (λ ) best describe the associated systematic in the spectroscopic light curves for most targets while fast scan rate observations of bright targets require an additional level of processing to produce a robust transmission spectrum. The use of marginalization allows for transparent interpretation and understanding of the instrument and the impact of each systematic evaluated statistically for each data set, expanding the ability to make true and comprehensive comparisons between exoplanet atmospheres.

  12. Orbital Light Curves of UU Aquarii in Stunted Outburst

    Robertson, J. W.; Honeycutt, R. K.; Henden, A. A.; Campbell, R. T.

    2018-02-01

    Stunted outbursts are ∼0.ͫ6 eruptions, typically lasting 5–10 days, which are found in some novalike cataclysmic variables, including UU Aqr. The mechanism responsible for stunted outbursts is uncertain but is likely related to an accretion disk instability or to variations in the mass transfer rate. A campaign to monitor the eclipse light curves in UU Aqr has been conducted in order to detect any light curve distortions due to the appearance of a hot spot on the disk at the location of the impact point of the accretion stream. If stunted outbursts are due to a temporary mass transfer enhancement, then predictable deformations of the orbital light curve are expected to occur during such outbursts. This study used 156 eclipses on 135 nights during the years 2000–2012. During this interval, random samples found the system to be in stunted outbursts 4%–5% of the time, yielding ∼7 eclipses obtained during some stage of stunted outburst. About half of the eclipses obtained during stunted outbursts showed clear evidence for hot spot enhancement, providing strong evidence that the stunted outbursts in UU Aqr are associated with mass transfer variations. The other half of the eclipses during stunted outburst showed little or no evidence for hot spot enhancement. Furthermore, there were no systematic changes in the hot spot signature as stunted outbursts progressed. Therefore, we have tentatively attributed the changes in hot spot visibility during stunted outburst to random blobby accretion, which likely further modulates the strength of the accretion stream on orbital timescales.

  13. DETERMINISTIC COMPONENTS IN THE LIGHT CURVE AMPLITUDE OF Y OPH

    Pop, Alexandru; Turcu, Vlad; Vamos, Calin

    2010-01-01

    About two decades after the discovery of the amplitude decline of the light curve of the classical Cepheid Y Oph, its study is resumed using an increased amount of homogenized data and an extended time base. In our approach, the investigation of different time series concerning the light curve amplitude of Y Oph is not only the reason for the present study, but also a stimulus for developing a coherent methodology for studying long- and short-term variability phenomena in variable stars, taking into account the details of concrete observing conditions: amount of data, data sampling, time base, and individual errors of observational data. The statistical significance of this decreasing trend was estimated by assuming its linearity. We approached the decision-making process by formulating adequate null and alternative hypotheses, and testing the value of the regression line slope for different data sets via Monte Carlo simulations. A variability analysis, through various methods, of the original data and of the residuals obtained after removing the linear trend was performed. We also proposed a new statistical test, based on amplitude spectrum analysis and Monte Carlo simulations, intended to evaluate how detectible is a given (linear) trend in well-defined observing conditions: the trend detection probability. The main conclusion of our study on Y Oph is that, even if the false alarm probability is low enough to consider the decreasing trend to be statistically significant, the available data do not allow us to obtain a reasonably powerful test. We are able to confirm the light curve amplitude decline, and the order of magnitude of its slope with a better statistical substantiation. According to the obtained values of the trend detection probability, it seems that the trend we are dealing with is marked by a low detectibility. Our attempt to find signs of possible variability phenomena at shorter timescales ended by emphasizing the relative constancy of our data

  14. Testing the stationarity of white dwarf light-curves

    Molnar, L; Kollath, Z; Plachy, E; Paparo, M

    2009-01-01

    Long period white dwarfs show changes in their frequency spectra from one observing season to another, i.e. their light-curves cannot be considered as stationary multiperiodic variations on long timescales. However, due to the complex frequency spectra of these stars and the narrow frequency spacing, it is still unknown, what the shortest time scale is, where real physical modulation exists. We present tests on artificial data, resembling the observations, using time-frequency distributions (TFDs), Fourier-analysis and the analytical signal method.

  15. Dependence on supernovae light-curve processing in void models

    Bengochea, Gabriel R., E-mail: gabriel@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); De Rossi, Maria E., E-mail: derossi@iafe.uba.ar [Instituto de Astronomía y Física del Espacio (IAFE), UBA-CONICET, CC 67, Suc. 28, 1428 Buenos Aires (Argentina); Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)

    2014-06-02

    In this work, we show that when supernova Ia (SN Ia) data sets are used to put constraints on the free parameters of inhomogeneous models, certain extra information regarding the light-curve fitter used in the supernovae Ia luminosity fluxes processing should be taken into account. We found that the size of the void as well as other parameters of these models might be suffering extra degenerations or additional systematic errors due to the fitter. A recent proposal to relieve the tension between the results from Planck satellite and SNe Ia is re-analyzed in the framework of these subjects.

  16. Statistical analysis of the W Cyg light curve

    Klyus, I.A.

    1983-01-01

    A statistical analysis of the light curve of W Cygni has been carried out. The process of brightness variations brightness of the star is shown to be a stationary stochastic one. The hypothesis of stationarity of the process was checked at the significance level of α=0.05. Oscillations of the brightness with average durations of 131 and 250 days have been found. It is proved that oscillations are narrow-band noise, i.e. cycles. Peaks on the power spectrum corresponding to these cycles exceed 99% confidence interval. It has been stated that the oscillations are independent

  17. A new approach to the analysis of Mira light curves

    Mennessier, M.O.; Barthes, D.; Mattei, J.A.

    1990-01-01

    Two different but complementary methods for predicting Mira luminosities are presented. One method is derived from a Fourier analysis, it requires performing deconvolution, and its results are not certain due to the inherent instability of deconvolution problems. The other method is a learning method utilizing artificial intelligence techniques where a light curve is presented as an ordered sequence of pseudocycles, and rules are learned by linking the characteristics of several consecutive pseudocycles to one characteristic of the future cycle. It is observed that agreement between these methods is obtainable when it is possible to eliminate similar false frequencies from the preliminary power spectrum and to improve the degree of confidence in the rules

  18. High precision redundant robotic manipulator

    Young, K.K.D.

    1998-01-01

    A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns. 3 figs

  19. Flare Characteristics from X-ray Light Curves

    Gryciuk, M.; Siarkowski, M.; Sylwester, J.; Gburek, S.; Podgorski, P.; Kepa, A.; Sylwester, B.; Mrozek, T.

    2017-06-01

    A new methodology is given to determine basic parameters of flares from their X-ray light curves. Algorithms are developed from the analysis of small X-ray flares occurring during the deep solar minimum of 2009, between Solar Cycles 23 and 24, observed by the Polish Solar Photometer in X-rays (SphinX) on the Complex Orbital Observations Near-Earth of Activity of the Sun-Photon (CORONAS- Photon) spacecraft. One is a semi-automatic flare detection procedure that gives start, peak, and end times for single ("elementary") flare events under the assumption that the light curve is a simple convolution of a Gaussian and exponential decay functions. More complex flares with multiple peaks can generally be described by a sum of such elementary flares. Flare time profiles in the two energy ranges of SphinX (1.16 - 1.51 keV, 1.51 - 15 keV) are used to derive temperature and emission measure as a function of time during each flare. The result is a comprehensive catalogue - the SphinX Flare Catalogue - which contains 1600 flares or flare-like events and is made available for general use. The methods described here can be applied to observations made by Geosynchronous Operational Environmental Satellites (GOES), the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and other broad-band spectrometers.

  20. SIMULATED PERFORMANCE OF TIMESCALE METRICS FOR APERIODIC LIGHT CURVES

    Findeisen, Krzysztof; Hillenbrand, Lynne [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Cody, Ann Marie, E-mail: krzys@astro.caltech.edu [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States)

    2015-01-10

    Aperiodic variability is a characteristic feature of young stars, massive stars, and active galactic nuclei. With the recent proliferation of time-domain surveys, it is increasingly essential to develop methods to quantify and analyze aperiodic variability. We develop three timescale metrics that have been little used in astronomy—Δm-Δt plots, peak-finding, and Gaussian process regression—and present simulations comparing their effectiveness across a range of aperiodic light curve shapes, characteristic timescales, observing cadences, and signal to noise ratios. We find that Gaussian process regression is easily confused by noise and by irregular sampling, even when the model being fit reflects the process underlying the light curve, but that Δm-Δt plots and peak-finding can coarsely characterize timescales across a broad region of parameter space. We make public the software we used for our simulations, both in the spirit of open research and to allow others to carry out analogous simulations for their own observing programs.

  1. Machine Learning Techniques for Stellar Light Curve Classification

    Hinners, Trisha A.; Tat, Kevin; Thorp, Rachel

    2018-07-01

    We apply machine learning techniques in an attempt to predict and classify stellar properties from noisy and sparse time-series data. We preprocessed over 94 GB of Kepler light curves from the Mikulski Archive for Space Telescopes (MAST) to classify according to 10 distinct physical properties using both representation learning and feature engineering approaches. Studies using machine learning in the field have been primarily done on simulated data, making our study one of the first to use real light-curve data for machine learning approaches. We tuned our data using previous work with simulated data as a template and achieved mixed results between the two approaches. Representation learning using a long short-term memory recurrent neural network produced no successful predictions, but our work with feature engineering was successful for both classification and regression. In particular, we were able to achieve values for stellar density, stellar radius, and effective temperature with low error (∼2%–4%) and good accuracy (∼75%) for classifying the number of transits for a given star. The results show promise for improvement for both approaches upon using larger data sets with a larger minority class. This work has the potential to provide a foundation for future tools and techniques to aid in the analysis of astrophysical data.

  2. Fourier analysis of the light curves of eclipsing variables, XXIV

    Edalati, M.T.

    1978-01-01

    The aim of the present paper will be to evaluate numerically Jacobian and other functions which have been discussed in more detail in a previous paper of this series, and also choose the most convenient moments to obtain a good determination for the unknown eclipse parameters a and c 0 . More than 12 different pairs of g-functions for real values of m have been investigated numerically and diagrammatically. The behaviour of g-functions depends but very little on different combination of the moments, and related diagrams are approximately the same as g 2 and g 4 . The behaviour of the vanishing Jacobian, arising from different pairs of g-functions for real values of m>= 0 . Accordingly, the author obtains the optimum combination of the moments (i.e., A 6 , A 7 , A 8 and A 9 ) in g-functions g 7 and g 8 . It has been noted that the behaviour of the g-functions which depend on the combinations of the higher order moments (i.e., m>= 5) have been ruled out, because the proportional error of the moments Asub(2m) increases with increasing values of real m. The automated method has been tested successfully on the light curve of RT Per. Finally, a comparison is given of the elements of RT Per arising from two different pairs of g-functions, i.e. g 2 , g 4 and g 7 , g 8 for the light curves analysis. (Auth.)

  3. A Semiautomatic Pipeline for Be Star Light Curves

    Rímulo, L. R.; Carciofi, A. C.; Rivinius, T.; Okazaki, A.

    2016-11-01

    Observational and theoretical studies from the last decade have shown that the Viscous Decretion Disk (VDD) scenario, in which turbulent viscosity is the physical mechanism responsible for the transport of material and angular momentum ejected from the star to the outer regions of the disk, is the only viable model for explaining the circumstellar disks of Be stars. In the α-disk approach applied to the VDD, the dimensionless parameter α is a measure of the turbulent viscosity. Recently, combining the time-dependent evolution of a VDD α-disk with non-LTE radiative transfer calculations, the first measurement of the α parameter was made, for the disk dissipation of the Be star ω CMa. It was found that α≍ 1 for that Be disk. The main motivation of this present work is the statistical determination of the α parameter. For this purpose, we present a pipeline that will allow the semiautomatic determination of the α parameter of several dozens of light curves of Be stars available from photometric surveys, In this contribution, we describe the pipeline, outlining the main staps required for the semiautomatic analysis of light curves

  4. SIMULATED PERFORMANCE OF TIMESCALE METRICS FOR APERIODIC LIGHT CURVES

    Findeisen, Krzysztof; Hillenbrand, Lynne; Cody, Ann Marie

    2015-01-01

    Aperiodic variability is a characteristic feature of young stars, massive stars, and active galactic nuclei. With the recent proliferation of time-domain surveys, it is increasingly essential to develop methods to quantify and analyze aperiodic variability. We develop three timescale metrics that have been little used in astronomy—Δm-Δt plots, peak-finding, and Gaussian process regression—and present simulations comparing their effectiveness across a range of aperiodic light curve shapes, characteristic timescales, observing cadences, and signal to noise ratios. We find that Gaussian process regression is easily confused by noise and by irregular sampling, even when the model being fit reflects the process underlying the light curve, but that Δm-Δt plots and peak-finding can coarsely characterize timescales across a broad region of parameter space. We make public the software we used for our simulations, both in the spirit of open research and to allow others to carry out analogous simulations for their own observing programs

  5. The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation

    Harpsøe, Kennet Bomann West; Hardis, S.; Hinse, T. C.

    2012-01-01

    Aims: We present 11 high-precision photometric transit observations of the transiting super-Earth planet GJ1214b. Combining these data with observations from other authors, we investigate the ephemeris for possible signs of transit timing variations (TTVs) using a Bayesian approach. Methods......: The observations were obtained using telescope-defocusing techniques, and achieve a high precision with random errors in the photometry as low as 1mmag per point. To investigate the possibility of TTVs in the light curve, we calculate the overall probability of a TTV signal using Bayesian methods. Results...

  6. Common Envelope Light Curves. I. Grid-code Module Calibration

    Galaviz, Pablo; Marco, Orsola De; Staff, Jan E.; Iaconi, Roberto [Department of Physics and Astronomy, Macquarie University, Sydney, NSW (Australia); Passy, Jean-Claude, E-mail: Pablo.Galaviz@me.com [Argelander-Institut für Astronomie, Auf dem Hügel 71, D-53121 Bonn (Germany)

    2017-04-01

    The common envelope (CE) binary interaction occurs when a star transfers mass onto a companion that cannot fully accrete it. The interaction can lead to a merger of the two objects or to a close binary. The CE interaction is the gateway of all evolved compact binaries, all stellar mergers, and likely many of the stellar transients witnessed to date. CE simulations are needed to understand this interaction and to interpret stars and binaries thought to be the byproduct of this stage. At this time, simulations are unable to reproduce the few observational data available and several ideas have been put forward to address their shortcomings. The need for more definitive simulation validation is pressing and is already being fulfilled by observations from time-domain surveys. In this article, we present an initial method and its implementation for post-processing grid-based CE simulations to produce the light curve so as to compare simulations with upcoming observations. Here we implemented a zeroth order method to calculate the light emitted from CE hydrodynamic simulations carried out with the 3D hydrodynamic code Enzo used in unigrid mode. The code implements an approach for the computation of luminosity in both optically thick and optically thin regimes and is tested using the first 135 days of the CE simulation of Passy et al., where a 0.8  M {sub ⊙} red giant branch star interacts with a 0.6  M {sub ⊙} companion. This code is used to highlight two large obstacles that need to be overcome before realistic light curves can be calculated. We explain the nature of these problems and the attempted solutions and approximations in full detail to enable the next step to be identified and implemented. We also discuss our simulation in relation to recent data of transients identified as CE interactions.

  7. Ultraviolet light curves of U Geminorum and VW Hydri

    Wu, C.-C.; Panek, R.J.; Holm, A.V.; Schiffer, F.H. III

    1982-01-01

    Ultraviolet light curves have been obtained for the quiescent dwarf novae U Gem and VW Hyi. The amplitude of the hump associated with the accretion hot spot is much smaller in the UV than in the visible. This implies that the bright spot temperature is roughly 12000 K if it is optically thick. A hotter spot would have to be optically thin in the near UV. The flux distribution of U Gem in quiescence cannot be fitted by model spectra of steady state, viscous accretion disks. The absolute luminosity, the flux distribution, and the far UV spectrum suggest that the primary star is visible in the far UV. The optical-UV flux distribution of VW Hyi could be matched roughly by the authors' model accretion disks, but the fitting is poorly constrained due to the uncertainty in its distance. (Auth.)

  8. Supernova light-curve fitters and dark energy

    Bengochea, Gabriel R., E-mail: gabriel@iafe.uba.a [Instituto de Astronomia y Fisica del Espacio (IAFE), CC 67, Suc. 28, 1428 Buenos Aires (Argentina)

    2011-01-24

    We show that when a procedure is made to remove the tension between a supernova Ia (SN Ia) data set and observations from BAO and CMB, there might be the case where the same SN Ia set built with two different light-curve fitters behaves as two separate and distinct supernova sets, and the tension found by some authors between supernova sets actually could be due to tension or inconsistency between fitters. We also show that the information of the fitter used in an SN Ia data set could be relevant to determine whether phantom type models are favored or not when such a set is combined with the BAO/CMB joint parameter.

  9. Secondary eclipses in the CoRoT light curves

    Belmonte Juan Antonio

    2013-04-01

    Full Text Available We identify and characterize secondary eclipses in the original light curves of published CoRoT planets using uniform detection and evaluation criteria. Our analysis is based on a Bayesian statistics: the eclipse search is carried out using Bayesian model selection, and the characterization of the plausible eclipse candidates using Bayesian parameter estimation. We discover statistically significant eclipse events for two planets, CoRoT-6b and CoRoT-11b, and for one brown dwarf, CoRoT-15b. We also find marginally significant eclipse events passing our plausibility criteria for CoRoT-3b, 13b, 18b, and 21b, and confirm the previously published CoRoT-1b and CoRoT-2b eclipses.

  10. Supernova light-curve fitters and dark energy

    Bengochea, Gabriel R.

    2011-01-01

    We show that when a procedure is made to remove the tension between a supernova Ia (SN Ia) data set and observations from BAO and CMB, there might be the case where the same SN Ia set built with two different light-curve fitters behaves as two separate and distinct supernova sets, and the tension found by some authors between supernova sets actually could be due to tension or inconsistency between fitters. We also show that the information of the fitter used in an SN Ia data set could be relevant to determine whether phantom type models are favored or not when such a set is combined with the BAO/CMB joint parameter.

  11. Low mass SN Ia and the late light curve

    Colgate, S.A.; Fryer, C.L.

    1995-01-01

    The late bolometric light curves of type Ia supernovae, when measured accurately over several years, show an exponential decay with a 56d half-life over a drop in luminosity of 8 magnitudes (10 half-lives). The late-time light curve is thought to be governed by the decay of Co 56 , whose 77d half-life must then be modified to account for the observed decay time. Two mechanisms, both relying upon the positron fraction of the Co 56 decay, have been proposed to explain this modification. One explanation requires a large amount of emission at infra-red wavelengths where it would not be detected. The other explanation has proposed a progressive transparency or leakage of the high energy positrons (Colgate, Petschek and Kriese, 1980). For the positrons to leak out of the expanding nebula at the required rate necessary to produce the modified 56d exponential, the mass of the ejecta from a one foe (10 51 erg in kinetic energy) explosion must be small, M ejec = 0.4M circle-dot with M ejec ∝ KE 0.5 . Thus, in this leakage explanation, any reasonable estimate of the total energy of the explosion requires that the ejected mass be very much less than the Chandrasekhar mass of 1.4M circle-dot . This is very difficult to explain with the ''canonical'' Chandrasekhar-mass thermonuclear explosion that disintegrates the original white dwarf star. This result leads us to pursue alternate mechanisms of type Ia supernovae. These mechanisms include sub-Chandrasekhar thermonuclear explosions and the accretion induced collapse of Chandrasekhar mass white dwarfs. We will summarize the advantages and disadvantages of both mechanisms with considerable detail spent on our new accretion induced collapse simulations. These mechanisms lead to lower Ni 56 production and hence result in type Ia supernovae with luminosities decreased down to ∼ 50% that predicted by the ''standard'' model

  12. VizieR Online Data Catalog: V346 Cen multiwavelength light curves (Mayer+, 2016)

    Mayer, P.; Harmanec, P.; Wolf, M.; Nemravova, J.; Prsa, A.; Fremat, Y.; Zejda, M.; Liska, J.; Jurysek, J.; Honkova, K.; Masek, M.

    2016-06-01

    We present photographic light curves from O'Connell (1939, Publications of the Riverview College Observatory, 2, 5), uvby light curves from Gimenez et al. (1986A&AS...66...45G), BVR light curves from 0.6 m reflector with a CCD camera, Mt. John, New Zealand, green light curve from Sonnar 4/135mm telephoto lens with a CCD ATIK16IC camera, Sutherland, South Africa and BVRI light curves from 0.3m Meade Schmidt-Cassegrain reflector with a CCD camera. (5 data files).

  13. Supervised detection of anomalous light curves in massive astronomical catalogs

    Nun, Isadora; Pichara, Karim; Protopapas, Pavlos; Kim, Dae-Won

    2014-01-01

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  14. Supervised Detection of Anomalous Light Curves in Massive Astronomical Catalogs

    Nun, Isadora; Pichara, Karim; Protopapas, Pavlos; Kim, Dae-Won

    2014-09-01

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  15. Vaporization of comet nuclei: Light curves and life times

    Cowan, J J [Harvard Univ., Cambridge, MA (USA). Center for Astrophysics; A' Hearn, M F [Maryland Univ., College Park (USA)

    1979-10-01

    The authors have examined the effects of vaporization from the nucleus of a comet and show that a latitude dependence of vaporization can, in some cases, explain asymmetries in commetary light curves. They also find that a non-uniform distribution of solar radiation over a comet can considerably shorten the vaporization lifetime compared to the results normally obtained by assuming that the nuclear surface is isothermal. Independent of any latitude effects, comets with CO/sub 2/-dominated nuclei and with periherlion distances less than 0.5 AU have vaporization lifetimes less than or comparable to their dynamical ejection times. This may explain the observed deficit of comets with small perihelion distances. Similarly comets with CO/sub 2/-dominated nuclei and perihelia near Jupiter's orbit have vaporization lifetimes that are shorter than the time for capture into short-period orbits. They suggest, therefore, that at least some new comets are composed in large part of CO/sub 2/, while only H/sub 2/O-dominated comets, with lower vaporization rates, can survive to be captured into short-period orbits.

  16. High precision timing in a FLASH

    Hoek, Matthias; Cardinali, Matteo; Dickescheid, Michael; Schlimme, Soeren; Sfienti, Concettina; Spruck, Bjoern; Thiel, Michaela [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)

    2016-07-01

    A segmented highly precise start counter (FLASH) was designed and constructed at the Institute for Nuclear Physics in Mainz. Besides determining a precise reference time, a Time-of-Flight measurement can be performed with two identical FLASH units. Thus, particle identification can be provided for mixed hadron beam environments. The detector design is based on the detection of Cherenkov light produced in fused silica radiator bars with fast multi-anode MCP-PMTs. The segmentation of the radiator improves the timing resolution while allowing a coarse position resolution along one direction. Both, the arrival time and the Time-over-Threshold are determined by the readout electronics, which enables walk correction of the arrival time. The performance of two FLASH units was investigated in test experiments at the Mainz Microton (MAMI) using an electron beam with an energy of 855 MeV and at CERN's PS T9 beam line with a mixed hadron beam with momenta between 3-8 GeV/c. Effective Time-walk correction methods based on Time-over-Threshold were developed for the data analysis. The achieved Time-Of-Flight resolution after applying all corrections was found to be 70 ps. Furthermore, the PID and position resolution capabilities are discussed in this contribution.

  17. RADIOACTIVELY POWERED RISING LIGHT CURVES OF TYPE Ia SUPERNOVAE

    Piro, Anthony L.

    2012-01-01

    The rising luminosity of the recent, nearby supernova 2011fe shows a quadratic dependence with time during the first ≈0.5-4 days. In addition, studies of the composite light curves formed from stacking together many Type Ia supernovae (SNe Ia) have found similar power-law indices for the rise, but may also show some dispersion that may indicate diversity. I explore what range of power-law rises are possible due to the presence of radioactive material near the surface of the exploding white dwarf (WD). I summarize what constraints such a model places on the structure of the progenitor and the distribution and velocity of ejecta. My main conclusion is that for the inferred explosion time for SN 2011fe, its rise requires an increasing mass fraction X 56 ≈ (4-6) × 10 –2 of 56 Ni distributed between a depth of ≈10 –2 and 0.3 M ☉ below the WD's surface. Radioactive elements this shallow are not found in simulations of a single C/O detonation. Scenarios that may produce this material include helium-shell burning during a double-detonation ignition, a gravitationally confined detonation, and a subset of deflagration to detonation transition models. In general, the power-law rise can differ from quadratic depending on the details of the velocity, density, and radioactive deposition gradients in a given event. Therefore, comparisons of this work with observed bolometric rises of SNe Ia would place strong constraints on the properties of the shallow outer layers, providing important clues for identifying the elusive progenitors of SNe Ia.

  18. Intensive Monitoring Survey of Nearby Galaxies (IMSNG): Catching Early Light Curves of Supernovae

    Im, Myungshin; IMSNG Team

    2018-01-01

    SNe light curves have been used to study the expansion history of the universe, and a lot of efforts have gone into understanding the overall shape of the radioactively powered light curve. However, we still have little direct observational evidence for the theorized SN progenitor systems. Recent studies suggest that the light curve of a supernova shortly after its explosion (world. Through this survey, we expect to catch the very early precursor emission as faint as R=21 mag (~0.1 Rsun for the progenitor). This poster outlines this project, and present a few scientific highlights, such as the early light curve of SN 2015F in NGC 2442.

  19. Exquisite Nova Light Curves from the Solar Mass Ejection Imager (SMEI)

    Hounsell, R.; Bode, M. F.; Hick, P. P.; Buffington, A.; Jackson, B. V.; Clover, J. M.; Shafter, A. W.; Darnley, M. J.; Mawson, N. R.; Steele, I. A.; Evans, A.; Eyres, S. P. S.; O'Brien, T. J.

    2010-01-01

    We present light curves of three classical novae (KT Eridani, V598 Puppis, V1280 Scorpii) and one recurrent nova (RS Ophiuchi) derived from data obtained by the Solar Mass Ejection Imager (SMEI) on board the Coriolis satellite. SMEI provides near complete sky-map coverage with precision visible-light photometry at 102-minute cadence. The light curves derived from these sky maps offer unprecedented temporal resolution around, and especially before, maximum light, a phase of the nova eruption n...

  20. Fourier techniques for an analysis of eclipsing binary light curves. Pt. 6b

    Demircan, O.

    1980-01-01

    This is a continuation of a previous paper which appeared in this journal (Demircan, 1980b) and aims at ascertaining some other relations between the integral transforms of the light curves of eclipsing binary systems. The appropriate use of these relations should facilitate the numerical computations for an analysis of eclipsing binary light curves by different Fourier techniques. (orig.)

  1. Infrared and optical light curves of EX Hydrae and VW Hydri

    Sherrington, M.R.; Lawson, P.A.; King, A.R.; Jameson, R.F.

    1980-01-01

    Optical and infrared light curves of EX Hya (V and K) and VW Hyi (J and K) are presented. The infrared colours imply very large discs for these systems. It is also found for EX Hya that the structure of the light curves is non-repeatable. (author)

  2. Application of Geodetic VLBI Data to Obtaining Long-Term Light Curves for Astrophysics

    Kijima, Masachika

    2010-01-01

    The long-term light curve is important to research on binary black holes and disk instability in AGNs. The light curves have been drawn mainly using single dish data provided by the University of Michigan Radio Observatory and the Metsahovi Radio Observatory. Hence, thus far, we have to research on limited sources. I attempt to draw light curves using VLBI data for those sources that have not been monitored by any observatories with single dish. I developed software, analyzed all geodetic VLBI data available at the IVS Data Centers, and drew the light curves at 8 GHz. In this report, I show the tentative results for two AGNs. I compared two light curves of 4C39.25, which were drawn based on single dish data and on VLBI data. I confirmed that the two light curves were consistent. Furthermore, I succeeded in drawing the light curve of 0454-234 with VLBI data, which has not been monitored by any observatory with single dish. In this report, I suggest that the geodetic VLBI archive data is useful to obtain the long-term light curves at radio bands for astrophysics.

  3. Four-colour photometry of eclipsing binaries. XXXII. Light curves of V1031 Orionis

    Clausen, J V; Nordstroem, B; Andersen, J [Copenhagen Univ. Observatory, (DK); Nordstroem, B; Andersen, J [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (US)

    1989-12-01

    Complete uvby light curves are presented for the bright, southern, A-type triple system V1031 Orionis which consists of two well-separated eclipsing components in a circular orbit and a third component at an angular distance of about 0.16 sec. The light curves contain 1280 points in each colour, obtained from 1980 to 1983.

  4. Four-colour photometry of eclipsing binaries. XXXII. Light curves of V1031 Orionis

    Clausen, J.V.; Nordstroem, B.; Andersen, J.; Nordstroem, B.; Andersen, J.

    1989-01-01

    Complete uvby light curves are presented for the bright, southern, A-type triple system V1031 Orionis which consists of two well-separated eclipsing components in a circular orbit and a third component at an angular distance of about 0.16 sec. The light curves contain 1280 points in each colour, obtained from 1980 to 1983

  5. Generalized Fermat's principle and action for light rays in a curved spacetime

    Frolov, Valeri P.

    2013-09-01

    We start with formulation of the generalized Fermat’s principle for light propagation in a curved spacetime. We apply Pontryagin’s minimum principle of the optimal control theory and obtain an effective Hamiltonian for null geodesics in a curved spacetime. We explicitly demonstrate that dynamical equations for this Hamiltonian correctly reproduce null geodesic equations. Other forms of the action for light rays in a curved spacetime are also discussed.

  6. CSI 2264: CHARACTERIZING YOUNG STARS IN NGC 2264 WITH STOCHASTICALLY VARYING LIGHT CURVES

    Stauffer, John; Rebull, Luisa; Carey, Sean [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Kepler Science Office, Mountain View, CA 94035 (United States); Hillenbrand, Lynne A.; Carpenter, John [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Terebey, Susan [Department of Physics and Astronomy, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Morales-Calderón, Maria [Centro de Astrobiología, Dpto. de Astrofísica, INTA-CSIC, P.O. BOX 78, E-28691, ESAC Campus, Villanueva de la Cañada, Madrid (Spain); Alencar, Silvia H. P.; McGinnis, Pauline; Sousa, Alana [Departamento de Física—ICEx—UFMG, Av. Antônio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Bouvier, Jerome; Venuti, Laura [Université de Grenoble, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), F-38000 Grenoble (France); Hartmann, Lee; Calvet, Nuria [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI:48105 (United States); Micela, Giusi; Flaccomio, Ettore [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134, Palermo (Italy); Song, Inseok [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602-2451 (United States); Gutermuth, Rob, E-mail: stauffer@ipac.caltech.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); and others

    2016-03-15

    We provide CoRoT and Spitzer light curves and other supporting data for 17 classical T Tauri stars in NGC 2264 whose CoRoT light curves exemplify the “stochastic” light curve class as defined in 2014 by Cody et al. The most probable physical mechanism to explain the optical variability within this light curve class is time-dependent mass accretion onto the stellar photosphere, producing transient hot spots. Where we have appropriate spectral data, we show that the veiling variability in these stars is consistent in both amplitude and timescale with the optical light curve morphology. The veiling variability is also well-correlated with the strength of the He i 6678 Å emission line, predicted by models to arise in accretion shocks on or near the stellar photosphere. Stars with accretion burst light curve morphology also have variable mass accretion. The stochastic and accretion burst light curves can both be explained by a simple model of randomly occurring flux bursts, with the stochastic light curve class having a higher frequency of lower amplitude events. Members of the stochastic light curve class have only moderate mass accretion rates. Their Hα profiles usually have blueshifted absorption features, probably originating in a disk wind. The lack of periodic signatures in the light curves suggests that little of the variability is due to long-lived hot spots rotating into or out of our line of sight; instead, the primary driver of the observed photometric variability is likely to be instabilities in the inner disk that lead to variable mass accretion.

  7. UBV Light Curves of ζ AUR Star 32 Cygni

    Il-Seong Nha

    1992-12-01

    Full Text Available UBV ovservation of ζ Aur star 32 Cyg have been at the Yonsei University Observatory suing the 60-cm Goto reflector and five years, 1988-1992. Observations made during these years cover outside of eclipse phase only. No significant light variation which would represent the secondary eclipse of red supergiant by a hot main sequence star is found. The light levels in three passbands do not show any evidence of the proximate effect of this binary system. Some strong light variations, particularly in U, are discussed with no successful explanation.

  8. LONG-TERM LIGHT CURVE OF HIGHLY VARIABLE PROTOSTELLAR STAR GM CEP

    Xiao Limin; Kroll, Peter; Henden, Arne A.

    2010-01-01

    We present data from the archival plates at Harvard College Observatory and Sonneberg Observatory showing the field of the solar-type pre-main-sequence star GM Cep. A total of 186 magnitudes of GM Cep have been measured on these archival plates, with 176 in blue sensitivity, six in visible, and four in red. We combine our data with data from the literature and from the American Association of Variable Star Observers to depict the long-term light curves of GM Cep in both B and V wavelengths. The light curves span from 1895 until now, with two densely sampled regions (1935-1945 in the B band, and 2006 until now in the V band). The long-term light curves do not show any fast rise behavior as predicted by an accretion mechanism. Both the light curves and the magnitude histograms confirm the conclusion that the light curves are dominated by dips (possibly from extinction) superposed on some quiescence state, instead of outbursts caused by accretion flares. Our result excludes the possibility of GM Cep being a FUor, EXor, or McNeil's Nebula-type star. Several special cases of T Tauri stars were checked, but none of these light curves were compatible with that of GM Cep. The lack of periodicity in the light curve excludes the possibility of GM Cep being a KH 15D system.

  9. NEPTUNE'S DYNAMIC ATMOSPHERE FROM KEPLER K2 OBSERVATIONS: IMPLICATIONS FOR BROWN DWARF LIGHT CURVE ANALYSES.

    Simon, Amy A; Rowe, Jason F; Gaulme, Patrick; Hammel, Heidi B; Casewell, Sarah L; Fortney, Jonathan J; Gizis, John E; Lissauer, Jack J; Morales-Juberias, Raul; Orton, Glenn S; Wong, Michael H; Marley, Mark S

    2016-02-01

    Observations of Neptune with the Kepler Space Telescope yield a 49 day light curve with 98% coverage at a 1 minute cadence. A significant signature in the light curve comes from discrete cloud features. We compare results extracted from the light curve data with contemporaneous disk-resolved imaging of Neptune from the Keck 10-m telescope at 1.65 microns and Hubble Space Telescope visible imaging acquired nine months later. This direct comparison validates the feature latitudes assigned to the K2 light curve periods based on Neptune's zonal wind profile, and confirms observed cloud feature variability. Although Neptune's clouds vary in location and intensity on short and long timescales, a single large discrete storm seen in Keck imaging dominates the K2 and Hubble light curves; smaller or fainter clouds likely contribute to short-term brightness variability. The K2 Neptune light curve, in conjunction with our imaging data, provides context for the interpretation of current and future brown dwarf and extrasolar planet variability measurements. In particular we suggest that the balance between large, relatively stable, atmospheric features and smaller, more transient, clouds controls the character of substellar atmospheric variability. Atmospheres dominated by a few large spots may show inherently greater light curve stability than those which exhibit a greater number of smaller features.

  10. Gamma-Ray Light Curves from Pulsar Magnetospheres with Finite Conductivity

    Harding, A. K.; Kalapotharakos, C.; Kazanas, D.; Contopoulos, I.

    2012-01-01

    The Fermi Large Area Telescope has provided an unprecedented database for pulsar emission studies that includes gamma-ray light curves for over 100 pulsars. Modeling these light curves can reveal and constrain the geometry of the particle accelerator, as well as the pulsar magnetic field structure. We have constructed 3D magnetosphere models with finite conductivity, that bridge the extreme vacuum and force-free solutions used in previous light curves modeling. We are investigating the shapes of pulsar gamma-ray light curves using these dissipative solutions with two different approaches: (l) assuming geometric emission patterns of the slot gap and outer gap, and (2) using the parallel electric field provided by the resistive models to compute the trajectories and . emission of the radiating particles. The light curves using geometric emission patterns show a systematic increase in gamma-ray peak phase with increasing conductivity, introducing a new diagnostic of these solutions. The light curves using the model electric fields are very sensitive to the conductivity but do not resemble the observed Fermi light curves, suggesting that some screening of the parallel electric field, by pair cascades not included in the models, is necessary

  11. DETERMINATION OF THE LIGHT CURVE OF THE ARTIFICIAL SATELLITE BY ITS ROTATION PATH AS PREPARATION TO THE INVERSE PROBLEM SOLUTION

    Pavlenko, Daniil

    2012-01-01

    Developing the algorithm of estimation of the rotational parameters of the artificial satellite by its light curve, we face the necessity to compute test light curves for various initially given types of rotation and specific features of lighting of the satellite. In the present study the algorithm of creation of such light curves with the simulation method and the obtained result are described.

  12. TYPE Ia SUPERNOVA LIGHT-CURVE INFERENCE: HIERARCHICAL BAYESIAN ANALYSIS IN THE NEAR-INFRARED

    Mandel, Kaisey S.; Friedman, Andrew S.; Kirshner, Robert P.; Wood-Vasey, W. Michael

    2009-01-01

    We present a comprehensive statistical analysis of the properties of Type Ia supernova (SN Ia) light curves in the near-infrared using recent data from Peters Automated InfraRed Imaging TELescope and the literature. We construct a hierarchical Bayesian framework, incorporating several uncertainties including photometric error, peculiar velocities, dust extinction, and intrinsic variations, for principled and coherent statistical inference. SN Ia light-curve inferences are drawn from the global posterior probability of parameters describing both individual supernovae and the population conditioned on the entire SN Ia NIR data set. The logical structure of the hierarchical model is represented by a directed acyclic graph. Fully Bayesian analysis of the model and data is enabled by an efficient Markov Chain Monte Carlo algorithm exploiting the conditional probabilistic structure using Gibbs sampling. We apply this framework to the JHK s SN Ia light-curve data. A new light-curve model captures the observed J-band light-curve shape variations. The marginal intrinsic variances in peak absolute magnitudes are σ(M J ) = 0.17 ± 0.03, σ(M H ) = 0.11 ± 0.03, and σ(M Ks ) = 0.19 ± 0.04. We describe the first quantitative evidence for correlations between the NIR absolute magnitudes and J-band light-curve shapes, and demonstrate their utility for distance estimation. The average residual in the Hubble diagram for the training set SNe at cz > 2000kms -1 is 0.10 mag. The new application of bootstrap cross-validation to SN Ia light-curve inference tests the sensitivity of the statistical model fit to the finite sample and estimates the prediction error at 0.15 mag. These results demonstrate that SN Ia NIR light curves are as effective as corrected optical light curves, and, because they are less vulnerable to dust absorption, they have great potential as precise and accurate cosmological distance indicators.

  13. Characterization of Type Ia Supernova Light Curves Using Principal Component Analysis of Sparse Functional Data

    He, Shiyuan; Wang, Lifan; Huang, Jianhua Z.

    2018-04-01

    With growing data from ongoing and future supernova surveys, it is possible to empirically quantify the shapes of SNIa light curves in more detail, and to quantitatively relate the shape parameters with the intrinsic properties of SNIa. Building such relationships is critical in controlling systematic errors associated with supernova cosmology. Based on a collection of well-observed SNIa samples accumulated in the past years, we construct an empirical SNIa light curve model using a statistical method called the functional principal component analysis (FPCA) for sparse and irregularly sampled functional data. Using this method, the entire light curve of an SNIa is represented by a linear combination of principal component functions, and the SNIa is represented by a few numbers called “principal component scores.” These scores are used to establish relations between light curve shapes and physical quantities such as intrinsic color, interstellar dust reddening, spectral line strength, and spectral classes. These relations allow for descriptions of some critical physical quantities based purely on light curve shape parameters. Our study shows that some important spectral feature information is being encoded in the broad band light curves; for instance, we find that the light curve shapes are correlated with the velocity and velocity gradient of the Si II λ6355 line. This is important for supernova surveys (e.g., LSST and WFIRST). Moreover, the FPCA light curve model is used to construct the entire light curve shape, which in turn is used in a functional linear form to adjust intrinsic luminosity when fitting distance models.

  14. Light-Curve Diagnosis of a Hot Spot for Accretion-Disk Models

    FUKUE, Jun

    2003-01-01

    Light curves of a hot spot rotating in a relativistic Keplerian disk were found to be periodic with typically two peaks, originating from a gravitational focusing effect and a Doppler boost. On the other hand, we found that light curves of a hot spot spirally infalling in a sub-Keplerian advective disk are aperiodic with typically a single peak, originating from a gravitational focusing effect or a Doppler boost. Such a difference in the light curves of a hot spot can discriminate background ...

  15. New Light Curves and Analysis of the Overcontact Binaries PP Lac and DK Sge

    Sanders, S. J.; Hargis, J. R.; Bradstreet, D. H.

    2004-12-01

    As a by-product of the ongoing work with the Catalog and AtLas of Eclipsing Binaries database (CALEB; Bradstreet et al. 2004), several hundred eclipsing binary systems have been identified that have either unpublished or poor quality light curves. We present new V & Rc light curves for the overcontact systems PP Lac and DK Sge, both chosen because their deep eclipses (peak-to-peak amplitudes of nearly 0.7 mag) help constrain the light curve modelling. Data were obtained using the 41-cm telescope at the Eastern University Observatory equipped with an SBIG ST-10XME CCD. PP Lac (P= 0.40116 d) is a W-type contact binary with only one previously published light curve (Dumont & Maraziti 1990), but the data are sparse and almost non-existent at primary eclipse. Modelling of these data gave varying results; the published mass ratios differ by nearly 0.3. Our data confirms the noted differing eclipse depths but we find the primary eclipse to be total. We present a new light curve solution using Binary Maker 3 (Bradstreet & Steelman 2002) and Wilson-Devinney, finding the mass ratio to be well-constrained by the duration of total eclipse. A period study will be presented using previously existing and newly derived times of minimum light. DK Sge (P=0.62182 d) appears to be an A-type contact binary with no published light curve. The eclipses are partial, with the primary eclipse being deeper by about 0.08 mag. The maxima show evidence of a slight asymmetry, although the light curve appears to be repeatable over the 1 month of observations. We present the first light curve solution using Binary Maker 3 and Wilson-Devinney, but have limited mass ratio constraints due to the absence of radial velocity data. A period study will be presented using previously existing and newly derived times of minimum light.

  16. High precision, rapid laser hole drilling

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2013-04-02

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  17. Fourier analysis of the light curves of eclipsing variables. XI

    Kopal, Z.

    1977-01-01

    The aim of the present paper is to introduce a new definition of the loss of light suffered by mutual eclipses of the components of close binary systems: namely, as a cross-correlation of two apertures representing the eclipsing and eclipsed discs. The advantages of such a strategy over the more conventional (geometrical) approach are (a) greater symmetry of the respective expressions; (b) greater affinity of expressions arising from distortion with those expressing the light changes due to eclipses of spherical stars; and (c) greater freedom in dealing with the effects of particular distribution of brightness over the disc of the star undergoing eclipse (generalized limb-darkening), as well as of possible semi-transparency of the eclipsing component (Wolf-Rayet stars). In point of fact, none of these tasks could be handled with equal ease by any other technique; nor could the corresponding loss of light be so automated by any other approach. (Auth.)

  18. A method for the rapid generation of nonsequential light-response curves of chlorophyll fluorescence.

    Serôdio, João; Ezequiel, João; Frommlet, Jörg; Laviale, Martin; Lavaud, Johann

    2013-11-01

    Light-response curves (LCs) of chlorophyll fluorescence are widely used in plant physiology. Most commonly, LCs are generated sequentially, exposing the same sample to a sequence of distinct actinic light intensities. These measurements are not independent, as the response to each new light level is affected by the light exposure history experienced during previous steps of the LC, an issue particularly relevant in the case of the popular rapid light curves. In this work, we demonstrate the proof of concept of a new method for the rapid generation of LCs from nonsequential, temporally independent fluorescence measurements. The method is based on the combined use of sample illumination with digitally controlled, spatially separated beams of actinic light and a fluorescence imaging system. It allows the generation of a whole LC, including a large number of actinic light steps and adequate replication, within the time required for a single measurement (and therefore named "single-pulse light curve"). This method is illustrated for the generation of LCs of photosystem II quantum yield, relative electron transport rate, and nonphotochemical quenching on intact plant leaves exhibiting distinct light responses. This approach makes it also possible to easily characterize the integrated dynamic light response of a sample by combining the measurement of LCs (actinic light intensity is varied while measuring time is fixed) with induction/relaxation kinetics (actinic light intensity is fixed and the response is followed over time), describing both how the response to light varies with time and how the response kinetics varies with light intensity.

  19. Light curves for ''bump Cepheids'' computed with a dynamically zoned pulsation code

    Adams, T.F.; Castor, J.E.; Davis, C.G.

    1978-01-01

    The dynamically zoned pulsation code developed by Castor, Davis, and Davison has been used to recalculate the Goddard model and to calculate three other Cepheid models with the same period (9.8 days). This family of models shows how the bumps and other features of the light and velocity curves change as the mass is varied at constant period. This study, with a code that is capable of producing reliable light curves, shows again that the light and velocity curves for 9.8-day Cepheid models with standard homogeneous compositions do not show bumps like those that are observed unless the mass is significantly lower than the ''evolutionary mass.'' The light and velocity curves for the Goddard model presented here are similar to those computed independently by Fischel, Sparks, and Karp. They should be useful as standards for future investigators

  20. Eclipsing binary stars with extreme light curve asymmetries mined from large astronomical surveys

    Papageorgiou Athanasios

    2017-01-01

    Full Text Available The O’Connell effect is one of the most perplexing challenges in binary studies as it has not been convincingly explained. Furthermore, a simple method to obtain essential parameters for eclipsing binaries exhibiting this effect and to extract information describing the asymmetry in the light curve maxima is needed. We have developed an automated program that characterizes the morphology of light curves by depth of both minima, height of both maxima and curvature outside the eclipses.

  1. High-Precision Computation and Mathematical Physics

    Bailey, David H.; Borwein, Jonathan M.

    2008-01-01

    At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion effort. This paper presents a survey of recent applications of these techniques and provides some analysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, scattering amplitudes of quarks, gluons and bosons, nonlinear oscillator theory, Ising theory, quantum field theory and experimental mathematics. We conclude that high-precision arithmetic facilities are now an indispensable component of a modern large-scale scientific computing environment.

  2. REFLECTED LIGHT CURVES, SPHERICAL AND BOND ALBEDOS OF JUPITER- AND SATURN-LIKE EXOPLANETS

    Dyudina, Ulyana; Kopparla, Pushkar; Ingersoll, Andrew P.; Yung, Yuk L. [Division of Geological and Planetary Sciences, 150-21 California Institute of Technology, Pasadena, CA 91125 (United States); Zhang, Xi [University of California Santa Cruz 1156 High Street, Santa Cruz, CA 95064 (United States); Li, Liming [Department of Physics, University of Houston, Houston, TX 77204 (United States); Dones, Luke [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder CO 80302 (United States); Verbiscer, Anne, E-mail: ulyana@gps.caltech.edu [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)

    2016-05-10

    Reflected light curves observed for exoplanets indicate that a few of them host bright clouds. We estimate how the light curve and total stellar heating of a planet depends on forward and backward scattering in the clouds based on Pioneer and Cassini spacecraft images of Jupiter and Saturn. We fit analytical functions to the local reflected brightnesses of Jupiter and Saturn depending on the planet’s phase. These observations cover broadbands at 0.59–0.72 and 0.39–0.5 μ m, and narrowbands at 0.938 (atmospheric window), 0.889 (CH4 absorption band), and 0.24–0.28 μ m. We simulate the images of the planets with a ray-tracing model, and disk-integrate them to produce the full-orbit light curves. For Jupiter, we also fit the modeled light curves to the observed full-disk brightness. We derive spherical albedos for Jupiter and Saturn, and for planets with Lambertian and Rayleigh-scattering atmospheres. Jupiter-like atmospheres can produce light curves that are a factor of two fainter at half-phase than the Lambertian planet, given the same geometric albedo at transit. The spherical albedo is typically lower than for a Lambertian planet by up to a factor of ∼1.5. The Lambertian assumption will underestimate the absorption of the stellar light and the equilibrium temperature of the planetary atmosphere. We also compare our light curves with the light curves of solid bodies: the moons Enceladus and Callisto. Their strong backscattering peak within a few degrees of opposition (secondary eclipse) can lead to an even stronger underestimate of the stellar heating.

  3. Searching for transits in the Wide Field Camera Transit Survey with difference-imaging light curves

    Zendejas, Dominguez J.; Koppenhoefer, J.; Saglia, R.; Birkby, J.L.; Hodgkin, S.; Kovács, G.; Pinfield, D.; Sipocz, B.; Barrado, D.; Bender, R.; Burgo, del C.; Cappetta, M.; Martín, E.; Nefs, B.; Riffeser, A.; Steele, P.

    2013-01-01

    The Wide Field Camera Transit Survey is a pioneer program aiming at for searching extra-solar planets in the near-infrared. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. We produce an alternative set of light

  4. X-ray heating and the optical light curve of HZ Herculis

    Perrenod, S.C.; Shields, G.A.

    1975-01-01

    We discuss theoretically the optical light curve of HZ Her, the binary companion of the pulsed X-ray source Her X-1. Using model stellar atmospheres, we construct light curves that are in agreement with UBV photometry of HZ Her except for the sharpness of the minimum. Unlike previous authors, we find that heating of the photosphere of HZ Her by the observed X-ray flux is sufficient to explain the amplitude of the light variations in each color, if the X-ray emission persists at HZ Her throughout the 35-day ON-OFF CYCLE. We rule out a corona surrounding HZ Her as the source of the extra light near minimum, and we also rule out a model wherein the extra light is caused by a stellar wind that electron-scatters optical light emitted by the photosphere of the hot side of the star

  5. Gamma-Ray Pulsar Light Curves as Probes of Magnetospheric Structure

    Harding, A. K.

    2016-01-01

    The large number of gamma-ray pulsars discovered by the Fermi Gamma-Ray Space Telescope since its launch in 2008 dwarfs the handful that were previously known. The variety of observed light curves makes possible a tomography of both the ensemble-averaged field structure and the high-energy emission regions of a pulsar magnetosphere. Fitting the gamma-ray pulsar light curves with model magnetospheres and emission models has revealed that most of the high-energy emission, and the particles acceleration, takes place near or beyond the light cylinder, near the current sheet. As pulsar magnetosphere models become more sophisticated, it is possible to probe magnetic field structure and emission that are self-consistently determined. Light curve modeling will continue to be a powerful tool for constraining the pulsar magnetosphere physics.

  6. High precision detector robot arm system

    Shu, Deming; Chu, Yong

    2017-01-31

    A method and high precision robot arm system are provided, for example, for X-ray nanodiffraction with an X-ray nanoprobe. The robot arm system includes duo-vertical-stages and a kinematic linkage system. A two-dimensional (2D) vertical plane ultra-precision robot arm supporting an X-ray detector provides positioning and manipulating of the X-ray detector. A vertical support for the 2D vertical plane robot arm includes spaced apart rails respectively engaging a first bearing structure and a second bearing structure carried by the 2D vertical plane robot arm.

  7. Automatic titrator for high precision plutonium assay

    Jackson, D.D.; Hollen, R.M.

    1986-01-01

    Highly precise assay of plutonium metal is required for accountability measurements. We have developed an automatic titrator for this determination which eliminates analyst bias and requires much less analyst time. The analyst is only required to enter sample data and start the titration. The automated instrument titrates the sample, locates the end point, and outputs the results as a paper tape printout. Precision of the titration is less than 0.03% relative standard deviation for a single determination at the 250-mg plutonium level. The titration time is less than 5 min

  8. Recent high precision surveys at PEP

    Sah, R.C.

    1980-12-01

    The task of surveying and aligning the components of PEP has provided an opportunity to develop new instruments and techniques for the purpose of high precision surveys. The new instruments are quick and easy to use, and they automatically encode survey data and read them into the memory of an on-line computer. When measurements of several beam elements have been taken, the on-line computer analyzes the measured data, compares them with desired parameters, and calculates the required adjustments to beam element support stands

  9. Timescale stretch parameterization of Type Ia supernova B-band light curves

    Goldhaber, G.; Groom, D.E.; Kim, A.; Aldering, G.; Astier, P.; Conley, A.; Deustua, S.E.; Ellis, R.; Fabbro, S.; Fruchter, A.S.; Goobar, A.; Hook, I.; Irwin, M.; Kim, M.; Knop, R.A.; Lidman, C.; McMahon, R.; Nugent, P.E.; Pain, R.; Panagia, N.; Pennypacker, C.R.; Perlmutter, S.; Ruiz-Lapuente, P.; Schaefer, B.; Walton, N.A.; York, T.

    2001-01-01

    R-band intensity measurements along the light curve of Type Ia supernovae discovered by the Cosmology Project (SCP) are fitted in brightness to templates allowing a free parameter the time-axis width factor w identically equal to s times (1+z). The data points are then individually aligned in the time-axis, normalized and K-corrected back to the rest frame, after which the nearly 1300 normalized intensity measurements are found to lie on a well-determined common rest-frame B-band curve which we call the ''composite curve.'' The same procedure is applied to 18 low-redshift Calan/Tololo SNe with Z < 0.11; these nearly 300 B-band photometry points are found to lie on the composite curve equally well. The SCP search technique produces several measurements before maximum light for each supernova. We demonstrate that the linear stretch factor, s, which parameterizes the light-curve timescale appears independent of z, and applies equally well to the declining and rising parts of the light curve. In fact, the B band template that best fits this composite curve fits the individual supernova photometry data when stretched by a factor s with chi 2/DoF ∼ 1, thus as well as any parameterization can, given the current data sets. The measurement of the data of explosion, however, is model dependent and not tightly constrained by the current data. We also demonstrate the 1 + z light-cure time-axis broadening expected from cosmological expansion. This argues strongly against alternative explanations, such as tired light, for the redshift of distant objects

  10. KEPLER ECLIPSING BINARY STARS. III. CLASSIFICATION OF KEPLER ECLIPSING BINARY LIGHT CURVES WITH LOCALLY LINEAR EMBEDDING

    Matijevič, Gal; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Bloemen, Steven; Barclay, Thomas

    2012-01-01

    We present an automated classification of 2165 Kepler eclipsing binary (EB) light curves that accompanied the second Kepler data release. The light curves are classified using locally linear embedding, a general nonlinear dimensionality reduction tool, into morphology types (detached, semi-detached, overcontact, ellipsoidal). The method, related to a more widely used principal component analysis, produces a lower-dimensional representation of the input data while preserving local geometry and, consequently, the similarity between neighboring data points. We use this property to reduce the dimensionality in a series of steps to a one-dimensional manifold and classify light curves with a single parameter that is a measure of 'detachedness' of the system. This fully automated classification correlates well with the manual determination of morphology from the data release, and also efficiently highlights any misclassified objects. Once a lower-dimensional projection space is defined, the classification of additional light curves runs in a negligible time and the method can therefore be used as a fully automated classifier in pipeline structures. The classifier forms a tier of the Kepler EB pipeline that pre-processes light curves for the artificial intelligence based parameter estimator.

  11. Human phase response curve to a 1 h pulse of bright white light

    St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

    2012-01-01

    The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n= 18) or dim background light (n= 18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting. PMID:22547633

  12. A Composite Light Curve Model of the Symbiotic Nova PU Vul (1979

    Kato M.

    2012-06-01

    Full Text Available PU Vul (1979 is a symbiotic nova that shows a long-lasting flat optical peak followed by a slow decline. We made a quasi-evolution model for outbursts on a 0.6 M⊙ white dwarf consisting of a series of static solutions with optically-thin winds. Our theoretical models reproduce well the observed visual/UV light curves as well as the new estimates of the temperature and radius of the hot component. We also modeled the light curve of the 1980 and 1994 eclipses as the total eclipse occulted by a pulsating M-giant companion star. In the second eclipse, the visual magnitude is dominated by nebular emission which is possibly ejected from the hot component between 1990 to 2000. We have quantitatively estimated three components of emission, i.e., the white dwarf, companion and nebular, and made a composite light curve that represents well the evolution of the PU Vul outburst.

  13. Light Curve Simulation Using Spacecraft CAD Models and Empirical Material Spectral BRDFS

    Willison, A.; Bedard, D.

    This paper presents a Matlab-based light curve simulation software package that uses computer-aided design (CAD) models of spacecraft and the spectral bidirectional reflectance distribution function (sBRDF) of their homogenous surface materials. It represents the overall optical reflectance of objects as a sBRDF, a spectrometric quantity, obtainable during an optical ground truth experiment. The broadband bidirectional reflectance distribution function (BRDF), the basis of a broadband light curve, is produced by integrating the sBRDF over the optical wavelength range. Colour-filtered BRDFs, the basis of colour-filtered light curves, are produced by first multiplying the sBRDF by colour filters, and integrating the products. The software package's validity is established through comparison of simulated reflectance spectra and broadband light curves with those measured of the CanX-1 Engineering Model (EM) nanosatellite, collected during an optical ground truth experiment. It is currently being extended to simulate light curves of spacecraft in Earth orbit, using spacecraft Two-Line-Element (TLE) sets, yaw/pitch/roll angles, and observer coordinates. Measured light curves of the NEOSSat spacecraft will be used to validate simulated quantities. The sBRDF was chosen to represent material reflectance as it is spectrometric and a function of illumination and observation geometry. Homogeneous material sBRDFs were obtained using a goniospectrometer for a range of illumination and observation geometries, collected in a controlled environment. The materials analyzed include aluminum alloy, two types of triple-junction photovoltaic (TJPV) cell, white paint, and multi-layer insulation (MLI). Interpolation and extrapolation methods were used to determine the sBRDF for all possible illumination and observation geometries not measured in the laboratory, resulting in empirical look-up tables. These look-up tables are referenced when calculating the overall sBRDF of objects, where

  14. Light curve analysis of the late type binary V523 Cassiopeiae

    Latković O.

    2009-01-01

    Full Text Available We present the analysis of V and R light curves of the late type contact binary V523 Cas for the season of 2006. These observations make part of the monitoring program aimed at studying the long-term light curve variability in this system. Our results confirm that the system is in an over contact configuration, and include a bright spot in the neck region of the cooler and larger primary. We compare these results with the previous solution, obtained for the season 2005 dataset and discuss the differences.

  15. Digitalization of highly precise fluxgate magnetometers

    Cerman, Ales; Kuna, A.; Ripka, P.

    2005-01-01

    This paper describes the theory behind all three known ways of digitalizing the fluxgate magnetometers: analogue magnetometers with digitalized output using high resolution ADC, application of the delta-sigma modulation to the sensor feedback loop and fully digital signal detection. At present time...... the Delta-Sigma ADCs are mostly used for the digitalization of the highly precise fluxgate magnetorneters. The relevant part of the paper demonstrates some pitfalls of their application studied during the design of the magnetometer for the new Czech scientific satellite MIMOSA. The part discussing...... the application of the A-E modulation to the sensor feedback loop theoretically derives the main advantage of this method-increasing of the modulation order and shows its real potential compared to the analog magnetometer with consequential digitalization. The comparison is realized on the modular magnetometer...

  16. Using Light Curves to Characterize Size and Shape of Pseudo-Debris

    Rodriquez, Heather M.; Abercromby, Kira J.; Jarvis, Kandy S.; Barker, Edwin

    2006-01-01

    Photometric measurements were collected for a new study aimed at estimating orbital debris sizes based on object brightness. To obtain a size from optical measurements the current practice is to assume an albedo and use a normalized magnitude to calculate optical size. However, assuming a single albedo value may not be valid for all objects or orbit types; material type and orientation can mask an object s true optical cross section. This experiment used a CCD camera to record data, a 300 W Xenon, Ozone Free collimated light source to simulate solar illumination, and a robotic arm with five degrees of freedom to move the piece of simulated debris through various orientations. The pseudo-debris pieces used in this experiment originate from the European Space Operations Centre s ESOC2 ground test explosion of a mock satellite. A uniformly illuminated white ping-pong ball was used as a zero-magnitude reference. Each debris piece was then moved through specific orientations and rotations to generate a light curve. This paper discusses the results of five different object-based light curves as measured through an x-rotation. Intensity measurements, from which each light curve was generated, were recorded in five degree increments from zero to 180 degrees. Comparing light curves of different shaped and sized pieces against their characteristic length establishes the start of a database from which an optical size estimation model will be derived in the future.

  17. High precision neutron polarization for PERC

    Klauser, C.

    2013-01-01

    The decay of the free neutron into a proton, an electron and an anti-electron neutrino offers a simple system to study the semi-leptonic weak decay. High precision measurements of angular correlation coefficients of this decay provide the opportunity to test the standard model on the low energy frontier. The Proton Electron Radiation Channel PERC is part of a new generation of expriments pushing the accuracy of such an angular correlation coefficient measurement towards 10 -4 . Past experiments have been limited to an accuracy of 10 -3 with uncertainties on the neutron polarization as one of the leading systematic errors. This thesis focuses on the development of a stable, highly precise neutron polarization for a large, divergent cold neutron beam. A diagnostic tool that provides polarization higher than 99.99 % and analyzes with an accuracy of 10 -4 , the Opaque Test Bench, is presented and validated. It consists of two highly opaque polarized helium cells. The Opaque Test Bench reveals depolarizing effects in polarizing supermirrors commonly used for polarization in neutron decay experiments. These effects are investigated in detail. They are due to imperfect lateral magnetization in supermirror layers and can be minimized by significantly increased magnetizing fields and low incidence angle and supermirror factor m. A subsequent test in the crossed (X-SM) geometry demonstrated polarizations up to 99.97% from supermirrors only, improving neutron polarization with supermirrors by an order of magnitude. The thesis also discusses other neutron optical components of the PERC beamline: Monte-Carlo simulations of the beamline under consideration of the primary guide are carried out. In addition, calculation shows that PERC would statistically profit from an installation at the European Spallation source. Furthermore, beamline components were tested. A radio-frequency spin flipper was confirmed to work with an efficiency higher than 0.9999. (author) [de

  18. LATE-TIME LIGHT CURVES OF TYPE II SUPERNOVAE: PHYSICAL PROPERTIES OF SUPERNOVAE AND THEIR ENVIRONMENT

    Otsuka, Masaaki; Meixner, Margaret; Panagia, Nino [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Fabbri, Joanna; Barlow, Michael J.; Wesson, Roger [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Clayton, Geoffrey C.; Andrews, Jennifer E. [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States); Gallagher, Joseph S. [Department of Mathematics, Physics, and Computer Science, Raymond Walters College, 9555 Plain field Rd., Blue Ash, OH 45236 (United States); Sugerman, Ben E. K. [Department of Physics and Astronomy, Goucher College, 1021 Dulaney Valley Road, Baltimore, MD 21204 (United States); Ercolano, Barbara [Universitaets-Sternwarte Muenchen, Scheinerstr. 1, 81679 Muenchen (Germany); Welch, Douglas, E-mail: otsuka@stsci.edu, E-mail: otsuka@asiaa.sinica.edu.tw [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)

    2012-01-01

    We present BVRIJHK-band photometry of six core-collapse supernovae, SNe 1999bw, 2002hh, 2003gd, 2004et, 2005cs, and 2006bc, measured at late epochs (>2 yr) based on the Hubble Space Telescope (HST), and the Gemini North, and WIYN telescopes. We also show the JHK light curves of supernova impostor SN 2008S up to day 575 because it was serendipitously in our SN 2002hh field of view. Of our 43 HST observations in total, 36 observations are successful in detecting the light from the SNe alone and measuring magnitudes of all the targets. HST observations show a resolved scattered light echo around SN 2003gd at day 1520 and around SN 2002hh at day 1717. Our Gemini and WIYN observations detected SNe 2002hh and 2004et as well. Combining our data with previously published data, we show VRIJHK-band light curves and estimate decline magnitude rates at each band in four different phases. Our prior work on these light curves and other data indicate that dust is forming in our targets from days {approx}300 to 400, supporting SN dust formation theory. In this paper we focus on other physical properties derived from late-time light curves. We estimate {sup 56}Ni masses for our targets (0.5-14 Multiplication-Sign 10{sup -2} M{sub Sun }) from the bolometric light curve of each of days {approx}150-300 using SN 1987A as a standard (7.5 Multiplication-Sign 10{sup -2} M{sub Sun }). The flattening or sometimes increasing fluxes in the late-time light curves of SNe 2002hh, 2003gd, 2004et, and 2006bc indicate the presence of light echoes. We estimate the circumstellar hydrogen density of the material causing the light echo and find that SN 2002hh is surrounded by relatively dense materials (n(H) >400 cm{sup -3}) and SNe 2003gd and 2004et have densities more typical of the interstellar medium ({approx}1 cm{sup -3}). We analyze the sample as a whole in the context of physical properties derived in prior work. The {sup 56}Ni mass appears well correlated with progenitor mass with a slope of 0

  19. SHOCK BREAKOUT AND EARLY LIGHT CURVES OF TYPE II-P SUPERNOVAE OBSERVED WITH KEPLER

    Garnavich, P. M.; Tucker, B. E.; Rest, A.; Shaya, E. J.; Olling, R. P.; Kasen, D; Villar, A.

    2016-01-01

    We discovered two transient events in the Kepler field with light curves that strongly suggest they are type II-P supernovae (SNe II-P). Using the fast cadence of the Kepler observations we precisely estimate the rise time to maximum for KSN2011a and KSN2011d as 10.5 ± 0.4 and 13.3 ± 0.4 rest-frame days, respectively. Based on fits to idealized analytic models, we find the progenitor radius of KSN2011a (280 ± 20 R ⊙ ) to be significantly smaller than that for KSN2011d (490 ± 20 R ⊙ ), but both have similar explosion energies of 2.0 ± 0.3 × 10 51 erg. The rising light curve of KSN2011d is an excellent match to that predicted by simple models of exploding red supergiants (RSG). However, the early rise of KSN2011a is faster than the models predict, possibly due to the supernova shock wave moving into pre-existing wind or mass-loss from the RSG. A mass-loss rate of 10 −4 M ⊙ yr −1 from the RSG can explain the fast rise without impacting the optical flux at maximum light or the shape of the post-maximum light curve. No shock breakout emission is seen in KSN2011a, but this is likely due to the circumstellar interaction suspected in the fast rising light curve. The early light curve of KSN2011d does show excess emission consistent with model predictions of a shock breakout. This is the first optical detection of a shock breakout from a SNe II-P

  20. Light Curve Stability and Period Behavior of the Contact Binary TZ ...

    J. Astrophys. Astr. (2013) 34, 329–339 c Indian Academy of Sciences. Light Curve Stability and Period Behavior of the Contact. Binary TZ Boo. M. M. Elkhateeb1,2 & M. I. Nouh1,2,∗. 1National Research Institute of Astronomy and Geophysics, 11421 Helwan, Cairo, Egypt. 2Physics Department, College of Science, Northern ...

  1. New methods for deriving cometary secular light curves: C/1995 O1 (Hale-Bopp) revisited

    Womack, Maria; Lastra, Nathan; Harrington, Olga; Curtis, Anthony; Wierzchos, Kacper; Ruffini, Nicholas; Charles, Mentzer; Rabson, David; Cox, Timothy; Rivera, Isabel; Micciche, Anthony

    2017-10-01

    We present an algorithm for reducing scatter and increasing precision in a comet light curve. As a demonstration, we processed apparent magnitudes of comet Hale-Bopp from 16 highly experienced observers (archived with the International Comet Quarterly), correcting for distance from Earth and phase angle. Different observers tend to agree on the difference in magnitudes of an object at different distances, but the magnitude reported by observer is shifted relative to that of another for an object at a fixed distance. We estimated the shifts using a self-consistent statistical approach, leading to a sharper light curve and improving the precision of the measured slopes. The final secular lightcurve for comet Hale-Bopp ranges from -7 au (pre-perihelion) to +8 au (post-perihelion) and is the best secular light curve produced to date for this “great” comet. We discuss Hale-Bopp’s lightcurve evolution and possibly related physical implications, and potential usefulness of this light curve for comparisons with other future bright comets. We also assess the appropriateness of using secular lightcurves to characterize dust production rates in Hale-Bopp and other dust-rich comets. M.W. acknowledges support from NSF grant AST-1615917.

  2. EXPLORING THE POTENTIAL DIVERSITY OF EARLY TYPE IA SUPERNOVA LIGHT CURVES

    Piro, Anthony L. [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Morozova, Viktoriya S., E-mail: piro@obs.carnegiescience.edu [Theoretical Astrophysics, California Institute of Technology, 1200 E California Boulevard, M/C 350-17, Pasadena, CA 91125 (United States)

    2016-07-20

    During the first several days after explosion, Type Ia supernova light curves probe the outer layers of the exploding star, and therefore provide important clues for identifying their progenitors. We investigate how both the shallow {sup 56}Ni distribution and the presence of circumstellar material shape these early light curves. This is performed using a series of numerical experiments with parameterized properties for systematic exploration. Although not all of the considered models may be realized in nature (and indeed there are arguments why some of them should not occur), the spirit of this work is to provide a broader exploration of the diversity of possibilities. We find that shallower {sup 56}Ni leads to steeper, bluer light curves. Differences in the shape of the rise can introduce errors in estimating the explosion time, and thus impact efforts to infer upper limits on the progenitor or companion radius from a lack of observed shock cooling emission. Circumstellar material can lead to significant luminosity during the first few days, but its presence can be difficult to identify depending on the degree of nickel mixing. In some cases, the hot emission of circumstellar material may even lead to a signature similar to an interaction with a companion, and thus in the future additional diagnostics should be gathered for properly assessing early light curves.

  3. Fractal Property in the Light Curve of BL Lac Object S5 0716+714

    2016-01-27

    Jan 27, 2016 ... In this paper, we compile the historical R-band data of S5 0716+714 from literature and obtain its fractal dimension by using a fractal method and then simulate the data with the Weierstrass–Mandelbrot (W–M) function. It is considered that the light curve has a fractal property.

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

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

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

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

  6. Characterizing the V-band light-curves of hydrogen-rich type II supernovae

    Anderson, Joseph P.; González-Gaitán, Santiago; Hamuy, Mario

    2014-01-01

    a dispersion of 0.56 mag, offering the prospect of using type II supernovae as purely photometric distance indicators. Our analysis suggests that the type II population spans a continuum from low-luminosity events which have flat light-curves during the "plateau" stage, through to the brightest events which...

  7. Photometric light curves for ten rapidly rotating stars in Alpha Persei, the Pleiades, and the field

    Prosser, Charles F.; Schild, Rudolph E.; Stauffer, John R.; Jones, Burton F.

    1993-01-01

    We present the results from a photometric monitoring program of ten rapidly rotating stars observed during 1991 using the FLWO 48-in. telescope. Brightness variations for an additional six cluster stars observed with the Lick 40-in. telescope are also given. The periods and light curves for seven Alpha Persei members, two Pleiades members, and one naked T Tauri field star are reported.

  8. UBV Light Curves of AR Lacertae During 1980-'81 and 1981-'82

    Il-Seong Nha

    1985-12-01

    Full Text Available The UBV observations of the brightest RE CVn-type eclipsing binary star AR Lac were made at four observatories, two in Korea and two in the U.S. in the 1980-81 and 1981-82 seasons. As a result of the cooperation, two light curves in the yellow and in the blue were completed for each observing seasons. Ultraviolet observations were also made at three of the four observatories. The orbital period of AR Lac apparantly decreased around 1977. An analysis of our yellow light curves together with five other yellow curves available in the literature since 1975 shows that there seems no periodicity in the migration of the distortion waves. There is a gradual decrease of at least 0.m1 between 1976 and 1982 in the brightness of the cooler component if one assumes that the hotter component is constant.

  9. Exquisite Nova Light Curves from the Solar Mass Ejection Imager (SMEI)

    Hounsell, R.; Bode, M. F.; Hick, P. P.; Buffington, A.; Jackson, B. V.; Clover, J. M.; Shafter, A. W.; Darnley, M. J.; Mawson, N. R.; Steele, I. A.; Evans, A.; Eyres, S. P. S.; O'Brien, T. J.

    2010-11-01

    We present light curves of three classical novae (CNe; KT Eridani, V598 Puppis, V1280 Scorpii) and one recurrent nova (RS Ophiuchi) derived from data obtained by the Solar Mass Ejection Imager (SMEI) on board the Coriolis satellite. SMEI provides near complete skymap coverage with precision visible-light photometry at 102 minute cadence. The light curves derived from these skymaps offer unprecedented temporal resolution around, and especially before, maximum light, a phase of the eruption normally not covered by ground-based observations. They allow us to explore fundamental parameters of individual objects including the epoch of the initial explosion, the reality and duration of any pre-maximum halt (found in all three fast novae in our sample), the presence of secondary maxima, speed of decline of the initial light curve, plus precise timing of the onset of dust formation (in V1280 Sco) leading to estimation of the bolometric luminosity, white dwarf mass, and object distance. For KT Eri, Liverpool Telescope SkyCamT data confirm important features of the SMEI light curve and overall our results add weight to the proposed similarities of this object to recurrent rather than to CNe. In RS Oph, comparison with hard X-ray data from the 2006 outburst implies that the onset of the outburst coincides with extensive high-velocity mass loss. It is also noted that two of the four novae we have detected (V598 Pup and KT Eri) were only discovered by ground-based observers weeks or months after maximum light, yet these novae reached peak magnitudes of 3.46 and 5.42, respectively. This emphasizes the fact that many bright novae per year are still overlooked, particularly those of the very fast speed class. Coupled with its ability to observe novae in detail even when relatively close to the Sun in the sky, we estimate that as many as five novae per year may be detectable by SMEI.

  10. EXPLORING THE VARIABLE SKY WITH LINEAR. III. CLASSIFICATION OF PERIODIC LIGHT CURVES

    Palaversa, Lovro; Eyer, Laurent; Rimoldini, Lorenzo [Observatoire Astronomique de l' Université de Genève, 51 chemin des Maillettes, CH-1290 Sauverny (Switzerland); Ivezić, Željko; Loebman, Sarah; Hunt-Walker, Nicholas; VanderPlas, Jacob; Westman, David; Becker, Andrew C. [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195-1580 (United States); Ruždjak, Domagoj; Sudar, Davor; Božić, Hrvoje [Hvar Observatory, Faculty of Geodesy, Kačićeva 26, 10000 Zagreb (Croatia); Galin, Mario [Faculty of Geodesy, Kačićeva 26, 10000 Zagreb (Croatia); Kroflin, Andrea; Mesarić, Martina; Munk, Petra; Vrbanec, Dijana [Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, 10000 Zagreb (Croatia); Sesar, Branimir [Division of Physics, Mathematics, and Astronomy, Caltech, Pasadena, CA 91125 (United States); Stuart, J. Scott [Lincoln Laboratory, Massachusetts Institute of Technology, 244 Wood Street, Lexington, MA 02420-9108 (United States); Srdoč, Gregor, E-mail: lovro.palaversa@unige.ch [Saršoni 90, 51216 Viškovo (Croatia); and others

    2013-10-01

    We describe the construction of a highly reliable sample of ∼7000 optically faint periodic variable stars with light curves obtained by the asteroid survey LINEAR across 10,000 deg{sup 2} of the northern sky. The majority of these variables have not been cataloged yet. The sample flux limit is several magnitudes fainter than most other wide-angle surveys; the photometric errors range from ∼0.03 mag at r = 15 to ∼0.20 mag at r = 18. Light curves include on average 250 data points, collected over about a decade. Using Sloan Digital Sky Survey (SDSS) based photometric recalibration of the LINEAR data for about 25 million objects, we selected ∼200,000 most probable candidate variables with r < 17 and visually confirmed and classified ∼7000 periodic variables using phased light curves. The reliability and uniformity of visual classification across eight human classifiers was calibrated and tested using a catalog of variable stars from the SDSS Stripe 82 region and verified using an unsupervised machine learning approach. The resulting sample of periodic LINEAR variables is dominated by 3900 RR Lyrae stars and 2700 eclipsing binary stars of all subtypes and includes small fractions of relatively rare populations such as asymptotic giant branch stars and SX Phoenicis stars. We discuss the distribution of these mostly uncataloged variables in various diagrams constructed with optical-to-infrared SDSS, Two Micron All Sky Survey, and Wide-field Infrared Survey Explorer photometry, and with LINEAR light-curve features. We find that the combination of light-curve features and colors enables classification schemes much more powerful than when colors or light curves are each used separately. An interesting side result is a robust and precise quantitative description of a strong correlation between the light-curve period and color/spectral type for close and contact eclipsing binary stars (β Lyrae and W UMa): as the color-based spectral type varies from K4 to F5, the

  11. The Discovery of Ellipsoidal Variations in the Kepler Light Curve of HAT-P-7

    Welsh, William F.; Orosz, Jerome A.; Seager, Sara; Fortney, Jonathan J.; Jenkins, Jon; Rowe, Jason F.; Koch, David; Borucki, William J.

    2010-01-01

    We present an analysis of the early Kepler observations of the previously discovered transiting planet HAT-P-7b. The light curve shows the transit of the star, the occultation of the planet, and the orbit phase-dependent light from the planet. In addition, phase-dependent light from the star is present, known as "ellipsoidal variations". The very nearby planet (only 4 stellar radii away) gravitationally distorts the star and results in a flux modulation twice per orbit. The ellipsoidal variat...

  12. SUPERLUMINOUS SUPERNOVAE POWERED BY MAGNETARS: LATE-TIME LIGHT CURVES AND HARD EMISSION LEAKAGE

    Wang, S. Q.; Wang, L. J.; Dai, Z. G.; Wu, X. F.

    2015-01-01

    Recently, research performed by two groups has revealed that the magnetar spin-down energy injection model with full energy trapping can explain the early-time light curves of SN 2010gx, SN 2013dg, LSQ12dlf, SSS120810, and CSS121015 but fails to fit the late-time light curves of these superluminous supernovae (SLSNe). These results imply that the original magnetar-powered model is challenged in explaining these SLSNe. Our paper aims to simultaneously explain both the early- and late-time data/upper limits by considering the leakage of hard emissions. We incorporate quantitatively the leakage effect into the original magnetar-powered model and derive a new semianalytical equation. Comparing the light curves reproduced by our revised magnetar-powered model with the observed data and/or upper limits of these five SLSNe, we found that the late-time light curves reproduced by our semianalytical equation are in good agreement with the late-time observed data and/or upper limits of SN 2010gx, CSS121015, SN 2013dg, and LSQ12dlf and the late-time excess of SSS120810, indicating that the magnetar-powered model might be responsible for these SLSNe and that the gamma-ray and X-ray leakages are unavoidable when the hard photons were down-Comptonized to softer photons. To determine the details of the leakage effect and unveil the nature of SLSNe, more high-quality bolometric light curves and spectra of SLSNe are required

  13. The effect of lunarlike satellites on the orbital infrared light curves of Earth-analog planets.

    Moskovitz, Nicholas A; Gaidos, Eric; Williams, Darren M

    2009-04-01

    We have investigated the influence of lunarlike satellites on the infrared orbital light curves of Earth-analog extrasolar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet and determine its orbit. We used an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon, and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of Earth, while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g., via spectroscopy or visible-wavelength detection of specular glint from a surface ocean), only the largest (approximately Mars-sized) lunarlike satellites can be detected by light curve data from a TPF-like instrument (i.e., one that achieves a photometric signal-to-noise ratio of 10 to 20 at infrared wavelengths). Nondetection of a lunarlike satellite can obfuscate the interpretation of a given system's infrared light curve so that it may resemble a single planet with high obliquity, different orbital longitude of vernal equinox relative to inferior conjunction, and in some cases drastically different thermal characteristics. If the thermal properties of the planet are not independently established, then the presence of a lunarlike satellite cannot be inferred from infrared data, which would thus demonstrate that photometric light curves alone can only be used for preliminary study, and the addition of spectroscopic data will be necessary.

  14. The Peculiar Light Curve of J1415+1320: A Case Study in Extreme Scattering Events

    Vedantham, H. K.; Readhead, A. C. S.; Hovatta, T.; Koopmans, L. V. E.; Pearson, T. J.; Blandford, R. D.; Gurwell, M. A.; Lähteenmäki, A.; Max-Moerbeck, W.; Pavlidou, V.; Ravi, V.; Reeves, R. A.; Richards, J. L.; Tornikoski, M.; Zensus, J. A.

    2017-08-01

    The radio light curve of J1415+1320 (PKS 1413+135) shows time-symmetric and recurring U-shaped features across the centimeter-wave and millimeter-wave bands. The symmetry of these features points to lensing by an intervening object as the cause. U-shaped events in radio light curves in the centimeter-wave band have previously been attributed to Extreme scattering events (ESE). ESEs are thought to be the result of lensing by compact plasma structures in the Galactic interstellar medium, but the precise nature of these plasma structures remains unknown. Since the strength of a plasma lens evolves with wavelength λ as {λ }2, the presence of correlated variations at over a wide wavelength range casts doubt on the canonical ESE interpretation for J1415+1320. In this paper, we critically examine the evidence for plasma lensing in J1415+1320. We compute limits on the lensing strength and the associated free-free opacity of the putative plasma lenses. We compare the observed and model ESE light curves, and also derive a lower limit on the lens distance based on the effects of parallax due to the Earth’s orbit around the Sun. We conclude that plasma lensing is not a viable interpretation for J1415+1320's light curves and that symmetric U-shaped features in the radio light curves of extragalactic sources do not present prima facie evidence for ESEs. The methodology presented here is generic enough to be applicable to any plasma-lensing candidate.

  15. Devil in the Details: Investigating Astrophysical Phenomena with Kepler Light Curves

    Jenkins, Jon Michael; SOC, Kepler; SO, Kepler; Kepler Science Team

    2011-05-01

    The light curves produced by the Kepler photometer are unprecedented in their photometric precision, completeness, and contiguity. Moreover, although Kepler was designed to detect 100 ppm changes in brightness corresponding to transits of Earth-size planets crossing Sun-size stars, the Kepler light curves preserve intrinsic intensity variations across a large dynamic range, including those of RR Lyrae stars, which can increase their brightness by more than a factor of two over a few hours. The large dynamic range and phenomenal photometric precision of Kepler promises to revolutionize the study of intrinsic stellar variability and a wide variety of variable stars on timescales from minutes to several years. In this paper, we describe the science pipeline processing that produces the uncorrected and the systematic error-corrected light curves, and give examples of residual instrumental artifacts that can be found in the data, such as those caused by thermal changes due to the position of the spacecraft with relation to the sun or heaters cycling on and off on various spacecraft components (which can change the shape of the telescope and alter its focus), as well as examples of processing artifacts that can occur. We also describe algorithms in development that promise to improve our ability to identify and remove instrumental signatures and further reduce the incidence of processing artifacts in the archival light curves, thereby increasing the usability of the corrected light curves for astrophysical investigations. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by the NASA Science Mission Directorate.

  16. Type IIP supernova light curves affected by the acceleration of red supergiant winds

    Moriya, Takashi J.; Förster, Francisco; Yoon, Sung-Chul; Gräfener, Götz; Blinnikov, Sergei I.

    2018-05-01

    We introduce the first synthetic light-curve model set of Type IIP supernovae exploded within circumstellar media in which the acceleration of the red supergiant winds is taken into account. Because wind acceleration makes the wind velocities near the progenitors low, the density of the immediate vicinity of the red supergiant supernova progenitors can be higher than that extrapolated by using a constant terminal wind velocity. Therefore, even if the mass-loss rate of the progenitor is relatively low, it can have a dense circumstellar medium at the immediate stellar vicinity and the early light curves of Type IIP supernovae are significantly affected by it. We adopt a simple β velocity law to formulate the wind acceleration. We provide bolometric and multicolour light curves of Type IIP supernovae exploding within such accelerated winds from the combinations of three progenitors, 12-16 M⊙; five β, 1-5; seven mass-loss rates, 10-5-10-2 M⊙ yr-1; and four explosion energies, (0.5-2) × 1051 erg. All the light-curve models are available at https://goo.gl/o5phYb. When the circumstellar density is sufficiently high, our models do not show a classical shock breakout as a consequence of the interaction with the dense and optically thick circumstellar media. Instead, they show a delayed `wind breakout', substantially affecting early light curves of Type IIP supernovae. We find that the mass-loss rates of the progenitors need to be 10-3-10-2 M⊙ yr-1 to explain typical rise times of 5-10 d in Type IIP supernovae assuming a dense circumstellar radius of 1015 cm.

  17. THE INFORMATION CONTENT IN ANALYTIC SPOT MODELS OF BROADBAND PRECISION LIGHT CURVES

    Walkowicz, Lucianne M. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08534 (United States); Basri, Gibor [Astronomy Department, University of California at Berkeley, Hearst Field Annex, Berkeley, CA 94720 (United States); Valenti, Jeff A. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)

    2013-04-01

    We present the results of numerical experiments to assess degeneracies in light curve models of starspots. Using synthetic light curves generated with the Cheetah starspot modeling code, we explore the extent to which photometric light curves constrain spot model parameters, including spot latitudes and stellar inclination. We also investigate the effects of spot parameters and differential rotation on one's ability to correctly recover rotation periods and differential rotation in the Kepler light curves. We confirm that in the absence of additional constraints on the stellar inclination, such as spectroscopic measurements of vsin i or occultations of starspots by planetary transits, the spot latitude and stellar inclination are difficult to determine uniquely from the photometry alone. We find that for models with no differential rotation, spots that appear on opposite hemispheres of the star may cause one to interpret the rotation period to be half of the true period. When differential rotation is included, the changing longitude separation between spots breaks the symmetry of the hemispheres and the correct rotation period is more likely to be found. The dominant period found via periodogram analysis is typically that of the largest spot. Even when multiple spots with periods representative of the star's differential rotation exist, if one spot dominates the light curve the signal of differential rotation may not be detectable from the periodogram alone. Starspot modeling is applicable to stars with a wider range of rotation rates than other surface imaging techniques (such as Doppler imaging), allows subtle signatures of differential rotation to be measured, and may provide valuable information on the distribution of stellar spots. However, given the inherent degeneracies and uncertainty present in starspot models, caution should be exercised in their interpretation.

  18. THE INFORMATION CONTENT IN ANALYTIC SPOT MODELS OF BROADBAND PRECISION LIGHT CURVES

    Walkowicz, Lucianne M.; Basri, Gibor; Valenti, Jeff A.

    2013-01-01

    We present the results of numerical experiments to assess degeneracies in light curve models of starspots. Using synthetic light curves generated with the Cheetah starspot modeling code, we explore the extent to which photometric light curves constrain spot model parameters, including spot latitudes and stellar inclination. We also investigate the effects of spot parameters and differential rotation on one's ability to correctly recover rotation periods and differential rotation in the Kepler light curves. We confirm that in the absence of additional constraints on the stellar inclination, such as spectroscopic measurements of vsin i or occultations of starspots by planetary transits, the spot latitude and stellar inclination are difficult to determine uniquely from the photometry alone. We find that for models with no differential rotation, spots that appear on opposite hemispheres of the star may cause one to interpret the rotation period to be half of the true period. When differential rotation is included, the changing longitude separation between spots breaks the symmetry of the hemispheres and the correct rotation period is more likely to be found. The dominant period found via periodogram analysis is typically that of the largest spot. Even when multiple spots with periods representative of the star's differential rotation exist, if one spot dominates the light curve the signal of differential rotation may not be detectable from the periodogram alone. Starspot modeling is applicable to stars with a wider range of rotation rates than other surface imaging techniques (such as Doppler imaging), allows subtle signatures of differential rotation to be measured, and may provide valuable information on the distribution of stellar spots. However, given the inherent degeneracies and uncertainty present in starspot models, caution should be exercised in their interpretation.

  19. Hierarchical Models for Type Ia Supernova Light Curves in the Optical and Near Infrared

    Mandel, Kaisey; Narayan, G.; Kirshner, R. P.

    2011-01-01

    I have constructed a comprehensive statistical model for Type Ia supernova optical and near infrared light curves. Since the near infrared light curves are excellent standard candles and are less sensitive to dust extinction and reddening, the combination of near infrared and optical data better constrains the host galaxy extinction and improves the precision of distance predictions to SN Ia. A hierarchical probabilistic model coherently accounts for multiple random and uncertain effects, including photometric error, intrinsic supernova light curve variations and correlations across phase and wavelength, dust extinction and reddening, peculiar velocity dispersion and distances. An improved BayeSN MCMC code is implemented for computing probabilistic inferences for individual supernovae and the SN Ia and host galaxy dust populations. I use this hierarchical model to analyze nearby Type Ia supernovae with optical and near infared data from the PAIRITEL, CfA3, and CSP samples and the literature. Using cross-validation to test the robustness of the model predictions, I find that the rms Hubble diagram scatter of predicted distance moduli is 0.11 mag for SN with optical and near infrared data versus 0.15 mag for SN with only optical data. Accounting for the dispersion expected from random peculiar velocities, the rms intrinsic prediction error is 0.08-0.10 mag for SN with both optical and near infrared light curves. I discuss results for the inferred intrinsic correlation structures of the optical-NIR SN Ia light curves and the host galaxy dust distribution captured by the hierarchical model. The continued observation and analysis of Type Ia SN in the optical and near infrared is important for improving their utility as precise and accurate cosmological distance indicators.

  20. CSI 2264: characterizing accretion-burst dominated light curves for young stars in NGC 2264

    Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Carey, Sean; Baglin, Annie; Alencar, Silvia; Hillenbrand, Lynne A.; Carpenter, John; Findeisen, Krzysztof; Venuti, Laura; Bouvier, Jerome; Turner, Neal J.; Plavchan, Peter; Terebey, Susan; Morales-Calderón, María; Micela, Giusi; Flaccomio, Ettore; Song, Inseok; Gutermuth, Rob; Hartmann, Lee

    2014-01-01

    Based on more than four weeks of continuous high-cadence photometric monitoring of several hundred members of the young cluster NGC 2264 with two space telescopes, NASA's Spitzer and the CNES CoRoT (Convection, Rotation, and planetary Transits), we provide high-quality, multi-wavelength light curves for young stellar objects whose optical variability is dominated by short-duration flux bursts, which we infer are due to enhanced mass accretion rates. These light curves show many brief—several hours to one day—brightenings at optical and near-infrared wavelengths with amplitudes generally in the range of 5%-50% of the quiescent value. Typically, a dozen or more of these bursts occur in a 30 day period. We demonstrate that stars exhibiting this type of variability have large ultraviolet (UV) excesses and dominate the portion of the u – g versus g – r color-color diagram with the largest UV excesses. These stars also have large Hα equivalent widths, and either centrally peaked, lumpy Hα emission profiles or profiles with blueshifted absorption dips associated with disk or stellar winds. Light curves of this type have been predicted for stars whose accretion is dominated by Rayleigh-Taylor instabilities at the boundary between their magnetosphere and inner circumstellar disk, or where magneto-rotational instabilities modulate the accretion rate from the inner disk. Among the stars with the largest UV excesses or largest Hα equivalent widths, light curves with this type of variability greatly outnumber light curves with relatively smooth sinusoidal variations associated with long-lived hot spots. We provide quantitative statistics for the average duration and strength of the accretion bursts and for the fraction of the accretion luminosity associated with these bursts.

  1. High precision innovative micropump for artificial pancreas

    Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.

    2014-03-01

    The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.

  2. The Physics of Type Ia Supernova Light Curves. I. Analytic Results and Time Dependence

    Pinto, Philip A.; Eastman, Ronald G.

    2000-01-01

    We develop an analytic solution of the radiation transport problem for Type Ia supernovae (SNe Ia) and show that it reproduces bolometric light curves produced by more detailed calculations under the assumption of a constant-extinction coefficient. This model is used to derive the thermal conditions in the interior of SNe Ia and to study the sensitivity of light curves to various properties of the underlying supernova explosions. Although the model is limited by simplifying assumptions, it is adequate for demonstrating that the relationship between SNe Ia maximum-light luminosity and rate of decline is most easily explained if SNe Ia span a range in mass. The analytic model is also used to examine the size of various terms in the transport equation under conditions appropriate to maximum light. For instance, the Eulerian and advective time derivatives are each shown to be of the same order of magnitude as other order v/c terms in the transport equation. We conclude that a fully time-dependent solution to the transport problem is needed in order to compute SNe Ia light curves and spectra accurate enough to distinguish subtle differences of various explosion models. (c) 2000 The American Astronomical Society

  3. High precision relative position sensing system for formation flying spacecraft

    National Aeronautics and Space Administration — We propose to develop and test an optical sensing system that provides high precision relative position sensing for formation flying spacecraft.  A high precision...

  4. Fiber Scrambling for High Precision Spectrographs

    Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

    2011-05-01

    The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

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

    Cantrell, Andrew Glenn

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

  6. Mass estimates from optical-light curves for binary X-ray sources

    Avni, Y.

    1978-01-01

    The small amplitude variations with orbital phase of the optical light from X-ray binaries are caused by the changing geometrical aspect of the primary as seen by a fixed observer. The shape and the amplitude of the light curve depends on the stellar masses and on the orbital elements. The light curve can, therefore, be used to determine, or set limits on, the parameters of the binary system. A self-consistent procedure for the calculation of the light curve can be formulated if the primary is formulated if the primary is uniformly rotating at an angular velocity equal to the angular velocity of its orbital revolution in a circular orbit, and if the primary is in a hydrostatic and radiative equilibrium in the co-rotating frame. When the primary is further approximated to be centrally condensed, the above set of assumptions is called the standard picture. The standard picture is described, its validity discussed and its application to various systems reviewed. (C.F.)

  7. Searching for transits in the WTS with the difference imaging light curves

    Zendejas Dominguez, Jesus

    2013-12-01

    The search for exo-planets is currently one of the most exiting and active topics in astronomy. Small and rocky planets are particularly the subject of intense research, since if they are suitably located from their host star, they may be warm and potentially habitable worlds. On the other hand, the discovery of giant planets in short-period orbits provides important constraints on models that describe planet formation and orbital migration theories. Several projects are dedicated to discover and characterize planets outside of our solar system. Among them, the Wide-Field Camera Transit Survey (WTS) is a pioneer program aimed to search for extra-solar planets, that stands out for its particular aims and methodology. The WTS has been in operation since August 2007 with observations from the United Kingdom Infrared Telescope, and represents the first survey that searches for transiting planets in the near-infrared wavelengths; hence the WTS is designed to discover planets around M-dwarfs. The survey was originally assigned about 200 nights, observing four fields that were selected seasonally (RA = 03, 07, 17 and 19h) during a year. The images from the survey are processed by a data reduction pipeline, which uses aperture photometry to construct the light curves. For the most complete field (19h-1145 epochs) in the survey, we produce an alternative set of light curves by using the method of difference imaging, which is a photometric technique that has shown important advantages when used in crowded fields. A quantitative comparison between the photometric precision achieved with both methods is carried out in this work. We remove systematic effects using the sysrem algorithm, scale the error bars on the light curves, and perform a comparison of the corrected light curves. The results show that the aperture photometry light curves provide slightly better precision for objects with J detect transits in the WTS light curves, we use a modified version of the box

  8. Radio emission from Supernovae and High Precision Astrometry

    Perez-Torres, M. A.

    1999-11-01

    The present thesis work makes contributions in two scientific fronts: differential astrometry over the largest angular scales ever attempted (approx. 15 arcdegrees) and numerical simulations of radio emission from very young supernovae. In the first part, we describe the results of the use of very-long-baseline interferometry (VLBI) in one experiment designed to measure with very high precision the angular distance between the radio sources 1150+812 (QSO) and 1803+784 (BL Lac). We observed the radio sources on 19 November 1993 using an intercontinental array of radio telescopes, which simultaneously recorded at 2.3 and 8.4 GHz. VLBI differential astrometry is capable, Nature allowing, of yielding source positions with precisions well below the milliarcsecond level. To achieve this precision, we first had to accurately model the rotation of the interferometric fringes via the most precise models of Earth Orientation Parameters (EOP; precession, polar motion and UT1, nutation). With this model, we successfully connected our phase delay data at both frequencies and, using difference astrometric techniques, determined the coordinates of 1803+784 relative to those of 1150+812-within the IERS reference frame--with an standard error of about 0.6 mas in each coordinate. We then corrected for several effects including propagation medium (mainly the atmosphere and ionosphere), and opacity and source-structure effects within the radio sources. We stress that our dual-frequency measurements allowed us to accurately subtract the ionosphere contribution from our data. We also used GPS-based TEC measurements to independently find the ionosphere contribution, and showed that these contributions agree with our dual-frequency measurements within about 2 standard deviations in the less favorables cases (the longest baselines), but are usually well within one standard deviation. Our estimates of the relative positions, whether using dual-frequency-based or GPS-based ionosphere

  9. High precision isotopic ratio analysis of volatile metal chelates

    Hachey, D.L.; Blais, J.C.; Klein, P.D.

    1980-01-01

    High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

  10. Corot 310266512: A Light Curve With Primary, Secondary And Tertiary Eclipses

    Fernández Fernández Javier

    2015-01-01

    Full Text Available We present the photometric study of an interesting target in the CoRoT exoplanet database: CoRoT 310266512. Its light curve shows primary, secondary and tertiary eclipses that suggests the presence of at least three celestial bodies. The primary and secondary eclipses have the same orbital period, 7.42 days, and the tertiary eclipse has an orbital period of 3.27 days. Two of the tertiary eclipses fall within a primary eclipse and a secondary eclipse. The properties of the light curve indicate the presence of two physically separated systems. The primary and secondary eclipses corresponds to a binary system (System I. The tertiary eclipses correspond to a star-planet system or a star-dwarf system (System II. Some parameters of these two systems are obtained from JKTEBOP [1] program.

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

    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.

  12. VizieR Online Data Catalog: Praesepe members light curves (Kovacs+, 2014)

    Kovacs, G.; Hartman, J. D.; Bakos, G. A.; Quinn, S. N.; Penev, K.; Latham, D. W.; Bhatti, W.; Csubry, Z.; de Val-Borro, M.

    2014-07-01

    Light curves used in the time series analysis of Praesepe are presented. There are 381 light curves on instrumental Sloan r' magnitude scale with the zero points determined by the 2MASS magnitudes according to Eq. (1) of the paper. We present two types of magnitudes: a) external parameter decorrelated (EPD) and b), the ones obtained after the application of a trend filtering algorithm (TFA) on the EPD time series. These two methods are briefly described in the paper and in detail in the references therein. Here we just note that both methods are intended to filter out systematics due to environmental effects (instrumental, weather, etc.). For TFA filtering we used 600 templates and did not apply signal reconstruction. (5 data files).

  13. Spotted star light curve numerical modeling technique and its application to HII 1883 surface imaging

    Kolbin, A. I.; Shimansky, V. V.

    2014-04-01

    We developed a code for imaging the surfaces of spotted stars by a set of circular spots with a uniform temperature distribution. The flux from the spotted surface is computed by partitioning the spots into elementary areas. The code takes into account the passing of spots behind the visible stellar limb, limb darkening, and overlapping of spots. Modeling of light curves includes the use of recent results of the theory of stellar atmospheres needed to take into account the temperature dependence of flux intensity and limb darkening coefficients. The search for spot parameters is based on the analysis of several light curves obtained in different photometric bands. We test our technique by applying it to HII 1883.

  14. EXTRASOLAR STORMS: PRESSURE-DEPENDENT CHANGES IN LIGHT-CURVE PHASE IN BROWN DWARFS FROM SIMULTANEOUS HST AND SPITZER OBSERVATIONS

    Yang, Hao; Apai, Dániel; Karalidi, Theodora [Department of Astronomy, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Marley, Mark S. [NASA Ames Research Center, Naval Air Station, Moffett Field, Mountain View, CA 94035 (United States); Flateau, Davin [Department of Planetary Sciences, 1629 E. University Blvd., Tucson, AZ 85721 (United States); Showman, Adam P. [Department of Planetary Sciences, University of Arizona, 1629 University Blvd., Tucson, AZ 85721 (United States); Metchev, Stanimir [The University of Western Ontario, Department of Physics and Astronomy, Centre for Planetary Science and Exploration, 1151 Richmond St., London, ON N6A 3K7 (Canada); Buenzli, Esther [Institute for Astronomy, ETH Zürich Wolfgang-Pauli-Str. 27, 8093 Zürich (Switzerland); Radigan, Jacqueline [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Artigau, Étienne [Département de Physique, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montréal, QC H3C 3J7 (Canada); Lowrance, Patrick J. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Burgasser, Adam J., E-mail: haoyang@email.arizona.edu, E-mail: apai@arizona.edu [Center for Astrophysics and Space Science, University of California, San Diego, La Jolla, CA 92093 (United States)

    2016-07-20

    We present Spitzer /Infrared Array Camera Ch1 and Ch2 monitoring of six brown dwarfs during eight different epochs over the course of 20 months. For four brown dwarfs, we also obtained simulataneous Hubble Space Telescope ( HST )/WFC3 G141 grism spectra during two epochs and derived light curves in five narrowband filters. Probing different pressure levels in the atmospheres, the multiwavelength light curves of our six targets all exhibit variations, and the shape of the light curves evolves over the timescale of a rotation period, ranging from 1.4 to 13 hr. We compare the shapes of the light curves and estimate the phase shifts between the light curves observed at different wavelengths by comparing the phase of the primary Fourier components. We use state-of-the-art atmosphere models to determine the flux contribution of different pressure layers to the observed flux in each filter. We find that the light curves that probe higher pressures are similar and in phase, but are offset and often different from the light curves that probe lower pressures. The phase differences between the two groups of light curves suggest that the modulations seen at lower and higher pressures may be introduced by different cloud layers.

  15. A Simple yet Accurate Method for Students to Determine Asteroid Rotation Periods from Fragmented Light Curve Data

    Beare, R. A.

    2008-01-01

    Professional astronomers use specialized software not normally available to students to determine the rotation periods of asteroids from fragmented light curve data. This paper describes a simple yet accurate method based on Microsoft Excel[R] that enables students to find periods in asteroid light curve and other discontinuous time series data of…

  16. CfA3: 185 TYPE Ia SUPERNOVA LIGHT CURVES FROM THE CfA

    Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Bakos, Gaspar; Berlind, Perry; Brown, Warren R.; Caldwell, Nelson; Calkins, Mike; Cho, Richard; Contreras, Maria; Jha, Saurabh; Matheson, Tom; Modjaz, Maryam; Rest, Armin; Michael Wood-Vasey, W.; Barton, Elizabeth J.; Bragg, Ann; Briceno, Cesar; Ciupik, Larry; Dendy, Kristi-Concannon

    2009-01-01

    We present multiband photometry of 185 type-Ia supernovae (SNe Ia), with over 11,500 observations. These were acquired between 2001 and 2008 at the F. L. Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA). This sample contains the largest number of homogeneously observed and reduced nearby SNe Ia (z ∼< 0.08) published to date. It more than doubles the nearby sample, bringing SN Ia cosmology to the point where systematic uncertainties dominate. Our natural system photometry has a precision of ∼<0.02 mag in BVRIr'i' and ∼<0.04 mag in U for points brighter than 17.5 mag. We also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system BVRIr'i' photometry and 0.07 mag for U. Comparisons of our standard system photometry with published SN Ia light curves and comparison stars, where available for the same SN, reveal agreement at the level of a few hundredths mag in most cases. We find that 1991bg-like SNe Ia are sufficiently distinct from other SNe Ia in their color and light-curve-shape/luminosity relation that they should be treated separately in light-curve/distance fitter training samples. The CfA3 sample will contribute to the development of better light-curve/distance fitters, particularly in the few dozen cases where near-infrared photometry has been obtained and, together, can help disentangle host-galaxy reddening from intrinsic supernova color, reducing the systematic uncertainty in SN Ia distances due to dust.

  17. VizieR Online Data Catalog: Ji light curves of WTS-2 (Birkby+, 2014)

    Birkby, J. L.; Cappetta, M.; Cruz, P.; Koppenhoefer, J.; Ivanyuk, O.; Mustill, A. J.; Hodgkin, S. T.; Pinfield, D. J.; Sipocz, B.; Kovacs, G.; Saglia, R.; Pavlenko, Y.; Barrado, D.; Bayo, A.; Campbell, D.; Catalan, S.; Fossati, L.; Galvez-Ortiz, M.-C.; Kenworthy, M.; Lillo-Box, J.; Martin, E. L.; Mislis, D.; de Mooij, E. J. W.; Nefs, S. V.; Snellen, I. A. G.; Stoev, H.; Zendejas, J.; Del Burgo, C.; Barnes, J.; Goulding, N.; Haswell, C. A.; Kuznetsov, M.; Lodieu, N.; Murgas, F.; Palle, E.; Solano, E.; Steele, P.; Tata, R.

    2015-07-01

    The infrared light curves of the WTS were generated from time series photometry taken with the WFCAM imager mounted at the prime focus of UKIRT. In order to confirm the transit of WTS-2 b and to help constrain the transit model, on 2010 July 18 we obtained further time series photometry in the Sloan i band using the Wide Field Camera (WFC) on the 2.5m Isaac Newton Telescope (INT) at Roque de Los Muchachos, La Palma. (2 data files).

  18. Ensemble Learning Method for Outlier Detection and its Application to Astronomical Light Curves

    Nun, Isadora; Protopapas, Pavlos; Sim, Brandon; Chen, Wesley

    2016-09-01

    Outlier detection is necessary for automated data analysis, with specific applications spanning almost every domain from financial markets to epidemiology to fraud detection. We introduce a novel mixture of the experts outlier detection model, which uses a dynamically trained, weighted network of five distinct outlier detection methods. After dimensionality reduction, individual outlier detection methods score each data point for “outlierness” in this new feature space. Our model then uses dynamically trained parameters to weigh the scores of each method, allowing for a finalized outlier score. We find that the mixture of experts model performs, on average, better than any single expert model in identifying both artificially and manually picked outliers. This mixture model is applied to a data set of astronomical light curves, after dimensionality reduction via time series feature extraction. Our model was tested using three fields from the MACHO catalog and generated a list of anomalous candidates. We confirm that the outliers detected using this method belong to rare classes, like Novae, He-burning, and red giant stars; other outlier light curves identified have no available information associated with them. To elucidate their nature, we created a website containing the light-curve data and information about these objects. Users can attempt to classify the light curves, give conjectures about their identities, and sign up for follow up messages about the progress made on identifying these objects. This user submitted data can be used further train of our mixture of experts model. Our code is publicly available to all who are interested.

  19. Spotted star mapping by light curve inversion: Tests and application to HD 12545

    Kolbin, A. I.; Shimansky, V. V.

    2013-06-01

    A code for mapping the surfaces of spotted stars is developed. The concept of the code is to analyze rotational-modulated light curves. We simulate the process of reconstruction for the star surface and the results of simulation are presented. The reconstruction atrifacts caused by the ill-posed nature of the problem are deduced. The surface of the spotted component of system HD 12545 is mapped using the procedure.

  20. High precision power supplies for the National Synchrotron Light Source

    Olsen, R.; Langenbach, H.

    1987-04-01

    Since beam stability depends to a considerable degree on the stability of the magnet power supplies, and it is desired to push for 3 GeV operation, it was required that new power supplies be obtained for the quadrupoles and sextupoles. These power supplies were to have the lowest ripple that could be reasonably achieved, and were to have a current regulation of better than 10 PPM. In addition, since they operate over a 5 : 1 voltage range, it was considered desirable to ensure that they operated with a good power factor over the operating range. The dipole power supply was modified to use the techniques employed in the smaller supplies

  1. Use of supernovae light curves for testing the expansion hypothesis and other cosmological relations

    Rust, B.W.

    1974-01-01

    This thesis is primarily concerned with a test of the expansion hypothesis based on the relation Δt/sub obs/ = (1 + V/sub r//c)Δt/sub int/ where Δt/sub int/ is the time lapse characterizing some phenomenon in a distant galaxy, Δt/sub obs/ is the observed time lapse and V/sub r/ is the symbolic velocity of recession. If the red shift is a Doppler effect, the observed time lapse should be lengthened by the same factor as the wave length of the light. Many authors have suggested type I supernovae for such a test because of their great luminosity and the uniformity of their light curves, but apparently the test has heretofore never actually been performed. Thirty-six light curves were gathered from the literature and one (SN1971i) was measured. All of the light curves were reduced to a common (m/sub pg/) photometric system. The comparison time lapse, Δt/sub c/, was taken to be the time required for the brightness to fall from 0.5 m below peak to 2.5 m below peak. The straight line regression of Δt/sub c/ on V/sub r/ gives a correlation coefficient significant at the 93 percent level, and the simple static Euclidean hypothesis is rejected at that level. The regression line also deviates from the prediction of the classical expansion hypothesis. Better agreement was obtained using the chronogeometric theory of I. E. Segal ( []972 Astron. and Astrophys. 18, 143), but the scatter in the present data makes it impossible to distinguish between these alternate hypotheses at the 95 percent confidence level. The question of how many additional light curves would be needed to give definite tests is addressed. It is shown that at the present rate of supernova discoveries, only a few more years would be required to obtain the necessary data if light curves are systematically measured for the more distant supernovae. (Diss. Abstr. Int., B)

  2. A powerful test for weak periodic signals with unknown light curve shape in sparse data

    Jager De, O.C.; Raubenheimer, B.C.; Swanepoel, J.W.H.

    1989-01-01

    A problem with most tests for periodicity is that they are powerful enough to detect only certain kinds of periodic shapes in the case of weak signals. This causes a selection effect with the identification of weak periodic signals. A new test for uniformity called the H-test is derived for which the probability distribution is an exponential function. This test is shown to have a very good power against most light curve shapes encountered in X- and γ-ray Astronomy and therefore makes the detection of sources with a larger variety of shapes possible. The use of the H-test is suggested if no a priori information about the light curve shape is available. It is also shown how the probability distribution of the test statistics changes when a periodicity search is conducted using very small steps in the period or frequency range. The flux sensitivity for various light curve shapes is also derived for a few tests and this flux is on average a minimum for the H-test

  3. New limb-darkening coefficients for modeling binary star light curves

    Van Hamme, W.

    1993-01-01

    We present monochromatic, passband-specific, and bolometric limb-darkening coefficients for a linear as well as nonlinear logarithmic and square root limb-darkening laws. These coefficients, including the bolometric ones, are needed when modeling binary star light curves with the latest version of the Wilson-Devinney light curve progam. We base our calculations on the most recent ATLAS stellar atmosphere models for solar chemical composition stars with a wide range of effective temperatures and surface gravitites. We examine how well various limb-darkening approximations represent the variation of the emerging specific intensity across a stellar surface as computed according to the model. For binary star light curve modeling purposes, we propose the use of a logarithmic or a square root law. We design our tables in such a manner that the relative quality of either law with respect to another can be easily compared. Since the computation of bolometric limb-darkening coefficients first requires monochromatic coefficients, we also offer tables of these coefficients (at 1221 wavelength values between 9.09 nm and 160 micrometer) and tables of passband-specific coefficients for commonly used photometric filters.

  4. Absolute Distances to Nearby Type Ia Supernovae via Light Curve Fitting Methods

    Vinkó, J.; Ordasi, A.; Szalai, T.; Sárneczky, K.; Bányai, E.; Bíró, I. B.; Borkovits, T.; Hegedüs, T.; Hodosán, G.; Kelemen, J.; Klagyivik, P.; Kriskovics, L.; Kun, E.; Marion, G. H.; Marschalkó, G.; Molnár, L.; Nagy, A. P.; Pál, A.; Silverman, J. M.; Szakáts, R.; Szegedi-Elek, E.; Székely, P.; Szing, A.; Vida, K.; Wheeler, J. C.

    2018-06-01

    We present a comparative study of absolute distances to a sample of very nearby, bright Type Ia supernovae (SNe) derived from high cadence, high signal-to-noise, multi-band photometric data. Our sample consists of four SNe: 2012cg, 2012ht, 2013dy and 2014J. We present new homogeneous, high-cadence photometric data in Johnson–Cousins BVRI and Sloan g‧r‧i‧z‧ bands taken from two sites (Piszkesteto and Baja, Hungary), and the light curves are analyzed with publicly available light curve fitters (MLCS2k2, SNooPy2 and SALT2.4). When comparing the best-fit parameters provided by the different codes, it is found that the distance moduli of moderately reddened SNe Ia agree within ≲0.2 mag, and the agreement is even better (≲0.1 mag) for the highest signal-to-noise BVRI data. For the highly reddened SN 2014J the dispersion of the inferred distance moduli is slightly higher. These SN-based distances are in good agreement with the Cepheid distances to their host galaxies. We conclude that the current state-of-the-art light curve fitters for Type Ia SNe can provide consistent absolute distance moduli having less than ∼0.1–0.2 mag uncertainty for nearby SNe. Still, there is room for future improvements to reach the desired ∼0.05 mag accuracy in the absolute distance modulus.

  5. THREE FUNDAMENTAL PERIODS IN AN 87 YEAR LIGHT CURVE OF THE SYMBIOTIC STAR MWC 560

    Leibowitz, Elia M.; Formiggini, Liliana, E-mail: elia@astro.tau.ac.il [The Wise Observatory and the School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

    2015-08-15

    We construct a visual light curve of the symbiotic star MWC covering the last 87 years of its history. The data were assembled from the literature and from the AAVSO data bank. Most of the periodic components of the system brightness variation can be accounted for by the operation of three basic clocks of the periods P1 = 19,000 days, P2 = 1943 days, and P3 = 722 days. These periods can plausibly, and consistently with the observations, be attributed to three physical mechanisms in the system: the working of a solar-like magnetic dynamo cycle in the outer layers of the giant star of the system, the binary orbit cycle, and the sidereal rotation cycle of the giant star. MWC 560 is the seventh symbiotic star with historical light curves that reveal similar basic characteristics of the systems. The light curves of all these stars are well interpreted on the basis of the current understanding of the physical processes that are the major sources of the optical luminosity of these symbiotic systems.

  6. IMAGING STARSPOT EVOLUTION ON KEPLER TARGET KIC 5110407 USING LIGHT-CURVE INVERSION

    Roettenbacher, Rachael M.; Monnier, John D.; Harmon, Robert O.; Barclay, Thomas; Still, Martin

    2013-01-01

    The Kepler target KIC 5110407, a K-type star, shows strong quasi-periodic light curve fluctuations likely arising from the formation and decay of spots on the stellar surface rotating with a period of 3.4693 days. Using an established light-curve inversion algorithm, we study the evolution of the surface features based on Kepler space telescope light curves over a period of two years (with a gap of .25 years). At virtually all epochs, we detect at least one large spot group on the surface causing a 1%-10% flux modulation in the Kepler passband. By identifying and tracking spot groups over a range of inferred latitudes, we measured the surface differential rotation to be much smaller than that found for the Sun. We also searched for a correlation between the 17 stellar flares that occurred during our observations and the orientation of the dominant surface spot at the time of each flare. No statistically significant correlation was found except perhaps for the very brightest flares, suggesting that most flares are associated with regions devoid of spots or spots too small to be clearly discerned using our reconstruction technique. While we may see hints of long-term changes in the spot characteristics and flare statistics within our current data set, a longer baseline of observation will be needed to detect the existence of a magnetic cycle in KIC 5110407.

  7. Multi-Band Light Curves from Two-Dimensional Simulations of Gamma-Ray Burst Afterglows

    MacFadyen, Andrew

    2010-01-01

    The dynamics of gamma-ray burst outflows is inherently multi-dimensional. 1.) We present high resolution two-dimensional relativistic hydrodynamics simulations of GRBs in the afterglow phase using adaptive mesh refinement (AMR). Using standard synchrotron radiation models, we compute multi-band light curves, from the radio to X-ray, directly from the 2D hydrodynamics simulation data. We will present on-axis light curves for both constant density and wind media. We will also present off-axis light curves relevant for searches for orphan afterglows. We find that jet breaks are smoothed due to both off-axis viewing and wind media effects. 2.) Non-thermal radiation mechanisms in GRB afterglows require substantial magnetic field strengths. In turbulence driven by shear instabilities in relativistic magnetized gas, we demonstrate that magnetic field is naturally amplified to half a percent of the total energy (epsilon B = 0.005). We will show high resolution three dimensional relativistic MHD simulations of this process as well as particle in cell (PIC) simulations of mildly relativistic collisionless shocks.

  8. THE LICK AGN MONITORING PROJECT: PHOTOMETRIC LIGHT CURVES AND OPTICAL VARIABILITY CHARACTERISTICS

    Walsh, Jonelle L.; Bentz, Misty C.; Barth, Aaron J.; Minezaki, Takeo; Sakata, Yu; Yoshii, Yuzuru; Baliber, Nairn; Bennert, Vardha Nicola; Street, Rachel A.; Treu, Tommaso; Li Weidong; Filippenko, Alexei V.; Stern, Daniel; Brown, Timothy M.; Canalizo, Gabriela; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Woo, Jong-Hak

    2009-01-01

    The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with the intent of measuring the masses of their central black holes using reverberation mapping. The sample includes 12 galaxies selected to have black holes with masses roughly in the range 10 6 -10 7 M sun , as well as the well-studied active galactic nucleus (AGN) NGC 5548. In conjunction with a spectroscopic monitoring campaign, we obtained broadband B and V images on most nights from 2008 February through 2008 May. The imaging observations were carried out by four telescopes: the 0.76 m Katzman Automatic Imaging Telescope, the 2 m Multicolor Active Galactic Nuclei Monitoring telescope, the Palomar 60 inch (1.5 m) telescope, and the 0.80 m Tenagra II telescope. Having well-sampled light curves over the course of a few months is useful for obtaining the broad-line reverberation lag and black hole mass, and also allows us to examine the characteristics of the continuum variability. In this paper, we discuss the observational methods and the photometric measurements, and present the AGN continuum light curves. We measure various variability characteristics of each of the light curves. We do not detect any evidence for a time lag between the B- and V-band variations, and we do not find significant color variations for the AGNs in our sample.

  9. THREE FUNDAMENTAL PERIODS IN AN 87 YEAR LIGHT CURVE OF THE SYMBIOTIC STAR MWC 560

    Leibowitz, Elia M.; Formiggini, Liliana

    2015-01-01

    We construct a visual light curve of the symbiotic star MWC covering the last 87 years of its history. The data were assembled from the literature and from the AAVSO data bank. Most of the periodic components of the system brightness variation can be accounted for by the operation of three basic clocks of the periods P1 = 19,000 days, P2 = 1943 days, and P3 = 722 days. These periods can plausibly, and consistently with the observations, be attributed to three physical mechanisms in the system: the working of a solar-like magnetic dynamo cycle in the outer layers of the giant star of the system, the binary orbit cycle, and the sidereal rotation cycle of the giant star. MWC 560 is the seventh symbiotic star with historical light curves that reveal similar basic characteristics of the systems. The light curves of all these stars are well interpreted on the basis of the current understanding of the physical processes that are the major sources of the optical luminosity of these symbiotic systems

  10. The Carnegie Supernova Project I. Analysis of stripped-envelope supernova light curves

    Taddia, F.; Stritzinger, M. D.; Bersten, M.; Baron, E.; Burns, C.; Contreras, C.; Holmbo, S.; Hsiao, E. Y.; Morrell, N.; Phillips, M. M.; Sollerman, J.; Suntzeff, N. B.

    2018-02-01

    Stripped-envelope (SE) supernovae (SNe) include H-poor (Type IIb), H-free (Type Ib), and He-free (Type Ic) events thought to be associated with the deaths of massive stars. The exact nature of their progenitors is a matter of debate with several lines of evidence pointing towards intermediate mass (MinitCarnegie Supernova Project (CSP-I) that are unparalleled in terms of photometric accuracy and wavelength range. Light-curve parameters are estimated through the fits of an analytical function and trends are searched for among the resulting fit parameters. Detailed inspection of the dataset suggests a tentative correlation between the peak absolute B-band magnitude and Δm15(B), while the post maximum light curves reveals a correlation between the late-time linear slope and Δm15. Making use of the full set of optical and near-IR photometry, combined with robust host-galaxy extinction corrections, comprehensive bolometric light curves are constructed and compared to both analytic and hydrodynamical models. This analysis finds consistent results among the two different modeling techniques and from the hydrodynamical models we obtained ejecta masses of 1.1-6.2M⊙, 56Ni masses of 0.03-0.35M⊙, and explosion energies (excluding two SNe Ic-BL) of 0.25-3.0 × 1051 erg. Our analysis indicates that adopting κ = 0.07 cm2 g-1 as the mean opacity serves to be a suitable assumption when comparing Arnett-model results to those obtained from hydrodynamical calculations. We also find that adopting He I and O I line velocities to infer the expansion velocity in He-rich and He-poor SNe, respectively, provides ejecta masses relatively similar to those obtained by using the Fe II line velocities, although the use of Fe II as a diagnostic does imply higher explosion energies. The inferred range of ejecta masses are compatible with intermediate mass (MZAMS ≤ 20M⊙) progenitor stars in binary systems for the majority of SE SNe. Furthermore, our hydrodynamical modeling of the

  11. Spectral optimization simulation of white light based on the photopic eye-sensitivity curve

    Dai, Qi, E-mail: qidai@tongji.edu.cn [College of Architecture and Urban Planning, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Institute for Advanced Study, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Key Laboratory of Ecology and Energy-saving Study of Dense Habitat (Tongji University), Ministry of Education, 1239 Siping Road, Shanghai 200092 (China); Hao, Luoxi; Lin, Yi; Cui, Zhe [College of Architecture and Urban Planning, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Key Laboratory of Ecology and Energy-saving Study of Dense Habitat (Tongji University), Ministry of Education, 1239 Siping Road, Shanghai 200092 (China)

    2016-02-07

    Spectral optimization simulation of white light is studied to boost maximum attainable luminous efficacy of radiation at high color-rendering index (CRI) and various color temperatures. The photopic eye-sensitivity curve V(λ) is utilized as the dominant portion of white light spectra. Emission spectra of a blue InGaN light-emitting diode (LED) and a red AlInGaP LED are added to the spectrum of V(λ) to match white color coordinates. It is demonstrated that at the condition of color temperature from 2500 K to 6500 K and CRI above 90, such white sources can achieve spectral efficacy of 330–390 lm/W, which is higher than the previously reported theoretical maximum values. We show that this eye-sensitivity-based approach also has advantages on component energy conversion efficiency compared with previously reported optimization solutions.

  12. Spectral optimization simulation of white light based on the photopic eye-sensitivity curve

    Dai, Qi; Hao, Luoxi; Lin, Yi; Cui, Zhe

    2016-01-01

    Spectral optimization simulation of white light is studied to boost maximum attainable luminous efficacy of radiation at high color-rendering index (CRI) and various color temperatures. The photopic eye-sensitivity curve V(λ) is utilized as the dominant portion of white light spectra. Emission spectra of a blue InGaN light-emitting diode (LED) and a red AlInGaP LED are added to the spectrum of V(λ) to match white color coordinates. It is demonstrated that at the condition of color temperature from 2500 K to 6500 K and CRI above 90, such white sources can achieve spectral efficacy of 330–390 lm/W, which is higher than the previously reported theoretical maximum values. We show that this eye-sensitivity-based approach also has advantages on component energy conversion efficiency compared with previously reported optimization solutions

  13. Red light-induced shift of the fluence-response curve for first positive curvature of maize [Zea mays] coleoptiles

    Hofmann, E.; Schäfer, E.

    1987-01-01

    The fluence-response curve for first positive phototropic curvture of dark-grown maize coleoptiles is shifted to ten-fold higher fluences if the coieoptiles are irradiated with red light 2 h prior to the phototropic induction with blue light. Fluence-response curves for this red-induced shift were obtained with unilateral red irradiations 2 h prior to inductive blue pulses of different fluences. They differ significantly depending on whether the red light was given from the same side as or the opposite side to the respective inductive blue pulse, thus demonstrating that the red light effect is a local response of the coleoptile. The fluence-response curves for an inductive blue pulse in the ascending part were compared with those for an inductive blue pulse in the descending part of the fluence-response curve for blue light induced phototropism. They are quite different in threshold of red light sensitivity and shape for irradiations from both the same and the opposite sides. This offers evidence for the hypothesis that at least two different photosystems are involved in phototropism, and that they are modulated differently by a red light preirradiation. All these fluence-response curves indicate that it is possible to increase the response in the coleoptile, if the red light preirradiation is given opposite to the inductive blue pulse. This is supported by blue light fluence-response curves obtained after a weak unilateral red preirradiation. (author)

  14. Estimation of error on the cross-correlation, phase and time lag between evenly sampled light curves

    Misra, R.; Bora, A.; Dewangan, G.

    2018-04-01

    Temporal analysis of radiation from Astrophysical sources like Active Galactic Nuclei, X-ray Binaries and Gamma-ray bursts provides information on the geometry and sizes of the emitting regions. Establishing that two light-curves in different energy bands are correlated, and measuring the phase and time-lag between them is an important and frequently used temporal diagnostic. Generally the estimates are done by dividing the light-curves into large number of adjacent intervals to find the variance or by using numerically expensive simulations. In this work we have presented alternative expressions for estimate of the errors on the cross-correlation, phase and time-lag between two shorter light-curves when they cannot be divided into segments. Thus the estimates presented here allow for analysis of light-curves with relatively small number of points, as well as to obtain information on the longest time-scales available. The expressions have been tested using 200 light curves simulated from both white and 1 / f stochastic processes with measurement errors. We also present an application to the XMM-Newton light-curves of the Active Galactic Nucleus, Akn 564. The example shows that the estimates presented here allow for analysis of light-curves with relatively small (∼ 1000) number of points.

  15. The diverse broad-band light-curves of Swift GRBs reproduced with the cannonball model

    Dado, Shlomo; De Rújula, A

    2009-01-01

    Two radiation mechanisms, inverse Compton scattering (ICS) and synchrotron radiation (SR), suffice within the cannonball (CB) model of long gamma ray bursts (LGRBs) and X-ray flashes (XRFs) to provide a very simple and accurate description of their observed prompt emission and afterglows. Simple as they are, the two mechanisms and the burst environment generate the rich structure of the light curves at all frequencies and times. This is demonstrated for 33 selected Swift LGRBs and XRFs, which are well sampled from early time until late time and well represent the entire diversity of the broad band light curves of Swift LGRBs and XRFs. Their prompt gamma-ray and X-ray emission is dominated by ICS of glory light. During their fast decline phase, ICS is taken over by SR which dominates their broad band afterglow. The pulse shape and spectral evolution of the gamma-ray peaks and the early-time X-ray flares, and even the delayed optical `humps' in XRFs, are correctly predicted. The canonical and non-canonical X-ra...

  16. APSIDAL MOTION AND A LIGHT CURVE SOLUTION FOR 13 LMC ECCENTRIC ECLIPSING BINARIES

    Zasche, P.; Wolf, M.; Vraštil, J.; Pilarcik, L. [Astronomical Institute, Charles University in Prague, Faculty of Mathematics and Physics, CZ-180 00 Praha 8, V Holešovičkách 2 (Czech Republic)

    2015-12-15

    New CCD observations for 13 eccentric eclipsing binaries from the Large Magellanic Cloud were carried out using the Danish 1.54 m telescope located at the La Silla Observatory in Chile. These systems were observed for their times of minimum and 56 new minima were obtained. These are needed for accurate determination of the apsidal motion. Besides that, in total 436 times of minimum were derived from the photometric databases OGLE and MACHO. The O – C diagrams of minimum timings for these B-type binaries were analyzed and the parameters of the apsidal motion were computed. The light curves of these systems were fitted using the program PHOEBE, giving the light curve parameters. We derived for the first time relatively short periods of the apsidal motion ranging from 21 to 107 years. The system OGLE-LMC-ECL-07902 was also analyzed using the spectra and radial velocities, resulting in masses of 6.8 and 4.4 M{sub ⊙} for the eclipsing components. For one system (OGLE-LMC-ECL-20112), the third-body hypothesis was also used to describe the residuals after subtraction of the apsidal motion, resulting in a period of about 22 years. For several systems an additional third light was also detected, which makes these systems suspect for triplicity.

  17. High precision ray tracing in cylindrically symmetric electrostatics

    Edwards Jr, David, E-mail: dej122842@gmail.com

    2015-11-15

    Highlights: • High precision ray tracing is formulated using power series techniques. • Ray tracing is possible for fields generated by solution to laplace's equation. • Spatial and temporal orders of 4–10 are included. • Precisions in test geometries of hemispherical deflector analyzer of ∼10{sup −20} have been obtained. • This solution offers a considerable extension to the ray tracing accuracy over the current state of art. - Abstract: With the recent availability of a high order FDM solution to the curved boundary value problem, it is now possible to determine potentials in such geometries with considerably greater accuracy than had been available with the FDM method. In order for the algorithms used in the accurate potential calculations to be useful in ray tracing, an integration of those algorithms needs to be placed into the ray trace process itself. The object of this paper is to incorporate these algorithms into a solution of the equations of motion of the ray and, having done this, to demonstrate its efficacy. The algorithm incorporation has been accomplished by using power series techniques and the solution constructed has been tested by tracing the medial ray through concentric sphere geometries. The testing has indicated that precisions of ray calculations of 10{sup −20} are now possible. This solution offers a considerable extension to the ray tracing accuracy over the current state of art.

  18. ELECTROMAGNETIC EMISSION FROM LONG-LIVED BINARY NEUTRON STAR MERGER REMNANTS. II. LIGHT CURVES AND SPECTRA

    Siegel, Daniel M. [Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg 1, D-14476 Potsdam-Golm (Germany); Ciolfi, Riccardo, E-mail: daniel.siegel@aei.mpg.de, E-mail: riccardo.ciolfi@unitn.it [Physics Department, University of Trento, Via Sommarive 14, I-38123 Trento (Italy)

    2016-03-01

    Recent observations indicate that in a large fraction of binary neutron star (BNS) mergers a long-lived neutron star (NS) may be formed rather than a black hole. Unambiguous electromagnetic (EM) signatures of such a scenario would strongly impact our knowledge on how short gamma-ray bursts (SGRBs) and their afterglow radiation are generated. Furthermore, such EM signals would have profound implications for multimessenger astronomy with joint EM and gravitational-wave (GW) observations of BNS mergers, which will soon become reality thanks to the ground-based advanced LIGO/Virgo GW detector network. Here we explore such EM signatures based on the model presented in a companion paper, which provides a self-consistent evolution of the post-merger system and its EM emission up to ∼10{sup 7} s. Light curves and spectra are computed for a wide range of post-merger physical properties. We present X-ray afterglow light curves corresponding to the “standard” and the “time-reversal” scenario for SGRBs (prompt emission associated with the merger or with the collapse of the long-lived NS). The light curve morphologies include single and two-plateau features with timescales and luminosities that are in good agreement with Swift observations. Furthermore, we compute the X-ray signal that should precede the SGRB in the time-reversal scenario, the detection of which would represent smoking-gun evidence for this scenario. Finally, we find a bright, highly isotropic EM transient peaking in the X-ray band at ∼10{sup 2}–10{sup 4} s after the BNS merger with luminosities of L{sub X} ∼ 10{sup 46}–10{sup 48} erg s{sup −1}. This signal represents a very promising EM counterpart to the GW emission from BNS mergers.

  19. A GLOBAL MODEL OF THE LIGHT CURVES AND EXPANSION VELOCITIES OF TYPE II-PLATEAU SUPERNOVAE

    Pejcha, Ondřej [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08540 (United States); Prieto, Jose L., E-mail: pejcha@astro.princeton.edu [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441 Santiago (Chile)

    2015-02-01

    We present a new self-consistent and versatile method that derives photospheric radius and temperature variations of Type II-Plateau supernovae based on their expansion velocities and photometric measurements. We apply the method to a sample of 26 well-observed, nearby supernovae with published light curves and velocities. We simultaneously fit ∼230 velocity and ∼6800 mag measurements distributed over 21 photometric passbands spanning wavelengths from 0.19 to 2.2 μm. The light-curve differences among the Type II-Plateau supernovae are well modeled by assuming different rates of photospheric radius expansion, which we explain as different density profiles of the ejecta, and we argue that steeper density profiles result in flatter plateaus, if everything else remains unchanged. The steep luminosity decline of Type II-Linear supernovae is due to fast evolution of the photospheric temperature, which we verify with a successful fit of SN 1980K. Eliminating the need for theoretical supernova atmosphere models, we obtain self-consistent relative distances, reddenings, and nickel masses fully accounting for all internal model uncertainties and covariances. We use our global fit to estimate the time evolution of any missing band tailored specifically for each supernova, and we construct spectral energy distributions and bolometric light curves. We produce bolometric corrections for all filter combinations in our sample. We compare our model to the theoretical dilution factors and find good agreement for the B and V filters. Our results differ from the theory when the I, J, H, or K bands are included. We investigate the reddening law toward our supernovae and find reasonable agreement with standard R{sub V}∼3.1 reddening law in UBVRI bands. Results for other bands are inconclusive. We make our fitting code publicly available.

  20. SiFTO: An Empirical Method for Fitting SN Ia Light Curves

    Conley, A.; Sullivan, M.; Hsiao, E. Y.; Guy, J.; Astier, P.; Balam, D.; Balland, C.; Basa, S.; Carlberg, R. G.; Fouchez, D.; Hardin, D.; Howell, D. A.; Hook, I. M.; Pain, R.; Perrett, K.; Pritchet, C. J.; Regnault, N.

    2008-07-01

    We present SiFTO, a new empirical method for modeling Type Ia supernova (SN Ia) light curves by manipulating a spectral template. We make use of high-redshift SN data when training the model, allowing us to extend it bluer than rest-frame U. This increases the utility of our high-redshift SN observations by allowing us to use more of the available data. We find that when the shape of the light curve is described using a stretch prescription, applying the same stretch at all wavelengths is not an adequate description. SiFTO therefore uses a generalization of stretch which applies different stretch factors as a function of both the wavelength of the observed filter and the stretch in the rest-frame B band. We compare SiFTO to other published light-curve models by applying them to the same set of SN photometry, and demonstrate that SiFTO and SALT2 perform better than the alternatives when judged by the scatter around the best-fit luminosity distance relationship. We further demonstrate that when SiFTO and SALT2 are trained on the same data set the cosmological results agree. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS.

  1. Type II Supernova Light Curves and Spectra from the CfA

    Hicken, Malcolm; Friedman, Andrew S.; Blondin, Stephane; Challis, Peter; Berlind, Perry; Calkins, Mike; Esquerdo, Gil; Matheson, Thomas; Modjaz, Maryam; Rest, Armin; Kirshner, Robert P.

    2017-11-01

    We present multiband photometry of 60 spectroscopically confirmed supernovae (SNe): 39 SNe II/IIP, 19 IIn, 1 IIb, and 1 that was originally classified as a IIn but later as a Ibn. Of these, 46 have only optical photometry, 6 have only near-infrared (NIR) photometry, and 8 have both optical and NIR. The median redshift of the sample is 0.016. We also present 195 optical spectra for 48 of the 60 SN. There are 26 optical and 2 NIR light curves of SNe II/IIP with redshifts z> 0.01, some of which may give rise to useful distances for cosmological applications. All photometry was obtained between 2000 and 2011 at the Fred Lawrence Whipple Observatory (FLWO), via the 1.2 m and 1.3 m PAIRITEL telescopes for the optical and NIR, respectively. Each SN was observed in a subset of the u\\prime {UBVRIr}\\prime I\\prime {{JHK}}s bands. There are a total of 2932 optical and 816 NIR light curve points. Optical spectra were obtained using the FLWO 1.5 m Tillinghast telescope with the FAST spectrograph and the MMT Telescope with the Blue Channel Spectrograph. Our photometry is in reasonable agreement with select samples from the literature: two-thirds of our star sequences have average V offsets within ±0.02 mag and roughly three-quarters of our light curves have average differences within ±0.04 mag. The data from this work and the literature will provide insight into SN II explosions, help with developing methods for photometric SN classification, and contribute to their use as cosmological distance indicators.

  2. Probing Millisecond Pulsar Emission Geometry Using Light Curves From the Fermi Large Area Telescope

    Venter, Christo; Harding, Alice; Guillemot, L.

    2009-01-01

    An interesting new high-energy pulsar sub-population is emerging following early discoveries of gamma-ray millisecond pulsars (MSPs) by the Fermi Large Area Telescope (LAT). We present results from 3D emission modeling, including the Special Relativistic effects of aberration and time-of-flight delays and also rotational sweepback of 13-field lines, in the geometric context of polar cap (PC), slot gap (SG), outer gap (OG), and two-pole caustic (TPC) pulsar models. In contrast to the general belief that these very old, rapidly-rotating neutron stars (NSs) should have largely pair-starved magnetospheres due to the absence of significant pair production, we find that most of the light curves are best fit by SG and OG models, which indicates the presence of narrow accelerating gaps limited by robust pair production -- even in these pulsars with very low spin-down luminosities. The gamma-ray pulse shapes and relative phase lags with respect to the radio pulses point to high-altitude emission being dominant for all geometries. We also find exclusive differentiation of the current gamma-ray MSP population into two MSP sub-classes: light curve shapes and lags across wavebands impose either pair-starved PC (PSPC) or SG / OG-type geometries. In the first case, the radio pulse has a small lag with respect to the single gamma-ray pulse, while the (first) gamma-ray peak usually trails the radio by a large phase offset in the latter case. Finally, we find that the flux correction factor as a function of magnetic inclination and observer angles is typically of order unity for all models. Our calculation of light curves and flux correction factor f(_, _, P) for the case of MSPs is therefore complementary to the "ATLAS paper" of Watters et al. for younger pulsars.

  3. IMPROVED DARK ENERGY CONSTRAINTS FROM ∼100 NEW CfA SUPERNOVA TYPE Ia LIGHT CURVES

    Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Wood-Vasey, W. Michael; Blondin, Stephane; Jha, Saurabh; Kelly, Patrick L.; Rest, Armin

    2009-01-01

    We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the Constitution set and, combined with a BAO prior, produces 1 + w = 0.013 +0.066 -0.068 (0.11 syst), consistent with the cosmological constant. The CfA3 addition makes the cosmologically useful sample of nearby SN Ia between 2.6 and 2.9 times larger than before, reducing the statistical uncertainty to the point where systematics play the largest role. We use four light-curve fitters to test for systematic differences: SALT, SALT2, MLCS2k2 (R V = 3.1), and MLCS2k2 (R V = 1.7). SALT produces high-redshift Hubble residuals with systematic trends versus color and larger scatter than MLCS2k2. MLCS2k2 overestimates the intrinsic luminosity of SN Ia with 0.7 V = 3.1 overestimates host-galaxy extinction while R V ∼ 1.7 does not. Our investigation is consistent with no Hubble bubble. We also find that, after light-curve correction, SN Ia in Scd/Sd/Irr hosts are intrinsically fainter than those in E/S0 hosts by 2σ, suggesting that they may come from different populations. We also find that SN Ia in Scd/Sd/Irr hosts have low scatter (0.1 mag) and reddening. Current systematic errors can be reduced by improving SN Ia photometric accuracy, by including the CfA3 sample to retrain light-curve fitters, by combining optical SN Ia photometry with near-infrared photometry to understand host-galaxy extinction, and by determining if different environments give rise to different intrinsic SN Ia luminosity after correction for light-curve shape and color.

  4. VizieR Online Data Catalog: Lick AGN monitoring 2011: light curves (Barth+, 2015)

    Barth, A. J.; Bennert, V. N.; Canalizo, G.; Filippenko, A. V.; Gates, E. L.; Greene, J. E.; Li, W.; Malkan, M. A.; Pancoast, A.; Sand, D. J.; Stern, D.; Treu, T.; Woo, J.-H.; Assef, R. J.; Bae, H.-J.; Brewer, B. J.; Cenko, S. B.; Clubb, K. I.; Cooper, M. C.; Diamond-Stanic, A. M.; Hiner, K. D.; Honig, S. F.; Hsiao, E.; Kandrashoff, M. T.; Lazarova, M. S.; Nierenberg, A. M.; Rex, J.; Silverman, J. M.; Tollerud, E. J.; Walsh, J. L.

    2015-05-01

    This project was allocated 69 nights at the Lick 3m Shane telescope, distributed between 2011 March 27 and June 13. Observations were conducted using the Kast double spectrograph (3440-5515Å on the blue side and 5410-8200Å on the red side). In order to extend our light curves for two AGNs, we also requested additional observations from other observers using the Kast spectrograph: Mrk 50 from 2011 January through March, and Zw 229-015 in June and July. For Zw 229-015, three additional observations were taken 20-23 days after the end of our main campaign. See section 3. (2 data files).

  5. THE FIRST SYSTEMATIC STUDY OF TYPE Ibc SUPERNOVA MULTI-BAND LIGHT CURVES

    Drout, Maria R.; Soderberg, Alicia M.; Gal-Yam, Avishay; Arcavi, Iair; Green, Yoav; Cenko, S. Bradley; Fox, Derek B.; Leonard, Douglas C.; Sand, David J.; Moon, Dae-Sik

    2011-01-01

    We present detailed optical photometry for 25 Type Ibc supernovae (SNe Ibc) within d ≈ 150 Mpc obtained with the robotic Palomar 60 inch telescope in 2004-2007. This study represents the first uniform, systematic, and statistical sample of multi-band SNe Ibc light curves available to date. We correct the light curves for host galaxy extinction using a new technique based on the photometric color evolution, namely, we show that the (V – R) color of extinction-corrected SNe Ibc at Δt ≈ 10 days after V-band maximum is tightly distributed, ((V – R) V10 ) = 0.26 ± 0.06 mag. Using this technique, we find that SNe Ibc typically suffer from significant host galaxy extinction, (E(B – V)) ≈ 0.4 mag. A comparison of the extinction-corrected light curves for helium-rich (Type Ib) and helium-poor (Type Ic) SNe reveals that they are statistically indistinguishable, both in luminosity and decline rate. We report peak absolute magnitudes of (M R ) = –17.9 ± 0.9 mag and (M R ) = –18.3 ± 0.6 mag for SNe Ib and Ic, respectively. Focusing on the broad-lined (BL) SNe Ic, we find that they are more luminous than the normal SNe Ibc sample, (M R ) = –19.0 ± 1.1 mag, with a probability of only 1.6% that they are drawn from the same population of explosions. By comparing the peak absolute magnitudes of SNe Ic-BL with those inferred for local engine-driven explosions (GRB-SN 1998bw, XRF-SN 2006aj, and SN 2009bb) we find a 25% probability that relativistic SNe are drawn from the overall SNe Ic-BL population. Finally, we fit analytic models to the light curves to derive typical 56 Ni masses of M Ni ≈ 0.2 and 0.5 M ☉ for SNe Ibc and SNe Ic-BL, respectively. With reasonable assumptions for the photospheric velocities, we further extract kinetic energy and ejecta mass values of M ej ≈ 2 M ☉ and E K ≈ 10 51 erg for SNe Ibc, while for SNe Ic-BL we find higher values, M ej ≈ 5 M ☉ and E K ≈ 10 52 erg. We discuss the implications for the progenitors of SNe Ibc

  6. Emergence of curved light-cones in a class of inhomogeneous Luttinger liquids

    Jérôme Dubail, Jean-Marie Stéphan, Pasquale Calabrese

    2017-09-01

    Full Text Available The light-cone spreading of entanglement and correlation is a fundamental and ubiquitous feature of homogeneous extended quantum systems. Here we point out that a class of inhomogenous Luttinger liquids (those with a uniform Luttinger parameter $K$ at low energy display the universal phenomenon of curved light cones: gapless excitations propagate along the geodesics of the metric $ds^2=dx^2+v(x^2 d\\tau^2$, with $v(x$ being the calculable spatial dependent velocity induced by the inhomogeneity. We confirm our findings with explicit analytic and numerical calculations both in- and out-of-equilibrium for a Tonks-Girardeau gas in a harmonic potential and in lattice systems with artificially tuned hamiltonian density.

  7. A UNIFORM SEARCH FOR SECONDARY ECLIPSES OF HOT JUPITERS IN KEPLER Q2 LIGHT CURVES

    Coughlin, J. L.; López-Morales, M.

    2012-01-01

    In this paper, we present the results of searching the Kepler Q2 public data set for the secondary eclipses of 76 hot Jupiter planet candidates from the list of 1235 candidates published by Borucki et al. This search has been performed by modeling both the Kepler pre-search data conditioned light curves and new light curves produced via our own photometric pipeline. We derive new stellar and planetary parameters for each system, while calculating robust errors for both. We find 16 systems with 1σ-2σ, 14 systems with 2σ-3σ, and 6 systems with >3σ confidence level secondary eclipse detections in at least one light curve produced via the Kepler pre-search data conditioned light curve or our own pipeline; however, results can vary depending on the light curve modeled and whether eccentricity is allowed to vary or not. We estimate false alarm probabilities of 31%, 10%, and 6% for the 1σ-2σ, 2σ-3σ, and >3σ confidence intervals, respectively. Comparing each secondary eclipse result to theoretical expectations, we find that the majority of detected planet candidates emit more light than expected owing to thermal blackbody emission in the optical Kepler bandpass, and present a trend of increasing excess emission with decreasing maximum effective planetary temperature. These results agree with previously published optical secondary eclipse data for other hot Jupiters. We explore modeling biases, significant planetary albedos, non-local thermodynamic equilibrium or other thermal emission, significant internal energy generation, and misidentification of brown dwarfs, low-mass stars, or stellar blends as possible causes of both the excess emission and its correlation with expected planetary temperature. Although we find that no single cause is able to explain all of the planet candidates, significant planetary albedos, with a general trend of increasing planetary albedos with decreasing atmospheric temperatures, are able to explain most of the systems. Identifying

  8. Detection of Time Lags between Quasar Continuum Emission Bands Based On Pan-STARRS Light Curves

    Jiang, Yan-Fei [Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States); Green, Paul J.; Pancoast, Anna; MacLeod, Chelsea L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Morganson, Eric; Shen, Yue [Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Anderson, Scott F.; Ruan, John J. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Brandt, W. N.; Grier, C. J. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Rix, H.-W. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Protopapas, Pavlos [Institute for Applied Computational Science, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Scott, Caroline [Astrophysics, Imperial College London, Blackett Laboratory, London SW7 2AZ (United Kingdom); Burgett, W. S.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu HI 96822 (United States); and others

    2017-02-20

    We study the time lags between the continuum emission of quasars at different wavelengths, based on more than four years of multi-band ( g , r , i , z ) light curves in the Pan-STARRS Medium Deep Fields. As photons from different bands emerge from different radial ranges in the accretion disk, the lags constrain the sizes of the accretion disks. We select 240 quasars with redshifts of z ≈ 1 or z ≈ 0.3 that are relatively emission-line free. The light curves are sampled from day to month timescales, which makes it possible to detect lags on the scale of the light crossing time of the accretion disks. With the code JAVELIN , we detect typical lags of several days in the rest frame between the g band and the riz bands. The detected lags are ∼2–3 times larger than the light crossing time estimated from the standard thin disk model, consistent with the recently measured lag in NGC 5548 and microlensing measurements of quasars. The lags in our sample are found to increase with increasing luminosity. Furthermore, the increase in lags going from g − r to g − i and then to g − z is slower than predicted in the thin disk model, particularly for high-luminosity quasars. The radial temperature profile in the disk must be different from what is assumed. We also find evidence that the lags decrease with increasing line ratios between ultraviolet Fe ii lines and Mg ii, which may point to changes in the accretion disk structure at higher metallicity.

  9. A unique UV flare in the optical light curve of the quasar J004457.9+412344

    Hatzidimitriou D.

    2012-12-01

    Full Text Available We found that the nova candidate J004457.9+412344 is a radio-quiet quasar at z ∼ 2. Its optical long-term light curve, covering more than half a century, shows quasar typical flux variations superimposed by a spectacular single flare lasting more than one year (observer frame. We could not find comparable light curves among the several thousand catalogued radio-quiet quasars in the stripe 82 of the Sloan Digital Sky Survey. The decreasing part of the flare light curve roughly follows a power law t−5/3. The quasar spectrum, the total energy of the flare, and the decline of the light curve are consistent with the tidal disruption of a ∼10 Mʘ giant star by a supermassive black hole of a few 108 Mʘ. We argue that the alternative explanation by gravitational microlensing is less likely, though it cannot be definitely excluded.

  10. Multi-messenger Light Curves from Gamma-Ray Bursts in the Internal Shock Model

    Bustamante, Mauricio [Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, OH 43210 (United States); Heinze, Jonas; Winter, Walter [Deutsches Elektronen-Synchrotron (DESY), Platanenallee 6, D-15738 Zeuthen (Germany); Murase, Kohta, E-mail: bustamanteramirez.1@osu.edu, E-mail: walter.winter@desy.de, E-mail: jonas.heinze@desy.de, E-mail: murase@psu.edu [Center for Particle and Gravitational Astrophysics, The Pennsylvania State University, University Park, PA16802 (United States)

    2017-03-01

    Gamma-ray bursts (GRBs) are promising as sources of neutrinos and cosmic rays. In the internal shock scenario, blobs of plasma emitted from a central engine collide within a relativistic jet and form shocks, leading to particle acceleration and emission. Motivated by present experimental constraints and sensitivities, we improve the predictions of particle emission by investigating time-dependent effects from multiple shocks. We produce synthetic light curves with different variability timescales that stem from properties of the central engine. For individual GRBs, qualitative conclusions about model parameters, neutrino production efficiency, and delays in high-energy gamma-rays can be deduced from inspection of the gamma-ray light curves. GRBs with fast time variability without additional prominent pulse structure tend to be efficient neutrino emitters, whereas GRBs with fast variability modulated by a broad pulse structure can be inefficient neutrino emitters and produce delayed high-energy gamma-ray signals. Our results can be applied to quantitative tests of the GRB origin of ultra-high-energy cosmic rays, and have the potential to impact current and future multi-messenger searches.

  11. Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves

    Jacob, Rinku; Harikrishnan, K. P.; Misra, R.; Ambika, G.

    2018-01-01

    Recurrence networks and the associated statistical measures have become important tools in the analysis of time series data. In this work, we test how effective the recurrence network measures are in analyzing real world data involving two main types of noise, white noise and colored noise. We use two prominent network measures as discriminating statistic for hypothesis testing using surrogate data for a specific null hypothesis that the data is derived from a linear stochastic process. We show that the characteristic path length is especially efficient as a discriminating measure with the conclusions reasonably accurate even with limited number of data points in the time series. We also highlight an additional advantage of the network approach in identifying the dimensionality of the system underlying the time series through a convergence measure derived from the probability distribution of the local clustering coefficients. As examples of real world data, we use the light curves from a prominent black hole system and show that a combined analysis using three primary network measures can provide vital information regarding the nature of temporal variability of light curves from different spectroscopic classes.

  12. SNaX: A Database of Supernova X-Ray Light Curves

    Ross, Mathias; Dwarkadas, Vikram V., E-mail: Mathias_Ross@msn.com, E-mail: vikram@oddjob.uchicago.edu [Astronomy and Astrophysics, University of Chicago, 5640 S Ellis Avenue, ERC 569, Chicago, IL 60637 (United States)

    2017-06-01

    We present the Supernova X-ray Database (SNaX), a compilation of the X-ray data from young supernovae (SNe). The database includes the X-ray fluxes and luminosities of young SNe, from days to years after outburst. The original goal and intent of this study was to present a database of Type IIn SNe (SNe IIn), which we have accomplished. Our ongoing goal is to expand the database to include all SNe for which published data are available. The database interface allows one to search for SNe using various criteria, plot all or selected data points, and download both the data and the plot. The plotting facility allows for significant customization. There is also a facility for the user to submit data that can be directly incorporated into the database. We include an option to fit the decay of any given SN light curve with a power-law. The database includes a conversion of most data points to a common 0.3–8 keV band so that SN light curves may be directly compared with each other. A mailing list has been set up to disseminate information about the database. We outline the structure and function of the database, describe its various features, and outline the plans for future expansion.

  13. EXTRACTING PERIODIC TRANSIT SIGNALS FROM NOISY LIGHT CURVES USING FOURIER SERIES

    Samsing, Johan [Department of Astrophysical Sciences, Princeton University, Peyton Hall, 4 Ivy Lane, Princeton, NJ 08544 (United States)

    2015-07-01

    We present a simple and powerful method for extracting transit signals associated with a known transiting planet from noisy light curves. Assuming the orbital period of the planet is known and the signal is periodic, we illustrate that systematic noise can be removed in Fourier space at all frequencies by only using data within a fixed time frame with a width equal to an integer number of orbital periods. This results in a reconstruction of the full transit signal, which on average is unbiased despite no prior knowledge of either the noise or the transit signal itself being used in the analysis. The method therefore has clear advantages over standard phase folding, which normally requires external input such as nearby stars or noise models for removing systematic components. In addition, we can extract the full orbital transit signal (360°) simultaneously, and Kepler-like data can be analyzed in just a few seconds. We illustrate the performance of our method by applying it to a dataset composed of light curves from Kepler with a fake injected signal emulating a planet with rings. For extracting periodic transit signals, our presented method is in general the optimal and least biased estimator and could therefore lead the way toward the first detections of, e.g., planet rings and exo-trojan asteroids.

  14. Cosmological parameter uncertainties from SALT-II type Ia supernova light curve models

    Mosher, J.; Sako, M.; Guy, J.; Astier, P.; Betoule, M.; El-Hage, P.; Pain, R.; Regnault, N.; Kessler, R.; Frieman, J. A.; Marriner, J.; Biswas, R.; Kuhlmann, S.; Schneider, D. P.

    2014-01-01

    We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ∼120 low-redshift (z < 0.1) SNe Ia, ∼255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ∼290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w input – w recovered ) ranging from –0.005 ± 0.012 to –0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty; the average bias on w is –0.014 ± 0.007.

  15. THE CARNEGIE SUPERNOVA PROJECT: LIGHT-CURVE FITTING WITH SNooPy

    Burns, Christopher R.; Persson, S. E.; Madore, Barry F.; Freedman, Wendy L.; Stritzinger, Maximilian; Phillips, M. M.; Boldt, Luis; Campillay, Abdo; Folatelli, Gaston; Gonzalez, Sergio; Krzeminski, Wojtek; Morrell, Nidia; Salgado, Francisco; Kattner, ShiAnne; Contreras, Carlos; Suntzeff, Nicholas B.

    2011-01-01

    In providing an independent measure of the expansion history of the universe, the Carnegie Supernova Project (CSP) has observed 71 high-z Type Ia supernovae (SNe Ia) in the near-infrared bands Y and J. These can be used to construct rest-frame i-band light curves which, when compared to a low-z sample, yield distance moduli that are less sensitive to extinction and/or decline-rate corrections than in the optical. However, working with NIR observed and i-band rest-frame photometry presents unique challenges and has necessitated the development of a new set of observational tools in order to reduce and analyze both the low-z and high-z CSP sample. We present in this paper the methods used to generate uBVgriYJH light-curve templates based on a sample of 24 high-quality low-z CSP SNe. We also present two methods for determining the distances to the hosts of SN Ia events. A larger sample of 30 low-z SNe Ia in the Hubble flow is used to calibrate these methods. We then apply the method and derive distances to seven galaxies that are so nearby that their motions are not dominated by the Hubble flow.

  16. The Origin and Evolution of the Infrared Light Curve of SN2010jl

    Dwek, Eli; Sarangi, Arkaprabha; Arendt, Richard; Fox, Ori; Kallman, Timothy; Kazanas, Demosthenes

    2018-01-01

    SN2010jl is a luminous core-collapse supernova (CCSN) of Type IIn that is surrounded by a dense circumstellar medium (CSM). The supernova (SN) luminosity vastly exceeds the available power from radiactive elements in the ejecta, and is powered by the interaction of the SN shock wave with the ambient medium. Upper limits on the UV and near-IR (NIR) emission from pre-explosion images of the region suggest that any progenitor star was hidden by pre-existing CSM dust. After day ~80, the SN spectrum shows the development of an IR excess above the extrapolated UVO emission arising from the shocked CSM. This IR component is attributed to thermal emission from dust.After day ~300, the light curve exhibits a rise in the NIR luminosity, concurrent with a steep decline at UVO wavelengths. Ruling out any possible contribution of SN-condensed dust to the IR light curve, we show that the early IR emission arises from the pre-existing CSM dust that survived the flash of radiation from the shock breakout. The late IR emission arises from newly-formed CSM dust that condensed in the cooling dust-free postshock gas of the advancing SN shock wave. Our analysis presents the first detailed modeling of dust formation in a cooling postshock environment, and provides important insights into the interaction of the SN shock wave with the CSM.

  17. PERIOD ESTIMATION FOR SPARSELY SAMPLED QUASI-PERIODIC LIGHT CURVES APPLIED TO MIRAS

    He, Shiyuan; Huang, Jianhua Z.; Long, James [Department of Statistics, Texas A and M University, College Station, TX (United States); Yuan, Wenlong; Macri, Lucas M., E-mail: lmacri@tamu.edu [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX (United States)

    2016-12-01

    We develop a nonlinear semi-parametric Gaussian process model to estimate periods of Miras with sparsely sampled light curves. The model uses a sinusoidal basis for the periodic variation and a Gaussian process for the stochastic changes. We use maximum likelihood to estimate the period and the parameters of the Gaussian process, while integrating out the effects of other nuisance parameters in the model with respect to a suitable prior distribution obtained from earlier studies. Since the likelihood is highly multimodal for period, we implement a hybrid method that applies the quasi-Newton algorithm for Gaussian process parameters and search the period/frequency parameter space over a dense grid. A large-scale, high-fidelity simulation is conducted to mimic the sampling quality of Mira light curves obtained by the M33 Synoptic Stellar Survey. The simulated data set is publicly available and can serve as a testbed for future evaluation of different period estimation methods. The semi-parametric model outperforms an existing algorithm on this simulated test data set as measured by period recovery rate and quality of the resulting period–luminosity relations.

  18. Multi-messenger light curves from gamma-ray bursts in the internal shock model

    Bustamante, Mauricio [Ohio State Univ., Columbus, OH (United States). Center for Cosmology and AstroParticle Physics (CCAPP); Ohio State Univ., Columbus, OH (United States). Dept. of Physics; Murase, Kohta [Pennsylvania State Univ., University Park, PA (United States). Center for Particle and Gravitational Astrophysics; Pennsylvania State Univ., University Park, PA (United States). Dept. of Astronomy and Astrophysics; Winter, Walter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2016-06-15

    Gamma-ray bursts (GRBs) are promising as sources of neutrinos and cosmic rays. In the internal shock scenario, blobs of plasma emitted from a central engine collide within a relativistic jet and form shocks, leading to particle acceleration and emission. Motivated by present experimental constraints and sensitivities, we improve the predictions of particle emission by investigating time-dependent effects from multiple shocks. We produce synthetic light curves with different variability timescales that stem from properties of the central engine. For individual GRBs, qualitative conclusions about model parameters, neutrino production efficiency, and delays in high-energy gamma rays can be deduced from inspection of the gamma-ray light curves. GRBs with fast time variability without additional prominent pulse structure tend to be efficient neutrino emitters, whereas GRBs with fast variability modulated by a broad pulse structure tend to be inefficient neutrino emitters and produce delayed high-energy gamma-ray signals. Our results can be applied to quantitative tests of the GRB origin of ultra-high-energy cosmic rays, and have the potential to impact current and future multi-messenger searches.

  19. SNaX: A Database of Supernova X-Ray Light Curves

    Ross, Mathias; Dwarkadas, Vikram V.

    2017-01-01

    We present the Supernova X-ray Database (SNaX), a compilation of the X-ray data from young supernovae (SNe). The database includes the X-ray fluxes and luminosities of young SNe, from days to years after outburst. The original goal and intent of this study was to present a database of Type IIn SNe (SNe IIn), which we have accomplished. Our ongoing goal is to expand the database to include all SNe for which published data are available. The database interface allows one to search for SNe using various criteria, plot all or selected data points, and download both the data and the plot. The plotting facility allows for significant customization. There is also a facility for the user to submit data that can be directly incorporated into the database. We include an option to fit the decay of any given SN light curve with a power-law. The database includes a conversion of most data points to a common 0.3–8 keV band so that SN light curves may be directly compared with each other. A mailing list has been set up to disseminate information about the database. We outline the structure and function of the database, describe its various features, and outline the plans for future expansion.

  20. Cosmological Parameter Uncertainties from SALT-II Type Ia Supernova Light Curve Models

    Mosher, J. [Pennsylvania U.; Guy, J. [LBL, Berkeley; Kessler, R. [Chicago U., KICP; Astier, P. [Paris U., VI-VII; Marriner, J. [Fermilab; Betoule, M. [Paris U., VI-VII; Sako, M. [Pennsylvania U.; El-Hage, P. [Paris U., VI-VII; Biswas, R. [Argonne; Pain, R. [Paris U., VI-VII; Kuhlmann, S. [Argonne; Regnault, N. [Paris U., VI-VII; Frieman, J. A. [Fermilab; Schneider, D. P. [Penn State U.

    2014-08-29

    We use simulated type Ia supernova (SN Ia) samples, including both photometry and spectra, to perform the first direct validation of cosmology analysis using the SALT-II light curve model. This validation includes residuals from the light curve training process, systematic biases in SN Ia distance measurements, and a bias on the dark energy equation of state parameter w. Using the SN-analysis package SNANA, we simulate and analyze realistic samples corresponding to the data samples used in the SNLS3 analysis: ~120 low-redshift (z < 0.1) SNe Ia, ~255 Sloan Digital Sky Survey SNe Ia (z < 0.4), and ~290 SNLS SNe Ia (z ≤ 1). To probe systematic uncertainties in detail, we vary the input spectral model, the model of intrinsic scatter, and the smoothing (i.e., regularization) parameters used during the SALT-II model training. Using realistic intrinsic scatter models results in a slight bias in the ultraviolet portion of the trained SALT-II model, and w biases (w (input) – w (recovered)) ranging from –0.005 ± 0.012 to –0.024 ± 0.010. These biases are indistinguishable from each other within the uncertainty, the average bias on w is –0.014 ± 0.007.

  1. KIC 4552982: outbursts and pulsations in the longest-ever pseudo-continuous light curve of a ZZ Ceti

    Bell K. J.

    2015-01-01

    Full Text Available KIC 4552982 was the first ZZ Ceti (hydrogen-atmosphere pulsating white dwarf identified to lie in the Kepler field, resulting in the longest pseudo-continuous light curve ever obtained for this type of variable star. In addition to the pulsations, this light curve exhibits stochastic episodes of brightness enhancement unlike any previously studied white dwarf phenomenon. We briefly highlight the basic outburst and pulsation properties in these proceedings.

  2. Infrared rotational light curves on Jupiter induced by wave activities and cloud patterns andimplications on brown dwarfs

    Ge, Huazhi; Zhang, Xi; Fletcher, Leigh; Orton, Glenn S.; Sinclair, James Andrew; Fernandes,, Joshua; Momary, Thomas W.; Warren, Ari; Kasaba, Yasumasa; Sato, Takao M.; Fujiyoshi, Takuya

    2017-10-01

    Many brown dwarfs exhibit infrared rotational light curves with amplitude varying from a fewpercent to twenty percent (Artigau et al. 2009, ApJ, 701, 1534; Radigan et al. 2012, ApJ, 750,105). Recently, it was claimed that weather patterns, especially planetary-scale waves in thebelts and cloud spots, are responsible for the light curves and their evolutions on brown dwarfs(Apai et al. 2017, Science, 357, 683). Here we present a clear relationship between the direct IRemission maps and light curves of Jupiter at multiple wavelengths, which might be similar withthat on cold brown dwarfs. Based on infrared disk maps from Subaru/COMICS and VLT/VISIR,we constructed full maps of Jupiter and rotational light curves at different wavelengths in thethermal infrared. We discovered a strong relationship between the light curves and weatherpatterns on Jupiter. The light curves also exhibit strong multi-bands phase shifts and temporalvariations, similar to that detected on brown dwarfs. Together with the spectra fromTEXES/IRTF, our observations further provide detailed information of the spatial variations oftemperature, ammonia clouds and aerosols in the troposphere of Jupiter (Fletcher et al. 2016,Icarus, 2016 128) and their influences on the shapes of the light curves. We conclude that waveactivities in Jupiter’s belts (Fletcher et al. 2017, GRL, 44, 7140), cloud holes, and long-livedvortices such as the Great Red Spot and ovals control the shapes of IR light curves and multi-wavelength phase shifts on Jupiter. Our finding supports the hypothesis that observed lightcurves on brown dwarfs are induced by planetary-scale waves and cloud spots.

  3. High precision refractometry based on Fresnel diffraction from phase plates.

    Tavassoly, M Taghi; Naraghi, Roxana Rezvani; Nahal, Arashmid; Hassani, Khosrow

    2012-05-01

    When a transparent plane-parallel plate is illuminated at a boundary region by a monochromatic parallel beam of light, Fresnel diffraction occurs because of the abrupt change in phase imposed by the finite change in refractive index at the plate boundary. The visibility of the diffraction fringes varies periodically with changes in incident angle. The visibility period depends on the plate thickness and the refractive indices of the plate and the surrounding medium. Plotting the phase change versus incident angle or counting the visibility repetition in an incident-angle interval provides, for a given plate thickness, the refractive index of the plate very accurately. It is shown here that the refractive index of a plate can be determined without knowing the plate thickness. Therefore, the technique can be utilized for measuring plate thickness with high precision. In addition, by installing a plate with known refractive index in a rectangular cell filled with a liquid and following the described procedures, the refractive index of the liquid is obtained. The technique is applied to measure the refractive indices of a glass slide, distilled water, and ethanol. The potential and merits of the technique are also discussed.

  4. Wavefronts, light rays and caustic of a circular wave reflected by an arbitrary smooth curve

    Marciano-Melchor, Magdalena; Silva-Ortigoza, Ramón; Montiel-Piña, Enrique; Román-Hernández, Edwin; Santiago-Santiago, José Guadalupe; Silva-Ortigoza, Gilberto; Rosado, Alfonso; Suárez-Xique, Román

    2011-01-01

    The aim of the present work is to obtain expressions for both the wavefront train and the caustic associated with the light rays reflected by an arbitrary smooth curve after being emitted by a point light source located at an arbitrary position in the two-dimensional free space. To this end, we obtain an expression for the k-function associated with the general integral of Stavroudis to the eikonal equation that describes the evolution of the reflected light rays. The caustic is computed by using the definitions of the critical and caustic sets of the two-dimensional map that describes the evolution of an arbitrary wavefront associated with the general integral. The general results are applied to circular and parabolic mirrors. The main motivation to carry out this research is to establish, in future work, the caustic touching theorem in a two-dimensional optical medium and to study the diffraction problem by using the k-function concept. Both problems are important in the computation of the image of an arbitrary object under reflection and refraction

  5. GLOBAL MAPPING OF EARTH-LIKE EXOPLANETS FROM SCATTERED LIGHT CURVES

    Kawahara, Hajime; Fujii, Yuka

    2010-01-01

    Scattered lights from terrestrial exoplanets provide valuable information about their planetary surface. Applying the surface reconstruction method proposed by Fujii et al. to both diurnal and annual variations of scattered light, we develop a reconstruction method of land distribution with both longitudinal and latitudinal resolutions. We find that one can recover a global map of an idealized Earth-like planet on the following assumptions: (1) cloudlessness, (2) a face-on circular orbit, (3) known surface types and their reflectance spectra, (4) lack of atmospheric absorption, (5) known rotation rate, (6) a static map, and (7) the absence of a moon. Using the dependence of light curves on planetary obliquity, we also show that the obliquity can be measured by adopting the χ 2 minimization or the extended information criterion. We demonstrate the feasibility of our methodology by applying it to a multi-band photometry of a cloudless model Earth with future space missions such as the occulting ozone observatory (O3). We conclude that future space missions can estimate both the surface distribution and the obliquity at least for cloudless Earth-like planets within 5 pc.

  6. The EB factory project. I. A fast, neural-net-based, general purpose light curve classifier optimized for eclipsing binaries

    Paegert, Martin; Stassun, Keivan G.; Burger, Dan M.

    2014-01-01

    We describe a new neural-net-based light curve classifier and provide it with documentation as a ready-to-use tool for the community. While optimized for identification and classification of eclipsing binary stars, the classifier is general purpose, and has been developed for speed in the context of upcoming massive surveys such as the Large Synoptic Survey Telescope. A challenge for classifiers in the context of neural-net training and massive data sets is to minimize the number of parameters required to describe each light curve. We show that a simple and fast geometric representation that encodes the overall light curve shape, together with a chi-square parameter to capture higher-order morphology information results in efficient yet robust light curve classification, especially for eclipsing binaries. Testing the classifier on the ASAS light curve database, we achieve a retrieval rate of 98% and a false-positive rate of 2% for eclipsing binaries. We achieve similarly high retrieval rates for most other periodic variable-star classes, including RR Lyrae, Mira, and delta Scuti. However, the classifier currently has difficulty discriminating between different sub-classes of eclipsing binaries, and suffers a relatively low (∼60%) retrieval rate for multi-mode delta Cepheid stars. We find that it is imperative to train the classifier's neural network with exemplars that include the full range of light curve quality to which the classifier will be expected to perform; the classifier performs well on noisy light curves only when trained with noisy exemplars. The classifier source code, ancillary programs, a trained neural net, and a guide for use, are provided.

  7. The host galaxy and optical light curve of the gamma-ray burst GRB 980703

    Holland, S.; Fynbo, J.P.U.; Hjorth, J.

    2001-01-01

    We present deep HST/STIS and ground-based photometry of the host galaxy of the gamma-ray burst GRB 980703 taken 17, 551, 710, and 716 days after the burst. We find that the host is a blue, slightly over-luminous galaxy with V-gal = 23.00 +/-0.10, (V - R)(gal) = 0.43 +/-0.13, and a centre...... 980703 with any special features in the host. The host galaxy appears to be a typical example of a compact star forming galaxy similar to those found in the Hubble Deep Field North. The R-band light curve of the optical afterglow associated with this gamma-ray burst is consistent with a single power...

  8. Observations and light curve solutions of four ultrashort-period binaries

    Kjurkchieva D.

    2016-01-01

    Full Text Available The paper presents light curve solutions of our observations of four new ultrashort-period eclipsing binaries with MS components. Two of them have periods almost at the upper limit (0.22 days of the ultrashort-period binaries, while the periods of around 0.18 days of CSS J171508.5+350658 and CSS J214633.8+120016 are amongst the shortest known orbital periods. CSS J171410.0+ 445850, CSS J214633.8+120016 and CSS J224326.0+154532 are over contact binaries with fill out factors around 0.25 while CSS J171508.5+350658 is a semidetached system. The two targets with shortest periods consist of M dwarfs.

  9. QUEST1 Variability Survey. II. Variability Determination Criteria and 200k Light Curve Catalog

    Rengstorf, A. W.; Mufson, S. L.; Andrews, P.; Honeycutt, R. K.; Vivas, A. K.; Abad, C.; Adams, B.; Bailyn, C.; Baltay, C.; Bongiovanni, A.; Briceño, C.; Bruzual, G.; Coppi, P.; Della Prugna, F.; Emmet, W.; Ferrín, I.; Fuenmayor, F.; Gebhard, M.; Hernández, J.; Magris, G.; Musser, J.; Naranjo, O.; Oemler, A.; Rosenzweig, P.; Sabbey, C. N.; Sánchez, Ge.; Sánchez, Gu.; Schaefer, B.; Schenner, H.; Sinnott, J.; Snyder, J. A.; Sofia, S.; Stock, J.; van Altena, W.

    2004-12-01

    The QUEST (QUasar Equatorial Survey Team) Phase 1 camera has collected multibandpass photometry on a large strip of high Galactic latitude sky over a period of 26 months. This robust data set has been reduced and nightly catalogs compared to determine the photometric variability of the ensemble objects. Subsequent spectroscopic observations have confirmed a subset of the photometric variables as quasars, as previously reported. This paper reports on the details of the data reduction and analysis pipeline and presents multiple bandpass light curves for 198,213 QUEST1 objects, along with global variability information and matched Sloan photometry. Based on observations obtained at the Llano del Hato National Astronomical Observatory, operated by the Centro de Investigaciones de Astronomía for the Ministerio de Ciencia y Tecnologia of Venezuela.

  10. Light-Curve Modelling Constraints on the Obliquities and Aspect Angles of the Young Fermi Pulsars

    Pierbattista, M.; Harding, A. K.; Grenier, I. A.; Johnson, T. J.; Caraveo, P. A.; Kerr, M.; Gonthier, P. L.

    2015-01-01

    In more than four years of observation the Large Area Telescope on board the Fermi satellite has identified pulsed gamma-ray emission from more than 80 young or middle-aged pulsars, in most cases providing light curves with high statistics. Fitting the observed profiles with geometrical models can provide estimates of the magnetic obliquity alpha and of the line of sight angle zeta, yielding estimates of the radiation beaming factor and radiated luminosity. Using different gamma-ray emission geometries (Polar Cap, Slot Gap, Outer Gap, One Pole Caustic) and core plus cone geometries for the radio emission, we fit gamma-ray light curves for 76 young or middle-aged pulsars and we jointly fit their gamma-ray plus radio light curves when possible. We find that a joint radio plus gamma-ray fit strategy is important to obtain (alpha, zeta) estimates that can explain simultaneously detectable radio and gamma-ray emission: when the radio emission is available, the inclusion of the radio light curve in the fit leads to important changes in the (alpha, gamma) solutions. The most pronounced changes are observed for Outer Gap and One Pole Caustic models for which the gamma-ray only fit leads to underestimated alpha or zeta when the solution is found to the left or to the right of the main alpha-zeta plane diagonal respectively. The intermediate-to-high altitude magnetosphere models, Slot Gap, Outer Gap, and One pole Caustic, are favored in explaining the observations. We find no apparent evolution of a on a time scale of 106 years. For all emission geometries our derived gamma-ray beaming factors are generally less than one and do not significantly evolve with the spin-down power. A more pronounced beaming factor vs. spin-down power correlation is observed for Slot Gap model and radio-quiet pulsars and for the Outer Gap model and radio-loud pulsars. The beaming factor distributions exhibit a large dispersion that is less pronounced for the Slot Gap case and that decreases from

  11. CHANDRA OBSERVATIONS OF SN 1987A: THE SOFT X-RAY LIGHT CURVE REVISITED

    Helder, E. A.; Broos, P. S.; Burrows, D. N. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Dewey, D. [MIT Kavli Institute, Cambridge, MA 02139 (United States); Dwek, E. [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); McCray, R. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Park, S. [Department of Physics, University of Texas at Arlington, Box 19059, Arlington, TX 76019 (United States); Racusin, J. L. [NASA, Goddard Space Flight Center, Code 661, Greenbelt, MD 20771 (United States); Zhekov, S. A. [Space Research and Technology Institute, Akad. G. Bonchev str., bl.1, Sofia 1113 (Bulgaria)

    2013-02-10

    We report on the present stage of SN 1987A as observed by the Chandra X-Ray Observatory. We reanalyze published Chandra observations and add three more epochs of Chandra data to get a consistent picture of the evolution of the X-ray fluxes in several energy bands. We discuss the implications of several calibration issues for Chandra data. Using the most recent Chandra calibration files, we find that the 0.5-2.0 keV band fluxes of SN 1987A have increased by {approx}6 Multiplication-Sign 10{sup -13} erg s{sup -1} cm{sup -2} per year since 2009. This is in contrast with our previous result that the 0.5-2.0 keV light curve showed a sudden flattening in 2009. Based on our new analysis, we conclude that the forward shock is still in full interaction with the equatorial ring.

  12. Finite source sizes and the information content of macho-type lens search light curves

    Nemiroff, Robert J.; Wickramasinghe, W. A. D. T.

    1994-01-01

    If the dark halo matter is primarily composed of Massive Compact Halo Objects (MACHOs) toward the lower end of the possible detection range (less than 10(exp -3) solar mass) a fraction of the lens detection events should involve the lens crossing directly in front of the disk of the background star. Previously, Nemiroff has shown that each crossing would create an inflection point in the light curve of the MACHO event. Such inflection points would allow a measure of the time it took for the lens to cross the stellar disk. Given an independent estimate of the stellar radius by other methods, one could then obtain a more accurate estimate of the velocity of the lens. This velocity could then, in turn, be used to obtain a more accurate estimate of the mass range for the MACHO or disk star doing the lensing.

  13. Ultraviolet Light Curves of Gaia16apd in Superluminous Supernova Models

    Tolstov, Alexey; Zhiglo, Andrey; Nomoto, Ken’ichi; Blinnikov, Sergei [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Sorokina, Elena [Sternberg Astronomical Institute, M.V.Lomonosov Moscow State University, 119234 Moscow (Russian Federation); Kozyreva, Alexandra, E-mail: alexey.tolstov@ipmu.jp [The Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

    2017-08-10

    Observations of Gaia16apd revealed extremely luminous ultraviolet emission among superluminous supernovae (SLSNe). Using radiation hydrodynamics simulations, we perform a comparison of UV light curves, color temperatures, and photospheric velocities between the most popular SLSN models: pair-instability supernova, magnetar, and interaction with circumstellar medium. We find that the interaction model is the most promising to explain the extreme UV luminosity of Gaia16apd. The differences in late-time UV emission and in color evolution found between the models can be used to link an observed SLSN event to the most appropriate model. Observations at UV wavelengths can be used to clarify the nature of SLSNe and more attention should be paid to them in future follow-up observations.

  14. A posteriori noise estimation in variable data sets. With applications to spectra and light curves

    Czesla, S.; Molle, T.; Schmitt, J. H. M. M.

    2018-01-01

    Most physical data sets contain a stochastic contribution produced by measurement noise or other random sources along with the signal. Usually, neither the signal nor the noise are accurately known prior to the measurement so that both have to be estimated a posteriori. We have studied a procedure to estimate the standard deviation of the stochastic contribution assuming normality and independence, requiring a sufficiently well-sampled data set to yield reliable results. This procedure is based on estimating the standard deviation in a sample of weighted sums of arbitrarily sampled data points and is identical to the so-called DER_SNR algorithm for specific parameter settings. To demonstrate the applicability of our procedure, we present applications to synthetic data, high-resolution spectra, and a large sample of space-based light curves and, finally, give guidelines to apply the procedure in situation not explicitly considered here to promote its adoption in data analysis.

  15. An information preserving method for producing full coverage CoRoT light curves

    Pascual-Granado J.

    2015-01-01

    Full Text Available Invalid flux measurements, caused mainly by the South Atlantic Anomaly crossing of the CoRoT satellite, introduce aliases in the periodogram and wrong amplitudes. It has been demonstrated that replacing such invalid data with a linear interpolation is not harmless. On the other side, using power spectrum estimators for unevenly sampled time series is not only less computationally efficient but it leads to difficulties in the interpretation of the results. Therefore, even when the gaps are rather small and the duty cycle is high enough the use of gap-filling methods is a gain in frequency analysis. However, the method must preserve the information contained in the time series. In this work we give a short description of an information preserving method (MIARMA and show some results when applying it to CoRoT seismo light curves. The method is implemented as the second step of a pipeline for CoRoT data analysis.

  16. Spectral analysis of stellar light curves by means of neural networks

    Tagliaferri, R.; Ciaramella, A.; Milano, L.; Barone, F.; Longo, G.

    1999-06-01

    Periodicity analysis of unevenly collected data is a relevant issue in several scientific fields. In astrophysics, for example, we have to find the fundamental period of light or radial velocity curves which are unevenly sampled observations of stars. Classical spectral analysis methods are unsatisfactory to solve the problem. In this paper we present a neural network based estimator system which performs well the frequency extraction in unevenly sampled signals. It uses an unsupervised Hebbian nonlinear neural algorithm to extract, from the interpolated signal, the principal components which, in turn, are used by the MUSIC frequency estimator algorithm to extract the frequencies. The neural network is tolerant to noise and works well also with few points in the sequence. We benchmark the system on synthetic and real signals with the Periodogram and with the Cramer-Rao lower bound. This work was been partially supported by IIASS, by MURST 40\\% and by the Italian Space Agency.

  17. A Study of Precataclysmic Binaries Through Theoretic Modeling of Light Curves and Spectra

    Mitrofanova, A. A.; Shimansky, V. V.; Borisov, N. V.

    2017-06-01

    The article presents results of three pre-cataclysmic binaries (PN G068.1+11.0, TW Crv and RE J2013+4002) investigation. Spectroscopic and photometric observations were obtained on BTA and Zeiss-1000 of SAO RAS and on RTT-150. We used the modeling of light curves and spectra to determine the fundamental parameters for all three systems. The PN G068.1+11.0 parameters were obtained with the use of the evolutionary tracks for the nuclei of planetary nebulae of different masses. According to the results of the study, it was found that the secondary components of PN G068.1+11.0 and TW Crv have luminosity excess, but secondary component of RE J2013+4002 doesn't have one.

  18. Periods and light curves of 16 Cepheid variables in IC 1613 not completed by Baade

    Carlson, G.; Sandage, A.

    1990-01-01

    New periods and light curves are presented for 16 of the faintest Cepheids in IC 1613 which had not been finished by Baade. Magnitudes have been reduced to Freedman's new photometric scale. The P-L relation is extended to periods of 2 days using these new data. Comparison of the total Cepheid data now available in IC 1613 with the data in LMC shows no significant slope difference in the two P-L relations for periods of less than 10 days despite the lower metallicity of the young stars in IC 1613. Fifty new faint Cepheid candidates have been found in IC 1613 by blinking plates not used for this purpose by Baade. Most of these stars will have probable periods of less than 2 days, which will eventually permit an extension of the P-L relation in IC 1613 to fainter magnitudes when the photometry and period determinations are completed. 18 refs

  19. TYPE Ia SUPERNOVA LIGHT CURVE INFERENCE: HIERARCHICAL MODELS IN THE OPTICAL AND NEAR-INFRARED

    Mandel, Kaisey S.; Narayan, Gautham; Kirshner, Robert P.

    2011-01-01

    We have constructed a comprehensive statistical model for Type Ia supernova (SN Ia) light curves spanning optical through near-infrared (NIR) data. A hierarchical framework coherently models multiple random and uncertain effects, including intrinsic supernova (SN) light curve covariances, dust extinction and reddening, and distances. An improved BAYESN Markov Chain Monte Carlo code computes probabilistic inferences for the hierarchical model by sampling the global probability density of parameters describing individual SNe and the population. We have applied this hierarchical model to optical and NIR data of 127 SNe Ia from PAIRITEL, CfA3, Carnegie Supernova Project, and the literature. We find an apparent population correlation between the host galaxy extinction A V and the ratio of total-to-selective dust absorption R V . For SNe with low dust extinction, A V ∼ V ∼ 2.5-2.9, while at high extinctions, A V ∼> 1, low values of R V < 2 are favored. The NIR luminosities are excellent standard candles and are less sensitive to dust extinction. They exhibit low correlation with optical peak luminosities, and thus provide independent information on distances. The combination of NIR and optical data constrains the dust extinction and improves the predictive precision of individual SN Ia distances by about 60%. Using cross-validation, we estimate an rms distance modulus prediction error of 0.11 mag for SNe with optical and NIR data versus 0.15 mag for SNe with optical data alone. Continued study of SNe Ia in the NIR is important for improving their utility as precise and accurate cosmological distance indicators.

  20. Imprints of the quasar structure in time-delay light curves: Microlensing-aided reverberation mapping

    Sluse, D.; Tewes, M.

    2014-11-01

    The advent of large area photometric surveys has raised a great deal of interest in the possibility of using broadband photometric data, instead of spectra, to measure the size of the broad line region of active galactic nuclei. We describe here a new method that uses time-delay lensed quasars where one or several images are affected by microlensing due to stars in the lensing galaxy. Because microlensing decreases (or increases) the flux of the continuum compared to the broad line region, it changes the contrast between these two emission components. We show that this effect can be used to effectively disentangle the intrinsic variability of those two regions, offering the opportunity to perform reverberation mapping based on single-band photometric data. Based on simulated light curves generated using a damped random walk model of quasar variability, we show that measurement of the size of the broad line region can be achieved using this method, provided one spectrum has been obtained independently during the monitoring. This method is complementary to photometric reverberation mapping and could also be extended to multi-band data. Because the effect described above produces a variability pattern in difference light curves between pairs of lensed images that is correlated with the time-lagged continuum variability, it can potentially produce systematic errors in measurement of time delays between pairs of lensed images. Simple simulations indicate that time-delay measurement techniques that use a sufficiently flexible model for the extrinsic variability are not affected by this effect and produce accurate time delays.

  1. Transit Timing Variation analysis with Kepler light curves of KOI 227 and Kepler 93b

    Dulz, Shannon; Reed, Mike

    2017-01-01

    By searching for transit signals in approximately 150,000 stars, NASA’s Kepler Space telescope found thousands of exoplanets over its primary mission from 2009 to 2013 (Tenenbaum et al. 2014, ApJS, 211, 6). Yet, a detailed follow-up examination of Kepler light curves may contribute more evidence on system dynamics and planetary atmospheres of these objects. Kepler’s continuous observing of these systems over the mission duration produced light curves of sufficient duration to allow for the search for transit timing variations. Transit timing variations over the course of many orbits may indicate a precessing orbit or the existence of a non-transiting third body such as another exoplanet. Flux contributions of the planet just prior to secondary eclipse may provide a measurement of bond albedo from the day-side of the transiting planet. Any asymmetries of the transit shape may indicate thermal asymmetries which can measure upper atmosphere motion of the planet. These two factors can constrain atmospheric models of close orbiting exoplanets. We first establish our procedure with the well-documented TTV system, KOI 227 (Nesvorny et al. 2014, ApJ, 790, 31). Using the test case of KOI 227, we analyze Kepler-93b for TTVs and day-side flux contributions. Kepler-93b is likely a rocky planet with R = 1.50 ± 0.03 Earth Radii and M = 2.59 ± 2.0 Earth Masses (Marcy et al. 2014, ApJS, 210, 20). This research is funded by a NASA EPSCoR grant.

  2. REVISITING EVIDENCE OF CHAOS IN X-RAY LIGHT CURVES: THE CASE OF GRS 1915+105

    Mannattil, Manu; Gupta, Himanshu; Chakraborty, Sagar, E-mail: mmanu@iitk.ac.in, E-mail: hiugupta@iitk.ac.in, E-mail: sagarc@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Uttar Pradesh 208016 (India)

    2016-12-20

    Nonlinear time series analysis has been widely used to search for signatures of low-dimensional chaos in light curves emanating from astrophysical bodies. A particularly popular example is the microquasar GRS 1915+105, whose irregular but systematic X-ray variability has been well studied using data acquired by the Rossi X-ray Timing Explorer . With a view to building simpler models of X-ray variability, attempts have been made to classify the light curves of GRS 1915+105 as chaotic or stochastic. Contrary to some of the earlier suggestions, after careful analysis, we find no evidence for chaos or determinism in any of the GRS 1915+105 classes. The dearth of long and stationary data sets representing all the different variability classes of GRS 1915+105 makes it a poor candidate for analysis using nonlinear time series techniques. We conclude that either very exhaustive data analysis with sufficiently long and stationary light curves should be performed, keeping all the pitfalls of nonlinear time series analysis in mind, or alternative schemes of classifying the light curves should be adopted. The generic limitations of the techniques that we point out in the context of GRS 1915+105 affect all similar investigations of light curves from other astrophysical sources.

  3. Photometric light curves for seven rapidly-rotating K dwarfs in the Pleiades and Alpha Persei clusters

    Stauffer, John R.; Schild, Rudolph A.; Baliunas, Sallie L.; Africano, John L.

    1987-01-01

    Light curves and period estimates were obtained for several Pleiades and Alpha Persei cluster K dwarfs which were identified as rapid rotators in earlier spectroscopic studies. A few of the stars have previously-published light curves, making it possible to study the long-term variability of the light-curve shapes. The general cause of the photometric variability observed for these stars is an asymmetric distribution of photospheric inhomogeneities (starspots). The presence of these inhomogeneities combined with the rotation of the star lead to the light curves observed. The photometric periods derived are thus identified with the rotation period of the star, making it possible to estimate equatorial rotational velocities for these K dwarfs. These data are of particular importance because the clusters are sufficiently young that stars of this mass should have just arrived on the main sequence. These data could be used to estimate the temperatures and sizes of the spot groups necessary to produce the observed light curves for these stars.

  4. Type Ia Supernova Light Curve Inference: Hierarchical Models for Nearby SN Ia in the Optical and Near Infrared

    Mandel, Kaisey; Kirshner, R. P.; Narayan, G.; Wood-Vasey, W. M.; Friedman, A. S.; Hicken, M.

    2010-01-01

    I have constructed a comprehensive statistical model for Type Ia supernova light curves spanning optical through near infrared data simultaneously. The near infrared light curves are found to be excellent standard candles (sigma(MH) = 0.11 +/- 0.03 mag) that are less vulnerable to systematic error from dust extinction, a major confounding factor for cosmological studies. A hierarchical statistical framework incorporates coherently multiple sources of randomness and uncertainty, including photometric error, intrinsic supernova light curve variations and correlations, dust extinction and reddening, peculiar velocity dispersion and distances, for probabilistic inference with Type Ia SN light curves. Inferences are drawn from the full probability density over individual supernovae and the SN Ia and dust populations, conditioned on a dataset of SN Ia light curves and redshifts. To compute probabilistic inferences with hierarchical models, I have developed BayeSN, a Markov Chain Monte Carlo algorithm based on Gibbs sampling. This code explores and samples the global probability density of parameters describing individual supernovae and the population. I have applied this hierarchical model to optical and near infrared data of over 100 nearby Type Ia SN from PAIRITEL, the CfA3 sample, and the literature. Using this statistical model, I find that SN with optical and NIR data have a smaller residual scatter in the Hubble diagram than SN with only optical data. The continued study of Type Ia SN in the near infrared will be important for improving their utility as precise and accurate cosmological distance indicators.

  5. Periodicity Analysis of X-ray Light Curves of SS 433

    Wang, Jun-yi; Lu, Xiang-long; Zhao, Qiu-wen; Dong, Dian-qiao; Lao, Bao-qiang; Lu, Yang; Wei, Yan-heng; Wu, Xiao-cong; An, Tao

    2017-01-01

    SS 433 is sofar the unique X-ray binary that has the simultaneously detected orbital period, super-orbital period, and nutation period, as well as a bidirectional spiral jet. The study on its X-ray light variability is helpful for understanding the dynamic process of the system, and the correlations between the different wavebands. In this paper, two time-series analysis techniques, i.e., the Lomb-Scargle periodogram and weighted wavelet Z-transform, are employed to search for the periods in the Swift/BAT (Burst Alert Telescope) (15-50 keV) and RXTE/ASM (Rose X-ray Timing Explorer/All Sky Monitor) (1.5-3, 3- 4, and 5-12 keV) light curves of SS 433, and the Monte Carlo simulation is performed for the obtained periodical components. For the 15-50 keV energy band, five significant periodical components are detected, which are P1(∼6.29 d), P2 (∼6.54 d), P3 (∼13.08 d), P4 (∼81.50 d), and P5 (∼162.30 d). For the 3-5 and 5-12 keV energy bands, the periodical components P3 (∼13 d) and P5 (∼162 d) are detected in both energy bands. However, for the 1.5-3 keV energy band, no significant periodic signal is detected. P5 is the strongest periodic signal in the power spectrum for all the energy bands of 3-5, 5-12, and 15-50 keV, and it is consistent with the previous result obtained from the study of optical light curves. Furthermore, in combination with the radio spiral jet of SS 433, it is suggested that the X-ray and optical variability of P5 (∼162 d) is probably related to the precession of its relativistic jet. The high correlation between the X-ray and optical light curves may also imply that the X-ray and optical radiations are of the same physical origin. P3 shows a good agreement with the orbital period (∼13.07 d) obtained by the previous study, and P2 and P4 are respectively the high-frequency harmonics of P3 and P5. P1 is detected only in the power spectrum of the 15-50 keV energy band, and it is consistent with the nutation period of the system. As

  6. Implications of the Early X-Ray Afterglow Light Curves of Swift GRBs

    Granot, Jonathan; /KIPAC, Menlo Park; Konigl, Arieh; /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI; Piran, Tsvi; /Hebrew U.

    2006-01-17

    According to current models, gamma-ray bursts (GRBs) are produced when the energy carried by a relativistic outflow is dissipated and converted into radiation. The efficiency of this process, {epsilon}{sub {gamma}}, is one of the critical factors in any GRB model. The X-ray afterglow light curves of Swift GRBs show an early stage of flattish decay. This has been interpreted as reflecting energy injection. When combined with previous estimates, which have concluded that the kinetic energy of the late ({approx}> 10 hr) afterglow is comparable to the energy emitted in {gamma}-rays, this interpretation implies very high values of {epsilon}{sub {gamma}}, corresponding to {approx}> 90% of the initial energy being converted into {gamma}-rays. Such a high efficiency is hard to reconcile with most models, including in particular the popular internal-shocks model. We re-analyze the derivation of the kinetic energy from the afterglow X-ray flux and re-examine the resulting estimates of the efficiency. We confirm that, if the flattish decay arises from energy injection and the pre-Swift broad-band estimates of the kinetic energy are correct, then {epsilon}{sub {gamma}} {approx}> 0.9. We discuss various issues related to this result, including an alternative interpretation of the light curve in terms of a two-component outflow model, which we apply to the X-ray observations of GRB 050315. We point out, however, that another interpretation of the flattish decay--a variable X-ray afterglow efficiency (e.g., due to a time dependence of afterglow shock microphysical parameters)--is possible. We also show that direct estimates of the kinetic energy from the late X-ray afterglow flux are sensitive to the assumed values of the shock microphysical parameters and suggest that broad-band afterglow fits might have underestimated the kinetic energy (e.g., by overestimating the fraction of electrons that are accelerated to relativistic energies). Either one of these possibilities implies a

  7. THE INFRARED LIGHT CURVE OF SN 2011fe IN M101 AND THE DISTANCE TO M101

    Matheson, T.; Joyce, R. R.; Allen, L. E.; Saha, A.; Silva, D. R.; Binkert, W. S.; Butler, K.; Everett, M.; Wood-Vasey, W. M.; Adams, J. J.; Anderson, R. E.; Beck, T. L.; Bentz, M. C.; Bershady, M. A.; Eigenbrot, A.; Gallagher, J. S.; Camarata, M. A.; Garnavich, P. M.; Glikman, E.; Harbeck, D.

    2012-01-01

    We present near-infrared light curves of supernova (SN) 2011fe in M101, including 34 epochs in H band starting 14 days before maximum brightness in the B band. The light curve data were obtained with the WIYN High-Resolution Infrared Camera. When the data are calibrated using templates of other Type Ia SNe, we derive an apparent H-band magnitude at the epoch of B-band maximum of 10.85 ± 0.04. This implies a distance modulus for M101 that ranges from 28.86 to 29.17 mag, depending on which absolute calibration for Type Ia SNe is used.

  8. The Infrared Light Curve of SN 2011fe in M101 and the Distance to M101

    Matheson, T.; Joyce, R. R.; Allen, L. E.; Saha, A.; Silva, D. R.; Wood-Vasey, W. M.; Adams, J. J.; Anderson, R. E.; Beck, T. L.; Bentz, M. C.; Bershady, M. A.; Binkert, W. S.; Butler, K.; Camarata, M. A.; Eigenbrot, A.

    2012-01-01

    We present near infra-red light curves of supernova (SN) 2011fe in M101, including 34 epochs in H band starting fourteen days before maximum brightness in the B-band. The light curve data were obtained with the WIYN High-Resolution Infrared Camera (WHIRC). When the data are calibrated using templates of other Type Ia SNe, we derive an apparent H-band magnitude at the epoch of B-band maximum of 10.85 \\pm 0.04. This implies a distance modulus for M101 that ranges from 28.86 to 29.17 mag, depend...

  9. THE INFRARED LIGHT CURVE OF SN 2011fe IN M101 AND THE DISTANCE TO M101

    Matheson, T.; Joyce, R. R.; Allen, L. E.; Saha, A.; Silva, D. R.; Binkert, W. S.; Butler, K.; Everett, M. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Wood-Vasey, W. M. [Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT-PACC), University of Pittsburgh, 3941 O' Hara Street, Pittsburgh, PA 15260 (United States); Adams, J. J. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Anderson, R. E.; Beck, T. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Bershady, M. A.; Eigenbrot, A.; Gallagher, J. S. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706 (United States); Camarata, M. A. [Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515 (United States); Garnavich, P. M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Glikman, E. [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Harbeck, D., E-mail: matheson@noao.edu [WIYN Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); and others

    2012-07-20

    We present near-infrared light curves of supernova (SN) 2011fe in M101, including 34 epochs in H band starting 14 days before maximum brightness in the B band. The light curve data were obtained with the WIYN High-Resolution Infrared Camera. When the data are calibrated using templates of other Type Ia SNe, we derive an apparent H-band magnitude at the epoch of B-band maximum of 10.85 {+-} 0.04. This implies a distance modulus for M101 that ranges from 28.86 to 29.17 mag, depending on which absolute calibration for Type Ia SNe is used.

  10. High-precision performance testing of the LHC power converters

    Bastos, M; Dreesen, P; Fernqvist, G; Fournier, O; Hudson, G

    2007-01-01

    The magnet power converters for LHC were procured in three parts, power part, current transducers and control electronics, to enable a maximum of industrial participation in the manufacturing and still guarantee the very high precision (a few parts in 10-6) required by LHC. One consequence of this approach was several stages of system tests: factory reception tests, CERN reception tests, integration tests , short-circuit tests and commissioning on the final load in the LHC tunnel. The majority of the power converters for LHC have now been delivered, integrated into complete converter and high-precision performance testing is well advanced. This paper presents the techniques used for high-precision testing and the results obtained.

  11. On Some Statistical Properties of GRBs with Measured Redshifts Having Peaks in Optical Light Curves

    Grigorii Beskin

    2013-01-01

    Full Text Available We studied the subset of optical light curves of gamma-ray bursts with measured redshifts and well-sampled R band data that have clearly detected peaks. Among 43 such events, 11 are promptoptical peaks (P, coincident with gamma-ray activity, 22 are purely afterglows (A, and 10 more carrythe signatures of an underlying activity (A(U. We studied pair correlations of their gamma-ray andoptical parameters, e.g. total energetics, peak optical luminosities, and durations. The main outcomeof our study is the detection of source frame correlations between both optical peak luminosity and total energy and the redshift for classes A and A(U, and the absence of such a correlation for class Pevents. This result seems to provide evidence of the cosmological evolution of a medium around the burst defining class A and A(U energetics, and the absence of cosmological evolution of the internal properties of GRB engines. We also discuss some other prominent correlations.

  12. THE XMM-NEWTON/EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6

    Ignace, R.; Gayley, K. G.; Hamann, W.-R.; Oskinova, L. M.; Huenemoerder, D. P.; Pollock, A. M. T.; McFall, M.

    2013-01-01

    We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds

  13. THE XMM-NEWTON/EPIC X-RAY LIGHT CURVE ANALYSIS OF WR 6

    Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37663 (United States); Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52245 (United States); Hamann, W.-R.; Oskinova, L. M. [Institute for Physics and Astronomy, University Potsdam, D-14476 Potsdam (Germany); Huenemoerder, D. P. [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States); Pollock, A. M. T. [European Space Agency XMM-Newton Science Operations Centre, European Space Astronomy Centre, Apartado 78, Villanueva de la Cañada, E-28691 Madrid (Spain); McFall, M., E-mail: ignace@etsu.edu [Department of Physics, 191 W. Woodruff Avenue, Ohio State University, Columbus, OH 43210 (United States)

    2013-09-20

    We obtained four pointings of over 100 ks each of the well-studied Wolf-Rayet star WR 6 with the XMM-Newton satellite. With a first paper emphasizing the results of spectral analysis, this follow-up highlights the X-ray variability clearly detected in all four pointings. However, phased light curves fail to confirm obvious cyclic behavior on the well-established 3.766 day period widely found at longer wavelengths. The data are of such quality that we were able to conduct a search for event clustering in the arrival times of X-ray photons. However, we fail to detect any such clustering. One possibility is that X-rays are generated in a stationary shock structure. In this context we favor a corotating interaction region (CIR) and present a phenomenological model for X-rays from a CIR structure. We show that a CIR has the potential to account simultaneously for the X-ray variability and constraints provided by the spectral analysis. Ultimately, the viability of the CIR model will require both intermittent long-term X-ray monitoring of WR 6 and better physical models of CIR X-ray production at large radii in stellar winds.

  14. A New Relationship Between Soft X-Rays and EUV Flare Light Curves

    Thiemann, Edward

    2016-05-01

    Solar flares are the result of magnetic reconnection in the solar corona which converts magnetic energy into kinetic energy resulting in the rapid heating of solar plasma. As this plasma cools, it emits radiation at different EUV wavelengths when the dropping temperature passes a line’s temperature of formation. This results in a delay in the emissions from cooler EUV lines relative to hotter EUV lines. Therefore, characterizing how this hot plasma cools is important for understanding how the corresponding geo-effective extreme ultraviolet (EUV) irradiance evolves in time. I present a simple new framework in which to study flare cooling by using a Lumped Element Thermal Model (LETM). LETM is frequently used in science and engineering to simplify a complex multi-dimensional thermal system by reducing it to a 0-D thermal circuit. For example, a structure that conducts heat out of a system is simplified with a resistive element and a structure that allows a system to store heat is simplified with a capacitive element. A major advantage of LETM is that the specific geometry of a system can be ignored, allowing for an intuitive analysis of the major thermal processes. I show that LETM is able to accurately reproduce the temporal evolution of cooler flare emission lines based on hotter emission line evolution. In particular, it can be used to predict the evolution of EUV flare light curves using the NOAA X-Ray Sensor (XRS).

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

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

    1983-01-01

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

  16. IRTF/SPEX OBSERVATIONS OF THE UNUSUAL KEPLER LIGHT CURVE SYSTEM KIC 8462852

    Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Sitko, M. L. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 (United States); Marengo, M., E-mail: carey.lisse@jhuapl.edu [Department of Physics and Astronomy, Iowa State University, 12 Physics Hall, Ames, IA 50010 (United States)

    2015-12-20

    We have utilized the NASA/IRTF 3 m SpeX instrument’s high-resolution spectral mode to observe and characterize the near-infrared flux emanating from the unusual Kepler light curve system KIC 8462852. By comparing the resulting 0.8–4.2 μm spectrum to a mesh of model photospheric spectra, the 6 emission line analyses of the Rayner et al. catalog, and the 25 system collections of debris disks we have observed to date using SpeX under the Near InfraRed Debris disk Survey, we have been able to additionally characterize the system. Within the errors of our measurements, this star looks like a normal solar abundance main-sequence F1V to F3V dwarf star without any obvious traces of significant circumstellar dust or gas. Using Connelley and Greene’s emission measures, we also see no evidence of significant ongoing accretion onto the star nor any stellar outflow away from it. Our results are inconsistent with large amounts of static close-in obscuring material or the unusual behavior of a YSO system, but are consistent with the favored episodic giant comet models of a Gyr old stellar system favored by Boyajian et al. We speculate that KIC 8462852, like the ∼1.4 Gyr old F2V system η Corvi, is undergoing a late heavy bombardment, but is only in its very early stages.

  17. M DWARFS IN SLOAN DIGITAL SKY SURVEY STRIPE 82: PHOTOMETRIC LIGHT CURVES AND FLARE RATE ANALYSIS

    Kowalski, Adam F.; Hawley, Suzanne L.; Hilton, Eric J.; Becker, Andrew C.; Sesar, Branimir; West, Andrew A.; Bochanski, John J.

    2009-01-01

    We present a flare rate analysis of 50,130 M dwarf light curves in Sloan Digital Sky Survey Stripe 82. We identified 271 flares using a customized variability index to search ∼2.5 million photometric observations for flux increases in the u and g bands. Every image of a flaring observation was examined by eye and with a point-spread function-matching and image subtraction tool to guard against false positives. Flaring is found to be strongly correlated with the appearance of Hα in emission in the quiet spectrum. Of the 99 flare stars that have spectra, we classify eight as relatively inactive. The flaring fraction is found to increase strongly in stars with redder colors during quiescence, which can be attributed to the increasing flare visibility and increasing active fraction for redder stars. The flaring fraction is strongly correlated with |Z| distance such that most stars that flare are within 300 pc of the Galactic plane. We derive flare u-band luminosities and find that the most luminous flares occur on the earlier-type m dwarfs. Our best estimate of the lower limit on the flaring rate (averaged over Stripe 82) for flares with Δu ≥ 0.7 mag on stars with u -1 deg -2 but can vary significantly with the line of sight.

  18. Characterizing high-energy light curves of Fermi/Lat GRBs

    Gillette, Jarred [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-21

    A systematic analysis of the light curves of Gamma-Ray Burst (GRBs) with redshift and detected at high-energy (> 100 MeV) by Fermi/LAT has never been done before our work, because there were only a handful of detections. Now we have 20 of those, which we can use to characterize the GRBs in their rest frame. We compared a characteristic decay times Tc of GRBs with redshifts using the new “Pass 8” data, and used a Crystal Ball function to parametrize GRB characteristics. An unexpected anti-correlation between Tc and the peak flux was observed. This means that brighter peaked GRBs have shorter durations. There is also no correlation between the Tc and the decay index, which makes the anti-correlation with brightness more clear. This results appears to be consistent with the External Shock model, which is one of the competing hypothesis on the origin of the high-energy emission. We did not observe any bimodality, which is seen in GRBs at lower energies.

  19. Gamma-ray Burst X-ray Flares Light Curve Fitting

    Aubain, Jonisha

    2018-01-01

    Gamma Ray Bursts (GRBs) are the most luminous explosions in the Universe. These electromagnetic explosions produce jets demonstrated by a short burst of prompt gamma-ray emission followed by a broadband afterglow. There are sharp increases of flux in the X-ray light curves known as flares that occurs in about 50% of the afterglows. In this study, we characterized all of the X-ray afterglows that were detected by the Swift X-ray Telescope (XRT), whether with flares or without. We fit flares to the Norris function (Norris et al. 2005) and power laws with breaks where necessary (Racusin et al. 2009). After fitting the Norris function and power laws, we search for the residual pattern detected in prompt GRB pulses (Hakkila et al. 2014, 2015, 2017), that may indicate a common signature of shock physics. If we find the same signature in flares and prompt pulses, it provides insight into what causes them, as well as, how these flares are produced.

  20. Pair-instability Supernova Simulations: Progenitor Evolution, Explosion, and Light Curves

    Gilmer, Matthew S.; Fröhlich, Carla [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Kozyreva, Alexandra [The Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Hirschi, Raphael [Astrophysics group, School of Chemical and Physical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Yusof, Norhasliza, E-mail: msgilmer@ncsu.edu [Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2017-09-10

    In recent years, the viability of the pair-instability supernova (PISN) scenario for explaining superluminous supernovae has all but disappeared except for a few slowly-evolving examples. However, PISNe are not predicted to be superluminous throughout the bulk of their mass range. In fact, it is more likely that the first PISN we see (if we have not seen one already) will not be superluminous. Here, we present hydrodynamic simulations of PISNe for four stellar models with unique envelope properties spanning the PISN mass range. In addition, we compute synthetic light curves (LCs) for comparison with current and future observations. We also investigate, in the context of our most massive model, the prospect of mixing in the supernova ejecta, alleviating discrepancies between current PISN models and the remaining superluminous candidate events. To this end, we present the first published 3D hydrodynamic simulations of PISNe. After achieving convergence between 1D, 2D, and 3D simulations, we examine mixing in the supernova ejecta and its affect on the bolometric LC. We observe slight deviations from spherical symmetry, which increase with the number of dimensions. We find no significant effects on the bolometric LC; however, we conclude that mixing between the silicon and oxygen rich layers caused by the Rayleigh–Taylor instability may affect spectra.

  1. THE IMPORTANCE OF {sup 56}Ni IN SHAPING THE LIGHT CURVES OF TYPE II SUPERNOVAE

    Nakar, Ehud; Poznanski, Dovi [The Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Katz, Boaz [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100 (Israel)

    2016-06-01

    What intrinsic properties shape the light curves of SNe II? To address this question we derive observational measures that are robust (i.e., insensitive to detailed radiative transfer) and constrain the contribution from {sup 56}Ni as well as a combination of the envelope mass, progenitor radius, and explosion energy. By applying our methods to a sample of SNe II from the literature, we find that a {sup 56}Ni contribution is often significant. In our sample, its contribution to the time-weighted integrated luminosity during the photospheric phase ranges between 8% and 72% with a typical value of 30%. We find that the {sup 56}Ni relative contribution is anti-correlated with the luminosity decline rate. When added to other clues, this in turn suggests that the flat plateaus often observed in SNe II are not a generic feature of the cooling envelope emission, and that without {sup 56}Ni many of the SNe that are classified as II-P would have shown a decline rate that is steeper by up to 1 mag/100 days. Nevertheless, we find that the cooling envelope emission, and not {sup 56}Ni contribution, is the main driver behind the observed range of decline rates. Furthermore, contrary to previous suggestions, our findings indicate that fast decline rates are not driven by lower envelope masses. We therefore suggest that the difference in observed decline rates is mainly a result of different density profiles of the progenitors.

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

    Kato, Mariko; Hachisu, Izumi; Mikołajewska, Joanna

    2013-01-01

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

  3. Modelling gamma-ray light curves of phase-aligned millisecond pulsars

    Chang, Shan; Zhang, Li; Li, Xiang; Jiang, Zejun

    2018-04-01

    Three gamma-ray millisecond pulsars (MSPs), PSR J1939+2134, PSR J1959+2048, and PSR J0034-0534, have been confirmed to have a common feature of phase-aligned in radio and gamma-ray bands. With a geometric (two-pole caustic) model and a physical outer gap model (revised 3D outer gap model) in a three dimensional (3D) retarded magnetic dipole with a perturbation magnetic field, the observed features of these MSPs are studied. In order to obtained the best-fitting model parameters, the Markov chain Monte Carlo technique is used and reasonable GeV band light curves for three MSPs are given. Our calculations indicate that MSPs emit high energy photons with smaller inclination angles (α ≈ 10°-50°), larger view angles (ζ ≈ 65°-100°), and smaller perturbation factor (ɛ ≈ -0.15-0.1). Note that the factor ɛ, describing the strength of the perturbed magnetic field, is all less than zero in these two models, so the magnetic field caused by current-induced play a leading role in the pulsed location of MSPs.

  4. A COMPREHENSIVE ANALYSIS OF SWIFT/X-RAY TELESCOPE DATA. IV. SINGLE POWER-LAW DECAYING LIGHT CURVES VERSUS CANONICAL LIGHT CURVES AND IMPLICATIONS FOR A UNIFIED ORIGIN OF X-RAYS

    Liang Enwei; Lue Houjun; Hou Shujin; Zhang Binbin; Zhang Bing

    2009-01-01

    By systematically analyzing the Swift/XRT light curves detected before 2009 July, we find 19 light curves that monotonously decay as a single power law (SPL) with an index of 1 ∼ 1.7 from tens (or hundreds) of seconds to ∼10 5 s post the gamma-ray burst (GRB) trigger. They are apparently different from the canonical light curves characterized by a shallow-to-normal decay transition. We compare the observations of the prompt gamma rays and the X-rays for these two samples of GRBs (SPL vs. canonical). No statistical difference is found in the prompt gamma-ray properties for the two samples. The X-ray properties of the two samples are also similar, although the SPL sample tends to have a slightly lower neutral hydrogen absorption column for the host galaxies and a slightly larger energy release compared with the canonical sample. The SPL X-ray Telescope (XRT) light curves in the burst frame gradually merge into a conflux, and their luminosities at 10 5 s are normally distributed at log L/ergs s -1 = 45.6 ± 0.5. The normal decay segment of the canonical XRT light curves has the same feature. Similar to the normal decay segment, the SPL light curves satisfy the closure relations and therefore can be roughly explained with external shock models. In the scenario that the X-rays are the afterglows of the GRB fireball, our results indicate that the shallow decay would be due to energy injection into the fireball and the total energy budget after injection for both samples of GRBs is comparable. More intriguing, we find that a prior X-ray emission model proposed by Yamazaki is more straightforward to interpret the observed XRT data. We show that the zero times (T 0 ) of the X-rays are 10 2 -10 5 s prior to the GRB trigger for the canonical sample, and satisfy a log-normal distribution. The negligible T 0 's of the SPL sample are consistent with being the tail of T 0 distributions at low end, suggesting that the SPL sample and the canonical sample may be from a same

  5. High precision mass measurements in Ψ and Υ families revisited

    Artamonov, A.S.; Baru, S.E.; Blinov, A.E.

    2000-01-01

    High precision mass measurements in Ψ and Υ families performed in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the J/Ψ(1S) and Ψ(2S) mass measurements [ru

  6. Properties of the proton therapy. A high precision radiotherapy

    Anon.

    2005-01-01

    The proton therapy is a radiotherapy using protons beams. The protons present interesting characteristics but they need heavy technologies to be used, such particles accelerators, radiation protection wall and sophisticated technologies to reach the high precision allowed by their ballistic qualities (planning of treatment, beam conformation and patient positioning). (N.C.)

  7. The study of high precision neutron moisture gauge

    Liu Shengkang; Bao Guanxiong; Sang Hai; Zhu Yuzhen

    1993-01-01

    The principle, structure and calibration experiment of the high precision neutron moisture gauge (insertion type) are described. The gauge has been appraised. The precision of the measuring moisture of coke is lower than 0.5%, and the range of the measuring moisture is 2%-12%. The economic benefit of the gauge application is good

  8. Layered compression for high-precision depth data.

    Miao, Dan; Fu, Jingjing; Lu, Yan; Li, Shipeng; Chen, Chang Wen

    2015-12-01

    With the development of depth data acquisition technologies, access to high-precision depth with more than 8-b depths has become much easier and determining how to efficiently represent and compress high-precision depth is essential for practical depth storage and transmission systems. In this paper, we propose a layered high-precision depth compression framework based on an 8-b image/video encoder to achieve efficient compression with low complexity. Within this framework, considering the characteristics of the high-precision depth, a depth map is partitioned into two layers: 1) the most significant bits (MSBs) layer and 2) the least significant bits (LSBs) layer. The MSBs layer provides rough depth value distribution, while the LSBs layer records the details of the depth value variation. For the MSBs layer, an error-controllable pixel domain encoding scheme is proposed to exploit the data correlation of the general depth information with sharp edges and to guarantee the data format of LSBs layer is 8 b after taking the quantization error from MSBs layer. For the LSBs layer, standard 8-b image/video codec is leveraged to perform the compression. The experimental results demonstrate that the proposed coding scheme can achieve real-time depth compression with satisfactory reconstruction quality. Moreover, the compressed depth data generated from this scheme can achieve better performance in view synthesis and gesture recognition applications compared with the conventional coding schemes because of the error control algorithm.

  9. AGAINST THE WIND: RADIO LIGHT CURVES OF TYPE IA SUPERNOVAE INTERACTING WITH LOW-DENSITY CIRCUMSTELLAR SHELLS

    Harris, Chelsea E.; Nugent, Peter E.; Kasen, Daniel N., E-mail: chelseaharris@berkeley.edu [Astronomy Department, University of California Berkeley, Berkeley, CA (United States)

    2016-06-01

    For decades a wide variety of observations spanning the radio through optical and on to the X-ray have attempted to uncover signs of type Ia supernovae (SNe Ia) interacting with a circumstellar medium (CSM). The goal of these studies is to constrain the nature of the hypothesized SN Ia mass-donor companion. A continuous CSM is typically assumed when interpreting observations of interaction. However, while such models have been successfully applied to core-collapse SNe, the assumption of continuity may not be accurate for SNe Ia, because shells of CSM could be formed by pre-supernova eruptions (novae). In this work, we model the interaction of SNe with a spherical, low-density, finite-extent CSM and create a suite of synthetic radio synchrotron light curves. We find that CSM shells produce sharply peaked light curves. We also identify a fiducial set of models that obey a common evolution and can be used to generate radio light curves for an interaction with an arbitrary shell. The relations obeyed by the fiducial models can be used to deduce CSM properties from radio observations; we demonstrate this by applying them to the nondetections of SN 2011fe and SN 2014J. Finally, we explore a multiple shell CSM configuration and describe its more complicated dynamics and the resultant radio light curves.

  10. On the mean profiles of radio pulsars - II. Reconstruction of complex pulsar light curves and other new propagation effects

    Hakobyan, H. L.; Beskin, V. S.; Philippov, A. A.

    2017-08-01

    Our previous paper outlined the general aspects of the theory of radio light curve and polarization formation for pulsars. We predicted the one-to-one correspondence between the tilt of the linear polarization position angle of the the circular polarization. However, some of the radio pulsars indicate a clear deviation from that correlation. In this paper, we apply the theory of the radio wave propagation in the pulsar magnetosphere for the analysis of individual effects leading to these deviations. We show that within our theory the circular polarization of a given mode can switch its sign, without the need to introduce a new radiation mode or other effects. Moreover, we show that the generation of different emission modes on different altitudes can explain pulsars, that presumably have the X-O-X light-curve pattern, different from what we predict. General properties of radio emission within our propagation theory are also discussed. In particular, we calculate the intensity patterns for different radiation altitudes and present light curves for different observer viewing angles. In this context we also study the light curves and polarization profiles for pulsars with interpulses. Further, we explain the characteristic width of the position angle curves by introducing the concept of a wide emitting region. Another important feature of radio polarization profiles is the shift of the position angle from the centre, which in some cases demonstrates a weak dependence on the observation frequency. Here we demonstrate that propagation effects do not necessarily imply a significant frequency-dependent change of the position angle curve.

  11. Investigating light curve modulation via kernel smoothing. I. Application to 53 fundamental mode and first-overtone Cepheids in the LMC

    Süveges, Maria; Anderson, Richard I.

    2018-03-01

    Context. Recent studies have revealed a hitherto unknown complexity of Cepheid pulsations by discovering irregular modulated variability using photometry, radial velocities, and interferometry. Aim. We aim to perform a statistically rigorous search and characterization of such phenomena in continuous time, applying it to 53 classical Cepheids from the OGLE-III catalog. Methods: We have used local kernel regression to search for both period and amplitude modulations simultaneously in continuous time and to investigate their detectability. We determined confidence intervals using parametric and non-parametric bootstrap sampling to estimate significance, and investigated multi-periodicity using a modified pre-whitening approach that relies on time-dependent light curve parameters. Results: We find a wide variety of period and amplitude modulations and confirm that first overtone pulsators are less stable than fundamental mode Cepheids. Significant temporal variations in period are more frequently detected than those in amplitude. We find a range of modulation intensities, suggesting that both amplitude and period modulations are ubiquitous among Cepheids. Over the 12-year baseline offered by OGLE-III, we find that period changes are often nonlinear, sometimes cyclic, suggesting physical origins beyond secular evolution. Our method detects modulations (period and amplitude) more efficiently than conventional methods that are reliant on certain features in the Fourier spectrum, and pre-whitens time series more accurately than using constant light curve parameters, removing spurious secondary peaks effectively. Conclusions: Period and amplitude modulations appear to be ubiquitous among Cepheids. Current detectability is limited by observational cadence and photometric precision: detection of amplitude modulation below 3 mmag requires space-based facilities. Recent and ongoing space missions (K2, BRITE, MOST, CoRoT) as well as upcoming ones (TESS, PLATO) will

  12. Modeling Phase-Aligned Gamma-Ray and Radio Millisecond Pulsar Light Curves

    Venter, C.; Johnson, T.; Harding, A.

    2012-01-01

    Since the discovery of the first eight gamma-ray millisecond pulsars (MSPs) by the Fermi Large Area Telescope, this population has been steadily expanding. Four of the more recent detections, PSR J00340534, PSR J1939+2134 (B1937+21; the first MSP ever discovered), PSR J1959+2048 (B1957+20; the first discovery of a black widow system), and PSR J2214+3000, exhibit a phenomenon not present in the original discoveries: nearly phase-aligned radio and gamma-ray light curves (LCs). To account for the phase alignment, we explore models where both the radio and gamma-ray emission originate either in the outer magnetosphere near the light cylinder or near the polar caps. Using a Markov Chain Monte Carlo technique to search for best-fit model parameters, we obtain reasonable LC fits for the first three of these MSPs in the context of altitude-limited outer gap (alOG) and two-pole caustic (alTPC) geometries (for both gamma-ray and radio emission). These models differ from the standard outer gap (OG)/two-pole caustic (TPC) models in two respects: the radio emission originates in caustics at relatively high altitudes compared to the usual conal radio beams, and we allow both the minimum and maximum altitudes of the gamma-ray and radio emission regions to vary within a limited range (excluding the minimum gamma-ray altitude of the alTPC model, which is kept constant at the stellar radius, and that of the alOG model, which is set to the position-dependent null charge surface altitude). Alternatively, phase-aligned solutions also exist for emission originating near the stellar surface in a slot gap scenario (low-altitude slot gap (laSG) models). We find that the alTPC models provide slightly better LC fits than the alOG models, and both of these give better fits than the laSG models (for the limited range of parameters considered in the case of the laSG models). Thus, our fits imply that the phase-aligned LCs are likely of caustic origin, produced in the outer magnetosphere, and

  13. Light and Color Curve Properties of Type Ia Supernovae: Theory Versus Observations

    Hoeflich, P.; Hsiao, E. Y. [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Ashall, C. [Astrophysics Research Institute, Liverpool John Moore University, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Burns, C. R. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Diamond, T. R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Phillips, M. M. [Carnegie Observatories, Las Campanas Observatory, Casilla 601 La Serena (Chile); Sand, D. [Physics and Astronomy Department, Texas Tech University, Box 41051, Lubbock, TX 79409-1051 (United States); Stritzinger, M. D. [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000, Aarhus (Denmark); Suntzeff, N.; Krisciunas, K.; Wang, L. [The G.P. and C. Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States); Contreras, C.; Morrell, N., E-mail: phoeflich77@gmail.com [Departamento de Física, Universidad Técnica Federico Santa Maria, Ava España 1680, Casilla 110-V, Valparaiso (Chile)

    2017-09-01

    We study the optical light curve (LC) relations of Type Ia supernovae (SNe Ia) for their use in cosmology using high-quality photometry published by the Carnegie Supernova Project (CSP-I). We revisit the classical luminosity decline rate (Δ m {sub 15}) relation and the Lira relation, as well as investigate the time evolution of the ( B − V ) color and B ( B − V ), which serves as the basis of the color–stretch relation and Color–MAgnitude Intercept Calibrations (CMAGIC). Our analysis is based on explosion and radiation transport simulations for spherically symmetric delayed-detonation models (DDT) producing normal-bright and subluminous SNe Ia. Empirical LC relations can be understood as having the same physical underpinnings, i.e., opacities, ionization balances in the photosphere, and radioactive energy deposition changing with time from below to above the photosphere. Some three to four weeks past maximum, the photosphere recedes to {sup 56}Ni-rich layers of similar density structure, leading to a similar color evolution. An important secondary parameter is the central density ρ {sub c} of the WD because at higher densities, more electron-capture elements are produced at the expense of {sup 56}Ni production. This results in a Δ m {sub 15} spread of 0.1 mag in normal-bright and 0.7 mag in subluminous SNe Ia and ≈0.2 mag in the Lira relation. We show why color–magnitude diagrams emphasize the transition between physical regimes and enable the construction of templates that depend mostly on Δ m {sub 15} with little dispersion in both the CSP-I sample and our DDT models. This allows intrinsic SN Ia variations to be separated from the interstellar reddening characterized by E ( B − V ) and R {sub B}. Invoking different scenarios causes a wide spread in empirical relations, which may suggest one dominant scenario.

  14. THE LICK AGN MONITORING PROJECT 2011: SPECTROSCOPIC CAMPAIGN AND EMISSION-LINE LIGHT CURVES

    Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA, 92697-4575 (United States); Bennert, Vardha N. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States); Canalizo, Gabriela [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Filippenko, Alexei V.; Li, Weidong [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Gates, Elinor L. [Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Malkan, Matthew A.; Treu, Tommaso [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Pancoast, Anna [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Sand, David J. [Texas Tech University, Physics Department, Box 41051, Lubbock, TX 79409-1051 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Boulevard, Pasadena, CA 91109 (United States); Woo, Jong-Hak [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Assef, Roberto J. [Núcleo de Astronomía de la Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Bae, Hyun-Jin [Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of); Brewer, Brendon J. [Department of Statistics, The University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Cenko, S. Bradley [Astrophysics Science Division, NASA Goddard Space Flight Center, MC 661, Greenbelt, MD 20771 (United States); and others

    2015-04-15

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ width and luminosity, demonstrating that the broad-line region “breathes” on short timescales of days to weeks in response to continuum variations. We also find that broad Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ velocity shifted by ∼250 km s{sup −1} over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  15. CAN LARGE TIME DELAYS OBSERVED IN LIGHT CURVES OF CORONAL LOOPS BE EXPLAINED IN IMPULSIVE HEATING?

    Lionello, Roberto; Linker, Jon A.; Mikić, Zoran; Alexander, Caroline E.; Winebarger, Amy R.

    2016-01-01

    The light curves of solar coronal loops often peak first in channels associated with higher temperatures and then in those associated with lower temperatures. The delay times between the different narrowband EUV channels have been measured for many individual loops and recently for every pixel of an active region observation. The time delays between channels for an active region exhibit a wide range of values. The maximum time delay in each channel pair can be quite large, i.e., >5000 s. These large time delays make-up 3%–26% (depending on the channel pair) of the pixels where a trustworthy, positive time delay is measured. It has been suggested that these time delays can be explained by simple impulsive heating, i.e., a short burst of energy that heats the plasma to a high temperature, after which the plasma is allowed to cool through radiation and conduction back to its original state. In this paper, we investigate whether the largest observed time delays can be explained by this hypothesis by simulating a series of coronal loops with different heating rates, loop lengths, abundances, and geometries to determine the range of expected time delays between a set of four EUV channels. We find that impulsive heating cannot address the largest time delays observed in two of the channel pairs and that the majority of the large time delays can only be explained by long, expanding loops with photospheric abundances. Additional observations may rule out these simulations as an explanation for the long time delays. We suggest that either the time delays found in this manner may not be representative of real loop evolution, or that the impulsive heating and cooling scenario may be too simple to explain the observations, and other potential heating scenarios must be explored

  16. Light and Color Curve Properties of Type Ia Supernovae: Theory Versus Observations

    Hoeflich, P.; Hsiao, E. Y.; Ashall, C.; Burns, C. R.; Diamond, T. R.; Phillips, M. M.; Sand, D.; Stritzinger, M. D.; Suntzeff, N.; Krisciunas, K.; Wang, L.; Contreras, C.; Morrell, N.

    2017-01-01

    We study the optical light curve (LC) relations of Type Ia supernovae (SNe Ia) for their use in cosmology using high-quality photometry published by the Carnegie Supernova Project (CSP-I). We revisit the classical luminosity decline rate (Δ m 15 ) relation and the Lira relation, as well as investigate the time evolution of the ( B − V ) color and B ( B − V ), which serves as the basis of the color–stretch relation and Color–MAgnitude Intercept Calibrations (CMAGIC). Our analysis is based on explosion and radiation transport simulations for spherically symmetric delayed-detonation models (DDT) producing normal-bright and subluminous SNe Ia. Empirical LC relations can be understood as having the same physical underpinnings, i.e., opacities, ionization balances in the photosphere, and radioactive energy deposition changing with time from below to above the photosphere. Some three to four weeks past maximum, the photosphere recedes to 56 Ni-rich layers of similar density structure, leading to a similar color evolution. An important secondary parameter is the central density ρ c of the WD because at higher densities, more electron-capture elements are produced at the expense of 56 Ni production. This results in a Δ m 15 spread of 0.1 mag in normal-bright and 0.7 mag in subluminous SNe Ia and ≈0.2 mag in the Lira relation. We show why color–magnitude diagrams emphasize the transition between physical regimes and enable the construction of templates that depend mostly on Δ m 15 with little dispersion in both the CSP-I sample and our DDT models. This allows intrinsic SN Ia variations to be separated from the interstellar reddening characterized by E ( B − V ) and R B . Invoking different scenarios causes a wide spread in empirical relations, which may suggest one dominant scenario.

  17. Statistical improvement in detection level of gravitational microlensing events from their light curves

    Ibrahim, Ichsan; Malasan, Hakim L.; Kunjaya, Chatief; Timur Jaelani, Anton; Puannandra Putri, Gerhana; Djamal, Mitra

    2018-04-01

    In astronomy, the brightness of a source is typically expressed in terms of magnitude. Conventionally, the magnitude is defined by the logarithm of received flux. This relationship is known as the Pogson formula. For received flux with a small signal to noise ratio (S/N), however, the formula gives a large magnitude error. We investigate whether the use of Inverse Hyperbolic Sine function (hereafter referred to as the Asinh magnitude) in the modified formulae could allow for an alternative calculation of magnitudes for small S/N flux, and whether the new approach is better for representing the brightness of that region. We study the possibility of increasing the detection level of gravitational microlensing using 40 selected microlensing light curves from the 2013 and 2014 seasons and by using the Asinh magnitude. Photometric data of the selected events are obtained from the Optical Gravitational Lensing Experiment (OGLE). We found that utilization of the Asinh magnitude makes the events brighter compared to using the logarithmic magnitude, with an average of about 3.42 × 10‑2 magnitude and an average in the difference of error between the logarithmic and the Asinh magnitude of about 2.21 × 10‑2 magnitude. The microlensing events OB140847 and OB140885 are found to have the largest difference values among the selected events. Using a Gaussian fit to find the peak for OB140847 and OB140885, we conclude statistically that the Asinh magnitude gives better mean squared values of the regression and narrower residual histograms than the Pogson magnitude. Based on these results, we also attempt to propose a limit in magnitude value for which use of the Asinh magnitude is optimal with small S/N data.

  18. Real-time evaluation of two light delivery systems for photodynamic disinfection of Candida albicans biofilm in curved root canals.

    Sabino, C P; Garcez, A S; Núñez, S C; Ribeiro, M S; Hamblin, M R

    2015-08-01

    Antimicrobial photodynamic therapy (APDT) combined with endodontic treatment has been recognized as an alternative approach to complement conventional root canal disinfection methods on bacterial biofilms. We developed an in  vitro model of bioluminescent Candida albicans biofilm inside curved dental root canals and investigated the microbial reduction produced when different light delivery methods are employed. Each light delivery method was evaluated in respect to the light distribution provided inside curved root canals. After conventional endodontic preparation, teeth were sterilized before canals were contaminated by a bioluminescent strain of C. albicans (CEC789). Methylene blue (90 μM) was introduced into the canals and then irradiated (λ = 660 nm, P = 100 mW, beam diameter = 2 mm) with laser tip either in contact with pulp chamber or within the canal using an optical diffuser fiber. Light distribution was evaluated by CCD camera, and microbial reduction was monitored through bioluminescence imaging. Our findings demonstrated that the bioluminescent C. albicans biofilm model had good reproducibility and uniformity. Light distribution in dental tissue was markedly dependent on the light delivery system, and this strategy was directly related to microbial destruction. Both light delivery systems performed significant fungal inactivation. However, when irradiation was performed with optical diffuser fiber, microbial burden reduction was nearly 100 times more effective. Bioluminescence is an interesting real-time analysis to endodontic C. albicans biofilm inactivation. APDT showed to be an effective way to inactivate C. albicans biofilms. Diffuser fibers provided optimized light distribution inside curved root canals and significantly increased APDT efficiency.

  19. High-Precision Mass Measurements of Exotic Nuclei with the Triple-Trap Mass Spectrometer Isoltrap

    Blaum, K; Zuber, K T; Stanja, J

    2002-01-01

    The masses of close to 200 short-lived nuclides have already been measured with the mass spectrometer ISOLTRAP with a relative precision between 1$\\times$10$^{-7}$ and 1$\\times$10^{-8}$. The installatin of a radio-frequency quadrupole trap increased the overall efficiency by two orders of magnitude which is at present about 1%. In a recent upgrade, we installed a carbon cluster laser ion source, which will allow us to use carbon clusters as mass references for absolute mass measurements. Due to these improvements and the high reliability of ISOLTRAP we are now able to perform accurate high-precision mass measurements all over the nuclear chart. We propose therefore mass measurements on light, medium and heavy nuclides on both sides of the valley of stability in the coming four years. ISOLTRAP is presently the only instrument capable of the high precision required for many of the proposed studies.

  20. Strategy for Realizing High-Precision VUV Spectro-Polarimeter

    Ishikawa, R.; Narukage, N.; Kubo, M.; Ishikawa, S.; Kano, R.; Tsuneta, S.

    2014-12-01

    Spectro-polarimetric observations in the vacuum ultraviolet (VUV) range are currently the only means to measure magnetic fields in the upper chromosphere and transition region of the solar atmosphere. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) aims to measure linear polarization at the hydrogen Lyman- α line (121.6 nm). This measurement requires a polarization sensitivity better than 0.1 %, which is unprecedented in the VUV range. We here present a strategy with which to realize such high-precision spectro-polarimetry. This involves the optimization of instrument design, testing of optical components, extensive analyses of polarization errors, polarization calibration of the instrument, and calibration with onboard data. We expect that this strategy will aid the development of other advanced high-precision polarimeters in the UV as well as in other wavelength ranges.

  1. Weak gravitational lensing towards high-precision cosmology

    Berge, Joel

    2007-01-01

    This thesis aims at studying weak gravitational lensing as a tool for high-precision cosmology. We first present the development and validation of a precise and accurate tool for measuring gravitational shear, based on the shapelets formalism. We then use shapelets on real images for the first time, we analyze CFHTLS images, and combine them with XMM-LSS data. We measure the normalisation of the density fluctuations power spectrum σ 8 , and the one of the mass-temperature relation for galaxy clusters. The analysis of the Hubble space telescope COSMOS field confirms our σ 8 measurement and introduces tomography. Finally, aiming at optimizing future surveys, we compare the individual and combined merits of cluster counts and power spectrum tomography. Our results demonstrate that next generation surveys will allow weak lensing to yield its full potential in the high-precision cosmology era. (author) [fr

  2. High precision frequency estimation for harpsichord tuning classification

    Tidhar, D.; Mauch, M.; Dixon, S.

    2010-01-01

    We present a novel music signal processing task of classifying the tuning of a harpsichord from audio recordings of standard musical works. We report the results of a classification experiment involving six different temperaments, using real harpsichord recordings as well as synthesised audio data. We introduce the concept of conservative transcription, and show that existing high-precision pitch estimation techniques are sufficient for our task if combined with conservative transcription. In...

  3. System and method for high precision isotope ratio destructive analysis

    Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

    2013-07-02

    A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

  4. High precision straw tube chamber with cathode readout

    Bychkov, V.N.; Golutvin, I.A.; Ershov, Yu.V.

    1992-01-01

    The high precision straw chamber with cathode readout was constructed and investigated. The 10 mm straws were made of aluminized mylar strip with transparent longitudinal window. The X coordinate information has been taken from the cathode strips as induced charges and investigated via centroid method. The spatial resolution σ=120 μm has been obtained with signal/noise ratio about 60. The possible ways for improving the signal/noise ratio have been described. 7 refs.; 8 figs

  5. A high precision straw tube chamber with cathode readout

    Bychkov, V.N.; Golutvin, I.A.; Ershov, Yu.V.; Zubarev, E.V.; Ivanov, A.B.; Lysiakov, V.N.; Makhankov, A.V.; Movchan, S.A.; Peshekhonov, V.D.; Preda, T.

    1993-01-01

    The high precision straw chamber with cathode readout was constructed and investigated. The 10 mm diameter straws were made of aluminized Mylar with transparent longitudinal window. The X-coordinate information has been taken from cathode strips as induced charges and investigated with the centroid method. The spatial resolution σ x =103 μm was obtained at a signal-to-noise ratio of about 70. The possible ways to improve the signal-to-noise ratio are discussed. (orig.)

  6. An Empirical Fitting Method for Type Ia Supernova Light Curves: A Case Study of SN 2011fe

    Zheng, WeiKang; Filippenko, Alexei V., E-mail: zwk@astro.berkeley.edu [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2017-03-20

    We present a new empirical fitting method for the optical light curves of Type Ia supernovae (SNe Ia). We find that a variant broken-power-law function provides a good fit, with the simple assumption that the optical emission is approximately the blackbody emission of the expanding fireball. This function is mathematically analytic and is derived directly from the photospheric velocity evolution. When deriving the function, we assume that both the blackbody temperature and photospheric velocity are constant, but the final function is able to accommodate these changes during the fitting procedure. Applying it to the case study of SN 2011fe gives a surprisingly good fit that can describe the light curves from the first-light time to a few weeks after peak brightness, as well as over a large range of fluxes (∼5 mag, and even ∼7 mag in the g band). Since SNe Ia share similar light-curve shapes, this fitting method has the potential to fit most other SNe Ia and characterize their properties in large statistical samples such as those already gathered and in the near future as new facilities become available.

  7. ASTEROID LIGHT CURVES FROM THE PALOMAR TRANSIENT FACTORY SURVEY: ROTATION PERIODS AND PHASE FUNCTIONS FROM SPARSE PHOTOMETRY

    Waszczak, Adam [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Chang, Chan-Kao; Cheng, Yu-Chi; Ip, Wing-Huen; Kinoshita, Daisuke [Institute of Astronomy, National Central University, Jhongli, Taiwan (China); Ofek, Eran O. [Benoziyo Center for Astrophysics, Weizmann Institute of Science, Rehovot (Israel); Laher, Russ; Surace, Jason [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Masci, Frank; Helou, George [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Levitan, David; Prince, Thomas A.; Kulkarni, Shrinivas, E-mail: waszczak@caltech.edu [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-09-15

    We fit 54,296 sparsely sampled asteroid light curves in the Palomar Transient Factory survey to a combined rotation plus phase-function model. Each light curve consists of 20 or more observations acquired in a single opposition. Using 805 asteroids in our sample that have reference periods in the literature, we find that the reliability of our fitted periods is a complicated function of the period, amplitude, apparent magnitude, and other light-curve attributes. Using the 805-asteroid ground-truth sample, we train an automated classifier to estimate (along with manual inspection) the validity of the remaining ∼53,000 fitted periods. By this method we find that 9033 of our light curves (of ∼8300 unique asteroids) have “reliable” periods. Subsequent consideration of asteroids with multiple light-curve fits indicates a 4% contamination in these “reliable” periods. For 3902 light curves with sufficient phase-angle coverage and either a reliable fit period or low amplitude, we examine the distribution of several phase-function parameters, none of which are bimodal though all correlate with the bond albedo and with visible-band colors. Comparing the theoretical maximal spin rate of a fluid body with our amplitude versus spin-rate distribution suggests that, if held together only by self-gravity, most asteroids are in general less dense than ∼2 g cm{sup −3}, while C types have a lower limit of between 1 and 2 g cm{sup −3}. These results are in agreement with previous density estimates. For 5–20 km diameters, S types rotate faster and have lower amplitudes than C types. If both populations share the same angular momentum, this may indicate the two types’ differing ability to deform under rotational stress. Lastly, we compare our absolute magnitudes (and apparent-magnitude residuals) to those of the Minor Planet Center’s nominal (G = 0.15, rotation-neglecting) model; our phase-function plus Fourier-series fitting reduces asteroid photometric rms

  8. Supernovae with two peaks in the optical light curve and the signature of progenitors with low-mass extended envelopes

    Nakar, Ehud [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Piro, Anthony L. [Theoretical Astrophysics, California Institute of Technology, 1200 East California Boulevard, M/C 350-17, Pasadena, CA 91125 (United States)

    2014-06-20

    Early observations of supernova light curves are powerful tools for shedding light on the pre-explosion structures of their progenitors and their mass-loss histories just prior to explosion. Some core-collapse supernovae that are detected during the first days after the explosion prominently show two peaks in the optical bands, including the R and I bands, where the first peak appears to be powered by the cooling of shocked surface material and the second peak is clearly powered by radioactive decay. Such light curves have been explored in detail theoretically for SN 1993J and 2011dh, where it was found that they may be explained by progenitors with extended, low-mass envelopes. Here, we generalize these results. We first explore whether any double-peaked light curve of this type can be generated by a progenitor with a 'standard' density profile, such as a red supergiant or a Wolf-Rayet star. We show that a standard progenitor (1) cannot produce a double-peaked light curve in the R and I bands and (2) cannot exhibit a fast drop in the bolometric luminosity as is seen after the first peak. We then explore the signature of a progenitor with a compact core surrounded by extended, low-mass material. This may be a hydrostatic low-mass envelope or material ejected just prior to the explosion. We show that it naturally produces both of these features. We use this result to provide simple formulae to estimate (1) the mass of the extended material from the time of the first peak, (2) the extended material radius from the luminosity of the first peak, and (3) an upper limit on the core radius from the luminosity minimum between the two peaks.

  9. Effects of forward and backward transitions in light intensities in tau-illuminance curves of the rat motor activity rhythm under constant dim light.

    Cambras, Trinitat; Díez-Noguera, Antoni

    2012-07-01

    Circadian rhythms are strongly influenced by light intensity, the effects of which may persist beyond the duration of light exposure (aftereffects). Here, the authors constructed period-illuminance curves for the motor activity circadian rhythm of male and female rats by recording the effects of a series of small upward and downward steps in light intensity (illuminance ranging between .01 lux of dim red light and 1 lux of white light) on their activity. In all cases, stepwise changes were made in five logarithmic steps (irradiance: dim red light: .692 µW/cm(2) and white light: .006, .016, .044, .12, and .315 µW/cm(2), corresponding, respectively, to .02, .05, .14, .13, and 1 lux measured at cage level), with changes in intensity every 2 wks. One group of rats (DLD) started in dim red light, moved up to 1 lux white light, and then back down to the original light intensity. Another group (LDL) started at 1 lux, moved down to .01 lux, and then back up to the original intensity. Motor activity data were recorded throughout the experiment and tau values, the percentage of variance explained by the rhythm, and the mean motor activity for each stage and group were calculated. The results show differences in the dynamics of tau values between the DLD and LDL groups and between males and females. In the LDL group, the tau values of both males and females were dependent on light intensity, and were similar for the forward and backward transitions. In other words, no aftereffects were found, and no differences were detected between males and females. In the DLD group, however, differences were found between males and females. Males had a tau value of 24 h 20 min under dim red light, 25 h 40 min under 1 lux, and 24 h 50 min on return to dim red light. It is noticeable that the tau values of the backward branch of the illuminance curve contradicted classical predictions, since at .38 and .14 lux the tau values were shorter than those found under the same intensities after

  10. CHARACTERIZATION OF THE X-RAY LIGHT CURVE OF THE {gamma} Cas-LIKE B1e STAR HD 110432

    Smith, Myron A. [Catholic University of America, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lopes de Oliveira, Raimundo [Departamento de Fisica, Universidade Federal de Sergipe, Av. Marechal Rondon s/n, 49100-000 Sao Cristovao, SE (Brazil); Motch, Christian, E-mail: msmith@stsci.edu [Observatoire Astronomique, Universite de Strasbourg, CNRS UMR 7550, 11 rue de l' Universite, F-67000 Strasbourg (France)

    2012-08-10

    HD 110432 (BZ Cru; B1Ve) is the brightest member of a small group of '{gamma} Cas analogs' that emit copious hard X-ray flux, punctuated by ubiquitous 'flares'. To characterize the X-ray time history of this star, we made a series of six RXTE multi-visit observations in 2010 and an extended observation with the XMM-Newton in 2007. We analyzed these new light curves along with three older XMM-Newton observations from 2002 to 2003. Distributed over five months, the RXTE observations were designed to search for long X-ray modulations over a few months. These observations indeed suggest the presence of a long cycle with P Almost-Equal-To 226 days and an amplitude of a factor of two. We also used X-ray light curves constructed from XMM-Newton observations to characterize the lifetimes, strengths, and interflare intervals of 1615 flare-like events in the light curves. After accounting for false positive events, we infer the presence of 955 (2002-2003) and 386 (2007) events we identified as flares. Similarly, as a control we measured the same attributes for an additional group of 541 events in XMM-Newton light curves of {gamma} Cas, which, after a similar correction, yielded 517 flares. We found that the flare properties of HD 110432 are mostly similar to our control group. In both cases the distribution of flare strengths are best fit with log-linear relations. Both the slopes of these distributions and the flaring frequencies themselves exhibit modest fluctuations. We discovered that some flares in the hard X-ray band of HD 110432 were weak or unobserved in the soft band and vice versa. The light curves also occasionally show rapid curve drop-offs that are sustained for hours. We discuss the existence of the long cycle and these flare properties in the backdrop of two rival scenarios to produce hard X-rays, a magnetic star-disk interaction, and the accretion of blobs onto a secondary white dwarf.

  11. Light curve of the CX Cep eclipsing binary system and characteristics of a Wolf-Rayet star

    Lipunova, N.A.; Cherepashchuk, A.M.

    1982-01-01

    The photoelectric B, V, R observations of the eclipsing Wolf-Rayet binary CX Cep (WN 5 + 08V, V approximately equal to 12sup(m),1, p approximately equal to 2sup(d),127) have been carried out. The physical characteristics of the WN 5 star, the core radius r 0 =(4.5+-2.5) Rsub(S) (Rsub(S) is the Sun radius) and the brightness temperature of the core Tsub(b)>50 000 K, are determined from the analysis of the light curve lambdasub(eff) approximately equal to 6 000 A. These characteristics are close to those of the WN 5 star in the eclipsing Wolf-Rayet binary V 444 Cyg. The results of the interpretation of the light curves of two eclipsing Wolf-Rayet binaries (V 444 Cyg and CX Cep) confirm the conclusions of the modern theory of evolution of massive close binary systems [ru

  12. An adaptive-binning method for generating constant-uncertainty/constant-significance light curves with Fermi-LAT data

    Lott, B.; Escande, L.; Larsson, S.; Ballet, J.

    2012-01-01

    Here, we present a method enabling the creation of constant-uncertainty/constant-significance light curves with the data of the Fermi-Large Area Telescope (LAT). The adaptive-binning method enables more information to be encapsulated within the light curve than with the fixed-binning method. Although primarily developed for blazar studies, it can be applied to any sources. Furthermore, this method allows the starting and ending times of each interval to be calculated in a simple and quick way during a first step. The reported mean flux and spectral index (assuming the spectrum is a power-law distribution) in the interval are calculated via the standard LAT analysis during a second step. In the absence of major caveats associated with this method Monte-Carlo simulations have been established. We present the performance of this method in determining duty cycles as well as power-density spectra relative to the traditional fixed-binning method.

  13. Non-regularized inversion method from light scattering applied to ferrofluid magnetization curves for magnetic size distribution analysis

    Rijssel, Jos van; Kuipers, Bonny W.M.; Erné, Ben H.

    2014-01-01

    A numerical inversion method known from the analysis of light scattering by colloidal dispersions is now applied to magnetization curves of ferrofluids. The distribution of magnetic particle sizes or dipole moments is determined without assuming that the distribution is unimodal or of a particular shape. The inversion method enforces positive number densities via a non-negative least squares procedure. It is tested successfully on experimental and simulated data for ferrofluid samples with known multimodal size distributions. The created computer program MINORIM is made available on the web. - Highlights: • A method from light scattering is applied to analyze ferrofluid magnetization curves. • A magnetic size distribution is obtained without prior assumption of its shape. • The method is tested successfully on ferrofluids with a known size distribution. • The practical limits of the method are explored with simulated data including noise. • This method is implemented in the program MINORIM, freely available online

  14. Gamma-ray pulsar physics: gap-model populations and light-curve analyses in the Fermi era

    Pierbattista, M.

    2010-01-01

    This thesis research focusses on the study of the young and energetic isolated ordinary pulsar population detected by the Fermi gamma-ray space telescope. We compared the model expectations of four emission models and the LAT data. We found that all the models fail to reproduce the LAT detections, in particular the large number of high E objects observed. This inconsistency is not model dependent. A discrepancy between the radio-loud/radio-quiet objects ratio was also found between the observed and predicted samples. The L γ α E 0.5 relation is robustly confirmed by all the assumed models with particular agreement in the slot gap (SG) case. On luminosity bases, the intermediate altitude emission of the two pole caustic SG model is favoured. The beaming factor f Ω shows an E dependency that is slightly visible in the SG case. Estimates of the pulsar orientations have been obtained to explain the simultaneous gamma and radio light-curves. By analysing the solutions we found a relation between the observed energy cutoff and the width of the emission slot gap. This relation has been theoretically predicted. A possible magnetic obliquity α alignment with time is rejected -for all the models- on timescale of the order of 10 6 years. The light-curve morphology study shows that the outer magnetosphere gap emission (OGs) are favoured to explain the observed radio-gamma lag. The light curve moment studies (symmetry and sharpness) on the contrary favour a two pole caustic SG emission. All the model predictions suggest a different magnetic field layout with an hybrid two pole caustic and intermediate altitude emission to explain both the pulsar luminosity and light curve morphology. The low magnetosphere emission mechanism of the polar cap model, is systematically rejected by all the tests done. (author) [fr

  15. VizieR Online Data Catalog: SNe II light curves & spectra from the CfA (Hicken+, 2017)

    Hicken, M.; Friedman, A. S.; Blondin, S.; Challis, P.; Berlind, P.; Calkins, M.; Esquerdo, G.; Matheson, T.; Modjaz, M.; Rest, A.; Kirshner, R. P.

    2018-01-01

    Since all of the optical photometry reported here was produced as part of the CfA3 and CfA4 processing campaigns, see Hicken+ (2009, J/ApJ/700/331) and Hicken+ (2012, J/ApJS/200/12) for greater details on the instruments, observations, photometry pipeline, calibration, and host-galaxy subtraction used to create the CfA SN II light curves. (8 data files).

  16. The frequency content of Double-Mode Cepheids light curves and the importance of the cross-coupling terms

    Poretti, Ennio

    1997-01-01

    The recent results (Pardo & Poretti 1997, A&A 324, 121; Poretti & Pardo 1997, A&A 324, 133) obtained on the frequency content of Double-Mode Cepheids light curves and the properties of their Fourier parameters are reviewed. Some points briefly discussed in previous papers (no third periodicity, methodological aspects on the true peaks detection, the action of the cross coupling terms and the impact on theoretical models) are described.

  17. The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0

    Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Holoien, T. W.-S.; Thompson, Todd A.; Prieto, J. L.; Dong, Subo; Shields, J. V.; Will, D.; Britt, C.; Perzanowski, D.; Pojmański, G.

    2017-10-01

    The All-Sky Automated Survey for Supernovae (ASAS-SN) is working toward imaging the entire visible sky every night to a depth of V˜ 17 mag. The present data covers the sky and spans ˜2-5 years with ˜100-400 epochs of observation. The data should contain some ˜1 million variable sources, and the ultimate goal is to have a database of these observations publicly accessible. We describe here a first step, a simple but unprecedented web interface https://asas-sn.osu.edu/ that provides an up to date aperture photometry light curve for any user-selected sky coordinate. The V band photometry is obtained using a two-pixel (16.″0) radius aperture and is calibrated against the APASS catalog. Because the light curves are produced in real time, this web tool is relatively slow and can only be used for small samples of objects. However, it also imposes no selection bias on the part of the ASAS-SN team, allowing the user to obtain a light curve for any point on the celestial sphere. We present the tool, describe its capabilities, limitations, and known issues, and provide a few illustrative examples.

  18. Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

    Kovačević, Andjelka B.; Pérez-Hernández, Ernesto; Popović, Luka Č.; Shapovalova, Alla I.; Kollatschny, Wolfram; Ilić, Dragana

    2018-04-01

    New combined data of five well-known type 1 active galactic nuclei (AGNs) are probed with a novel hybrid method in a search for oscillatory behaviour. Additional analysis of artificial light curves obtained from the coupled oscillatory models gives confirmation for detected periods that could have a physical background. We find periodic variations in the long-term light curves of 3C 390.3, NGC 4151 and NGC 5548, and E1821 + 643, with correlation coefficients larger than 0.6. We show that the oscillatory patterns of two binary black hole candidates, NGC 5548 and E1821 + 643, correspond to qualitatively different dynamical regimes of chaos and stability, respectively. We demonstrate that the absence of oscillatory patterns in Arp 102B could be the result of a weak coupling between oscillatory mechanisms. This is the first good evidence that 3C 390.3 and Arp 102B, categorized as double-peaked Balmer line objects, have qualitative different dynamics. Our analysis shows a novelty in the oscillatory dynamical patterns of the light curves of these type 1 AGNs.

  19. PyTranSpot: A tool for multiband light curve modeling of planetary transits and stellar spots

    Juvan, Ines G.; Lendl, M.; Cubillos, P. E.; Fossati, L.; Tregloan-Reed, J.; Lammer, H.; Guenther, E. W.; Hanslmeier, A.

    2018-02-01

    Several studies have shown that stellar activity features, such as occulted and non-occulted starspots, can affect the measurement of transit parameters biasing studies of transit timing variations and transmission spectra. We present PyTranSpot, which we designed to model multiband transit light curves showing starspot anomalies, inferring both transit and spot parameters. The code follows a pixellation approach to model the star with its corresponding limb darkening, spots, and transiting planet on a two dimensional Cartesian coordinate grid. We combine PyTranSpot with a Markov chain Monte Carlo framework to study and derive exoplanet transmission spectra, which provides statistically robust values for the physical properties and uncertainties of a transiting star-planet system. We validate PyTranSpot's performance by analyzing eleven synthetic light curves of four different star-planet systems and 20 transit light curves of the well-studied WASP-41b system. We also investigate the impact of starspots on transit parameters and derive wavelength dependent transit depth values for WASP-41b covering a range of 6200-9200 Å, indicating a flat transmission spectrum.

  20. The X-Ray Light Curve of the Very Luminous Supernova SN 1978K in NGC 1313

    Schlegel, Eric M.; Petre, R.; Colbert, E. J. M.

    1996-01-01

    We present the 0.5-2.0 keV light curve of the X-ray luminous supernova SN 1978K in NGC 1313, based on six ROSAT observations spanning 1990 July to t994 July. SN 1978K is one of a few supernovae or supernova remnants that are very luminous (˜1039-1040 ergs s-1) in the X-ray, optical, and radio bands, and the first, at a supernova age of 10-20 yr, for which sufficient data exist to create an X-ray light curve. The X-ray flux is approximately constant over the 4 yr sampled by our observations, which were obtained 12-16 yr after the initial explosion. Three models exist to explain the large X-ray luminosity: pulsar input, a reverse shock running back into the expanding debris of the supernova, and the outgoing shock crushing of cloudlets in the debris field. Based upon calculations of Chevalier & Fransson, a pulsar cannot provide sufficient energy to produce the soft X-ray luminosity. Based upon the models and the light curve to date, it is not possible to discern the evolutionary phase of the supernova.

  1. Design and algorithm research of high precision airborne infrared touch screen

    Zhang, Xiao-Bing; Wang, Shuang-Jie; Fu, Yan; Chen, Zhao-Quan

    2016-10-01

    There are shortcomings of low precision, touch shaking, and sharp decrease of touch precision when emitting and receiving tubes are failure in the infrared touch screen. A high precision positioning algorithm based on extended axis is proposed to solve these problems. First, the unimpeded state of the beam between emitting and receiving tubes is recorded as 0, while the impeded state is recorded as 1. Then, the method of oblique scan is used, in which the light of one emitting tube is used for five receiving tubes. The impeded information of all emitting and receiving tubes is collected as matrix. Finally, according to the method of arithmetic average, the position of the touch object is calculated. The extended axis positioning algorithm is characteristic of high precision in case of failure of individual infrared tube and affects slightly the precision. The experimental result shows that the 90% display area of the touch error is less than 0.25D, where D is the distance between adjacent emitting tubes. The conclusion is gained that the algorithm based on extended axis has advantages of high precision, little impact when individual infrared tube is failure, and using easily.

  2. Design of High-Precision Infrared Multi-Touch Screen Based on the EFM32

    Zhong XIAOLING

    2014-07-01

    Full Text Available Due to the low accuracy of traditional infrared multi-touch screen, it’s difficult to ascertain the touch point. Putting forward a design scheme based on ARM Cortex-M3 kernel EFM32 processor of high precision infrared multi-touch screen. Using tracking scanning area algorithm after accessed electricity for the first time to scan, it greatly improved the scanning efficiency and response speed. Based on the infrared characteristic difference, putting forward a data fitting algorithm, employing the subtraction relationship between the covering area and sampling value to curve fitting, concluding the infrared sampling value of subtraction characteristic curve, establishing a sampling value differential data tables, at last ensuring the precise location of touch point. Besides, practices have proved that the accuracy of the infrared touch screen can up to 0.5 mm. The design uses standard USB port which connected to the PC can also be widely used in various terminals.

  3. Preparing for TESS: Precision Ground-based Light-curves of Newly Discovered Transiting Exoplanets

    Li, Yiting; Stefansson, Gudmundur; Mahadevan, Suvrath; Monson, Andy; Hebb, Leslie; Wisniewski, John; Huehnerhoff, Joseph

    2018-01-01

    NASA’s Transiting Exoplanet Survey Satellite (TESS), to be launched in early 2018, is expected to catalog a myriad of transiting exoplanet candidates ranging from Earth-sized to gas giants, orbiting a diverse range of stellar types in the solar neighborhood. In particular, TESS will find small planets orbiting the closest and brightest stars, and will enable detailed atmospheric characterizations of planets with current and future telescopes. In the TESS era, ground-based follow-up resources will play a critical role in validating and confirming the planetary nature of the candidates TESS will discover. Along with confirming the planetary nature of exoplanet transits, high precision ground-based transit observations allow us to put further constraints on exoplanet orbital parameters and transit timing variations. In this talk, we present new observations of transiting exoplanets recently discovered by the K2 mission, using the optical diffuser on the 3.5m ARC Telescope at Apache Point Observatory. These include observations of the mini-Neptunes K2-28b and K2-104b orbiting early-to-mid M-dwarfs. In addition, other recent transit observations performed using the robotic 30cm telescope at Las Campanas Observatory in Chile will be presented.

  4. High-precision ground-based photometry of exoplanets

    de Mooij Ernst J.W.

    2013-04-01

    Full Text Available High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana. The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level, this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

  5. Helical Tomography of an Accretion Disk by Superhump Light Curves of the 2001 Outburst of WZ Sagittae

    Osaki, Yoji

    2003-06-01

    A new method for analyzing complex superhump light curves for the 2001 outburst of WZ Sagittae is proposed. The complexity arises because intrinsically time-varying and non-axisymmetric distributions of superhump light sources are coupled with the aspect effects around the binary orbital phase because of its high orbital inclination. The new method can disentangle these complexities by separating the non-axisymmetric spatial distribution in the disk from the time variation with the superhump period. It may be called a helical tomography of an accretion disk because it can reconstruct a series of disk images (i.e., disk's azimuthal structures) at different superhump phases. The power spectral data of superhump light curves of the 2001 outburst of WZ Sge by Patterson et al. (2002, PASP, 114, 721) are now interpreted under a new light based on the concept of helical tomography, and the azimuthal wave numbers of various frequency modes are identified. In particular, a frequen! cy component, nω0 - Ω, where ω0 and Ω are the orbital frequency and a low frequency of the apsidal precession of the eccentric disk, is understood as an (n - 1)-armed traveling wave in the disk. A vigorous excitation of a wave component of cos(2Θ - 3ω0t) in the first week of the superhump era of WZ Sge, where Θ is the azimuthal angle, supports Lubow's (1991, AAA 54.064.175) theory of non-linear wave coupling of the eccentric Lindblad resonance for the superhump phenomenon. This method can in principle be applied to other SU UMa stars with high orbital inclination if light curves are fully covered over the beat cycle.

  6. High-precision micro/nano-scale machining system

    Kapoor, Shiv G.; Bourne, Keith Allen; DeVor, Richard E.

    2014-08-19

    A high precision micro/nanoscale machining system. A multi-axis movement machine provides relative movement along multiple axes between a workpiece and a tool holder. A cutting tool is disposed on a flexible cantilever held by the tool holder, the tool holder being movable to provide at least two of the axes to set the angle and distance of the cutting tool relative to the workpiece. A feedback control system uses measurement of deflection of the cantilever during cutting to maintain a desired cantilever deflection and hence a desired load on the cutting tool.

  7. Strategies for high-precision Global Positioning System orbit determination

    Lichten, Stephen M.; Border, James S.

    1987-01-01

    Various strategies for the high-precision orbit determination of the GPS satellites are explored using data from the 1985 GPS field test. Several refinements to the orbit determination strategies were found to be crucial for achieving high levels of repeatability and accuracy. These include the fine tuning of the GPS solar radiation coefficients and the ground station zenith tropospheric delays. Multiday arcs of 3-6 days provided better orbits and baselines than the 8-hr arcs from single-day passes. Highest-quality orbits and baselines were obtained with combined carrier phase and pseudorange solutions.

  8. High-precision multi-node clock network distribution.

    Chen, Xing; Cui, Yifan; Lu, Xing; Ci, Cheng; Zhang, Xuesong; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2017-10-01

    A high precision multi-node clock network for multiple users was built following the precise frequency transmission and time synchronization of 120 km fiber. The network topology adopts a simple star-shaped network structure. The clock signal of a hydrogen maser (synchronized with UTC) was recovered from a 120 km telecommunication fiber link and then was distributed to 4 sub-stations. The fractional frequency instability of all substations is in the level of 10 -15 in a second and the clock offset instability is in sub-ps in root-mean-square average.

  9. Future high precision experiments and new physics beyond Standard Model

    Luo, Mingxing.

    1993-01-01

    High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here

  10. Designing compensator of dual servo system for high precision positioning

    Choi, Hyeun Seok; Song, Chi Woo; Han, Chang Soo; Choi, Tae Hoon; Lee, Nak Kyu; Na, Kyung Hwan

    2003-01-01

    The high precision positioning mechanism is used in various industrial fields. It is used in semiconductor manufacturing line, test instrument, bioengineering, and MEMS and so on. This paper presents a positioning mechanism with dual servo system. Dual servo system consists of a coarse stage and a fine motion stage. The course stage is driven by VCM and the actuator of fine stage is the PZT. The purposes of dual servo system are stability, higher bandwidth, and robustness. Lead compensator is applied to this control system, and is designed by PQ method. Designed compensator can improve property of positioning mechanism

  11. International workshop on advanced materials for high precision detectors. Proceedings

    Nicquevert, B.; Hauviller, C.

    1994-01-01

    These proceedings gather together the contributions to the Workshop on Advanced Materials for High Precision Detectors, which was held from 28-30 September 1994 in Archamps, Haute-Savoie, France. This meeting brought together international experts (researchers, physicists and engineers) in the field of advanced materials and their use in high energy physics detectors or spacecraft applications. Its purpose was to discuss the status of the different materials currently in use in the structures of detectors and spacecraft, together with their actual performances, technological implications and future prospects. Environmental effects, such as those of moisture and radiation, were discussed, as were design and manufacturing technologies. Some case studies were presented. (orig.)

  12. B and V photoelectric photometry and light curve solution of the interacting binary systems HI Puppis, BL Eridani and SY Horologii

    Kern, J.R.

    1985-01-01

    The first photoelectric observations of the eclipsing binary systems HI Puppis, BL Eridani, and SY Horologii were obtained and complete B and V light curves are presented. Improved light elements were derived for all three systems. The light curves of HI Puppis were analyzed by the three different computer models of Wilson and Devinney (1971), Binnendijk (1977), and Wood (1971) to get the geometrical and photometric elements of the system. HI Puppis, whose light curves show a total eclipse at secondary minimum, is shown to be a classic A-Type W Ursae Majoris system. The geometrical and photometric elements of BL Eridani were obtained from the analysis of the light curves using the method of Wilson and Devinney. The asymmetric nature of the light curve is treated as being due to the presence of an underluminous starspot on the primary component. The light curves of BL Eri show secondary eclipse to be total. The system is found to be a near contact system with the primary component filling its Roche lobe and the secondary nearly filling its lobe with a fill-out ratio of approximately 1.0. The light curves of SY Horologii were also subjected to the model of Wilson and Devinney. Both primary and secondary eclipses are partial

  13. The effect of scattered light sensor orientation on roughness measurement of curved polished surfaces

    Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

    directions, and its acquisition within ± 16º angular range with a linear detector array. From the distribution of the acquired scattered light intensity, a number of statistical parameters describing the surface texture are calculated, where the Aq parameter (variance of the scattered light distribution...

  14. High Precision Edge Detection Algorithm for Mechanical Parts

    Duan Zhenyun

    2018-04-01

    Full Text Available High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.

  15. Present status and future aspects of highly precise radiotherapy

    Oita, Masataka; Takegawa, Yoshihiro; Maezawa, Hiroshi; Ikushima, Hitoshi; Osaki, Kyosuke; Nishitani, Hiromu

    2006-01-01

    This review describes about therapeutic equipments, irradiation technology, actual practice of highly precise radiotherapy (RT) and its tasks in future. Development of radiation equipments has made the therapy highly precise. At present, there are reportedly 836 linacs and 23 microtrons in Japan (March, 2005), most of which are computerized, new generation equipments. Image-guided RT, CT-linac system, real-time tumor-tracking RT (RTRT), tomotherapy and cyberknife are introduced owing to development of concerned devices and equipments. In addition, there are 7 facilities with proton and/or heavy ion beams. In parallel with the machine development above, irradiation has become to that from 2D to 3D by multi-gate technique with use of multi-leaf collimator and intensity-modulated RT is introduced. RTRT is an example of 4D RT. Practically, stereotactic irradiation (STI) to brain tumor has resulted in 1-year cumulative survival rate of 58% in 16 cases (23 foci, median size 1.2 cm and volume 0.57 ml) with median dose of 21.0 Gy in authors' hospital. STI in the early stage lung cancers is also practically conducted without severe adverse effects. Future tasks involve the further development of irradiation techniques and RT planning, QA/QC system, and raising of experts in related fields, which is a national problem. (T.I.)

  16. High Precision Edge Detection Algorithm for Mechanical Parts

    Duan, Zhenyun; Wang, Ning; Fu, Jingshun; Zhao, Wenhui; Duan, Boqiang; Zhao, Jungui

    2018-04-01

    High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.

  17. High precision capacitive beam phase probe for KHIMA project

    Hwang, Ji-Gwang, E-mail: windy206@hanmail.net [Korea Institute of Radiological and Medical Sciences, 215–4, Gongneung-dong, Nowon-t, Seoul 139–706 (Korea, Republic of); Yang, Tae-Keun [Korea Institute of Radiological and Medical Sciences, 215–4, Gongneung-dong, Nowon-t, Seoul 139–706 (Korea, Republic of); Forck, Peter [GSI Helmholtz Centre for Ion Research, Darmstadt 64291, German (Germany)

    2016-11-21

    In the medium energy beam transport (MEBT) line of KHIMA project, a high precision beam phase probe monitor is required for a precise tuning of RF phase and amplitude of Radio Frequency Quadrupole (RFQ) accelerator and IH-DTL linac. It is also used for measuring a kinetic energy of ion beam by time-of-flight (TOF) method using two phase probes. The capacitive beam phase probe has been developed. The electromagnetic design of the high precision phase probe was performed to satisfy the phase resolution of 1° (@200 MHz). It was confirmed by the test result using a wire test bench. The measured phase accuracy of the fabricated phase probe is 1.19 ps. The pre-amplifier electronics with the 0.125 ∼ 1.61 GHz broad-band was designed and fabricated for amplifying the signal strength. The results of RF frequency and beam energy measurement using a proton beam from the cyclotron in KIRAMS is presented.

  18. High-Precision Computation: Mathematical Physics and Dynamics

    Bailey, D.H.; Barrio, R.; Borwein, J.M.

    2010-01-01

    At the present time, IEEE 64-bit oating-point arithmetic is suficiently accurate for most scientic applications. However, for a rapidly growing body of important scientic computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion e ort. This pa- per presents a survey of recent applications of these techniques and provides someanalysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, studies of the one structure constant, scattering amplitudes of quarks, glu- ons and bosons, nonlinear oscillator theory, experimental mathematics, evaluation of orthogonal polynomials, numerical integration of ODEs, computation of periodic orbits, studies of the splitting of separatrices, detection of strange nonchaotic at- tractors, Ising theory, quantum held theory, and discrete dynamical systems. We conclude that high-precision arithmetic facilities are now an indispensable compo- nent of a modern large-scale scientic computing environment.

  19. High precision pulsar timing and spin frequency second derivatives

    Liu, X. J.; Bassa, C. G.; Stappers, B. W.

    2018-05-01

    We investigate the impact of intrinsic, kinematic and gravitational effects on high precision pulsar timing. We present an analytical derivation and a numerical computation of the impact of these effects on the first and second derivative of the pulsar spin frequency. In addition, in the presence of white noise, we derive an expression to determine the expected measurement uncertainty of a second derivative of the spin frequency for a given timing precision, observing cadence and timing baseline and find that it strongly depends on the latter (∝t-7/2). We show that for pulsars with significant proper motion, the spin frequency second derivative is dominated by a term dependent on the radial velocity of the pulsar. Considering the data sets from three Pulsar Timing Arrays, we find that for PSR J0437-4715 a detectable spin frequency second derivative will be present if the absolute value of the radial velocity exceeds 33 km s-1. Similarly, at the current timing precision and cadence, continued timing observations of PSR J1909-3744 for about another eleven years, will allow the measurement of its frequency second derivative and determine the radial velocity with an accuracy better than 14 km s-1. With the ever increasing timing precision and observing baselines, the impact of the, largely unknown, radial velocities of pulsars on high precision pulsar timing can not be neglected.

  20. High-Precision Computation: Mathematical Physics and Dynamics

    Bailey, D. H.; Barrio, R.; Borwein, J. M.

    2010-04-01

    At the present time, IEEE 64-bit oating-point arithmetic is suficiently accurate for most scientic applications. However, for a rapidly growing body of important scientic computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion e ort. This pa- per presents a survey of recent applications of these techniques and provides someanalysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, studies of the one structure constant, scattering amplitudes of quarks, glu- ons and bosons, nonlinear oscillator theory, experimental mathematics, evaluation of orthogonal polynomials, numerical integration of ODEs, computation of periodic orbits, studies of the splitting of separatrices, detection of strange nonchaotic at- tractors, Ising theory, quantum held theory, and discrete dynamical systems. We conclude that high-precision arithmetic facilities are now an indispensable compo- nent of a modern large-scale scientic computing environment.

  1. The mass of the black hole in 1A 0620-00, revisiting the ellipsoidal light curve modelling

    van Grunsven, Theo F. J.; Jonker, Peter G.; Verbunt, Frank W. M.; Robinson, Edward L.

    2017-12-01

    The mass distribution of stellar-mass black holes can provide important clues to supernova modelling, but observationally it is still ill constrained. Therefore, it is of importance to make black hole mass measurements as accurate as possible. The X-ray transient 1A 0620-00 is well studied, with a published black hole mass of 6.61 ± 0.25 M⊙, based on an orbital inclination i of 51.0° ± 0.9°. This was obtained by Cantrell et al. (2010) as an average of independent fits to V-, I- and H-band light curves. In this work, we perform an independent check on the value of i by re-analysing existing YALO/SMARTS V-, I- and H-band photometry, using different modelling software and fitting strategy. Performing a fit to the three light curves simultaneously, we obtain a value for i of 54.1° ± 1.1°, resulting in a black hole mass of 5.86 ± 0.24 M⊙. Applying the same model to the light curves individually, we obtain 58.2° ± 1.9°, 53.6° ± 1.6° and 50.5° ± 2.2° for V-, I- and H-band, respectively, where the differences in best-fitting i are caused by the contribution of the residual accretion disc light in the three different bands. We conclude that the mass determination of this black hole may still be subject to systematic effects exceeding the statistical uncertainty. Obtaining more accurate masses would be greatly helped by continuous phase-resolved spectroscopic observations simultaneous with photometry.

  2. On the number of light rings in curved spacetimes of ultra-compact objects

    Hod, Shahar

    2018-01-01

    In a very interesting paper, Cunha, Berti, and Herdeiro have recently claimed that ultra-compact objects, self-gravitating horizonless solutions of the Einstein field equations which have a light ring, must possess at least two (and, in general, an even number of) light rings, of which the inner one is stable. In the present compact paper we explicitly prove that, while this intriguing theorem is generally true, there is an important exception in the presence of degenerate light rings which, in the spherically symmetric static case, are characterized by the simple dimensionless relation 8 πrγ2 (ρ +pT) = 1 [here rγ is the radius of the light ring and { ρ ,pT } are respectively the energy density and tangential pressure of the matter fields]. Ultra-compact objects which belong to this unique family can have an odd number of light rings. As a concrete example, we show that spherically symmetric constant density stars with dimensionless compactness M / R = 1 / 3 possess only one light ring which, interestingly, is shown to be unstable.

  3. Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD - Progress on high precision AMS measurements

    Guettler, D., E-mail: guettler@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland); Wacker, L. [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland); Kromer, B.; Friedrich, M. [Heidelberg Academy of Sciences, 69120 Heidelberg (Germany); Institute of Botany, University of Hohenheim, 70593 Stuttgart (Germany); Synal, H.-A. [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland)

    2013-01-15

    Oak tree rings from Southern Germany covering the AD 1010-1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the {sup 14}C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25-40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

  4. Circadian phase response curves to light in older and young women and men

    Rex Katharine M

    2007-07-01

    Full Text Available Abstract Background The phase of a circadian rhythm reflects where the peak and the trough occur, for example, the peak and trough of performance within the 24 h. Light exposure can shift this phase. More extensive knowledge of the human circadian phase response to light is needed to guide light treatment for shiftworkers, air travelers, and people with circadian rhythm phase disorders. This study tested the hypotheses that older adults have absent or weaker phase-shift responses to light (3000 lux, and that women's responses might differ from those of men. Methods After preliminary health screening and home actigraphic recording baselines, 50 young adults (ages 18–31 years and 56 older adults (ages 59–75 years remained in light-controlled laboratory surroundings for 4.7 to 5.6 days, while experiencing a 90-min ultra-short sleep-wake cycle. Following at least 30 h in-lab baseline, over the next 51 h, participants were given 3 treatments with 3000 lux white light, each treatment for 3 h, centered at one of 8 clock times. The circadian rhythms of urinary aMT6s (a melatonin metabolite, free cortisol, oral temperature, and wrist activity were assessed at baseline and after treatment. Results Light (3000 lux for 3 h on 3 days induced maximal phase shifts of about 3 h. Phase shifts did not differ significantly in amplitude among older and young groups or among women and men. At home and at baseline, compared to the young, the older adults were significantly phase-advanced in sleep, cortisol, and aMT6s onset, but not advanced in aMT6s acrophase or the temperature rhythm. The inflection from delays to advances was approximately 1.8 h earlier among older compared to young participants in reference to their aMT6s rhythm peaks, and it was earlier in clock time. Conclusion In these experimental conditions, 3000 lux light could shift the phase of circadian rhythms to about the same extent among older and young adults, but the optimal light timing for

  5. One-phase and two-phase homologous curves for coolant pumps of the pressurized light water nuclear reactors

    Santos, G.A. dos.

    1990-01-01

    The two-phase coolant pump model of pressurized light water nuclear reactors is an important point for the loss of primary coolant accident analysis. The single-phase pump characteristics are an essential feature for operational transients studies, for example, the shut-down and start-up of pump. These parameters, in terms of the homologous curves, set up the complete performance of the pump and are input for transients and accidents analysis thermal-hydraulic codes. This work propose a mathematical model able to predict the single-phase and two-phase homologous curves where it was incorporated geometric and operational pump condition. The results were compared with the experimental tests data from literature and it has showed a good agreement. (author)

  6. CONSTRUCTION OF AN EARTH MODEL: ANALYSIS OF EXOPLANET LIGHT CURVES AND MAPPING THE NEXT EARTH WITH THE NEW WORLDS OBSERVER

    Oakley, P. H. H.; Cash, W.

    2009-01-01

    The orbital light curve of a terrestrial exoplanet will likely contain valuable information about the surface and atmospheric features of the planet, both in its overall shape and hourly variations. We have constructed an empirically based code capable of simulating observations of the Earth from any orientation, at any time of year with continuously updated cloud and snow coverage with a New Worlds Observatory. By simulating these observations over a full orbital revolution at a distance of 10 pc we determine that the detection of an obliquity or seasonal terrain change is possible at low inclinations. In agreement with other studies, a 4 m New Worlds Observer can accurately determine the rotation rate of the planet at a success rate from ∼30% to 80% with only 5 days of observations depending on the signal to noise of the observations. We also attempt simple inversions of these diurnal light curves to sketch a map of the reflecting planet's surface features. This mapping technique is only successful with highly favorable systems and in particular requires that the cloud coverage must be lower than the Earth's average. Our test case of a 2 M + planet at 7 pc distance with low exo-zodiacal light and 25% cloud coverage produced crude, but successful results. Additionally, with these highly favorable systems NWO may be able to discern the presence of liquid surface water (or other smooth surfaces) though it requires a complex detection available only at crescent phases in high inclination systems.

  7. High precision 3D coordinates location technology for pellet

    Fan Yong; Zhang Jiacheng; Zhou Jingbin; Tang Jun; Xiao Decheng; Wang Chuanke; Dong Jianjun

    2010-01-01

    In inertial confinement fusion (ICF) system, manual way has been used to collimate the pellet traditionally, which is time-consuming and low-level automated. A new method based on Binocular Vision is proposed, which can place the prospecting apparatus on the public diagnosis platform to reach relevant engineering target and uses the high precision two dimension calibration board. Iterative method is adopted to satisfy 0.1 pixel for corner extraction precision. Furthermore, SVD decomposition is used to remove the singularity corners and advanced Zhang's calibration method is applied to promote camera calibration precision. Experiments indicate that the RMS of three dimension coordinate measurement precision is 25 μm, and the max system RMS of distance measurement is better than 100 μm, satisfying the system index requirement. (authors)

  8. High precision measurements of 26Naβ- decay

    Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hardy, J. C.; Hyland, B.; Iacob, V. E.; Koopmans, K. A.; Kulp, W. D.; Leslie, J. R.; MacDonald, J. A.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Wood, J. L.; Zganjar, E. F.

    2005-04-01

    High-precision measurements of the half-life and β-branching ratios for the β- decay of 26Na to 26Mg have been measured in β-counting and γ-decay experiments, respectively. A 4π proportional counter and fast tape transport system were employed for the half-life measurement, whereas the γ rays emitted by the daughter nucleus 26Mg were detected with the 8π γ-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of 26Na was determined to be T1/2=1.07128±0.00013±0.00021s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

  9. The SFD - 80 M high precision double axis facing lathe

    Bran, T.; Dragomir, I.; Rusu, I.; Stanciu, S.; Niculceanu, F.; Nica, O.; Popescu, M.; Bailescu, V.; Burcea, Gh.; Turcanu, V.

    2001-01-01

    A high precision double axis facing lathe was designed for machining the 'final end-cup' by exterior conical lathing. The lathe is semi-automatic and includes two independent identical units. The general constructive, dimensional and functional characteristics are presented as well as the specific power consumptions. As compared to other machines able to perform the same operations this machine presents the following novel aspects: - it is dedicated from the design stage to the workpiece to be machined; - the splinting speed is quasi-constant all along the processing span (irrespective of the cutting diameter at which the tool is fixed, in its trajectory generating the exterior cone). At 100% and 80% nominal power values the yield is 240 workpiece/hour and 192 workpiece/hour, respectively

  10. High Precision Renormalization Group Study of the Roughening Transition

    Hasenbusch, M; Pinn, K

    1994-01-01

    We confirm the Kosterlitz-Thouless scenario of the roughening transition for three different Solid-On-Solid models: the Discrete Gaussian model, the Absolute-Value-Solid-On-Solid model and the dual transform of the XY model with standard (cosine) action. The method is based on a matching of the renormalization group flow of the candidate models with the flow of a bona fide KT model, the exactly solvable BCSOS model. The Monte Carlo simulations are performed using efficient cluster algorithms. We obtain high precision estimates for the critical couplings and other non-universal quantities. For the XY model with cosine action our critical coupling estimate is $\\beta_R^{XY}=1.1197(5)$. For the roughening coupling of the Discrete Gaussian and the Absolute-Value-Solid-On-Solid model we find $K_R^{DG}=0.6645(6)$ and $K_R^{ASOS}=0.8061(3)$, respectively.

  11. Application of high precision temperature control technology in infrared testing

    Cao, Haiyuan; Cheng, Yong; Zhu, Mengzhen; Chu, Hua; Li, Wei

    2017-11-01

    In allusion to the demand of infrared system test, the principle of Infrared target simulator and the function of the temperature control are presented. The key technology of High precision temperature control is discussed, which include temperature gathering, PID control and power drive. The design scheme of temperature gathering is put forward. In order to reduce the measure error, discontinuously current and four-wire connection for the platinum thermal resistance are adopted. A 24-bits AD chip is used to improve the acquisition precision. Fuzzy PID controller is designed because of the large time constant and continuous disturbance of the environment temperature, which result in little overshoot, rapid response, high steady-state accuracy. Double power operational amplifiers are used to drive the TEC. Experiments show that the key performances such as temperature control precision and response speed meet the requirements.

  12. Optimal dynamic performance for high-precision actuators/stages

    Preissner, C.; Lee, S.-H.; Royston, T. J.; Shu, D.

    2002-01-01

    System dynamic performance of actuator/stage groups, such as those found in optical instrument positioning systems and other high-precision applications, is dependent upon both individual component behavior and the system configuration. Experimental modal analysis techniques were implemented to determine the six degree of freedom stiffnesses and damping for individual actuator components. These experimental data were then used in a multibody dynamic computer model to investigate the effect of stage group configuration. Running the computer model through the possible stage configurations and observing the predicted vibratory response determined the optimal stage group configuration. Configuration optimization can be performed for any group of stages, provided there is stiffness and damping data available for the constituent pieces

  13. High Precision Infrared Temperature Measurement System Based on Distance Compensation

    Chen Jing

    2017-01-01

    Full Text Available To meet the need of real-time remote monitoring of human body surface temperature for optical rehabilitation therapy, a non-contact high-precision real-time temperature measurement method based on distance compensation was proposed, and the system design was carried out. The microcontroller controls the infrared temperature measurement module and the laser range module to collect temperature and distance data. The compensation formula of temperature with distance wass fitted according to the least square method. Testing had been performed on different individuals to verify the accuracy of the system. The results indicate that the designed non-contact infrared temperature measurement system has a residual error of less than 0.2°C and the response time isless than 0.1s in the range of 0 to 60cm. This provides a reference for developing long-distance temperature measurement equipment in optical rehabilitation therapy.

  14. High-precision thermal and electrical characterization of thermoelectric modules

    Kolodner, Paul

    2014-05-01

    This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 °C and 80 °C and is normally used for measurements of heat currents in the range 0-10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 °C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.

  15. The various correction methods to the high precision aeromagnetic data

    Xu Guocang; Zhu Lin; Ning Yuanli; Meng Xiangbao; Zhang Hongjian

    2014-01-01

    In the airborne geophysical survey, an outstanding achievement first depends on the measurement precision of the instrument, and the choice of measurement conditions, the reliability of data collection, followed by the correct method of measurement data processing, the rationality of the data interpretation. Obviously, geophysical data processing is an important task for the comprehensive interpretation of the measurement results, processing method is correct or not directly related to the quality of the final results. we have developed a set of personal computer software to aeromagnetic and radiometric survey data processing in the process of actual production and scientific research in recent years, and successfully applied to the production. The processing methods and flowcharts to the high precision aromagnetic data were simply introduced in this paper. However, the mathematical techniques of the various correction programes to IGRF and flying height and magnetic diurnal variation were stressily discussed in the paper. Their processing effectness were illustrated by taking an example as well. (authors)

  16. High-precision reflectivity measurements: improvements in the calibration procedure

    Jupe, Marco; Grossmann, Florian; Starke, Kai; Ristau, Detlev

    2003-05-01

    The development of high quality optical components is heavily depending on precise characterization procedures. The reflectance and transmittance of laser components are the most important parameters for advanced laser applications. In the industrial fabrication of optical coatings, quality management is generally insured by spectral photometric methods according to ISO/DIS 15386 on a medium level of accuracy. Especially for high reflecting mirrors, a severe discrepancy in the determination of the absolute reflectivity can be found for spectral photometric procedures. In the first part of the CHOCLAB project, a method for measuring reflectance and transmittance with an enhanced precision was developed, which is described in ISO/WD 13697. In the second part of the CHOCLAB project, the evaluation and optimization for the presented method is scheduled. Within this framework international Round-Robin experiment is currently in progress. During this Round-Robin experiment, distinct deviations could be observed between the results of high precision measurement facilities of different partners. Based on the extended experiments, the inhomogeneity of the sample reflectivity was identified as one important origin for the deviation. Consequently, this inhomogeneity is also influencing the calibration procedure. Therefore, a method was developed that allows the calibration of the chopper blade using always the same position on the reference mirror. During the investigations, the homogeneity of several samples was characterized by a surface mapping procedure for 1064 nm. The measurement facility was extended to the additional wavelength 532 nm and a similar set-up was assembled at 10.6 μm. The high precision reflectivity procedure at the mentioned wavelengths is demonstrated for exemplary measurements.

  17. Effect of F- and Z2-light illumination on thermal glow curves of pretreated NaCl:Ca phosphors

    Joshi, R.V.; Dhake, K.P.; Joshi, T.R.

    1985-01-01

    It is known that colour centres are produced when doped or undoped alkali halides are exposed to ionizing radiation. Earlier work has also revealed an intimate relationship between the thermoluminescence (TL) centres associated with the glow peaks and different species of colour centres. The aim of the present investigation has been to find out the species of colour centres associated with the observed thermal glow peaks. The measurements were carried out on thermally treated Ca-doped NaCl phosphors. The thermal treatment involves annealing of the phosphors at 550 C. The specimens were irradiated by a 90 Sr 20 mCi source. A figure showing the glow curves recorded immediately after β-irradiation, after β-irradiation followed by F-light illumination and after β-irradiation followed by 20 min decay at room temperature. The F-light illumination leads to the quenching of the peak at 137 C and generates new peaks at 113 and 157 C. The bleaching effect becomes more significant with the increase in the duration of F-light illumination. The effect of F-light illumination followed by Z 2 -light illumination shows that of the two peaks appearing earlier, the 113 C peak is selectively suppressed. The isothermal bleaching at room temperature for 20 min does not affect the intensity of the 137 C peak. The results are discussed. (author)

  18. CSI 2264: CHARACTERIZING YOUNG STARS IN NGC 2264 WITH SHORT-DURATION PERIODIC FLUX DIPS IN THEIR LIGHT CURVES

    Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); McGinnis, Pauline; Alencar, Silvia H. P. [Departamento de Física—ICEx—UFMG, Av. Antônio Carlos, 6627, 30270-901, Belo Horizonte, MG (Brazil); Hillenbrand, Lynne A.; Carpenter, John [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Turner, Neal J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Terebey, Susan [Department of Physics and Astronomy, 5151 State University Drive, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Morales-Calderón, María [Centro de Astrobiología, Dpto. de Astrofísica, INTA-CSIC, PO BOX 78, E-28691, ESAC Campus, Villanueva de la Cañada, Madrid (Spain); Bouvier, Jerome; Venuti, Laura [Université de Grenoble, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), F-38000 Grenoble (France); CNRS, IPAG, F-38000 Grenoble (France); Hartmann, Lee; Calvet, Nuria [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); Micela, Giusi; Flaccomio, Ettore [INAF—Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134, Palermo (Italy); Song, Inseok [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602–2451 (United States); Gutermuth, Rob, E-mail: stauffer@ipac.caltech.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); and others

    2015-04-15

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall.

  19. CSI 2264: CHARACTERIZING YOUNG STARS IN NGC 2264 WITH SHORT-DURATION PERIODIC FLUX DIPS IN THEIR LIGHT CURVES

    Stauffer, John; Cody, Ann Marie; Rebull, Luisa; Plavchan, Peter; Carey, Sean; McGinnis, Pauline; Alencar, Silvia H. P.; Hillenbrand, Lynne A.; Carpenter, John; Turner, Neal J.; Terebey, Susan; Morales-Calderón, María; Bouvier, Jerome; Venuti, Laura; Hartmann, Lee; Calvet, Nuria; Micela, Giusi; Flaccomio, Ettore; Song, Inseok; Gutermuth, Rob

    2015-01-01

    We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent with their having inner disk walls near the Keplerian co-rotation radius. The repeating photometric dips have FWHMs generally less than 1 day, depths almost always less than 15%, and periods (3 < P < 11 days) consistent with dust near the Keplerian co-rotation period. The flux dips vary considerably in their depth from epoch to epoch, but usually persist for several weeks and, in two cases, were present in data collected in successive years. For several of these stars, we also measure the photospheric rotation period and find that the rotation and dip periods are the same, as predicted by standard “disk-locking” models. We attribute these flux dips to clumps of material in or near the inner disk wall, passing through our line of sight to the stellar photosphere. In some cases, these dips are also present in simultaneous Spitzer IRAC light curves at 3.6 and 4.5 microns. We characterize the properties of these dips, and compare the stars with light curves exhibiting this behavior to other classes of YSOs in NGC 2264. A number of physical mechanisms could locally increase the dust scale height near the inner disk wall, and we discuss several of those mechanisms; the most plausible mechanisms are either a disk warp due to interaction with the stellar magnetic field or dust entrained in funnel-flow accretion columns arising near the inner disk wall

  20. SDSS J14584479+3720215: A BENCHMARK JHK{sub S} BLAZAR LIGHT CURVE FROM THE 2MASS CALIBRATION SCANS

    Davenport, James R. A.; Ruan, John J.; Becker, Andrew C. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Macleod, Chelsea L. [Physics Department, The United States Naval Academy, 572c Holloway Road, Annapolis, MD 21402 (United States); Cutri, Roc M., E-mail: jrad@astro.washington.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-04-10

    Active galactic nuclei (AGNs) are well-known to exhibit flux variability across a wide range of wavelength regimes, but the precise origin of the variability at different wavelengths remains unclear. To investigate the relatively unexplored near-IR (NIR) variability of the most luminous AGNs, we conduct a search for variability using well sampled JHK{sub s}-band light curves from the Two Micron All Sky Survey (2MASS) calibration fields. Our sample includes 27 known quasars with an average of 924 epochs of observation over three years, as well as one spectroscopically confirmed blazar (SDSS J14584479+3720215) with 1972 epochs of data. This is the best-sampled NIR photometric blazar light curve to date, and it exhibits correlated, stochastic variability that we characterize with continuous auto-regressive moving average (CARMA) models. None of the other 26 known quasars had detectable variability in the 2MASS bands above the photometric uncertainty. A blind search of the 2MASS calibration field light curves for active galactic nucleus (AGN) candidates based on fitting CARMA(1,0) models (damped-random walk) uncovered only seven candidates. All seven were young stellar objects within the ρ Ophiuchus star forming region, five with previous X-ray detections. A significant γ-ray detection (5σ) for the known blazar using 4.5 yr of Fermi photon data is also found. We suggest that strong NIR variability of blazars, such as seen for SDSS J14584479+3720215, can be used as an efficient method of identifying previously unidentified γ-ray blazars, with low contamination from other AGNs.

  1. Modelling the KIC8462852 light curves: compatibility of the dips and secular dimming with an exocomet interpretation

    Wyatt, M. C.; van Lieshout, R.; Kennedy, G. M.; Boyajian, T. S.

    2018-02-01

    This paper shows how the dips and secular dimming in the KIC8462852 light curve can originate in circumstellar material distributed around a single elliptical orbit (e.g. exocomets). The expected thermal emission and wavelength dependent dimming is derived for different orbital parameters and geometries, including dust that is optically thick to stellar radiation, and for a size distribution of dust with realistic optical properties. We first consider dust distributed evenly around the orbit, then show how to derive its uneven distribution from the optical light curve and to predict light curves at different wavelengths. The fractional luminosity of an even distribution is approximately the level of dimming times stellar radius divided by distance from the star at transit. Non-detection of dust thermal emission for KIC8462852 thus provides a lower limit on the transit distance to complement the 0.6 au upper limit imposed by 0.4 d dips. Unless the dust distribution is optically thick, the putative 16 per cent century-long secular dimming must have disappeared before the WISE 12 μm measurement in 2010, and subsequent 4.5 μm observations require transits at >0.05 au. However, self-absorption of thermal emission removes these constraints for opaque dust distributions. The passage of dust clumps through pericentre is predicted to cause infrared brightening lasting tens of days and dimming during transit, such that total flux received decreases at wavelengths dimming levels than seen for KIC8462852 are more common in the Galactic population and may be detected in future transit surveys.

  2. Structure in the early afterglow light curve of the gamma-ray burst of 29 March 2003.

    Uemura, Makoto; Kato, Taichi; Ishioka, Ryoko; Yamaoka, Hitoshi; Monard, Berto; Nogami, Daisaku; Maehara, Hiroyuki; Sugie, Atsushi; Takahashi, Susumu

    2003-06-19

    Gamma-ray bursts (GRBs) are energetic explosions that for 0.01-100 s are the brightest gamma-ray sources in the sky. Observations of the early evolution of afterglows are expected to provide clues about the nature of the bursts, but their rapid fading has hampered such studies; some recent rapid localizations of bursts have improved the situation. Here we report an early detection of the very bright afterglow of the burst of 29 March 2003 (GRB030329). Our data show that, even early in the afterglow phase, the light curve shows unexpectedly complicated structures superimposed on the fading background.

  3. Current-voltage characteristics of bulk heterojunction organic solar cells: connection between light and dark curves

    Boix, Pablo P.; Guerrero, Antonio; Garcia-Belmonte, Germa; Bisquert, Juan [Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, ES-12071 Castello (Spain); Marchesi, Luis F. [Laboratorio Interdisciplinar de, Eletroquimica e Ceramica (LIEC), Universidade Federal de Sao Carlos (Brazil); Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, ES-12071 Castello (Spain)

    2011-11-15

    A connection is established between recombination and series resistances extracted from impedance spectroscopy and current-voltage curves of polythiophene:fullerene organic solar cells. Recombination is shown to depend exclusively on the (Fermi level) voltage, which allows construction of the current-voltage characteristics in any required conditions based on a restricted set of measurements. The analysis highlights carrier recombination current as the determining mechanism of organic solar cell performance. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. High-precision relative position and attitude measurement for on-orbit maintenance of spacecraft

    Zhu, Bing; Chen, Feng; Li, Dongdong; Wang, Ying

    2018-02-01

    In order to realize long-term on-orbit running of satellites, space stations, etc spacecrafts, in addition to the long life design of devices, The life of the spacecraft can also be extended by the on-orbit servicing and maintenance. Therefore, it is necessary to keep precise and detailed maintenance of key components. In this paper, a high-precision relative position and attitude measurement method used in the maintenance of key components is given. This method mainly considers the design of the passive cooperative marker, light-emitting device and high resolution camera in the presence of spatial stray light and noise. By using a series of algorithms, such as background elimination, feature extraction, position and attitude calculation, and so on, the high precision relative pose parameters as the input to the control system between key operation parts and maintenance equipment are obtained. The simulation results show that the algorithm is accurate and effective, satisfying the requirements of the precision operation technique.

  5. Light distributions in a port wine stain model containing multiple cylindrical and curved blood vessels

    Lucassen, G. W.; Verkruysse, W.; Keijzer, M.; van Gemert, M. J.

    1996-01-01

    Knowledge of the light distribution in skin tissue is important for the understanding, prediction, and improvement of the clinical results in laser treatment of port wine stains (PWS). The objective of this study is to improve modelling of PWS treated by laser using an improved and more realistic

  6. WASP-36b: A NEW TRANSITING PLANET AROUND A METAL-POOR G-DWARF, AND AN INVESTIGATION INTO ANALYSES BASED ON A SINGLE TRANSIT LIGHT CURVE

    Smith, A. M. S.; Anderson, D. R.; Hellier, C.; Maxted, P. F. L.; Smalley, B.; Southworth, J. [Astrophysics Group, Keele University, Staffordshire, ST5 5BG (United Kingdom); Collier Cameron, A. [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS (United Kingdom); Gillon, M.; Jehin, E. [Institut d' Astrophysique et de Geophysique, Universite de Liege, Allee du 6 Aout, 17 Bat. B5C, Liege 1 (Belgium); Lendl, M.; Queloz, D.; Triaud, A. H. M. J.; Pepe, F.; Segransan, D.; Udry, S. [Observatoire de Geneve, Universite de Geneve, 51 Chemin des Maillettes, 1290 Sauverny (Switzerland); West, R. G. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Barros, S. C. C.; Pollacco, D. [Astrophysics Research Centre, School of Mathematics and Physics, Queen' s University, University Road, Belfast, BT7 1NN (United Kingdom); Street, R. A., E-mail: amss@astro.keele.ac.uk [Las Cumbres Observatory, 6740 Cortona Drive Suite 102, Goleta, CA 93117 (United States)

    2012-04-15

    We report the discovery, from WASP and CORALIE, of a transiting exoplanet in a 1.54 day orbit. The host star, WASP-36, is a magnitude V = 12.7, metal-poor G2 dwarf (T{sub eff} = 5959 {+-} 134 K), with [Fe/H] =-0.26 {+-} 0.10. We determine the planet to have mass and radius, respectively, 2.30 {+-} 0.07 and 1.28 {+-} 0.03 times that of Jupiter. We have eight partial or complete transit light curves, from four different observatories, which allow us to investigate the potential effects on the fitted system parameters of using only a single light curve. We find that the solutions obtained by analyzing each of these light curves independently are consistent with our global fit to all the data, despite the apparent presence of correlated noise in at least two of the light curves.

  7. Change of characteristic curves using light emission spectrum of the intensifying screens

    Yoon, Chul Ho; Kang, Hong Seok; Lee, In Ja; Huh, Joon

    1990-01-01

    This report is study about difference of H-D curve in regular film and ortho type film, and obtained results as follows: 1. In the blue-color emission intensifying screen, ortho type films and in the green-color emission intensifying screens, regular type are decreased in their gradient. 2. When joint use of regular type film and ortho type film, the gradient difference not seen in blue color screen. 3. The gradient difference seen clearly in G4, KM screens (green color emission intensifying). Especially, in part of high film density, the gradient difference are great. So we have to right use of screen and film because not matched used of there the sensitivity and gradient are decrease

  8. Theoretical light curve for the recurrent nova RS Ophiuchi - Determination of the white dwarf mass, composition, and distance

    Kato, M.

    1991-01-01

    Sequences of steady mass-loss solutions are constructed for the envelopes on a white dwarf with mass 1.33, 1.35, 1.36, 1.37, and 1.377 solar mass as models of the decay phase of novae. The envelopes are assumed to have a uniform chemical composition with X = 0.73, 0.6, 0.52, 0.44, 0.33, and 0.11 for hydrogen and Z = 0.02 for heavy elements by weight. An excellent agreement with the observed light curves of UV and optical is obtained in the models with a white dwarf mass of 1.36 solar mass with hydrogen content X = 0.52, and 1.37 solar mass with X = 0.6. The distance of RS Oph is obtained to be 1.6 kpc from the comparison between the theoretical and observed light curves. The success of this wind model is a strong indication from the theoretical point of view that RS Oph is a thermonuclear runaway event. 31 refs

  9. AGAPEROS Searches for microlensing in the LMC with the Pixel Method; 1, Data treatment and pixel light curves production

    Melchior, A.-L.; Ansari, R.; Aubourg, E.; Baillon, P.; Bareyre, P.; Bauer, F.; Beaulieu, J.-Ph.; Bouquet, A.; Brehin, S.; Cavalier, F.; Char, S.; Couchot, F.; Coutures, C.; Ferlet, R.; Fernandez, J.; Gaucherel, C.; Giraud-Heraud, Y.; Glicenstein, J.-F.; Goldman, B.; Gondolo, P.; Gros, M.; Guibert, J.; Gry, C.; Hardin, D.; Kaplan, J.; de Kat, J.; Lachieze-Rey, M.; Laurent, B.; Lesquoy, E.; Magneville, Ch.; Mansoux, B.; Marquette, J.-B.; Maurice, E.; Milsztajn, A.; Moniez, M.; Moreau, O.; Moscoso, L.; Palanque-Delabrouille, N.; Perdereau, O.; Prevot, L.; Renault, C.; Queinnec, F.; Rich, J.; Spiro, M.; Vigroux, L.; Zylberajch, S.; Vidal-Madjar, A.; Magneville, Ch.

    1999-01-01

    The presence and abundance of MAssive Compact Halo Objects (MACHOs) towards the Large Magellanic Cloud (LMC) can be studied with microlensing searches. The 10 events detected by the EROS and MACHO groups suggest that objects with 0.5 Mo could fill 50% of the dark halo. This preferred mass is quite surprising, and increasing the presently small statistics is a crucial issue. Additional microlensing of stars too dim to be resolved in crowded fields should be detectable using the Pixel Method. We present here an application of this method to the EROS 91-92 data (one tenth of the whole existing data set). We emphasize the data treatment required for monitoring pixel fluxes. Geometric and photometric alignments are performed on each image. Seeing correction and error estimates are discussed. 3.6" x 3.6" super-pixel light curves, thus produced, are very stable over the 120 days time-span. Fluctuations at a level of 1.8% of the flux in blue and 1.3% in red are measured on the pixel light curves. This level of stabil...

  10. High Precision Sunphotometer using Wide Dynamic Range (WDR) Camera Tracking

    Liss, J.; Dunagan, S. E.; Johnson, R. R.; Chang, C. S.; LeBlanc, S. E.; Shinozuka, Y.; Redemann, J.; Flynn, C. J.; Segal-Rosenhaimer, M.; Pistone, K.; Kacenelenbogen, M. S.; Fahey, L.

    2016-12-01

    High Precision Sunphotometer using Wide Dynamic Range (WDR) Camera TrackingThe NASA Ames Sun-photometer-Satellite Group, DOE, PNNL Atmospheric Sciences and Global Change Division, and NASA Goddard's AERONET (AErosol RObotic NETwork) team recently collaborated on the development of a new airborne sunphotometry instrument that provides information on gases and aerosols extending far beyond what can be derived from discrete-channel direct-beam measurements, while preserving or enhancing many of the desirable AATS features (e.g., compactness, versatility, automation, reliability). The enhanced instrument combines the sun-tracking ability of the current 14-Channel NASA Ames AATS-14 with the sky-scanning ability of the ground-based AERONET Sun/sky photometers, while extending both AATS-14 and AERONET capabilities by providing full spectral information from the UV (350 nm) to the SWIR (1,700 nm). Strengths of this measurement approach include many more wavelengths (isolated from gas absorption features) that may be used to characterize aerosols and detailed (oversampled) measurements of the absorption features of specific gas constituents. The Sky Scanning Sun Tracking Airborne Radiometer (3STAR) replicates the radiometer functionality of the AATS-14 instrument but incorporates modern COTS technologies for all instruments subsystems. A 19-channel radiometer bundle design is borrowed from a commercial water column radiance instrument manufactured by Biospherical Instruments of San Diego California (ref, Morrow and Hooker)) and developed using NASA funds under the Small Business Innovative Research (SBIR) program. The 3STAR design also incorporates the latest in robotic motor technology embodied in Rotary actuators from Oriental motor Corp. having better than 15 arc seconds of positioning accuracy. Control system was designed, tested and simulated using a Hybrid-Dynamical modeling methodology. The design also replaces the classic quadrant detector tracking sensor with a

  11. CSI 2264: simultaneous optical and infrared light curves of young disk-bearing stars in NGC 2264 with CoRoT and Spitzer—evidence for multiple origins of variability

    Cody, Ann Marie; Stauffer, John; Rebull, Luisa M.; Carey, Sean; Baglin, Annie; Micela, Giuseppina; Flaccomio, Ettore; Morales-Calderón, María; Aigrain, Suzanne; Bouvier, Jèrôme; Hillenbrand, Lynne A.; Carpenter, John; Findeisen, Krzysztof; Gutermuth, Robert; Song, Inseok; Turner, Neal; Alencar, Silvia H. P.; Zwintz, Konstanze; Plavchan, Peter; Terebey, Susan

    2014-01-01

    We present the Coordinated Synoptic Investigation of NGC 2264, a continuous 30 day multi-wavelength photometric monitoring campaign on more than 1000 young cluster members using 16 telescopes. The unprecedented combination of multi-wavelength, high-precision, high-cadence, and long-duration data opens a new window into the time domain behavior of young stellar objects. Here we provide an overview of the observations, focusing on results from Spitzer and CoRoT. The highlight of this work is detailed analysis of 162 classical T Tauri stars for which we can probe optical and mid-infrared flux variations to 1% amplitudes and sub-hour timescales. We present a morphological variability census and then use metrics of periodicity, stochasticity, and symmetry to statistically separate the light curves into seven distinct classes, which we suggest represent different physical processes and geometric effects. We provide distributions of the characteristic timescales and amplitudes and assess the fractional representation within each class. The largest category (>20%) are optical 'dippers' with discrete fading events lasting ∼1-5 days. The degree of correlation between the optical and infrared light curves is positive but weak; notably, the independently assigned optical and infrared morphology classes tend to be different for the same object. Assessment of flux variation behavior with respect to (circum)stellar properties reveals correlations of variability parameters with Hα emission and with effective temperature. Overall, our results point to multiple origins of young star variability, including circumstellar obscuration events, hot spots on the star and/or disk, accretion bursts, and rapid structural changes in the inner disk.

  12. A Data-driven Study of RR Lyrae Near-IR Light Curves: Principal Component Analysis, Robust Fits, and Metallicity Estimates

    Hajdu, Gergely; Dékány, István; Catelan, Márcio; Grebel, Eva K.; Jurcsik, Johanna

    2018-04-01

    RR Lyrae variables are widely used tracers of Galactic halo structure and kinematics, but they can also serve to constrain the distribution of the old stellar population in the Galactic bulge. With the aim of improving their near-infrared photometric characterization, we investigate their near-infrared light curves, as well as the empirical relationships between their light curve and metallicities using machine learning methods. We introduce a new, robust method for the estimation of the light-curve shapes, hence the average magnitudes of RR Lyrae variables in the K S band, by utilizing the first few principal components (PCs) as basis vectors, obtained from the PC analysis of a training set of light curves. Furthermore, we use the amplitudes of these PCs to predict the light-curve shape of each star in the J-band, allowing us to precisely determine their average magnitudes (hence colors), even in cases where only one J measurement is available. Finally, we demonstrate that the K S-band light-curve parameters of RR Lyrae variables, together with the period, allow the estimation of the metallicity of individual stars with an accuracy of ∼0.2–0.25 dex, providing valuable chemical information about old stellar populations bearing RR Lyrae variables. The methods presented here can be straightforwardly adopted for other classes of variable stars, bands, or for the estimation of other physical quantities.

  13. A high precision semi-analytic mass function

    Del Popolo, Antonino [Dipartimento di Fisica e Astronomia, University of Catania, Viale Andrea Doria 6, I-95125 Catania (Italy); Pace, Francesco [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL (United Kingdom); Le Delliou, Morgan, E-mail: adelpopolo@oact.inaf.it, E-mail: francesco.pace@manchester.ac.uk, E-mail: delliou@ift.unesp.br [Instituto de Física Teorica, Universidade Estadual de São Paulo (IFT-UNESP), Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2—Barra Funda, 01140-070 São Paulo, SP Brazil (Brazil)

    2017-03-01

    In this paper, extending past works of Del Popolo, we show how a high precision mass function (MF) can be obtained using the excursion set approach and an improved barrier taking implicitly into account a non-zero cosmological constant, the angular momentum acquired by tidal interaction of proto-structures and dynamical friction. In the case of the ΛCDM paradigm, we find that our MF is in agreement at the 3% level to Klypin's Bolshoi simulation, in the mass range M {sub vir} = 5 × 10{sup 9} h {sup −1} M {sub ⊙}–−5 × 10{sup 14} h {sup −1} M {sub ⊙} and redshift range 0 ∼< z ∼< 10. For z = 0 we also compared our MF to several fitting formulae, and found in particular agreement with Bhattacharya's within 3% in the mass range 10{sup 12}–10{sup 16} h {sup −1} M {sub ⊙}. Moreover, we discuss our MF validity for different cosmologies.

  14. A high-precision synchronization circuit for clock distribution

    Lu Chong; Tan Hongzhou; Duan Zhikui; Ding Yi

    2015-01-01

    In this paper, a novel structure of a high-precision synchronization circuit, HPSC, using interleaved delay units and a dynamic compensation circuit is proposed. HPSCs are designed for synchronization of clock distribution networks in large-scale integrated circuits, where high-quality clocks are required. The application of a hybrid structure of a coarse delay line and dynamic compensation circuit performs roughly the alignment of the clock signal in two clock cycles, and finishes the fine tuning in the next three clock cycles with the phase error suppressed under 3.8 ps. The proposed circuit is implemented and fabricated using a SMIC 0.13 μm 1P6M process with a supply voltage at 1.2 V. The allowed operation frequency ranges from 200 to 800 MHz, and the duty cycle ranges between [20%, 80%]. The active area of the core circuits is 245 × 134 μm 2 , and the power consumption is 1.64 mW at 500 MHz. (paper)

  15. Electromagnetic Charge Radius of the Pion at High Precision

    Ananthanarayan, B.; Caprini, Irinel; Das, Diganta

    2017-09-01

    We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of the poorly known modulus of the form factor, we use its phase, known with high accuracy from Roy equations for π π elastic scattering via the Fermi-Watson theorem. We use also the values of the modulus at several higher timelike energies, where the data from e+e- annihilation and τ decay are mutually consistent, as well as the most recent measurements at spacelike momenta. The experimental uncertainties are implemented by Monte Carlo simulations. The results, which do not rely on a specific parametrization, are optimal for the given input information and do not depend on the unknown phase of the form factor above the first inelastic threshold. Our prediction for the charge radius of the pion is rπ=(0.657 ±0.003 ) fm , which amounts to an increase in precision by a factor of about 2.7 compared to the Particle Data Group average.

  16. High precision relocation of earthquakes at Iliamna Volcano, Alaska

    Statz-Boyer, P.; Thurber, C.; Pesicek, J.; Prejean, S.

    2009-01-01

    In August 1996, a period of elevated seismicity commenced beneath Iliamna Volcano, Alaska. This activity lasted until early 1997, consisted of over 3000 earthquakes, and was accompanied by elevated emissions of volcanic gases. No eruption occurred and seismicity returned to background levels where it has remained since. We use waveform alignment with bispectrum-verified cross-correlation and double-difference methods to relocate over 2000 earthquakes from 1996 to 2005 with high precision (~ 100??m). The results of this analysis greatly clarify the distribution of seismic activity, revealing distinct features previously hidden by location scatter. A set of linear earthquake clusters diverges upward and southward from the main group of earthquakes. The events in these linear clusters show a clear southward migration with time. We suggest that these earthquakes represent either a response to degassing of the magma body, circulation of fluids due to exsolution from magma or heating of ground water, or possibly the intrusion of new dikes beneath Iliamna's southern flank. In addition, we speculate that the deeper, somewhat diffuse cluster of seismicity near and south of Iliamna's summit indicates the presence of an underlying magma body between about 2 and 4??km depth below sea level, based on similar features found previously at several other Alaskan volcanoes. ?? 2009 Elsevier B.V.

  17. High-Precision Direct Mass Determination of Unstable Isotopes

    2002-01-01

    The extension of systematic high-precision measurements of the nuclear mass to nuclei far from the valley of $\\beta$ stability is of great interest in nuclear physics and astrophysics. The mass, or binding energy, is a fundamental gross property and a key input parameter for nuclear matter calculations. It is also a sensitive probe for collective and single-particle effects in nuclear structure. \\\\ \\\\ For such purposes, nuclear masses need to be known to an accuracy of about 10$^{-7}$ (i.e. $\\Delta$M~$\\leq$~10~keV for A~=~100). To resolve a particular mass from its nuclear isomers and isobars, resolving power of 10$^6$ are often required. To achieve this, the ions delivered by the on-line mass separator ISOLDE are confined in a Penning quadrupole trap. This trap is placed in the very homogeneous and stable magnetic field of a superconducting magnet. Here, the cyclotron frequency and hence the mass are determined. \\\\ \\\\ The first measurements using this new technique have been completed for a long chain of Cs ...

  18. High precision target center determination from a point cloud

    K. Kregar

    2013-10-01

    Full Text Available Many applications of terrestrial laser scanners (TLS require the determination of a specific point from a point cloud. In this paper procedure of high precision planar target center acquisition from point cloud is presented. The process is based on an image matching algorithm but before we can deal with raster image to fit a target on it, we need to properly determine the best fitting plane and project points on it. The main emphasis of this paper is in the precision estimation and propagation through the whole procedure which allows us to obtain precision assessment of final results (target center coordinates. Theoretic precision estimations – obtained through the procedure were rather high so we compared them with the empiric precision estimations obtained as standard deviations of results of 60 independently scanned targets. An χ2-test confirmed that theoretic precisions are overestimated. The problem most probably lies in the overestimated precisions of the plane parameters due to vast redundancy of points. However, empirical precisions also confirmed that the proposed procedure can ensure a submillimeter precision level. The algorithm can automatically detect grossly erroneous results to some extent. It can operate when the incidence angles of a laser beam are as high as 80°, which is desirable property if one is going to use planar targets as tie points in scan registration. The proposed algorithm will also contribute to improve TLS calibration procedures.

  19. Software Development of High-Precision Ephemerides of Solar System

    Jong-Seob Shin

    1995-06-01

    Full Text Available We solved n-body problem about 9 plants, moon, and 4 minor planets with relativistic effect related to the basic equation of motion of the solar system. Perturbations including figure potential of the earth and the moon and solid earth tidal effect were considered on this relativistic equation of motion. The orientations employed precession and nutation for the earth, and lunar libration model with Eckert's lunar libration model based on J2000.0 were used for the moon. Finally, we developed heliocentric ecliptic position and velocity of each planet using this software package named the SSEG (Solar System Ephemerides Generator by long-term (more than 100 years simulation on CRAY-2S super computer, through testing each subroutine on personal computer and short-time (within 800days running on SUN3/280 workstation. Epoch of input data JD2440400.5 were adopted in order to compare our results to the data archived from JPL's DE200 by Standish and Newhall. Above equation of motion was integrated numerically having 1-day step-size interval through 40,000 days (about 110 years long as total computing interval. We obtained high-precision ephemerides of the planets with maximum error, less than ~2 x 10-8AU (≈±3km compared with DE200 data(except for mars and moon.

  20. Characterisation of work function fluctuations for high-precision experiments

    Kahlenberg, Jan; Bickmann, Edward; Heil, Werner; Otten, Ernst W.; Schmidt, Christian; Wunderle, Alexander [Johannes Gutenberg-Universitaet Mainz (Germany); Babutzka, Martin; Schoenung, Kerstin [Karlsruher Institut fuer Technologie (Germany); Beck, Marcus [Johannes Gutenberg-Universitaet Mainz (Germany); Helmholtz-Institut Mainz (Germany)

    2016-07-01

    For a wide range of high-precision experiments in physics, well-defined electric potentials for achieving high measurement accuracies are required. An accurate determination of the electric potential is crucial for the measurement of the neutrino mass (KATRIN) as well as the measurement of the e{sup -} anti ν{sub e} correlation coefficient a in free neutron decay (aSPECT). Work function fluctuations on the electrodes lead to uncertainties in the distribution of the electric potential. For aSPECT, the electric potential has to be known at an accuracy of 10 mV. However, due to the patch effect of gold, work function fluctuations of several 100 meV can occur. Therefore, the work function distributions of the gold-plated electrodes have been measured using a Kelvin probe. Furthermore, the change of work function distributions over time as well as the influence of relative humidity on the work function measurement have been investigated. For aSPECT, the work function distributions of the gold-plated electrodes have been measured using a Kelvin probe. Due to the patch effect of gold, work function fluctuations of up to 160 meV occur. This would lead to a significant uncertainty of the potential barrier, which should be known at an accuracy of 10 mV. Furthermore, the change of work function distributions over time as well as the influence of relative humidity on the work function measurement have been investigated.

  1. SKLUST device for high-precision gluing of MWPC

    Amaglobeli, N.S.; Burov, R.V.; Sakandelidze, R.M.; Sakhelashvili, T.M.; Chiladze, B.G.; Glonti, G.L.; Glonti, L.N.

    2005-01-01

    The SKLUST device has been created for gluing precision plane-parallel anode, cathode of spacer bars and integral anode and cathode frames of the MWPCs or flat surfaces of the large-area cathode planes for them in the case that thin copper clad stesalit or glass-cloth-base laminate is used as the cathode, for example, for the CSC chambers. In contrast to usual gluing, in this device the glued components are not pressed to each other. SKLUST allows making high-precision products in laboratory conditions without preliminarily machining its components and receiving a precision article practically for any area at the plane parallelism from ±0.030 up to ±0.006 mm using a non-calibrated sheet of the foiled (or unfoiled) stesalit, glass-cloth-base laminate or other flexible materials to a tolerance for the thickness ±0.2-0.5 mm or worse. On the biggest of the existing devices it is possible to fabricate an article with the maximal sizes 2400x250 mm 2 at the thickness accuracy (6±0.015) mm (maximum deviation). Whereas in the technological cycle machining of blanks to the thickness or application of exact blanks is completely excluded, the manufacturing process becomes simpler, and the price of the articles essentially reduces, especially for mass production

  2. HIGH PRECISION ROVIBRATIONAL SPECTROSCOPY OF OH{sup +}

    Markus, Charles R.; Hodges, James N.; Perry, Adam J.; Kocheril, G. Stephen; McCall, Benjamin J. [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States); Müller, Holger S. P., E-mail: bjmccall@illinois.edu [I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany)

    2016-02-01

    The molecular ion OH{sup +} has long been known to be an important component of the interstellar medium. Its relative abundance can be used to indirectly measure cosmic ray ionization rates of hydrogen, and it is the first intermediate in the interstellar formation of water. To date, only a limited number of pure rotational transitions have been observed in the laboratory making it necessary to indirectly calculate rotational levels from high-precision rovibrational spectroscopy. We have remeasured 30 transitions in the fundamental band with MHz-level precision, in order to enable the prediction of a THz spectrum of OH{sup +}. The ions were produced in a water cooled discharge of O{sub 2}, H{sub 2}, and He, and the rovibrational transitions were measured with the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These values have been included in a global fit of field free data to a {sup 3}Σ{sup −} linear molecule effective Hamiltonian to determine improved spectroscopic parameters which were used to predict the pure rotational transition frequencies.

  3. Ultracold Anions for High-Precision Antihydrogen Experiments.

    Cerchiari, G; Kellerbauer, A; Safronova, M S; Safronova, U I; Yzombard, P

    2018-03-30

    Experiments with antihydrogen (H[over ¯]) for a study of matter-antimatter symmetry and antimatter gravity require ultracold H[over ¯] to reach ultimate precision. A promising path towards antiatoms much colder than a few kelvin involves the precooling of antiprotons by laser-cooled anions. Because of the weak binding of the valence electron in anions-dominated by polarization and correlation effects-only few candidate systems with suitable transitions exist. We report on a combination of experimental and theoretical studies to fully determine the relevant binding energies, transition rates, and branching ratios of the most promising candidate La^{-}. Using combined transverse and collinear laser spectroscopy, we determined the resonant frequency of the laser cooling transition to be ν=96.592 713(91)  THz and its transition rate to be A=4.90(50)×10^{4}  s^{-1}. Using a novel high-precision theoretical treatment of La^{-} we calculated yet unmeasured energy levels, transition rates, branching ratios, and lifetimes to complement experimental information on the laser cooling cycle of La^{-}. The new data establish the suitability of La^{-} for laser cooling and show that the cooling transition is significantly stronger than suggested by a previous theoretical study.

  4. A Multi-year Search for Transits of Proxima Centauri. I. Light Curves Corresponding to Published Ephemerides

    Blank, David L.; Feliz, Dax; Collins, Karen A.; White, Graeme L.; Stassun, Keivan G.; Curtis, Ivan A.; Hart, Rhodes; Kielkopf, John F.; Nelson, Peter; Relles, Howard; Stockdale, Christopher; Jayawardene, Bandupriya; Pennypacker, Carlton R.; Shankland, Paul; Reichart, Daniel E.; Haislip, Joshua B.; Kouprianov, Vladimir V.

    2018-06-01

    Proxima Centauri has become the subject of intense study since the radial-velocity (RV) discovery by Anglada-Escudé et al. of a planet orbiting this nearby M dwarf every ∼11.2 days. If Proxima Centauri b transits its host star, independent confirmation of its existence is possible, and its mass and radius can be measured in units of the stellar host mass and radius. To date, there have been three independent claims of possible transit-like event detections in light curve observations obtained by the MOST satellite (in 2014–15), the Bright Star Survey Telescope telescope in Antarctica (in 2016), and the Las Campanas Observatory (in 2016). The claimed possible detections are tentative, due in part to the variability intrinsic to the host star, and in the case of the ground-based observations, also due to the limited duration of the light curve observations. Here, we present preliminary results from an extensive photometric monitoring campaign of Proxima Centauri, using telescopes around the globe and spanning from 2006 to 2017, comprising a total of 329 observations. Considering our data that coincide directly and/or phased with the previously published tentative transit detections, we are unable to independently verify those claims. We do, however, verify the previously reported ubiquitous and complex variability of the host star. We discuss possible interpretations of the data in light of the previous claims, and we discuss future analyses of these data that could more definitively verify or refute the presence of transits associated with the RV-discovered planet.

  5. A Miniaturized Colorimeter with a Novel Design and High Precision for Photometric Detection.

    Yan, Jun-Chao; Chen, Yan; Pang, Yu; Slavik, Jan; Zhao, Yun-Fei; Wu, Xiao-Ming; Yang, Yi; Yang, Si-Fan; Ren, Tian-Ling

    2018-03-08

    Water quality detection plays an increasingly important role in environmental protection. In this work, a novel colorimeter based on the Beer-Lambert law was designed for chemical element detection in water with high precision and miniaturized structure. As an example, the colorimeter can detect phosphorus, which was accomplished in this article to evaluate the performance. Simultaneously, a modified algorithm was applied to extend the linear measurable range. The colorimeter encompassed a near infrared laser source, a microflow cell based on microfluidic technology and a light-sensitive detector, then Micro-Electro-Mechanical System (MEMS) processing technology was used to form a stable integrated structure. Experiments were performed based on the ammonium molybdate spectrophotometric method, including the preparation of phosphorus standard solution, reducing agent, chromogenic agent and color reaction. The device can obtain a wide linear response range (0.05 mg/L up to 7.60 mg/L), a wide reliable measuring range up to 10.16 mg/L after using a novel algorithm, and a low limit of detection (0.02 mg/L). The size of flow cell in this design is 18 mm × 2.0 mm × 800 μm, obtaining a low reagent consumption of 0.004 mg ascorbic acid and 0.011 mg ammonium molybdate per determination. Achieving these advantages of miniaturized volume, high precision and low cost, the design can also be used in automated in situ detection.

  6. A Miniaturized Colorimeter with a Novel Design and High Precision for Photometric Detection

    Jun-Chao Yan

    2018-03-01

    Full Text Available Water quality detection plays an increasingly important role in environmental protection. In this work, a novel colorimeter based on the Beer-Lambert law was designed for chemical element detection in water with high precision and miniaturized structure. As an example, the colorimeter can detect phosphorus, which was accomplished in this article to evaluate the performance. Simultaneously, a modified algorithm was applied to extend the linear measurable range. The colorimeter encompassed a near infrared laser source, a microflow cell based on microfluidic technology and a light-sensitive detector, then Micro-Electro-Mechanical System (MEMS processing technology was used to form a stable integrated structure. Experiments were performed based on the ammonium molybdate spectrophotometric method, including the preparation of phosphorus standard solution, reducing agent, chromogenic agent and color reaction. The device can obtain a wide linear response range (0.05 mg/L up to 7.60 mg/L, a wide reliable measuring range up to 10.16 mg/L after using a novel algorithm, and a low limit of detection (0.02 mg/L. The size of flow cell in this design is 18 mm × 2.0 mm × 800 μm, obtaining a low reagent consumption of 0.004 mg ascorbic acid and 0.011 mg ammonium molybdate per determination. Achieving these advantages of miniaturized volume, high precision and low cost, the design can also be used in automated in situ detection.

  7. Hubble Space Telescope Ultraviolet Light Curves Reveal Interesting Properties of CC Sculptoris and RZ Leonis

    Szkody, Paula; Mukadam, Anjum S. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Toloza, Odette; Gänsicke, Boris T.; Pala, Anna F. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Dai, Zhibin [Yunnan Observatories, Chinese Academy of Sciences, 396 Yangfangwang, Guandu District, Kunming, 650216 (China); Waagen, Elizabeth O. [AAVSO, 48 Bay State Rd, Cambridge, MA 02138 (United States); Godon, Patrick; Sion, Edward M., E-mail: szkody@astro.washington.edu [Department of Astrophysics and Planetary Science, Villanova University, Villanova, PA 19085 (United States)

    2017-03-01

    Time-tag ultraviolet data obtained on the Hubble Space Telescope in 2013 reveal interesting variability related to the white dwarf spin in the two cataclysmic variables RZ Leo and CC Scl. RZ Leo shows a period at 220 s and its harmonic at 110 s, thus identifying it as a likely Intermediate Polar (IP). The spin signal is not visible in a short single night of ground-based data in 2016, but the shorter exposures in that data set indicate a possible partial eclipse. The much larger UV amplitude of the spin signal in the known IP CC Scl allows the spin of 389 s, previously only seen at outburst, to be visible at quiescence. Spectra created from the peaks and troughs of the spin times indicate a hotter temperature of several thousand degrees during the peak phases, with multiple components contributing to the UV light.

  8. High precision patterning of ITO using femtosecond laser annealing process

    Cheng, Chung-Wei; Lin, Cen-Ying

    2014-01-01

    Highlights: • We have reported a process of fabrication of crystalline indium tin oxide (c-ITO) patterns using femtosecond laser-induced crystallization with a Gaussian beam profile followed by chemical etching. • The experimental results have demonstrated that the ablation and crystallization threshold fluences of a-ITO thin film are well-defined, the line width of the c-ITO patterns is controllable. • Fast fabrication of the two parallel sub-micro (∼0.5 μm) c-ITO line patterns using a single femtosecond laser beam and a single scanning path can be achieved. • A long-length sub-micro c-ITO line pattern is fabricated, and the feasibility of fabricating c-ITO patterns is confirmed, which are expected to be used in micro-electronics devices. - Abstract: High precision patterning of crystalline indium tin oxide (c-ITO) patterns on amorphous ITO (a-ITO) thin films by femtosecond laser-induced crystallization with a Gaussian beam profile followed by chemical etching is demonstrated. In the proposed approach, the a-ITO thin film is selectively transformed into a c-ITO structure via a low heat affect zone and the well-defined thresholds (ablation and crystallization) supplied by the femtosecond laser pulse. The experimental results show that by careful control of the laser fluence above the crystallization threshold, c-ITO patterns with controllable line widths and ridge-free characteristics can be accomplished. By careful control of the laser fluence above the ablation threshold, fast fabrication of the two parallel sub-micro c-ITO line patterns using a single femtosecond laser beam and single scanning path can be achieved. Along-length sub-micro c-ITO line pattern is fabricated, and the feasibility of fabricating c-ITO patterns is confirmed, which are expected to be used in micro-electronics devices

  9. a High Precision dem Extraction Method Based on Insar Data

    Wang, Xinshuang; Liu, Lingling; Shi, Xiaoliang; Huang, Xitao; Geng, Wei

    2018-04-01

    In the 13th Five-Year Plan for Geoinformatics Business, it is proposed that the new InSAR technology should be applied to surveying and mapping production, which will become the innovation driving force of geoinformatics industry. This paper will study closely around the new outline of surveying and mapping and then achieve the TerraSAR/TanDEM data of Bin County in Shaanxi Province in X band. The studying steps are as follows; Firstly, the baseline is estimated from the orbital data; Secondly, the interferometric pairs of SAR image are accurately registered; Thirdly, the interferogram is generated; Fourth, the interferometric correlation information is estimated and the flat-earth phase is removed. In order to solve the phase noise and the discontinuity phase existing in the interferometric image of phase, a GAMMA adaptive filtering method is adopted. Aiming at the "hole" problem of missing data in low coherent area, the interpolation method of low coherent area mask is used to assist the phase unwrapping. Then, the accuracy of the interferometric baseline is estimated from the ground control points. Finally, 1 : 50000 DEM is generated, and the existing DEM data is used to verify the accuracy through statistical analysis. The research results show that the improved InSAR data processing method in this paper can obtain the high-precision DEM of the study area, exactly the same with the topography of reference DEM. The R2 can reach to 0.9648, showing a strong positive correlation.

  10. High-precision laser microcutting and laser microdrilling using diffractive beam-splitting and high-precision flexible beam alignment

    Zibner, F.; Fornaroli, C.; Holtkamp, J.; Shachaf, Lior; Kaplan, Natan; Gillner, A.

    2017-08-01

    High-precision laser micro machining gains more importance in industrial applications every month. Optical systems like the helical optics offer highest quality together with controllable and adjustable drilling geometry, thus as taper angle, aspect ratio and heat effected zone. The helical optics is based on a rotating Dove-prism which is mounted in a hollow shaft engine together with other optical elements like wedge prisms and plane plates. Although the achieved quality can be interpreted as extremely high the low process efficiency is a main reason that this manufacturing technology has only limited demand within the industrial market. The objective of the research studies presented in this paper is to dramatically increase process efficiency as well as process flexibility. During the last years, the average power of commercial ultra-short pulsed laser sources has increased significantly. The efficient utilization of the high average laser power in the field of material processing requires an effective distribution of the laser power onto the work piece. One approach to increase the efficiency is the application of beam splitting devices to enable parallel processing. Multi beam processing is used to parallelize the fabrication of periodic structures as most application only require a partial amount of the emitted ultra-short pulsed laser power. In order to achieve highest flexibility while using multi beam processing the single beams are diverted and re-guided in a way that enables the opportunity to process with each partial beam on locally apart probes or semimanufactures.

  11. Light curve solutions and out-of-eclipse variability of KIC 10031409, KIC 11228612, KIC 11403216 and KIC 11913071

    Kjurkchieva D.

    2017-01-01

    Full Text Available We carried out light curve solutions of four detached binaries observed by Kepler. As a result, their orbital inclinations, temperatures and relative stellar radii were determined. KIC 10031409 and KIC 11228612 reveal partial eclipses while the components of KIC 11403216 and KIC 11913071 undergo total eclipses. The secondary component of KIC 11403216 is probably a very late M dwarf or brown dwarf. The out-of-eclipse brightness of KIC 10031409, KIC 11228612 and KIC 11913071 vary with the orbital period and might be explained by spots on synchronously-rotating star(s. The out-of-eclipse variability of KIC 11403216 is with a period that is a third of its orbital period and may be due to spot on asynchronous rotating component. The resonance 1:3 needs future study of KIC 11403216.

  12. SN 2015as: a low-luminosity Type IIb supernova without an early light-curve peak

    Gangopadhyay, Anjasha; Misra, Kuntal; Pastorello, A.; Sahu, D. K.; Tomasella, L.; Tartaglia, L.; Singh, Mridweeka; Dastidar, Raya; Srivastav, S.; Ochner, P.; Brown, Peter J.; Anupama, G. C.; Benetti, S.; Cappellaro, E.; Kumar, Brajesh; Kumar, Brijesh; Pandey, S. B.

    2018-05-01

    We present results of the photometric (from 3 to 509 d post-explosion) and spectroscopic (up to 230 d post-explosion) monitoring campaign of the He-rich Type IIb supernova (SN) 2015as. The (B - V) colour evolution of SN 2015as closely resemble those of SN 2008ax, suggesting that SN 2015as belongs to the SN IIb subgroup that does not show the early, short-duration photometric peak. The light curve of SN 2015as reaches the B-band maximum about 22 d after the explosion, at an absolute magnitude of -16.82 ± 0.18 mag. At ˜75 d after the explosion, its spectrum transitions from that of a SN II to a SN Ib. P Cygni features due to He I lines appear at around 30 d after explosion, indicating that the progenitor of SN 2015as was partially stripped. For SN 2015as, we estimate a 56Ni mass of ˜0.08 M⊙ and ejecta mass of 1.1-2.2 M⊙, which are similar to the values inferred for SN 2008ax. The quasi-bolometric analytical light-curve modelling suggests that the progenitor of SN 2015as has a modest mass (˜0.1 M⊙), a nearly compact (˜0.05 × 1013 cm) H envelope on top of a dense, compact (˜2 × 1011 cm) and a more massive (˜1.2 M⊙) He core. The analysis of the nebular phase spectra indicates that ˜0.44 M⊙ of O is ejected in the explosion. The intensity ratio of the [Ca II]/[O I] nebular lines favours either a main-sequence progenitor mass of ˜15 M⊙ or a Wolf-Rayet star of 20 M⊙.

  13. Developing and implementing a high precision setup system

    Peng, Lee-Cheng

    The demand for high-precision radiotherapy (HPRT) was first implemented in stereotactic radiosurgery using a rigid, invasive stereotactic head frame. Fractionated stereotactic radiotherapy (SRT) with a frameless device was developed along a growing interest in sophisticated treatment with a tight margin and high-dose gradient. This dissertation establishes the complete management for HPRT in the process of frameless SRT, including image-guided localization, immobilization, and dose evaluation. The most ideal and precise positioning system can allow for ease of relocation, real-time patient movement assessment, high accuracy, and no additional dose in daily use. A new image-guided stereotactic positioning system (IGSPS), the Align RT3C 3D surface camera system (ART, VisionRT), which combines 3D surface images and uses a real-time tracking technique, was developed to ensure accurate positioning at the first place. The uncertainties of current optical tracking system, which causes patient discomfort due to additional bite plates using the dental impression technique and external markers, are found. The accuracy and feasibility of ART is validated by comparisons with the optical tracking and cone-beam computed tomography (CBCT) systems. Additionally, an effective daily quality assurance (QA) program for the linear accelerator and multiple IGSPSs is the most important factor to ensure system performance in daily use. Currently, systematic errors from the phantom variety and long measurement time caused by switching phantoms were discovered. We investigated the use of a commercially available daily QA device to improve the efficiency and thoroughness. Reasonable action level has been established by considering dosimetric relevance and clinic flow. As for intricate treatments, the effect of dose deviation caused by setup errors remains uncertain on tumor coverage and toxicity on OARs. The lack of adequate dosimetric simulations based on the true treatment coordinates from

  14. High precision efficiency calibration of a HPGe detector

    Nica, N.; Hardy, J.C.; Iacob, V.E.; Helmer, R.G.

    2003-01-01

    Many experiments involving measurements of γ rays require a very precise efficiency calibration. Since γ-ray detection and identification also requires good energy resolution, the most commonly used detectors are of the coaxial HPGe type. We have calibrated our 70% HPGe to ∼ 0.2% precision, motivated by the measurement of precise branching ratios (BR) in superallowed 0 + → 0 + β decays. These BRs are essential ingredients in extracting ft-values needed to test the Standard Model via the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, a test that it currently fails by more than two standard deviations. To achieve the required high precision in our efficiency calibration, we measured 17 radioactive sources at a source-detector distance of 15 cm. Some of these were commercial 'standard' sources but we achieved the highest relative precision with 'home-made' sources selected because they have simple decay schemes with negligible side feeding, thus providing exactly matched γ-ray intensities. These latter sources were produced by us at Texas A and M by n-activation or by nuclear reactions. Another critical source among the 17 was a 60 Co source produced by Physikalisch-Technische Bundesanstalt, Braunschweig, Germany: its absolute activity was quoted to better than 0.06%. We used it to establish our absolute efficiency, while all the other sources were used to determine relative efficiencies, extending our calibration over a large energy range (40-3500 keV). Efficiencies were also determined with Monte Carlo calculations performed with the CYLTRAN code. The physical parameters of the Ge crystal were independently determined and only two (unmeasurable) dead-layers were adjusted, within physically reasonable limits, to achieve precise absolute agreement with our measured efficiencies. The combination of measured efficiencies at more than 60 individual energies and Monte Carlo calculations to interpolate between them allows us to quote the efficiency of our

  15. A fast high-precision six-degree-of-freedom relative position sensor

    Hughes, Gary B.; Macasaet, Van P.; Griswold, Janelle; Sison, Claudia A.; Lubin, Philip; Meinhold, Peter; Suen, Jonathan; Brashears, Travis; Zhang, Qicheng; Madajian, Jonathan

    2016-03-01

    Lasers are commonly used in high-precision measurement and profiling systems. Some laser measurement systems are based on interferometry principles, and others are based on active triangulation, depending on requirements of the application. This paper describes an active triangulation laser measurement system for a specific application wherein the relative position of two fixed, rigid mechanical components is to be measured dynamically with high precision in six degrees of freedom (DOF). Potential applications include optical systems with feedback to control for mechanical vibration, such as target acquisition devices with multiple focal planes. The method uses an array of several laser emitters mounted on one component. The lasers are directed at a reflective surface on the second component. The reflective surface consists of a piecewise-planar pattern such as a pyramid, or more generally a curved reflective surface such as a hyperbolic paraboloid. The reflected spots are sensed at 2-dimensional photodiode arrays on the emitter component. Changes in the relative position of the emitter component and reflective surface will shift the location of the reflected spots within photodiode arrays. Relative motion in any degree of freedom produces independent shifts in the reflected spot locations, allowing full six-DOF relative position determination between the two component positions. Response time of the sensor is limited by the read-out rate of the photodiode arrays. Algorithms are given for position determination with limits on uncertainty and sensitivity, based on laser and spot-sensor characteristics, and assuming regular surfaces. Additional uncertainty analysis is achievable for surface irregularities based on calibration data.

  16. SEVEN NEW BINARIES DISCOVERED IN THE KEPLER LIGHT CURVES THROUGH THE BEER METHOD CONFIRMED BY RADIAL-VELOCITY OBSERVATIONS

    Faigler, S.; Mazeh, T.; Tal-Or, L.; Quinn, S. N.; Latham, D. W.

    2012-01-01

    We present seven newly discovered non-eclipsing short-period binary systems with low-mass companions, identified by the recently introduced BEER algorithm, applied to the publicly available 138-day photometric light curves obtained by the Kepler mission. The detection is based on the beaming effect (sometimes called Doppler boosting), which increases (decreases) the brightness of any light source approaching (receding from) the observer, enabling a prediction of the stellar Doppler radial-velocity (RV) modulation from its precise photometry. The BEER algorithm identifies the BEaming periodic modulation, with a combination of the well-known Ellipsoidal and Reflection/heating periodic effects, induced by short-period companions. The seven detections were confirmed by spectroscopic RV follow-up observations, indicating minimum secondary masses in the range 0.07-0.4 M ☉ . The binaries discovered establish for the first time the feasibility of the BEER algorithm as a new detection method for short-period non-eclipsing binaries, with the potential to detect in the near future non-transiting brown-dwarf secondaries, or even massive planets.

  17. High precision ages from the Torres del Paine Intrusion, Chile

    Michel, J.; Baumgartner, L.; Cosca, M.; Ovtcharova, M.; Putlitz, B.; Schaltegger, U.

    2006-12-01

    The upper crustal bimodal Torres del Paine Intrusion, southern Chile, consists of the lower Paine-Mafic- Complex and the upper Paine-Granite. Geochronologically this bimodal complex is not well studied except for a few existing data from Halpern (1973) and Sanchez (2006). The aim of this study is to supplement the existing data and to constrain the age relations between the major magmatic pulses by applying high precision U-Pb dating on accessory zircons and 40Ar/39Ar-laser-step-heating-ages on biotites from the Torres del Paine Intrusion. The magmatic rocks from mafic complex are fine to medium-grained and vary in composition from quartz- monzonites to granodiorites and gabbros. Coarse-grained olivine gabbros have intruded these rocks in the west. The granitic body is represented by a peraluminous, biotite-orthoclase-granite and a more evolved leucocratic granite in the outer parts towards the host-rock. Field observations suggest a feeder-zone for the granite in the west and that the granite postdates the mafic complex. Two granite samples of the outermost margins in the Northeast and South were analyzed. The zircons were dated by precise isotope-dilution U-Pb techniques of chemically abraded single grains. The data are concordant within the analytical error and define weighted mean 206/238U ages of 12.59 ± 0.03 Ma and 12.58 ± 0.01 Ma for the two samples respectively. A 40Ar/39Ar-age for the second sample yield a date of 12.37 ± 0.11 Ma. Three 40Ar/39Ar -ages of biotites were obtained for rocks belonging to the mafic complex. A hbl-bio- granodiorite from the central part, approximately 150 m below the subhorizontal contact with the granite, gives an age of 12.81 ± 0.11 Ma. A hbl-bio-granodiorite and an olivine-gabbro west of the feeder-zone date at 12.42 ± 0.14 Ma and 12.49 ± 0.11 Ma, respectively. The obtained older age of 12.81 Ma for the granodiorite in the central part is consistent with structural relationships of brittle fracturing of the mafic

  18. High precision and stable structures for particle detectors

    Da Mota Silva, S; Hauviller, Claude

    1999-01-01

    The central detectors used in High Energy Physics Experiments require the use of light and stable structures capable of supporting delicate and precise radiation detection elements. These structures need to be highly stable under environmental conditions where external vibrations, high radiation levels, temperature and humidity gradients should be taken into account. Their main design drivers are high dimension and dynamic stability, high stiffness to mass ratio and large radiation length. For most applications, these constraints lead us to choose Carbon Fiber Reinforced Plastics ( CFRP) as structural element. The construction of light and stable structures with CFRP for these applications can be achieved by careful design engineering and further confirmation at the prototyping phase. However, the experimental environment can influence their characteristics and behavior. In this case, theuse of adaptive structures could become a solution for this problem. We are studying structures in CFRP with bonded piezoel...

  19. SOAP-T: a tool to study the light curve and radial velocity of a system with a transiting planet and a rotating spotted star

    Oshagh, M.; Boisse, I.; Boué, G.; Montalto, M.; Santos, N. C.; Bonfils, X.; Haghighipour, N.

    2013-01-01

    We present an improved version of SOAP named "SOAP-T", which can generate the radial velocity variations and light curves for systems consisting of a rotating spotted star with a transiting planet. This tool can be used to study the anomalies inside transit light curves and the Rossiter-McLaughlin effect, to better constrain the orbital configuration and properties of planetary systems and the active zones of their host stars. Tests of the code are presented to illustrate its performance and to validate its capability when compared with analytical models and real data. Finally, we apply SOAP-T to the active star, HAT-P-11, observed by the NASA Kepler space telescope and use this system to discuss the capability of this tool in analyzing light curves for the cases where the transiting planet overlaps with the star's spots. The tool's public interface is available at http://www.astro.up.pt/resources/soap-t/

  20. Performance of the new high precision luminosity monitor of DELPHI

    Alvsvaag, S.J.; Maeland, O.A.; Klovning, A.; Benvenuti, A.C.; Giordano, V.; Guerzoni, M.; Navarria, F.L.; Perrotta, A.; Camporesi, T.; Obraztsov, V.; Paganoni, M.; Vallazza, E.; Bozzo, M.; Cereseto, R.; Barreira, G.; Espirito Santo, M.C.; Maio, A.; Onofre, A.; Peralta, L.; Pimenta, M.; Tome, B.; Carling, H.; Falk, E.; Hedberg, V.; Jarlskog, G.; Kronkvist, I.; Bonesini, M.; Chignoli, F.; Ferrari, P.; Gumenyuk, S.; Leoni, R.; Mazza, R.; Negri, P.; Petrovykh, L.; Terranova, F.; Dharmasiri, D.R.; Nossum, B.; Read, A.L.; Skaali, B.; Rohne, O.; Castellani, L.; Pegoraro, M.; Fenyuk, A.; Ivanyushenkov, I.; Karyukhin, A.; Konopliannikov, A.; Shalanda, N.; Sen'ko, V.; Vlasov, E.; Zaitsev, A.; Bigi, M.; Cassio, V.; Gamba, D.; Gouz, I.; Migliore, E.; Romero, A.; Simonetti, L.; Trapani, P.P.; Bari, M.; Della Ricca, G.; Lanceri, L.; Poropat, P.; Prest, M.

    1997-01-01

    The STIC calorimeter was installed in the DELPHI detector in 1994. The main goal is to measure the luminosity with an accuracy better than 0.1%. The calorimeter was built using the ''Shashlik'' technique. The light is collected by wavelength shifting fibers and readout by phototetrodes that can operate inside the magnetic field. The detector performance during the 1994-1995 data taking is presented. The different contributions to the systematic error on the luminosity measurement are discussed. (orig.)

  1. High-precision photometry by telescope defocussing - VI. WASP-24, WASP-25 and WASP-26

    Southworth, John; Hinse, T. C.; Burgdorf, M.

    2014-01-01

    We present time series photometric observations of 13 transits in the planetary systems WASP-24, WASP-25 and WASP-26. All three systems have orbital obliquity measurements, WASP-24 and WASP-26 have been observed with Spitzer, and WASP-25 was previously comparatively neglected. Our light curves we...

  2. TOWARD CHARACTERIZATION OF THE TYPE IIP SUPERNOVA PROGENITOR POPULATION: A STATISTICAL SAMPLE OF LIGHT CURVES FROM Pan-STARRS1

    Sanders, N. E.; Soderberg, A. M.; Chornock, R.; Berger, E.; Challis, P.; Drout, M.; Kirshner, R. P.; Lunnan, R.; Marion, G. H.; Margutti, R.; McKinnon, R.; Milisavljevic, D. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Gezari, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Betancourt, M. [Department of Statistics, University of Warwick, Coventry (United Kingdom); Foley, R. J. [Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Narayan, G. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Rest, A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Kankare, E.; Mattila, S. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, 21500 Piikkiö (Finland); Smartt, S. J., E-mail: nsanders@cfa.harvard.edu [Astrophysics Research Centre, School of Mathematics and Physics, Queens University, BT7 1NN, Belfast (United Kingdom); and others

    2015-02-01

    In recent years, wide-field sky surveys providing deep multiband imaging have presented a new path for indirectly characterizing the progenitor populations of core-collapse supernovae (SNe): systematic light-curve studies. We assemble a set of 76 grizy-band Type IIP SN light curves from Pan-STARRS1, obtained over a constant survey program of 4 yr and classified using both spectroscopy and machine-learning-based photometric techniques. We develop and apply a new Bayesian model for the full multiband evolution of each light curve in the sample. We find no evidence of a subpopulation of fast-declining explosions (historically referred to as ''Type IIL'' SNe). However, we identify a highly significant relation between the plateau phase decay rate and peak luminosity among our SNe IIP. These results argue in favor of a single parameter, likely determined by initial stellar mass, predominantly controlling the explosions of red supergiants. This relation could also be applied for SN cosmology, offering a standardizable candle good to an intrinsic scatter of ≲ 0.2 mag. We compare each light curve to physical models from hydrodynamic simulations to estimate progenitor initial masses and other properties of the Pan-STARRS1 Type IIP SN sample. We show that correction of systematic discrepancies between modeled and observed SN IIP light-curve properties and an expanded grid of progenitor properties are needed to enable robust progenitor inferences from multiband light-curve samples of this kind. This work will serve as a pathfinder for photometric studies of core-collapse SNe to be conducted through future wide-field transient searches.

  3. Efficient dye-sensitized solar cells from curved silicate microsheet caged TiO2 photoanodes. An avenue of enhancing light harvesting

    Wang, Zubin; Tang, Qunwei; He, Benlin; Chen, Haiyan; Yu, Liangmin

    2015-01-01

    Graphical abstract: - Highlights: • Curved silicate microsheets are incorporated with TiO 2 for light harvesting in DSSC • The optical matching between silicate and TiO 2 is superior to light reflection. • The curved silicate can hinder the recombination reaction of electrons with I 3 − . • The DSSC with TiO 2 /curved silicate photoanode shows an efficiency of 9.22% - Abstract: Enhancement of light harvesting has been a persistent objective for elevating dye excitation and therefore power conversion efficiency of dye-sensitized solar cells (DSSCs). Here we launch a strategy of markedly enhancing light harvesting by caging TiO 2 nanoparticles with curved silica microsheets. The results show that the strategy is versatile in suppressing the recombination reaction of electrons with I 3 − species in liquid electrolyte. Due to the superior reflective behaviors of curved silica microsheets, an optimal efficiency of 9.22% is recorded under simulated air mass 1.5 global sunlight on the DSSC in comparison with 6.51% and 7.51% from pristine TiO 2 and planar silicate microsheet incorporated TiO 2 photoanode based solar cells, respectively. This strategy is also believed to be applicable to other solar cells such as perovskite solar cells and quantum dot-sensitized solar cells.

  4. The development of high precision 14C measurement and its application to archaeological time-scale problems

    Pearson, G.W.

    1983-01-01

    High precision calibration curve of some 6000 years has been constructed from the measurement of contiguous 20 year samples of dendrochronologically dated Irish oak. 14 C evidence was presented using a 'wiggle' matching technique which supported the dendrochronological fixing of the BC period Irish oak chronology. Two archaeological samples were 'wiggle matched' to give a calendar age within a range of 25 years and proved that this technique is as precise as dendrochronological dating and is potentially as useful for a much wider range of samples and growth periods. (author)

  5. Light-curve analysis of KOI 2700b: the second extrasolar planet with a comet-like tail

    Garai, Z.

    2018-03-01

    Context. The Kepler object KOI 2700b (KIC 8639908b) was discovered recently as the second exoplanet with a comet-like tail. It exhibits a distinctly asymmetric transit profile, likely indicative of the emission of dusty effluents and reminiscent of KIC 12557548b, the first exoplanet with a comet-like tail. Aim. The scientific goal of this work is to verify the disintegrating-planet scenario of KOI 2700b by modeling its light curve and to put constraints on various tail and planet properties, as was done in the case of KIC 12557548b. Methods: We obtained the phase-folded and binned transit light curve of KOI 2700b, which we subsequently iteratively modeled using the radiative-transfer code SHELLSPEC. We modeled the comet-like tail as part of a ring around the parent star and we also included the solid body of the planet in the model. During the modeling we applied selected species and dust particle sizes. Results: We confirmed the disintegrating-planet scenario of KOI 2700b. Furthermore, via modeling, we derived some interesting features of KOI 2700b and its comet-like tail. It turns out that the orbital plane of the planet and its tail are not edge-on, but the orbital inclination angle is from the interval [85.1, 88.6] deg. In comparison with KIC 12557548b, KOI 2700b exhibits a relatively low dust density decreasing in its tail. We also derived the dust density at the beginning of the ring and the highest optical depth through the tail in front of the star, based on a tail-model with a cross-section of 0.05 × 0.05 R⊙ at the beginning and 0.09 × 0.09 R⊙ at its end. Our results show that the dimension of the planet is Rp/Rs ≤ 0.014 (Rp ≤ 0.871 R⊕, or ≤5551 km). We also estimated the mass-loss rate from KOI 2700b, and we obtained Ṁ values from the interval [5.05 × 107, 4.41 × 1015] g s-1. On the other hand, we could not draw any satisfactory conclusions about the typical grain size in the dust tail.

  6. "TNOs are Cool": A survey of the trans-Neptunian region. XII. Thermal light curves of Haumea, 2003 VS2 and 2003 AZ84 with Herschel/PACS

    Santos-Sanz, P.; Lellouch, E.; Groussin, O.; Lacerda, P.; Müller, T. G.; Ortiz, J. L.; Kiss, C.; Vilenius, E.; Stansberry, J.; Duffard, R.; Fornasier, S.; Jorda, L.; Thirouin, A.

    2017-08-01

    Context. Time series observations of the dwarf planet Haumea and the Plutinos 2003 VS2 and 2003 AZ84 with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects (TNOs) were acquired as part of the "TNOs are Cool" Herschel Space Observatory key programme. Aims: We search for the thermal light curves at 100 and 160 μm of Haumea and 2003 AZ84, and at 70 and 160 μm for 2003 VS2 by means of photometric analysis of the PACS data. The goal of this work is to use these thermal light curves to obtain physical and thermophysical properties of these icy Solar System bodies. Methods: When a thermal light curve is detected, it is possible to derive or constrain the object thermal inertia, phase integral and/or surface roughness with thermophysical modeling. Results: Haumea's thermal light curve is clearly detected at 100 and 160 μm. The effect of the reported dark spot is apparent at 100 μm. Different thermophysical models were applied to these light curves, varying the thermophysical properties of the surface within and outside the spot. Although no model gives a perfect fit to the thermal observations, results imply an extremely low thermal inertia (0.73) for Haumea's surface. We note that the dark spot region appears to be only weakly different from the rest of the object, with modest changes in thermal inertia and/or phase integral. The thermal light curve of 2003 VS2 is not firmly detected at 70 μm and at 160 μm but a thermal inertia of (2 ± 0.5) MKS can be derived from these data. The thermal light curve of 2003 AZ84 is not firmly detected at 100 μm. We apply a thermophysical model to the mean thermal fluxes and to all the Herschel/PACS and Spitzer/MIPS thermal data of 2003 AZ84, obtaining a close to pole-on orientation as the most likely for this TNO. Conclusions: For the three TNOs, the thermal inertias derived from light curve analyses or from the thermophysical analysis of the mean thermal fluxes confirm the generally small

  7. Injection molding of high precision optics for LED applications made of liquid silicone rubber

    Hopmann, Christian; Röbig, Malte [Institute of Plastics Processing (IKV), RWTH Aachen University, Pontstraße 49, 52062 Aachen (Germany)

    2016-03-09

    Light Emitting Diodes (LED) conquer the growing global market of lighting technologies. Due to their advantages, they are increasingly used in consumer products, in lighting applications in the home and in the mobility sector as well as in industrial applications. Particularly, with regard to the increasing use of high-power LED (HP-LED) the materials in the surrounding area of the light emitting semiconductor chip are of utmost importance. While the materials behind the semiconductor chip are optimized for maximum heat dissipation, the materials currently used for the encapsulation of the semiconductor chip (primary optics) and the secondary optics encounter their limits due to the high temperatures. In addition certain amounts of blue UV radiation degrade the currently used materials such as epoxy resins or polyurethanes for primary optics. In the context of an ongoing joint research project with various partners from the industry, an innovative manufacturing method for high precision optics for LED applications made of liquid silicone rubber (LSR) is analyzed at the Institut of Plastics Processing (IKV), Aachen. The aim of this project is to utilize the material-specific advantages of high transparent LSR, especially the excellent high temperature resistance and the great freedom in design. Therefore, a high integrated injection molding process is developed. For the production of combined LED primary and secondary optics a LED board is placed in an injection mold and overmolded with LSR. Due to the integrated process and the reduction of subcomponents like the secondary optics the economics of the production process can be improved significantly. Furthermore combined LED optics offer an improved effectiveness, because there are no losses of the light power at the transition of the primary and secondary optics.

  8. MULTI-COLOR OPTICAL AND NEAR-INFRARED LIGHT CURVES OF 64 STRIPPED-ENVELOPE CORE-COLLAPSE SUPERNOVAE

    Bianco, F. B.; Modjaz, M. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Hicken, M.; Friedman, A.; Kirshner, R. P.; Challis, P.; Marion, G. H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bloom, J. S. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Wood-Vasey, W. M. [PITT PACC, Department of Physics and Astronomy, 3941 O' Hara Street, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Rest, A., E-mail: fb55@nyu.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-08-01

    We present a densely sampled, homogeneous set of light curves of 64 low-redshift (z ≲ 0.05) stripped-envelope supernovae (SNe of Type IIb, Ib, Ic, and Ic-BL). These data were obtained between 2001 and 2009 at the Fred L. Whipple Observatory (FLWO) on Mount Hopkins in Arizona, with the optical FLWO 1.2 m and the near-infrared (NIR) Peters Automated Infrared 1.3 m telescopes. Our data set consists of 4543 optical photometric measurements on 61 SNe, including a combination of U BV RI, U BV r{sup ′}i{sup ′}, and u{sup ′} BV r{sup ′}i{sup ′}, and 1919 JHK{sub s} NIR measurements on 25 SNe. This sample constitutes the most extensive multi-color data set of stripped-envelope SNe to date. Our photometry is based on template-subtracted images to eliminate any potential host-galaxy light contamination. This work presents these photometric data, compares them with data in the literature, and estimates basic statistical quantities: date of maximum, color, and photometric properties. We identify promising color trends that may permit the identification of stripped-envelope SN subtypes from their photometry alone. Many of these SNe were observed spectroscopically by the Harvard-Smithsonian Center for Astrophysics (CfA) SN group, and the spectra are presented in a companion paper. A thorough exploration that combines the CfA photometry and spectroscopy of stripped-envelope core-collapse SNe will be presented in a follow-up paper.

  9. Parton distributions from high-precision collider data

    Ball, Richard D.; Del Debbio, Luigi; Groth-Merrild, Patrick [University of Edinburgh, The Higgs Centre for Theoretical Physics, Edinburgh (United Kingdom); Bertone, Valerio; Hartland, Nathan P.; Rojo, Juan [VU University, Department of Physics and Astronomy, Amsterdam (Netherlands); Nikhef Theory Group, Amsterdam (Netherlands); Carrazza, Stefano [CERN, Theoretical Physics Department, Geneva (Switzerland); Forte, Stefano [Universita di Milano, Tif Lab, Dipartimento di Fisica, Milano (Italy); INFN, Sezione di Milano, Milano (Italy); Guffanti, Alberto [Universita di Torino, Dipartimento di Fisica, Turin (Italy); INFN, Sezione di Torino, Turin (Italy); Kassabov, Zahari [Universita di Milano, Tif Lab, Dipartimento di Fisica, Milano (Italy); INFN, Sezione di Milano, Milano (Italy); Universita di Torino, Dipartimento di Fisica, Turin (Italy); INFN, Sezione di Torino, Turin (Italy); Latorre, Jose I. [Universitat de Barcelona, Departament de Fisica Quantica i Astrofisica, Barcelona (Spain); National University of Singapore, Center for Quantum Technologies, Singapore (Singapore); Nocera, Emanuele R.; Rottoli, Luca; Slade, Emma [University of Oxford, Rudolf Peierls Centre for Theoretical Physics, Oxford (United Kingdom); Ubiali, Maria [University of Cambridge, Cavendish Laboratory, HEP Group, Cambridge (United Kingdom); Collaboration: NNPDF Collaboration

    2017-10-15

    We present a new set of parton distributions, NNPDF3.1, which updates NNPDF3.0, the first global set of PDFs determined using a methodology validated by a closure test. The update is motivated by recent progress in methodology and available data, and involves both. On the methodological side, we now parametrize and determine the charm PDF alongside the light-quark and gluon ones, thereby increasing from seven to eight the number of independent PDFs. On the data side, we now include the D0 electron and muon W asymmetries from the final Tevatron dataset, the complete LHCb measurements of W and Z production in the forward region at 7 and 8 TeV, and new ATLAS and CMS measurements of inclusive jet and electroweak boson production. We also include for the first time top-quark pair differential distributions and the transverse momentum of the Z bosons from ATLAS and CMS. We investigate the impact of parametrizing charm and provide evidence that the accuracy and stability of the PDFs are thereby improved. We study the impact of the new data by producing a variety of determinations based on reduced datasets. We find that both improvements have a significant impact on the PDFs, with some substantial reductions in uncertainties, but with the new PDFs generally in agreement with the previous set at the one-sigma level. The most significant changes are seen in the light-quark flavor separation, and in increased precision in the determination of the gluon. We explore the implications of NNPDF3.1 for LHC phenomenology at Run II, compare with recent LHC measurements at 13 TeV, provide updated predictions for Higgs production cross-sections and discuss the strangeness and charm content of the proton in light of our improved dataset and methodology. The NNPDF3.1 PDFs are delivered for the first time both as Hessian sets, and as optimized Monte Carlo sets with a compressed number of replicas. (orig.)

  10. Noise reduction methods in the analysis of near infrared lunar occultation light curves for high angular resolution measurements

    Baug Tapas; Chandrasekhar Thyagarajan

    2013-01-01

    A lunar occultation (LO) technique in the near-infrared (NIR) provides angular resolution down to milliarcseconds for an occulted source, even with ground-based 1 m class telescopes. LO observations are limited to brighter objects because they require a high signal-to-noise ratio (S/N ∼40) for proper extraction of angular diameter values. Hence, methods to improve the S/N ratio by reducing noise using Fourier and wavelet transforms have been explored in this study. A sample of 54 NIR LO light curves observed with the IR camera at Mt Abu Observatory has been used. It is seen that both Fourier and wavelet methods have shown an improvement in S/N compared to the original data. However, the application of wavelet transforms causes a slight smoothing of the fringes and results in a higher value for angular diameter. Fourier transforms which reduce discrete noise frequencies do not distort the fringe. The Fourier transform method seems to be effective in improving the S/N, as well as improving the model fit, particularly in the fainter regime of our sample. These methods also provide a better model fit for brighter sources in some cases, though there may not be a significant improvement in S/N

  11. A Hybrid Algorithm for Period Analysis from Multiband Data with Sparse and Irregular Sampling for Arbitrary Light-curve Shapes

    Saha, Abhijit; Vivas, A. Katherina

    2017-12-01

    Ongoing and future surveys with repeat imaging in multiple bands are producing (or will produce) time-spaced measurements of brightness, resulting in the identification of large numbers of variable sources in the sky. A large fraction of these are periodic variables: compilations of these are of scientific interest for a variety of purposes. Unavoidably, the data sets from many such surveys not only have sparse sampling, but also have embedded frequencies in the observing cadence that beat against the natural periodicities of any object under investigation. Such limitations can make period determination ambiguous and uncertain. For multiband data sets with asynchronous measurements in multiple passbands, we wish to maximally use the information on periodicity in a manner that is agnostic of differences in the light-curve shapes across the different channels. Given large volumes of data, computational efficiency is also at a premium. This paper develops and presents a computationally economic method for determining periodicity that combines the results from two different classes of period-determination algorithms. The underlying principles are illustrated through examples. The effectiveness of this approach for combining asynchronously sampled measurements in multiple observables that share an underlying fundamental frequency is also demonstrated.

  12. An Optical Low-frequency Quasi-Periodic Oscillation in the Kepler Light Curve of an Active Galaxy

    Mushotzky, Richard; Smith, Krista Lynne; Boyd, Patricia; Wagoner, Robert

    2018-01-01

    We report the discovery of a candidate quasi-periodic oscillation (QPO) in the optical light curve of KIC 9650712, a Seyfert 1 galaxy in the original Kepler field. After the development and application of a pipeline for Kepler data specific to active galactic nuclei (AGN), one of our sample of 21 AGN selected by infrared photometry and X-ray flux demonstrates a peak in the power spectrum at 10-6.58 Hz, corresponding to a temporal period of 44 days. >From optical spectroscopy, we measure the black hole mass of this AGN as log M = 8.17 M_sun. Despite this high mass, the optical spectrum of KIC 9650712 bears many similarities to Narrow Line Seyfert 1 (NLS1) galaxies, including strong Fe II emission and a low [O III]/Hβ ratio. So far, X-ray QPOs have primarily been seen in NLS1 galaxies. Finally, we find that this frequency lies along a correlation between low-frequency QPOs and black hole mass from stellar and intermediate mass black holes to AGN, similar to the known correlation in high-frequency QPOs.

  13. Light curve solutions and study of roles of magnetic fields in period variations of the UV Leo system

    D Manzoori

    2009-12-01

    Full Text Available The solutions of photometric BV light curves for the Algol like system UV Leo were obtained using Wilson-Devinney code. The physical and orbital parameters along with absolute dimensions of the system were determined. It has been found that to best fit the V light curve of the system, assumptions of three dark spots were necessary two on the secondary and one on the primary. The absolute visual magnitudes (Mv of the individual components i.e., primary and secondary were estimated to 4.41 and 4.43, respectively, through the color curve analysis. The period analysis of the system presented elsewhere, indicated a cyclic period change of 12 yr duration, which was attributed to magnetic activity cycle, as a main cause of period variation in the system, through the Applegate mechanism. To verify the Applegate model I preformed calculations of some related parameters barrowed from Apllegate and Kalimeris. Values of all the calculated parameters were in accordance to those obtained for similar systems by Applegate. The differential magnitudes Δ B and Δ V, along with corresponding values of Δ(B-V color index. The cyclic variations in brightness are quite clear. There are three predictions of Applegate's theory concerning effects of cyclic magnetic changes on the period variations, which can be checked through the observations, these are as follows: I The long term variations in mean brightness (at outside of eclipses and cyclic changes of orbital period, vary with the same period. II The active star gets bluer as it gets brightened and/or the brightness and color variations are to be in phase. III Changes in luminosity due to changes in quadrupole moment should be of the order 0.1 mag. All the above mentioned predictions of Applegate’s theory are verified. These results combined with cyclic character of P(E presented elsewhere and also consistency of parameters which are obtained in this paper, led me to conclude that one the main causes of period

  14. High precision spectroscopy of pionic and antiprotonic atoms; Spectroscopie de precision des atomes pioniques et antiprotoniques

    El-Khoury, P

    1998-04-15

    The study of exotic atoms, in which an orbiting electron of a normal atom is replaced by a negatively charged particle ({pi}{sup -}, {mu}{sup -}, p, {kappa}{sup -}, {sigma}{sup -},...) may provide information on the orbiting particle and the atomic nucleus, as well as on their interaction. In this work, we were interested in pionic atoms ({pi}{sup -14} N) on the one hand in order to determine the pion mass with high accuracy (4 ppm), and on the other hand in antiprotonic atoms (pp-bar) in order to study the strong nucleon-antinucleon interaction at threshold. In this respect, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high stop density for particles in gas targets at low pressure. Using curved crystals, an extended X-ray source could be imaged onto the detector. Charge-Coupled Devices were used as position sensitive detectors in order to measure the Bragg angle of the transition to a high precision. The use of gas targets resolved the ambiguity owing to the number of K electrons for the value of the pion mass, and, for the first time, strong interaction shift and broadening of the 2p level in antiprotonic hydrogen were measured directly. (author)

  15. High precision laser processing of sensitive materials by Microjet

    Sibailly, Ochelio D.; Wagner, Frank R.; Mayor, Laetitia; Richerzhagen, Bernold

    2003-11-01

    Material laser cutting is well known and widely used in industrial processes, including micro fabrication. An increasing number of applications require nevertheless a superior machining quality than can be achieved using this method. A possibility to increase the cut quality is to opt for the water-jet guided laser technology. In this technique the laser is conducted to the work piece by total internal reflection in a thin stable water-jet, comparable to the core of an optical fiber. The water jet guided laser technique was developed originally in order to reduce the heat damaged zone near the cut, but in fact many other advantages were observed due to the usage of a water-jet instead of an assist gas stream applied in conventional laser cutting. In brief, the advantages are three-fold: the absence of divergence due to light guiding, the efficient melt expulsion, and optimum work piece cooling. In this presentation we will give an overview on several industrial applications of the water-jet guided laser technique. These applications range from the cutting of CBN or ferrite cores to the dicing of thin wafers and the manufacturing of stencils, each illustrates the important impact of the water-jet usage.

  16. Temporal Evolution of the Gamma-ray Burst Afterglow Spectrum for an Observer: GeV–TeV Synchrotron Self-Compton Light Curve

    Fukushima, Takuma; Fujita, Yutaka [Department of Earth and Space Science, Osaka University, Osaka, 560-0043 (Japan); To, Sho; Asano, Katsuaki, E-mail: fukushima@vega.ess.sci.osaka-u.ac.jp, E-mail: fujita@vega.ess.sci.osaka-u.ac.jp, E-mail: tosho@icrr.u-tokyo.ac.jp, E-mail: asanok@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)

    2017-08-01

    We numerically simulate the gamma-ray burst (GRB) afterglow emission with a one-zone time-dependent code. The temporal evolutions of the decelerating shocked shell and energy distributions of electrons and photons are consistently calculated. The photon spectrum and light curves for an observer are obtained taking into account the relativistic propagation of the shocked shell and the curvature of the emission surface. We find that the onset time of the afterglow is significantly earlier than the previous analytical estimate. The analytical formulae of the shock propagation and light curve for the radiative case are also different from our results. Our results show that even if the emission mechanism is switching from synchrotron to synchrotron self-Compton, the gamma-ray light curves can be a smooth power law, which agrees with the observed light curve and the late detection of a 32 GeV photon in GRB 130427A. The uncertainty of the model parameters obtained with the analytical formula is discussed, especially in connection with the closure relation between spectral index and decay index.

  17. An analysis of the small amplitude variations in the light curves of the R Coronae Borealis variables, S Apodis and UW Centauri

    Kilkenny, D.; Flanagan, C.

    1983-01-01

    The small amplitude variations in the light curves of the R CrB stars, S Aps and UW Cen, are examined. The periodicity of these variations appears to be changing rapidly in S Aps and slowly, if at all, in UW Cen. The evolutionary consequences of these effects are discussed. (author)

  18. Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

    An, Hongjun; Romani, Roger W., E-mail: hjan@chungbuk.ac.kr [Department of Physics/KIPAC, Stanford University, Stanford, CA 94305-4060 (United States)

    2017-04-01

    We present broadband spectral energy distributions and light curves of the gamma-ray binary 1FGL J1018.6−5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explain the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. The model requires an inclination of ∼50° and an orbital eccentricity of ∼0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.

  19. A high-precision system for conformal intracranial radiotherapy

    Tome, Wolfgang A.; Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Li Zuofeng

    2000-01-01

    Purpose: Currently, optimally precise delivery of intracranial radiotherapy is possible with stereotactic radiosurgery and fractionated stereotactic radiotherapy. We report on an optimally precise optically guided system for three-dimensional (3D) conformal radiotherapy using multiple noncoplanar fixed fields. Methods and Materials: The optically guided system detects infrared light emitting diodes (IRLEDs) attached to a custom bite plate linked to the patient's maxillary dentition. The IRLEDs are monitored by a commercially available stereo camera system, which is interfaced to a personal computer. An IRLED reference is established with the patient at the selected stereotactic isocenter, and the computer reports the patient's current position based on the location of the IRLEDs relative to this reference position. Using this readout from the computer, the patient may be dialed directly to the desired position in stereotactic space. The patient is localized on the first day and a reference file is established for 5 different couch positions. The patient's image data are then imported into a commercial convolution-based 3D radiotherapy planning system. The previously established isocenter and couch positions are then used as a template upon which to design a conformal 3D plan with maximum beam separation. Results: The use of the optically guided system in conjunction with noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit a high degree of dose homogeneity and a steep dose gradient. To date, this approach has been used to treat 28 patients. Conclusion: Because IRLED technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, one can choose treatment-field margins that only account for beam penumbra and image resolution without adding margin to account for larger and poorly defined setup uncertainty. This

  20. LIGHT CURVES OF CORE-COLLAPSE SUPERNOVAE WITH SUBSTANTIAL MASS LOSS USING THE NEW OPEN-SOURCE SUPERNOVA EXPLOSION CODE (SNEC)

    Morozova, Viktoriya; Renzo, Mathieu; Ott, Christian D.; Clausen, Drew; Couch, Sean M.; Ellis, Justin; Roberts, Luke F.; Piro, Anthony L.

    2015-01-01

    We present the SuperNova Explosion Code (SNEC), an open-source Lagrangian code for the hydrodynamics and equilibrium-diffusion radiation transport in the expanding envelopes of supernovae. Given a model of a progenitor star, an explosion energy, and an amount and distribution of radioactive nickel, SNEC generates the bolometric light curve, as well as the light curves in different broad bands assuming blackbody emission. As a first application of SNEC, we consider the explosions of a grid of 15 M ⊙ (at zero-age main sequence, ZAMS) stars whose hydrogen envelopes are stripped to different extents and at different points in their evolution. The resulting light curves exhibit plateaus with durations of ∼20–100 days if ≳1.5–2 M ⊙ of hydrogen-rich material is left and no plateau if less hydrogen-rich material is left. If these shorter plateau lengths are not seen for SNe IIP in nature, it suggests that, at least for ZAMS masses ≲20 M ⊙ , hydrogen mass loss occurs as an all or nothing process. This perhaps points to the important role binary interactions play in generating the observed mass-stripped supernovae (i.e., Type Ib/c events). These light curves are also unlike what is typically seen for SNe IIL, arguing that simply varying the amount of mass loss cannot explain these events. The most stripped models begin to show double-peaked light curves similar to what is often seen for SNe IIb, confirming previous work that these supernovae can come from progenitors that have a small amount of hydrogen and a radius of ∼500 R ⊙

  1. LIGHT CURVES OF CORE-COLLAPSE SUPERNOVAE WITH SUBSTANTIAL MASS LOSS USING THE NEW OPEN-SOURCE SUPERNOVA EXPLOSION CODE (SNEC)

    Morozova, Viktoriya; Renzo, Mathieu; Ott, Christian D.; Clausen, Drew; Couch, Sean M.; Ellis, Justin; Roberts, Luke F. [TAPIR, Walter Burke Institute for Theoretical Physics, MC 350-17, California Institute of Technology, Pasadena, CA 91125 (United States); Piro, Anthony L., E-mail: morozvs@tapir.caltech.edu [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)

    2015-11-20

    We present the SuperNova Explosion Code (SNEC), an open-source Lagrangian code for the hydrodynamics and equilibrium-diffusion radiation transport in the expanding envelopes of supernovae. Given a model of a progenitor star, an explosion energy, and an amount and distribution of radioactive nickel, SNEC generates the bolometric light curve, as well as the light curves in different broad bands assuming blackbody emission. As a first application of SNEC, we consider the explosions of a grid of 15 M{sub ⊙} (at zero-age main sequence, ZAMS) stars whose hydrogen envelopes are stripped to different extents and at different points in their evolution. The resulting light curves exhibit plateaus with durations of ∼20–100 days if ≳1.5–2 M{sub ⊙} of hydrogen-rich material is left and no plateau if less hydrogen-rich material is left. If these shorter plateau lengths are not seen for SNe IIP in nature, it suggests that, at least for ZAMS masses ≲20 M{sub ⊙}, hydrogen mass loss occurs as an all or nothing process. This perhaps points to the important role binary interactions play in generating the observed mass-stripped supernovae (i.e., Type Ib/c events). These light curves are also unlike what is typically seen for SNe IIL, arguing that simply varying the amount of mass loss cannot explain these events. The most stripped models begin to show double-peaked light curves similar to what is often seen for SNe IIb, confirming previous work that these supernovae can come from progenitors that have a small amount of hydrogen and a radius of ∼500 R{sub ⊙}.

  2. A JET BREAK IN THE X-RAY LIGHT CURVE OF SHORT GRB 111020A: IMPLICATIONS FOR ENERGETICS AND RATES

    Fong, W.; Berger, E.; Margutti, R.; Zauderer, B. A.; Czekala, I.; Chornock, R.; Troja, E.; Gehrels, N.; Sakamoto, T.; Fox, D. B.; Podsiadlowski, P.

    2012-01-01

    We present broadband observations of the afterglow and environment of the short GRB 111020A. An extensive X-ray light curve from Swift/XRT, XMM-Newton, and Chandra, spanning ∼100 s to 10 days after the burst, reveals a significant break at δt ≈ 2 days with pre- and post-break decline rates of α X,1 ≈ –0.78 and α X,2 ∼ j ≈ 3°-8°. The resulting beaming-corrected γ-ray (10-1000 keV band) and blast-wave kinetic energies are (2-3) × 10 48 erg and (0.3-2) × 10 49 erg, respectively, with the range depending on the unknown redshift of the burst. We report a radio afterglow limit of c X , constrains the circumburst density to n 0 ∼ 0.01-0.1 cm –3 . Optical observations provide an afterglow limit of i ∼> 24.4 mag at 18 hr after the burst and reveal a potential host galaxy with i ≈ 24.3 mag. The subarcsecond localization from Chandra provides a precise offset of 0.''80 ± 0.''11 (1σ) from this galaxy corresponding to an offset of 5-7 kpc for z 0.5-1.5. We find a high excess neutral hydrogen column density of (7.5 ± 2.0) × 10 21 cm –2 (z = 0). Our observations demonstrate that a growing fraction of short gamma-ray bursts (GRBs) are collimated, which may lead to a true event rate of ∼> 100-1000 Gpc –3 yr –1 , in good agreement with the NS-NS merger rate of ≈200-3000 Gpc –3 yr –1 . This consistency is promising for coincident short GRB-gravitational wave searches in the forthcoming era of Advanced LIGO/VIRGO.

  3. Rotation of cometary nuclei: new light curves and an update of the ensemble properties of Jupiter-family comets

    Kokotanekova, R.; Snodgrass, C.; Lacerda, P.; Green, S. F.; Lowry, S. C.; Fernández, Y. R.; Tubiana, C.; Fitzsimmons, A.; Hsieh, H. H.

    2017-11-01

    We report new light curves and phase functions for nine Jupiter-family comets (JFCs). They were observed in the period 2004-2015 with various ground telescopes as part of the Survey of Ensemble Physical Properties of Cometary Nuclei as well as during devoted observing campaigns. We add to this a review of the properties of 35 JFCs with previously published rotation properties. The photometric time series were obtained in Bessel R, Harris R and SDSS r΄ filters and were absolutely calibrated using stars from the Pan-STARRS survey. This specially developed method allowed us to combine data sets taken at different epochs and instruments with absolute-calibration uncertainty down to 0.02 mag. We used the resulting time series to improve the rotation periods for comets 14P/Wolf, 47P/Ashbrook-Jackson, 94P/Russell and 110P/Hartley 3 and to determine the rotation rates of comets 93P/Lovas and 162P/Siding Spring for the first time. In addition to this, we determined the phase functions for seven of the examined comets and derived geometric albedos for eight of them. We confirm the known cut-off in bulk densities at ˜0.6 g cm-3 if JFCs are strengthless. Using a model for prolate ellipsoids with typical density and elongations, we conclude that none of the known JFCs requires tensile strength larger than 10-25 Pa to remain stable against rotational instabilities. We find evidence for an increasing linear phase function coefficient with increasing geometric albedo. The median linear phase function coefficient for JFCs is 0.046 mag deg-1 and the median geometric albedo is 4.2 per cent.

  4. Light mirror reflection combined with heating/cooling curves as a method of studying phase transitions in transparent and opaque petroleum products: Apparatus and theory

    Shishkin, Yu.L.

    2007-01-01

    A portable low weight low cost apparatus 'Phasafot' and method for determining pour and cloud points of petroleum products, as well as precipitation and melting temperatures of paraffins in both transparent (diesel fuels), semi-transparent (lube oils) and opaque (crude oils) samples are described. The method consists in illuminating the surface of a sample with an oblique light beam and registering the intensity of specularly reflected light while heating/cooling the sample in the temperature range of its structural transitions. The mirror reflection of a light beam from an ideally smooth liquid surface falls in intensity when the surface becomes rough (dim) due to crystal formation. Simultaneous recording of the temperature ramp curve and the mirror reflection curve enables the determination of the beginning and end of crystallization of paraffins in both transparent and opaque petroleum products. Besides, their rheological properties can be accurately determined by rocking or tilting the instrument while monitoring the sample movement via its mirror reflection

  5. AEOLUS: A MARKOV CHAIN MONTE CARLO CODE FOR MAPPING ULTRACOOL ATMOSPHERES. AN APPLICATION ON JUPITER AND BROWN DWARF HST LIGHT CURVES

    Karalidi, Theodora; Apai, Dániel; Schneider, Glenn; Hanson, Jake R. [Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Pasachoff, Jay M., E-mail: tkaralidi@email.arizona.edu [Hopkins Observatory, Williams College, 33 Lab Campus Drive, Williamstown, MA 01267 (United States)

    2015-11-20

    Deducing the cloud cover and its temporal evolution from the observed planetary spectra and phase curves can give us major insight into the atmospheric dynamics. In this paper, we present Aeolus, a Markov chain Monte Carlo code that maps the structure of brown dwarf and other ultracool atmospheres. We validated Aeolus on a set of unique Jupiter Hubble Space Telescope (HST) light curves. Aeolus accurately retrieves the properties of the major features of the Jovian atmosphere, such as the Great Red Spot and a major 5 μm hot spot. Aeolus is the first mapping code validated on actual observations of a giant planet over a full rotational period. For this study, we applied Aeolus to J- and H-band HST light curves of 2MASS J21392676+0220226 and 2MASS J0136565+093347. Aeolus retrieves three spots at the top of the atmosphere (per observational wavelength) of these two brown dwarfs, with a surface coverage of 21% ± 3% and 20.3% ± 1.5%, respectively. The Jupiter HST light curves will be publicly available via ADS/VIZIR.

  6. Bragg Curve Spectroscopy

    Gruhn, C.R.

    1981-05-01

    An alternative utilization is presented for the gaseous ionization chamber in the detection of energetic heavy ions, which is called Bragg Curve Spectroscopy (BCS). Conceptually, BCS involves using the maximum data available from the Bragg curve of the stopping heavy ion (HI) for purposes of identifying the particle and measuring its energy. A detector has been designed that measures the Bragg curve with high precision. From the Bragg curve the range from the length of the track, the total energy from the integral of the specific ionization over the track, the dE/dx from the specific ionization at the beginning of the track, and the Bragg peak from the maximum of the specific ionization of the HI are determined. This last signal measures the atomic number, Z, of the HI unambiguously

  7. A CENSUS OF ROTATION AND VARIABILITY IN L1495: A UNIFORM ANALYSIS OF TRANS-ATLANTIC EXOPLANET SURVEY LIGHT CURVES FOR PRE-MAIN-SEQUENCE STARS IN TAURUS

    Xiao Hongyu; Covey, Kevin R.; Lloyd, James P.; Rebull, Luisa; Charbonneau, David; Mandushev, Georgi; O'Donovan, Francis; Slesnick, Catherine

    2012-01-01

    We analyze light curves obtained by the Trans-atlantic Exoplanet Survey (TrES) for a field centered on the L1495 dark cloud in Taurus. The Spitzer Taurus Legacy Survey catalog identifies 179 bona fide Taurus members within the TrES field; 48 of the known Taurus members are detected by TrES, as well as 26 candidate members identified by the Spitzer Legacy team. We quantify the variability of each star in our sample using the ratio of the standard deviation of the original light curve (σ orig. ) to the standard deviation of a light curve that has been smoothed by 9 or 1001 epochs (σ 9 and σ 1001 , respectively). Known Taurus members typically demonstrate (σ orig. /σ 9 ) orig. /σ 1001 ) orig. /σ 9 ) ∼ 3.0 and (σ orig. /σ 1001 ) ∼ 10, as expected for light curves dominated by unstructured white noise. Of the 74 Taurus members/candidates with TrES light curves, we detect significant variability in 49 sources. Adapting a quantitative metric originally developed to assess the reliability of transit detections, we measure the amount of red and white noise in each light curve and identify 18 known or candidate Taurus members with highly significant period measurements. These appear to be the first periods measured for four of these sources (HD 282276, CX Tau, FP Tau, TrES J042423+265008), and in two other cases, the first non-aliased periods (LkCa 21 and DK Tau AB). For the remainder, the TrES measurements typically agree very well (δP < 1%) with previously reported values. Including periods measured at lower confidence for 15 additional sources, we report periods for 11 objects where no previous periods were found, including 8 confirmed Taurus members. We also identify 10 of the 26 candidate Taurus members that demonstrate variability levels consistent with being bona fide T Tauri stars. A Kolomgorov-Smirnov (K-S) test confirms that these new periods confirm the distinction between the rotation period distributions of stars with and without circumstellar

  8. The university of Florida frameless high-precision stereotactic radiotherapy system

    Bova, Francis J.; Buatti, John M.; Friedman, William A.; Mendenhall, William M.; Yang, Ching-Chong; Liu, Chihray

    1997-01-01

    Purpose: To develop and test a system for high precision fractionated stereotactic radiotherapy that separates immobilization and localization devices. Methods and Materials: Patient localization is achieved through detection and digital registration of an independent bite plate system. The bite plate is made and linked to a set of six infrared light emitting diodes (IRLEDs). These IRLEDs are detected by an infrared camera system that identifies the position of each IRLED within 0.1 to 0.15 mm. Calibration of the camera system defines isocenter and translational X, Y, and Z axes of the stereotactic radiosurgery subsystem and thereby digitally defines the virtual treatment room space in a computer linked to the camera system. Positions of the bite plate's IRLEDs are processed digitally using a computer algorithm so that positional differences between an actual bite plate position and a desired position can be resolved within 0.1 mm of translation (X, Y, and Z distance) and 0.1 degree of rotation. Furthermore, bite plate misalignment can be displayed digitally in real time with translational (x, y, and z) and rotational (roll, pitch, and yaw) parameters for an actual bite plate position. Immobilization is achieved by a custom head mold and thermal plastic mask linked by hook-and-loop fastener tape. The head holder system permits rotational and translational movements for daily treatment positioning based on the bite plate localization system. Initial testing of the localization system was performed on 20 patients treated with radiosurgery. The system was used to treat 11 patients with fractionated stereotactic radiotherapy. Results: Assessment of bite plate localization in radiosurgery patients revealed that the patient's bite plate could be positioned and repositioned within 0.5 ± 0.3 mm (standard deviation). After adjustments, the first 11 patients were treated with the bite plate repositioning error reduced to 0.2 ± 0.1 mm. Conclusions: High precision

  9. Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD – Progress on high precision AMS measurements

    Güttler, D.; Wacker, L.; Kromer, B.; Friedrich, M.; Synal, H.-A.

    2013-01-01

    Oak tree rings from Southern Germany covering the AD 1010–1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the 14 C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25–40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

  10. High precision wavefront control in point spread function engineering for single emitter localization

    Siemons, M.; Hulleman, C. N.; Thorsen, R. Ø.; Smith, C. S.; Stallinga, S.

    2018-04-01

    Point Spread Function (PSF) engineering is used in single emitter localization to measure the emitter position in 3D and possibly other parameters such as the emission color or dipole orientation as well. Advanced PSF models such as spline fits to experimental PSFs or the vectorial PSF model can be used in the corresponding localization algorithms in order to model the intricate spot shape and deformations correctly. The complexity of the optical architecture and fit model makes PSF engineering approaches particularly sensitive to optical aberrations. Here, we present a calibration and alignment protocol for fluorescence microscopes equipped with a spatial light modulator (SLM) with the goal of establishing a wavefront error well below the diffraction limit for optimum application of complex engineered PSFs. We achieve high-precision wavefront control, to a level below 20 m$\\lambda$ wavefront aberration over a 30 minute time window after the calibration procedure, using a separate light path for calibrating the pixel-to-pixel variations of the SLM, and alignment of the SLM with respect to the optical axis and Fourier plane within 3 $\\mu$m ($x/y$) and 100 $\\mu$m ($z$) error. Aberrations are retrieved from a fit of the vectorial PSF model to a bead $z$-stack and compensated with a residual wavefront error comparable to the error of the SLM calibration step. This well-calibrated and corrected setup makes it possible to create complex `3D+$\\lambda$' PSFs that fit very well to the vectorial PSF model. Proof-of-principle bead experiments show precisions below 10~nm in $x$, $y$, and $\\lambda$, and below 20~nm in $z$ over an axial range of 1 $\\mu$m with 2000 signal photons and 12 background photons.

  11. Observations and light curve solutions of the eclipsing binaries USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731

    Kjurkchieva D.

    2016-01-01

    Full Text Available We present follow-up photometric observations in Sloan filters g', i' of the newly discovered eclipsing stars USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731. Our data revealed that their orbital periods are considerably bigger than the previous values. This result changed the classification of USNO-B1.0 1395-0370184 from ultrashort-period binary (P=0.197 d to short-period system (P=0.251 d. The light curve solutions of our observations revealed that USNOB1.0 1395-0370184 and USNO-B1.0 1395-0370731 are overcontact binaries in which components are K dwarfs, close in masses and radii. The light curve distortions were reproduced by cool spots with angular radius of around 20°.

  12. Single Crystal Piezomotor for Large Stroke, High Precision and Cryogenic Actuations, Phase I

    National Aeronautics and Space Administration — TRS Technologies proposes a novel single crystal piezomotor for large stroke, high precision, and cryogenic actuations with capability of position set-hold with...

  13. Drift chambers for a large-area, high-precision muon spectrometer

    Alberini, C.; Bari, G.; Cara Romeo, G.; Cifarelli, L.; Del Papa, C.; Iacobucci, G.; Laurenti, G.; Maccarrone, G.; Massam, T.; Motta, F.; Nania, R.; Perotto, E.; Prisco, G.; Willutsky, M.; Basile, M.; Contin, A.; Palmonari, F.; Sartorelli, G.

    1987-01-01

    We have tested two prototypes of high-precision drift chamber for a magnetic muon spectrometer. Results of the tests are presented, with special emphasis on their efficiency and spatial resolution as a function of particle rate. (orig.)

  14. High-precision analogue peak detector for X-ray imaging applications

    Dlugosz, Rafal Tomasz; Iniewski, Kris

    2007-01-01

    A new analogue high-precision peak detector is presented. Owing to its very low power consumption the circuit is particularly well suited for photon energy detection in multichannel receiver integrated circuits used in nuclear medicine.

  15. Determinations of its Absolute Dimensions and Distance by the Analyses of Light and Radial-Velocity Curves of the Contact Binary -I. V417 Aquilae

    Jae Woo Lee

    2004-06-01

    Full Text Available New photometric and spectroscopic solutions of W-type overcontact binary V417 Aql were obtained by solving the UBV light curves of Samec et al. (1997 and radial-velocity ones of Lu & Rucinski (1999 with the 2003 version of the Wilson-Devinney binary code. In the light curve synthesis the light of a third-body, which Qian (2003 proposed, was considered and obtained about 2.7%, 2.2%, and 0.4% for U, B, and V bandpasses, respectively. The model with third-light is better fitted to eclipse parts than that with no third-light. Absolute dimensions of V417 Aql are determined from our solution as M1=0.53 M⊙, M2=1.45 M⊙, R1=0.84 R⊙ and R2=1.31 M⊙, and the distance to it is deduced as about 216pc. Our distance is well consistent with that (204pc derived from Rucinski & Duerbeck's (1997 relation, MV=MV(log P, B-V, but is more distant than that (131±40pc determined by the Hipparcos trigonometric parallax. The difference may result from the relatively large error of Hipparcos parallax for V417 Aql.

  16. Design, fabrication, and calibration of curved integral coils for measuring transfer function, uniformity, and effective length of LBL ALS [Lawrence Berkeley Laboratory Advanced Light Source] Booster Dipole Magnets

    Green, M.I.; Nelson, D.; Marks, S.; Gee, B.; Wong, W.; Meneghetti, J.

    1989-03-01

    A matched pair of curved integral coils has been designed, fabricated and calibrated at Lawrence Berkeley Laboratory for measuring Advanced Light Source (ALS) Booster Dipole Magnets. Distinctive fabrication and calibration techniques are described. The use of multifilar magnet wire in fabrication integral search coils is described. Procedures used and results of AC and DC measurements of transfer function, effective length and uniformity of the prototype booster dipole magnet are presented in companion papers. 8 refs

  17. Testing the nature of the supermassive black hole candidate in SgrA* with light curves and images of hot spots

    Li, Zilong; Kong, Lingyao; Bambi, Cosimo

    2014-01-01

    General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA*, the supermassive black hole candidate at the center of our Galaxy, and to open a new window to test the Kerr black hole hypothesis. In this paper, we compute light curves and images associated with compact emission regions (hot spots) orbiting around Kerr and non-Kerr black holes. We study how the analysis of the properties of the radiation emitted by a hot spot can be used to test the Kerr nature of SgrA*. We find that the sole observation of the hot spot light curve can at most constrain a combination of the black hole spin and of possible deviations from the Kerr solution. This happens because the same orbital frequency around a Kerr black hole can be found for a non-Kerr object with a different spin parameter. Second order corrections in the light curve due to the background geometry are typically too small to be identified. While the observation of the hot spot centroid track can potentially bound possible deviations from the Kerr solution, that is out of reach for the near future for the Very Large Telescope Interferometer instrument GRAVITY. The Kerr black hole hypothesis could really be tested in the case of the discovery of a radio pulsar in a compact orbit around SgrA*. Radio observations of such a pulsar would provide precise estimates of the mass and the spin of SgrA*, and the combination of these measurements (probing the weak field) with the hot spot light curve information (probing the strong field) may constrain/find possible deviations from the Kerr solution with quite good precision.

  18. Optical light curve of GRB 121011A: a textbook for the onset of GRB afterglow in a mixture of ISM and wind-type medium

    Xin, Li-Ping; Wei, Jian-Yan; Qiu, Yu-Lei; Deng, Jin-Song; Wang, Jing; Han, Xu-Hui

    2016-01-01

    We report the optical observations of GRB 121011A by the 0.8m TNT facility at Xinglong observatory, China. The light curve of the optical afterglow shows a smooth and featureless bump during the epoch of ∼130 s and ∼5000 s with a rising index of 1.57 ± 0.28 before the break time of 539 ± 44 s, and a decaying index of about 1.29 ± 0.07 up to the end of our observations. Moreover, the X-ray light curve decays in a single power-law with a slope of about 1.51 ± 0.03 observed by XRT onboard Swift from 100 s to about 10 000 s after the burst trigger. The featureless optical light curve could be understood as an onset process under the external-shock model. The typical frequency has been below or near the optical one before the deceleration time, and the cooling frequency is located between the optical and X-ray wavelengths. The external medium density has a transition from a mixed stage of ISM and wind-type medium before the peak time to the ISM at the later phase. The joint-analysis of X-ray and optical light curves shows that the emissions from both frequencies are consistent with the prediction of the standard afterglow model without any energy injections, indicating that the central engine has stopped its activity and does not restart anymore after the prompt phase. (paper)

  19. The Effect of an Offset Polar Cap Dipolar Magnetic Field on the Modeling of the Vela Pulsar's Gamma-Ray Light Curves

    Barnard, M.; Venter, C.; Harding, A. K.

    2016-01-01

    We performed geometric pulsar light curve modeling using static, retarded vacuum, and offset polar cap (PC) dipole B-fields (the latter is characterized by a parameter epsilon), in conjunction with standard two-pole caustic (TPC) and outer gap (OG) emission geometries. The offset-PC dipole B-field mimics deviations from the static dipole (which corresponds to epsilon equals 0). In addition to constant-emissivity geometric models, we also considered a slot gap (SG) E-field associated with the offset-PC dipole B-field and found that its inclusion leads to qualitatively different light curves. Solving the particle transport equation shows that the particle energy only becomes large enough to yield significant curvature radiation at large altitudes above the stellar surface, given this relatively low E-field. Therefore, particles do not always attain the radiation-reaction limit. Our overall optimal light curve fit is for the retarded vacuum dipole field and OG model, at an inclination angle alpha equals 78 plus or minus 1 degree and observer angle zeta equals 69 plus 2 degrees or minus 1 degree. For this B-field, the TPC model is statistically disfavored compared to the OG model. For the static dipole field, neither model is significantly preferred. We found that smaller values of epsilon are favored for the offset-PC dipole field when assuming constant emissivity, and larger epsilon values favored for variable emissivity, but not significantly so. When multiplying the SG E-field by a factor of 100, we found improved light curve fits, with alpha and zeta being closer to best fits from independent studies, as well as curvature radiation reaction at lower altitudes.

  20. Testing the nature of the supermassive black hole candidate in SgrA* with light curves and images of hot spots

    Li, Zilong; Kong, Lingyao; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China)

    2014-06-01

    General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA*, the supermassive black hole candidate at the center of our Galaxy, and to open a new window to test the Kerr black hole hypothesis. In this paper, we compute light curves and images associated with compact emission regions (hot spots) orbiting around Kerr and non-Kerr black holes. We study how the analysis of the properties of the radiation emitted by a hot spot can be used to test the Kerr nature of SgrA*. We find that the sole observation of the hot spot light curve can at most constrain a combination of the black hole spin and of possible deviations from the Kerr solution. This happens because the same orbital frequency around a Kerr black hole can be found for a non-Kerr object with a different spin parameter. Second order corrections in the light curve due to the background geometry are typically too small to be identified. While the observation of the hot spot centroid track can potentially bound possible deviations from the Kerr solution, that is out of reach for the near future for the Very Large Telescope Interferometer instrument GRAVITY. The Kerr black hole hypothesis could really be tested in the case of the discovery of a radio pulsar in a compact orbit around SgrA*. Radio observations of such a pulsar would provide precise estimates of the mass and the spin of SgrA*, and the combination of these measurements (probing the weak field) with the hot spot light curve information (probing the strong field) may constrain/find possible deviations from the Kerr solution with quite good precision.

  1. NEAR-INFRARED LIGHT CURVES OF THE BROWN DWARF ECLIPSING BINARY 2MASS J05352184-0546085: CAN SPOTS EXPLAIN THE TEMPERATURE REVERSAL?

    Gomez Maqueo Chew, Yilen; Stassun, Keivan G.; Prsa, Andrej; Mathieu, Robert D.

    2009-01-01

    We present near-infrared JHK S light curves for the double-lined eclipsing binary system Two Micron All Sky Survey J05352184 - 0546085, in which both components have been shown to be brown dwarfs with an age of ∼1 Myr. We analyze these light curves together with the previously published I C -band light curve and radial velocities to provide refined measurements of the system's physical parameters. The component masses and radii are here determined with an accuracy of ∼6.5% and ∼1.5%, respectively. In addition, we confirm the previous surprising finding that the primary brown dwarf has a cooler effective temperature than its lower mass companion. Next, we perform a detailed study of the residual variations in the out-of-eclipse phases of the light curves to ascertain the properties of any inhomogeneities (e.g., spots) on the surfaces of the brown dwarfs. Our analysis reveals two low-amplitude (∼0.02 mag) periodic signals, one attributable to the rotation of the primary with a period of 3.293 ± 0.001 d and the other to the rotation of the secondary with a period of 14.05 ± 0.05 d. Both periods are consistent with the measured vsin i and radii. Finally, we explore the effects on the derived physical parameters of the system when spots are included in the modeling of the light curves. The observed low-amplitude rotational modulations are well fitted by cool spots covering a small fraction (∼<10%) of the brown dwarfs' surfaces. Such small spots negligibly affect the physical properties of the brown dwarfs, and thus by themselves cannot explain the primary's unexpectedly low surface temperature. To mimic the observed ∼200 K suppression of the primary's temperature, our model requires that the primary possesses a very large spot coverage fraction of ∼65%. These spots must in addition be symmetrically distributed on the primary's surface so as not to produce photometric variations larger than observed. Altogether, a spot configuration in which the primary

  2. A simulation of driven reconnection by a high precision MHD code

    Kusano, Kanya; Ouchi, Yasuo; Hayashi, Takaya; Horiuchi, Ritoku; Watanabe, Kunihiko; Sato, Tetsuya.

    1988-01-01

    A high precision MHD code, which has the fourth-order accuracy for both the spatial and time steps, is developed, and is applied to the simulation studies of two dimensional driven reconnection. It is confirm that the numerical dissipation of this new scheme is much less than that of two-step Lax-Wendroff scheme. The effect of the plasma compressibility on the reconnection dynamics is investigated by means of this high precision code. (author)

  3. Search for the signatures of a new-born black hole from the collapse of a supra-massive millisecond magnetar in short GRB light curves

    Zhang, Q.; Lei, W. H.; Zhang, B. B.; Chen, W.; Xiong, S. L.; Song, L. M.

    2018-03-01

    `Internal plateau' followed by a sharp decay is commonly seen in short gamma-ray burst (GRB) light curves. The plateau component is usually interpreted as the dipole emission from a supra-massive magnetar, and the sharp decay may imply the collapse of the magnetar to a black hole (BH). Fall-back accretion on to the new-born BH could produce long-lasting activities via the Blandford-Znajek (BZ) process. The magnetic flux accumulated near the BH would be confined by the accretion discs for a period of time. As the accretion rate decreases, the magnetic flux is strong enough to obstruct gas infall, leading to a magnetically arrested disc. Within this scenario, we show that the BZ process could produce two types of typical X-ray light curves: type I exhibits a long-lasting plateau, followed by a power-law (PL) decay with slopes ranging from 5/3 to 40/9; type II shows roughly a single PL decay with a slope of 5/3. The former requires low magnetic field strength, while the latter corresponds to relatively high values. We search for such signatures of the new-born BH from a sample of short GRBs with an internal plateau, and find two candidates: GRB 101219A and GRB 160821B, corresponding to type II and type I light curves, respectively. It is shown that our model can explain the data very well.

  4. Light-curve Modulation of Low-mass Stars in K2. I. Identification of 481 Fast Rotators in the Solar Neighborhood

    Saylor, Dicy; Lepine, Sebastien; Crossfield, Ian; Petigura, Erik A.

    2018-01-01

    The K2 mission is targeting large numbers of nearby (d 40 mas yr‑1, V < 20). Additionally, the mission is targeting low-mass, high proper motion stars associated with the local (d < 500 pc) Galactic halo population also selected from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 26,518 of these cool main-sequence stars. We used the auto-correlation function to search for fast rotators by identifying short-period photometric modulations in the K2 light curves. We identified 481 candidate fast rotators with rotation periods <4 days that show light-curve modulations consistent with starspots. Their kinematics show low average transverse velocities, suggesting that they are part of the young disk population. A subset (13) of the fast rotators is found among those targets with colors and kinematics consistent with the local Galactic halo population and may represent stars spun up by tidal interactions in close binary systems. We further demonstrate that the M dwarf fast rotators selected from the K2 light curves are significantly more likely to have UV excess and discuss the potential of the K2 mission to identify new nearby young GKM dwarfs on the basis of their fast rotation rates. Finally, we discuss the possible use of local halo stars as fiducial, non-variable sources in the Kepler fields.

  5. GRB 090313 AND THE ORIGIN OF OPTICAL PEAKS IN GAMMA-RAY BURST LIGHT CURVES: IMPLICATIONS FOR LORENTZ FACTORS AND RADIO FLARES

    Melandri, A.; Kobayashi, S.; Mundell, C. G.; Guidorzi, C.; Bersier, D.; Steele, I. A.; Smith, R. J.; De Ugarte Postigo, A.; Pooley, G.; Yoshida, M.; Castro-Tirado, A. J.; Gorosabel, J.; Kubanek, P.; Sota, A.; JelInek, M.; Gomboc, A.; Bremer, M.; Winters, J. M.; De Gregorio-Monsalvo, I.; GarcIa-Appadoo, D.

    2010-01-01

    We use a sample of 19 gamma-ray bursts (GRBs) that exhibit single-peaked optical light curves to test the standard fireball model by investigating the relationship between the time of the onset of the afterglow and the temporal rising index. Our sample includes GRBs and X-ray flashes for which we derive a wide range of initial Lorentz factors (40 e and show that values derived from the early time light-curve properties are consistent with published typical values derived from other afterglow studies. We produce expected radio light curves by predicting the temporal evolution of the expected radio emission from forward and reverse shock components, including synchrotron self-absorption effects at early time. Although a number of GRBs in this sample do not have published radio measurements, we demonstrate the effectiveness of this method in the case of Swift GRB 090313, for which millimetric and centimetric observations were available, and conclude that future detections of reverse-shock radio flares with new radio facilities such as the EVLA and ALMA will test the low-frequency model and provide constraints on magnetic models.

  6. Detection of a repeated transit signature in the light curve of the enigma star KIC 8462852: A possible 928-day period

    Kiefer, F.; Lecavelier des Étangs, A.; Vidal-Madjar, A.; Hébrard, G.; Bourrier, V.; Wilson, P. A.

    2017-12-01

    As revealed by its peculiar Kepler light curve, the enigmatic star KIC 8462852 undergoes short and deep flux dimmings at a priori unrelated epochs. This star presents nonetheless all other characteristics of a quiet 1 Gyr old F3V star. These dimmings resemble the absorption features expected for the transit of dust cometary tails. The exocomet scenario is therefore most commonly advocated. We reanalysed the Kepler data and extracted a new high-quality light curve to allow for the search of shallow signatures of single or a few exocomets. We discovered that among the 22 flux dimming events that we identified, two events present a striking similarity. These events occurred 928.25 days apart and lasted for 4.4 days with a drop in the star brightness by 1000 ppm. We show that the light curve of these events is well explained by the occultation of the star by a giant ring system or by the transit of a string of half a dozen exocomets with a typical dust production rate of 105-106 kg s-1. Assuming that these two similar events are related to the transit of the same object, we derive a period of 928.25 days. The following transit was expected in March 2017 but bad weather prohibited us from detecting it from ground-based spectroscopy. We predict that the next event will occur between 3-8 October 2019.

  7. The hamster clock phase-response curve from summerlike light:dark cycles and its role in daily and seasonal timekeeping.

    Alleva, John J; Alleva, Frederic R

    2002-11-01

    We address the subject of entrainment of the hamster clock by the day:night cycle in summer when the sun sets after 6 PM and rises before 6 AM (nights cycles were simulated by 6 light:dark (LD) cycles with D estrus and wheel running in hamsters. The onset of estrus was observed every 4 d in the same hamsters as a phase marker of their 24 h clock. On the day before an experimental estrus, preceded and followed by control onsets, a dark period was imposed to cover a putative 6 PM-6 AM light-sensitive period (LSP). This was scanned with a light pulse (and periodic 5 sec bell alarms) lasting 5-240 min. Shifts in onset of estrus on the next day were plotted vs. the end of the light pulse for PM times ("dusk") and its onset for AM times ("dawn"). The resulting phase shifts from the six SLDs were similar, permitting their combination into a single phase-response curve (PRC) of 1605 shifts. This SLD composite PRC rose at 10:15 PM, peaked at 2 AM (81 min advanced shift), fell linearly to 5:55 AM, and then abruptly to normal at 6 AM (no shift). Peak shift was unaffected by light pulse duration or intensity, or hamster age. The SLD composite PRC lacked the 6 PM-9 PM curve of delayed shifts present in reported PRCs from LD 12 h:12 h and DD. However, a two-pulse experiment showed that all light from 6 PM to L-off was needed to block (balance) the advancing action of a 5 min morning light pulse, thereby maintaining entrainment. A working hypothesis to explain daily entrainment and seasonal fertility in the golden hamster is illustrated. A nomenclature for labeling the phases of the hamster clock (circadian time) is proposed.

  8. GENERATION OF HIGH RESOLUTION AND HIGH PRECISION ORTHORECTIFIED ROAD IMAGERY FROM MOBILE MAPPING SYSTEM

    M. Sakamoto

    2012-07-01

    Full Text Available In this paper, a novel technique to generate a high resolution and high precision Orthorectified Road Imagery (ORI by using spatial information acquired from a Mobile Mapping System (MMS is introduced. The MMS was equipped with multiple sensors such as GPS, IMU, odometer, 2-6 digital cameras and 2-4 laser scanners. In this study, a Triangulated Irregular Network (TIN based approach, similar to general aerial photogrammetry, was adopted to build a terrain model in order to generate ORI with high resolution and high geometric precision. Compared to aerial photogrammetry, there are several issues that are needed to be addressed. ORI is generated by merging multiple time sequence images of a short section. Hence, the influence of occlusion due to stationary objects, such as telephone poles, trees, footbridges, or moving objects, such as vehicles, pedestrians are very significant. Moreover, influences of light falloff at the edges of cameras, tone adjustment among images captured from different cameras or a round trip data acquisition of the same path, and time lag between image exposure and laser point acquisition also need to be addressed properly. The proposed method was applied to generate ORI with 1 cm resolution, from the actual MMS data sets. The ORI generated by the proposed technique was more clear, occlusion free and with higher resolution compared to the conventional orthorectified coloured point cloud imagery. Moreover, the visual interpretation of road features from the ORI was much easier. In addition, the experimental results also validated the effectiveness of proposed radiometric corrections. In occluded regions, the ORI was compensated by using other images captured from different angles. The validity of the image masking process, in the occluded regions, was also ascertained.

  9. Technical accuracy of a neuronavigation system measured with a high-precision mechanical micromanipulator.

    Kaus, M; Steinmeier, R; Sporer, T; Ganslandt, O; Fahlbusch, R

    1997-12-01

    This study was designed to determine and evaluate the different system-inherent sources of erroneous target localization of a light-emitting diode (LED)-based neuronavigation system (StealthStation, Stealth Technologies, Boulder, CO). The localization accuracy was estimated by applying a high-precision mechanical micromanipulator to move and exactly locate (+/- 0.1 micron) the pointer at multiple positions in the physical three-dimensional space. The localization error was evaluated by calculating the spatial distance between the (known) LED positions and the LED coordinates measured by the neuronavigator. The results are based on a study of approximately 280,000 independent coordinate measurements. The maximum localization error detected was 0.55 +/- 0.29 mm, with the z direction (distance to the camera array) being the most erroneous coordinate. Minimum localization error was found at a distance of 1400 mm from the central camera (optimal measurement position). Additional error due to 1) mechanical vibrations of the camera tripod (+/- 0.15 mm) and the reference frame (+/- 0.08 mm) and 2) extrapolation of the pointer tip position from the LED coordinates of at least +/- 0.12 mm were detected, leading to a total technical error of 0.55 +/- 0.64 mm. Based on this technical accuracy analysis, a set of handling recommendations is proposed, leading to an improved localization accuracy. The localization error could be reduced by 0.3 +/- 0.15 mm by correct camera positioning (1400 mm distance) plus 0.15 mm by vibration-eliminating fixation of the camera. Correct handling of the probe during the operation may improve the accuracy by up to 0.1 mm.

  10. A near infrared laser frequency comb for high precision Doppler planet surveys

    Bally J.

    2011-07-01

    Full Text Available Perhaps the most exciting area of astronomical research today is the study of exoplanets and exoplanetary systems, engaging the imagination not just of the astronomical community, but of the general population. Astronomical instrumentation has matured to the level where it is possible to detect terrestrial planets orbiting distant stars via radial velocity (RV measurements, with the most stable visible light spectrographs reporting RV results the order of 1 m/s. This, however, is an order of magnitude away from the precision needed to detect an Earth analog orbiting a star such as our sun, the Holy Grail of these efforts. By performing these observations in near infrared (NIR there is the potential to simplify the search for distant terrestrial planets by studying cooler, less massive, much more numerous class M stars, with a tighter habitable zone and correspondingly larger RV signal. This NIR advantage is undone by the lack of a suitable high precision, high stability wavelength standard, limiting NIR RV measurements to tens or hundreds of m/s [1, 2]. With the improved spectroscopic precision provided by a laser frequency comb based wavelength reference producing a set of bright, densely and uniformly spaced lines, it will be possible to achieve up to two orders of magnitude improvement in RV precision, limited only by the precision and sensitivity of existing spectrographs, enabling the observation of Earth analogs through RV measurements. We discuss the laser frequency comb as an astronomical wavelength reference, and describe progress towards a near infrared laser frequency comb at the National Institute of Standards and Technology and at the University of Colorado where we are operating a laser frequency comb suitable for use with a high resolution H band astronomical spectrograph.

  11. CHANGING PHASES OF ALIEN WORLDS: PROBING ATMOSPHERES OF KEPLER PLANETS WITH HIGH-PRECISION PHOTOMETRY

    Esteves, Lisa J.; Mooij, Ernst J. W. De [Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Jayawardhana, Ray, E-mail: esteves@astro.utoronto.ca, E-mail: demooij@astro.utoronto.ca, E-mail: rayjay@yorku.ca [Physics and Astronomy, York University, Toronto, Ontario L3T 3R1 (Canada)

    2015-05-10

    We present a comprehensive analysis of planetary phase variations, including possible planetary light offsets, using eighteen quarters of data from the Kepler space telescope. Our analysis found fourteen systems with significant detections in each of the phase curve components: planet’s phase function, secondary eclipse, Doppler boosting, and ellipsoidal variations. We model the full phase curve simultaneously, including primary and secondary transits, and derive albedos, day- and night-side temperatures and planet masses. Most planets manifest low optical geometric albedos (< 0.25), with the exception of Kepler-10b, Kepler-91b, and KOI-13b. We find that KOI-13b, with a small eccentricity of 0.0006 ± 0.0001, is the only planet for which an eccentric orbit is favored. We detect a third harmonic for HAT-P-7b for the first time, and confirm the third harmonic for KOI-13b reported in Esteves et al.: both could be due to their spin–orbit misalignments. For six planets, we report a planetary brightness peak offset from the substellar point: of those, the hottest two (Kepler-76b and HAT-P-7b) exhibit pre-eclipse shifts or on the evening-side, while the cooler four (Kepler-7b, Kepler-8b, Kepler-12b, and Kepler-41b) peak post-eclipse or on the morning-side. Our findings dramatically increase the number of Kepler planets with detected planetary light offsets, and provide the first evidence in the Kepler data for a correlation between the peak offset direction and the planet’s temperature. Such a correlation could arise if thermal emission dominates light from hotter planets that harbor hot spots shifted toward the evening-side, as theoretically predicted, while reflected light dominates cooler planets with clouds on the planet’s morning-side.

  12. Limb darkening laws for two exoplanet host stars derived from 3D stellar model atmospheres. Comparison with 1D models and HST light curve observations

    Hayek, W.; Sing, D.; Pont, F.; Asplund, M.

    2012-03-01

    We compare limb darkening laws derived from 3D hydrodynamical model atmospheres and 1D hydrostatic MARCS models for the host stars of two well-studied transiting exoplanet systems, the late-type dwarfs HD 209458 and HD 189733. The surface brightness distribution of the stellar disks is calculated for a wide spectral range using 3D LTE spectrum formation and opacity sampling⋆. We test our theoretical predictions using least-squares fits of model light curves to wavelength-integrated primary eclipses that were observed with the Hubble Space Telescope (HST). The limb darkening law derived from the 3D model of HD 209458 in the spectral region between 2900 Å and 5700 Å produces significantly better fits to the HST data, removing systematic residuals that were previously observed for model light curves based on 1D limb darkening predictions. This difference arises mainly from the shallower mean temperature structure of the 3D model, which is a consequence of the explicit simulation of stellar surface granulation where 1D models need to rely on simplified recipes. In the case of HD 189733, the model atmospheres produce practically equivalent limb darkening curves between 2900 Å and 5700 Å, partly due to obstruction by spectral lines, and the data are not sufficient to distinguish between the light curves. We also analyze HST observations between 5350 Å and 10 500 Å for this star; the 3D model leads to a better fit compared to 1D limb darkening predictions. The significant improvement of fit quality for the HD 209458 system demonstrates the higher degree of realism of 3D hydrodynamical models and the importance of surface granulation for the formation of the atmospheric radiation field of late-type stars. This result agrees well with recent investigations of limb darkening in the solar continuum and other observational tests of the 3D models. The case of HD 189733 is no contradiction as the model light curves are less sensitive to the temperature stratification of

  13. An Ultra-low Frequency Modal Testing Suspension System for High Precision Air Pressure Control

    Qiaoling YUAN

    2014-05-01

    Full Text Available As a resolution for air pressure control challenges in ultra-low frequency modal testing suspension systems, an incremental PID control algorithm with dead band is applied to achieve high-precision pressure control. We also develop a set of independent hardware and software systems for high-precision pressure control solutions. Taking control system versatility, scalability, reliability, and other aspects into considerations, a two-level communication employing Ethernet and CAN bus, is adopted to complete such tasks as data exchange between the IPC, the main board and the control board ,and the pressure control. Furthermore, we build a single set of ultra-low frequency modal testing suspension system and complete pressure control experiments, which achieve the desired results and thus confirm that the high-precision pressure control subsystem is reasonable and reliable.

  14. High-Precision Registration of Point Clouds Based on Sphere Feature Constraints

    Junhui Huang

    2016-12-01

    Full Text Available Point cloud registration is a key process in multi-view 3D measurements. Its precision affects the measurement precision directly. However, in the case of the point clouds with non-overlapping areas or curvature invariant surface, it is difficult to achieve a high precision. A high precision registration method based on sphere feature constraint is presented to overcome the difficulty in the paper. Some known sphere features with constraints are used to construct virtual overlapping areas. The virtual overlapping areas provide more accurate corresponding point pairs and reduce the influence of noise. Then the transformation parameters between the registered point clouds are solved by an optimization method with weight function. In that case, the impact of large noise in point clouds can be reduced and a high precision registration is achieved. Simulation and experiments validate the proposed method.

  15. A High Precision Laser-Based Autofocus Method Using Biased Image Plane for Microscopy

    Chao-Chen Gu

    2018-01-01

    Full Text Available This study designs and accomplishes a high precision and robust laser-based autofocusing system, in which a biased image plane is applied. In accordance to the designed optics, a cluster-based circle fitting algorithm is proposed to calculate the radius of the detecting spot from the reflected laser beam as an essential factor to obtain the defocus value. The experiment conduct on the experiment device achieved novel performance of high precision and robustness. Furthermore, the low demand of assembly accuracy makes the proposed method a low-cost and realizable solution for autofocusing technique.

  16. Machine vision for high-precision volume measurement applied to levitated containerless material processing

    Bradshaw, R.C.; Schmidt, D.P.; Rogers, J.R.; Kelton, K.F.; Hyers, R.W.

    2005-01-01

    By combining the best practices in optical dilatometry with numerical methods, a high-speed and high-precision technique has been developed to measure the volume of levitated, containerlessly processed samples with subpixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermophysical properties. Levitation is a common technique used to isolate a sample as it is being processed. Noncontact optical measurement of thermophysical properties is very important as traditional measuring methods cannot be used. Modern, digitally recorded images require advanced numerical routines to recover the subpixel locations of sample edges and, in turn, produce high-precision measurements

  17. Design of a self-calibration high precision micro-angle deformation optical monitoring scheme

    Gu, Yingying; Wang, Li; Guo, Shaogang; Wu, Yun; Liu, Da

    2018-03-01

    In order to meet the requirement of high precision and micro-angle measurement on orbit, a self-calibrated optical non-contact real-time monitoring device is designed. Within three meters, the micro-angle variable of target relative to measuring basis can be measured in real-time. The range of angle measurement is +/-50'', the angle measurement accuracy is less than 2''. The equipment can realize high precision real-time monitoring the micro-angle deformation, which caused by high strength vibration and shock of rock launching, sun radiation and heat conduction on orbit and so on.

  18. High precision NC lathe feeding system rigid-flexible coupling model reduction technology

    Xuan, He; Hua, Qingsong; Cheng, Lianjun; Zhang, Hongxin; Zhao, Qinghai; Mao, Xinkai

    2017-08-01

    This paper proposes the use of dynamic substructure method of reduction of order to achieve effective reduction of feed system for high precision NC lathe feeding system rigid-flexible coupling model, namely the use of ADAMS to establish the rigid flexible coupling simulation model of high precision NC lathe, and then the vibration simulation of the period by using the FD 3D damper is very effective for feed system of bolt connection reduction of multi degree of freedom model. The vibration simulation calculation is more accurate, more quickly.

  19. Column Store for GWAC: A High-cadence, High-density, Large-scale Astronomical Light Curve Pipeline and Distributed Shared-nothing Database

    Wan, Meng; Wu, Chao; Wang, Jing; Qiu, Yulei; Xin, Liping; Mullender, Sjoerd; Mühleisen, Hannes; Scheers, Bart; Zhang, Ying; Nes, Niels; Kersten, Martin; Huang, Yongpan; Deng, Jinsong; Wei, Jianyan

    2016-11-01

    The ground-based wide-angle camera array (GWAC), a part of the SVOM space mission, will search for various types of optical transients by continuously imaging a field of view (FOV) of 5000 degrees2 every 15 s. Each exposure consists of 36 × 4k × 4k pixels, typically resulting in 36 × ˜175,600 extracted sources. For a modern time-domain astronomy project like GWAC, which produces massive amounts of data with a high cadence, it is challenging to search for short timescale transients in both real-time and archived data, and to build long-term light curves for variable sources. Here, we develop a high-cadence, high-density light curve pipeline (HCHDLP) to process the GWAC data in real-time, and design a distributed shared-nothing database to manage the massive amount of archived data which will be used to generate a source catalog with more than 100 billion records during 10 years of operation. First, we develop HCHDLP based on the column-store DBMS of MonetDB, taking advantage of MonetDB’s high performance when applied to massive data processing. To realize the real-time functionality of HCHDLP, we optimize the pipeline in its source association function, including both time and space complexity from outside the database (SQL semantic) and inside (RANGE-JOIN implementation), as well as in its strategy of building complex light curves. The optimized source association function is accelerated by three orders of magnitude. Second, we build a distributed database using a two-level time partitioning strategy via the MERGE TABLE and REMOTE TABLE technology of MonetDB. Intensive tests validate that our database architecture is able to achieve both linear scalability in response time and concurrent access by multiple users. In summary, our studies provide guidance for a solution to GWAC in real-time data processing and management of massive data.

  20. Multi-color light curves of type Ia supernovae on the color-magnitude diagram: A novel step toward more precise distance and extinction estimates

    Wang, Lifan; Goldhaber, Gerson; Aldering, Greg; Perlmutter, Saul

    2003-01-01

    We show empirically that fits to the color-magnitude relation of Type Ia supernovae after optical maximum can provide accurate relative extragalactic distances. We report the discovery of an empirical color relation for Type Ia light curves: During much of the first month past maximum, the magnitudes of Type Ia supernovae defined at a given value of color index have a very small magnitude dispersion; moreover, during this period the relation between B magnitude and B-V color (or B-Ror B-I color) is strikingly linear, to the accuracy of existing well-measured data. These linear relations can provide robust distance estimates, in particular, by using the magnitudes when the supernova reaches a given color. After correction for light curve stretch factor or decline rate, the dispersion of the magnitudes taken at the intercept of the linear color-magnitude relation are found to be around 0 m .08 for the sub-sample of supernovae with (B max - V max ) (le) 0 m 0.5, and around 0 m .11 for the sub-sample with (B max - V max ) (le) 0 m .2. This small dispersion is consistent with being mostly due to observational errors. The method presented here and the conventional light curve fitting methods can be combined to further improve statistical dispersions of distance estimates. It can be combined with the magnitude at maximum to deduce dust extinction. The slopes of the color-magnitude relation may also be used to identify intrinsically different SN Ia systems. The method provides a tool that is fundamental to using SN Ia to estimate cosmological parameters such as the Hubble constant and the mass and dark energy content of the universe

  1. Determination of the orientation of the white dwarf's magnetic axis from X-ray orbital light curves

    Andronov, I.L.

    1986-01-01

    The directional pattern of soft X-ray radiation produced in a ''polar cap'' on the white dwarf's surface is calculated taking into account the absorption in the axially symmetrical accretion column, homogeneous along its height. An algorithm for the determination of orientation of the magnetic axis of a compact star from orbital curves of soft X-ray flux, is suggested. The values of the orbital inclination i (51 deg <=i<64 deg) and the angle between the rotational and magnetic axes σ (30 deg <=σ<=34 deg) were calculated for the polar AM Herculis for different values of model parameters

  2. Using High-Precision Specific Gravity Measurements to Study Minerals in Undergraduate Geoscience Courses

    Brandriss, Mark E.

    2010-01-01

    This article describes ways to incorporate high-precision measurements of the specific gravities of minerals into undergraduate courses in mineralogy and physical geology. Most traditional undergraduate laboratory methods of measuring specific gravity are suitable only for unusually large samples, which severely limits their usefulness for student…

  3. MiniDSS: a low-power and high-precision miniaturized digital sun sensor

    Boer, B.M. de; Durkut, M.; Laan, E.; Hakkesteegt, H.; Theuwissen, A.; Xie, N.; Leijtens, J.L.; Urquijo, E.; Bruins, P.

    2012-01-01

    A high-precision and low-power miniaturized digital sun sensor has been developed at TNO. The single-chip sun sensor comprises an application specific integrated circuit (ASIC) on which an active pixel sensor (APS), read-out and processing circuitry as well as communication circuitry are combined.

  4. Classification of LIDAR Data for Generating a High-Precision Roadway Map

    Jeong, J.; Lee, I.

    2016-06-01

    Generating of a highly precise map grows up with development of autonomous driving vehicles. The highly precise map includes a precision of centimetres level unlike an existing commercial map with the precision of meters level. It is important to understand road environments and make a decision for autonomous driving since a robust localization is one of the critical challenges for the autonomous driving car. The one of source data is from a Lidar because it provides highly dense point cloud data with three dimensional position, intensities and ranges from the sensor to target. In this paper, we focus on how to segment point cloud data from a Lidar on a vehicle and classify objects on the road for the highly precise map. In particular, we propose the combination with a feature descriptor and a classification algorithm in machine learning. Objects can be distinguish by geometrical features based on a surface normal of each point. To achieve correct classification using limited point cloud data sets, a Support Vector Machine algorithm in machine learning are used. Final step is to evaluate accuracies of obtained results by comparing them to reference data The results show sufficient accuracy and it will be utilized to generate a highly precise road map.

  5. CLASSIFICATION OF LIDAR DATA FOR GENERATING A HIGH-PRECISION ROADWAY MAP

    J. Jeong

    2016-06-01

    Full Text Available Generating of a highly precise map grows up with development of autonomous driving vehicles. The highly precise map includes a precision of centimetres level unlike an existing commercial map with the precision of meters level. It is important to understand road environments and make a decision for autonomous driving since a robust localization is one of the critical challenges for the autonomous driving car. The one of source data is from a Lidar because it provides highly dense point cloud data with three dimensional position, intensities and ranges from the sensor to target. In this paper, we focus on how to segment point cloud data from a Lidar on a vehicle and classify objects on the road for the highly precise map. In particular, we propose the combination with a feature descriptor and a classification algorithm in machine learning. Objects can be distinguish by geometrical features based on a surface normal of each point. To achieve correct classification using limited point cloud data sets, a Support Vector Machine algorithm in machine learning are used. Final step is to evaluate accuracies of obtained results by comparing them to reference data The results show sufficient accuracy and it will be utilized to generate a highly precise road map.

  6. High-precision photometry by telescope defocusing - I. The transiting planetary system WASP-5

    Southworth, J.; Hinse, T. C.; Jørgensen, U. G.

    2009-01-01

    We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54-m telescope at European Southern Obseratory La Silla. In order to minimize both random and flat-fielding errors, we defocused the telescope so its point spread...

  7. High precision locating control system based on VCM for Talbot lithography

    Yao, Jingwei; Zhao, Lixin; Deng, Qian; Hu, Song

    2016-10-01

    Aiming at the high precision and efficiency requirements of Z-direction locating in Talbot lithography, a control system based on Voice Coil Motor (VCM) was designed. In this paper, we built a math model of VCM and its moving characteristic was analyzed. A double-closed loop control strategy including position loop and current loop were accomplished. The current loop was implemented by driver, in order to achieve the rapid follow of the system current. The position loop was completed by the digital signal processor (DSP) and the position feedback was achieved by high precision linear scales. Feed forward control and position feedback Proportion Integration Differentiation (PID) control were applied in order to compensate for dynamic lag and improve the response speed of the system. And the high precision and efficiency of the system were verified by simulation and experiments. The results demonstrated that the performance of Z-direction gantry was obviously improved, having high precision, quick responses, strong real-time and easily to expend for higher precision.

  8. Self-tuning in master-slave synchronization of high-precision stage systems

    Heertjes, M.F.; Temizer, B.; Schneiders, M.G.E.

    2013-01-01

    For synchronization of high-precision stage systems, in particular the synchronization between a wafer and a reticle stage system of a wafer scanner, a master–slave controller design is presented. The design consists of a synchronization controller based on FIR filters and a data-driven self-tuning

  9. Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition

    Pribil, M.J.; Wanty, R.B.; Ridley, W.I.; Borrok, D.M.

    2010-01-01

    An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations in acid mine drainage (AMD) can range from 100??g/L to greater than 50mg/L with sulfur species concentrations reaching greater than 1000mg/L. Routine separation of Cu, Fe and Zn from AMD, Cu-sulfide minerals and other geological matrices usually incorporates single anion exchange resin column chromatography for metal separation. During chromatographic separation, variable breakthrough of SO42- during anion exchange resin column chromatography into the Cu fractions was observed as a function of the initial sulfur to Cu ratio, column properties, and the sample matrix. SO42- present in the Cu fraction can form a polyatomic 32S-14N-16O-1H species causing a direct mass interference with 63Cu and producing artificially light ??65Cu values. Here we report the extent of the mass interference caused by SO42- breakthrough when measuring ??65Cu on natural samples and NIST SRM 976 Cu isotope spiked with SO42- after both single anion column chromatography and double anion column chromatography. A set of five 100??g/L Cu SRM 976 samples spiked with 500mg/L SO42- resulted in an average ??65Cu of -3.50?????5.42??? following single anion column separation with variable SO42- breakthrough but an average concentration of 770??g/L. Following double anion column separation, the average SO42-concentration of 13??g/L resulted in better precision and accuracy for the measured ??65Cu value of 0.01?????0.02??? relative to the expected 0??? for SRM 976. We conclude that attention to SO42- breakthrough on sulfur-rich samples is necessary for accurate and precise measurements of ??65Cu and may require

  10. BEER ANALYSIS OF KEPLER AND CoRoT LIGHT CURVES. IV. DISCOVERY OF FOUR NEW LOW-MASS WHITE DWARF COMPANIONS IN THE KEPLER DATA

    Faigler, S.; Kull, I.; Mazeh, T.; Kiefer, F. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Latham, D. W. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bloemen, S. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. BOX 9010, NL-6500 GL Nijmegen (Netherlands)

    2015-12-10

    We report the discovery of four short-period eclipsing systems in the Kepler light curves, consisting of an A-star primary and a low-mass white dwarf (WD) secondary (dA+WD)—KIC 4169521, KOI-3818, KIC 2851474, and KIC 9285587. The systems show BEaming, Ellipsoidal and Reflection (BEER) phase modulations together with primary and secondary eclipses. These add to the 6 Kepler and 18 WASP short-period eclipsing dA+WD binaries that were previously known. The light curves, together with follow-up spectroscopic observations, allow us to derive the masses, radii, and effective temperatures of the two components of the four systems. The orbital periods, of 1.17–3.82 days, and WD masses, of 0.19–0.22 M{sub ⊙}, are similar to those of the previously known systems. The WD radii of KOI-3818, KIC 2851474, and KIC 9285587 are 0.026, 0.035, and 0.026 R{sub ⊙}, respectively, the smallest WD radii derived so far for short-period eclipsing dA+WD binaries. These three binaries extend the previously known population to older systems with cooler and smaller WD secondaries. KOI-3818 displays evidence for a fast-rotating primary and a minute but significant eccentricity, ∼1.5 × 10{sup −3}. These features are probably the outcome of the mass-transfer process.

  11. A Correlation Between the Intrinsic Brightness and Average Decay Rate of Gamma-Ray Burst X-Ray Afterglow Light Curves

    Racusin, J. L.; Oates, S. R.; De Pasquale, M.; Kocevski, D.

    2016-01-01

    We present a correlation between the average temporal decay (alpha X,avg, greater than 200 s) and early-time luminosity (LX,200 s) of X-ray afterglows of gamma-ray bursts as observed by the Swift X-ray Telescope. Both quantities are measured relative to a rest-frame time of 200 s after the gamma-ray trigger. The luminosity â€" average decay correlation does not depend on specific temporal behavior and contains one scale-independent quantity minimizing the role of selection effects. This is a complementary correlation to that discovered by Oates et al. in the optical light curves observed by the Swift Ultraviolet Optical Telescope. The correlation indicates that, on average, more luminous X-ray afterglows decay faster than less luminous ones, indicating some relative mechanism for energy dissipation. The X-ray and optical correlations are entirely consistent once corrections are applied and contamination is removed. We explore the possible biases introduced by different light-curve morphologies and observational selection effects, and how either geometrical effects or intrinsic properties of the central engine and jet could explain the observed correlation.

  12. Multi-color light curves of type Ia supernovae on thecolor-magnitude diagram: A novel step toward more precise distance andextinction estimates

    Wang, Lifan; Goldhaber, Gerson; Aldering, Greg; Perlmutter, Saul

    2003-01-31

    We show empirically that fits to the color-magnituderelation of Type Ia supernovae after optical maximum can provide accuraterelative extragalactic distances. We report the discovery of an empiricalcolor relation for Type Ia light curves: During much of the first monthpast maximum, the magnitudes of Type Ia supernovae defined at a givenvalue of color index have a very small magnitude dispersion; moreover,during this period the relation between B magnitude and B-V color (or B-Ror B-I color) is strikingly linear, to the accuracy of existingwell-measured data. These linear relations can provide robust distanceestimates, in particular, by using the magnitudes when the supernovareaches a given color. After correction for light curve stretch factor ordecline rate, the dispersion of the magnitudes taken at the intercept ofthe linear color-magnitude relation are found to be around 0^m .08 forthe sub-sample of supernovae with (B_max - V_max) ?= 0^m 0.5, andaround 0^m.11 for the sub-sample with (B_max - V_max) ?= 0^m .2.This small dispersion is consistent with being mostly due toobservational errors. The method presented here and the conventionallight curve fitting methods can be combined to further improvestatistical dispersions of distance estimates. It can be combined withthe magnitude at maximum to deduce dust extinction. Theslopes of thecolor-magnitude relation may also be used to identify intrinsicallydifferent SN Ia systems. The method provides a tool that is fundamentalto using SN Ia to estimate cosmological parameters such as the Hubbleconstant and the mass and dark energy content of theuniverse.

  13. FY 1998 annual summary report on 6-axis, high-precision non-rotating machining systems (first year); 1998 nendo 6 jiku koseido heru kako system no kaihatsu seika hokokusho. Daiichinendo

    NONE

    1999-03-01

    This R and D program is aimed at development of high-precision systems, based on non-rotating machining, in order to improve precision of machining of curved surfaces, e.g., mold, and members of complex shapes, e.g., those for aircraft. For non-rotating machining of curved surfaces, it is necessary to continuously control attitude and sending speed of the tool, and hence to simultaneously control 6 axes of a high-speed, high-precision tool machine. New techniques, e.g., high-precision non-rotating machining, 6-axis CAM/CAE systems and high-speed, high-precision NC systems, are being developed, in order to realize the above objectives. The total systems combining these techniques are also being developed. The 6-axis, high-precision, non-rotating tool machine will be made on a trial basis, to demonstrate its practicality. The major FY 1998 results are development of a non-rotating machining tool for deep grooves (under the theme of machining techniques), development of software for cutter path generation for 6-axis non-rotating machining to confirm its validity by the tests with a commercial machine (CAD/CAM), and modification of NC for early-stage cutting tests (NC). (NEDO)

  14. Correlation between SiO v = 3 J = 1 → 0 maser excitation and the light curve of a long-period variable star

    Oyadomari, Miyako; Imai, Hiroshi; Nagayama, Takumi; Oyama, Tomoaki; Matsumoto, Naoko; Nakashima, Jun-ichi; Cho, Se-Hyung

    2018-03-01

    In order to understand the excitation mechanisms of silicon monoxide (SiO) masers around long-period variables (LPVs), we have investigated distributions of the SiO v = 2 and v = 3 J = 1 → 0 masers around 12 LPVs by very long baseline interferometry (VLBI) observations with the VLBI Exploration of Radio Astrometry (VERA) and the Nobeyama 45 m telescopes. VLBI fringes of the v = 3 maser emission were detected for five LPVs. The composite maps of the v = 2 and v = 3 masers were made for T Cep, W Hya, WX Psc, and R Leo using the spectral line phase-referencing technique. The v = 2 maser spots were distributed in a ring-like form around the central stars, while it is difficult to recognize any specific morphology in the v = 3 maser distributions due to the small number of v = 3 spots detected. However in T Cep, we find that the distribution of the v = 3 maser spots correlates well with the v = 2 masers within a few milliarcseconds (0.2-0.3 au) in position and 1 km s-1 in line-of-sight velocity at the light curve phase of ϕ = 0.28 (ϕ = 0.0 and 1.0 correspond to the visible light maxima). This correlation implies that the mechanism of line-overlapping between the mid-infrared lines of H2O and SiO molecules works in T Cep at ϕ = 0.28. We discuss the possibility that the line-overlapping may work at the limited duration from the maximum to the minimum of the stellar light curve.

  15. SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-01-01

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρ ext ∝r –k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ 0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ –1 0 . For larger k values, however, the lateral expansion is faster at early times (when Γ > θ –1 0 ) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θ obs ≤ θ 0 ) than by the slope of the external density profile (for 0 ≤ k ≤ 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet

  16. Simulations of Gamma-Ray Burst Jets in a Stratified External Medium: Dynamics, Afterglow Light Curves, Jet Breaks, and Radio Calorimetry

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-05-01

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with ρextvpropr -k for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle θ0 = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor Γ drops below θ-1 0. For larger k values, however, the lateral expansion is faster at early times (when Γ > θ-1 0) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for θobs <= θ0) than by the slope of the external density profile (for 0 <= k <= 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results in a clear bump-like feature in the light curve. However, for larger k values the jet decelerates more

  17. SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

    De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)

    2012-05-20

    The dynamics of gamma-ray burst (GRB) jets during the afterglow phase is most reliably and accurately modeled using hydrodynamic simulations. All published simulations so far, however, have considered only a uniform external medium, while a stratified external medium is expected around long duration GRB progenitors. Here, we present simulations of the dynamics of GRB jets and the resulting afterglow emission for both uniform and stratified external media with {rho}{sub ext}{proportional_to}r{sup -k} for k = 0, 1, 2. The simulations are performed in two dimensions using the special relativistic version of the Mezcal code. Common to all calculations is the initiation of the GRB jet as a conical wedge of half-opening angle {theta}{sub 0} = 0.2 whose radial profile is taken from the self-similar Blandford-McKee solution. The dynamics for stratified external media (k = 1, 2) are broadly similar to those derived for expansion into a uniform external medium (k = 0). The jet half-opening angle is observed to start increasing logarithmically with time (or radius) once the Lorentz factor {Gamma} drops below {theta}{sup -1}{sub 0}. For larger k values, however, the lateral expansion is faster at early times (when {Gamma} > {theta}{sup -1}{sub 0}) and slower at late times with the jet expansion becoming Newtonian and slowly approaching spherical symmetry over progressively longer timescales. We find that, contrary to analytic expectations, there is a reasonably sharp jet break in the light curve for k = 2 (a wind-like external medium), although the shape of the break is affected more by the viewing angle (for {theta}{sub obs} {<=} {theta}{sub 0}) than by the slope of the external density profile (for 0 {<=} k {<=} 2). Steeper density profiles (i.e., increasing k values) are found to produce more gradual jet breaks while larger viewing angles cause smoother and later appearing jet breaks. The counterjet becomes visible as it becomes sub-relativistic, and for k = 0 this results

  18. High Precision Measurement of the differential W and Z boson cross-sections

    Gasnikova, Ksenia; The ATLAS collaboration

    2017-01-01

    Measurements of the Drell-Yan production of W and Z/gamma bosons at the LHC provide a benchmark of our understanding of perturbative QCD and probe the proton structure in a unique way. The ATLAS collaboration has performed new high precision measurements at center-of-mass energies of 7. The measurements are performed for W+, W- and Z/gamma bosons integrated and as a function of the boson or lepton rapidity and the Z/gamma* mass. Unprecedented precision is reached and strong constraints on Parton Distribution functions, in particular the strange density are found. Z cross sections are also measured at a center-of-mass energies of 8TeV and 13TeV, and cross-section ratios to the top-quark pair production have been derived. This ratio measurement leads to a cancellation of several systematic effects and allows therefore for a high precision comparison to the theory predictions.

  19. MRPC-PET: A new technique for high precision time and position measurements

    Doroud, K.; Hatzifotiadou, D.; Li, S.; Williams, M.C.S.; Zichichi, A.; Zuyeuski, R.

    2011-01-01

    The purpose of this paper is to consider a new technology for medical diagnosis: the MRPC-PET. This technology allows excellent time resolution together with 2-D position information thus providing a fundamental step in this field. The principle of this method is based on the Multigap Resistive Plate Chamber (MRPC) capable of high precision time measurements. We have previously found that the route to precise timing is differential readout (this requires matching anode and cathode strips); thus crossed strip readout schemes traditionally used for 2-D readout cannot be exploited. In this paper we consider the time difference from the two ends of the strip to provide a high precision measurement along the strip; the average time gives precise timing. The MRPC-PET thus provides a basic step in the field of medical technology: excellent time resolution together with 2-D position measurement.

  20. High-Precision Half-Life Measurement for the Superallowed β+ Emitter Alm26

    Finlay, P.; Ettenauer, S.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.

    2011-01-01

    A high-precision half-life measurement for the superallowed β+ emitter Alm26 was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1/2=6346.54±0.46stat±0.60systms, consistent with, but 2.5 times more precise than, the previous world average. The Alm26 half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed β decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for Alm26, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi β-decay studies used to test the conserved vector current hypothesis and determine the Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

  1. A Study of Particle Beam Spin Dynamics for High Precision Experiments

    Fiedler, Andrew J. [Northern Illinois Univ., DeKalb, IL (United States)

    2017-05-01

    In the search for physics beyond the Standard Model, high precision experiments to measure fundamental properties of particles are an important frontier. One group of such measurements involves magnetic dipole moment (MDM) values as well as searching for an electric dipole moment (EDM), both of which could provide insights about how particles interact with their environment at the quantum level and if there are undiscovered new particles. For these types of high precision experiments, minimizing statistical uncertainties in the measurements plays a critical role. \\\\ \\indent This work leverages computer simulations to quantify the effects of statistical uncertainty for experiments investigating spin dynamics. In it, analysis of beam properties and lattice design effects on the polarization of the beam is performed. As a case study, the beam lines that will provide polarized muon beams to the Fermilab Muon \\emph{g}-2 experiment are analyzed to determine the effects of correlations between the phase space variables and the overall polarization of the muon beam.

  2. Laser-generated ultrasound for high-precision cutting of tissue-mimicking gels (Conference Presentation)

    Lee, Taehwa; Luo, Wei; Li, Qiaochu; Guo, L. Jay

    2017-03-01

    Laser-generated focused ultrasound has shown great promise in precisely treating cells and tissues by producing controlled micro-cavitation within the acoustic focal volume (30 MPa, negative pressure amplitude). By moving cavitation spots along pre-defined paths through a motorized stage, tissue-mimicking gels of different elastic moduli were cut into different shapes (rectangle, triangle, and circle), leaving behind the same shape of holes, whose sizes are less than 1 mm. The cut line width is estimated to be less than 50 um (corresponding to localized cavitation region), allowing for accurate cutting. This novel approach could open new possibility for in-vivo treatment of diseased tissues in a high-precision manner (i.e., high-precision invisible sonic scalpel).

  3. Advances in the Control System for a High Precision Dissolved Organic Carbon Analyzer

    Liao, M.; Stubbins, A.; Haidekker, M.

    2017-12-01

    Dissolved organic carbon (DOC) is a master variable in aquatic ecosystems. DOC in the ocean is one of the largest carbon stores on earth. Studies of the dynamics of DOC in the ocean and other low DOC systems (e.g. groundwater) are hindered by the lack of high precision (sub-micromolar) analytical techniques. Results are presented from efforts to construct and optimize a flow-through, wet chemical DOC analyzer. This study focused on the design, integration and optimization of high precision components and control systems required for such a system (mass flow controller, syringe pumps, gas extraction, reactor chamber with controlled UV and temperature). Results of the approaches developed are presented.

  4. A High-precision Motion Compensation Method for SAR Based on Image Intensity Optimization

    Hu Ke-bin

    2015-02-01

    Full Text Available Owing to the platform instability and precision limitations of motion sensors, motion errors negatively affect the quality of synthetic aperture radar (SAR images. The autofocus Back Projection (BP algorithm based on the optimization of image sharpness compensates for motion errors through phase error estimation. This method can attain relatively good performance, while assuming the same phase error for all pixels, i.e., it ignores the spatial variance of motion errors. To overcome this drawback, a high-precision motion error compensation method is presented in this study. In the proposed method, the Antenna Phase Centers (APC are estimated via optimization using the criterion of maximum image intensity. Then, the estimated APCs are applied for BP imaging. Because the APC estimation equals the range history estimation for each pixel, high-precision phase compensation for every pixel can be achieved. Point-target simulations and processing of experimental data validate the effectiveness of the proposed method.

  5. Laser-Induced Focused Ultrasound for Cavitation Treatment: Toward High-Precision Invisible Sonic Scalpel.

    Lee, Taehwa; Luo, Wei; Li, Qiaochu; Demirci, Hakan; Guo, L Jay

    2017-10-01

    Beyond the implementation of the photoacoustic effect to photoacoustic imaging and laser ultrasonics, this study demonstrates a novel application of the photoacoustic effect for high-precision cavitation treatment of tissue using laser-induced focused ultrasound. The focused ultrasound is generated by pulsed optical excitation of an efficient photoacoustic film coated on a concave surface, and its amplitude is high enough to produce controllable microcavitation within the focal region (lateral focus <100 µm). Such microcavitation is used to cut or ablate soft tissue in a highly precise manner. This work demonstrates precise cutting of tissue-mimicking gels as well as accurate ablation of gels and animal eye tissues. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. High-precision broad-band linear polarimetry of early-type binaries. II. Variable, phase-locked polarization in triple Algol-type system λ Tauri

    Berdyugin, A.; Piirola, V.; Sakanoi, T.; Kagitani, M.; Yoneda, M.

    2018-03-01

    Aim. To study the binary geometry of the classic Algol-type triple system λ Tau, we have searched for polarization variations over the orbital cycle of the inner semi-detached binary, arising from light scattering in the circumstellar material formed from ongoing mass transfer. Phase-locked polarization curves provide an independent estimate for the inclination i, orientation Ω, and the direction of the rotation for the inner orbit. Methods: Linear polarization measurements of λ Tau in the B, V , and R passbands with the high-precision Dipol-2 polarimeter have been carried out. The data have been obtained on the 60 cm KVA (Observatory Roque de los Muchachos, La Palma, Spain) and Tohoku 60 cm (Haleakala, Hawaii, USA) remotely controlled telescopes over 69 observing nights. Analytic and numerical modelling codes are used to interpret the data. Results: Optical polarimetry revealed small intrinsic polarization in λ Tau with 0.05% peak-to-peak variation over the orbital period of 3.95 d. The variability pattern is typical for binary systems showing strong second harmonic of the orbital period. We apply a standard analytical method and our own light scattering models to derive parameters of the inner binary orbit from the fit to the observed variability of the normalized Stokes parameters. From the analytical method, the average for three passband values of orbit inclination i = 76° + 1°/-2° and orientation Ω = 15°(195°) ± 2° are obtained. Scattering models give similar inclination values i = 72-76° and orbit orientation ranging from Ω = 16°(196°) to Ω = 19°(199°), depending on the geometry of the scattering cloud. The rotation of the inner system, as seen on the plane of the sky, is clockwise. We have found that with the scattering model the best fit is obtained for the scattering cloud located between the primary and the secondary, near the inner Lagrangian point or along the Roche lobe surface of the secondary facing the primary. The inclination i

  7. Application of MCU to intelligent interface of high precision magnet power supply

    Xu Ruinian; Li Deming

    2004-01-01

    Application of the high-capability MCU in the intelligent interface is introduced in this paper. A prototype of intelligent interface for high precision huge magnet power supply was developed successfully. This intelligent interface was composed of two parts: operation panel and main board, both of which adopt a MCU of PIC16F877 respectively. The interface has many advantages, such as small size, low cost and good interference immunity. (authors)

  8. High Precision Fast Projective Synchronization for Chaotic Systems with Unknown Parameters

    Nian, Fuzhong; Wang, Xingyuan; Lin, Da; Niu, Yujun

    2013-08-01

    A high precision fast projective synchronization method for chaotic systems with unknown parameters was proposed by introducing optimal matrix. Numerical simulations indicate that the precision be improved about three orders compared with other common methods under the same condition of software and hardware. Moreover, when average error is less than 10-3, the synchronization speed is 6500 times than common methods, the iteration needs only 4 times. The unknown parameters also were identified rapidly. The theoretical analysis and proof also were given.

  9. High precision analysis of trace lithium isotope by thermal ionization mass spectrometry

    Tang Lei; Liu Xuemei; Long Kaiming; Liu Zhao; Yang Tianli

    2010-01-01

    High precision analysis method of ng lithium by thermal ionization mass spectrometry is developed. By double-filament measurement,phosphine acid ion enhancer and sample pre-baking technique,the precision of trace lithium analysis is improved. For 100 ng lithium isotope standard sample, relative standard deviation is better than 0.086%; for 10 ng lithium isotope standard sample, relative standard deviation is better than 0.90%. (authors)

  10. The πNN coupling from high precision np charge exchange at 162 MeV

    Nilsson, J.; Blomgren, J.; Conde, H.; Elmgren, K.; Olsson, N.; Ericson, T.E.O.; Uppsala Univ.; Jonsson, O.; Nilsson, L.; Loiseau, B.; Ringbom, A.

    1995-02-01

    Differential cross sections for unpolarized neutrons of 162 MeV have been measured to high precision with particular attention to the absolute normalisation. These data can be extrapolated precisely and model-independently to the pion pole and give a πNN coupling constant g 2 =14.6±0.3 or f 2 =0.0808±0.0017. This is higher than recently suggested values. (author) 24 refs.; 3 figs.; 1 tab

  11. The Multi-energy High precision Data Processor Based on AD7606

    Zhao, Chen; Zhang, Yanchi; Xie, Da

    2017-11-01

    This paper designs an information collector based on AD7606 to realize the high-precision simultaneous acquisition of multi-source information of multi-energy systems to form the information platform of the energy Internet at Laogang with electricty as its major energy source. Combined with information fusion technologies, this paper analyzes the data to improve the overall energy system scheduling capability and reliability.

  12. A Miniaturized Colorimeter with a Novel Design and High Precision for Photometric Detection

    Jun-Chao Yan; Yan Chen; Yu Pang; Jan Slavik; Yun-Fei Zhao; Xiao-Ming Wu; Yi Yang; Si-Fan Yang; Tian-Ling Ren

    2018-01-01

    Water quality detection plays an increasingly important role in environmental protection. In this work, a novel colorimeter based on the Beer-Lambert law was designed for chemical element detection in water with high precision and miniaturized structure. As an example, the colorimeter can detect phosphorus, which was accomplished in this article to evaluate the performance. Simultaneously, a modified algorithm was applied to extend the linear measurable range. The colorimeter encompassed a ne...

  13. Research on Ship Trajectory Tracking with High Precision Based on LOS

    Hengzhi Liu

    2018-01-01

    Full Text Available Aiming at how precise to track by LOS, a method is proposed. The method combines the advantages of LOS simplicity and intuition, easy parameter setting and good convergence, with the features of GPC softening, multi-step prediction, rolling optimization and excellent controllability and robustness. In order to verify the effectiveness of the method, the method is simulated by Matlab. The simulation’s results show that it makes ship tracking highly precise.

  14. Research on the high-precision non-contact optical detection technology for banknotes

    Jin, Xiaofeng; Liang, Tiancai; Luo, Pengfeng; Sun, Jianfeng

    2015-09-01

    The technology of high-precision laser interferometry was introduced for optical measurement of the banknotes in this paper. Taking advantage of laser short wavelength and high sensitivity, information of adhesive tape and cavity about the banknotes could be checked efficiently. Compared with current measurement devices, including mechanical wheel measurement device, Infrared measurement device, ultrasonic measurement device, the laser interferometry measurement has higher precision and reliability. This will improve the ability of banknotes feature information in financial electronic equipment.

  15. Super high precision 200 ppi liquid crystal display series; Chokoseido 200 ppi ekisho display series

    NONE

    2000-03-01

    In mobile equipment, in demand is a high precision liquid crystal display (LCD) having the power of expression equivalent to printed materials like magazines because of the necessity of displaying a large amount of information on a easily potable small screen. In addition, with the spread and high-quality image of digital still cameras, it is strongly desired to display photographed digital image data in high quality. Toshiba Corp., by low temperature polysilicone (p-Si) technology, commercialized the liquid crystal display series of 200 ppi (pixels per inch) precision dealing with the rise of the high-precision high-image quality LCD market. The super high precision of 200 ppi enables the display of smooth beautiful animation comparable to printed sheets of magazines and photographs. The display series are suitable for the display of various information services such as electronic books and electronic photo-viewers including internet. The screen sizes lined up are No. 4 type VGA (640x480 pixels) of a small pocket notebook size and No. 6.3 type XGA (1,024x768 pixels) of a paperback size, with a larger screen to be furthered. (translated by NEDO)

  16. Concept of modular flexure-based mechanisms for ultra-high precision robot design

    M. Richard

    2011-05-01

    Full Text Available This paper introduces a new concept of modular flexure-based mechanisms to design industrial ultra-high precision robots, which aims at significantly reducing both the complexity of their design and their development time. This modular concept can be considered as a robotic Lego, where a finite number of building bricks is used to quickly build a high-precision robot. The core of the concept is the transformation of a 3-D design problem into several 2-D ones, which are simpler and well-mastered. This paper will first briefly present the theoretical bases of this methodology and the requirements of both types of building bricks: the active and the passive bricks. The section dedicated to the design of the active bricks will detail the current research directions, mainly the maximisation of the strokes and the development of an actuation sub-brick. As for the passive bricks, some examples will be presented, and a discussion regarding the establishment of a mechanical solution catalogue will conclude the section. Last, this modular concept will be illustrated with a practical example, consisting in the design of a 5-degree of freedom ultra-high precision robot.

  17. Recent developments for high-precision mass measurements of the heaviest elements at SHIPTRAP

    Minaya Ramirez, E.; Ackermann, D.; Blaum, K.; Block, M.; Droese, C.; Düllmann, Ch. E.; Eibach, M.; Eliseev, S.; Haettner, E.; Herfurth, F.; Heßberger, F.P.

    2013-01-01

    Highlights: • Direct high-precision mass measurements of No and Lr isotopes performed. • High-precision mass measurements with a count rate of 1 ion/hour demonstrated. • The results provide anchor points for a large region connected by alpha-decay chains. • The binding energies determine the strength of the deformed shell closure N = 152. • Technical developments and new techniques will pave the way towards heavier elements. -- Abstract: Atomic nuclei far from stability continue to challenge our understanding. For example, theoretical models have predicted an “island of stability” in the region of the superheavy elements due to the closure of spherical proton and neutron shells. Depending on the model, these are expected at Z = 114, 120 or even 126 and N = 172 or 184. Valuable information on the road to the island of stability is derived from high-precision mass measurements, which give direct access to binding energies of short-lived trans-uranium nuclei. Recently, direct mass measurements at SHIPTRAP have been extended to nobelium and lawrencium isotopes around the deformed shell gap N = 152. In order to further extend mass measurements to the region of superheavy elements, new technical developments are required to increase the performance of our setup. The sensitivity will increase through the implementation of a new detection method, where observation of one single ion is sufficient. Together with the use of a more efficient gas stopping cell, this will us allow to significantly enhance the overall efficiency of SHIPTRAP

  18. Local high precision 3D measurement based on line laser measuring instrument

    Zhang, Renwei; Liu, Wei; Lu, Yongkang; Zhang, Yang; Ma, Jianwei; Jia, Zhenyuan

    2018-03-01

    In order to realize the precision machining and assembly of the parts, the geometrical dimensions of the surface of the local assembly surfaces need to be strictly guaranteed. In this paper, a local high-precision three-dimensional measurement method based on line laser measuring instrument is proposed to achieve a high degree of accuracy of the three-dimensional reconstruction of the surface. Aiming at the problem of two-dimensional line laser measuring instrument which lacks one-dimensional high-precision information, a local three-dimensional profile measuring system based on an accurate single-axis controller is proposed. First of all, a three-dimensional data compensation method based on spatial multi-angle line laser measuring instrument is proposed to achieve the high-precision measurement of the default axis. Through the pretreatment of the 3D point cloud information, the measurement points can be restored accurately. Finally, the target spherical surface is needed to make local three-dimensional scanning measurements for accuracy verification. The experimental results show that this scheme can get the local three-dimensional information of the target quickly and accurately, and achieves the purpose of gaining the information and compensating the error for laser scanner information, and improves the local measurement accuracy.

  19. Video-rate or high-precision: a flexible range imaging camera

    Dorrington, Adrian A.; Cree, Michael J.; Carnegie, Dale A.; Payne, Andrew D.; Conroy, Richard M.; Godbaz, John P.; Jongenelen, Adrian P. P.

    2008-02-01

    A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications. Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system's frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution. In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.

  20. Constraining convection parameters from the light curve shapes of pulsating white dwarf stars: the cases of EC 14012-1446 and WD 1524-0030

    Handler, G; Lendl, M; Beck, P [Institut fuer Astronomie, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180 Wien (Austria); Provencal, J L; Montgomery, M H [Mt. Cuba Observatory and Department of Physics and Astronomy, University of Delaware, 223 Sharp Laboratory, Newark, DE 19716 (Cuba); Romero-Colmenero, E [South AfricAN Astronomical Observatory, PO Box 9, Observatory 7935 (South Africa); Sanchawala, K; Chen, W-P [Graduate Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Wood, M A; Silver, I [Department of Physics and Space Sciences and SARA Observatory, Florida Institute of Technology, Melbourne, FL 32901 (United States)], E-mail: handler@astro.univie.ac.at

    2008-10-15

    Montgomery [1] developed a method to probe convection in pulsating white dwarf stars which allows the recovery of the thermal response time of the convection zone by fitting observed nonsinusoidal light curves. He applied this method to two objects; the Whole Earth Telescope (WET) observed the pulsating DB white dwarf GD 358 for just this purpose. Given this WET run's success, it is time to extend Montgomery's method to pulsating DA white dwarf (ZZ Ceti) stars. We present observations of two ZZ Ceti stars, WD 1524-0030 and EC 14012-1446, both observed from multiple sites. EC 14012-1446 seems better suited thAN WD1524-0030 for a future WET run because it has more pulsation modes excited and because it pulsation spectrum appears to be more stable in time. We call for participation in this effort to take place in April 2008.

  1. The Complete Light-curve Sample of Spectroscopically Confirmed SNe Ia from Pan-STARRS1 and Cosmological Constraints from the Combined Pantheon Sample

    Scolnic, D. M.; Jones, D. O.; Rest, A.; Pan, Y. C.; Chornock, R.; Foley, R. J.; Huber, M. E.; Kessler, R.; Narayan, G.; Riess, A. G.; Rodney, S.; Berger, E.; Brout, D. J.; Challis, P. J.; Drout, M.; Finkbeiner, D.; Lunnan, R.; Kirshner, R. P.; Sanders, N. E.; Schlafly, E.; Smartt, S.; Stubbs, C. W.; Tonry, J.; Wood-Vasey, W. M.; Foley, M.; Hand, J.; Johnson, E.; Burgett, W. S.; Chambers, K. C.; Draper, P. W.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R. P.; Magnier, E. A.; Metcalfe, N.; Bresolin, F.; Gall, E.; Kotak, R.; McCrum, M.; Smith, K. W.

    2018-06-01

    We present optical light curves, redshifts, and classifications for 365 spectroscopically confirmed Type Ia supernovae (SNe Ia) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. We detail improvements to the PS1 SN photometry, astrometry, and calibration that reduce the systematic uncertainties in the PS1 SN Ia distances. We combine the subset of 279 PS1 SNe Ia (0.03 Ia from the Sloan Digital Sky Survey (SDSS), SNLS, and various low-z and Hubble Space Telescope samples to form the largest combined sample of SNe Ia, consisting of a total of 1048 SNe Ia in the range of 0.01 Ia to measure dark energy.

  2. BEER ANALYSIS OF KEPLER AND CoRoT LIGHT CURVES. I. DISCOVERY OF KEPLER-76b: A HOT JUPITER WITH EVIDENCE FOR SUPERROTATION

    Faigler, S.; Tal-Or, L.; Mazeh, T.; Latham, D. W.; Buchhave, L. A.

    2013-01-01

    We present the first case in which the BEER algorithm identified a hot Jupiter in the Kepler light curve, and its reality was confirmed by orbital solutions based on follow-up spectroscopy. The companion Kepler-76b was identified by the BEER algorithm, which detected the BEaming (sometimes called Doppler boosting) effect together with the Ellipsoidal and Reflection/emission modulations (BEER), at an orbital period of 1.54 days, suggesting a planetary companion orbiting the 13.3 mag F star. Further investigation revealed that this star appeared in the Kepler eclipsing binary catalog with estimated primary and secondary eclipse depths of 5 × 10 –3 and 1 × 10 –4 , respectively. Spectroscopic radial velocity follow-up observations with Tillinghast Reflector Echelle Spectrograph and SOPHIE confirmed Kepler-76b as a transiting 2.0 ± 0.26 M Jup hot Jupiter. The mass of a transiting planet can be estimated from either the beaming or the ellipsoidal amplitude. The ellipsoidal-based mass estimate of Kepler-76b is consistent with the spectroscopically measured mass while the beaming-based estimate is significantly inflated. We explain this apparent discrepancy as evidence for the superrotation phenomenon, which involves eastward displacement of the hottest atmospheric spot of a tidally locked planet by an equatorial superrotating jet stream. This phenomenon was previously observed only for HD 189733b in the infrared. We show that a phase shift of 10.°3 ± 2.°0 of the planet reflection/emission modulation, due to superrotation, explains the apparently inflated beaming modulation, resolving the ellipsoidal/beaming amplitude discrepancy. Kepler-76b is one of very few confirmed planets in the Kepler light curves that show BEER modulations and the first to show superrotation evidence in the Kepler band. Its discovery illustrates for the first time the ability of the BEER algorithm to detect short-period planets and brown dwarfs.

  3. Power spectra decomposition of 36 RS CVn UBV photometric light curves from the first two years of the automatic photoelectric telescope

    Nelson, E.R.

    1988-01-01

    The first search for multiple periodic structure of a major subset of the RS CVn class of interacting binary stars systems, using a rigorous numerical approach appropriate to unevenly-spaced gapped data, is presented. The main intent of this dissertation is to characterize properly the power spectral content of RS CVn binary light curves and describe how this information can constrain the current models for the systems. If the light curve can be considered as a tracer of stellar surface activity, then the photometric distortions can be used to characterize magnetic activity cycles and add to the understanding of stellar dynamics. Most of the systems exhibit multiple periodic structure, 40% of which show changes in the photometric period on a time scale of a few hundred days. A preference is observed for photometric periods with time scales near the orbital and half orbital periods. The effect is particularly strong for the shorter period systems and is interpreted as evidence for synchronous, or near synchronous, rotation. A strong linear correlation in the periods for the multiply periodic systems is observed which indicates a preferential pairing of spot groups on the stellar surface. No correlation is found for the relative phases of the multiple periodic signals. Changes in the photometric period are associated with variations in the amplitude of the distortion wave, which would indicate the growth and decay of spot groups. The growth and decay of pairs of spot groups, arbitrarily separated in phase, on a differentially rotating star is the model most consistent with the results of my analysis

  4. THE RADIO LIGHT CURVE OF THE GAMMA-RAY NOVA IN V407 CYG: THERMAL EMISSION FROM THE IONIZED SYMBIOTIC ENVELOPE, DEVOURED FROM WITHIN BY THE NOVA BLAST

    Chomiuk, Laura; Krauss, Miriam I.; Rupen, Michael P.; Roy, Nirupam; Mioduszewski, Amy [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Nelson, Thomas [School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Sokoloski, Jennifer L.; Weston, Jennifer [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Mukai, Koji [CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Munari, Ulisse [INAF Astronomical Observatory of Padova, I-36012 Asiago (VI) (Italy); O' Brien, Tim J. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom); Eyres, Stewart P. S. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Bode, Michael F., E-mail: chomiuk@pa.msu.edu [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)

    2012-12-20

    We present multi-frequency radio observations of the 2010 nova event in the symbiotic binary V407 Cygni, obtained with the Karl G. Jansky Very Large Array (VLA) and spanning 1-45 GHz and 17-770 days following discovery. This nova-the first ever detected in gamma rays-shows a radio light curve dominated by the wind of the Mira giant companion, rather than the nova ejecta themselves. The radio luminosity grew as the wind became increasingly ionized by the nova outburst, and faded as the wind was violently heated from within by the nova shock. This study marks the first time that this physical mechanism has been shown to dominate the radio light curve of an astrophysical transient. We do not observe a thermal signature from the nova ejecta or synchrotron emission from the shock, due to the fact that these components were hidden behind the absorbing screen of the Mira wind. We estimate a mass-loss rate for the Mira wind of M-dot{sub w} approx. 10{sup -6} M{sub Sun} yr{sup -1}. We also present the only radio detection of V407 Cyg before the 2010 nova, gleaned from unpublished 1993 archival VLA data, which shows that the radio luminosity of the Mira wind varies by a factor of {approx}>20 even in quiescence. Although V407 Cyg likely hosts a massive accreting white dwarf, making it a candidate progenitor system for a Type Ia supernova, the dense and radially continuous circumbinary material surrounding V407 Cyg is inconsistent with observational constraints on the environments of most Type Ia supernovae.

  5. The X-ray Power Density Spectrum of the Seyfert 2 Galaxy NGC 4945: Analysis and Application of the Method of Light Curve Simulations

    Mueller, Martin; /SLAC

    2010-12-16

    The study of the power density spectrum (PDS) of fluctuations in the X-ray flux from active galactic nuclei (AGN) complements spectral studies in giving us a view into the processes operating in accreting compact objects. An important line of investigation is the comparison of the PDS from AGN with those from galactic black hole binaries; a related area of focus is the scaling relation between time scales for the variability and the black hole mass. The PDS of AGN is traditionally modeled using segments of power laws joined together at so-called break frequencies; associations of the break time scales, i.e., the inverses of the break frequencies, with time scales of physical processes thought to operate in these sources are then sought. I analyze the Method of Light Curve Simulations that is commonly used to characterize the PDS in AGN with a view to making the method as sensitive as possible to the shape of the PDS. I identify several weaknesses in the current implementation of the method and propose alternatives that can substitute for some of the key steps in the method. I focus on the complications introduced by uneven sampling in the light curve, the development of a fit statistic that is better matched to the distributions of power in the PDS, and the statistical evaluation of the fit between the observed data and the model for the PDS. Using archival data on one AGN, NGC 3516, I validate my changes against previously reported results. I also report new results on the PDS in NGC 4945, a Seyfert 2 galaxy with a well-determined black hole mass. This source provides an opportunity to investigate whether the PDS of Seyfert 1 and Seyfert 2 galaxies differ. It is also an attractive object for placement on the black hole mass-break time scale relation. Unfortunately, with the available data on NGC 4945, significant uncertainties on the break frequency in its PDS remain.

  6. The Prompt-afterglow Connection in Gamma-ray Bursts: a Comprehensive Statistical Analysis of Swift X-ray Light-curves

    Margutti, R.; Zaninoni, E.; Bernardini, M. G.; Chincarini, G.; Pasotti, F.; Guidorzi, C.; Angelini, Lorella; Burrows, D. N.; Capalbi, M.; Evans, P. A.; hide

    2012-01-01

    We present a comprehensive statistical analysis of Swift X-ray light-curves of Gamma- Ray Bursts (GRBs) collecting data from more than 650 GRBs discovered by Swift and other facilities. The unprecedented sample size allows us to constrain the rest-frame X-ray properties of GRBs from a statistical perspective, with particular reference to intrinsic time scales and the energetics of the different light-curve phases in a common rest-frame 0.3-30 keV energy band. Temporal variability episodes are also studied and their properties constrained. Two fundamental questions drive this effort: i) Does the X-ray emission retain any kind of "memory" of the prompt ?-ray phase? ii) Where is the dividing line between long and short GRB X-ray properties? We show that short GRBs decay faster, are less luminous and less energetic than long GRBs in the X-rays, but are interestingly characterized by similar intrinsic absorption. We furthermore reveal the existence of a number of statistically significant relations that link the X-ray to prompt ?-ray parameters in long GRBs; short GRBs are outliers of the majority of these 2-parameter relations. However and more importantly, we report on the existence of a universal 3-parameter scaling that links the X-ray and the ?-ray energy to the prompt spectral peak energy of both long and short GRBs: E(sub X,iso)? E(sup 1.00+/-0.06)(sub ?,iso) /E(sup 0.60+/-0.10)(sub pk).

  7. The Radio Light Curve of the Gamma-Ray Nova in V407 CYG: Thermal Emission from the Ionized Symbiotic Envelope, Devoured from Within by the Nova Blast

    Chomiuk, Laura; Krauss, Miriam I.; Rupen, Michael P.; Nelson, Thomas; Roy, Nirupam; Sokoloski, Jennifer L.; Mukai, Koji; Munari, Ulisse; Mioduszewski, Amy; Weston, Jeninfer; hide

    2012-01-01

    We present multi-frequency radio observations of the 2010 nova event in the symbiotic binary V407 Cygni, obtained with the Karl G. Jansky Very Large Array (VLA) and spanning 1.45 GHz and 17.770 days following discovery. This nova.the first ever detected in gamma rays.shows a radio light curve dominated by the wind of the Mira giant companion, rather than the nova ejecta themselves. The radio luminosity grewas the wind became increasingly ionized by the nova outburst, and faded as the wind was violently heated from within by the nova shock. This study marks the first time that this physical mechanism has been shown to dominate the radio light curve of an astrophysical transient. We do not observe a thermal signature from the nova ejecta or synchrotron emission from the shock, due to the fact that these components were hidden behind the absorbing screen of the Mira wind. We estimate a mass-loss rate for the Mira wind of .Mw approximately equals 10(exp -6) Solar mass yr(exp -1). We also present the only radio detection of V407 Cyg before the 2010 nova, gleaned from unpublished 1993 archival VLA data, which shows that the radio luminosity of the Mira wind varies by a factor of 20 even in quiescence. Although V407 Cyg likely hosts a massive accreting white dwarf, making it a candidate progenitor system for a Type Ia supernova, the dense and radially continuous circumbinary material surrounding V407 Cyg is inconsistent with observational constraints on the environments of most Type Ia supernovae.

  8. A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning

    Zuo, Wenwei; Guo, Chi; Liu, Jingnan; Peng, Xuan; Yang, Min

    2018-01-01

    Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI) exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS)/Global Positioning System (GPS) positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API) of the original standard Global Navigation Satellite System (GNSS) to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to meet the

  9. A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning

    Wenwei Zuo

    2018-01-01

    Full Text Available Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS/Global Positioning System (GPS positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API of the original standard Global Navigation Satellite System (GNSS to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to

  10. A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning.

    Zuo, Wenwei; Guo, Chi; Liu, Jingnan; Peng, Xuan; Yang, Min

    2018-01-10

    Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI) exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS)/Global Positioning System (GPS) positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API) of the original standard Global Navigation Satellite System (GNSS) to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to meet the

  11. Lighting.

    United States. Bonneville Power Administration.

    1992-09-01

    Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

  12. Validation of Kepler's multiple planet candidates. III. Light curve analysis and announcement of hundreds of new multi-planet systems

    Rowe, Jason F.; Bryson, Stephen T.; Lissauer, Jack J.; Jontof-Hutter, Daniel; Mullally, Fergal; Howell, Steve B.; Borucki, William J.; Haas, Michael; Huber, Daniel; Thompson, Susan E.; Quintana, Elisa; Barclay, Thomas; Still, Martin; Marcy, Geoffrey W.; Issacson, Howard; Gilliland, Ronald L.; Ford, Eric; Steffen, Jason H.; Fortney, Jonathan; Gautier, T. N. III

    2014-01-01

    The Kepler mission has discovered more than 2500 exoplanet candidates in the first two years of spacecraft data, with approximately 40% of those in candidate multi-planet systems. The high rate of multiplicity combined with the low rate of identified false positives indicates that the multiplanet systems contain very few false positive signals due to other systems not gravitationally bound to the target star. False positives in the multi-planet systems are identified and removed, leaving behind a residual population of candidate multi-planet transiting systems expected to have a false positive rate less than 1%. We present a sample of 340 planetary systems that contain 851 planets that are validated to substantially better than the 99% confidence level; the vast majority of these have not been previously verified as planets. We expect ∼two unidentified false positives making our sample of planet very reliable. We present fundamental planetary properties of our sample based on a comprehensive analysis of Kepler light curves, ground-based spectroscopy, and high-resolution imaging. Since we do not require spectroscopy or high-resolution imaging for validation, some of our derived parameters for a planetary system may be systematically incorrect due to dilution from light due to additional stars in the photometric aperture. Nonetheless, our result nearly doubles the number verified exoplanets.

  13. Lighting

    Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...

  14. Rigorous high-precision enclosures of fixed points and their invariant manifolds

    Wittig, Alexander N.

    The well established concept of Taylor Models is introduced, which offer highly accurate C0 enclosures of functional dependencies, combining high-order polynomial approximation of functions and rigorous estimates of the truncation error, performed using verified arithmetic. The focus of this work is on the application of Taylor Models in algorithms for strongly non-linear dynamical systems. A method is proposed to extend the existing implementation of Taylor Models in COSY INFINITY from double precision coefficients to arbitrary precision coefficients. Great care is taken to maintain the highest efficiency possible by adaptively adjusting the precision of higher order coefficients in the polynomial expansion. High precision operations are based on clever combinations of elementary floating point operations yielding exact values for round-off errors. An experimental high precision interval data type is developed and implemented. Algorithms for the verified computation of intrinsic functions based on the High Precision Interval datatype are developed and described in detail. The application of these operations in the implementation of High Precision Taylor Models is discussed. An application of Taylor Model methods to the verification of fixed points is presented by verifying the existence of a period 15 fixed point in a near standard Henon map. Verification is performed using different verified methods such as double precision Taylor Models, High Precision intervals and High Precision Taylor Models. Results and performance of each method are compared. An automated rigorous fixed point finder is implemented, allowing the fully automated search for all fixed points of a function within a given domain. It returns a list of verified enclosures of each fixed point, optionally verifying uniqueness within these enclosures. An application of the fixed point finder to the rigorous analysis of beam transfer maps in accelerator physics is presented. Previous work done by

  15. High-precision comparison of the antiproton-to-proton charge-to-mass ratio.

    Ulmer, S; Smorra, C; Mooser, A; Franke, K; Nagahama, H; Schneider, G; Higuchi, T; Van Gorp, S; Blaum, K; Matsuda, Y; Quint, W; Walz, J; Yamazaki, Y

    2015-08-13

    Invariance under the charge, parity, time-reversal (CPT) transformation is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry--that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime--although it is model dependent. A number of high-precision CPT and Lorentz invariance tests--using a co-magnetometer, a torsion pendulum and a maser, among others--have been performed, but only a few direct high-precision CPT tests that compare the fundamental properties of matter and antimatter are available. Here we report high-precision cyclotron frequency comparisons of a single antiproton and a negatively charged hydrogen ion (H(-)) carried out in a Penning trap system. From 13,000 frequency measurements we compare the charge-to-mass ratio for the antiproton (q/m)p- to that for the proton (q/m)p and obtain (q/m)p-/(q/m)p − 1 =1(69) × 10(-12). The measurements were performed at cyclotron frequencies of 29.6 megahertz, so our result shows that the CPT theorem holds at the atto-electronvolt scale. Our precision of 69 parts per trillion exceeds the energy resolution of previous antiproton-to-proton mass comparisons as well as the respective figure of merit of the standard model extension by a factor of four. In addition, we give a limit on sidereal variations in the measured ratio of baryonic antimatter, and it sets a new limit on the gravitational anomaly parameter of |α − 1| < 8.7 × 10(-7).

  16. Progress Towards a High-Precision Infrared Spectroscopic Survey of the H_3^+ Ion

    Perry, Adam J.; Hodges, James N.; Markus, Charles R.; Kocheril, G. Stephen; Jenkins, Paul A., II; McCall, Benjamin J.

    2015-06-01

    The trihydrogen cation, H_3^+, represents one of the most important and fundamental molecular systems. Having only two electrons and three nuclei, H_3^+ is the simplest polyatomic system and is a key testing ground for the development of new techniques for calculating potential energy surfaces and predicting molecular spectra. Corrections that go beyond the Born-Oppenheimer approximation, including adiabatic, non-adiabatic, relativistic, and quantum electrodynamic corrections are becoming more feasible to calculate. As a result, experimental measurements performed on the H_3^+ ion serve as important benchmarks which are used to test the predictive power of new computational methods. By measuring many infrared transitions with precision at the sub-MHz level it is possible to construct a list of the most highly precise experimental rovibrational energy levels for this molecule. Until recently, only a select handful of infrared transitions of this molecule have been measured with high precision (˜ 1 MHz). Using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, we are aiming to produce the largest high-precision spectroscopic dataset for this molecule to date. Presented here are the current results from our survey along with a discussion of the combination differences analysis used to extract the experimentally determined rovibrational energy levels. O. Polyansky, et al., Phil. Trans. R. Soc. A (2012), 370, 5014. M. Pavanello, et al., J. Chem. Phys. (2012), 136, 184303. L. Diniz, et al., Phys. Rev. A (2013), 88, 032506. L. Lodi, et al., Phys. Rev. A (2014), 89, 032505. J. Hodges, et al., J. Chem. Phys (2013), 139, 164201.

  17. Proceedings, High-Precision $\\alpha_s$ Measurements from LHC to FCC-ee

    d' Enterria, David [CERN; Skands, Peter Z. [Monash U.

    2015-01-01

    This document provides a writeup of all contributions to the workshop on "High precision measurements of $\\alpha_s$: From LHC to FCC-ee" held at CERN, Oct. 12--13, 2015. The workshop explored in depth the latest developments on the determination of the QCD coupling $\\alpha_s$ from 15 methods where high precision measurements are (or will be) available. Those include low-energy observables: (i) lattice QCD, (ii) pion decay factor, (iii) quarkonia and (iv) $\\tau$ decays, (v) soft parton-to-hadron fragmentation functions, as well as high-energy observables: (vi) global fits of parton distribution functions, (vii) hard parton-to-hadron fragmentation functions, (viii) jets in $e^\\pm$p DIS and $\\gamma$-p photoproduction, (ix) photon structure function in $\\gamma$-$\\gamma$, (x) event shapes and (xi) jet cross sections in $e^+e^-$ collisions, (xii) W boson and (xiii) Z boson decays, and (xiv) jets and (xv) top-quark cross sections in proton-(anti)proton collisions. The current status of the theoretical and experimental uncertainties associated to each extraction method, the improvements expected from LHC data in the coming years, and future perspectives achievable in $e^+e^-$ collisions at the Future Circular Collider (FCC-ee) with $\\cal{O}$(1--100 ab$^{-1}$) integrated luminosities yielding 10$^{12}$ Z bosons and jets, and 10$^{8}$ W bosons and $\\tau$ leptons, are thoroughly reviewed. The current uncertainty of the (preliminary) 2015 strong coupling world-average value, $\\alpha_s(m_Z)$ = 0.1177 $\\pm$ 0.0013, is about 1\\%. Some participants believed this may be reduced by a factor of three in the near future by including novel high-precision observables, although this opinion was not universally shared. At the FCC-ee facility, a factor of ten reduction in the $\\alpha_s$ uncertainty should be possible, mostly thanks to the huge Z and W data samples available.

  18. High precision instrumentation for measuring the true exposure time in diagnostic X-ray examinations

    Silva, Danubia B.; Santos, Marcus A.P.; Barros, Fabio R.; Santos, Luiz A.P.

    2013-01-01

    One of the most important physical quantities to be evaluated in diagnostic radiology is the radiation exposure time experimented by the patient during the X-ray examination. IAEA and WHO organizations have suggested that any country must create a quality surveillance program to verify if each type of ionizing radiation equipment used in the hospitals and medical clinics are in conformity with the accepted uncertainties following the international standards. The purpose of this work is to present a new high precision methodology for measuring true exposure time in diagnostic X-ray examinations: pulsed, continuous or digital one. An electronic system named CronoX, which will be soon registered at the Brazilian Patent Office (INPI), is the equipment that provides such a high precision measurement. The principle of measurement is based on the electrical signal captured by a sensor that enters in a regeneration amplifier to transform it in a digital signal, which is treated by a microprocessor (uP). The signal treatment results in a two measured times: 1) T rx , the true X-ray exposure time; 2) T nx , the time in which the X-ray machine is repeatedly cut off during the pulsed irradiation and there is no delivery dose to the patient. Conventional Polymat X-ray equipment and dental X-ray machines were used to generate X-ray photons and take the measurements with the electronic systems. The results show that such a high precision instrumentation displays the true exposure time in diagnostic X-ray examinations and indicates a new method to be purposed for the quality surveillance programs in radiology. (author)

  19. Highly precise (liquid + liquid) equilibrium and heat capacity measurements near the critical point for [Bmim][BF4] + 1H, 1H, 2H, 2H perfluoroctanol

    Pérez-Sánchez, G.; Troncoso, J.; Losada-Pérez, P.; Méndez-Castro, P.; Romaní, L.

    2013-01-01

    Highlights: • Highly precise liquid–liquid curves for [Bmi